GOST R 56185-2014

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  ГОСТ Р 56185-2014

GOST R 56185−2014 Technical diagnostics. Acoustic method for determination of the stress state of shells of vessels working under pressure. General requirements

GOST R 56185−2014

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Technical diagnostics

ACOUSTIC METHOD FOR DETERMINATION OF THE STRESS STATE OF SHELLS OF VESSELS WORKING UNDER PRESSURE

General requirements

Technical diagnostics. Evaluation of stresses in the sides of pressure vessels by ultrasound
General requirements

OKS 77.040.10

Date of introduction 2016−01−01

Preface

1 DEVELOPED by the Open joint-stock company «Scientific-research center of control and diagnostics of technical systems» (OAO «nits KD»)

2 SUBMITTED by the Technical Committee for standardization TC 132 «Technical diagnostics"

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology dated 24 October 2014 N 1410-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 information 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 (gost.ru)

Introduction

Thin-walled vessels carbon and low alloy steels are one of the most common types of equipment and industrial facilities. They find application in chemical and petrochemical industry, ammonia is used in refrigeration plants and air separation as air receivers, etc.

The installation and operation of vessels for critical applications working under pressure associated with the impact on their stress state of many different factors that it is not always possible to take into account in strength calculations. These factors include the presence of additional elements, fittings, pipes, etc., and also influence not amenable to the theoretical view of the external environment.

Direct measurements of mechanical stresses at the control points of the sides of the vessels working under pressure, can be effectively used to verify the correctness of these calculations and for operational diagnostics of technical condition of vessels.

One of the most promising methods for measuring mechanical stresses in the material without its destruction is an acoustic method based on provocations effect — the linear dependence of the velocity of propagation of elastic waves from stresses [1], [2], reliable experimental determination of which has been achieved through the availability of modern measurement techniques [3].

This standard was developed in order to provide methodological basis for the application of the method of acoustic strain gauges to Refine the results of strength calculations of vessels, working under pressure, and to determine the real stress state of the material.

1 Scope

This standard applies to the acoustic method of determining the stress state of the material of cylindrical shells, thin-walled vessels working under pressure, made of carbon and low alloy steels according to GOST R 52630с longitudinal welds.

This standard specifies the basic requirements for the procedure of determining the biaxial stress state of the material of shells with the use of bulk longitudinal and transverse waves propagating normal to the surface of the shell.

Established by this standard method can be applied both in laboratory research and bench and full-scale conditions control the stress state of the material of the thin-walled cylindrical shells of vessels working under pressure.

2 Normative references

This standard uses the regulatory references to the following standards:

GOST R ISO 5725−2-2002 Accuracy (trueness and precision) of methods and measurement results. Part 2. The basic method for the determination of repeatability and reproducibility of a standard measurement method

GOST R 8.625−2006 State system for ensuring the uniformity of measurements. Resistance thermometers of platinum, copper and Nickel. General technical requirements and test methods

GOST R 50599−93 Vessels and apparatus welded steel high pressure. Nondestructive testing in the manufacture and operation of

GOST R 52630−2012 Vessels and apparatus welded steel. General specifications

GOST R 52890−2007 nondestructive testing. Acoustic method of control of stresses in material of pipelines. General requirements

GOST R 55043−2012 nondestructive testing. Determination of the coefficients of elastic-acoustic coupling. General requirements

GOST 7.32−91 System of standards on information, librarianship and publishing. The report on research work. The structure and rules of registration

GOST 12.1.001−89 System safety standards. Ultrasound. General safety requirements

GOST 12.1.004−91 System safety standards. Fire safety. General requirements

GOST 12.1.019−79 System of standards of occupational safety. Electrical safety. General requirements and nomenclature of types of protection

GOST 12.1.038−82 standards System of labor safety. Electrical safety. The maximum permissible values of the touch voltage and currents

GOST 12.2.003−91 System safety standards. Equipment production. General safety requirements

GOST 12.2.013.0−91 (IEC 745−1-82) System of occupational safety standards. Machines manual electric. General safety requirements and test methods

GOST 12.3.002−75 System safety standards. The process of production. General safety requirements

GOST 1497−84 Metals. Test methods tensile

GOST 2768−84 Acetone. Specifications

GOST 2789−73 surface Roughness. Parameters and characteristics

GOST 10587−84epoxy-Dianova uncured. Specifications
________________
Standard operates only on the territory of the Russian Federation.

GOST 17299−78 ethyl Alcohol technical. Specifications

GOST 26266−90 nondestructive testing. The ultrasonic transducers. General technical requirements

GOST 28840−90 Machine for mechanical tests of materials

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 Symbols and abbreviations

3.1 this standard applies the following conventions:

3.2 this standard applies the following abbreviations:

4 General provisions

4.1 Measuring axial and circumferential stresses in the measuring point of OSD execute method of customroot in accordance with the General requirements of GOST R 52890.

4.2 the Method is based on the existing in the field of elastic deformations of a linear dependence of velocity of propagation of bulk elastic waves in the direction perpendicular to the plane of action of the stresses, of mechanical stresses in the axial and circumferential directions.

4.3 thin-walled cylindrical shells subjected to internal pressure, stresses in radial direction are small in comparison with the stresses in axial and circumferential directions. Therefore, the stress state considered locally flat, dependence of velocity of propagation of bulk elastic waves from the radial stresses are neglected.

4.4 For measuring the axial and Hoop stresses under biaxial stress state using the transverse waves polarized in the directions of action of the stresses and longitudinal waves.

The direction of wave propagation is radial (perpendicular to the plane of action of the measured voltages).

4.5 diagram of the testing of the material corresponds to the echo method of ultrasonic testing. Method of excitation of elastic vibrations — pin. The form of the radiated signal is «pulse» with a high-frequency (ultrasonic) filling the envelope smooth and effective duration (at the level of 0.6 of the maximum amplitude) 2−4 period of the fundamental frequency.

4.6 Radiation and reception of acoustic signals provide by using direct combined or separated-combined EAP longitudinal and transverse waves.

Note — as EAP can be used in probes according to GOST 26266 or electroacoustic transducer.

4.7 the Measured voltages are averaged by volume of the ultrasonic beam, determined by the transverse dimensions of the EAP and the thickness of the material. For cylindrical OSD is the principal stresses in the plane perpendicular to the radial direction. Stress values counted from the initial level corresponding to the absence of pressure of the working medium in the SD.

4.8 CWAS used to calculate stresses from the measured acoustic delays are characteristics of the material, determined by the modules of its linear and nonlinear elasticity. Value KOIS for steels PCA must be defined with a maximum relative error of ±10%. Experimental determination of CWAS carried out in accordance with the requirements of GOST 55043* and Annex A of this standard.
________________
* Probably, the error of the original. Should read: GOST R 55043−2012. — Note the manufacturer’s database.

4.9 the Effect of temperature on the measurement results of voltages into account by using thermo-acoustic coefficients, the procedure for determining which is given in Appendix B.

5 safety Requirements

5.1 measurements allow operators with skills of equipment operation ultrasonic inspection, able to use national and industry normative and technical documents on the acoustic control techniques, trained to work with used C and are certified for knowledge of safety regulations in the relevant sector of industry.

5.2 When identifying the NS GSO operator should be guided by GOST 12.1.001, GOST 12.2.003, GOST 12.3.002 and rules of technical safety for operation of electrical consumers according to GOST 12.1.019 and GOST 12.1.038.

5.3 Measurement is carried out in accordance with the safety requirements specified in the operating instructions of the equipment, part of the used SI.

5.4 Facilities for measurements shall meet the requirements [4]* and [5].
________________
* See Bibliography. — Note the manufacturer’s database.

5.5 At the organization of works on determination of the national Assembly of OSD must be met fire safety requirements according to GOST 12.1.004.

6 Requirements for measuring instruments

6.1 as SI can be used installing collected from production equipment, and specialized equipment (hereinafter — the devices) to determine the time intervals between the repeatedly reflected UI, propagating in the material is OK, certified and verified in the prescribed manner.

6.2 SI needs to provide the measurement of the echo method using the UI with a smooth envelope.

6.3 SI needs to provide the possibility of radiation and reception of UI with an effective rate of 2.5 to 10 MHz.

6.4 In the set SI must enter direct combined or separated-combined EAP, which provides radiation and reception of pulses of longitudinal and transverse elastic waves propagating normal to the surface of OSD.

Note — as a direct probe of the combined shear waves can be used converters «Panametrics» (USA).

6.5 Documentation the SI shall contain the measurement procedure and the documents that establish:

— the purpose and scope SI;

— the composition and main characteristics of the hardware and software, including error of measurement of the parameters of the UI;

— methods and means of achieving the compatibility of SI, including data, electrical, energy, software, development, and operational;

rules of aggregation of hardware and software and their interaction.

6.6 description of the functionality of SI in the operational, engineering and programme documents should reflect the specifications of the hardware and software.

6.7 Operational characteristics of the SI must conform to the requirements of the specifications and of this standard.

6.8 Requirements for software of measuring instruments

6.8.1 Software SI shall provide the possibility of selecting any of the reflected UI and search for the required sampling points of the profile of pulses.

6.8.2 Software must consider the conditions of the acoustic measurements at GSO, in particular temperature.

6.8.3 Primary acoustic information for each point of measurement should always be stored on external media, protected from unauthorized access.

6.9 Ancillary devices and materials when using piezoelectric transducers

6.9.1 Grinding tool for surface preparation according to GOST 12.2.013.1.

6.9.2 Degreasing liquid (alcohol according to GOST 17299 or acetone GOST 2768) for surface preparation.

6.9.3 couplant when using probes.

6.9.4 For measuring the surface temperature of OSD use contact thermometers according to GOST R 8.625 with a temperature accuracy of not more than 1 °C in the temperature range from 0 °C to 60 °C.

7 Requirements for building control

7.1 wall Thickness of OSD must be at least 20 times smaller than its diameter.

7.2 Before installation of the EAP surface cleaned of dirt, scale, rust and degreased.

7.3 the Class of surface roughness at the point of measurements using the probe is not lower thanRa 2,5 (GOST 2789).

Note — When using the probe method does not provide the required accuracy of the determination of the national Assembly, if the surface roughness of OSD Ra exceeds 2.5 µm according to GOST 2789.

7.4 Distance from the measuring point to the weld is not less than twice the wall thickness of OSD.

7.5 When using the probe the viscosity of the contact liquid at the temperature of measurement should correspond to the viscosity of the epoxy resin at a temperature of 25°C: 12−25 PA·s (GOST 10587).

8 preparation for measurement

8.1 Study certificates for material of OSD.

8.2 On the basis of technical documentation on «OK «to determine values of h at the measurement points.

8.3 On the basis of reference data or experimentally determine the values of and .

8.4 Choose EAP, the effective pulse frequency which depends on h has the following values:

— when h is from 2 to 3 mm =10 MHz;

— if h from 3 to 10 mm =5 MHz;

— when h exceeds 10 mm =2.5 MHz.

8.5 Identify the location of the measuring points.

8.6 the state of the surface at selected points in compliance with the conditions of measurement (see 7.2, 7.3).

8.7 is Applied, if necessary, the layer of contact liquid on the prepared surface of OSD.

8.8 Install EAP on the surface of OSD, connect them to the device.

8.9 turn on the device, check its performance when displaying video device timebase of the received signals.

8.10 On the screen of a monitor device without any visible distortion shall be observed repeatedly reflected to the TOU.

8.11 Verify the absence on the time scan additional pulses are caused by either having to measure additional reflecting surfaces (valid for operating conditions of SD defect layers, inclusions, etc., detected by ultrasonic testing in accordance with GOST R 50599) or improper orientation of the transducer transverse vibrations relative to the axes of symmetry of the material of OSD.

8.12 calculate the minimum value of the scan, providing visualization of the required number of the reflected UI and measure the delay with a given relative error by the formula:

, (1)

where is the hardware delay of the probe pulse, µs, defined by the technical characteristics of the used SI.

Typically, the value should not exceed a value of 10.

8.13 Get the waveforms of signals when using EAP longitudinal elastic waves when the value of the sweep .

8.14 Estimate the ratio of the amplitude of the pulses of elastic longitudinal wave number to the average of the noise level. If this ratio exceeds 10 dB, the measurements with a given relative error is considered possible.

8.15 If the ratio «signal/noise» for momentum elastic longitudinal wave number is less than 10 dB, then successively reduce the value per unit as long as the value of the ratio «signal/noise» will not be more than 10 dB.

8.16 Calculated actual relative error of determining the delays MI of longitudinal elastic waves according to the formula:

, (2)

and then make a decision about carrying out measurements with a reduced compared to the error or replace a SI more accurate, providing the ratio of

. (3)

8.17 Measurement 8.13−8.16 repeat for the transducer transverse elastic waves, polarized in the axial direction, defining an acceptable number value of the reflected UI , while the actual relative error in determining the delay of UI calculated by the formula

. (4)

Measurements 8.18 8.13−8.16 repeat for the transducer transverse elastic waves, polarized in a circular direction, defining an acceptable number value of the reflected UI , while the actual relative error in determining the delay of UI calculated by the formula

. (5)

Note — set out in 8.1 to 8.18 of the preparation for the measurement is the same for SD at working pressure and at zero pressure.

9 the procedures for measuring and processing the results

9.1 With the help of a contact thermometer to measure the surface temperature of OSD at zero pressure in diabetes .

9.2 In accordance with the user manual of the instrument are measuring the latency of spatial waves , with the reinstallation of EAP. The number of repetitions must be at least 5.

Note — usually, the smallest error in the measurement of delay provides a method of signal transfer through zero [6].

9.3 the Array of values to check for outliers in accordance with GOST R ISO 5725−2.

9.4 After reducing (in the presence of outliers) values for further calculations use a truncated variational series.

9.5 Determine the values and formulas:

, (6)

. (7)

9.6 Check that the condition:

. (8)

9.7 If the condition (8) further calculations using the value obtained in 9.5.

9.8 If the condition (8) is not fulfilled, a second measurement with the increased number .

9.9 If the increase in the number of measurements does not lead to fulfillment of the condition (8) adopt the decision on the further measurements with reduced accuracy.

9.10 Measurement processing* 9.2−9.9 EAP is carried out for shear waves with polarization in the axial direction. At the same time determine the values and formulas
________________
* The text of the document is matched against the original. — Note the manufacturer’s database.

, (9)

. (10)

9.11 Measurements and processing at 9.2−9.9 EAP is carried out for shear waves with polarization in the annular direction. At the same time determine the values and formulas:

, (11)

. (12)

9.12 Expect delays given by the formulae:

, (13)

, (14)

. (15)

9.13 using a contact thermometer to measure the surface temperature of OSD under operating pressure, diabetes, Etc

9.14 Measurements and their processing for 9.2−9.13 conduct for GSO under operating pressure, diabetes.

9.15 Shows the delay calculated by the formulas:

, (16)

, (17)

. (18)

9.16 Voltage and for each point of measurement is calculated according to the formulas:

, (19)

, (20)

where , , , ,

, .

10 Rules for registration of measurement results

10.1 the results of the measurements are fixed in the Protocol, the form of which is given in Appendix V.

10.2 If the dimension NS of OSD are part of the research work, the measurement should be made in accordance with the requirements of GOST 7.32.

Annex a (mandatory). Definition provocations coefficients

Appendix A
(required)

A. 1 Provocations coefficients determined by conducting tensile tests on flat samples according to GOST 1497.

A. 2 Use two types of samples:

— longitudinal cut from the material of OSD parallel to the weld seam;

— a cross-cut from the material of OSD perpendicular to the weld seam.

A. 3 the Class of surface roughness of samples at the point of measurements — not less than Ra 2.5 churchyard 2789.

A. 4 For loading sample use of machines for mechanical testing of materials according to GOST 28840.

A. 5 Selection of test equipment is carried out so that the sample to create a voltage gap of 0,8.

A. 6 the Testing machine must provide the necessary load with an acceptable voltage deviation not more than 1 MPa during the period of time required to conduct acoustic measurements (from 30 seconds to several minutes depending on the skill of the operator and used by the SI).

A. 7 form the step of loading the sample from the initial load corresponding to the value of uniaxial tension of not more than 0.1, until a load corresponding to 0.8. It is recommended to provide at least five levels of loading for the subsequent regression analysis of test results.

A. 8 Sample with the attached EAP put into the machine for mechanical tests, achieve proper alignment and attached to it a small load to ensure reliable fixation of the specimen in the grips.

9 A. At each step of loading are measuring delays of the three types of UI:

 — delay MS for shear wave, polarized along the axis of loading;

-delay MS for shear wave, polarized perpendicular to the axis of loading;

 — delay MS for longitudinal waves.

Note — Measurements are conducted with increasing and decreasing load. Then the specimen is removed from the car. Each loading (up-down) is carried out three times. Before the new loading EAP remove and re-install on the sample.

A. 10 Conduct regression dependency handling , ,

where , ;

, ,  — delays UI in the material of the specimen without load.

A. 11 Customplugin coefficients determined in the following way:

equal to the tangent of the angle of inclination to the axis of the regression lines for the longitudinal samples;

equal to the tangent of the angle of inclination to the axis of the regression lines for the longitudinal samples;

equal to the tangent of the angle of inclination to the axis of the regression line for control samples;

equal to the tangent of the angle of inclination to the axis of the regression line for control samples.

A. 12 Provocations coefficients calculated by the formulas:

, , , . (A. 1)

Appendix B (mandatory). Determination of thermo-acoustic coefficients

Appendix B
(required)

B. 1 Definition of thermoacoustic coefficients (, ) is performed on the basis of the study of regression dependences of the delays of pulses of elastic waves of the respective types of the temperature T of the control sample.

B. 2 measurement of the temperature dependences is carried out on control samples of material of OSD in the laboratory.

B. 3 the surface Temperature of the sample is measured using a contact thermometer according to GOST R 8.625.

B. 4 the Sample is heated to a temperature of 80 °C, then for a uniform temperature distribution maintained at room temperature until they cool down to 60 °C.

B. 5 as the cooling of the sample at intervals of 5 °C is carried out temperature measurement of the sample surface and the corresponding delays for each th* temperatures.
________________
* The text of the document matches the original. — Note the manufacturer’s database.

B. 6 Thermoacoustic coefficients calculated by the formula:

, (B. 1)

where ;

the total number of measurements for a given sample.

Note — the Measurement is repeated for three to five samples averaged results.

Annex b (recommended). Form of measurement Protocol

The App
(recommended)

PROTOCOL
determine the stress state of the shell of the pressure vessel

Bibliography

The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: STANDARTINFORM, 2015