GOST R 55043-2012

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  ГОСТ Р 55043-2012

GOST R 55043−2012 nondestructive testing. The coecients provocational connection. General requirements

GOST R 55043−2012
Group Т59

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Nondestructive testing

THE COECIENTS PROVOCATIONAL CONNECTION

General requirements

Non-destructive testing. Evaluation of elastic-acoustic coefficients. General requirements

OKS 77.040.10

Date of introduction 2014−01−01

Preface

1 DEVELOPED by the Nizhny Novgorod branch of Federal state institution of science Institute of machines science named… Blagonravova Russian Academy of Sciences (IMASH NF) and the Autonomous nonprofit organization «Scientific-research center of control and diagnostics of technical systems» (ANO «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 8 November 2012 No. 699-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 the upcoming issue of the monthly 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

In using acoustic methods for determining the stress state of materials and structures lies provocations effect — the linear dependence of elastic wave velocities, stress, a reliable experimental determination of which has become possible with the advent of modern ultrasonic and electronic measuring equipment.

The coefficients provocations ties between the acoustic parameters and mechanical stress. In this standard the procedure of determining the values of the coefficients of provocations when solids based on experimental determination of the coefficients kostopoulou communication in the process acoustomechanical tests, including precision measurements of the acoustic parameters of the material known in his stressed state, namely, uniaxial tension or compression.

The standard can be used in acoustomechanical tests of structural materials used in various industries, as well as promising new materials with unknown acoustic properties.

Materials classified by the parameter of intrinsic acoustic anisotropy, is caused by the anisotropy of their elastic properties. Depending on the value of this parameter recommended various ways of determining the values of the coefficients provocational connection.

This standard will serve as methodological basis for application of the acoustoelasticity method for solving a class of mechanical and diagnostic problems that require experimental evaluation of the stress state of materials, industrial structures and objects.

1 Scope

This standard applies to the experimental determination of the coefficients provocational connection of structural materials, characterizing the sensitivity of the acoustoelasticity method to mechanical stresses in the material. These coefficients are used in non-destructive testing to determine the single and biaxial principal stresses acting in the plane perpendicular to the direction of wave propagation, isotropic and anisotropic material, the directions of principal stresses which coincide with the axes of symmetry (including the sheet metal where the stresses acting along and across the rolled).

The standard does not apply to the determination of residual stresses arising in irreversible changes of the material due to heat treatment, plastic deformation, fatigue damage accumulation, etc.

This standard specifies the procedure for determining the coefficients provocational connection material technical objects with the use of standard samples exposed in laboratory conditions, known by the sign and magnitude of the stresses, homogeneous in volume of the material being studied.

2 Normative references

This standard uses the regulatory references to the following standards:

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

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

GOST 25.503−97 Metals. Calculations and strength tests. Methods of mechanical testing of metals. Method of compression testing

GOST 1497−84 Metals. Test methods tensile

GOST 2789−73 surface Roughness. Parameters and characteristics

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 designations:

3.2 this standard applies the following abbreviations:

4 safety Requirements

4.1 measurements allow operators with skills of operation of the ultrasonic control equipment that can use the standards and 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.

4.2 in the works, by definition, COIS material the 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 installations, approved by Gosenergonadzor.

4.3 Work should be carried out in accordance with the safety requirements set out in the instruction manual of equipment, part of the used SI.

4.4 When carrying out acoustomechanical tests using a specific testing machine (bench for mechanical testing) must meet the security requirements outlined in the instruction manual and adopted in the testing laboratory (area of testing machines).

5 Requirements for measuring instruments

5.1 as SI can be used installing collected from production equipment, and specialized instruments to determine the stress acoustic (ultrasonic) method, certified and verified in the prescribed manner.

5.2 SI needs to provide the measurement of the echo method using acoustic pulses with a smooth envelope.

5.3 In set SI have to log EAP, providing the emitting and receiving pulses of shear and longitudinal elastic waves propagating normal to the material surface.

5.4 On the basis of information about the value of the coefficient of material use of SI for which permissible absolute error of measurement of delay satisfies the condition

, (1)

where metrological stock whose value is in the range from 3 to 5;

 — the maximum value of the absolute error of measurement of delay , calculated according to the formula

, (2)

where is the absolute error of determination of COUSE ;

permissible absolute error of voltage measurement.

5.5 Requirements for software of measuring instruments

5.5.1 Algorithmic part of the software should provide the calculation of the delay pulses with an accuracy in accordance with 5.4.

5.5.2 Software must consider the conditions of the acoustic measurements, particularly temperature.

5.5.3 the Primary acoustic information for each test should always be stored on external media, protected from unauthorized access.

5.6 Requirements for methodological support of measuring instruments

5.6.1 Methodological support SI must 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 rules on measurement error of delay pulses;

— 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.

5.6.2 description of the functionality of SI in the operational, design and program documents of C should reflect the specifications of the hardware and software.

6 sample Requirements for testing

6.1 To conduct acoustomechanical testing of materials used two kinds of known stress state: uniaxial tensile stress and (or) uniaxial compressive stress.

6.2 the Class of surface roughness of the samples under EAP — not below 2,5 according to GOST 2789.

6.3 When conducting the tensile tests used flat samples according to GOST 1497.

6.4 Along with the requirements of GOST 1497 should observe the following recommendations for conducting precision acoustic measurements while loading the sample.

6.4.1 For the resolution of acoustic pulses to the specimen thickness, it is recommended to use samples of structural materials with a thickness of 8−10 mm, but not less than 5−6 mm.

6.4.2 purpose of exception of reverb and transverse resonances across the width of the sample it should be at least three transverse dimensions of the EAP.

6.5 For testing compression material used two types of samples.

6.5.1 universal Flat samples for testing in tension and compression, and meet additional guidelines:

to prevent buckling, and the occurrence of bochkoobraznoj at loading select the cross-sectional shape, as close to square;

— the ratio of the length of the working part and the cross sectional area is selected from the conditions should be not less than three transverse dimensions of the EAP.

6.5.2 Samples for testing compression-only needs to satisfy the requirements for samples of type II according to GOST 25.503. must be at least three transverse dimensions of the EAP.

7 requirements for the test equipment

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

7.2 Choice of test equipment is carried out in such a way that the sample to create tension, amounting to 0,6−0,8, and to ensure conditions for the implementation of precision acoustic measurements 6.4.

7.3 For testing samples generic type use machines that allow both full extension and compression of the material. In this case, it is desirable to use the same sample of material made in accordance with the requirements of 6.4 and 6.5.

7.4 samples were tested in compression using the press and other test equipment that meets the requirements of 7.2. This should take into account that for many materials under compression exceeds the tensile.

7.5 Testing machine should provide the necessary load with an acceptable voltage deviation not more than 1 MPa during the time interval required for the acoustic measurement (the value of this gap depends on the skill of the operator and used by SI).

8 preparation for testing

8.1 In preparation for the test should be performed analysis of technical documents and certificates on the material to identify the brands and technologies of material processing and determine its mechanical characteristics (tensile strength) at the documentation or by conducting mechanical testing.

8.2 define a value with an error not exceeding 0.1%. Base measurements (the absolute value of the delays of shear waves) in the evaluation of acoustic anisotropy parameter should not be less than 50 µs. If this is not possible, then you must make sure that the absolute measurement error did not exceed 0.1%.

8.3 Manufacturer samples for testing

8.3.1 For a weakly anisotropic material (less than 1%) made at least 3 samples in accordance with the requirements of 6.2 to 6.5.

8.3.2 For highly anisotropic material (over 1%) made at least 3 samples cut along and across the direction of symmetry axes of an orthotropic material.

Note — In cases when the class of symmetry of the elastic properties of the material different from the above, the decision on the number of samples is taken empirically.

8.3.3 mechanical properties of the material and the dimensions of the samples choose test equipment in accordance with section 7.

8.3.4 keep the speed of loading of 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.

9 Order of testing

9.1 the 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.

Note — the tests for compression pre-load to make no need.

9.2 At each stage of loading are measuring delays of pulses of elastic waves propagating through the material normal to the sample surface, as by increasing and decreasing the 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.

9.3 For each step of loading measured delays of shear waves polarized along and across the direction of load application, as well as the delay of a longitudinal wave propagating through the material normal to the sample surface. Database of measurements of shear waves at 8.2 for longitudinal waves is at least 30 µs.

9.4 permitted as measurements for all three types of waves simultaneously, and separately for each type of wave. The first option is preferable, however, needs to be satisfied 6.4.2 and 6.5.1 and 6.5.2 given the fact that the measuring area should be in the middle of the sample and the distance between each gripper and this area should not be less than the width of the specimen.

9.5 the Results of acoustic measurements with all the properties of the material, and received in determining its own anisotropy of the material, contribute to the magazine tests, the form of which is given in Appendix A.

10 Handling of test results

10.1 Calculate the coefficients of the linear regression of the dependency values (1, 2, 3 for the relevant wavelengths) from the corresponding values of stresses using the method of least squares. KAUS are the tangents of the angle of inclination to the axis of dependence .

10.2 the Coefficient of correlation dependencies must be not less than 0.9. Dependency , allowed the correlation coefficient is at least 0.8.

Note — To avoid significant errors in experimental determination of the values of KOIS the results acoustomechanical tests it should be borne in mind that for basic materials the coefficient is negative and has the greatest absolute value coefficient , and the coefficient . Values and positive.

10.3 Definition COIS for weakly anisotropic material

10.3.1 COIS weakly anisotropic material is calculated by the formula:

for biaxial NS

; ;

for uniaxial NS

, .

10.3.2 Determine the mean values of KOIS on measurements on three samples and the magnitude of the variations.

10.4 Definition COAS for a highly anisotropic material

10.4.1 COAS strongly anisotropic material is calculated by the formula:

for biaxial NS

, , ,

where ,  — average values of the coefficients kostopoulou regard, the results of measurements on samples cut along and across the rolling, which is calculated by the formula:

, ;

for uniaxial NS

, .

Note — the Sign «» means the direction along the rolling sign «» — across hire (for materials, manufactured products).

11 the results of the tests

11.1 test Results record in the journal, the form of which is given in Appendix A.

Additional information to be logged, the order of registration and storage of the journal (or conclusion) should be used in technical documents to the test.

11.2 If acoustomechanical tests are part of the research work, the measurement should be made in accordance with the requirements of GOST 7.32.

Annex a (recommended). Form of the journal of experimental determination of the values of COIS material

Appendix A
(recommended)

The electronic text of the document
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the official publication of the
M.: STANDARTINFORM, 2014