A number of standards have been introduced for industrial engineering communications, which require fairly stringent testing of connections. These techniques are being transferred to privately owned systems. The use of methods allows you to avoid emergency situations and carry out external and hidden installations with the required level of quality.

Incoming control

Incoming inspection of pipes is carried out for all types of materials, including metal-plastic, polyethylene and polypropylene after purchasing the products.

The standards mentioned involve testing pipes, regardless of the material from which they are made. Input controlling implies rules for checking the received batch. Inspection of welded joints is carried out as part of the acceptance of communications installation work. The described methods are mandatory for use by construction and installation organizations when commissioning residential, commercial and industrial facilities with water supply and heating systems. Similar methods are used where quality control of pipes in industrial communications operating as part of equipment is necessary.

Sequence of implementation and methods

Acceptance of products after delivery is an important process, subsequently ensuring that there are no wasteful costs for replacing pipe products and no accidents. Both the quantity of products and their features are subject to careful verification. Quantitative verification allows you to take into account the entire consumption of products and avoid unnecessary costs associated with inflated standards and irrational use. The influence of the human factor should not be overlooked.

The work is carried out in accordance with section No. 9 of standard SP 42-101-96.

The sequence of input events is as follows:

Checking the certificate and marking compliance;
Random testing of samples is carried out in case of doubts about quality. The magnitude of the yield strength in tension and elongation during mechanical rupture is studied;
Even if there is no doubt about the supply, a small number of samples are selected for testing, within 0.25-2% of the batch, but not less than 5 pieces. When using products in coils, cut off 2 m;
The surface is inspected;
Inspected for swelling and cracks;
Measure typical dimensions of thicknesses and walls with a micrometer or caliper.

During an official inspection by a commercial or government organization, a protocol is drawn up after the procedure has been carried out.

Non-destructive testing - features

Non-destructive methods are used in functioning utility systems. Particular attention is paid to the actual state of the metal and welded joints. Operational safety is determined by the quality of seam welding. During long-term operation, the degree of structural damage between connections is examined. They can be damaged by rust, which leads to thinning of the walls, and clogging of the cavity can lead to increased pressure and a pipeline rupture.

For these purposes, specialized equipment has been proposed - flaw detectors (for example, ultrasonic), which can be used to carry out work for private and commercial purposes.

In pipeline studies, pipe inspection methods are used:

Using this equipment, the development of cracks or damage to integrity is monitored. Moreover, the main advantage is the identification of hidden defects. It is obvious that each of these methods shows high effectiveness on certain types of damage. The eddy current flaw detector is to some extent universal and cost-effective.

Ultrasonic inspection of pipes is more expensive and demanding, but it is very popular among specialists due to the established stereotype. Many plumbers use the capillary and magnetic particle method, which is applicable to all types of pipe products, including polyethylene and polypropylene. Testex is a popular tool among specialists for checking the tightness of welds.

Conclusion

Of the proposed methods of non-destructive testing, all 4 options are successfully used in practice, but do not have absolute universality. The pipe inspection system includes all types of flaw detectors for carrying out work. The ultrasonic method, as well as the technique based on eddy currents, has a certain degree of versatility. Moreover, the vortex version of the equipment is much cheaper.

Selection by manufacturer

Not selected Computed radiography DUERR NDT / DÜRR NDT AKS Synthesis of NDT Proceq SA SPC Kropus Constanta Center MET Bosello High Technology SaluTron® Messtechnik GmbH ZIO "POLARIS" NPP "Prompribor" ELITES Promtest Bruker TOCHPRIBOR FUTURE-TECH CORP. OXFORD Instruments Amcro Newcom-NDT Sonotron NDT YXLON International Array Corporation Raycraft General Electric Vidar systems corporation Arsenal NK LLC Echo Graphic NPP Mashproekt

Flaw detection of pipes

11.10.2016

Flaw detection of pipes is one of the subcategories of non-destructive ultrasonic testing, along with flaw detection of the base metal and seams. This flaw detection method is one of the most popular services for monitoring oil and gas pipelines in many industries: chemical, oil and gas, fuel, electric power, etc.

During long-term operation, as well as in production, pipelines are exposed to internal and external influences, during which various defects can accumulate (corrosion damage, fatigue cracks, violations of the integrity of the metal, non-metallic inclusions, sunsets, films, cavities, etc.). It is very important to detect such defects in a timely manner before the pipeline fails. Even more important is the ability to perform diagnostics without shutting down or taking the system out of service. That is why non-destructive testing methods are used for flaw detection of pipes, including magnetic (magnetic anisotropy, metal magnetic memory, magnetic permeability), acoustic (pulsed ultrasonic, Lamb waves, phase, acoustic emission), electrical and optical (visual - endoscopic, laser, holographic ).

Such methods are used to identify various defects: leakage, stress control, quality control and condition of welded joints, leakage control and other parameters responsible for the operational reliability of pipelines.

Among the methods for conducting flaw detection of pipelines, one can distinguish thickness measurements of the pipe body and ultrasonic examination of the body and ends of the pipe to identify defects in longitudinal and transverse orientation.

LEADING DOCUMENT

Date of introduction 07/01/91

This guidance document establishes a methodology for manual incoming ultrasonic testing (UT) of the metal quality of cold-deformed, heat-deformed and hot-deformed seamless pipes made of carbon, alloy and austenitic steels used for the manufacture of chemical, oil and gas equipment.

The guidance document applies to pipes with a diameter of 57 mm or more and a wall thickness of 3.5 mm or more.

It is allowed to use mechanized ultrasonic testing of pipe metal according to instructions developed by specialized technological organizations.

The guidance document was developed in accordance with the requirements of the “Rules for the design and safe operation of pressure vessels”, GOST 17410, OST 26-291, technological instructions TI 101-8-68, OST 108.885.01.

1. GENERAL PROVISIONS

1.1. Ultrasonic testing is carried out to identify internal and external defects of pipes such as shells, cracks, sunsets, delaminations, caps and others without deciphering the type, shape and nature of the detected defects, indicating their number, depth and conditional dimensions.

1.2. The need for ultrasonic testing of pipe metal for consumers is established in the following cases:

when supplying pipes that have not been subjected to hydraulic tests and (or) replacement of control tests with physical methods in accordance with the instructions of clause 3.9 of the “Rules for the design and safe operation of pressure vessels” and clause 2.3.9 of OST 26-291;

when using pipes manufactured according to technical requirements without the use of non-destructive testing methods, in order to assess the continuity of metal and sort pipes taking into account the requirements of TU 14-3-460 and other documentation providing for ultrasonic testing, and their subsequent use, for example, for steam pipelines and hot water;

when introducing incoming ultrasonic testing of pipes at the consumer plant by decision of the design or technological department.

1.4. Ultrasonic testing is carried out after eliminating unacceptable defects detected during visual inspection.

1.5. During inspection, detection of defects in the end sections of the pipe at a length equal to half the width (diameter) of the working surface of the converter is not guaranteed.

1.6. Control documentation containing deviations from the requirements of this guidance document or including new control methods must be agreed upon with specialized industry organizations (NIIkhimmash, VNIIPTkhimnefteapparatura, etc.).

2. EQUIPMENT

2.1. Flaw detectors and converters

2.1.1. When inspecting pipe metal, ultrasonic pulse flaw detectors of the types UD2-12, UD-11PU, DUK-66PM or others that meet the requirements of this guidance document must be used. To control pipes for delamination, it is allowed to use ultrasonic thickness gauges such as “Quartz-6” or others.

2.1.2. Thickness gauges and flaw detectors are subject to mandatory state or departmental verification once a year, as well as after each repair. During verification, visual inspection and determination of the technical characteristics of devices must be carried out in accordance with the methodological instructions for verification and the requirements of GOST 23667.

2.1.3. Flaw detectors must be equipped with separate-combined (PC) and inclined transducers with an ultrasonic beam input angle of 38° and 50° at a frequency of 2.5 and 5 MHz, meeting the requirements of GOST 23702.

The dead zone should be no more than:

8 mm - for inclined transducers with an input angle of 38° and 50° at a frequency of 2.5 MHz;

3 mm - for inclined converters with an input angle of 38° and 50° at a frequency of 5 MHz and PC converters at frequencies of 2.5 and 5 MHz.

2.1.4. When using the contact method of ultrasonic testing of pipes with an outer diameter of less than 300 mm, the working surface of the transducer must correspond to the curvature of the surface of the pipe being tested. This is achieved by treating the surface of the transducer (Appendix 1).

Instead of surface treatment, the use of stabilizing supports and attachments is allowed (see Appendix 1).

2.1.5. To measure the thickness of the pipe wall, thickness gauges “Kvarts-6”, UT-93P or others are used, providing similar measurement accuracy, as well as PC converters with a frequency of 2.5; 5 or 10 MHz.

2.2. Standard samples

2.2.1. The set of equipment for checking and adjusting the basic parameters of flaw detectors together with converters should include a set of standard samples CO-1, SO-2 and SO-3 in accordance with GOST 14782, standard samples of the enterprise (according to the terminology of GOST 17410), and adjustment tiles for the thickness gauge.

2.2.2. Standard samples CO-1, CO-2, CO-3 are used to check and determine the main control parameters:

dead zone;

ultrasonic beam exit points;

converter booms;

the angle of inclination of the acoustic axis of the transducer;

angle of entry of the ultrasonic beam.

2.2.3. Standard samples of the enterprise are used to adjust the depth-measuring device and the sensitivity of the flaw detector. As a standard sample, the enterprise uses a section of a defect-free pipe (Fig. 1), made of the same material, the same standard size and having the same surface quality as the controlled pipe. The deviation of the dimensions of standard samples of the enterprise (diameter, thickness) from the dimensions of the controlled pipe by no more than ±10% is allowed. On the outer and inner surfaces of the sample, control defects (artificial reflectors) such as rectangular marks are applied according to GOST 17410.

2.2.4. Standard samples of the enterprise for adjusting the thickness gauge and sensitivity of a flaw detector with a PC converter are made in steps from the corresponding section of pipe (Fig. 2). A flat-bottomed hole of a given size is made in the sample.

2.2.5. Standard samples of the enterprise are divided into control and working.

The equipment is set up using working samples, and working samples are checked using control samples at least once a quarter. If the difference in signal amplitudes from the marks and the flat-bottomed hole in the working and control samples exceeds ±2 dB, the working sample is replaced with a new one.

Plant Standard for Slope Transducers

Mark the steel grade, diameter (2 R), wall thickness S, groove depth h

Enterprise Standard Sample for PC Converters

Mark steel grade, diameter D, step thickness (measured value)

3. PREPARATION FOR CONTROL

3.1. General provisions

3.1.1. When carrying out control, the ambient air temperature in the control zone should be in the range from 5 to 40 °C, the pipe wall - no more than 50 °C.

3.1.2. When carrying out testing in an open place during the day or under strong artificial lighting, it is necessary to take measures to darken the flaw detector indicator screen.

3.1.3. During inspection, stripping and other mechanical work that complicates inspection should not be carried out on inspected pipes.

Convenient access to the controlled pipe must be provided.

3.2. Requirements for flaw detectors

3.2.1. To carry out incoming ultrasonic testing of pipe metal in accordance with GOST 20415, flaw detectors who have undergone theoretical and practical training according to the approved program, have received a certificate for the right to carry out ultrasonic testing, and have a qualification of at least 3rd category that meets the requirements of the “Unified Tariff and Qualification Directory of Works and Professions” must be allowed workers."

Assessment of the quality of pipe metal based on the results of ultrasonic testing must be carried out by flaw detectors of at least the 4th category.

3.2.2. Ultrasonic inspection of pipe metal should be carried out, as a rule, by a team of two flaw detectors, who alternately replace each other when performing inspection operations. With a supply voltage of up to 36 V, it is allowed to perform inspection by one flaw detector.

3.2.3. Ultrasonic inspection flaw detectors must undergo recertification, theoretical and practical, at the place of work at least once a year. If there is a break in work for more than 6 months, flaw detectors are deprived of the right to carry out inspections until they pass repeated tests, and for more than 1 year - until they undergo a repeated training course and recertification.

3.2.4. The work of flaw detectors during recertification is checked on at least three sections of pipes with defects and is documented in a protocol.

The verification commission should include:

Head of the Department of Non-Destructive Testing Methods (CDT, QT);

Head of the Laboratory of Non-Destructive Testing Methods;

ultrasonic flaw detection engineer;

safety engineer; training engineer.

A corresponding entry is made in the flaw detectorist’s certificate (insert) about passing the qualification test.

3.2.5. The work of each flaw detector is checked at least once a week by repeated selective ultrasonic inspection of at least 5% of the total number of pipes, but not less than one, checked by him per shift. The work can be checked by a shift senior flaw detector, an engineer or a more highly qualified flaw detector. If missed defects are detected, the pipes are re-inspected to the same extent by another flaw detector.

If missed defects are repeatedly detected within one month by the same flaw detector, a decision must be made to deprive him of the right to control using the ultrasonic method until an extraordinary certification is carried out no earlier than a month after additional training and industrial internship.

3.3. Requirements for the control area

3.3.1. Ultrasonic testing should be carried out in the workshop in a specially designated area or area where the pipes being monitored are located.

3.3.2. The ultrasonic testing area should have:

power supply voltage 220 (127) and 36 V with a frequency of 50 Hz;

equipment grounding buses;

stand or carts for flaw detectors;

racks for pipes.

3.3.3. In workshops producing chemical and petrochemical equipment, special ultrasonic testing laboratory rooms with an area of at least 4.5 m2 must be organized for storing flaw detection equipment, standard samples, equipment, tools and auxiliary materials, as well as for carrying out preparatory, adjustment and repair work. - for each employee in accordance with the requirements of SN 245-71.

3.3.4. In the laboratory room of the ultrasonic testing facility there should be:

ultrasonic flaw detectors with sets of standard transducers, standard and test samples;

AC supply with a frequency of 50 Hz and voltage of 220 (127) and 36 V;

chargers type AZU-0.4 or others;

voltage stabilizer when network voltage fluctuations exceed plus 5 or minus 10% of the nominal value;

reel with portable network cable;

ground bus;

a set of plumbing and measuring tools;

contact medium and cleaning material;

work tables;

racks and cabinets for storing equipment and materials.

3.4. Surface preparation under control

3.4.1. Pipes must be cleaned of dust, abrasive powder, dirt, oils, paint, flaking scale and other surface contaminants and numbered. Sharp edges at the end of the pipe should not have burrs.

3.4.2. There should be no dents, nicks, cutting marks, leaks, splashes of molten metal or other surface irregularities on the outer surfaces of the pipes.

If mechanical processing is used, the surface must have a roughness Rz? 40 - according to GOST 2789.

3.4.3. The quality control of surface preparation must be checked by technical control service workers. It is recommended to make surface cleaning samples.

The pipes are presented to the flaw detector fully prepared for inspection.

3.4.4. To ensure acoustic contact between the surfaces of the transducer and the product, it is recommended to use the contact media specified in reference Appendix 2. It is also possible to use technical petroleum jelly, machine oil, technical glycerin with their subsequent removal from the surface of the pipes.

At elevated temperatures or large curvature of the surface of the controlled pipes, a contact medium of a thicker consistency should be used. At low temperatures, it is recommended to use autolu or transformer oil.

3.5. Selecting control parameters and setting up the flaw detector

3.5.1. The choice of control parameters depends on the outer diameter of the pipe and the wall thickness. Ultrasonic testing parameters are:

converter exit point and boom;

ultrasonic beam entry angle;

operating frequency;

extreme sensitivity;

way of sounding;

speed, scanning step.

The main parameters of ultrasonic testing of pipe metal are given in the table.

3.5.2. The exit point of the ultrasonic beam and the transducer boom are determined using the standard CO-3 sample - according to GOST 14782.

3.5.3. The angle of insertion of the ultrasonic beam is measured using the scale of the standard sample SO-2-according to GOST 14782. For transducers with an acoustic axis tilt angle of 30° and 40°, the insertion angle should be 38 ± 2° and 50 ± 2°, respectively.

3.5.4. To ensure acoustic contact of transducers with a curved working surface (clause 2.1.4) with the flat surface of standard samples CO-2 and CO-3, a thicker contact medium or a removable local bath with a wall height of 2 - 3 mm should be used.

3.5.5. Setting up a flaw detector with a converter includes setting the operating frequency, setting the depth gauge, setting the control zone, maximum sensitivity, and checking the dead zone.

3.5.6. The operating frequency is set by turning on the corresponding buttons on the top panel (flaw detectors UD-11PU, UD2-12, etc.), by connecting circuits corresponding to the given frequency and converter (flaw detectors DUK-66PM, DUK-66P) or by other methods in accordance with the instructions for operating the device.

Ultrasonic testing parameters

Pipe diameter, mm	Wall thickness, mm	Entry angle	Frequency, MHz	Sounding method

				Direct and once reflected beam
St. 75 to 100				Single and double reflected beam
St. 75 to 100				Direct and single-reflected beam (for thicknesses up to 8 mm, testing with a single and double-reflected beam is allowed)
St. 100 to 125

	St. 12 to 18
St. 125 to 150

	St. 14 to 24
St. 150 to 175

	St. 16 to 32
St. 175 to 200

	St. 20 to 36
St. 200 to 250
St. 250 to 300
St. 300 to 400
St. 400 to 500

Setting the control zone for tilt transducers

a - for longitudinal risks; b - according to ring risks; c - oscillograms

When using foreign flaw detectors, thickness gauges and converters, instead of the operating frequency of 2.5 and 5 MHz, it is allowed to use frequencies of 2 and 4 MHz, respectively.

3.5.7. The flaw detector depth-measuring device for the inclined transducer is adjusted according to the standard enterprise sample (see Figure 1) with rectangular marks made on the outer and inner surfaces of the sample. The beginning of the scale is adjusted according to the coordinates of the marks ( S, L 1), when it is sounded with a direct beam (Fig. 3), the end of the scale is adjusted according to the coordinates (2 S, L 2), marks on the outer surface when sounded by a once reflected beam. The end of the scale can be adjusted according to the mark on the inner surface when sounded by a doubly reflected beam (coordinates 3 S, L 3).

Setting up a depth measuring device by coordinates S, L(respectively Y, X in a flaw detector) is carried out separately for longitudinal and annular marks on the sample.

3.5.8. Adjustment of the depth gauge of the flaw detector and the thickness gauge when sounding with a PC transducer is carried out according to the standard stepwise enterprise model (see Figure 2) with known wall thicknesses. The beginning of the scale is adjusted by coordinate S o equal to the smaller wall thickness; the end of the scale is adjusted according to the coordinate S, equal to the greater wall thickness. It is recommended to install the PC transducer in such a way that the acoustic axes of both piezoplates are located in the axial plane of the pipe. The setup procedure is described in the operating instructions for the devices.

3.5.9. The control zone for inclined transducers is set using echo signals from the marks. When sounding a direct and once reflected beam, the leading edge of the strobe pulse is set to the right of the probing signal, and the trailing edge is combined with the leading edge of the echo signal 2 from the mark on the outer surface (see Fig. 3).

In the case of sounding the pipe wall with a once and twice reflected beam, the leading edge of the strobe pulse is combined with echo signal 1 from the mark on the inner surface, and the trailing edge is combined with echo signal 3 from the same mark, received by the double reflected beam.

3.5.10. For a PC converter, the control zone should be set between the probing signal and the bottom echo signal 2 (Fig. 4). Echo 3 from the flat bottom hole will be located in the middle of the control zone (0.5 S).

It is allowed to install a control zone between adjacent bottom signals in case of multiple reflections from the pipe wall, for example, zone 2 S - 3S(see drawing 4c).

3.5.11. The maximum sensitivity of a flaw detector with a converter should be adjusted according to rectangular marks in a standard enterprise sample (see Figure 1). The depth of the notches should be set as a percentage of the pipe wall thickness from the next row - according to GOST 17410: 3, 5, 7, 10, 15%. The specific depth value must be established by the technical specifications for the pipes. In the absence of technical requirements, it is recommended to use standards for assessing the continuity of the pipe wall in accordance with Appendix 3.

Echo signals from control marks in the sample must be installed on the flaw detector screen with a height of at least 30 mm.

3.5.12. The sensitivity is adjusted so that the amplitude of the echo signals from the internal and external marks located in the control zone differs by no more than 3 dB. If this difference cannot be compensated for by an electronic device or method, then pipe inspection is carried out by adjusting the sensitivity separately for the direct and reflected beam.

3.5.13. The maximum sensitivity of the control to detect delaminations is adjusted using a flat-bottomed hole located at a depth of 0.5 S in a standard example of an enterprise (see Figure 1). The diameter is determined from the following series - according to GOST 17410: 1.1; 1.6; 2.0; 2.5; 3.0; 3.6; 4.4; 5.1; 6.2 mm (equivalent areas of 1; 2; 3; 5; 7; 10; 15; 20; 30 mm, respectively). The specific diameter value must be established by the technical specifications for pipes, the requirements of drawings and other documentation. In the absence of technical requirements, it is recommended to apply standards for assessing continuity in accordance with Appendix 3.

Setting the control zone for the PC converter

a - sound diagram; b, c - signal oscillograms

Scheme for checking pipes for delamination

a - diagram of the transducer movement; b - signal oscillogram

The amplitude of the echo signal from the flat-bottomed hole must be set on the flaw detector screen with a height of at least 30 mm, while taking into account the accepted position of the control zone on the flaw detector screen in accordance with clause 3.5.10.

3.5.14. When searching for defects, set the search sensitivity with the ATTENUATION knobs (buttons) 6 dB less (in value).

3.5.15. The correct setting of the maximum sensitivity of the flaw detector with a converter should be checked every time the equipment is turned on, as well as after every hour of operation.

Check the characteristics of the converter using standard samples CO-2, CO-3 at least twice a shift as the converter wears out.

3.5.16. After setting the maximum sensitivity, the dead zone should be checked by identifying holes with a diameter of 2 mm in a standard CO-2 sample, located at depths of 3 and 8 mm in accordance with the requirements of paragraph 2.1.3. If the specified holes are not detected, it is necessary to repeat the maximum sensitivity setting in accordance with paragraphs. 3.5.11 - 3.5.13 or replace the converter.

3.5.17. The scanning speed of the pipe surface with the transducer should be no more than 100 mm/s, the scanning step (between adjacent trajectories) should be no more than half the size of the piezoelectric plate in the transducer used.

It is allowed to use other scanning modes if they are specified in the technical requirements for pipes.

4. ULTRASONIC CONTROL

4.1. General provisions

4.1.1. When ultrasonic testing of pipes, the following sounding directions should be used:

1) chordal, perpendicular to the generatrix of the cylinder, - to identify longitudinally oriented defects: scratches, burrs, cracks, etc.;

2) along the generatrix - to identify transversely oriented defects: cracks, cavities, etc.;

3) radial, along the radius, - to identify delaminations, sunsets, and also to measure wall thickness.

4.1.2. The continuity of pipe walls is monitored using the pulse-echo method using a combined transducer switching circuit in the contact version. During the testing process, the transverse-longitudinal movement of the transducer is performed at a speed of no more than 100 mm/s with a step between adjacent trajectory lines of no more than half the size of the piezoelectric element.

4.1.3. An example of determining the complexity of pipe inspection is given in Appendix 4.

4.2. Methodology for monitoring longitudinal defects

4.2.1. To identify longitudinally oriented defects, chordal sounding should be used with an inclined transducer when moving it perpendicular to the generatrix of the cylinder along the entire outer surface of the pipe in one direction, and at the ends of the pipes - at a length equal to twice the wall thickness, but not less than 50 mm, in two opposite directions.

Control parameters are selected according to the table.

Sounding is performed by a direct and once reflected beam. If there are interfering signals in the control area with a direct beam, it is allowed to sound once and twice with a reflected beam.

4.2.2. The maximum sensitivity is adjusted according to longitudinal marks with depth h in the standard model of the enterprise (see Figure 1) in accordance with the requirements of paragraphs. 3.5.11 - 3.5.12.

4.2.3. The diagram of the transducer's movements along the surface of the pipe is shown in Fig. 6a. It is recommended to move the transducer along an arc in sectors 100 - 150 mm long, depending on the diameter of the pipe, followed by rotating the pipe to the appropriate angle to control the next sector.

4.3. Methodology for monitoring transverse defects

4.3.1. To identify transversely oriented defects, sounding should be used along the generatrices of the cylinder along the outer surface of the pipe in one direction, and at the ends of the pipes - at a length equal to twice the wall thickness, but not less than 50 mm, in two opposite directions. Control parameters are selected according to the table. Sounding is performed with a direct and once reflected beam, and in the presence of interfering signals in the control zone - with a direct beam, once and twice reflected.

Pipe wall inspection schemes

a - for longitudinal defects; b - for transverse defects

4.3.2. The maximum sensitivity is adjusted according to transverse grooves with depth h in the standard model of the enterprise (see Figure 1) in accordance with the requirements of paragraphs. 3.5.11 - 3.5.12.

4.3.3. The diagram of the transducer's movements along the surface of the pipe is shown in Fig. 6b.

4.4. Delamination control technique

4.4.1. The end sections of pipes subject to welding with a wall thickness of at least 10 mm over a length equal to twice the wall thickness, but not less than 50 mm, are subject to control in order to identify delaminations and sunsets. Sounding is performed in the radial direction by a PC transducer at a frequency of 2.5 or 5.0 MHz, and the transducer is installed in such a way that the acoustic axes of both piezoplates are located in the axial plane of the pipe.

4.4.2. The maximum sensitivity is adjusted using a flat-bottomed hole with a diameter of d in the standard model of the enterprise (see Figure 2) in accordance with the requirements of clause 3.5.13.

4.4.3. The diagram of the transducer's movements along the surface of the pipe is shown in Fig. 5. In the absence of delamination, only bottom signal 1 from the inner surface of the pipe is observed on the flaw detector screen. If there is delamination, signal 2 from the defect appears before the bottom signal, while the bottom signal decreases or completely disappears.

4.4.4. The dimensions and configuration of the delaminations are determined by the conventional boundary. The conventional boundary is taken to be the line corresponding to the position of the center of the transducer above the defect, at which the signal amplitude decreases to a level of 15 mm, corresponding to 0.5 amplitude from the flat-bottomed hole.

By outlining a conventional boundary on the surface of the pipe, the dimensions of the delamination and its nominal area are determined.

4.5. Defect registration

4.5.1. When an echo signal appears in the control zone, the following characteristics are measured:

reflector location coordinates;

reflected signal amplitude;

conditional length of the defect along or across the pipe axis.

The location of unacceptable defects is marked on the surface of the pipe, indicating the depth.

The specified characteristics are determined using a flaw detector configured in accordance with paragraphs. 3.5.11 - 3.5.13.

4.5.2. The reflector coordinates “Du” and “Dx” are determined using the flaw detector’s depth-measuring device in accordance with the flaw detector’s operating instructions using a scale on the screen (DUK-66PM) or on a digital indicator (UD2-12).

4.5.3. The signal amplitude is measured by the height of the pulse on the screen in mm or the amount of signal attenuation in dB to a level of 30 mm.

4.5.4. The conditional length of the reflector is measured by the length of the zone of movement of the transducer along the pipe axis when detecting longitudinal defects or along a circular arc when detecting transverse defects, within which the echo signal changes from the maximum value to the level of 15 mm, corresponding to half the amplitude of the signal from the mark (see paragraph. 3.5.11).

4.5.5. Defects whose signal amplitudes exceed the level of 15 mm on the flaw detector screen are subject to registration, i.e. level 0.5 amplitude from a given control reflector: marks, flat-bottomed hole.

4.5.6. Echoes from defects must be distinguished from interfering signals.

The reasons for the appearance of interfering (false) signals may be:

unevenness of the pipe surface, causing the converter to swing and the appearance of an air gap under the converter;

excess contact medium;

marks and protrusions on the end surfaces of the pipe;

dihedral angle of the prism (with a small boom of the transducer);

PC converter delay line.

Interfering signals caused by disruption of acoustic contact or reflections from the corners and boundaries of the delay line of the transducer are distinguished by the fact that when the transducer moves, they do not move along the scan line on the flaw detector screen.

Sources of signals moving along the scan line are determined by measuring the coordinates Dx, Du of reflectors and their analysis.

A - point permissible defect, the amplitude of the signal from which does not exceed the amplitude from the control reflector (marks, flat-bottomed hole);

D - point unacceptable defect, the signal amplitude from which exceeds the amplitude from the control reflector;

BD - an extended (regardless of length) unacceptable defect, the signal amplitude from which exceeds the amplitude level (30 mm) from the control reflector or an extended unacceptable defect, the signal amplitude from which exceeds the level of 0.5 amplitude (15 mm) from the control reflector, and the extent exceeds the permissible value for longitudinal and transverse defects (Appendix 3);

BA - an extended permissible defect, the signal amplitude from which exceeds the level of 0.5 amplitude (15 mm) from the control reflector, and the conditional extent does not exceed the permissible value for longitudinal and transverse defects; or an extended (regardless of length) defect, the signal amplitude from which does not exceed the level of 0.5 amplitude from the control reflector;

P - delamination or other defect (sunset, non-metallic inclusion), the amplitude of the signal from which exceeds the amplitude from the control reflector (flat-bottomed hole);

RA - delamination or other permissible defect, the amplitude of the signal from which does not exceed the amplitude from the control reflector (when monitoring the RS with a converter).

4.5.8. After the letter designation of the defect, the following should be indicated:

the depth of the defect from the surface;

conditional length (for defects of type BD, BA);

conditional (equivalent) area (for defects of type P, RA).

4.6. Method for controlling wall thickness

4.6.1. Pipe wall thickness control is carried out using ultrasonic thickness gauges (clause 2.1.5) and PC converters. It is allowed in some cases (insufficient sensitivity of the thickness gauge, the presence of stitching in the metal, causing false measurements, etc.) to use ultrasonic flaw detectors of the UD2-12 type with a digital indication of the measurement results to measure thickness.

The choice of converter type and operating frequency depends on the wall thickness and steel grade of the pipe, curvature and roughness of the contact surface. The procedure for selecting a specific transducer is specified in the thickness gauge operating manual.

4.6.2. Wall thickness measurements are carried out on sections of the pipe specified in the technical requirements (see Appendix 3).

4.6.3. When measuring PC thickness, the transducer must be installed on the surface of the pipe (clause 3.5.8); As a rule, the acoustic axes of both piezoplates should be in the axial plane of the pipe.

5. EVALUATION OF ULTRASONIC CONTROL RESULTS

5.1. Based on the results of measuring the pipe wall thickness, a conclusion is given on compliance with the requirements specified in the technical specifications for pipes or other technical documentation.

5.2. Assessment of pipe metal continuity based on ultrasonic inspection results is carried out in accordance with the requirements established in the standards or technical specifications for pipes.

5.3. In the absence of technical requirements for assessing the quality of pipes in standards, specifications, drawings, it is recommended to apply regulatory requirements in accordance with Appendix 3.

6. IRRIGATION CONTROL RESULTS

6.1. The results of ultrasonic testing of pipes must be recorded in the log book, in the conclusion, and, if necessary, in the control card.

6.2. The log should indicate:

Order number;

number of the controlled pipe;

pipe dimensions and material;

standard, specifications for pipes;

technical documentation on ultrasonic testing;

depth of mark for setting sensitivity (see Appendix 3);

area of the flat-bottomed hole in the sample (see Appendix 3);

type of ultrasonic flaw detector and thickness gauge;

transducer type and input angle;

operating frequency of ultrasonic vibrations.

An example of filling out a log and drawing up a control card is given in Appendix 5.

6.3. The recommended form of conclusion based on the results of ultrasonic testing is given in Appendix 6. If necessary, it is allowed to give a conclusion for a batch of pipes of the same standard size, the same grade of steel (with a list of rejected pipes attached and an abbreviated record of defects in accordance with paragraphs 4.5.7, 4.5.8).

7. SAFETY INSTRUCTIONS FOR ULTRASONIC CONTROL

7.1. When carrying out work on ultrasonic testing, the flaw detector must be guided by the “Rules for the technical operation of consumer electrical installations” and “Safety rules for the operation of consumer electrical installations”, approved by the USSR State Energy Supervision Authority on December 21, 1984, as well as GOST 12.2.007.0 “Electrical products. General safety requirements" and GOST 12.2.007.14 "Cables and cable fittings. Safety requirements".

7.2. Persons at least 18 years of age who have undergone training on safety rules (with an entry in the journal) and who have a certificate of testing knowledge of the above rules (clause 7.1), as well as the production instructions of the enterprise and this guidance document are allowed to work on ultrasonic testing.

7.3. Safety training is carried out in accordance with the procedure established at the enterprise.

7.4. Fire safety measures are carried out in accordance with the requirements of the “Standard Fire Safety Rules for Industrial Enterprises”, approved by the GUPO of the USSR Ministry of Internal Affairs in 1975 and GOST 12.1.004 “Fire Safety. General requirements".

7.5. Before turning on the flaw detector, the flaw detector must ensure that there is reliable grounding. Grounding of the flaw detector in the workshop must be carried out in accordance with the requirements of GOST 12.1.030 “SSBT. Electrical safety. Protective grounding, grounding.”

Grounding of ultrasonic flaw detectors is carried out by a special conductor of a portable wire, which should not simultaneously serve as a conductor of operating current. As a grounding conductor, you should use a separate core in a common sheath with the phase wire, which should have the same cross-section as it.

It is prohibited to use the neutral wire for grounding. The conductors of wires and cables for grounding must be copper, flexible, with a cross-section of at least 2.5 mm.

7.6. Plug sockets for portable electrical appliances must be equipped with special contacts for connecting a grounding conductor. In this case, the design of the plug connection must exclude the possibility of using current-carrying contacts as grounding contacts. The connection of the grounding contacts of the plug and socket must be made before the current-carrying contacts come into contact; the shutdown order should be reversed.

7.7. The flaw detector is connected to the power supply and disconnected by the electrician on duty. At specially equipped posts, a flaw detector can connect the flaw detector.

7.8. It is strictly prohibited for flaw detectors to work under lifting mechanisms, on unstable shaky structures and in places where damage to the power supply wiring of flaw detectors is possible.

7.9. When using lifting mechanisms in the control area, the requirements of the “Rules for the Design and Safe Operation of Load-Lifting Cranes” approved by the USSR State Mining and Technical Supervision Authority in 1969 must be taken into account.

7.12. In noisy workshops it is necessary to use personal noise protection equipment - noise suppressors - in accordance with GOST 12.4.051.

7.13. If possible, the workplaces of flaw detectors should be fixed. If welding or other work involving bright lighting is carried out at a distance of less than 10 m from the inspection site, it is necessary to install shields.

7.14. Accessories used by the flaw detector: oilers, cleaning cloths and paper - must be stored in metal boxes.

7.15. When performing ultrasonic testing, you should be guided by “Sanitary norms and rules when working with equipment that creates ultrasound transmitted by contact to the hands of workers,” No. 2282-80, approved by the Chief State Sanitary Doctor of the RSFSR on December 29, 1980.

7.16. According to the requirements of sanitary norms and rules No. 2282-80 and order No. 700 of June 19, 1984 of the USSR Ministry of Health, flaw detectors entering work must undergo a mandatory medical examination. Hired personnel must undergo periodic (once a year) medical examination.

7.17. After major and preventative repairs, flaw detectors with transducers must be checked for permissible ultrasonic field levels - in accordance with GOST 12.1.001. In this case, the parameters of the ultrasonic field acting on the hands of the flaw detector should not exceed the values given in sanitary norms and rules No. 2282-80. The results of measurements of ultrasonic field parameters must be documented in a protocol in Form 334, approved by order of the USSR Ministry of Health dated October 4, 1980 No. 1030.

7.18. The ultrasonic testing area must also meet the requirements of sanitary standards and regulations No. 2282-80, as well as GOST 12.1.005 and GOST 12.1.007.

7.19. To protect hands from exposure to contact media and ultrasound during contact transmission, flaw detectors must work in mittens or gloves that do not allow contact media to pass through.

In this case, it is necessary to use two pairs of gloves: outer - rubber and inner - cotton or two-layer according to GOST 20010.

7.20. In the cold and transitional periods of the year, flaw detectors must be provided with warm overalls according to the standards established for a given climatic zone or production.

METHODS OF MATING CONVERTER AND PIPE SURFACES

1. Transducer surface treatment

In order to ensure reliable contact, the working surface of the transducer is processed to match the corresponding surface of the controlled pipe. It is recommended to have a set of transducers that covers the range of pipe diameters with an interval of ±10% (for example, with transducer surface radii of 31, 38, 46 mm, the range of controlled pipes from 57 to 100 mm).

To mark the body (prism) of the transducer, it is advisable to make transparent templates (from plexiglass) with marks (Fig. 1a) corresponding to the angles of inclination of the acoustic axis of the transducer (30° and 40°). On the transducer prism, a line is drawn through the input point corresponding to the angle a of the acoustic axis (see Fig. 1b). The template is applied to the transducer body, and the acoustic axis of the transducer must coincide with the corresponding line on the template (see Fig. 1c). Then an arc with a radius is marked on the transducer R. Initially, the prism is processed with a file or on an emery wheel, and then the surface is finished using sandpaper, which is placed on a piece of pipe. The accuracy of finishing is checked using a template.

As the converter wears out, repeat the above operations.

2. Application of stabilizing supports

When testing along a cylindrical surface, the use of stabilizing supports (Fig. 2) mounted on the transducer is allowed. The dimensions of the supports depend on the types and sizes of the converters used.

Scheme for marking and finishing the surface of the converter

a - template; b - body (prism); c - marking diagram; g - finishing

Support for tilt transducers

Approximate dimensions, mm:

A? H; IN =b + 2; WITH = 8 ? 12; S = 2 ? 3; r = 5 ? 7

n= 4 ? 15 (depending on the type of converter);

a - sketch of the support;

b - support installation diagram

Support reach (size h) relative to the surface of the transducer is calculated using the formula:

Where R- outer radius of the pipe;

r- radius of support;

n- converter boom;

s- thickness of the support wall.

Calculation example.

When inspecting a pipe with a diameter of 60 mm and dimensions r= 6 mm, n= 12 mm, s= 2 mm, offset h= 1 mm.

It is allowed to use supports of other designs that ensure the required position of the transducer, for example, nozzles made of wear-resistant material (fluoroplastic, caprolon, etc.)

APPENDIX 2

Information

types of contact media

1. Contact medium of the Chernivtsi Machine-Building Plant named after. Dzerzhinsky (author's certificate No. 188116).

1.1. The contact medium is an aqueous solution of polyacrylamide and sodium nitrite in the following ratio (%):

1.2. Cooking method

In a vessel with a volume of about 10 liters, equipped with a stirrer with an angular speed of 800 - 900 rpm, load 4 liters of water and 1.5 kg of 8% technical polyacrylamide and mix for 10 - 15 minutes until a homogeneous solution is obtained.

Then add 600 ml of 100% sodium nitrite solution.

2. Contact medium based on carboxymethylcellulose (author's certificate No. 868573).

2.1. The contact medium is an aqueous solution of CMC, synthetic soap and glycerin - according to GOST 6259 in the following ratio (%):

The industry produces carboxymethylcellulose grades 85/250, 85/350 and others - according to MRTU 6-05-1098 in fine-grained, fibrous and powdery states.

2.2. The contact medium is prepared by stirring carboxymethylcellulose in water for 5 - 10 minutes, then the solution is kept for 5 - 6 hours until the CMC is completely dissolved.

Note. The consumption of any type of contact medium is approximately 0.3 kg per 1 m 2 of pipe.

REGULATORY REQUIREMENTS FOR PIPES FOR ULTRASONIC CONTROL AND ASSESSMENT OF METAL CONTINUITY

The specified regulatory requirements may be used for ultrasonic inspection of pipes in the absence of technical requirements in standards, technical specifications or other regulatory and technical documentation.

The object of control is pipes made of carbon and alloy steel grades St3, 20, 15GS, 15XM, 12Х11В2МФ, etc.

Technical requirements

1. Scope of control

1.1. Inspection of longitudinal and transverse defects is carried out in one direction with inclined transducers, transverse waves, in a volume of 100% at the ends of pipes over a length equal to twice the thickness, but not less than 50 mm, in two opposite directions.

Control of delaminations at the ends of pipes at a length equal to twice the thickness, but not less than 50 mm, is carried out with PC converters (longitudinal waves).

1.2. Wall thickness control is carried out at the ends of the pipes and in the middle part at four points along the perimeter of the pipe in 90° increments.

2. Control sensitivity

2.1. Sensitivity when testing with transverse waves is adjusted according to rectangular marks - according to GOST 17410, with a depth of 10% of the nominal pipe wall thickness, but not more than 2 mm, a width of 1.5 mm, a length of 100 mm.

2.2. Sensitivity when testing with longitudinal waves is adjusted using a flat-bottomed reflector - according to GOST 17410:

with a diameter of 3.0 mm (area 7 mm 2) - for pipe wall thickness up to 10 mm;

with a diameter of 3.6 mm (area 10 mm 2) - for pipe wall thickness over 10 mm to 30 mm;

with a diameter of 5.1 mm (area 20 mm 2) - for pipe wall thickness over 30 mm.

3. Evaluation of control results

3.1. Inadmissible defects include:

point and extended defects, the signal amplitude from which exceeds the control level (30 mm);

extended longitudinal defects with a reflected signal amplitude of more than 0.5 amplitude from the control mark, the nominal length of which is more than 100 mm for pipes with a diameter of over 140 mm and more than 65 mm for pipes with a diameter of 57 to 140 mm;

extended transverse defects with a reflected signal amplitude of more than 0.5 amplitude from the control mark, the conditional length of which along the arc of the outer surface is more than 50 mm.

Note. The assessment of the depth of scratches and the conditional length of longitudinal and transverse defects is given on the basis of the standards of the “Technological instructions for ultrasonic quality control of pipe metal” VNIIPTkhimnefteapparatura, Volgograd, 1980, agreed with TsNIITmash, Moscow, 1980, and VNITI, Dnepropetrovsk, 1980 ., intended for the evaluation of pipes manufactured in accordance with GOST 8731 and used for the manufacture of steam and hot water pipelines piping the PPR-600 furnace instead of pipes with technical requirements in accordance with TU 14-3-460.

3.2. Inadmissible delaminations include defects whose signal amplitude exceeds the signal amplitude (30 mm) from a flat-bottomed reflector.

3.3. Maximum deviations in pipe wall thickness should not exceed:

15%, -10% - for pipes with a diameter of up to 108 mm;

20%, -5% - for pipes with a diameter of more than 108 mm.

Note. Deviations in thickness are indicated in accordance with the requirements of TU 14-3-460.

APPENDIX 4

DETERMINING THE LABOR-INTENSITY OF CONTROL

The complexity of ultrasonic pipe inspection includes time spent on monitoring longitudinal and transverse defects, delaminations at the ends of pipes and measuring wall thickness.

The estimated time to move the transducer depends on the speed and scanning step and is determined by the formula:

Where D- outer diameter of the pipe, mm;

L- pipe length, mm;

l o - length of the pipe section to be tested for delamination, mm;

v- scanning speed, mm/s;

t- scanning step, mm.

Taking into account the implementation of auxiliary operations (setting up a flaw detector, measuring and marking defects, recording inspection results, etc.), additional time is required (up to 20 - 30% of the calculated one). Thus, the total time for pipe inspection is:

T = (1,2 ? 1,3)T o.

For example, to control a pipe with a diameter of 108 mm, a wall thickness of 10 mm and a length of 3 m (with l o = 50 mm, v= 80 mm/s, t= 6 mm) estimated time T o = 69 min, total labor intensity T= 83 - 90 min.

Measuring wall thickness requires approximately 1 minute for each point (measuring four points in three sections - 12 minutes).

APPENDIX 5

Journal of Ultrasonic Pipe Inspection

Order no.

Standard, TU

steel grade

Pipe length, mm

Pipe diameter, mm

Wall thickness, mm

NTD according to ultrasonic testing

Type of flaw detector, thickness gauge

Converter type, input angle

Frequency, MHz

Depth of marks, mm

Ultrasound testing results

Delamination, mm 2

Last name of flaw detector

Conclusion

Measured thickness, mm

Point defects

Extended defects

Transverse

GOST 8731-74

RD 24.200.13-90

TU 14-3-460-75

Designations(see section 4):

D-4.5: D - point unacceptable defect; 4.5 - location depth (mm);

BD-0-60: BD - extended unacceptable defect; 0 - defect on the outer surface;

60 - conventional length (mm);

RA< 10: РА - допустимое расслоение, < 10 - эквивалентная площадь (мм 2);

2A-8: 2A - two point permissible defects; 8 - location depth (mm).

Ultrasonic pipe inspection map (pipe scan? 89? 4.5)

Legend:

x - point defect, ?-? (?- - -?) - extended external (internal) defect.

Business name

CONCLUSION
according to the results of ultrasonic testing of pipes

Order No.:__________________________________________________________________________

No. of pipes______________________________________________________________________________

Standard, TU________________________________________________________________

Material ___________________ Diameter? wall thickness _____________________

Pipe length_______________________________________________________________

NTD for ultrasonic testing: GOST 17410, RD 24.200.13-90

Control results

1. Pipe wall thickness: from _______________________ to _____________________ mm

(complies with, does not comply with the requirements of the standard, specifications)

2. Longitudinal defects ______________________________________________________________

___________________________________________________________________________

3. Transverse defects ______________________________________________________________

(absent, available - give a list)

4. Point defects ____________________________________________________________

(absent, available - give a list)

5. Layers ______________________________________________________________

(absent, available - give a list)

The pipe is recognized as ____________________________________________________________

(good, defective)

Ultrasonic flaw detector _____________________________________________ Signature (last name)

Head of the NMC laboratory ________________________________ Signature (last name)

information data

1. DEVELOPED AND INTRODUCED

All-Union Scientific Research and Design Institute of Chemical and Petroleum Equipment Technology (VNIIPTkhimnefteapparatura)

DEVELOPERS

F.N. Pyshchev (topic leader); V.V. Ryazanov

2. APPROVED AND ENTERED INTO EFFECT by the order of the Ministry of Heavy Engineering dated September 20, 1990 No. AB-002-1-8993

3. Information about the timing and frequency of document verification:

The first inspection date was 1995, inspection frequency was 5 years.

4 INTRODUCED FOR THE FIRST TIME

5. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

	Number of clause, subclause, enumeration, appendix
GOST 12.1.001-83	2.2; 2.3; 2.4; 4.7 - 4.8
GOST 12.1.004-85
GOST 12.1.005-88	1.1; 1.5; 1.6; 1.7; 1.8; 1.9; 1.10; 1.11
GOST 12.1.030-81	1.1; 1.1.1 - 1.1.2; 1.2 - 1.9
GOST 12.2.007.14-75
GOST 1050-74
GOST 2789-75
GOST 14782-86
GOST 17410-78
GOST 20010-74
GOST 20415-82
GOST 23667-78	4.1 - 4.7; 5.1 - 5.4
OST 26-291-87
TU 14-3-460-75
OST 108.885.01-83	1; 2; 5; 6.1; 7; 11


Rules for the design and safe operation of pressure vessels (1987)
Rules for the technical operation of consumer electrical installations and Safety Rules for the operation of consumer electrical installations (1984)	E 1.1.1; E 1.1.3; E 1.3.1; E 2.13.2; B 1.1.1; B 1.1.2; B 1.1.6; B 1.1.7
Sanitary standards and rules for working with equipment that creates ultrasound transmitted by contact to the hands of workers (1980)

1. General Provisions. 1

2. Equipment. 2

2.1. Flaw detectors and converters. 2

2.2. Standard samples.. 2

3. Preparation for control.. 5

3.1. General provisions. 5

3.2. Requirements for flaw detectors... 5

3.3. Requirements for the control area. 6

3.4. Surface preparation under control. 6

3.5. Selecting control parameters and setting up the flaw detector. 7

4. Carrying out ultrasonic testing. eleven

4.1. General provisions. eleven

4.2. Methodology for monitoring longitudinal defects. eleven

4.3. Methodology for monitoring transverse defects. 12

4.4. Delamination control technique. 13

4.5. Registration of defects. 13

4.6. Method for controlling wall thickness. 15

5. Evaluation of ultrasonic testing results. 15

6. Irrigation of control results. 15

7. Safety precautions for ultrasonic testing. 15

Appendix 1. Methods for mating the surfaces of the transducer and pipe.. 17

Appendix 2. Types of contact media. 20

Regulation 3. Regulatory requirements for pipes for ultrasonic testing and assessment of metal continuity. 21

Appendix 4. Determination of labor intensity of control. 22

Appendix 5. Journal of ultrasonic inspection of pipes. 23

Appendix 6. Conclusion based on the results of ultrasonic inspection of pipes. 25

Information data. 25

Monitoring the technical condition of gas pipelines is an important and responsible task. Their damage and breakthroughs can lead to man-made disasters with serious environmental consequences, financial losses and disruptions in industrial activities.

Welds at the joints of steel sections in pipelines are the most vulnerable point of the structure. Moreover, their strength does not depend on the age or novelty of the connection. They require constant monitoring of tightness.

The walls of the pipes are less vulnerable, but during operation they are subject to pressure and aggressive effects from the distilled substances from the inside and adverse external influences from the outside. As a result, even durable materials and reliable protective coatings can become damaged, deformed, deteriorate and collapse over time.

Ultrasonic testing of pipelines is used for monitoring and timely detection of defects. With its help, you can detect even the smallest or hidden imperfections in seam joints or pipe walls.

What is this technology based on?

The ultrasonic diagnostic method is based on acoustic wave vibrations, indistinguishable to human hearing, their registration and instrumental analysis. These waves travel through the metal at a certain speed. If it contains voids, the speed changes and is determined by instruments, as well as deviations in the movement of the wave flow due to encountered obstacles or places of structural heterogeneity of the material. The characteristics of acoustic waves can also be used to understand the shape and size of defects and their location.

How is ultrasonic testing of gas pipelines carried out?

When carrying out monitoring in automatic mode, infrasound systems are used that operate on the basis of hardware and software methods. Devices for collecting acoustic information, installed in groups along the pipeline at a certain distance from each other, transmit it via communication channels to control centers for integration, processing and analysis. The number, coordinates and parameters of detected flaws or leaks are recorded. The signal results are monitored by specialists on the monitor.

An automated infrasound monitoring system for pipelines allows for continuous remote verification of their operation, monitoring and control in real time with the ability to diagnose hard-to-reach areas and gas distribution compartments, using a combination of several monitoring methods simultaneously for greater accuracy of the result and prompt detection of defects and leaks. This is modern high-class equipment.

Pressure and temperature sensors, flow meters and meters of other parameters can also be connected to the system to obtain information about the technological processes occurring in the pipeline.

Advantages of the method:

Ultrasonic inspection is a gentle and non-destructive inspection of pipelines,
has high sensitivity and diagnostic accuracy,
minimum time to detect leaks of gas or other substances,
possibility of remote monitoring,
safety,
convenience and ease of installation and operation of the system,
the inspection does not stop or affect the process of technical operation of the pipeline,
suitable for all types of materials from which pipes are made,
can be used for above-ground and underground pipe laying,
can be carried out in any climatic conditions,
beneficial in terms of economic costs.

Our company's proposals for pipeline monitoring.

High-quality monitoring of the condition of pipelines is a guarantee of their safe operation, reliable operation and insurance against damage. It is ensured thanks to the reliability and efficiency of the equipment used.

The SMIS Expert company develops diagnostic instruments and monitoring systems using modern scientific knowledge and innovative technologies. The use of such systems in practice ensures a high level and accuracy of monitoring the integrity of main pipelines, timely detection of any types of defects and prevention of emergency situations.

Take advantage of our services for the professional organization of ultrasonic testing of gas pipelines and other objects of increased importance when you need experience, a responsible approach and an impeccable result.

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