GOST 31244-2004

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  ГОСТ 31244-2004

GOST 31244−2004 nondestructive testing. Evaluation of physico-mechanical characteristics of the material elements of technical systems using the acoustic method. General requirements

GOST 31244−2004
Group Т59

INTERSTATE STANDARD

Nondestructive testing

EVALUATION OF PHYSICO-MECHANICAL CHARACTERISTICS OF THE MATERIAL ELEMENTS OF TECHNICAL SYSTEMS ACOUSTIC METHOD

General requirements

Non-destructive testing. Evaluation of material physical and mechanical properties for technical system elements by acoustic method. General requirements

ISS 77.040.10
AXTU 0009

Date of introduction* 2010−04−01

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* The same for all listed in the Preface States.

Preface

Goals, basic principles and main procedure of works on interstate standardization have been established in GOST 1.0−92 «interstate standardization system. Basic provisions» and GOST 1.2−97* «interstate standardization system. Interstate standards, rules and recommendations on interstate standardization. The procedure of development, adoption, application, renewal and cancellation"
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* On the territory of the Russian Federation GOST 1.2−2009. — Note the manufacturer’s database.

Data on standard

1 DEVELOPED by the Open joint-stock company «Scientific-research center of control and diagnostics of technical systems» on the basis of their own authentic translation of the standard referred to in paragraph 4

2 as AMENDED by the Federal Agency for technical regulation and Metrology

3 ACCEPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 25−2004, dated may 26, 2004)

The adoption voted:

4 by Order of the Federal Agency for technical regulation and Metrology of December 15, 2009 N 1000-St inter-state standard GOST 31244−2004 introduced as a national standard of the Russian Federation from April 1, 2010

5 INTRODUCED FOR THE FIRST TIME


Information about introduction in action (termination) of this standard is published in the index «National standards».

Information about the amendments to this standard is published in the index «National standards», and the text changes — in the information sign «National standards». In case of revision or cancellation of this standard the appropriate information will be published in the information index «National standards»

1 Scope

This standard applies to a pulsed active acoustic methods used to measure physico-mechanical characteristics of the material elements of technical systems.

The standard applies mainly to metallic materials.

The standard can be used to assess those physical and mechanical characteristics for which the preliminary research established that there is a regression relations with the acoustic parameters.

The standard establishes General requirements for acoustic control and procedure of application of acoustic methods in problems of determination of physical-mechanical characteristics of the material elements of technical systems.

Standard REGLEMENTARE the order of evaluation of physico-mechanical characteristics of the material elements of technical systems based on the use obtained in the course of the training experiments of the dependency of acoustic parameters from the determined physical-mechanical characteristics.

Note — Under the training experiment understand a complex experimental research, in which establish the coefficients of regression relations of the acoustic parameters and the physical-mechanical characteristics of the material of the controllable elements of the technical system.


This standard applies to products (machines) and their parts that are objects of technical diagnostics.

2 Normative references

The present standard features references to the following international standards:

GOST 8.315−97 State system for ensuring the uniformity of measurements. Standard samples of composition and properties of substances and materials. The main provisions of the

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

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

GOST 1497−84 Metals. Test methods tensile

GOST 20911−89 Technical diagnostics. Terms and definitions

GOST 23829−85 nondestructive testing acoustic. Terms and definitions

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

Note — When using this standard appropriate to test the effect of reference standards and codes in the state according to the corresponding index of standards and codes, made as of January 1 of the current year and related information signs, published in the current year. If the reference document is replaced (modified), then the use of this standard should be guided by replacing (amended) standard. If the reference document is cancelled without replacement, then the situation in which the given link applies to the extent that does not affect this link.

3 Reduction

In this standard, the following abbreviations apply:

SAK — system acoustic control;

OK — the object of control;

SK — means of control;

AO hardware;

IN software;

MO — technical support;

EAP — electro-acoustic transducer.

4 General provisions

4.1 Acoustic monitoring methods based on the sensitivity of parameters of elastic waves propagating in the material element of the technical system, to the structural and mechanical condition of the material.

4.2 as acoustic parameters used are the speed of sound, attenuation coefficients and related parameters of elastic waves of various types.

4.3 the Need to assess the physico-mechanical characteristics of the material elements of technical systems, acoustic methods and its frequency set depending on the requirements of technical documentation.

4.4 Procedure for the evaluation of physico-mechanical characteristics of the material element of the technical system is performed in the following order:

— the choice of acoustic parameters that are sensitive to the change of physico-mechanical characteristics of the material of controlled elements of technical systems;

— establishing regression relations of acoustic parameters of the material with its physical and mechanical characteristics in the course of teaching experiments;

— evaluation of physico-mechanical characteristics of the material element of the controlled technical system.

5 the requirements of the building control

5.1 Surveyed the elements of the technical systems in the areas of control must not contain any macro defects detected by nondestructive methods.

5.2 surface Condition in control areas should provide the necessary sensitivity and stability the sensitivity of the informative acoustic parameters, established during training experiments.

5.3 If inspection is OK with curved surfaces is more preferable to control the surface are the convex type.

5.4 Allowable range of the thickness of material in the zone of control is determined on the basis of the values of the attenuation coefficient of the waves is set on the basis of reference data or during training experiments.

5.5 the Minimum radius of curvature and the degree of not parallel surfaces of the structural element in the area of control is determined depending on the values of the maximum permissible error of measurement used acoustic parameter.

6 Requirements for acoustic control

6.1 SAK is in accordance with GOST 20911 set of OK, SK, normative-technological documentation and the human operator.

6.2 SC is formed on the basis of JSC, (if necessary) and MO.

6.3 as JSC IC can be used installing collected from the production equipment and the original blocks, verified in the prescribed manner in accordance with the schemes indicated in the recommendations [1], [2], [3] depending on the used type of elastic waves, and provides:

— receiving the acoustic parameters that are directly used for estimating physico-mechanical characteristics of the material OK.

— receiving the acoustic information used as input for processing means.

6.4 Requirements for the permissible error of the measuring equipment JSC IC and the procedure for its evaluation

6.4.1 On the basis of information about changing an acoustic parameter within the controlled change of physical and mechanical characteristics , existing or received as a result of the first of a series of training experiments, choose the method and means of measurement providing the highest sensitivity to , i.e., leading their use to maximize value

, (1)

where , maximum and minimum values of the acoustic parameter;

,  — the maximum and minimum values of determined physico-mechanical characteristics.

6.4.2 Minimum value of the absolute error of measurement of the acoustic parameterdetermined by the formula

, (2)

where is the absolute error of measurement physical and mechanical characteristics.

6.4.3 the Value of the permissible error of the measuring equipment JSC IC should satisfy the condition

, (3)

where quality stock.

6.5 prerequisites of JSC IC are EAP and standard samples.

6.6 Requirements for EAP

6.6.1 as EAP in the SAC is allowed to use any converters. Typically use a piezoelectric transducer.

6.6.2 design of the piezoelectric transducers must comply with the General ergonomic requirements GOST 26266.

6.6.3 Shape of the working surface of the piezoelectric transducer and its dimensions are selected on the basis of geometric features OK.

6.6.4 Method of input of ultrasound in a controlled material (pin, slotted, non-contact, immersion) is determined based on the characteristics of the geometry OK, and the requirements of the control technology.

6.6.5 in the contact mode of input of ultrasound as a contact lubricant is recommended to use a good wetting of the contact surface, the liquid does not cause corrosion OK.

6.7 Requirements for standard samples

6.7.1 For the preparation of JSC IC measurements used standard samples, meet the requirements of GOST 8.315 and employees for setting up equipment and conducting a series of training experiments.

6.7.2 Standard samples made from material intended OK in the initial state in accordance with the requirements of GOST 8.315. Surface quality of standard samples must be identical to the surface OK. The identity shall be checked instrumentally assess the roughness and waviness (in increments of 5−10 wavelengths of the ultrasonic wave) of the surface.

Notes

1 note that the roughness has a 10% to 20%, and the waviness is from 80% to 90% influence on the stability of the sensitivity of the informative acoustic parameters.

2 use as standard samples of cuttings from the investigated elements OK.

6.7.3 Measurements on standard samples is carried out under conditions matching the conditions of the measurements OK.

Note — subject to the availability of appropriate correlations measurements in normal climatic conditions:

6.8 Software controls

6.8.1 program should include routines that support self-diagnosis system.

Note — self-diagnostic system includes an acoustic path.

6.8.2 Shall be provided the possibility of rapid replenishment of the data Bank of the system by the introduction of information obtained in the course of the training experiments and the result of another survey OK.

6.8.3 the Algorithmic part of the software should provide the calculation of the acoustic parameters with the error specified in 6.4.

6.8.4 Software needs to take into account the conditions of carrying out acoustic measurements on «OK», in particular, temperature.

6.8.5 Primary acoustic information for each zone of control must reside on external media, protected from unauthorized access.

6.9 MO SK must contain the documents establishing:

— the purpose and scope of the insurance;

— the composition and main characteristics of funds of JSC, which includes the norm of measurement error of the acoustic parameter control;

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

— rules for the aggregation of assets of JSC and organizations of their interaction.

6.10 description of the functionality of SC in operational, design and policy documents OK and SK should contain the specifications of the hardware and software.

6.11 To conduct acoustic measurements to assess physical and mechanical characteristics OK permitted professionals with skills of operation of ultrasonic flaw detection equipment and with appropriate qualification certificates.

7 preparations for the control

7.1 Preparation for control consists of the following main stages:

— analysis of the technical documentation and mapping surveys;

— a set of teaching experiments;

— prepare the object to the acoustic measurements.

7.2 the Order of analysis of the technical documentation and mapping surveys

7.2.1 On the basis of technical documentation analyze:

— materials of the object (physical-mechanical characteristics, heat treatment);

— types of connections;

places structural transitions;

— types of stress state of structural elements;

— operating conditions.

7.2.2 the analysis of failures of structural elements are fixed:

— causes of failures;

— place of failure;

— ability to change the structure and physico-mechanical characteristics of the material in the zone of failure.

7.2.3 on the Basis of the measured physico-mechanical characteristics choose the most informative acoustic parameter.

7.2.4 On the basis of the analysis carried out in accordance with 7.2.1−7.2.2 and subject to the requirements of section 6 maps acoustic control object.

7.3 the Procedure for conducting the training experiments

7.3.1 Based on the operating conditions of the object and nature of defined physico-mechanical characteristics choose the range of changes of external influences (temperature, load, strain, etc.).

7.3.2 outline of the experiment so that each parameter external influences have been implemented at least five States of the material.

Example — Under the control of plastic deformation by active deformation of standard samples implement the five values of residual deformation; in the evaluation of the grain size by an appropriate heat treatment to form structures with five different values of average grain size, etc.

Note — the state of the material should be taken into account that the most probable state of the material is OK you must be in the middle of the sample.

7.3.3 taking into account the structural characteristics of the material OK choose the types of transducers used and their frequency.

7.3.3.1 the Type of elastic waves depends on the nature of the solved engineering problems.

7.3.3.2 Frequency converters used depend on the grain size of the material is OK and used acoustic parameters:

— when used as an acoustic parameter in the sound speed and related parameters are recommended when choosing a frequency Converter to provide the following relationship between the wavelength of the emitted wave and the average grain size of the material :

;

— when used in an acoustic parameter of the attenuation coefficient and related parameters is recommended to provide the following relationship between the wavelength of the emitted wave and the mean characteristic grain size of the material ;

.

7.3.4 Based on the characteristics of the geometry and operating conditions OK link a setting to define the selected acoustic features.

7.3.5 In each state spend the necessary acoustic measurements with registration of the selected acoustic parameters or arrays of primary acoustic information depending on the AO SK.

Note — When using the output of the primary arrays of acoustic information in each condition of the material of the standard samples, the arrays should be processed by means of MO SAK to obtain the necessary acoustic parameters.

7.3.6 Establish a regression when the selected acoustic parameter with the studied physical-mechanical characteristics of the material OK, and make a derived relationship coefficients in a data Bank SAK.

7.4 preparation of the object for acoustic measurements

7.4.1 control Zones should be numbered.

7.4.2 Should be satisfied the requirements of section 5.

8 performance of control

8.1 Measure and bring in a map of acoustic control the temperature OK in the control areas, as well as the current pressure.

8.2 carry out the refining of the calculation algorithm:

— on a standard sample is carried out setting of JSC IC;

— extracted from the data Bank SAK, the respective coefficients of regression relationships;

— expect the measured physical-mechanical characteristics for the standard sample;

— compare the obtained value with the value stored in the data Bank;

— makes appropriate amendments to the calculation algorithm.

8.3 In accordance with the map of the survey in the selected areas is carried out a set of acoustic measurements and record their results.

8.4 Counting the most informative acoustic parameter.

8.5 the Measure at 8.3−8.4 is repeated 3−5 times.

8.6 Estimate the variance of the most informative acoustic parameter and compare it with the corresponding value obtained during the training experiment on a standard sample.

8.7 If necessary, increase the number of repetitions as long as the variance of the most informative acoustic parameter will not be comparable to the variance obtained during the training experiment.

8.8 average is the most informative acoustic parameters determine the necessary physical-mechanical characteristics of the material, using relevant information from the data Bank.

9 presentation of results control

9.1 the Results of the control 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) must be installed in the technical documentation for the control.

9.2 the results of the survey should be maintained until the next control OK.

10 security Requirements

10.1 During the work on determination of physical and mechanical characteristics of the acoustic method, 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.

10.2 Work should be carried out in accordance with the safety requirements set out in the operating instructions of the equipment that is part of the UK.

10.3 the methodology of acoustic measurements to control a specific element of the technical system must be specified requirements, observance of which is obligatory when working with control objects in the enterprise.

10.4 In the organization of control must be complied with fire safety requirements according to GOST 12.1.004.

Annex a (recommended). Form log the definition of physico-mechanical characteristics of the material elements of technical systems acoustic method

Appendix A
(recommended)

Bibliography