GOST R 55042-2012
GOST R 55042−2012 nondestructive testing. Determination of thickness of metallic coatings by the acoustic method. General requirements
GOST R 55042−2012
Group Т59
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Nondestructive testing
DETERMINATION OF THICKNESS OF METALLIC COATINGS BY ACOUSTIC METHOD
General requirements
Non-destructive testing. Evaluation of metallic coating thickness by ultrasound. General requirements
OKS 77.040.10
Date of introduction 2014−01−01
Preface
The objectives and principles of standardization in the Russian Federation established by the Federal law of 27 December 2002 N 184-FZ «On technical regulation», and rules for the application of national standards of the Russian Federation — GOST R 1.0−2004 «Standardization in the Russian Federation. The main provisions"
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* On the territory of the Russian Federation the document is not valid. Valid GOST R 1.0−2012, here and hereafter. — Note the manufacturer’s database.
Data on standard
1 DEVELOPED by Autonomous non-commercial organization «Scientific-research center of control and diagnostics of technical systems» (ANO «nits KD»), the Nizhny Novgorod branch of Federal state institution of science Institute of machines science named… Blagonravova Russian Academy of Sciences (NF IMASH)
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
Almost all industries use different metal coating deposited on the surface of technical objects. In cases where coatings are applied to the surface of the potentially dangerous technical objects, increased requirements to the allowable error of the thickness of the coatings. It refers to the hardening and in particular to restorative coatings.
In accordance with GOST 27750 determination of the thickness of the coating is carried out by the following methods: magnetic method (magnetic flux ponderomotive method and induction method), eddy current, thermoelectric and ionizing radiation.
The main disadvantage of magnetic methods is the requirement of the sharp differences in magnetic properties of materials (it must be ferromagnetic) and coatings that are not in all cases.
The greatest application of eddy current method has been to determine the thickness of non-metallic coatings on the basis of non-ferrous metals. When used to determine the thickness of coatings deposited on the base of ferrous metals with non-normalized electric resistance, there is an unacceptably large error.
The thermoelectric method has a high error not allowing it to be used to determine the thickness of the coating elements on the surface, responsible of technical objects, and the method of ionizing radiation is not widely spread because of increased security requirements.
This standard is designed to provide a methodological basis for the application of the acoustic method of determining thickness of metal coatings on metal bases with any combination of magnetic and electric properties of materials of coating and base.
1 Scope
This standard applies to the acoustic method of determining thickness of metal coatings on metal bases.
The standard establishes the basic requirements to the procedure of determining the thickness of coatings using surface acoustic Rayleigh waves propagating along the surface of the test object coated with a metal coating having good adhesion to base material.
Installed standard method can be applied both in laboratory studies and operation of technical objects for various purposes.
2 Normative references
This standard uses the regulatory references to the following standards:
GOST 8.362−79 State system for ensuring the uniformity of measurements. Thickness measurement of coatings. Terms and definitions
GOST 9.008−82 unified system of protection from corrosion and ageing. Coating of metallic and non-metallic
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* the System of occupational safety standards. Electrical safety. General requirements and nomenclature of types of protection
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* On the territory of the Russian Federation the document is not valid. Valid GOST R 12.1.019−2009, here and hereafter. — Note the manufacturer’s database.
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
GOST 12.3.002−75 System safety standards. The process of production. General safety requirements
GOST 32−74 Oil turbine. Specifications
GOST 2768−84 Acetone. Specifications
GOST 2789−73 surface Roughness. Parameters and characteristics
GOST 6259−75 Reagents. Glycerin. Specifications
GOST 6616−94 thermoelectric Converters. General specifications
GOST 6651−94* Thermal resistance. General technical requirements and test methods
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* On the territory of the Russian Federation the document is not valid. Valid GOST 6651−2009, here and hereafter. — Note the manufacturer’s database.
GOST 17299−78 ethyl Alcohol technical. Specifications
GOST 26266−90 nondestructive testing. The ultrasonic transducers. General technical requirements
GOST 27750−88 nondestructive testing. Cover recovery. Methods to control the coating thickness
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 published annually by the information sign «National standards» published as on January 1 of the current year, and on relevant issues published monthly information index «National standards», published in the current year. If the reference standard is replaced (changed), when using this standard should be guided by replacing (amended) standard. If the reference standard is cancelled without replacement, then the situation in which the given link applies to the extent that does not affect this link.
3 Terms, definitions, symbols and abbreviations
3.1 this standard applies the terminology and definitions 8.362 according to GOST and GOST 9.008.
3.2 this standard applies the following designations:
| — the speed of propagation of surface acoustic Rayleigh waves in the substrate material, km/s; | |
| — the speed of propagation of surface acoustic Rayleigh waves in the coating material, km/s; | |
| — coating thickness, microns; | |
| — maximum permissible absolute error of determining the coating thickness, µm; | |
| effective pulse frequency of the surface acoustic waves of Rayleigh, MHz; | |
| — the result of a single measurement pulse delay of surface acoustic Rayleigh waves at selected points of a measurement surface; | |
| — the number of measurements of pulse delay of surface acoustic Rayleigh waves at selected points of a measurement surface; | |
| — average delay of a pulse of surface acoustic Rayleigh waves at selected points of measurements of the coating, NS; | |
| — provides a delay pulse of surface acoustic Rayleigh waves at selected points of measurements of the coating, NS; | |
— the temperature at which the measured delay | |
| — average delay of a pulse of surface acoustic Rayleigh waves in the material of the base metal of the structural element, NS; | |
| — provides a delay pulse of surface acoustic Rayleigh waves in the substrate material, NS; | |
— the temperature at which the measured delay | |
| — length of surface acoustic Rayleigh waves in the material of the coating, µm; | |
| — thermoacoustic coefficient equal to the relative change of the pulse delay of Rayleigh wave when the temperature changes by 1 °C 1/ °C. |
3.3 this standard applies the following abbreviations:
| TP | — the thickness of the coating; |
| PAR | — surface acoustic wave of Rayleigh; |
| PEP | — piezoelectric transducer; |
| SI | — a means of measurement. |
4 General provisions
4.1 Method based on the fact that at different velocities PVR in the materials of coating and base effective speed PAR in a constructive element with a thin (100 µm) coating depends on TP [1]-[3].
4.2 the Method is implemented by the manual method of ultrasonic contact testing with the use of dual probe according to GOST 26266.
4.3 Optimal transmitted signal — «microburst» of 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.
4.4 Define TP is averaged over the path of propagation of pulse PAR.
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 in determining TP, 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 consumers according to GOST 12.1.019 and GOST
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 in [4] and [5].
5.5 At the organization of works on determination of TP must be met fire safety requirements according to GOST
6 Requirements for measuring instruments
6.1 as SI apply collected from production equipment, or specialized ultrasonic devices (hereinafter the devices) are certified and verified in the prescribed manner.
6.2 SI needs to ensure that the relative error in determining the pulse delay of PAWR not more than 10.
6.3 Operational characteristics of the devices shall conform to the requirements of the specifications and of this standard.
6.4 as the probe uses pitch-catch piezoelectric transducer of the type П122 according to GOST 26266, consisting of combined in one housing of the emitter and receiver of longitudinal waves.
6.5 To measure the temperature of the surface of the coating using contact thermometers according to GOST 6651 or GOST 6616 type TK with the temperature measurement error is not more than 1 °C in the temperature range from 0 °C to 60 °C.
6.6 Auxiliary devices and materials
6.6.1 Grinding tool for surface preparation of coatings according to GOST
6.6.2 For degreasing surfaces used alcohol according to GOST 17299 or acetone churchyard 2768.
6.6.3 as the contact liquid used is thick enough fluid, good ultrasound conducting fluid (e.g., glycerin according to GOST 6259; autoly 6, 10, 18; compressor and other similar oil according to GOST 32 having wetting properties with respect to coating surface and the contact surface of the probe).
7 coating Requirements
7.1 surface shall not have cracks, chips, delaminations, blisters, open and closed shells, as well as surface contamination.
7.2 TP must be greater than the surface roughness of the surface of the base material.
7.3 as the substrate material can be magnetic and non-magnetic materials: steel and iron-based alloys; alloys based on copper, aluminum, titanium, Nickel etc.
7.4 surface Roughness of the coating — according to GOST 2789 and should comply with the design documentation.
Note — the Method does not provide the required accuracy of definition of TP, if the surface roughness of the coating exceeds 2.5 µm according to GOST 2789.
7.5 Thickness of the base in the measurement zone should be at least 2 mm.
7.6 surface Temperature of the coating in the area of measurement must be in the range from 0 °C to 60 °C.
7.7 Before installing the probe the surface cleaned of dirt, scale, rust and degreased.
8 preparation for measurement
8.1 Establish a maximum permissible absolute error of determination of TP .
8.2 Choosing AEDs, the effective pulse frequency which, depending on has the following values:
— at 2.5 MHz
— at 5,0 MHz,
— when 10 MHz
8.3 On the basis of reference data or experimentally determined values ,
,
.
8.4 Identify the location of the measuring points TP.
8.5 the Dimensions of these zones have one and a half times or more exceed the corresponding dimensions of the contact surface probes.
8.6 put a layer of contact liquid on the prepared surface of the coating.
8.7 turn on the device, check its performance when displaying video device timebase of the received signals.
8.8 Check on the time scan pulses caused by the presence of an additional measure reflecting boundaries (cracks, scratches, etc.).
9 Order of measurements and rules for their processing
9.1 Measure the surface temperature of the coating in the zones of the selected measurement points.
9.2 In the selected zones are measuring the delay of pulses PVR and record their results.
9.3 9.2 Measurement is repeated 3−5 times.
9.4 For each zone, determine the average delays of the pulses PAVR by the formula
9.5 calculate the coefficient of variation of the measurement results of the delay pulse PWR by the formula
where — standard deviation, calculated according to the formula
9.6 If you are running a ratio of 10
, the calculated values of the delay pulse PVR choose the resulting value
, otherwise the number of dimensions
increase and measure at 9.2 to 9.5 to repeat until the value of the coefficient of variation
reaches a value of 10
.
Note — failure to meet the coefficient of variation of not more than 10
, make the decision on determination of TP with a smaller precision or about the impossibility of measurement.
9.7 Expect given the delays and
according to the formulas
Note — For the most common metals base and coverings and prism Converter, made of Plexiglas, the value can be taken equal to 2.3·10
1/ °C. With higher requirements as to the accuracy of TP value
is determined experimentally.
9.8 TP in each measurement zone is calculated by the formula
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 A.
Annex a (recommended). Form of measurement Protocol
Appendix A
(recommended)
| «CLAIM» | ||
| Head | ||
| name of the organization | ||
| personal signature | initials, surname | |
| «___"___________20___G. | ||
PROTOCOL
determine coating thickness
| (technical object, a controlled phase of a technical object) | |||||||||||||
| 1 measurement date | |||||||||||||
| 2 organization conducting the measurement | |||||||||||||
| 3 the owner of the object | |||||||||||||
| 4 Data about the object: | |||||||||||||
| appointment | |||||||||||||
| the manufacturer and manufacturing methods of the object | |||||||||||||
| the thickness of the base in the area of the point of measurement | |||||||||||||
| the surface condition of the coating | |||||||||||||
| for more information about the object | |||||||||||||
| 5 Sketch of the facility showing the location of areas of measurements and their numbering (listed in the Annex to the Protocol) | |||||||||||||
| 6 Data on materials of the object: | |||||||||||||
| country of origin | |||||||||||||
| material grade (indicating the national or other standard) | |||||||||||||
| manufacturing technology | |||||||||||||
| 7 Effective frequency of the pulse PWR (MHz) | |||||||||||||
| 8 the surface Temperature of coating (°C) | |||||||||||||
| 9 the Highest value of coefficient of variation of the delay pulse PWR | |||||||||||||
Table 1 — Results of measurements in the areas of
| N of the measuring area |
1 | 2 | 3 | … | … |
| The delay pulse PWR, NS | |||||
| Coating thickness, µm |
| Measurements performed by the operator | |
| personal signature | initials, surname |
| Head of laboratory | |
| NDT | |
| personal signature | initials, surname |
Bibliography
| [1] | Viktorov I. A. Sound surface waves in solids. Moscow: Nauka. 1981, 287 p. |
| [2] | Non-destructive testing. Handbook ed. by V. V. Klyuev, vol. 3. M.: Mashinostroenie, 2004. 864 p. |
| [3] | Angles A. L., Erofeev V. I., Smirnov A. N. Monitoring equipment during production and operation. M.: Nauka, 2009. 280 p. |
| [4] | SNiP 11 — M 2−72* Public buildings and facilities. Design standards |
| ________________ * On the territory of the Russian Federation the document is not valid. Deistvuyushim 2.09.03−85. — Note the manufacturer’s database. | |
| [5] | SN 245−71* Sanitary design standards of industrial enterprises |
| ________________ * On the territory of the Russian Federation the document is not valid. Deistvuyushim 2.2.½.1.1.1200−03. — Note the manufacturer’s database. | |
The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: STANDARTINFORM, 2013
