GOST R 55807-2013
GOST R 55807−2013 nondestructive testing. The acoustic method of inspection of the internal pipe cylindrical thread. General requirements
GOST R 55807−2013
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Nondestructive testing
THE ACOUSTIC METHOD OF INSPECTION OF THE INTERNAL PIPE CYLINDRICAL THREAD
General requirements
Non-destructive testing. Ultrasonic monitoring of internal stright pipe threads. General requirements
OKS 77.040.10
Date of introduction 2015−01−01
Preface
1 DEVELOPED by Autonomous non-commercial organization «Scientific-research center of control and diagnostics of technical systems» (ANO «nits KD»), Closed joint stock company «Special design Bureau «Infotrans» (CJSC «Infotrans»)
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 of Russia N 22.11.13 1673-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 national body of the Russian Federation on standardization in the Internet (gost.ru).
Introduction
The most critical technical objects contain a threaded connection, which often determines the structural integrity and safe operation of the facility.
For example in the cost of oil produced by Russian oil companies, 35−40% is spent on the maintenance of pump-compressor pipes and couplings for them. With more than 50% accidents tubular suspension occurs due to faulty screw connections.
Such NDT methods like magnetic particle, eddy current, penetrants, have a fundamental flaw, namely the necessity of disassembly of the connection.
In contrast, the acoustic method does not require disassembly, however, due to the presence of a large number of false signals caused by reflection of the acoustic signal from a thread, single methods of ultrasonic inspection of threaded connections do not currently exist [1].
To monitor the status of internal threads without disassembling the connection criteria for ultrasonic testing is often impossible.
There is, however, a considerable class of objects, reliability in operation which is not determined by the presence of defects like fatigue cracks in the internal thread, and a degree of General degradation due to corrosion, deformation and other processes that violate the geometry of the thread.
For such widespread industrial objects as couplings pipelines, gas cylinders, etc., having internal pipe threads may be used in acoustic monitoring method based on analysis of patterns of spectral distortions of the signal reflected from the surface of the thread [2, 3].
This standard is designed to provide a methodological basis for the application of the acoustic method to determine the state of internal threads on the basis of the analysis of changes in the spectrum of acoustic signals propagating in the material of the threaded connection.
1 Scope
This standard specifies a method for determining the state of the internal parallel pipe thread responsible of technical objects by acoustic method with application of the techniques of spectral processing of acoustic signals.
The standard establishes the basic requirements to the procedure of determining the state of the thread of the acoustic echo method using the electro-acoustic transducers of elastic waves in manual mode scanning the surface of the test object.
The standard is applicable to internal parallel pipe thread according to GOST 6357 with an internal diameter of not less than 30 mm.
Installed standard method can be applied both in laboratory studies and operation of technical objects for various purposes, containing threaded connections with pipe cylindrical thread.
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 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 12.3.002−75 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 6357−81 Basic norms of interchangeability. Pipe thread cylindrical
GOST 11708−82 Basic norms of interchangeability. Thread. Terms and definitions
GOST 17299−78 ethyl Alcohol technical. Specifications
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 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 Terms, definitions, symbols and abbreviations
3.1 this standard uses the terms 11708 according to GOST and GOST 23829.
3.2 this standard applies the designation by GOST 11708, GOST 6357, and the following basic symbols:
| - | the signal | |
| - | the number of points of the waveform for the | |
| - | the number of measurement points in the selected control zone; | |
| - | the signal | |
| - | the amplitude | |
| - | the number of informative harmonic in the amplitude spectrum of the analyzed pulse to | |
| - | the amplitude | |
| - | the outer diameter of the threaded connection mm. |
) waveform for the 
) in the standard sample, bits;
) in a controlled threaded bits;
) of the bottom of the pulse for the 
) of the bottom of the pulse for the 3.3 this standard applies the following abbreviations:
| PC | - | the threaded connection; |
| FFT | - | fast Fourier transform; |
| TOU | - | ultrasonic pulse; |
| SI | - | a measurement means; |
| AT | - | software; |
| SOP | - | a standard sample of the enterprise; |
| EAP | - | — electroacoustic transducer (piezoelectric or electromagnetic-acoustic); |
| PEP | - | the piezoelectric transducer; |
| EMAT | - | electromagnetic-acoustic Converter. |
4 General provisions
4.1 Method based on the use of sensitivity of the shape of the amplitude spectrum of an ultrasonic pulse with a wavelength close to the thread pitch, the shape of her profile, changing in the process of operation.
4.2 About the quality of the carving and its suitability for further use is judged on the basis of comparison of the amplitude spectrum of bottom UI reflected from the thread profile, amplitude spectrum obtained by measurements on the DIS.
Note — figure 1 shows a typical envelope of the amplitude spectrum of bottom signal with a Central spectral frequency of 2.5 MHz, reflected from the thread profile of the SOP.
Figure 1 — Amplitude spectrum for thread SOP
Figure 1 — Amplitude spectrum for thread SOP
Figure 2 shows the envelope of the amplitude spectrum for heavily corroded threads, unusable.
Figure 2 — Amplitude spectrum for heavily corroded thread
Figure 2 — Amplitude spectrum for heavily corroded thread
4.3 the Method is implemented by the manual method of ultrasonic testing with the use of direct combined probes according to GOST 26266 or similar to EMAT.
4.4 Optimal output «microburst» of high frequency (ultrasonic) filling the envelope smooth and effective duration (at the level of 0.6 of the maximum amplitude), equal to 2−4 periods of the fundamental frequency.
4.5 Method provides reliable results when carrying out control in the area outside of the thread end.
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 the control PC, the operator should be guided by GOST 12.1.001, GOST 12.2.003,GOST 12.3.002 and safety regulations in the operation of electrical 12.1.019 according to GOST 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 control PC must be complied with fire safety requirements according to GOST
6 Requirements for measuring instruments
6.1 as SI apply collected from production equipment, or specialized ultrasonic devices that are certified and verified in the prescribed manner.
6.2 the set SI must enter EAP to be installed on the side surface PC and provides the radiation and reception of pulses of longitudinal elastic waves propagating along the diameter PC.
EAP should have the soles of cylindrical shape with a radius of curvature, the value of which is in the range 0,45−0,55 from the outer diameter of the PC.
6.3 SI needs to provide the measurement of the echo method using the UI with a smooth envelope.
6.4 SI should ensure that the discretization of the ultrasonic signal with a frequency that exceeds not less than times the effective frequency used EAP.
6.5 SI must contain an analog-to-digital converters have a precision no less .
6.6 Magnitude and
typically have values of 10 and 12 respectively, but can be refined during preliminary experimental studies.
6.7. should provide the possibility of calculating the amplitude spectra of the bottom pulse using the FFT.
6.7* the Primary acoustic information for each dimension should always be stored on external media, protected from unauthorized access.
__________________
* Numbering corresponds to the original. — Note the manufacturer’s database.
6.8 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 measurement error 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.
6.9 description of the functionality of SI in the operational, engineering and programme documents should reflect the specifications of the hardware and software.
6.10 Operational characteristics of the SI must conform to the requirements of the specifications and of this standard.
6.11 Auxiliary devices and materials
6.11.1 For surface preparation OK using the grinding tool, providing a surface roughness in accordance with 7.2.
6.11.2 For degreasing surfaces used alcohol according to GOST 17299 or acetone churchyard 2768.
6.11.3 When using a probe as a contact is used quite a thick fluid, good ultrasound conducting fluid (e.g., glycerin according to GOST 6259; autoly 6, 10, 18; compressor and other related oil according to GOST 32 having wetting properties with respect to the surface of a PC and the contact surface of the probe).
6.11.4 When the control is used in containers for storing contact liquid, a brush for applying a contact fluid on the surface of PC, rags for wiping of ultrasonic equipment and the operator’s hands, a metal ruler 500 mm for marking the surface of the PC, a marker or chalk to label on the controlled PC, the magazine for business records.
7 Requirements for building control
7.1 PC Material should not have unacceptable delamination, inclusions and other defects detected acoustic echo method.
7.2 Roughness of the side surface PC in control areas — no more than 2.5 microns churchyard 2789.
Note — the Method does not guarantee the required accuracy of assessment of the quality of the PC, if the roughness of the lateral surface exceeds 2.5 µm.
7.3 surface Temperature PC control areas should be in the range from 5 °C to 40 °C.
7.4 Before installing EAP the side surface PC cleaned of dirt, scale, rust and degreased.
8 the Procedure for preparation of the control
8.1 On the basis of technical documentation on the PC define the inner diameter and outer diameter PC
.
8.2 Choose EAP with a nominal frequency equal to 2.5 MHz, and the radius of curvature of the sole, corresponding to 6.2.
8.3 checking the operability of SI spend on the DIS, which does not use a previously used threaded product, the appropriate size and make of material is controlled.
8.4 surface Condition SOP must satisfy the requirements of section 7.
8.5 is Applied (using the contact EAP) contact fluid at the Central area of the surface of DIS.
8.6 Set the EAP include SI and check that it works, displaying the time scan of the reflected pulses.
The duration of the sweep in the ISS must ensure that the following inequality is satisfied:
where is the speed of propagation of elastic longitudinal waves in the material of PC, m/s;
— delay of the probe pulse in microseconds as defined by the technical characteristics of the used SI.
8.7 Check on the time scan pulses caused by the presence in the control area of the additional reflecting boundaries (delaminations, cracks, pores, etc.) in the material SOP, but is not found during radiographic inspection.
9 the Procedure for conducting control and processing rules results
9.1 measurements and processing of results to DIS
9.1.1 For the Central zone of the surface of DIS in the measuring point with number 1 is the waveform containing the bottom UI.
9.1.2 Means of the waveform isolated left and right
border of the reflected UI so that within the selected boundaries of the signal level
exceeded the mean value of the noise at least 6 dB.
9.1.3 using the FFT amplitude spectrum calculated for the array
with the number of values
is an integer, supplementing the number of array values
to the nearest value of the number 2 in the corresponding degree.
Note — Can be used rectangular window function.
9.1.4 Determine the maximum value of the spectrum 
9.1.5 Determine left and right
boundaries of the spectrum, outside of which the value
is less than the value
9.1.6 Means the interval of numbers of harmonics from to
define arrays of local extrema
of the amplitude spectrum
.
9.1.7 calculate the characteristic heterogeneity of the spectrum of DIS according to the formula
where is the number of extrema of the amplitude spectrum on the interval
9.1.8 EAP Moving along the PC in the axial direction with a step of 1 mm, carried out measurements 9.1.1−9.1.7 not less than 10 points.
9.1.9 an Array of values to check for outliers in accordance with GOST R ISO 5725−2.
9.1.10 Determine the average characteristics of the anisotropy spectrum for the DIS according to the formula
9.1.11 calculate the coefficient of variation of measurement results according to the formula
where is the standard deviation calculated according to the formula
9.1.12 Compare the value with the maximum allowable value
obtained during calibration experiments, providing the required accuracy of the control state PC.
If you ratio
the calculated values of the characteristics of the anisotropy spectrum choose the value received . Otherwise, the number of measurement points
increase and measurements 9.1.1−9.1.7 repeat as long as the value of the coefficient of variation reaches a value
.
Note — failure to meet the coefficient of variation of no more than
decide control of the state of the PC with reduced accuracy or the inability of the measurements.
9.2 measurements and processing of results for PC
9.2.1 For the selected zones of control outside of the thread end take measurements and process the results similarly to the measurements of the SOP on 9.1.
9.2.2 as a result of the measurement for each zone of the control PC to determine the average characteristics of the anisotropy spectrum .
9.2.3 On the state of the PC is judged on the basis of comparison of the difference 
obtained during calibration experiments on a PC of the type studied:
— when 
— if you 
10 the Rules of registration of testing results
10.1 the results of the measurements are fixed in the Protocol, the form of which is given in Appendix A.
Additional information to be logged, the order of processing and storage Protocol should be set in the technical documents for the control.
10.2 If the control PC is 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 control Protocol
Appendix A
(recommended)
| «CLAIM" Head | ||||||||||||||||||
| name of the organization | ||||||||||||||||||
| personal signature | initials, surname | |||||||||||||||||
| «___ «_______________ 20 __ G. | ||||||||||||||||||
| PROTOCOL control the state of the PC | ||||||||||||||||||
| (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 | ||||||||||||||||||
| designation PC | ||||||||||||||||||
| PC outer diameter, mm | ||||||||||||||||||
| surface condition | ||||||||||||||||||
| surface temperature, °C | ||||||||||||||||||
| for more information about the object | ||||||||||||||||||
| 5 Sketch of the facility showing the location of zones of control numbering (listed in the Annex to the Protocol) | ||||||||||||||||||
| 6 Data on materials of the object | ||||||||||||||||||
| country of origin | ||||||||||||||||||
| brand materials (with indication of national or other standard) | ||||||||||||||||||
| manufacturing technology | ||||||||||||||||||
| 7 Type of the transducer used | ||||||||||||||||||
| 8 bit ADC used | ||||||||||||||||||
| 9 the sampling frequency of the acoustic signal, MHz | ||||||||||||||||||
Table 1 — Results of measurements in the areas of
| N zone control |
1 | 2 | 3 | … | … |
| The conclusion about the health of the PC |
| Measurements performed by the operator | |
| personal signature | initials, surname |
| Head of laboratory NDT | |
| personal signature | initials, surname |
Bibliography
[1] Nondestructive control. Handbook ed. by V. V. Klyuev, vol. 3. M.: Mashinostroenie, 2004. 864 p.
[2] The Angles A. L., Erofeev V. I., Smirnov A. N. Monitoring equipment during production and operation. M.: Nauka, 2009. 280 p.
[3] Khlybov A. A., Angles, A. L., Spikes, S. N. Quality assessment the internal threads of the cylinders of the spectral-acoustic method // Control. Diagnostika, 2010, No. 5, pp. 40−44
[4] SNiP 11-M 2−72* Public buildings and facilities. Design standards
________________
* Replaced by SNiP II-91−77. SNiP II-91−77 replaced, SNiP 2.09.03−85, SNiP II-89−80. — 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. Act SP
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UDC 620.172.1:620.179.16:006.354 OKS 77.040.10
Key words: echo method, ultrasonic pulse, electro-acoustic transducer, the thread profile, the amplitude spectrum, the digitization of the signal, fast Fourier transform
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The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: STANDARTINFORM, 2014
