GOST R ISO 10893-7-2016
GOST R ISO 10893−7-2016 seamless steel Tubes and welded. Part 7. Digital radiographic testing of welds for detection of defects
GOST R ISO 10893−7-2016
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Seamless steel tubes and welded
Part 7
Digital radiographic testing of welds for detection of defects
Seamless and welded steel tubes. Part 7. Digital radiographic testing of the weld seam for the detection of imperfections
OKS 23.040.10
77.040.20
77.140.75
Date of introduction 2016−11−01
Preface
1 PREPARED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders», non-state educational institution of additional professional education, Scientific-training center «testing and diagnostics» (RTC «testing and diagnostics») and Open joint stock company «Russian scientific research Institute of pipe industry» (JSC «RosNITI») on the basis of their own translation into the Russian language the English language version of the standard specified in paragraph 4
2 SUBMITTED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders»
3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of April 1, 2016 N 237-St
4 this standard is identical to international standard ISO 10893−7:2011* «non-destructive testing of steel tubes. Part 7. Digital radiographic testing of the weld of welded steel tubes for detection of defects» («Non-destructive testing of steel tubes — Part 7: Digital radiographic testing of the weld seam of welded steel tubes for the detection of imperfections», IDT).
An international standard developed by ISO Technical Committee ISO/TC 17 «Steel», Subcommittee SC 19 «Technical delivery conditions for pipes working under pressure».
The name of this standard changed with respect to names specified international standard to link with the names adopted in the current national set of standards.
In applying this standard it is recommended to use instead of the referenced international standards corresponding national standards of the Russian Federation, details of which are given in Appendix YES
5 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 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 the monthly index" National standards".
In the complex of ISO 10893 under the name «non-destructive testing of steel tubes» includes:
— part 1. Automatic electromagnetic inspection of steel seamless and welded tubes (except tubes produced by arc welding under flux) for verification of the tightness;
— part 2. Automatic inspection eddy current seamless and welded steel pipes (excluding pipes obtained by arc welding under flux) for detection of defects;
— part 3. Automatic control method of magnetic flux leakage around the entire circumference of seamless and welded pipes made of ferromagnetic steel (except tubes produced by arc welding under flux) for the detection of longitudinal and/or transverse defects;
— part 4. The control method of penetrating liquids seamless and welded steel tubes for the detection of surface defects;
— part 5. Control method of magnetic particles seamless and welded pipes made of ferromagnetic steel for detecting surface defects;
— part 6. Radiographic testing of the weld of welded steel tubes for detection of defects;
— part 7. Digital radiographic testing of the weld of welded steel tubes for detection of defects;
— part 8. Automatic ultrasonic testing of seamless and welded steel tubes for the detection of laminations;
— part 9. Automatic ultrasonic testing for the detection of laminations in the strip/sheet metal used to manufacture welded steel pipes;
— part 10. Automatic ultrasonic testing along the whole circumference of seamless and welded steel pipes (excluding pipes obtained by arc welding under flux) for the detection of longitudinal and/or transverse defects;
— part 11. Automatic ultrasonic testing of the weld of welded steel tubes for the detection of longitudinal and/or transverse defects;
— part 12. Automatic ultrasonic control of thickness around the circumference of seamless and welded steel pipes (excluding pipes obtained by arc welding under flux).
1 Scope
This standard establishes requirements for digital x-ray testing x-rays longitudinal or spiral weld steel pipe, automatic arc fusion welding, for detecting defects with the use of computer radiography (CR) or radiography with digital detector arrays (DDA). This standard specifies acceptance levels and calibration procedure.
This standard can be applied for control of closed hollow profiles.
2 Normative references
For the application of this standard requires the following referenced documents are*. For undated references, use the latest edition of the referenced document, including all changes:
ISO 5576 nondestructive testing. Industrial radiology using x-rays and gamma rays. Dictionary (ISO 5576 Non-destructive testing — Industrial X-ray and gamma-ray radiology — Vocabulary)
ISO 9712 non-destructive testing. Qualification and certification of personnel (ISO 9712 Non-destructive testing — Qualification and certification of NDT personnel)
ISO 11484 steel Products. System qualification of the employer for personnel for non-destructive testing (ISO 11484 Steel products — Employer''s qualification system for nondestructive testing (NDT) personnel)
ISO 17636 non-destructive Control of the welded joints. Radiographic testing of welded joints obtained by melting (ISO 17636 Non-destructive testing of welds — Radiographic testing of fusion-welded joints)
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ISO 17636 replaced by ISO 17636−1 «testing of welded joints non-destructive. Radiographic control. Part 1. Methods of x-ray and gamma radiation using the film» and ISO 17636−2 «testing of welded joints non-destructive. Radiographic control. Part 2. Methods of x-ray and gamma radiation with digital detectors».
ISO 19232−1 nondestructive testing. Image quality in x-ray images. Part 1. Determining values of image quality using indicators of image quality, wire type (ISO 19232−1 Non-destructive testing — Image quality of radiographs — Part 1: Determination of the image quality value using wire-type image quality indicators)
ISO 19232−2 nondestructive testing. Image quality in x-ray images. Part 2. Determining values of image quality using indicators of the quality of the image type, step/hole (ISO 19232−2 Non-destructive testing — Image quality of radiographs — Part 2: Determination of the image quality value using step/hole-type image quality indicators)
ISO 19232−5 non-destructive Control. Image quality in x-ray images. Part 5. Determination of the values of blur using indicators image quality of duplex type wire (ISO 19232−5 Non-destructive testing — Image quality of radiographs — Part 5: Determination of the image unsharpness value using duplex wire-type image quality indicators)
3 Terms and definitions
This standard applies the terminology of ISO 5576 and ISO 11484 and the following terms with respective definitions:
3.1 pipe (tube) Hollow long product, open at both ends, of any shape in cross section.
3.2 welded tube (welded tube): Pipe manufactured by forming a hollow profile from a flat product and welding adjacent edges together, and which after welding can be further processed (hot or cold) to its final dimensions.
3.3 the manufacturer (manufacturer): Organization that manufactures products in accordance with the relevant standards and States the conformity of the delivered products with all applicable provisions of the relevant standard.
3.4 agreement (agreement): a Contractual relationship between the manufacturer and the customer at the time of enquiry and order.
4 General requirements
4.1 If the specification for the products or the agreement between the customer and the manufacturer do not stipulate otherwise, the radiographic examination should be carried out on tubes after completion of all primary technological operations of production (rolling, heat treatment, cold and hot deformation, processing size, pre-edits, etc.).
4.2 Control should be carried out only by trained operators, qualified in accordance with ISO 9712, ISO 11484 or equivalent documents related to and under the supervision of competent personnel appointed by the manufacturer (the manufacturer). In case of inspection by a third party this must be agreed between the purchaser and the manufacturer. Control by permission of the employer must be conducted in accordance with written procedure. The procedure of nondestructive testing must be coordinated by a specialist 3 level, and personally approved by the employer.
Note — the Definition of levels 1, 2 and 3 to watch in relevant international standards, e.g. ISO 9712 and ISO 11484.
4.3 Pipe must be sufficiently straight to ensure the possibility of control. The surface of the weld and adjacent base metal shall be free from foreign matter and irregularities, which may affect correct interpretation of the radiograms.
Allowed the grinding surface to achieve acceptable surface quality.
4.4 deleting a strengthening of the weld, the markers (usually lead arrows) should be located in every area of the seam so that it was possible to identify its position on the radiographic image. Alternatively, to determine the position of the weld can be used in an integrated system for automatic positioning.
4.5 Symbols for identification, usually in the form of lead letters, should be placed in each area dispatches to image data of symbols appear on each radiograph to ensure unequivocal identification of the site. Alternatively, to determine the position of each radio messages along the weld seam may be used in an integrated system for automatic positioning.
4.6 the Surface of the pipe from the source of radiation should be provided with permanent markings to provide reference points to determine the exact situation of each radiogram. Alternatively, the automatically determined position of the radio messages can be displayed on the display screen of the digital image software to determine the exact position.
4.7 When carrying out radiation monitoring of the weld of the great length of pipe or tube wall should pass between the x-ray tube and detector at a speed, sufficient for guaranteed detection of the defect, or the pipe should be moved with stops, and radiographic examination should be carried out on a stationary pipe.
5 Equipment
Alternatively, the radiographic film can be used the following methods of digital imaging:
a) computer radiography (CR) using storage phosphor plates (for example, [9] and [10]);
b) radiography using digital detector arrays (DDA (e.g. [11]);
c) digital radioscopy with the formation of the image (e.g. [6], [7] and [8]).
6 control Technology
6.1 the Weld must be controlled using digital radiographic inspection in accordance with section 5, the enumeration of a)-C).
6.2 In accordance with ISO 17636 shall be equipped with two-class image quality:
class a: method of radiographic inspection standard sensitivity;
class B: radiographic testing method with improved sensitivity.
Note — For most products is enough use of the image quality class A. Image quality class B intended for use in the case where improved sensitivity is required to identify all detected defects.
Required class image quality must be set to the appropriate specifications for the products.
6.3 Digital image must conform to the quality class A or B.
6.4 the Central axis of the beam of radiation should be directed to the center of the controlled area of the weld perpendicular to the surface of the pipe at this point.
6.5 Length studied in a single exposure of a site should be such that the difference in the illuminated thicknesses at the ends of the informative section of the detector does not exceed the thickness of the illuminated in its center by more than 10% for image quality class and more than 20% for image quality class And, provided that you meet the requirements of 6.9 and section 7.
6.6 you Should use the method of x-raying through one wall. If this method cannot be applied on geometrical considerations, by agreement between the manufacturer and the customer allowed the use of the method of scanning through two walls, if this can be achieved the required sensitivity.
6.7 the gap between the detector and the surface of the weld should be minimum (no larger image).
The minimum value of the distance f from the source of radiation to the object of control should be chosen so that the ratio of the distance to an effective focal spot size d, i.e.f/d, consistent with the values given by the following formulas:
for image quality class A:
for image quality class B:
where b — the distance between the surface of the weld from the radiation source and the sensitive surface of the detector, mm.
Note — this relationship is Graphically presented in figure 1.
Figure 1 — Nomogram for determining the minimum distance from the source to the weld f against the distance from the weld line from the radiation source to the detector b and the effective focal spot size d
Figure 1 — Nomogram for determining the minimum distance from the source to the weld f against the distance from the weld line from the radiation source to the detector b and the effective focal spot size d
6.8 Obstacle in the application of DDA systems is the large size (over 50 µm) of the matrix element in comparison with the small grain size of the film (which gives the tape very high spatial resolution).
Therefore, it may be impossible to achieve the required geometric resolution, settings (settings), typical for film radiography. These difficulties can be overcome by the use of geometric magnification to achieve the required geometric resolution, or using the compensation principle (increase the signal-to-noise ratio (SNR) of the image), as described in 7.1. Resolves any combination of these measures.
6.9 Conditions of exposure, including voltage x-ray tube should be such as to conform to the requirements for image quality indicators (IQI), as specified in section 7. Contrast and brightness should be adjusted according to the requirements of viewing digital images.
6.10 To maintain a sufficient contrast sensitivity, x-ray tube voltage must not exceed the maximum values indicated in figure 2. Allowed voltage above the specified level, subject to the achievement of minimum acceptable sensitivity.
Figure 2 — Maximum voltage x-ray tube for x-ray machines with a capacity of up to 500 kV as a function of the thickness being radiographed
X — illuminated thickness, mm; Y — voltage x-ray tube, kV
Figure 2 — Maximum voltage x-ray tube for x-ray machines with a capacity of up to 500 kV as a function of the thickness being radiographed
7 image Quality
7.1 image Quality should be determined by using image quality indicators (IQI) one of the types specified in ISO 19232−1, ISO 19232−2 and ISO 19232−5, by agreement between the purchaser and the manufacturer. The appropriate IQI should be placed on the surface of the weld from the radiation source on the base metal adjacent to the weld seam (see figures 3 and 4).
In the case of IQI, wire type, not less than 10 mm of the wires should be visible on the base metal.
Figure 3 — Location of IQI (basic requirements)
1, the Central axis of the beam; 2 — wire type IQI, the thin wire is farthest from the Central axis of the beam; 3 — dubrovytsky type IQI rotated approximately 5°; 4 — speed IQI hole-type is the most delicate step is farthest from the Central axis of the beam; 5 — IQI plate type expansion joint (gasket); 6 — outer reinforcement of the weld; 7 — tube; 8 — the internal weld reinforcement; and is a fixed length of the weld (DDA) or the length of the image plate (CR)
Figure 3 — Location of IQI (basic requirements)
Figure 4 — Types of image quality indicators (IQI)
Figure 4 — Types of image quality indicators (IQI)
If there is no access to the surface of the weld from the source of radiation, the IQI should be placed from the detector. In this case, next to the IQI should be placed the letter «F», and this change in the procedure must be recorded in the minutes control. The location of the IQI from the detector usually gives the opportunity to see in the image on one or two of wire, or holes larger than in the case of placing the same IQI from the radiation source. Customer may request comparative tests on the sample pipe with the location of the IQI from the radiation source and the detector.
If the controlled tubes are the same size and order requirements, you can use the IQI every 4 hours or twice per shift to check the sensitivity of the image. When testing the sensitivity of the IQI should always be from the side of the radiation source.
The parameters used in the trial exhibits (setup x-ray source, detector and their location) should not change for subsequent images, obtained with IQI on the same side as the detector. For stationary systems and processes, such as automated control system using DDA, it is enough to confirm the image quality times per shift, provided that the pipe dimensions, pipe material and control settings remain unchanged. In this case, the image quality checks must be done with IQI, located only on the side of the radiation source.
In accordance with ISO 19232−5, when using IQI dubrovackog type should be measured blur .
The value of the evidence of confusion for IQI dubrovackog is the smallest number of the pair of wires (max. diameter of the wire) is indented less than 20%, which is measured using a cross section of two wires in a digital image.
Dubrovackog type IQI shall be placed at an angle of approximately 5° relative to the orientation of the pixel in order to avoid the effect of aliasing.
The basic spatial resolution SRdetector with fixed position and program parameters should be determined by the position of the IQI dubrovackog type directly in front of the detector. In this case, SR
is determined by the following formula
The principle of compensation
If the sensitivity of the IQI to tables 1 and 2 (IQI wire type, with hole or dubrovackog type) cannot be achieved the system of control, improving the visibility of a single wire can be compensated by a high value of blur.
Example — For of pipe wall thickness 10 mm, grade of quality, it is necessary to apply the IQI wire type W14 or dubrovackog type D11. If D11 cannot be achieved, it is possible to compensate: at lower of two values from D11 to D9, is an increase on two values from W14 to W16.
Table 1 — Raying through one wall — Class quality And
Dimensions are in millimeters
| Set- tion wall thickness T |
Room wire diameter | Set Lenna wall thickness T |
The number of holes, diameter | Set Lenna wall thickness T |
IQI dubrovackog type | |
