GOST R 56512-2015
GOST R 56512−2015 nondestructive testing. Magnetic particle method. Typical processes
GOST R 56512−2015
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
NONDESTRUCTIVE TESTING
Magnetic particle inspection
Typical processes
Non-destructive testing. Method of magneting particle testing. Standard technological processes
OKS 17.220.99
77.040.20
Date of introduction 2016−06−01
Preface
1 DEVELOPED by the Federal state unitary enterprise «all-Russian research Institute for optical and physical measurements» (FGUP «VNIIOFI»), SIC ERAT 4 TSNII Minoborony of Russia, MSIA «Spectrum"
2 SUBMITTED by the Technical Committee TC 371 «NDT"
3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology dated 6 July 2015 N 875-St
4 INTRODUCED FOR THE FIRST TIME
Application rules of this standard are established in GOST R 1.0−2012 (section 8). Information about the changes to this standard is published in the annual (as of January 1 of the current year) reference index «National standards» and the official text changes and amendments — in monthly information index «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a future issue of monthly index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet (www.gost.ru)
Introduction
This standard is a technological addition to the GOST R ISO 9934−1-2011"nondestructive testing. Magnetic particle method. Part 1. Basic requirements», GOST R ISO 9934−2 and GOST R 53700−2009 (ISO 9934−3:2002).
The standard applies to magnetic particle inspection of objects made from magnetically soft and magnetically hard steels, with the use of the methods of applied magnetic fields and residual magnetization. The standards include the technical capabilities of magnetic particle inspection, recommendations on the choice of controls and the implementation of technological operations of control of the magnetization control objects, applying them to the magnetic indicator and the inspection of objects for defects, their evaluation, the distinction between real defects and false registration of testing results, demagnetization of objects and the implementation of the final operations. Given the safety requirements when performing magnetic particle inspection, taking into account the provisions of national normative documents.
1 Scope
This standard applies to magnetic particle method of nondestructive testing of semi-finished products, parts, components, subassemblies, products and other objects made of ferromagnetic materials with a relative magnetic permeability of at least 40 — steel of ordinary quality, quality carbon, low-alloy and high-alloy steels (hereinafter — the objects) in terms of production, repair and maintenance.
2 Normative references
This standard uses the regulatory references to the following standards:
GOST R 8.563−2009 State system for ensuring the uniformity of measurements. Techniques (methods) of measurements
GOST R 55612−2013 nondestructive testing magnetic. Terms and definitions
GOST R ISO 9934−2-2011 nondestructive testing. Magnetic particle method. Part 2. The radiographic materials
GOST R 53700−2009 (ISO 9934−3:2002) nondestructive testing. Magnetic particle method. Part 3. Equipment
GOST 12.0.004−90 System of standards of occupational safety. Organization of training safety. General provisions
GOST 12.1.001−89 System safety standards. Ultrasound. General safety requirements
GOST 12.1.003−83 System of standards of occupational safety. Noise. General safety requirements
GOST 12.1.004−91 System safety standards. Fire safety. General requirements
GOST 12.1.005−88 standards System of labor safety. General hygiene requirements for working zone air
GOST 12.1.030−81 System of standards of occupational safety. Electrical safety. Protective grounding, neutral earthing
GOST 12.2.003−91 System safety standards. Equipment production. General safety requirements
GOST
GOST
GOST 12.2.032−78 System safety standards. Workplace while performing work while seated. General ergonomic requirements
GOST 12.2.033−78 System safety standards. Workplace while performing work while standing. General ergonomic requirements
GOST 12.2.049−80 standards System of labor safety. Equipment production. General ergonomic requirements
GOST 12.2.061−81 System of standards of occupational safety. Equipment production. General safety requirements to working places
GOST 12.2.064−81 System of standards of occupational safety. Controls production equipment. General safety requirements
GOST 12.3.002−75 System safety standards. The process of production. General safety requirements
GOST 12.3.005−75 System safety standards. Work painting. General safety requirements
GOST 12.3.020−80 standards System of labor safety. The process of movement of goods in the enterprises. General safety requirements
GOST 12.4.011−89 System safety standards. Means of protection of workers. General requirements and classification
GOST 12.4.021−75 System safety standards. System ventilation. General requirements
GOST 12.4.023−84 System of standards of occupational safety. Protective face shields. General technical requirements and methods of control
GOST 12.4.068−79 System of standards of occupational safety. PPE dermatological. Classification and General requirements
GOST 12.4.103−83 System of standards of occupational safety. Special protective clothing, means of individual protection of feet and hands. Classification
GOST 12.4.238−2013 System safety standards. Breathing apparatus of the air insulation. General technical requirements and test methods
GOST
GOST 33−2000 Petroleum products. Transparent and opaque liquids. Determination of kinematic viscosity and calculation of dynamic viscosity
GOST 1435−99 Bars, strips and reels of tool unalloyed steel. General specifications
GOST 2789−73 surface Roughness. Parameters and characteristics
GOST 5632−2014 Alloyed stainless steels and alloys corrosion-resistant, heatresistant and heat-proof. Brand
GOST 9070−75 Viscometers for determination of relative viscosity of paint materials. Specifications
GOST 9411−91 Glass optical color. Specifications
GOST 10028−81 Viscometers glass capillary. Specifications
Note — When using this standard appropriate to test the effect of reference standards in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet or in the annual information index «National standards» published as on January 1 of the current year, and the editions of the monthly information index «National standards» for the current year. If replaced with a reference standard, which was given an undated reference, then it is recommended to use the current version of this standard, taking into account all enabled in this version modifications. If replaced with a reference standard, which is given a dated reference, it is recommended to use the version of this standard referred to above by year of approval (acceptance). If after approval of this standard in the reference standard, which is given a dated reference, a change affecting a provision to which reference, the provision is recommended to be applied without taking into account this change. If the reference standard is cancelled without replacement, the position in which reference is made to him, recommended to be used in part not affecting this link.
3 Terms and definitions
This standard applies the following terms with respective definitions:
3.1 defect (defect): Each separate discrepancy of products to the established requirements.
3.2 defect surface (subsurface discontinuity): a Defect reaching the surface of the test object.
3.3 the defect is subsurface (near surface discontinuity): Defect located near the surface of the test object and not facing the surface.
3.4 the defects recording (magnetogram; magnetic seismogram; off volume control dimension recorded seismogram): the Image display pattern defect of the object material or control sample, is recorded on the pictures in the layer of lacquer, tape or other medium.
3.5 measuring the magnetic field strength (measuring instrument of intensity of a magnetic field): magnetic measuring device, the scale of which is graduated in units of magnetic field strength.
3.6 display pattern defect (flaw indications; indicating pictorial representation of defect): the Image formed by the magnetic powder on the surface of the test object at the location of the defect, approximately similar to the shape of the defect on the surface of the test object.
3.7 cable (cable): One or more twisted insulated flexible conductors designed for the taping of the object of control with a view to their longitudinal or toroidal magnetization or demagnetization.
3.8 control sample (test piece; the test specimen): a Special product or production unit with natural or artificial defects in the form of discontinuities or other inhomogeneities of the material of known dimensions, is designed to verify that the funds of the IPC by identifying these defects at a given control technology, as well as to conduct works on determination of the threshold sensitivity of the process to the IPC.
3.9 short detail (short detail): Detail with a ratio of length to equivalent diameter of less than three.
3.10 the coercive force (by induction) (coercive force): the Value equal to magnetic field intensity necessary to change magnetic induction from residual induction to zero.
3.11 the coefficient of magnetic sensitivity indicators: the Relative integral index identifying the ability of magnetic suspensions and powders is determined using a specialized device as the ratio of the minimum magnetic stray field is taken as 1, the minimum field strength of scattering, in which the defect is detected the investigated magnetic suspension or powder.
3.12 about (imaginary) defect [imaginary (sham) defect]: a concentration of powder that looks identical to the tracer trail from a defect in the absence of the defect.
3.13 fluorescent magnetic powder (magnetic particles fluorescent): Magnetic powder, the particles of which are covered needlewoman film phosphor.
3.14 magnetic powder (magnetic particles): the Powder of the ferromagnetic material used as the indicator of the magnetic stray field.
3.15 soft magnetic material (soft magnetic material) Magnetic material with coercive force by induction, not more than 4 kA/m.
3.16 magnetic particle inspection method (magnetic particle nondestructive inspection; magnetic particle examination): non-destructive testing Method based on registration of magnetic stray fields over the defects using the quality indicator of the ferromagnetic powder or magnetic suspension.
3.17 hard magnetic material (hard magnetic material) Magnetic material with coercive force by induction of at least 4 kA/m.
3.18 normal component of magnetic field intensity [normal (indicate instead) component magnetic field strength]: Component of magnetic field directed perpendicular to the surface of the object in the control zone.
3.19 residual magnetic field (residual magnetic field): Magnetic field produced in the space of a ferromagnetic material of the test object due to its magnetization after removing the external magnetic field.
3.20 residual magnetization of the test object; residual magnetic induction (remanent magnetization; remanence; retentivity): the Magnetization (induction), which is the object of control after removal of the external magnetic field.
3.21 the area of effective magnetization (magnetize effective area): the Area on the surface of the magnetized object within which the tangential component of the magnetic field sufficient for the MPK, and the ratio of the normal and tangential components of magnetic field intensity less than or equal to 3.
3.22 the applied magnetic field (applied magnetic field): the External magnetic field exceeding the magnetic field of the Earth, in which the object is magnetic particle inspection or part thereof during the inspection.
3.23 stray field of a defect; the stray field (leakage flux field; magnetic dispersion): One of the components of the magnetic field of the defect is due to a change of direction of the magnetic flux in the material test object due to local changes of magnetic permeability of the material in the area of the defect.
3.24 demagnetization (demagnetization; magnetic neutralization): the Operation of magnetic particle inspection, which under the influence of an external magnetic field reduces the magnetization of the object material to an acceptable level.
3.25 the solenoid (solenoid): a Hollow cylindrical inductance coil, the passage along which an electric current, a magnetic field, magnetizing or demagnetizing the object placed in the cavity of the solenoid or near its end.
3.26 the tangential component of magnetic field intensity (tangential magnetic field strength component): Component of magnetic field directed parallel to the surface of the object in the control zone.
3.27 the teslameter (teslameter): magnetic measuring instrument designed to measure magnetic induction, the scale of which is calibrated in Tesla.
3.28 a ferromagnetic material; a magnetic material (ferromagnet; ferromagnetic; magnetic material): a Material with the properties of the ferromagnetic or ferrimagnetic.
Note — Ferromagnetic materials are characterized by residual induction, magnetic susceptibility, magnetic permeability, coercive force and other characteristics. These materials are divided into two main classes: soft and hard magnetic.
3.29 the colored magnetic powder (magnetic particles coloured): According to GOST R 55612.
3.30 a Central conductor (central conductor): a Conductor that is inserted inside of a hollow object or in the existing hole, through which an electrical current is passed in a circular magnetization of the test object.
3.31 equivalent diameter (details) [equiavalent diameter (detail)]: Diameter of a circle with an area equal to the cross sectional area of the part.
3.32 electrical contacts (electrical contact; contactor; electric feeler): the Device for magnetizing local areas of large-size objects control by passing current on them.
3.33 the electromagnet (electromagnet): Magnetizing and demagnetizing device is typically in the form of a U-shaped ferromagnetic core, which is wound with one, two or more windings included according to the passage which of the electric current in the core occurs and concentrates the magnetic field that is magnetized or demagnetized object located in the interpolar space of the electromagnet.
4 Symbols and abbreviations
4.1 this standard applies the following abbreviations:
Kzu — pin clamping device;
IPC — magnetic particle inspection;
NTD — normative and technical documentation;
The SLEEP method of the residual magnetization;
The WBS method the applied field;
TMS — detergent;
TU — technical conditions;
UV — ultraviolet.
4.2 this standard applies the following symbols of types and methods of magnetization and of the magnetizing current view:
C — circular magnetization;
TSO — circular magnetization by passing electric current through the object;
CPU — circular magnetization by passing electric current through the auxiliary center conductor;
TSE — circular magnetization by passing current through the parts with the use of manual switch contacts;
DH — circular magnetization with the use of a toroidal winding;
The QI — induction circular magnetization;
N — pole magnetization;
PS — polar magnetization using solenoid;
PE — pole magnetizing using electromagnet;
PM — polar magnetization with the use of a permanent magnet;
MK — magnetization using the magnetic contact;
VP — magnetization in a rotating magnetic field;
To the combined magnetization;
PT — DC;
PR — AC;
IN the half-wave rectified current;
VD — rectified full-wave current;
W — rectified three-phase current;
And pulse current;
TP — intermittent current (current of break).
5 the Technical capabilities of magnetic particle inspection
5.1 the Magnetic particle method of nondestructive control based on the attraction of magnetic particles by the forces of inhomogeneous magnetic fields generated on defects in magnetized objects, with education in areas of defects in flat drawings in the form of clusters of magnetic particles. The presence and length of display of pictures recorded visually using optical instruments or automatic detection devices and image processing.
5.2 Objects of the IPC are a variety of semi-finished products, parts, components, subassemblies and products, welded, riveted and bolted joints, including those with the protective or protective and decorative coatings, including the objects in the design of aircraft, mechanisms, machines, equipment, means of transport and other equipment.
5.3 Magnetic particle inspection can detect surface and subsurface defects, such as discontinuity of material: cracks of different origin (szlifowanie, forging, stamping, hardening, fatigue, deformation, etching, etc.), flocs, sunsets, tears, volosovichi, bundles, weld defects (cracks, lack of penetration, slag, flux and oxide inclusions, undercuts), etc.
A precondition for the application of the IPC to identify defects is to have access to the test object to magnetize, processing, display materials, inspection and evaluation of inspection results.
5.4 Magnetic particle method allows to detect under appropriate conditions visually invisible and poorly visible surface defects with the following minimum sizes: disclosure of 0.001 mm; depth 0.01 mm; length of 0.5 mm and larger.
5.5 the results of the magnetic particle inspection method depends on the following factors:
— magnetic properties of material objects;
— the shape and size of the test objects.
— species the location and orientation of defects open to the surface;
— the accessibility of the control areas, especially in the case of control objects that are installed in the design of the product;
— surface roughness;
— the presence and level of surface hardening;
— thickness of non-magnetic coatings;
— magnetic field strength and its distribution on the surface of the test object;
— angle between direction of magnetizing field and to the planes of defects to be detected;
— the properties of the magnetic indicator;
— the method of its application to the object of control;
— intensity magnetic coagulation of the powder in the process of identifying defects;
— the method and conditions of registration display of drawings of defects to be detected.
These factors are taken into account when designing technology IPC objects.
5.6 Magnetic particle method can be used to control objects with a non-magnetic coating (layer of paint, lacquer, chromium, copper, cadmium, zinc, etc.). Objects with a nonmagnetic coating of a total thickness of 40−50 microns can be controlled without significantly reducing the incidence of defects.
5.7 If the IPC may reduce the incidence of defects:
plane which make an angle less than 30° with controlled surface or with the direction of magnetic flux;
— a subsurface;
— on the object’s surface with a roughness parameter of>10 microns;
— in the presence of surface deposits, corrosion products, slags, thermoosmosis.
5.8 Magnetic particle inspection applies to the indicator (neisserial) NDT methods. Method can not determine the length, depth and width of surface defects, subsurface defects size and depth.
5.9 Magnetic particle method can not be controlled parts, components and subassemblies:
— made of non-ferromagnetic steels, non-ferrous metals and alloys;
— on which surface area of the control not provided with the necessary approaches for magnetization, applying magnetic indicator and inspection;
— significant heterogeneity of magnetic material;
— welds done with a non-magnetic electrode.
5.10 Magnetic particle inspection is performed according to the instructions (methods) and operational (technological) cards. The recommended content of process instructions (methods) magnetic particle inspection of objects is given in Appendix A, and operating (process) card in Annex B.
5.11 the Volume control, as well as the types of unacceptable defects and their dimensions are set in the NTD of the industry or enterprise control objects.
5.12 Conduct magnetic particle inspection on the night shift is not recommended.
5.13 In NTD industry or enterprise to the control of the magnetic particle method it is recommended to use the symbols of the types and methods of magnetization and of the form of magnetizing current.
6 the Choice of instrument
6.1 depending on the goals and tasks of supervision, working conditions, and other factors while IPC objects can be used the following equipment:
— universal stationary detectors;
specialized stationary flaw detectors, including automated, designed for control of the same objects;
universal portable (portable) magnetic particle flaw detectors designed for control of different types of structural elements, parts, nodes and other objects as well as specialized portable flaw detectors;
— stationary or portable sources of light or UV radiation controlled surface;
— devices for measurement of magnetizing and demagnetizing magnetic field (tension or induction) with an error not exceeding 10%;
indicators of the magnetic field;
— devices for determining the kinematic or relative viscosity of magnetic suspensions (viscometers);
— instruments for measuring light levels and UV irradiance controlled surface;
— demagnetizing device;
— instruments for assessment of the level of demagnetization (if necessary, demagnetization of objects after test.);
— devices for quantifying the sensitivity of magnetic indicators and the concentration of the magnetic powder in suspension;
device for the controlled surface inspection and check defects: observation with optical instruments (magnifying glass, binocular stereoscopic microscopes, mirrors, endoscopes), television system as well as automated device discovery, registration, and image processing;
— control samples to evaluate the health of magnetic particle flaw detectors and magnetic indicators.
6.2 the composition of the magnetic particle flaw detectors (magnetizer), depending on their purpose and design may include the following functional units:
— power supply unit;
— software unit;
— block formation of the magnetizing current;
— magnetization (and demagnetization) of the device (three rings, solenoids, solenoids, flexible cables, Central terminals, switch contacts, permanent magnets);
system or unit of measure of the magnetizing current (magnetic field);
— or the system control unit operations control;
device for applying to the control of the magnetic indicator;
— instruments and apparatus for quality control of magnetic indicators;
— light sources or UV irradiation;
device for the inspection of controlled surface and record defects.
The demagnetizing device, a means of quality control of magnetic indicators, means of inspection of the controlled surface and defects recording can be made in the form of separate units, devices, or appliances.
In the shop lighting or UV irradiation in addition to the detectors installed at the specialized jobs (lookout cabin) inspection of objects with the aim of finding the indicator figures defects.
6.3 Requirements for magnetic particle flaw detectors and magnetizing devices meet the requirements of GOST R 53700. Requirements for specialized, including automated magnetic particle flaw detectors are installed in the NTD of the industry or enterprise.
Requirements for portable AC magnets, flexible cables, for switch contacts, sources of UV radiation and the viewing booths for the inspection of objects of control when using fluorescent magnetic indicators — according to GOST R 53700.
6.4 Magnetic particle flaw detectors is selected based on:
— item, the configuration and dimensions of the test objects.
— conditions of work (in the shop, in the outdoor area, the design of technical products, on the stocks, including the height, etc.) and availability of control areas;
— the required value of magnetizing current or magnetic field strength;
— use of the IPC;
— desired productivity;
— technical and economic possibilities of the enterprise.
6.5 To ensure high detectability of defects by the residual magnetization method with the use of solenoid, electromagnet, etc., it is recommended to use the power source or control current, to ensure when switched off, the reduction of the magnetizing current from the maximum value to zero in less than 5 MS.
6.6 Automated magnetic particle flaw detectors are used in workshop conditions with the aim of increasing the reliability of control and productivity, and reduce human influence on inspection results. Automated detectors should ensure that some or all basic and auxiliary operations of the IPC, including:
the magnetization of the test objects.
— preparation of the test object (degreasing, washing, drying, etc.);
— the application of the control zone of the magnetic indicator;
— search and detection of defects;
— the necessary movement of the object of control at work zones along the process flow, they rise and rotation in the process of technological operations, including the search of defects and their elimination from the last working area;
— excretion in the area of marriage or marking of objects with detected defects;
— positioning of cameras;
— the detuning from the influence of confounding factors;
— audible alarm in case of detection of defects;
— display of parameters and testing results on the computer screen or on the information Board;
— automatic processing of control results and their documentation on paper and electronic carriers;
— health check system and channels of the detector;
— demagnetization of objects which are not defects after inspection.
6.7 satellite System for search and detection of automated magnetic particle flaw detection should be based on the use of a variety of characteristics of the indicator figures defects and should be close to human visual analysis and perception of images. For the detection and identification of defects in these systems should be used 5−6 or more characteristics of defects selected from among the following:
— the location indicator figures defects on the surface of the test objects.
the direction of propagation of the lines of the drawings respect to the axis of the object, direction of processing, and the objects that were in operation, with respect to the direction of current workloads;
— the length of the lines of the drawings;
— configuration of the drawings, the bent and broken lines of the drawings;
— the width of the lines of the drawings;
— the similarity of the outlines of the long figures;
— sharpen or blur the outlines of the drawings;
— colour or brightness of a luminescence of the indicator.
— contrast patterns on the background of the defect-free surface;
— surface texture images;
— the microrelief of the surface in the locations of the drawings.
6.8 In automated flaw detectors shall be provided the automation of monitoring processing modes of the objects on each transaction individually and allows you to change these modes. Sections of the IPC, where such detectors, it is recommended to provide systems and devices, treatment and disposal of wastes and emissions, and the use of magnetic suspensions based on water with closed — loop systems. Automated detectors should create a comfortable conditions of work of radiographers.
6.9 In the operational documentation for magnetic particle flaw detectors needs to be specified:
— the possibility of controlling the ways of the residual magnetization and/or magnetic field applied;
— the ability to detect defects minimum size;
supply voltage and power consumption;
— weight and dimensions;
— the operational ranges of temperature, humidity and atmospheric pressure.
In the operational documentation on magnetic particle flaw detector with magnetizing device powered by a source of magnetizing current must also be given:
— maximum power consumption;
— view of the magnetizing current;
— the voltage and frequency of the magnetizing current;
— the maximum and minimum values of the magnetizing current;
— method of regulating the magnetizing current (stepped, smooth, the current is not adjustable).
When using intermittent mode of magnetization in the operational documentation must include:
the turn — on duration and the pause duration;
— maximum current at which the detector can operate continuously.
6.10 to test flaw detectors for detection of defects (after the manufacture or repair jobs of control) control samples used for IPC with natural or artificial defects. Examples of patterns are given in Appendix d and in GOST R ISO 9934−2.
When the magnetization of objects using the center conductor to verify magnetic particle flaw detectors can be used a sample of the type MO-4 (Appendix C) or type 1 according to GOST R ISO 9934−2.
7 selection of the magnetic indicator
7.1 as magnetic indicators magnetic particle with the applied control magnetic powders, suspensions, aerosols, air suspension and magnetoluminescence paste.
For the preparation of magnetic suspensions can be used in the magnetic concentrates or pastes are semi-finished products of magnetic suspension in the form of a grease of a mixture of ferromagnetic powder, of a suspension stabilizer, corrosion inhibitor, wetting agent, a viscous binder, and other components. Before use, the concentrate (paste) diluted in the dispersion medium.
Magnetoluminescence paste is solidified grease of a mixture of ferromagnetic powder, plasticizer and other auxiliary components in the dispersion medium on the basis of chlorinated rubber, cyclocarya, Nairit, or other polymer. Typically, they are used to detect defects in inaccessible places, e.g. on the walls of deep holes.
7.2 the Basis of magnetic indicators are powders of iron, Nickel, their oxides or ferrites. Depending on the roughness and color of the surface of the test object using magnetic powders having a natural color (black, red-brown) or painted — coloured (red, yellow or white, etc.) or luminescent.
The average particle size of the magnetic powder, designed for application in the dry way, should be no more than 200 microns, and the inspection method of the air suspension of the powder is not more than 10 µm. Depending on the goals and objectives control the size of powder can be different.
A maximum particle size of magnetic powders intended for use in suspensions, should be no more than 60 microns.
7.3 Magnetic indicator is selected based on:
— the required sensitivity of the IPC;
— the properties of the magnetic indicator;
— the type and location of defects open to the surface;
— color surface of the object of control and its roughness;
— conditions of work monitoring;
— desired productivity;
— technical and economic possibilities of the enterprise.
7.4 To complete the IPC should be applied powders of undamaged packages with an unexpired retention period. Powders having traces of corrosion, foreign material or tightly Packed clumps, regardless of the warranty period of storage to use and shouldn’t be allowed.
7.5 When using the magnetic powder in the slurry dispersion medium include the following: kerosene, liquid process oil, and mixtures thereof, water, and other liquids. If you do not use magnetic powders containing additives, or concentrates (pastes), the dispersion medium is added corrosion inhibitors, defoamers, wetting agents, stabilizers and other surfactants.
When using lyuminestsiruyushchikh powder dispersion medium of the slurry should not luminesce color, reduce the optical properties of the powder. Allowed luminescence of the dispersion medium of the slurry color, a contrast to the luminescence of the powder and to facilitate detection of the indicator figures defects.
7.6 recommended concentration of the magnetic powder in the suspension should be:
(25±5) g/l for color or black (aluminescent) powder;
(4±1) g/l for lyuminestsiruyushchikh.
When the control thread, fillets of small radius, under the control of SPP with the magnetic field equal to or greater than 100 A/cm and in other justified cases, the concentration of black or colored magnetic powder is reduced to 5−7 g/l In technically justified cases, set the other values of concentration of magnetic powder in suspension.
7.7 Kinematic viscosity of the dispersion medium of the slurry at the temperature control should not exceed 36·10m
/s (36 SST). At high slurry viscosity at which the viscous friction of the fluid above the force of attraction of magnetic particles to the defect, defect detection is impossible.
Viscosity of suspensions above 10·10m
/s (10 cSt) to engineering documentation for the control objects of a specific type must be indicated the time flow off of the main mass of magnetic suspension, after which let the inspection the controlled surface.
The viscosity of the dispersion medium of the slurry oil-based and oil-kerosene mixtures, it is recommended to measure during its preparation and in the process of using the frequency specified in the reference document on magnetic particle inspection. Instead of kinematic viscosity is allowed to measure the relative viscosity of the suspensions. Guidelines for determining the relative viscosity of the dispersion medium of the magnetic suspensions are given in Appendix D.
7.8 Magnetic slurry should wet the surface of the test object (not to gather in drops). It should not cause corrosion of the controlled surface.
7.9 Magnetic indicators should not be toxic and must not have an unpleasant odor.
7.10 Dry magnetic powder and magnetic suspension to avoid contamination should be stored in tightly closed containers made of non-magnetic materials (plastic, aluminum, etc.).
7.11 Water slurry must be protected from impurities (oil, kerosene, etc.), which cause coagulation of the powder and reduce the sensitivity of the suspension to the stray fields of defects.
7.12 multiple use of the concentration of magnetic suspension before carrying out the control shall be periodically checked using the device, for example, an electric meter, the concentration of the slurry. In technically justified cases, it is possible to determine the concentration of the slurry through sludge.
7.13 When using the dry magnetic powders and powders in suspension of their color, and luminescent powders — color and brightness of luminescence should be periodically visually evaluated in comparison with the standard samples.
7.14 Input and periodical control of magnetic indicators need to be conducted on their compliance with the SPECIFICATIONS. Tapping capacity magnetic indicators should be assessed quantitatively with the help of specialized electrical measuring instruments, and performance indicators, using control samples with defects to IPC. The procedure of input and periodic monitoring of magnetic indicators installed in the NTD of the industry or enterprise.
7.15 In the development of new magnetic indicators in addition to assessing tapping ability should be determined by the color of the magnetic powder, the particle size, magnetic permeability, coercive force, magnetic induction, thermal stability, coefficient of luminescence and luminescent stability, stability under use and storage, as well as the content of sulfur and Halogens — chlorine and fluorine. Some of the requirements for the testing of magnetic indicators is given in GOST R ISO 9934−2.
7.16 workplaces IPC quality magnetic indicators before each use check using the control samples with natural or artificial defects described in the application or a sample of type 1 and 2 according to GOST R ISO 9934−2.
7.17 Permitted to use magnetic indicators after the expiration date, subject to their compliance with the requirements of technical conditions.
8 the Choice of control samples
8.1 Control samples are parts or special products, made of a material of a certain composition, with predetermined geometric shape and dimensions, having a natural or artificial defect whose size is close to the sensitivity of the IPC process designed to verify magnetic particle flaw detectors and magnetic indicators.
Examples of control samples is given in Appendix b and in GOST R ISO 9934−2.
8.2 To verify magnetic particle flaw detector is mainly used control samples with artificial defects. Sample type for this purpose is selected based on:
— design flaw and methods of magnetization, for which it was designed;
— the nature of the defects detected on the scanned objects, their location and depth (surface or subsurface);
— direction of the magnetizing magnetic field generated in the magnetizing devices of the instrument, and the direction of propagation of the defects in the sample.
The performance of the detectors evaluated by identifying defects on the samples in all the ways of magnetization provided by the design of this flaw.
8.3 Control samples with embedded permanent magnets to verify magnetic particle flaw detectors is not used.
8.4 To verify that magnetic indicators mainly choose samples with cracks. However, for this purpose can also be used other samples of different types with natural or artificial defects, including embedded permanent magnets.
The efficiency of magnetic indicators evaluated by identifying defects in the samples with the methods of magnetization, which are calculated on each sample.
8.5 Samples, given in Appendix b, and the like, differing from the control objects are not allowed to use when assessing the possibility of using magnetic particle method of determining the modes of control of specific objects and evaluation of the detection of defects on them. In this case, should be used samples, the shape, size and material corresponding to the objects of control. The samples should be natural or artificial defects with sizes close to the minimum size of defects that are detected.
8.6 In assessing the possibility of using magnetic methods for the inspection of large structures is allowed to use the samples in the form of these objects, provided that when the magnetization of such samples, the distribution of magnetic flux in the area of possible location of finds defects would correspond to its distribution in the whole object.
9 the Choice of method of control
9.1 When magnetic particle inspection is used two ways of control:
— the method of residual magnetization (SLEEP);
— method applied field (SPP).
Control SLEEP and SPP under optimum modes allows to provide the same high sensitivity to defects.
9.2 in the SLEEP monitoring check objects first, magnetize, then after termination of the magnetization on the controlled surface is applied to the magnetic indicator and examine it to detect the indicator figures defects. The time interval between these operations must be no more than 3−4 h. the surface Inspection is carried out after draining of the main mass of the suspension.
9.3 Method of the residual magnetization mainly used in the control of objects made of magnetic materials, when the coercive force is more than 9.5 and 10.0 A/cm (12 e), in which the processes of technical magnetization and the magnetization reversal is carried out in strong magnetic fields.
9.4 in the control of SPP magnetic indicator is applied before the magnetization, or the magnetization process. When this indicator figures defects formed during magnetization. First stop the application of the indicator on the test object, then the magnetization. Inspection of the controlled surface is performed when the magnetization and (or) after cessation of magnetization and draining of the main mass of the suspension.
9.5 Method the applied field is usually used to monitor objects made of magnetic materials, i.e. materials with high magnetic permeability, low coercive force (less than 10 A/cm), low energy loss in remagnetization and can be magnetized and peremagnichivaniya in weak magnetic fields.
9.6 choose the IPC Method with the use of the curve is equal to the specific magnetic energy of the material is given in Appendix E. In those cases when it is determined that the object can be checked like a DREAM, and SPP, additionally take into account its shape and size, texture, material, the presence and thickness of the protective coating, demagnetizing factor, manufacturability and ease of performance, and the performance of the work under control one way or another.
9.7 In some cases, in applied field control the objects of hard magnetic steels, including:
— if you want to detect subsurface flaws at a depth of 0.01 mm (but usually less than 2 mm);
— check if the object has a non-removable non-magnetic coating thickness (layer of chrome, zinc, paint with a total thickness of 40−50 microns and more);
— when objects have a complex shape, big cross-section or a low elongation (in the case of a constant magnetic field, the ratio of length to equivalent diameter smaller than 5). therefore, they are difficult to magnetize to the required level of induction, to verify method of the residual magnetization;
— in the inspection of large objects in case of insufficient power of the flaw detector when the material objects could not magnetize to the level necessary for carrying out the control method of the residual magnetization;
— if you control small areas of large objects using DC electromagnets or permanent magnets.
9.8 Control SLEEP compared with the SPP has a number of advantages, which include:
— reducing the danger of local overheating of the material of the objects when magnetized by a current in places of their contact with discs kzu or manual switch contacts as the current is passed through objects for short periods (within 0,0015−2);
— minimal impact on measurement or indicator showing the devices for controlling objects in design equipment, mechanisms, machines, and similar products with such devices;
— under control of individual objects (before Assembly of components or parts, dismantled from construction products) there is a possibility of application of magnetic suspension in different ways: through irrigation or by immersing objects in a bath of slurry;
— when examining the individual controlled objects to detect defects there is a possibility of installation in any convenient position providing good coverage of the area of control and inspection with the naked eye or with the use of loupes, microscopes or other optical instruments;
— much less difficulties in deciphering the deposition of the magnetic powder as in the control of SLEEP powder, to a lesser extent settles at the risks, work hardening, in the areas of reduced cross section of the metal to rough surface treatment;
— better performance control.
10 Measures to ensure the operability of the controls according to their metrological support
10.1 To ensure the efficiency of controls and high reliability of its results at all stages of development and production of these means should be carried out metrological control, and during their operation — a complex of measures on maintenance.
10.2 In developing the design of the new magnetic particle flaw detector projects design and technological documentation for the manufacture of the instrument should be subject to metrological expertise to analyze and evaluate technical solutions for selection of measurement parameters, operations, and rules of measurement, the establishment of optimal requirements for measurement accuracy, the choice of methods and measuring instruments and provided that their metrological service.
Metrological examination of design and technological documentation shall be conducted in accordance with the recommendations in force in the Russian Federation [1].
10.3 In the development of design magnetic particle flaw detector shall be provided conditions for metrological service built-in measuring instruments, for example, systems for measuring magnetizing current, magnetic field strength and the other designed for use for its intended purpose, without retrieving it from the design flaw.
In the user manual of the instrument should be the method of service of such measuring instruments.
10.4 Develop methods of measurement must undergo metrological examination in accordance with the requirements of GOST R 8.563 and [2].
10.5 To save the flaw in good condition and prevent failure under operating conditions must be periodically performed preventive maintenance. Maintenance of flaw detection is carried out according to the regulations of the manual, or on a technical condition.
10.6 Preventive maintenance of detectors includes external inspection of the hull and electrical components to detect faults, corrosion, charring or mechanical damage to the insulation, cable breaks and other defects. When preventive maintenance is carried out as a cleaning equipment, including removal of moisture, dust, grease mechanical parts, adjustment and fine-tuning of individual elements, testing of switches and sockets to connect external devices (solenoids, flexible cables, illuminators and reflectors). In conclusion the service are checking functioning of all systems, including built-in control circuit efficiency of the flaw (if any).
Check operation and setting of controls in the original position should be performed in accordance with the manual of the instrument.
10.7 Magnetic particle flaw detectors after repair and periodically during the operation process are subject to verification and compliance with the main technical characteristics to meet specifications in accordance with the recommendations of the vendor of the flaw. Permitted deviation of measured parameters from the specification requirements should be no more than ±10%. It should also be assessed:
— parameters of the measuring systems included in the flaw detector;
— values and stability values specified magnetizing current or magnetic field strength and the parameters of the demagnetizing systems;
— the duration of the cycles, «current — break» detectors, which provide such mode of magnetization;
— the flaw, magnetizing objects with the use of solenoid, electromagnet, etc., the duration of the reduction of the magnetizing current from the maximum value to zero after it is turned off in accordance with 6.9;
— the flaw, which provide for the magnetization of the objects of the current pulses, the current pulse duration and pulse frequency in the mode of the applied magnetic field.
Additional parameters magnetic particle flaw detector, which needs to be monitored, and their frequency determines the developer of the instrument.
Permissible deviation of these parameters from the technical requirements should be no more than ±10%.
10.8 When the deviation of the ammeter (kiloampermetry), voltmeters and gauges of the magnetic field embedded in the system tester, technical requirements by more than ±10% is allowed to determine the correction values and the results of the measurements to clarify by introducing amendments.
10.9 Measuring devices used for magnetic particle control, including those intended to quantify the ability of detecting magnetic indicators, means of control of the illuminance and UV irradiance of the test objects, measuring of magnetic field intensity and other measuring instruments subject to metrological support in accordance with state or departmental rules and regulations: primary — in the factory and after repair, and periodically in the process of operation.
10.10 the Means of measurement not used in the sphere of distribution state metrological control and supervision, calibrated Metrology service enterprises or other metrological service is accredited to carry out calibration work [3].
The procedure of maintaining such means of measurement in operational condition should be determined by the manufacturers or consumers using the system calibration and certification of measuring instruments.
10.11 the Efficiency of magnetic particle flaw detectors and magnetic indicators before starting work subject to verification of defect detection in the control samples for IPC with natural or artificial defects are listed in Annex V or in GOST R ISO 9934−2.
11 preparations for the control
11.1 Preparation for conducting magnetic particle inspection include:
— preparation of objects for control;
— health check of the instrument;
— quality inspection of the magnetic indicator.
11.2 During the preparation of the objects to control with check surfaces and remove oil, grease, dust, scale, corrosion products, mill scale and other contaminants and also protective paint or protective coating, if the total coating thickness (including chemical and galvanic) is greater than 40 microns.
Allowed to control objects (parts, assemblies, welds, etc.) after oxidation, staining, or applying a non-magnetic metallic coatings (zinc, chromium, cadmium, copper, etc.), if the total coating thickness not exceeding 40 µm.
11.3 For removing contaminants and coatings from the surface of the object of control is used in washing with water and aqueous solutions of chemicals, washing by organic solvents, ultrasonic cleaning, electrochemical treatment, including the anode-base and cathode-anode-base and anode-ultrasonic machining, water jet machining and other methods. The purification method is selected based on the nature and physico-chemical properties of the contaminants or coatings.
11.4 Contamination and coatings from the surface of the test objects removed:
— traces of chemicals after the etching and the electrochemical polishing — washing in water;
abrasive and metal dust, traces of coolant on the basis of light oils and polishing pastes after machining and polishing objects and tools interoperable protection (emulsol, protective emulsion, light mineral oil) is rinsed with an aqueous solution of TMS, solvent, complex-solvent or kerosene;
— tools interoperable protection based on inhibited oils, oil-quenching medium, cooling lubricants based on industrial and cylinder oils by washing with an aqueous solution of TMS, followed by ultrasonic cleaning in the same environment;
— spontaneously not removed vitreous and ceramic coatings and metals used in the heating before forging, stamping, pressing and quenching, the slag after heat treatment, the traces of flux and slag on the surface of welded joints — etching, followed by ultrasonic cleaning or water-jet treatment;
— dense resinous and carbonaceous deposits, corrosion products, thick and durable carbon — chemical, electrochemical or abrasive waterjet machining;
— coatings — complex solvents, chemical washes, waterjet machining, anode-anode alkaline or ultrasonic treatment;
— electroplating — electrochemical or abrasive waterjet machining.
11.5 Surface with the remnants of the contamination cleaned by hand using a stiff bristle brushes, wooden or plastic scrapers, spatulas, and detergents. Apply the cloth, leaving after wiping the lint and threads, is not recommended.
11.6 If the IPC with the application of dry magnetic powder and slurry with an organic dispersion medium after the application of detergents and cleaning products, water-based controlled surface dried by wiping with a clean dry cloth, blowing with compressed air or by heating.
11.7 In cases where the period of time between the preparation of facilities for the control and execution of subsequent operations, MPK exceeds the time allowed for storing them without protection, after the application of detergents and cleaning products based on water, not having in its composition of corrosion inhibitors, for protection of objects that do not have galvanic or chemical coatings, apply interoperational anticorrosive protection.
If the IPC is used when the magnetic suspension is water-based, interoperable protection perform:
— with inhibited paper or a protective film;
— dip small objects in containers with silica gel or other desiccant.
— treatment of objects with an aqueous solution of sodium nitrite, sodium carbonate (soda ash) or other similar means;
— using a protective atmosphere or other method adopted by enterprise, which is not prejudicial to the wettability of the surface of objects of the control aqueous suspension.
The use of coolants and cutting fluids, protective coatings and inhibited oils in this case is not allowed.
If IPC is used magnetic suspension organic based, interoperable protection perform the processing of objects, cooling or lubricant-coolants, protective emulsion, a light low-viscosity mineral oil, inhibited with the help of paper or any other method adopted by enterprise, do not reduce wettability controlled surface magnetic suspension.
11.8 When using aqueous magnetic suspensions, containing the active wetting component controlled by the object’s surface previously degreased.
11.9 local control of bulky objects and contamination coating is removed from the controlled area and areas with a width of 10−15 mm around control zones.
11.10 When circular magnetization by passing current through the object or its portion of the installation area of the switch contacts or contact surfaces kzu purified from non-conductive coatings and sanded to bare metal.
11.11 Under the control of the welds cleaned of dirt, slag and other contaminants and coatings the surface of the weld and the HAZ of the base metal of a width equal to the width of the seam, but not less than 20 mm on both sides. Apply to clean surface of seams of a metal brush, washed down the weld bead to reduce its bulge is only allowed in cases if it is stipulated in technical requirements for welded connection.
11.12 When controlling objects with a dark surface, generally used fluorescent or colored magnetic powder. When using black magnetic powder on the dark-controlled surface pre-coated with the spray gun a smooth, thin layer of a contrasting coating (white or yellow paint or nitroemali) of a thickness not exceeding 20 microns.
11.13 If in the control zone or near it there are cavities, grooves, slots or holes, where the penetration of magnetic suspension are not permitted, they are closed with a thick grease or plugs. Grease lubrication also cover the elements of the objects that should not be in contact with a magnetic suspension or a powder.
11.14 the Need for demagnetizing the previously magnetized objects before conducting the IPC point in the technological documentation for the control objects of a particular type.
11.15 health Check flaw detector and magnetic quality of the indicator before carrying out the inspection is carried out using samples with defects specified in the application or in GOST R ISO 9934−2. The flaw detector and the indicator is considered suitable for use if the sample defects are detected, and the indicator figure corresponds to the defects recording (Appendix G).
11.16 If magnetic particle inspection is performed after welding or heat treatment details, start control is permitted only after cooling of the controlled object to the ambient temperature.
12 Technological operations and methods of magnetic particle inspection. The magnetization
12.1 Magnetic particle inspection includes the following technological operations:
— magnetization;
— the application of the magnetic indicator;
— controlled surface inspection and detection of defects;
— evaluation and presentation of results control;
— degaussing (if necessary);
— closing operation.
12.2 In the IPC apply the following types of magnetization:
circular;
— longitudinal (pole);
— induction circular;
— combined;
— in a rotating magnetic field;
— method of magnetic contact.
12.3, method and scheme of magnetization is chosen depending on the geometric shape and dimensions of the test object, the material and thickness of the nonmagnetic protective coating, and the type, location and orientation of defects subject to detection. The best condition for the detection of flaws perpendicular to the magnetizing direction of the magnetic field relative to the direction of expected defects.
12.4 Minimum and maximum values of intensity of the applied magnetic field is determined by the application And or by the formula:
| the minimum value | N min=15+1,1 N, |
(1) |
| maximum | N max=40+1,5 NS. | (2) |
Examples, methods and diagrams of magnetization of the objects is given in Appendix J.
12.5 allowed the reduction of the angle between the direction of the magnetic field and the plane of the defects and 30°. In this case, if the angle between the direction of the magnetic field and the plane of the defect is 60° or less to ensure detection of defects, the corresponding angle is 90°, the tension set of the magnetizing field needs to be increased by a factor
taking into account the angle
between the direction of the magnetic field and the plane of expected defects according to the ratio:
or
where is the magnetic field strength required to detect defects of this direction at an angle between the direction of the magnetic field and the plane of the defect of 90°.
The ratio of increase in specified magnetic field intensity depending on the angle between the direction of the magnetic field and the plane of the defects is equal to:
| The angle between the direction of the magnetic field and the plane of the defect | The ratio |
| 60° |
1,15 |
| 50° |
1,30 |
| 40° |
1,56 |
| 30° | Of 2.00 |
If the likely direction of expected defects is unknown, the material of the object magnetize in two or three mutually perpendicular directions, or use the combined magnetization.
12.6 When circular magnetization is the magnetic flux all the way takes place in the material of the inspected object. Circular magnetization is carried out by passing a current across the surface or throughout the volume of the material of the controlled object, either on his part or on the Central conductor (rod, cable) passing through the through hole in the object. It is recommended to place the rod along the axis of the hole. The magnetization may be performed simultaneously by multiple hollow objects, worn on the rod.
In circular magnetization, defects are found predominantly longitudinal orientation (extending along the direction of the magnetizing current) and radially directed defects in the end surfaces of the objects. Detection of transverse defects is not guaranteed.
12.7 circular magnetization in the control of internal surfaces of objects is carried out by passing current through inserted into the hole of the rod is covered with insulating material.
Longitudinal magnetization of these objects is performed with the use of a solenoid which is inserted into the internal cavity of the object.
12.8 the longitudinal (pole) magnetized by the magnetic flux of one part of the journey passes through the object material, the other on the air. On the object produces magnetic poles. Longitudinal magnetization is carried out using solenoids, the windings of a flexible cable, magnet or magnetizing device for permanent magnets.
When the longitudinal magnetization is predominantly detected defects of transverse orientation, i.e., extending perpendicular to the axis of the solenoids, the windings of the cable and lines connecting the pole pieces of the electromagnets or devices on permanent magnets. Detection of longitudinal defects are not guaranteed.
Permanent magnets can be part of portable flaw detectors and used for local control of objects, including structurally complex and bulky in the shop, field, stacker and other conditions.
12.9 circular induction magnetizing is carried out by excitation in the material object of the control electric current, a which the object is magnetized. The induced magnetization is used to detect circumferential defects located on the lateral external and internal surfaces of the test object.
12.10 When the magnetization of objects, apply the following types of electric current: pulse, DC, AC or three-phase, half-wave rectified or full-wave, rectified three phase, including the phase adjustment of the current. When magnetized by an alternating or pulsed current magnetized surface layer of the test object, which allows to detect only surface defects. When the magnetization constant or rectified current magnetized surface and subsurface layers, which allows to identify both surface and subsurface defects (to a depth of 2 mm).
12.11 the Combined magnetization is carried out by imposing on the object of control of two or more differently directed magnetic fields.
Under the combined magnetization are used:
variable sine wave, the rectified single or full-wave magnetic field, a constant magnetic field in combination with any variables;
— half-wave rectified magnetic field, shifted in phase by 120°.
12.12 the magnetization of the rotating magnetic field is a field of electric current excited in the test object. It is performed in the solenoid-type stator asynchronous motor. The magnetization rotating field is used for SLEEP monitoring objects with a large demagnetizing factor, with limited pads, objects of complex shape and/or non-conductive coatings.
12.13 the current Value when circular magnetization is determined depending on the required value of the tangential magnetic field on the controlled surface, and the shape and size of the cross section of the object of control. When you SLEEP monitoring current circular magnetization is calculated by the maximum diameter of the test object or at the most remote areas from the axis of the check object. For inspecting objects having a cross-section of a simple form, and large-sized objects, the current value is determined using the following formulas, the formulas given in Appendix W, or direct measurements of the strength of the magnetizing magnetic field.
12.14 the Estimated current value in amperes for circular magnetization by passing current across the surface or throughout the volume of the material of the test objects of relatively simple cross section is determined by the formula:
— for objects with a cross section in the form of a circle with a diameter (cm):
where - specified magnetic field strength, A/cm
For objects, the cross section of which is in the control zone differs from a circle, diameter take the greatest cross-sectional dimension. With complex cross-sectional shape of the object as
taking the equivalent diameter, which is calculated by the relation:
where perimeter of the cross section object in the control zone, see
Then
With complex cross-sectional shape of the object as you can also take the equivalent diameter, calculated considering the cross sectional area:
where is the cross-sectional area in the control zone, cm
.
12.15 For a bar of rectangular cross section with width and thickness
(cm) of the magnetizing current when circular magnetization is determined by one of the following ratios:
where - specified magnetic field strength, A/cm
Calculation of current for objects having a shape similar to one of the above, is held by the same formulas.
12.16 For objects of complex shape and the strength of the current circular magnetization in the first approximation, is determined by the same formula, and then clarify experimentally by adjusting the value of the current providing a given magnetic field strength.
12.17 circular magnetization of a part of the controlled object is carried out by passing through it an electric current through two contacts. The current strength in amperes passing through the object, when magnetizing a variable, a constant and the rectified currents is determined by the formulas given in Appendix J. the Largest current transmitted through the controlled object through the contacts, as a rule, is not more than 1500−1800 A.
12.18 the magnetization of the objects of the ring form with the control to detect defects developing in radial planes or located on their side (butt), inner and outer surfaces, is performed using a toroidal winding. The strength of the magnetizing current is determined by the formulas given in Annex J.
12.19 induction magnetization parameters of current and magnetic field in the magnetizing device is selected so that the object material was excited with an electric current, a which the object is magnetized. The current value is determined using one of the formulas (3) to (8).
12.20 When the longitudinal magnetization of the objects using a solenoid or winding of the flexible cable, the magnetizing current is determined by the formula:
where - the length of the solenoid coil or cable, cm;
- the required magnetic field strength, A/cm;
— number of turns of the solenoid (coil);
- the coefficient determined according to the following ratios of the radius R and the length of the solenoid or the coil:
| The ratio between radius and length of the solenoid (coil flexible cable) |
The value of the coefficient |
| R=(1/6)L |
2,03 |
| R=(1/5)L |
2,04 |
| R=(¼)L |
Of 2.06 |
| R=(1/3)L |
2,11 |
| R=(½)L |
2,24 |
| R=L |
Of 2.83 |
| R=2L |
4,47 |
| R=3L |
6,33 |
| R=4L |
8,24 |
| R=5L | 10,20 |
When you turn on the solenoid containing the object, the magnetic field will be slightly different from the calculated. But the difference for MPI insignificant.
12.21 sequential longitudinal magnetization of the object, and then the intermediate circular field demagnetization is not carried out if the residual magnetism has no effect on subsequent operations control.
12.22 Under the control of the SLEEP mode of magnetization of objects (the value of the magnetizing current or magnetic field strength) are selected so that the field strength was close technical magnetic saturation of the material. In justified cases it is possible to use a smaller field of tension.
12.23 Under the control of SPP values of the tangential and normal
components of the intensity vector of the magnetic field on the controlled surface must satisfy the condition:
The value is selected in accordance with the recommendations given in Appendix I.
12.24 in the application of SPP for objects that have different parts differ greatly from each other in the cross section, the control should be carried out in two or more techniques, choosing in each case, the current circular magnetization, respectively, the size (diameter) of the object in controlled areas.
12.25 for inspecting objects with a large demagnetizing factor, having a ratio of length to square root of cross sectional area (or maximum cross-sectional dimension) of less than 5, when the longitudinal magnetization in open circuit are the objects of control in the chain locating end surfaces to each other or use extension bits, or using an alternating magnetizing current with a frequency of 50 Hz and pulse current.
The contact area between the parts, are composed in the chain must be at least 1/3 the area of their end surfaces.
12.26 To reduce the likelihood of burn marks and local heating of the magnetizing devices and contact locations of objects in the control of SPP, it is recommended to apply intermittent magnetization, at which the current through the conductors of the magnetizing device is passed over (0,1−3,0) seconds with intervals up to 5 s.
12.27 In case of impossibility of a simultaneous magnetization of the entire object (for example, for inspecting objects of large sizes or complex forms) magnetized with the subsequent execution of other control operations should be carried out on individual plots. For this purpose, as a rule, use the external magnetizing means: remote switch contacts, the side electromagnets, devices based on permanent magnets, the coils of the flexible cable is imposed on the magnetized areas of the site, split solenoids and other means.
12.28 the magnetization of the material of the controlled object is the maximum (peak) value of current. But in the systems measurement of magnetizing current can be used ammeter, which is depending on principle of operation and calibration in the manufacture can determine the RMS (effective, effective), average over half period or the amplitude (peak) current value. Most of the scales of ammeters will graduate in the current values of the current. To monitor the magnetization process object, the current value is calculated according to the formulas, recalculate based on the type of ammeter used and the type of magnetizing current.
12.29 Recalculate current perform by the relation:
where is the value of the magnetizing current, shown a measuring instrument — ammeter;
— coefficient of proportionality, depending on the type of magnetizing current;
— calculated the required peak value of current.
12.30 When used in the flaw detector ammeter that determines the root mean square (RMS, effective) value of the current coefficient of proportionality equal to:
| View of the magnetizing current | The value of the coefficient |
| AC sinusoidal |
0,707 |
| The rectified half-wave |
0,500 |
| The rectified full-wave |
0,707 |
| Three-phase half-cycle | 0,840 |
When used in the flaw detector of the ammeter, which determines the average current, the proportionality factor is equal to:
| View of the magnetizing current |
The value of the coefficient |
| The rectified half-wave |
0,318 |
| The rectified full-wave |
0,637 |
| Three-phase half-wave |
0,826 |
| Three-phase full-wave | 0,955 |
12.31 the Value of the magnetizing current as in the circular and longitudinal (solenoids, electromagnets) and other methods of magnetization is allowed to determine and/or verify experimentally the following ways:
— to identify natural or artificial defects in the control samples, which is a check of the objects with cracks of minimum size, located in the checked zones, or to identify artificial defects in these samples — the control objects rejected for any other parameters;
— establishment of the preset value of the tangential magnetic field on check sites in control areas, as measured with instruments that measure the magnetic field. Thus, if you are monitoring SPP shall take into account the ratio of normal and tangential components of the field according to the 12.25. In the measurement of the magnetic field sensors of the devices must be placed directly on the surface of the object of control.
The use of control samples in the form of plates, rods, disks and other samples that differ from the objects of control, with cracks and artificial defects of minimum size, to determine the modes of magnetization of the specific control objects is not allowed.
12.32 the Mode of magnetization of test objects with the help of instruments and devices for measuring electric current or magnetic field with the measurement error not more than ±10%.
12.33 When the magnetization of the controlled magnetic field strength (the value of the magnetizing current) should be maintained within ±10% of assigned values.
13 the Application of a magnetic indicator on the control objects
13.1 When magnetic control magnetic indicator is applied to the surface of objects in a dry form, in the form of magnetic suspension or magnetoluminescence paste.
13.2 dry magnetic powder is applied on the controlled surface by spraying by means of a rubber pear, pulverizers, oscillating sieves, etc. or by setting the forming of the air suspension. The powder is applied evenly, without the formation on the surface of darker (enriched) or lighter (depleted powder).
Air suspension is used in the control of sensitivity in detecting subsurface defects and defects under a layer of non-magnetic coating thickness from 80 to 200 microns.
13.3 Magnetic suspension is applied on the controlled surface irrigation, spraying, or by immersion for 1−2 minutes small objects in a bath of well-mixed suspension. Watering and spraying of slurries should be carried out at low pressure jets so as not to remove magnetic powder accumulated on defects. In all cases, including after removal from the bath, it is recommended to provide the conditions for draining the magnetic suspension with controlled surface that it does not stagnate in some places — recesses the «pocket», between the ribs, etc.
When monitoring a small local area of the surface of the object of control, the suspension can be applied by brush.
13.4 When applying magnetic powder to the test object by spraying from an aerosol container holding it vertically at a distance of 250−300 mm from the controlled surface. The spray nozzle of the spray head is directed toward the area of control. To the spray head is short (within seconds) press the index finger and blow the powder. The direction of the spray jet should be approximately normal to the monitored surface or set the normal angle of 30−40°. To direct the jet tangentially to the controlled surface is not allowed because it leads to the removal of the formed indicator figures defects. If the control zone is greater than the diameter of the spray jet, spray jet to be moved along the test object to cover the area of control.
13.5 in the control of SPP suspension start to do before enabling the magnetizing current in the magnetizing device and finish it before the magnetizing field is turned off. The current in the magnetizing device shut down after draining of the main mass of the slurry from the surface of the object. Surface inspection is carried out in the magnetization and/or after switching off the current in the magnetizing device.
13.6 in the control of SLEEP magnetic indicator is applied on a controlled surface after removal of the magnetizing field (after turning off the magnetizing current in the device), but not later than 3−4 hours after magnetization (in the absence of touch of the magnetized parts with other parts during storage). Inspection of the controlled surface is carried out after draining of excess slurry.
13.7 On a vertical surface and on the surface, is located above the head, the slurry was applied from an aerosol container, or using plastic containers with capacity from 200 to 500 ml, in a tube which is inserted tube with a diameter of 5…6 mm.
13.8 Magnetoluminescence paste is prepared for use and applied to the objects of control according to the supplier’s recommendations.
14 Inspection of controlled surfaces and detection of defects. Assessment and registration of testing results
The length of the flat drawings of defects to be detected and their coordinates on the surface of the inspected object is determined using rulers, squares, calipers, made of non-magnetic materials, measuring scales of observation of optical instruments (magnifiers, microscopes, endoscopes) and other means of measuring linear dimensions.
14.1 When magnetic particle control defects detect and evaluate the presence of controlled surface display of a pattern of visible deposition of the magnetic powder, replayed repeatedly after each new application of magnetic suspension or powder.
14.2 technical drawings, formed on the defects, such as discontinuity of material, have the following characteristics:
planar defects (cracks, delamination, neoplasene, etc.) are manifested in the form of elongated generally thin flat drawings in the form of rolls of magnetic powder;
volume defects (pores, voids, and inclusions) form a round flat drawings;
— subsurface defects usually give fuzzy the settling of the powder.
14.3 For the detection of indicator figures defects the inspection of controlled objects surface is carried out visually or using automated detection devices and image processing.
14.4 using magnetic suspension inspection is performed after draining the main supply with a controlled surface area of the object.
14.5 During the inspection take measures to prevent Erasure of the magnetic powder cylinders with defects. In cases of attrition of deposits of the powder slurry was applied again. In the case of formation of a fuzzy indicator of the drawings, a second IPC.
14.6 visual inspection of objects can be applied in optical devices: the magnifying glass 2−7-fold increase, while control of small objects — a binocular stereoscopic microscope or other means.
Examination of the internal cavities of objects is performed using special probes, endoscopes, turning mirrors and other viewing devices made from non-magnetic materials.
14.7 Illumination controlled surface objects when using ferrous and non-ferrous aluminoceramic magnetic powders and suspensions based on them should be at least 1000−1500 Lux or more depending on the desired sensitivity to defects and optical properties of the surface of the test objects [4]. Illumination controlled by the light meter once a month, unless otherwise set industry norms.
14.8 At the fixed workplaces inspection of the objects should be used only combined lighting (General, together with the local). As a rule, should be used discharge lamps: for General lighting — type LB, LHB, IPF, for local — type LBCT, LDTS, LDTS UV. For local lighting allowed the use of incandescent bulbs, but only in the breast or frosted bulb. Can be used halogen lamps. But xenon should not be used. To avoid the appearance of glare on the polished objects of control dampened magnetic suspension, the jobs of inspection lamps is equipped with a non-transparent reflectors or diffusers so that the light segments and rays reflected from objects of control, do not fall in the field of worker. Local lighting of workplaces must be equipped with dimmers.
14.9 At the fixed workplaces of the inspection objects in the form of a table material and the color coating of its surface chosen to reduce the luminance contrasts in the field of view of the operator, to accelerate preadaptation with the alternation of observation of the test object and the background, to ensure the stability of the contrast sensitivity of the eye, and to prevent glare of light reflected from coating. For example, when viewed from the ground control objects and other objects with a light surface working surface of table cover non-shiny light green, light blue or greenish-blue plastic.
During the inspection of the objects controlled by using lyuminestsiruyushchikh magnetic indicator, working table surface must dissipate or absorb the ultraviolet rays.
14.10 Inspection of objects of control, the treated suspension of fluorescent magnetic powder, is carried out under ultraviolet irradiation. The level of irradiance controlled surface ultraviolet radiation should be not less than 2,000 µw/cm. The wavelength of UV radiation should be in the range of 315 to 400 nm with the emission maximum approximately 365 nm. The illumination area of the control visible light should not exceed 20 Lux.
UV irradiance monitor ultraviolet radiometer, or other measure of intensity of ultraviolet radiation once a month, unless otherwise set industry norms.
14.11 in the analysis and interpretation of the indicator figures defects distinguish deposition of the magnetic powder on the real defects from the false depositions. In the absence of defects in the deposition of the magnetic powder may be observed in the field:
— abrupt transitions from one section of the controlled object to another;
— a sharp local change in the magnetic properties of the metal (for example, along the boundary of the heat affected zone or the boundary of the «weld metal — base metal»), etc.;
— touch magnetized object to any ferromagnetic object (screwdriver, another part, etc.);
— location risks, scratches and rough surface treatment;
— boundary work-hardened surface;
group of small nicks;
location poloschatosti carbide of the metal;
— the location of the boundaries of the unstripped welded seams and boundaries of welds made of austenitic electrodes.
Typically, these locations formed a blurred, fuzzy deposition of the magnetic powder. To determine the reasons for the deposition of the magnetic powder in such cases, assess the design features of the object in the area, inspecting the cleaned surface using an optical means, re-perform magnetic particle inspection or control by another method.
14.12 section of the examination object, it is advisable to ensure that the defective control objects with defects and defectograms made in accordance with Annex G.
14.13 In order to enhance quality control it is advisable through each hour exam controlled surface, including when viewed on a computer screen, to make a break for 10−15 min.
14.14 inspection Results were judged in accordance with the standards provided for documentation on the manufacture, repair, reconstruction or operation of control objects.
Quality control objects are allowed to rate how flat drawings and the real nature of the detected defects, the size, number and distribution on the surface of objects.
14.15 inspection Results are recorded in the log, Protocol, route map, or other document. The record set in the NTD of the industry or enterprise to monitor objects of a specific type. Registration of the detected defects is performed by description, schematic drawing, photography, fixation using transparent adhesive tape, transparent varnish, the hardening resin, a magnetic tape, a video, or reading automated defect detection and fixing in the computer memory.
14.16 If necessary, the objects that are passed through IPC, they can be subjected marking: buggy — red paint in the form of lines, dots, or other marks; fit — white, blue or green paint, or drawing the letter «M» stamping, inlay, etching, by laser or other means that do not violate the strength properties of control objects.
15, the Demagnetization of control objects
15.1 testing Objects, which were carried out magnetic particle inspection must be degaussed:
— if their magnetization causes of error in readings, impairs the efficiency of equipment or sensors installed in a workpiece;
if the magnetization in the conditions of the objects may cause the accumulation of the products of wear in the movable joint;
— if the residual magnetization having a negative impact on subsequent technological operations to manufacture or repair products, as well as in other cases.
Subject to demagnetization, for example, shafts, wheels, gear reducers.
15.2 the Demagnetization is carried out by exposing the object, the alternating magnetic field decreasing to zero amplitude. For this purpose, stationary or portable, solenoids and electromagnets, and devices (e.g., detectors), allowing the object monitoring the current necessary to generate the required demagnetizing field.
15.3 Method of demagnetizing objects of a specific type installed in the NTD of the industry or enterprise to control these objects. Depending on the shape and size of objects demagnetization can be performed in the following ways:
— promotion of the object of control via a solenoid, powered by alternating current or direct current of changing polarity, and removing him to a distance where the magnetic field of the solenoid is equal to the intensity of the background. For example, for the stationary solenoids, this distance shall not be less than 0.7 m;
— reduction to zero of the current in the solenoid AC inserted in it wasmagnificent object. If the length of the object is greater than the length of the solenoid, the demagnetization is carried out on sites;
removal of an object from the solenoid (or electromagnet from the object), powered by alternating current or by direct current with periodically changing polarity;
— reduction to zero of the alternating current in the electromagnet in megapolises space which is razminochnye the object or the site;
— effects on the object of control is decreasing of bipolar pulsed magnetic fields;
— reduction to zero of the amplitude of the alternating current was passed through the test object, its parts, cable or rod passed through the hole in the object;
impact on the test object by a magnetic field directed counter to the magnetic field of the magnetized object. The tension of the demagnetizing field should be chosen experimentally so that after shutdown the residual induction of the object was close to zero (applies only for objects with simple shapes).
When using the AC demagnetized surface layer of the object not exceeding the depth of penetration of fields of the given frequency in the material of the object.
Allowed the use of other effective methods of demagnetization.
15.4 Plot structure or object can be directly demagnetize after inspection in applied field (SPP), if there is a flaw, provided with a device for degaussing. When you turn off this flaw or with a special switch the operating mode to the degaussing is a smooth decreasing alternating demagnetizing current.
15.5 After demagnetization level of residual magnetization is controlled by the objects must not exceed 5 A/cm, if the regulations do not set other field values, called the residual magnetization. The quality of demagnetization is controlled using the magnetometer, gradientometry magnetic field or other means. Method validation of residual magnetization of objects of a specific type installed in the NTD of the industry or enterprise to control these objects.
16 Final operations
16.1 When using magnetic water to form a suspension control projects that do not have galvanic or chemical coatings, the ones that are suitable on which to run subsequent operations to manufacture or repair should be interoperational anticorrosive protection in cases, if the suspension is missing the corrosion inhibitors, and the time to perform further operations exceeds the time allowed for storing them without protection.
For this object after demagnetization washed with water, wipe dry with a clean cloth and perform anticorrosive protection by means of cooling or lubricating liquids, aqueous solutions of corrosion inhibitors, inhibited paper, protective atmospheres or emulsions, oils, temporary protective coatings or other means approved by the company.
16.2 a Thick grease covering the holes, grooves, cracks, and other structural elements of the objects, remove with a rag, rinsing with solvent or kerosene, or other means.
16.3 With objects that are controlled with the use of contrast dyes and recognized fit, the paint is removed by means of complex solvent nitrokrasok and nitrocellulose or acetone.
16.4 To fit the objects on which the control was removed the protective or protective-decorative coating, the process of restoring it.
16.5 After control of the magnetizing device is wiped dry with a clean cloth from the tracks of the magnetic powder and suspension.
16.6 On the site of the IPC turn off the detector. Clean the flaw detector of traces of a magnetic powder and a suspension. Turn off the ventilation. Remove the plugs of all devices from sockets. Turn off the switches and push-button contactors. Turn off power to the network control site.
16.7 in the control of objects outside of the plot of the IPC turn off portable flaw detector, disconnect it from the network and transferred to the transport position. Removed from the control facilities and rags.
17 security Requirements
17.1 To conduct magnetic particle inspection allowed the radiographers have undergone training and instruction on occupational safety according to GOST
17.2 due To the fact that IPC is accompanied by a significant prolonged eye strain, persons admitted to their implementation, must undergo mandatory preliminary and periodic medical examinations.
17.3 the Radiographers are constantly engaged in the inspection of objects on the site of the IPC, to work overtime should not be involved.
17.4 In organizing and carrying out the IPC experts have rukovodstvuetsya 12.1.001, GOST
17.5 General safety requirements to technological process of the IPC in the premises, location of equipment and workplace control — according to GOST
17.6 For safe execution of work location and organization of workplaces on the part of the control, position of controls production equipment must meet the requirements of GOST and GOST 12.2.061
17.7 Design of production equipment must comply with the General safety requirements GOST 12.2.003 and General ergonomic requirements GOST
17.8 Design of magnetizing and demagnetizing devices, illuminators and UV-irradiators, as well as modes of their use in the IPC should ensure that at an ambient temperature of 25 °C the temperature of the surfaces, which can touch the radiographers in the course of work (flexible cables, magnetizing terminals, switches, handles solenoids, lighting, UV-irradiators, etc.), not more than 40 °C.
17.9 noise Level at working places of the IPC should be no higher than the standards set for production enterprises in accordance with GOST 12.1.003, and should be no more than 80 dBA.
17.10 For the inspection of objects in ultraviolet rays when magnetoluminescence control to be an isolated room or enclosure, to contain:
— working place for inspection of the test objects equipped with a UV irradiator;
— racks, Bartovice or truck to accommodate and check the rejected objects;
— fixtures with incandescent lamps or discharge lamps fluorescent light creates a background light of 10−20 Lux;
— air inlet and exhaust ventilation to remove vapors dispersed medium, magnetic suspension, ozone, nitrogen oxides and ionized air generated during operation of the UV irradiator.
During the work in field and workshop conditions allowed to explore the objects outside cabins subject to requirements for the illumination and UV irradiance.
17.11 In cases where when the magnetization and demagnetization of objects on the magnetic particle flaw detector magnetic field strength exceeds the norms established by applicable sanitary and epidemiological rules, when prolonged control controls stationary magnetic particle flaw detector should be put in the area where the magnetic field does not exceed the norms.
17.12 Production sites the IPC is massive and bulky items need to be equipped with lifting and transport mechanisms and rotary devices in accordance with GOST
17.13 Design of lamps used in areas of the IPC must meet safety requirements according to GOST
17.14 In the working zone of production areas of the IPC should be observed the optimal parameters of microclimatic conditions. Requirements for permissible content of harmful substances in the air of working zones, the temperature, relative humidity and air velocity in the working area of the areas of control — according to GOST
17.15 If necessary, to create permanent jobs, in working and service areas of premises meteorological conditions and purity of the air environment, the relevant applicable health standards, the IPC should be equipped with local supply and exhaust mechanical ventilation. General requirements to system of ventilation, air-conditioning and air heating sections of the IPC — the graveyard
17.16 When working with magnetic suspension on an organic basis and with dry magnetic powder, including its suspension in the air, the running must be in the flow of clean air.
17.17 in the control of objects in the design of technical products with a limited working volume in the control zone should be fed fresh air by a fan or other device.
17.18 When applied to objects control-contrast coatings must comply with safety requirements according to GOST
17.19 connecting the detectors to the AC outlet is carried out through specially equipped posts. In the absence on a workplace outlet connection of the instrument to the mains must be performed by the qualified electricians.
At breaks in work, even briefly, the instrument with electric power should be switched off.
17.20 Stationary and mobile detectors, the housings of illuminators, UV irradiators, portable lamps, spray chambers, fume hoods, and ventilation ducts, nozzles, tips, hoses, compressed air systems and other equipment of the area of the IPC must be earthed or zeroed in accordance with GOST
The fixed detectors shall be provided rubber mats or outdoor wood lattice.
17.21 the flaw ensured system operability testing, during testing and also during the magnetization and demagnetization of objects do not work control buttons modes of magnetization and demagnetization, as well as to attach or detach the magnetizing device of the flaw detector.
17.22 in the control of objects outside of the site IPC workstation running the control must be removed from the welding positions and is protected from radiant energy of the welding arc. Portable (portable) magnetic particle flaw detector before turning on must be earthed with a copper wire at least 2.5 mm.
17.23 When circular magnetization by passing current through the object part by using three rings or through switch contacts or the auxiliary conductor is placed in a through hole in the object, and when the longitudinal magnetization in the side of the solenoid should turn on and off an electric current only if a reliable electrical contact plates, three rings, switch contacts with the object, an auxiliary conductor or contact plate of the solenoid. All the electrical contacts must not have stains, traces of oil or fuel.
17.24 When the magnetization of objects you should use protective screens or guards according to GOST 12.4.023 or other personal protective equipment eyes and face according to GOST 12.4.238 to protect from the possible penetration of small particles of products of arcing.
17.25 When working on the flaw never touch uninsulated live parts, regardless of the voltage across them.
When the magnetization of objects by passing an electric current is not allowed to touch the magnetized objects or their parts.
17.26 When the magnetization of objects using a solenoid at the moment of magnetization is not allowed to hold hands magnetized objects placed in the solenoid. First, put the object into the solenoid and then turn the electric current.
17.27 Under the control of SPP objects in magnetic field:
— permanent — 120 A/cm;
— periodic with frequency of 50 Hz 64 A/cm,
inspection of the controlled object to the search of indicator figures defects can be performed only after switching off the magnetizing field.
17.28 When applying the magnetic suspension of objects by immersion, use tongs, holders, nets or other devices made of non-magnetic materials so as to avoid contact of skin with the slurry.
17.29 in the control of objects using aerosols with a magnetic powder or suspension of the aerosol jet is not allowed to send on an open flame and very hot objects. When working protect eyes, mouth and hands from direct exposure to aerosol spray.
Aerosol containers should be protected from bumps and drops. They should be kept away from heaters, do not expose to direct sunlight and temperatures over 50 °C. the First sign of danger depressurization of the tanks, their swelling.
Aerosol containers are under pressure. Therefore, never open the valve or disassemble the aerosol container, if it has a contents, to the full bleed of pressure through the valve. Not allowed to destroy the used cylinders burning.
17.30 When the IPC staff should be in uniforms. Must apply personal protective equipment (coat, oil-resistant rubber gloves, such as latex, armlets, etc.) in accordance with GOST 12.4.011 and GOST
17.31 For respiratory protection when working during the application of dry magnetic powder on the test object, including a suspension of powder in the air, must use respirators and eye protection — safety glasses. Respirators must be fabricated to have a constant supply of tampons (inserts). Clear the premises of trace powder should be performed with a vacuum cleaner.
17.32 During the inspection of objects of control are not allowed to use lights, protecting eyes from the blinding action of the light source.
17.33 When working with UV irradiators should be used personal protective equipment — gowns with long sleeves and gloves of the dark aluminstroy cotton fabric. Stationary and mobile UV irradiators shall be equipped with a built-in or separate devices that protect the face and eyes of the operator from the effects of UV radiation. As a protective material absorbing UV radiation, can be applied polyamide film type PM grade A with a minimum thickness of 30 microns or other material with similar optical density and the spectral characteristic of the transmission. For workplace inspections of the control surface of the working table should not luminesce. Reflectance UV-radiation of this surface should not be more than 0.2.
17.34 equipment equipment built-in devices protecting the eyes of the operator from the harmful effects of UV radiation and in the presence of the reflected UV radiation during the inspection of the controlled surface in conditions of darkening under UV radiation to protect your eyes you should use protective glasses with filters of colored optical glass ZHS-4 according to GOST 9411 thickness not less than 2 mm.
17.35 In the case of performing control on top, inside technical devices (machines) and in cramped conditions specialists in control, must undergo additional safety training according to the regulations prevailing in the enterprise. Work at height, inside the apparatus must be performed by a team consisting of at least two or three people, depending on the degree of danger.
17.36 Prohibited from working on unstable structures and in places where it may damage power supply wiring flaw detection.
17.37 in contact With magnetic powder, slurry, or other non-destructive testing reference material on unprotected skin, you should rinse the contaminated skin area with warm water and soap. Apply for washing the skin, kerosene, acetone or other solvents is strictly prohibited.
17.38 meal in the room area, the IPC is prohibited.
17.39 During the placement, storage, transportation and use of welding and auxiliary materials, waste production and close control, the requirements for fire protection in accordance with GOST
17.40 When IPC objects using magnetic suspension organic based:
— not allowed to use the outdoor heaters, Smoking, use of instruments, operation of which is associated with the spark event;
to prevent sparking is not allowed to impact the steel control objects. At the opening of the container with non-destructive testing materials do not use tools that give when you strike a spark;
— if the inspection of tanks with stock or a customer support supplies on an organic basis, with the presence of these materials or their vapours in the bath, and when ventilation is disabled on the site is prohibited to carry out welding work;
— during the inspection of objects it is prohibited to use a nylon brush and brush as well as cloth, synthetic, silk and wool fabric in connection with the possibility of occurrence of static electricity by friction them with objects and, consequently, sparking.
17.41 In case of fire the magnetic suspension on an organic basis should be provided for its suppression (after de-energization of electrical installations) using water mist, foam, chemical or mechanical air-from fixed installations or fire extinguishers, carbon dioxide or mixtures of ethyl bromide and liquid carbon dioxide.
17.42 in the control of SPP with a circular magnetization is not allowed to apply slurry on an organic basis with a flash point of the dispersion medium below 50 °C.
17.43 At the site of the IPC is not permitted to encumber any of the passages, outlets and workplaces and accesses to firefighting equipment, for buttons, on and off the ventilation and circuit breakers.
17.44 Waste production in the form of spent welding materials are subject to recycling, regeneration, removal in established collections or destroyed.
17.45 to protect the environment from contaminants in industrial environments must be installed in the control over observance of maximum permissible emissions into the atmosphere in accordance with GOST
Annex a (informative). The recommended content of process instructions (methods) magnetic particle inspection of objects, components, assemblies and subassemblies of technical products
Appendix A
(reference)
A. 1 sections of the instructions (procedure)
A. 1.1 Introduction (or General).
A. 1.2 Requirements safety and ergonomic requirements.
A. 1.3 requirements for the level of training and level of certification of the experts performing the IPC.
A. 1.4 the test Object and feature finds (detectable) defects.
A. 1.5 Applied flaw detector and other equipment and supplies. Type used magnetic indicator and other welding materials.
A. 1.6 Order of preparing the property for the inspection.
A. 1.7 health Check, magnetic particle flaw detector and magnetic indicator.
A. 1.8 Execution control.
A. 1.9 interpreting the results of the monitoring and evaluation of the condition of object of control.
A. 1.10 Procedure in case of detection of defects.
A. 1.11 Registration of testing results, documentation.
A. 1.12 Final operations.
A. 1.13 App.
A. 2 the Main content sections
A. 2.1 Introduction (or General)
The introduction should contain the following information:
a) purpose and scope instructions (methods) [place control in the technological route of manufacturing or repairing products after you run any of the operations shall be controlled (when operating, acceptance inspection, etc.), with a target inspections, performing routine maintenance, with control and acceptance tests of equipment, etc.];
b) information about the place where control is running (shop, land, stocks, location of equipment etc.);
C) in the case of monitoring the operation conditions of the equipment — the frequency of the control;
g) date of introduction instructions (methods) in action, its validity period;
d) basis of preparation of instruction (methods).
e) the control outside of the shop — climatic constraints for the control (if any).
A. 2.2 Requirements safety and ergonomic requirements
a) the requirements of personal safety;
b) requirements for the protective equipment that ensures safe operation control;
C) ergonomic requirements for permanent workplace (if control in the workshop environment) or to the organization of the workplace under the control of the design of technical products;
g) lighting requirements of the test objects.
d) ventilation requirements;
e) electrical safety requirements;
g) requirements for the protection of the environment.
A. 2.3 requirements for the level of training and certification of specialists who perform magnetic particle inspection
a) General requirements for training and qualifications of radiographers are permitted to conduct this type of control;
b) number of radiographers who conduct the control (if working at height, slips, tanks, etc.);
C) the frequency of their assessment.
A. 2.4 the test Object and feature finds (detectable) defects
a) the name and number of the test object;
b) material grade of the test object;
C) sketch of the test object, specifying its dimensions;
g) characterization of defects subject to detection on the test object — types, the location, the direction of propagation.
d) areas (zones) to be monitored;
e) the appearance, characteristics of the surface structure of the object in the control zone (surface roughness, presence of fillets, holes, curvature, etc.);
W) thickness (diameter) of the part in the control zone;
I) the type and thickness of the protective coating;
j) the type of permanent connection;
l) availability of the object of control in the design of technical products.
A. 2.5 Applied flaw detector and other equipment and accessories
a) type magnetic particle flaw detector;
b) a device for controlling magnetization and demagnetization of the quality of the test object;
C) a device or other means to estimate the concentration of magnetic powder in suspension;
g) type of control (a validation test) of the sample;
d) that in addition should be in the workplace control: the power supply, compressed air, air compressor, ladder, heater, portable lamp, special screens, locks and other devices.
A. 2.6 Type used magnetic indicator and other welding materials
a) the type of magnetic indicator (magnetic powder, the composition of the dispersion medium, the concentration of powder in the suspension);
b) an organic solvent for washing before and after control;
in) white or yellow contrasting paint (under the control of the black surface of the black magnetic powder);
g) a thick grease to protect the cavities from ingress of slurry;
d) remover for removing the protective coating — in the case of the control object with the paint coating.
A. 2.7 the Procedure for preparation of the object for inspection
a) when control of the object in the product structure, is the necessary dismantling operations on the product;
b) the conditions and methods of cleaning the surface of the test object. The removal of surface grease, dirt, dust. Remove protective coating if its thickness exceeds 50 µm, or it has significant damage;
C) marking of zones;
g) visual inspection of the facility to assess the surface condition, the degree of purification and the discovery of coarse visible defects;
d) mounting the object in a controlled position (centering, clamping fixture, etc.).
A. 2.8 health Check, magnetic particle flaw detector and magnetic indicator
a) organization of the workplace for monitoring the location of equipment;
b) preparation of magnetic particle testing flaw detector to work and connect to a power source;
C) setting the operating mode, the magnetization of the control sample, the application of a magnetic indicator and performance evaluation, flaw detector and magnetic indicator;
g) to verify compliance with the established control parameters (magnetising current, the position of the switches and other controls) to requirements of technical documentation.
A. 2.9 Implementation of control
a) the choice of the method of control (if not specified in the documentation);
b) order placement of a portable flaw detector (under the control outside the stationary working place);
C) setting the control object to the position of magnetization. Illustrations (diagrams, drawings, photographs, showing the relative position of the test object and the magnetizing device at the time of the magnetization);
g) the type and value of the magnetizing current or the tangential magnetic field strength;
d) the order of magnetization;
e) inspection of the control zone;
g) the inspection control with the aim of finding an indicator of drawings in the form of deposits of magnetic powder;
I) analysis of the detected indicator of drawings;
K) control characteristics characteristic areas of the surface of the parts;
l) details of re-operations control;
m) demagnetization of the part;
n) removing traces of magnetic suspension from the surface of the control zone;
p) verification of rozmanitost details.
A. 2.10 interpreting the results of the monitoring and evaluation of the condition of object of control
a) basic and additional characteristics of defects to be detected;
b) methods of interpretation of the results of control;
C) standards of rejection.
A. 2.11 Procedure in case of defects
a) report to the foreman, the foreman or supervisor for a decision.
A. 2.12 Registration of testing results, documentation
a) documentation, in which are recorded the results of control (the accompanying maps, reports, logs, computer memory or other media);
b) the form or manner of recording the results of the registered documents;
in) permissible (recommended) abbreviations and symbols used in the design verification results.
Features and examples the IPC welded joints are given in Appendix K.
A. 2.13 Final operations
a) recommended method of demagnetization;
b) carrying out demagnetization of an object;
C) to check the degree of demagnetization and permissible residual magnetization of the test object;
g) purification of the test object from defected materials;
d) the procedure for bringing the equipment in the storage position, its packing;
e) the instructions for cleaning the workplace.
A. 2.14 Application
If necessary, the how-to (procedure) included technological (operating) the control maps, diagrams, drawings or other illustrations.
Note — the user is allowed brief description of the physical nature and technical capabilities of magnetic particle inspection.
Annex B (reference). The recommended content of operational (process) maps of magnetic particle inspection
Appendix B
(reference)
Operating (technological) map of magnetic particle inspection is a normative-technical document that defines the order of execution of control. For a proper understanding of the text and the precise control technology maps provide illustrations indicating the zones and control schemes of magnetization. Operating (technological) card IPC lead following data:
— requirements for personnel conducting the inspection;
— object material, the number of the drawing;
— material of the test object;
— the type and thickness of the protective or protective and decorative coatings;
— the scheme of object, specifying its dimensions;
— the equipment used and means of verification:
— devices for measurement of magnetic field intensity;
— oversight of rozmanitost of the test object;
— magnetic indicator (type and composition);
auxiliary materials and supplies (brushes, solvent, rags, etc.);
method and means of quality control non-destructive testing of materials;
— type control sample;
— method of control;
— type and value (strength) of the magnetizing current or the value of the required magnetic field strength;
— standards of evaluation;
— the need for and method of demagnetizing, the permissible value of the residual magnetization.
The map can be further specified: the number of components in the kit; discharge; time control; General safety requirements.
Annex b (informative). Examples to verify magnetic particle flaw detectors and magnetic indicators
The App
(reference)
B. 1 General characteristics of control samples
B. 1.1 Samples represent details or special products with artificial or natural defects, such as discontinuities of material in the form of a narrow flat grooves, cylindrical holes or cracks of various origins. They are designed to verify magnetic particle flaw detectors and magnetic indicators. Selection of samples for a particular application carried out in accordance with the guidelines outlined in section 8.
B. 1.2 as artificial defects that serve the narrow flat grooves of different widths or a cylindrical hole with a diameter of 2−2,5 mm, located parallel to the surface at various depths. To prevent corrosion, the samples can be coated with a layer of Nickel or chromium with a thickness of 0.002 to 0.003 mm.
B. 1.3 as samples also use production parts (blocks, cylinders, plates, discs and other specialized products) deliberately (artificially) received cracks. Cracked get:
— by overheating of the samples, usually by repeated, rapid cooling;
— deformation of the sample by bending or stretching or indentation of a punch with a cylindrical or spherical shape of the contact surface, resulting in formation of cracks in pre-hardened surface layer of samples.
B. 1.4 in the manufacture of the samples hardening of the surface layer can be performed:
— chemical-heat treatment — nitriding, cementation, cyanidation, alteromonas, the thermal diffusion chromium plating, boronovanii or other means;
surface heat treatment of high-speed induction heating using high frequency currents;
— a combination of induction heating with the chemical-thermal treatment, for example, by cementation.
B. 1.5 in the formation of oxides on the surface of samples with cracks in the manufacturing process they are subjected to water jet or ultrasonic cleaning and subsequent anti-corrosion treatment (if necessary).
B. 1.6 After producing certificate samples. According to the results of attestation are passport, in which you specify: the manufacturer of the sample, sample number, mark his material, purpose, recommended method and mode of magnetization, the requirements for display materials, types and sizes of defects present on the sample. The sample I enclose the defects recording: cast of existing defects (Appendix G) photograph or sketch.
B. 1.7 When using samples with artificial defects in the form of narrow grooves, made in box, magnetic powder, may form flat pattern in the form of a circle or part thereof along the contour of the insert, and a pattern of lines over the groove. Health assessment of the flaw in this should be performed by the deposition of powder over the groove.
B. 1.8 Samples contained in this application, and the like, varying in shape, size and material from control objects are not allowed to check the possibility of using magnetic particle method for the control of specific objects, evaluation of the detection of them defects, and also to practice modes of the IPC such objects.
B. 1.9 Control samples are not measuring instruments and metrological verification can not be. They shall be subject to assessment of the external condition and periodic inspection (for corrosion, breaks, etc.).
B. 1.10 Assessment of the external condition of the samples is carried out before each application. On the working surface of the samples is not permitted for corrosive ulcers, corrosion products, risks, Nadira, dents, peeling of protective coating and other damage. On samples with artificial defects in the form of narrow grooves, made in the inserts, are not allowed protrusion of the inserts on the working surface of the samples.
B. 1.11 the Suitability of the samples is assessed by detecting defects on them when the magnetization serviceable magnetic particle flaw detector modes, which are calculated on each sample.
B. 2 Examples of specimens with artificial defects
V. 2.1 Sample MO-1
V. 2.1.1 Sample designed to assess the health of the flaw with the magnetizer, having contacts or an electromagnet with a yoke. The specimen is a flat steel plate with dimensions of 18080
12 mm from one surface defect in the form of a narrow flat groove and two sub-surface defects in the form of holes located at different depth from the working surface of the sample (figure V. 1). When the magnetization of the sample on its surface creates inhomogeneous magnetic field, the magnetic field is equivalent to natural defects.
V. 2.2 Sample MO-2
The sample is designed to evaluate the health of the flaw detector pole magnetization using solenoid or cable is wound on the object in the form of a solenoid. The sample (figure B. 2) is a steel bar of size 12030
10 mm, which made one artificial defect-defect material.
V. 2.3 Sample MO-3
The sample is designed to evaluate the health of the flaw detector pole magnetization using a solenoid, a cable wound around the test object in the form of a solenoid, a magnetic yoke. The sample (figure B. 3) is a steel bar of size 12030
10 mm with five sub-surface defects in the form of cylindrical holes with a diameter of 2 mm located at different depths from the sample surface.
Figure B. 1 — Sample MO-1
1 — insert with a defect; 2, 3 — subsurface defects
Figure B. 1 — Sample MO-1
Figure B. 2 — Sample MO-2
1 — brusok; 2 — panel defect 3
Figure B. 2 — Sample MO-2
Figure B. 3 — Sample MO-3
1 — brusok; 2 — a cylindrical hole, closed by a screw M2,5
Figure B. 3 — Sample MO-3
V. 2.4 Sample MO-4
The sample is intended to assess the performance of the fault detectors of the induction and circular magnetization. Sample (figure V. 4) is a disc with a thickness of 15 mm diameter 120 mm center hole with a diameter of 60 mm. On the cylindrical surface of the disk has a surface defect-a defect of the material perpendicular to a generatrix of the cylinder (to operate the fault detectors of the induction of magnetization). On the sample there is also a surface defect the plane of which is parallel generatrix of the cylinder, and three sub-surface defect in the form of holes with a diameter of 2.5 mm located at different depths from the outer cylindrical surface (with the flaw of circular magnetization).
Figure B. 4 — Sample MO-4
1, 2 — surface defects; 3 — subsurface defects — three holes with a diameter of 2.5 mm, located on the cylindrical surface at depths of 2, 3 and 4 mm
Figure B. 4 — Sample MO-4
B. 3 Examples of specimens with artificial cracks
V. 3.1 Sample MO-5
V. 3.1.1 Sample is a plate with a length of 110 mm, a width of 20 mm and a thickness of 4−5 mm, made of steel 2013 according to GOST 5632, cracks in nitrided layer. Allowed the production of samples of other sizes, for example, a length of 300 mm, a width of 38 to 40 mm, thickness 4−5 mm.
V. 3.1.2 the Workpiece is subjected to preliminary machining, and then grind her. Surface roughness less than 1.6 µm according to GOST 2789.
V. 3.1.3 One side of the workpiece is nitrided to a depth of 0.2−0.3 mm in the atmosphere of ammonia. Preliminary heat treatment of the workpiece to nitriding is not carried out. Then the sample is cooled in a furnace to 200 °C in an atmosphere of ammonia, then by air.
V. 3.1.4 to reduce the level of residual stresses in the workpiece is subjected to vacation at a temperature of 150−160°C with a shutter speed of 100−120 min.
V. 3.1.5 Wide surface of the workpiece is polished to a depth of not more than 0.05 mm and with abundant cooling. Polished slim long side edge of the workpiece. The parameter of surface roughness is not more than 1.0 µm according to GOST 2789.
V. 3.1.6 using the metallographic microscope or measuring on a thin long side faces of the workpiece to measure the thickness of nitrided layer. The measurements were carried out at three points on each face of the workpiece. The thickness of the nitrided layer take the average value of six measurements.
V. 3.1.7 Workpiece set nitrided layer down on two parallel pillars screw press, located at a distance of approximately:
— 80 mm for samples with a length of 110 mm;
— 250 mm for samples of length 300 mm.
Tops of supports should have a fillet radius of 2 mm.
V. 3.1.8 On the middle part of the sample set the punch with the cylindrical contact surface with a radius of about 40 mm. Forming cylinder must be perpendicular to the longitudinal axis of the workpiece.
V. 3.1.9 slowly bend the Workpiece in a screw press before the appearance of the characteristic crunch, evidencing the formation of cracks in the nitrided layer.
V. 3.1.10 the resulting sample is marked and subjected to magnetic particle testing. Display the picture of detected cracks photograph or made the defects recording sample in a different way, for example, in accordance with Annex G.
V. 3.1.11 the Sample is demagnetized and cleaned from traces of magnetic suspension.
V. 3.1.12 Measure the width and depth of cracks on metallographic or measuring microscope. The width of each crack is measured not less than five points: in the middle part of the width of the sample (on its longitudinal axis) and on both sides of the longitudinal axis at a distance of about 3 and 6 mm. Determine the average value of the disclosure of each crack.
V. 3.1.13 On the sample make the passport (certificate).
V. 3.2 Sample MO-6
V. 3.2.1 Blank sample made of sheet steel, for example, brand 11KH11N2V2MF according to GOST 5632, in the form of plates with dimensions 13030
3.5 mm. the same size preparing the workpiece and witness samples needed to control the depth of nitriding.
V. 3.2.2 Billet RICHT and grind to a depth of 0.1−0.2 mm. surface Roughness less than 1.6 µm according to GOST 2789.
V. 3.2.3 Mark out the workpiece, highlighting on the one hand each of them five stripes size 205 mm across the longitudinal axis of the sample at a distance of 10 mm from each other (figure V. 5).
Figure B. 5 — Scheme of marking samples
Figure B. 5 — Scheme of marking samples
V. 3.2.4 For two thin lateral faces of the workpieces opposite to each of the selected strips (at a distance of 15 mm from each other) perform milling the slots to a depth of 1 mm. Angle milling cutter 30°.
V. 3.2.5 the Surface of the selected stripes cover perchlorovinyl enamel HV-785, perchlorovinyl lacquer XB-784 or glue HWK-2A on the basis of perchlorovinyl and alkyd resins.
V. 3.2.6 the Workpiece is subjected to a galvanic plating to the thickness of the Nickel 0,05−0,06 mm or galvanizing thickness of zinc 0,04−0,05 mm.
V. 3.2.7 With the blanks and remove the protective layer of enamel (varnish, glue).
V. 3.2.8 the Workpiece is nitrided to a depth of 0.15−0.3 mm. Pre-heat the workpiece to nitriding is not carried out.
V. 3.2.9 To reduce the residual stress, the workpiece is subjected to vacation at a temperature of 180−200°C with a shutter speed of 100−120 min.
V. 3.2.10 Nitrided surface of the workpieces is polished to a depth of not more than 0.05 mm and with abundant cooling. The parameter of surface roughness is not more than 1.0 µm according to GOST 2789.
V. 3.2.11 Of the workpiece and witness samples made microsection and microscope to determine the depth of nitriding.
V. 3.2.12 For cracks billet sample set nitrided layer down on two parallel pillars screw press, located at a distance of about 100 mm On the sample to get cracks, determine their size, made the defects recording and make the passport (certificate) in accordance with the recommendations set out in paragraphs B. 3.1.8-B.
V. 3.3 Sample MO-7
V. 3.3.1 Blank sample made of steel U10A according to GOST 1435 in the form of a cylinder with a length of 250−300 mm, with a diameter of 25 mm allowed the production of billets of steel u7 or U12.
V. 3.3.2 Blank sample is quenched to a hardness of 60−63 HRC.
V. 3.3.3 the Cylindrical surface of the workpiece is polished. The parameter of surface roughness of 0.8 µm according to GOST 2789.
V. 3.3.4 On the cylindrical surface of the workpiece electrolytically applied layer of chromium with a thickness of 0.25−0.30 mm (according to the technology of porous chromium plating).
V. 3.3.5 the Cylindrical surface of the workpiece is polished to a depth of 0.1 mm solid abrasive wheel without cooling when the cross feed 0,03−0,05 mm per double stroke of the longitudinal feed and the 1−3 m/min. While in the chromium coating and the steel base of the workpiece cracks.
V. 3.3.6 the Workpiece is subjected to vacation at a temperature of 160−180°C.
V. 3.3.7 With the surface of the workpiece by the electrolytic method removes the layer of chromium.
V. 3.3.8 the Workpiece is cut along the axis into two or four parts, thus we can get two or four samples of ground cracks.
V. 3.3.9 On the surface of the samples choose areas with cracks, the width of which is close to the minimum size of cracks that are expected to be detected in the controlled products with a length of about 40 mm. the Selected area outline electrocorundum. The width of cracks in the zones measured on the metallographic or measuring microscope.
V. 3.3.10 Specimen label and subjected to IPC. Display the picture of detected cracks photograph or made the defects recording sample in a different way, for example, in accordance with Annex G.
V. 3.3.11 On the sample make the passport (certificate).
V. 3.4 Sample MO-8
V. 3.4.1 Sample represents the object of control or part with natural cracks and artificial defects.
V. 3.4.2 For sample production, which is a test object, select the object from the number rejected in the presence of natural defects or rejected by other parameters. In the absence of natural defects make it artificial defects in the form of inserts or other means. This sample is designed to evaluate performance of magnetic particle flaw detectors and magnetic indicators, and to design and verify the correct implementation of the control technology of such facilities.
V. 3.4.3 On the sample make the passport (certificate).
V. 3.4.4 in Addition to the samples listed in this Appendix can be applied to samples other types of natural or artificial defects.
Appendix d (reference). The technology of manufacturing defects recording
Appendix D
(reference)
G. 1 defects recording is made in the following sequence:
— washed a sample of pure kerosene, solvent or other solvent,
— magnetize the sample,
— put on the sample a thin layer of transformer oil or oil of MK-8 and wipe dry with a clean rag
— applied to the surface of the sample from the gun, a small layer (5−10 µm thick) white or yellow medium or the color developer for color or fluorescent penetrant inspection (through a layer of paint is slightly visible surface of the sample),
— dried layer of paint in 10−15 minutes,
— on the sample cause the magnetic suspension.
When using the suspension water-based sample is dried by exposure to the air. Traces of kerosene-oil suspension is removed by immersing the sample in gasoline.
2 For fixing rollers of a magnetic powder deposited on the defects on the sample surface is short, for (1−3), is applied from a spray gun thin coat of nitro. Dried paint layer for 5−10 min.
G. 3 sample applied sticky tape.
D. 4 Removed from the sample adhesive tape, which should be the layer of paint and flat pattern (defects recording).
G. 5 Applied to the defects recording on a sheet of white paper on which indicate the type and sample number and date of manufacture defectogram.
G. 6 For ease of use the defects recording is placed between two bonded thin plates of organic glass.
Annex D (informative). Determination of the viscosity of the dispersion medium of the magnetic suspension
Appendix E
(reference)
1. the Viscosity of the dispersion medium of the slurry oil-based and oil-kerosene mixtures are measured at their preparation and during the use of the frequency specified in the NTD of the industry or enterprise.
D. 2 Kinematic viscosity measured in accordance with GOST 33 viscometers VPG-1, VPI-2, VPI-4 or a residence permit according to GOST 10028. Allowed to use units that have the same or better characteristics. The viscosity is measured after settling of the slurry at least 1 hour or filter.
D. 3 workplace monitoring allowed to measure the viscosity of the dispersion medium of the suspension with viscosimeter type VZ-246 according to GOST 9070 with a nozzle diameter of 2 mm or viscometer VZ-1 with a nozzle diameter of 2.5 mm. this filtering sucks or long-term suspension is not required. The magnetic slurry is poured into the reservoir of the viscometer until the level of the cusps of the hooks present on the inner wall of the tank, which corresponds to a volume of 100 ml Under the nozzle of the viscometer is clean and dry put the capacity at least 120 ml. Measure time (in seconds) of the continuous of liquid outflow through the nozzle viscometer. The expiry time of the fluid multiplied by the correction factor K specified on the cover of the viscometer. The obtained result is taken as viscosity of the dispersion medium of the magnetic suspension. If necessary, it is converted to kinematic. Graph of arbitrary kinematic viscosity when using the viscometer VZ-1 is shown in figure D. 1. The kinematic viscosity of 36 x 10m
/s (36 SST) specified in the standard, corresponds to 92 viscosity by viscometer VZ-1 and a viscosity of 10·10
m
/s (10 cSt) — 47 s.
Figure D. 1 — Graph of arbitrary viscosity of the dispersion medium of magnetic suspension, as measured by the viscometer VZ-1 with nozzle diameter 2,5 mm, kinematic viscosity
Figure D. 1 — Graph of arbitrary viscosity of the dispersion medium of magnetic suspension, as measured by the viscometer VZ-1 with nozzle diameter 2,5 mm, kinematic viscosity
Annex E (informative). The choice of method of control
Annex E
(reference)
E. 1 Method of control is selected depending on the magnetic properties of the material of the inspected object. To do this:
— determine the material grade of the inspected object, using the technical documentation for its production;
— determine the value of the coercive force and residual induction
of the material of the object using the appropriate reference books on magnetic properties of steels;
— on the graph (figure E. 1) the abscissa shows the delay value of the coercive force and the axis of ordinates the value of the residual induction
of the material of the test object.
Figure E. 1 — the Schedule choosing a method of magnetic particle inspection
Curve 1 is the locus of points equal to the specific magnetic energy of the material with tolerance limits within ±10%
Figure E. 1 — the Schedule choosing a method of magnetic particle inspection
E. 2 Based on the position coordinates and
on the graph, make a conclusion about possibility of application of a particular method of control in accordance with the following:
— if the chart point (,
) is located above or on the curve, it is possible to control the object like a DREAM, and SPP;
— if the point (,
) is located below the curve, it is advisable to check that only SPP.
Annex W (informative). Types, methods and schemes of magnetization
App W
(reference)
Examples, methods and diagrams of magnetization are given in table J. 1.
Table J. 1
| View of the magnetization | Method of magnetization | Magnetization system and the location of detected defects |
Formulas for determination of the magnetizing current |
| Circular (C) | The current object (TSO) | 1 is a longitudinal defects; 2 — radial defects; 3 — pin disk; 4 — object; 5 — conductor; |
where |
| A current is passed through the Central conduit (CPU) | 1, 2, 3 — faults; 4 — object, 5 — conductor; |
where | |
| The current phase of the object (CE) | 1 — defective, 2 — object, 3 — contacts, 4 — zone control, |
Approximate power AC, DC and the rectified current transmitted through the object using the contacts, determined by the formula:
When using pulsed current force is determined according to the schedule. The required magnetic field strength current is determined by the formula:
In formulas: | |
| Circular (C) | With the use of a toroidal winding (CG) | 1, 2, 4 — defects, 3 — coil, 5 — object, 6 — the middle line of the toroid, |
When |
| Induced current in the object (QI) | 1 — testing object; 2 — solenoid; 3 — winding. Arrows indicate detectable cracks |
- | |
| Pole (P) | Pole in the solenoid (PS) | 1 — solenoid; |
where
where |
| Pole (P) | The magnetization of the DC solenoid (PE) | 1 — testing object; 2 — fissure; 3 — magnetic core; 4 — winding; 5 — pole movable plate; 6 — terminals for connecting a DC source |
- |
| The magnetization in the electromagnet AC (PE) | 1 — testing object; 2 — fissure; 3 — movable poles; 4 — magnetic circuit; 5 — coil; 6 — terminals for connecting the AC source |
- | |
| Magnetization of a portable electromagnet (PE) | 1 — testing object; 2 — pole terminals; 3 — magnetic core; 4 —coil; 5 — cracks |
- | |
| Pole (P) | The magnetization device is a permanent magnet (PM) | 1 — testing object; 2 — fissure; 3 — magnetic core; 4 — blocks of permanent magnet |
- |
| Combo (circular and pole) (n, P) | By passing currents in the object and through the winding of the solenoid (AC and PS) | 1 — object; 2 — solenoid; 3, 4 — longitudinal and transverse cracks; 5 — pin disk; |
- |
| Combo (K) | The current facility and with the help of the electromagnet (co, PE) |
|
- |
| By passing the current object and by using solenoid (AC, PS) |
|
- | |
| Combo (K) | By passing the object of the two currents in mutually perpendicular directions (TSO, TSO) |
|
- |
| Induced current in the object and passing a current through a conductor placed in a through hole in the object (QI, CP) |
|
- |
,
,
.
.
, when 
,
, cm; 
,
,
Notes
1 Under the combined magnetization the magnetizing current for the circular, and the pole of magnetization is determined by the above formulas.
2 allowed to set the mode of magnetization experimentally on samples of the parts with defects.
3 in Addition to those in the table use the schema of the magnetization using permanent magnets, electromagnets, and other means of induction and the combined magnetization.
Application And (reference). Determine the required intensity of the applied magnetic field
The Application And
(reference)
I. 1 To determine the magnetic field for controlling objects of SPP:
— determine the material grade of the inspected object, using the technical documentation for its production;
— determine the value of the coercive force of the material of the object according to the corresponding directories on the magnetic properties of steels;
— graphs 1 and 2 (figure I. 1 figure I. 2) or the formulas (9, 10) for the value determines the maximum value
;
— choose the value of the intensity of the applied field in the range from to
In justified cases it is allowed to reduce or increase the magnetic field intensity, a certain chart.
I. 2 in the control of complex objects, in the presence of deposition of powder on false defects, the detection of texture of the material and in other cases I specify the selected value of the intensity of the applied magnetic field with respect to the specific object of control, guided by industry research.
Figure I. 1 Is a Graph for determining the intensity of the applied magnetic field taking into account the coercive force of the material (in H (c)<16 A/cm)
1 — the maximum value of field strength;
2 — the minimum field-strength value
Figure I. 1 Is a Graph for determining the intensity of the applied magnetic field taking into account the coercive force of the material (if <</em>16 A/cm)
Figure I. 2 — a Graph to determine the intensity of the applied magnetic field taking into account the coercive force of the material (H (c)≥10 A/cm)
1 — the maximum value of field strength;
2 — the minimum field-strength value
Figure I. 2 — a Graph to determine the intensity of the applied magnetic field taking into account the coercive force of the material (10 A/cm)
Annex K (informative). Examples of magnetic particle inspection of welded joints
App To
(reference)
K. 1 General provisions
K. 1.1 Welded joints of products for different purposes magnetic particle control method using switch contacts, electromagnets, devices based on permanent magnets, solenoids or flexible cables. For magnetizing of objects using magnetic field AC, DC, pulsed and DC currents. Depending on the magnetic properties of the material of the inspected object, the inspection of welds is carried out by the method applied field (SPP) or the method of residual magnetization (SLEEP).
K. 1.2, With the IPC seams magnetized only a limited area of the object, which is called the controlled section (KU). The dimensions of this area depend on the type of magnetizer and current (magnetic field). The magnetizing current is determined by the experimental formulas and graphs, using formulas in electrical engineering or control samples representing the control object or part with natural or artificial defects.
K. 1.3 Magnetic particle inspection of butt, lap, tee and corner welds, as a one-way, including the flanging of the edges and bilateral, is carried out as the following examples (if you have access to the seams). Butt welds with check lining on one side only, where there is no lining.
K. 1.4 If necessary, tested welded joints demagnetize the sections in the same order as carry out their control. For demagnetization of welded joints the pole pieces of an electromagnet mounted on KU as in the magnetization, turn on the power supply of the electromagnet and slowly remove it from the weld surface at a distance of 50−60 cm
K. 2 weld inspection with the use of contacts
K. 2.1 Controlled area, the modes of magnetization
When using switch contacts are identified defects, the plane of which is directed along the line joining the mounting points of contacts. Figure K. 1 shows the location of switch contacts 1A-1B defects, which are located across the direction of the weld. Controlled area KU dashed line. Length of the controlled area depends on the distance
between the installation points of contacts. The distance between the contacts is taken equal to the range of 50−200 mm. Adjacent to the contacts area
, the width of which is approximately equal to 20 mm, are zones of aviavlasti defects. Length of KU is equal to:
The width of the targeted area when using a constant, rectified, and pulsed currents are equal:
and when using AC:
For detection of defects propagating along the weld, the contacts mounted on the weld or beside it so that the line connecting the mounting points of contacts, is placed along the seam. Under the control of the long seam contacts in pairs moving along the seam so that the monitoring area overlap of not less than 20 mm (figure K. 2).
The strength of the current transmitted through the object using switch contacts, when the magnetization variable, constant and rectified currents is determined by the formulas given in Appendix G. If you use pulsed current it force is determined according to the schedule (figure K. 3).
K. 2.2 Control of the weld pulse current applying contacts
For detection of longitudinal defects in the magnetization pulse current under the control of SPP on the site of the weld electric current with simultaneous application of magnetic suspension. Inspection the seam for the detection of defects is carried out after switching off the current. When you SLEEP monitoring first magnetize portions of the whole weld (figure K. 2), then applied for a suspension and inspect. Contacts move, alternating between them.
When the magnetization of the contacts is installed next to the weld bead, i.e. outside the control zone, as areas with a radius of 3−5 mm around the mounting points of the switch contacts are magnetized inefficient and defects in them are not detected.
For detection of transverse defects, the terminal sets on both sides of the weld. First magnetize a first portion, applied to the suspension and inspect. Then in the same order and check all other areas of the seam.
K. 2.3. Control of welded joint overlap for detection of longitudinal defects in the weld and in the HAZ
The diagram of the permutation switch contacts for detection of longitudinal defects in the weld and heat affected zones shown in figure K. 4. Control is focused on three areas. First set the contacts to position 1A-1B to control the first phase — the left of the weld zone. After magnetization, the application of slurry and inspection installing the switch contacts to weld in the situation 2A-2B and spend control. Then the switch contacts is mounted on the third section, on the right the heat-affected zone in the position 3A-3b, and carried out her control.
K. 2.4 testing of welded joints lap joint for detection of transverse cracks in the weld and heat-affected zones
Control of welded joints lap joint is carried out on sites. The weld and heat affected zone pre-marked on the plots. Figure K. 5 shows the position of the switch contacts at the three sites. First check the first KU. For this purpose, the switch contacts set to position 1A-1B, the leak current, is applied to the suspension and examine this CUE. Then carry out the control of the second KU. To do this, set the switch contacts in position 2A-2B, electric current, applied to the suspension and examine IMMEDIATELY. Then in the same order and check the third and the other KU.
Figure C. 1 — layout of the controlled area KU a length B width C at the weld seam with the use of switch contacts in order to detect transverse cracks
zone of aviavlasti defects (
- the distance between the installation points of contacts; KU — controlled phase (dashed line)
Figure C. 1 — layout of the controlled area of the KU length width
at weld seam with the use of switch contacts in order to detect transverse cracks
Figure C. 2 — Diagram of the magnetization on sites under the control of the weld length of a large pulse of current for detection of longitudinal cracks (indicated by arrows)
1, 2, 3 — magnetized areas; E1, E2 — the location of the contacts
Figure C. 2 — Diagram of the magnetization on sites under the control of the weld length of a large pulse of current for detection of longitudinal cracks (indicated by arrows)
Figure K. 3 — Graph of pulse current and distance between contacts
Figure K. 3 — Graph of pulse current and distance between contacts
Figure K. 4 — the arrangement of switch contacts for detection of longitudinal cracks (shown by arrows) on the weld and heat-affected zones of welded joint overlap
1a-1B, 2a-2B, 3A-3b position switch contacts on the control sites
Figure K. 4 — the arrangement of switch contacts for detection of longitudinal cracks (shown by arrows) on the weld and heat-affected zones of welded joint overlap
Figure K. 5 — the arrangement of contacts upon detection of transverse cracks (arrows) on the weld and heat-affected zones of welded joint overlap
1a-1B, 2a-2B, 3A-3b — position of the switch contacts on the control sites
Figure K. 5 — the arrangement of contacts upon detection of transverse cracks (arrows) on the weld and heat-affected zones of welded joint overlap
K. 2.5 Control long weld cross-permutation switch contacts for detection of differently oriented defects
For the detection of differently oriented defects in the weld bead double check:
a) passing a current along the weld seam for detection of longitudinal defects;
b) the current in the direction perpendicular to the weld seam for the detection of transverse defects.
For the detection of differently oriented defects also used another method in which each controlled area double check, magnetizing it in two ways. To check follow-up phase is started after the previous control. Installation diagram of switch contacts, the location of the WELL, their size with this method is shown in figure K. 6. First section check in this order: set the switch contacts in position 1A-1B, magnetize, is applied to the suspension, KU inspected to detect defects. Then the switch contacts installed in position 2A-2B, magnetize, is applied to the suspension and inspect again. Similarly check other areas of the weld.
K. 3 inspection of welded joints with the use of electromagnets
K. 3.1 Controlled area when testing the weld with the use of electromagnet
Scheme of the position of the electromagnet when the weld seam for the detection of longitudinal cracks is shown in figure K. 7. The pole pieces of the electromagnet set approximately symmetrically with respect to the weld. Areas adjacent to the pole tip width of 20 mm, are zones of aviavlasti defects.
Length of the targeted area is determined by the distance between the pole pieces and the size of the zones of aviavlasti, i.e.:
Width of the controlled area equal to:
When using an electromagnet fed by a constant or rectified current, the control perform a CAF. Control objects using the AC electromagnet carry out a CAF or a DREAM. When installing the solenoid to check the plot you want to ensure a good fit of the pole pieces to check the site, i.e. create a good magnetic contact.
K. 3.2 weld inspection neglecting connection with the use of an electromagnet to detect longitudinal and transverse defects
For detection of longitudinal defects in weld bead and in heat affected zones of the weld control plots (figure K. 8A). The pole pieces of the electromagnet installed on both sides of the weld. To control the first q bits set to 1A-1B. Under the control of SPP include the current in the electromagnet, causing magnetic suspension and running current, visiting KU.
In the control of SLEEP (if you are using the AC electromagnet) after setting the pole pieces to position 1A-1B turn on and turn off current. Then the area of the WELL is applied to a magnetic suspension and looking at her now.
Similarly, check the other areas controlled by setting the electromagnet pole pieces in position 2A-2B, 3A-3b.
For the detection of transverse cracks in the poles of the electromagnet can be mounted next to the weld by its different directions (figure K. 8 b). This is especially desirable if it is difficult to provide a good magnetic contact of the pole tip with a welded seam.
K. 3.3 extended Control of the weld using DC solenoid for the detection of transverse cracks
Control long weld with the use of an electromagnet fed by a constant or rectified current, to detect transverse cracks is carried out by way of a magnetic field applied in the plots (figure K. 9). The electromagnet is removed the weld seam without the alternation of the poles. To ensure the overlap of adjacent plots distance between the places of installation of the poles 2A-1B must be at least 20 mm.
Figure K. 6 — Diagram mounting the switch contacts on the long weld seam for the detection of differently oriented cracks (indicated by arrows) on the weld and heat-affected zones
a diagram of a parallel permutation switch contacts and areas of control;
b — diagram of a cross-permutation switch contacts welded seam;
1A-1B, …, 6A-6b — the location of the contacts; ,
- width and length of the targeted area
Figure K. 6 — Diagram mounting the switch contacts on the long weld seam for the detection of differently oriented cracks (indicated by arrows) on the weld and heat-affected zones
Figure K. 7 — layout of the controlled area at the weld seam with the use of an electromagnet to detect longitudinal cracks
1 — pole pieces; ,
- the length and width of the targeted area; and — area of aviavlasti defects;
- the distance between the pole tips
Figure K. 7 — layout of the controlled area at the weld seam with the use of an electromagnet to detect longitudinal cracks
Figure K. 8 — the Location of the poles of the electromagnet for detection of cracks in the weld and heat-affected zones of welded joints lap joint
and is the location of the poles for the detection of longitudinal cracks; b — the same to identify transverse cracks; 1A-1B, 2A-2B, 3A-3b, 4A-4B — installation site pole pieces of the electromagnet; 1, 2, 3 — controlled areas; 4, 5 — zone of overlap; — the width of the targeted area
Figure K. 8 — the Location of the poles of the electromagnet for detection of cracks in the weld and heat-affected zones of welded joints lap joint
Figure K. 9 — the Scheme of permutations of pole pieces of a DC solenoid for control of a long weld seam for the detection of transverse cracks (arrows)
1A-1B, 2A-2B, …, -
,
- the place of installation pole pieces of the electromagnet;
— distance between the places of installation pole pieces
Figure K. 9 — the Scheme of permutations of pole pieces of a DC solenoid for control of a long weld seam for the detection of transverse cracks (arrows)
K. 3.4 Monitoring the long weld seam with the use of DC solenoid for the detection of multi-directional cracks
Control hold SPP in the plots, each tested twice (figure K. 10 a): first, set the pole pieces to position 1A-1B, magnetize, is applied to magnetic suspension, and a visiting KU. Then the electromagnet is set to the 2A-2B and conduct the full cycle of magnetic control. At the same time found a multi-directional cracks.
Then hold control when you install the electromagnet to the provisions of the pole pieces 3A-3b, 4A-4B, -
, (
) - (
). The location of the pole pieces and the controlled areas shown in figure K. 10 b.
In this figure, the width of the targeted area. Area of aviavlasti defects is approximately equal to 20 mm. the Distance between pole pieces of adjacent land equal to
K. 4 testing of butt welded seam on tubular design with the use of a solenoid (coil cable)
For testing of butt weld in tube design cable wound on both sides of the seam (figure K. 11). For magnetization of the control zone is recommended to provide approximately 10000−12000 ampere-turns in the control of SLEEP and 8000−10000 ampere-turns under the control of SPP. Zones 4 and 5 adjacent to the turns of the solenoid, are zones of aviavlasti defects. With this method of magnetization on the weld revealed longitudinal cracks.
Figure K. 10 — Diagram mounting pole pieces of the electromagnet constant current while monitoring weld areas for the detection of multi-directional cracks
and — the position of the pole pieces; b — position of the areas of control of KU; - the distance between pole tips;
- the distance between the places of installation pole pieces; ZN — zone of aviavlasti defects; KU — controlled areas (shaded); P — area of the overlap of KU; SSH — welded seam;
,
- width and length of the targeted area
Figure K. 10 — Diagram mounting pole pieces of the electromagnet constant current while monitoring weld areas for the detection of multi-directional cracks
Figure K. 11 — testing of butt welded seam on tubular design with the use of winding cable
1 — tubular construction; 2 — winding cable; 3 — weld; 4, 5 — zone aviavlasti cracks; — the magnetizing current in the winding of the solenoid
Figure K. 11 — testing of butt welded seam on tubular design with the use of winding cable
Bibliography
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| [2] recommendations 2377−96* | State system for ensuring the uniformity of measurements. Development and certification of measurement procedures |
| ________________ * Probably, the error of the original. Should read: MI 2377−98. — Note the manufacturer’s database. | |
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| UDC 620.179.141: 006.354 | OKS 17.220.99; 77.040.20 | |
Key words: nondestructive testing, magnetic particle inspection, test object, requirements for equipment, flaw detector, penetrant testing materials, magnetic powder, suspension, magnetization, controlled surface inspection, detection of defects, safety requirements | ||
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M.: STANDARTINFORM, 2016
