Over a long period of use, pipelines are exposed to negative external and internal environmental influences. As a result, the metal degrades, corrosion formations form on it, cracks and chips appear, and other types of defects. It would seem that when creating a pipeline project using modern technologies, complete protection of main communications should be ensured.

But, unfortunately, it is impossible to completely exclude the occurrence of damage. To prevent small defects from becoming a serious problem, various types of control are used.

One of them, which does not involve the removal of the main system for repair, is pipeline flaw detection.

This diagnostic method has become widespread. Its use makes it possible to identify the following types of defects:

• loss of tightness level;
• loss of control over the state of tension;
• violation of welded joints;
• depressurization of welds are other parameters that are responsible for the reliable functioning of highways.

You can check this way:

• heating network;
• gas supply network;
• oil pipelines;
• water supply pipelines, etc.

Flaw detection is 100% capable of identifying deficiencies and preventing serious accidents. , and new models of flaw detectors are being tested. Plus, to all this, various analyzes are carried out in order to subsequently improve the performance of the funds.

Ultrasonic flaw detection

Ultrasonic flaw detection of pipelines was first provided by S.Ya. Sokolov. in 1928. It was created based on the study of the movement of ultrasonic vibrations,
which were under the control of a flaw detector.

When describing the operating principle of these devices, it should be noted that the sound wave does not change the direction of its movement in a medium that has the same structure. When a medium is separated by a specific acoustic obstacle, a wave is reflected.

The higher the number of such obstacles, the more waves will be reflected from the boundary that separates the medium. The ability to detect small defects separately from one another determines the length of the sound wave. And it depends on how frequent the sound vibrations are.

The diverse tasks faced during ultrasonic flaw detection have led to the fact that there are great opportunities for this method of troubleshooting. Of these, there are five main options:

1. Echo - location.
2. Shadow method.
3. Mirror-shadow.
4. Mirror.
5. Delta is a way.

Today's ultrasonic inspection instruments are equipped with several measurement options at the same time. And they do this in different combinations.

These mechanisms are distinguished by very high accuracy, as a result, the residual spatial resolution and the reliability of the final conclusion about the defectiveness of the pipeline or its parts are obtained as truthfully as possible.

Ultrasound analysis does not cause damage of the investigated design, and makes it possible to carry out all work with the fastest possible and without harm to human health.

Ultrasonic flaw detection is an accessible in all respects system for monitoring joints and seams. The fact that this method is based on a high possibility of penetration of ultrasonic waves through the metal.

Weld analysis

When they come into contact with liquid, they simply pass it through. This method makes it possible to detect hidden problem formations. This procedure is carried out in accordance with GOST 1844-80.

Often used for this type of verification magnetic flaw detection. It is based on the phenomenon of electromagnetism. The mechanism creates a magnetic field near the area being tested. Its lines pass freely through the metal, but when damage is present, the lines lose their evenness.

Video: Carrying out in-line diagnostics of main pipelines

To record the resulting image, magnetographic or magnetic particle flaw detection is used. If powder is used, it is applied dry or in the form of a wet mass (oil is added to it). The powder will accumulate only in problem areas.

In-line inspection

In-line flaw detection of main pipelines is the most effective option for detecting problems, based on running special devices through the pipe system.

They became in-line flaw detectors, with installed special devices. These mechanisms determine the configurational features of the cross section, identifying dents, thinning and corrosion formations.

There are also in-pipe mechanisms that are designed to solve specific tasks. For example, equipment equipped with video and photographic cameras inspects the interior of the highway and determines the degree of curvature and profile of the structure. It also detects cracks.

These units move through the system in a stream and are equipped with a variety of sensors; they accumulate and store information.

In-line flaw detection of main pipelines has significant advantages. It does not require the installation of devices that conduct systematic monitoring.

To the above, it must be added that using this type of diagnostics, it is possible to regularly monitor deformation changes throughout the entire section of the existing structure with a high level of productivity.

In this way, it is possible to timely identify the area that poses an emergency threat to the entire system, and timely carry out repair work to eliminate problems.

Speaking about this method, it is important to note that there are a number of technical difficulties in its implementation. The main thing is that it is expensive. And the second factor is the availability of devices only for main pipelines with large volumes.

For these reasons, this method is most often used for relatively new gas pipeline systems. This method can be implemented for other highways through reconstruction.

In addition to the specified technical difficulties, this method is distinguished by the most accurate indicators with the processing of verification data.

When examining main pipelines, it is not necessary to follow all the procedures to ensure that there are no problems. Each section of the highway can be checked in one or another most appropriate way.

To choose the optimal verification option, you need to evaluate how important the responsibility of the joint is. And already, based on this, select a research method. For example, for home production, a visual inspection or other budgetary types of inspections are often sufficient.

In the construction industry, pipes with a diameter of 28 to 1420 mm and a wall thickness of 3 to 30 mm are used. Based on flaw detection, the entire range of pipe diameters can be divided into three groups:

1. 28...100 mm and H = 3...7 mm
2. 108...920 mm and H= 4...25 mm
3. 1020...1420 mm and H= 12...30 mm

Carried out by specialists of the Moscow State Technical University. N.E. Bauman's research shows that it is necessary to take into account the anisotropy of the elastic properties of the material when developing methods for ultrasonic testing of welded pipe joints.

Peculiarities of anisotropy of pipe steel.

It is assumed that the speed of propagation of transverse waves does not depend on the direction of sounding and is constant over the cross section of the pipe wall. But ultrasonic testing of welded joints of main gas pipelines made from foreign and Russian pipes revealed a significant level of acoustic noise, the omission of large root defects, as well as incorrect assessment of their coordinates.

It has been established that, subject to optimal control parameters and compliance with the testing procedure, the main reason for missing a defect is the presence of a noticeable anisotropy in the elastic properties of the base material, which affects the speed, attenuation, and deviation from straightness of the ultrasonic beam propagation.

Having sounded the metal of more than 200 pipes according to the scheme shown in Fig. 1, it was revealed that the standard deviation of the wave speed for a given direction of propagation and polarization is 2 m/s (for transverse waves). Deviations of speeds from the table ones by 100 m/s or more are not accidental and are most likely associated with the production technology of rolled products and pipes. Deviations on such scales significantly affect the propagation of polarized waves. In addition to the described anisotropy, inhomogeneity of the speed of sound across the thickness of the pipe wall was revealed.

Rice. 1. Designations of deposits in the pipe metal: X, Y, Z. - directions of ultrasound propagation: x. y.z: - polarization directions; Y - rolling direction: Z - perpendicular to the plane of the pipe

Rolled sheets have a layered texture, consisting of fibers of metal and non-metallic inclusions, elongated during deformation. Sheet zones of unequal thickness are subject to various deformations as a result of the influence of the thermomechanical rolling cycle on the metal. This leads to the fact that the speed of sound is additionally affected by the depth of the sounding layer.

Inspection of welded seams of pipes of various diameters.

Pipes with a diameter of 28...100 mm.

Welded seams in pipes with a diameter of 28 to 100 mm and a height of 3 to 7 mm have such a feature as the formation of sagging inside the pipe, this, when inspected with a direct beam, leads to the appearance of false echo signals on the screen of the flaw detector, which coincide in time with the echo signals, reflected from root defects, which are detected by a single reflected beam. Since the effective width of the beam is commensurate with the thickness of the pipe wall, the reflector usually cannot be found by the location of the finder relative to the reinforcement roller. There is also an uncontrolled zone in the center of the seam due to the large width of the seam bead. All this leads to the fact that the probability of detecting unacceptable volumetric defects is low (10-12%), but unacceptable planar defects are determined much more reliably (~ 85%). The main parameters of sagging (width, depth and angle of contact with the surface of the product) are considered random variables for a given pipe size; the average parameter values ​​are 6.5 mm; 2.7 mm and 56°30" respectively.

Rolled steel behaves as an inhomogeneous and anisotropic medium with rather complex dependences of the velocities of elastic waves on the direction of sounding and polarization. The change in sound speed is closely symmetrical relative to the middle of the sheet section, and near this middle the transverse wave speed can decrease significantly (up to 10%) relative to the surrounding areas. The shear wave speed in the objects under study varies in the range of 3070...3420 m/s. At a depth of up to 3 mm from the surface of the rolled product, a slight (up to 1%) increase in the shear wave speed is likely.

The noise immunity of control is significantly enhanced when using inclined separate-combined probes of the RSN type (Fig. 2), called chord probes. They were created at MSTU. N.E. Bauman. The peculiarity of the inspection is that when identifying defects, transverse scanning is not necessary; it is only needed along the perimeter of the pipe when the front face of the transducer is pressed against the seam.

Rice. 2. Inclined chord RSN-PEP: 1 - emitter: 2 - receiver

Pipes with a diameter of 108...920 mm.

Pipes with a diameter of 108-920 mm and with H in the range of 4-25 mm are also performed by one-sided welding without back welding. Until recently, control over these connections was controlled by combined probes according to the methodology outlined for pipes with a diameter of 28-100 mm. But the known control technique assumes the presence of a significantly large zone of coincidence (zone of uncertainty). This leads to insignificant reliability of assessing the quality of the connection. Combined probes have a high level of reverberation noise, which complicates the decoding of signals, and uneven sensitivity, which cannot always be compensated for by available means. The use of chordal separate-combined probes for monitoring a given standard size of welded joints is not effective due to the fact that due to the limited values ​​of the input angles of ultrasonic vibrations from the surface of the welded joint, the dimensions of the transducers increase disproportionately, and the area of ​​acoustic contact increases.

Created at MSTU. N.E. Bauman inclined probes with equalized sensitivity are used to control welded joints with a diameter of more than 10 cm. Equalization of sensitivity is achieved by choosing a rotation angle of 2 so that the middle and upper part of the weld is sounded by a central, single-reflected beam, and the lower part is examined by direct peripheral rays incident on the defect at an angle Y, from central. In Fig. 3. shows a graph of the dependence of the angle of input of the transverse wave on the angle of rotation and opening of the directional pattern Y. Here in the probe, the waves incident and reflected from the defect are horizontally polarized (SH-wave).

Rice. 3. Changing the input angle alpha, within the limit of half the opening angle of the RSN-PEP radiation pattern, depending on the rotation angle delta.

The graph shows that when testing products H = 25 mm, the uneven sensitivity of the RS-probe can be up to 5 dB, and for a combined probe it can reach 25 dB. RS-PEP has an increased signal level and has increased absolute sensitivity. The RS-PEP clearly reveals a notch with an area of ​​0.5 mm2 when inspecting a welded joint 1 cm thick with both a direct and a single reflected beam at a useful signal/interference ratio of 10 dB. The process of monitoring the considered probes is similar to the procedure for conducting combined probes.

Pipes with a diameter of 1020...1420 mm.

To make welded joints of pipes with a diameter of 1020 and 1420 mm with H in the range from 12 to 30 mm, double-sided welding or welding with back welding of the seam bead is used. In seams made by double-sided welding, false signals from the trailing edge of the reinforcement bead most often have less interference than in single-sided welds. They are smaller in amplitude due to the smoother contours of the roller further along the sweep. In this regard, this is the most convenient pipe size for flaw detection. But held in MSTU. N.E. Bauman's research shows that the metal of these pipes is characterized by the greatest anisotropy. In order to minimize the effect of anisotropy on the detection of defects, it is best to use a probe at a frequency of 2.5 MHz with a prism angle of 45°, and not 50°, as advised in most regulatory documents for testing such connections. Higher control reliability was achieved when using RSM-N12 type probes. But unlike the method outlined for pipes with a diameter of 28-100 mm, there is no zone of uncertainty when monitoring these connections. Otherwise, the control principle remains the same. When using the RS-PEP, it is recommended to adjust the scan speed and sensitivity according to vertical drilling. The scanning speed and sensitivity of inclined combined probes should be adjusted using corner reflectors of the appropriate size.

When inspecting welds, it is necessary to remember that metal delamination may occur in the heat-affected zone, which complicates the determination of the coordinates of the defect. The area with a defect found by an inclined probe must be checked with a direct probe to clarify the characteristics of the defect and identify the true value of the depth of the defect.

In the petrochemical industry and nuclear energy, clad steels are widely used for the production of pipelines and vessels. Austenitic steels applied by surfacing, rolling or explosion with a thickness of 5-15 mm are used as cladding for the inner wall of such structures.

The method of monitoring these welded joints involves assessing the continuity of the pearlite part of the weld, including the fusion zone with restorative anti-corrosion surfacing. The continuity of the surfacing body itself is not subject to control.

But due to the difference in the acoustic properties of the base metal and austenitic steel from the interface during ultrasonic testing, echo signals appear that interfere with the detection of defects such as cladding delaminations and sub-cladding cracks. The presence of cladding significantly affects the parameters of the acoustic path of the probe.

In this regard, standard technological solutions for monitoring thick-walled welds of clad pipelines do not give the desired result.

Long-term research by a number of specialists: V.N. Radko, N.P. Razygraeva, V.E. Bely, V.S. Grebennik and others made it possible to determine the main features of the acoustic path, develop recommendations for optimizing its parameters, and create a technology for ultrasonic testing of welds with austenitic cladding.

In the works of specialists, it was established that when a beam of ultrasonic waves is re-reflected from the pearlite-austenitic cladding boundary, the directional pattern almost does not change in the case of rolling cladding and is significantly deformed in the case of surfacing cladding. Its width increases sharply, and within the main lobe oscillations of 15-20 dB appear, depending on the type of surfacing. There is a significant displacement of the reflection exit point from the beam cladding boundary compared to its geometric coordinates and a change in the speed of transverse waves in the transition zone.

Taking these features into account, the technology for monitoring welded joints of clad pipelines requires preliminary mandatory measurement of the thickness of the pearlite part.

Better detection of planar defects (cracks and lack of fusion) is achieved by using a probe with an input angle of 45° and a frequency of 4 MHz. The better detection of vertically oriented defects at an input angle of 45° compared to angles of 60 and 70° is due to the fact that when the latter are sounded, the angle at which the beam meets the defect is close to the 3rd critical angle, at which the shear wave reflection coefficient is the smallest.

At a frequency of 2 MHz, when sounded outside the pipe, echoes from defects are shielded by an intense and long-lasting noise signal. The noise immunity of the probe at a frequency of 4 MHz is on average 12 dB higher, which means the useful signal from a defect located in the immediate vicinity of the surfacing boundary will be better resolved against the background noise.

When sounding from inside the pipe through the surfacing, maximum noise immunity is established when the probe is set to a frequency of 2 MHz.

The method of monitoring pipeline welds with surfacing is regulated by the Gosatomnadzor guidelines document RFPNAEG-7-030-91.

GOST 17410-78

Group B69

INTERSTATE STANDARD

TESTING NON-DESTRUCTIVE

SEAMLESS CYLINDRICAL METAL PIPES

Ultrasonic flaw detection methods

Non-destructive testing. Metal seamless cylindrical pipes and tubes. Ultrasonic methods of detection

ISS 19.100
23.040.10

Date of introduction 1980-01-01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Heavy, Energy and Transport Engineering of the USSR

2. APPROVED AND ENTERED INTO EFFECT by Resolution of the USSR State Committee for Standards dated 06.06.78 N 1532

3. REPLACE GOST 17410-72

4. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

	Number of paragraph, subparagraph

5. The validity period was lifted according to Protocol No. 4-93 of the Interstate Council for Standardization, Metrology and Certification (IUS 4-94)

6. EDITION (September 2010) with Amendments No. 1, approved in June 1984, July 1988 (IUS 9-84, 10-88)


This standard applies to straight metal single-layer seamless cylindrical pipes made of ferrous and non-ferrous metals and alloys, and establishes methods for ultrasonic flaw detection of pipe metal continuity to identify various defects (such as violation of the continuity and homogeneity of the metal) located on the outer and inner surfaces, as well as in the thickness of the pipe walls and detected by ultrasonic flaw detection equipment.

The actual dimensions of defects, their shape and nature are not established by this standard.

The need for ultrasonic testing, its scope and the norms of unacceptable defects should be determined in the standards or specifications for pipes.

1. EQUIPMENT AND REFERENCE SAMPLES

1.1. In the control use: ultrasonic flaw detector; converters; standard samples, auxiliary devices and fixtures to ensure constant control parameters (input angle, acoustic contact, scanning step).

The form of a standard sample passport is given in Appendix 1a.

1.2. It is allowed to use equipment without auxiliary devices and devices to ensure constant control parameters when moving the transducer manually.

1.3. (Deleted, Amendment No. 2).

1.4. The identified pipe metal defects are characterized by equivalent reflectivity and conditional dimensions.

1.5. The nomenclature of the parameters of the transducers and methods for their measurement - according to GOST 23702.

1.6. With the contact method of control, the working surface of the transducer is rubbed on the surface of the pipe with an outer diameter of less than 300 mm.

Instead of lapping transducers, it is allowed to use nozzles and supports when testing pipes of all diameters with transducers with a flat working surface.

1.7. A standard sample for adjusting the sensitivity of ultrasonic equipment during testing is a section of a defect-free pipe made of the same material, the same size and having the same surface quality as the pipe being tested, in which artificial reflectors are made.

Notes:

1. For pipes of the same range, differing in surface quality and material composition, it is allowed to manufacture uniform standard samples if, with the same equipment settings, the amplitudes of the signals from reflectors of the same geometry and the level of acoustic noise coincide with an accuracy of at least ±1.5 dB.

2. A maximum deviation of the dimensions (diameter, thickness) of standard samples from the dimensions of the controlled pipe is allowed if, with unchanged equipment settings, the amplitudes of the signals from artificial reflectors in the standard samples differ from the amplitude of the signals from artificial reflectors in standard samples of the same standard size as the controlled pipe, no more than ±1.5 dB.

3. If the metal of the pipes is not uniform in attenuation, then it is allowed to divide the pipes into groups, for each of which a standard sample of metal with maximum attenuation must be made. The method for determining attenuation must be specified in the technical documentation for control.

1.7.1. Artificial reflectors in standard samples for adjusting the sensitivity of ultrasonic equipment for monitoring longitudinal defects must correspond to Figures 1-6, for monitoring transverse defects - Figures 7-12, for monitoring defects such as delamination - Figures 13-14.

Note. It is allowed to use other types of artificial reflectors provided for in the technical documentation for control.

1.7.2. Artificial reflectors such as marks (see Fig. 1, 2, 7, 8) and rectangular groove (see Fig. 13) are used mainly for automated and mechanized control. Artificial reflectors such as a segmented reflector (see drawings 3, 4, 9, 10), notches (see drawings 5, 6, 11, 12), flat-bottomed holes (see drawing 14) are used mainly for manual control. The type of artificial reflector and its dimensions depend on the control method and the type of equipment used and must be provided for in the technical documentation for control.

Damn.1

Damn.3

Damn.8

Damn.11

1.7.3. Rectangular risks (Fig. 1, 2, 7, 8, version 1) are used to control pipes with a nominal wall thickness equal to or greater than 2 mm.

Triangular-shaped risks (Fig. 1, 2, 7, 8, version 2) are used to control pipes with a nominal wall thickness of any size.

(Changed edition, Amendment No. 1).

1.7.4. Corner reflectors of the segment type (see drawings 3, 4, 9, 10) and notches (see drawings 5, 6, 11, 12) are used for manual inspection of pipes with an outer diameter of more than 50 mm and a thickness of more than 5 mm.

1.7.5. Artificial reflectors in standard samples such as a rectangular groove (see Figure 13) and flat-bottomed holes (see Figure 14) are used to adjust the sensitivity of ultrasonic equipment to detect defects such as delaminations with a pipe wall thickness greater than 10 mm.

1.7.6. It is allowed to manufacture standard samples with several artificial reflectors, provided that their location in the standard sample prevents their mutual influence on each other when adjusting the sensitivity of the equipment.

1.7.7. It is allowed to produce composite standard samples consisting of several sections of pipes with artificial reflectors, provided that the boundaries of connecting the sections (by welding, screwing, tight fitting) do not affect the sensitivity setting of the equipment.

1.7.8. Depending on the purpose, manufacturing technology and surface quality of the pipes being monitored, one of the standard sizes of artificial reflectors, determined by the rows, should be used:

For the scratches:

Depth of notch, % of pipe wall thickness: 3, 5, 7, 10, 15 (±10%);

- length of marks, mm: 1.0; 2.0; 3.0; 5.0; 10.0; 25.0; 50.0; 100.0 (±10%);

- width of the mark, mm: no more than 1.5.

Notes:

1. The length of the mark is given for its part that has a constant depth within the tolerance; the entry and exit areas of the cutting tool are not taken into account.

2. Rounding risks associated with the technology of its manufacture are allowed at the corners, not more than 10%.


For segment reflectors:

- height, mm: 0.45±0.03; 0.75±0.03; 1.0±0.03; 1.45±0.05; 1.75±0.05; 2.30±0.05; 3.15±0.10; 4.0±0.10; 5.70±0.10.

Note. The height of the segment reflector must be greater than the length of the transverse ultrasonic wave.


For notches:

- height and width must be greater than the length of the transverse ultrasonic wave; the ratio must be greater than 0.5 and less than 4.0.

For flat bottom holes:

- diameter 2, mm: 1.1; 1.6; 2.0; 2.5; 3.0; 3.6; 4.4; 5.1; 6.2.

The distance of the flat bottom of the hole from the inner surface of the pipe should be 0.25; 0.5; 0.75, where is the pipe wall thickness.

For rectangular slots:

width, mm: 0.5; 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.0; 5.0; 10.0; 15.0 (±10%).

The depth should be 0.25; 0.5; 0.75, where is the pipe wall thickness.

Note. For flat-bottomed holes and rectangular grooves, other depth values ​​are allowed, provided in the technical documentation for control.


The parameters of artificial reflectors and methods for testing them are indicated in the technical documentation for control.

(Changed edition, Amendment No. 1).

1.7.9. The height of the macro-irregularities of the surface relief of the standard sample should be 3 times less than the depth of the artificial corner reflector (marks, segmental reflector, notches) in the standard sample, according to which the sensitivity of the ultrasonic equipment is adjusted.

1.8. When inspecting pipes with a wall thickness to outer diameter ratio of 0.2 or less, artificial reflectors on the outer and inner surfaces are made of the same size.

When inspecting pipes with a large ratio of wall thickness to outer diameter, the dimensions of the artificial reflector on the inner surface should be established in the technical documentation for inspection, however, it is allowed to increase the dimensions of the artificial reflector on the inner surface of the standard sample, compared to the dimensions of the artificial reflector on the outer surface of the standard sample, without more than 2 times.

1.9. Standard samples with artificial reflectors are divided into control and working ones. Ultrasonic equipment is set up using standard working samples. Control samples are intended to test working standard samples to ensure the stability of control results.

Control standard samples are not produced if working standard samples are checked by directly measuring the parameters of artificial reflectors at least once every 3 months.

The compliance of the working sample with the control sample is checked at least once every 3 months.

Working reference materials that are not used within the specified period are checked before their use.

If the amplitude of the signal from the artificial reflector and the level of acoustic noise of the sample differs from the control by ±2 dB or more, it is replaced with a new one.

(Changed edition, Amendment No. 1).

2. PREPARATION FOR CONTROL

2.1. Before inspection, the pipes are cleaned of dust, abrasive powder, dirt, oils, paint, flaking scale and other surface contaminants. Sharp edges at the end of the pipe should not have burrs.

The need to number pipes is established depending on their purpose in the standards or technical specifications for pipes of a particular type. By agreement with the customer, pipes may not be numbered.

(Changed edition, Amendment No. 2).

2.2. Pipe surfaces must not have peeling, dents, nicks, cutting marks, leaks, splashes of molten metal, corrosion damage and must meet the surface preparation requirements specified in the technical documentation for inspection.

2.3. For mechanically processed pipes, the roughness parameter of the outer and inner surfaces according to GOST 2789 is 40 microns.

(Changed edition, Amendment No. 1).

2.4. Before testing, the compliance of the main parameters with the requirements of the technical documentation for control is checked.

The list of parameters to be checked, the methodology and frequency of their checking must be provided in the technical documentation for the ultrasonic testing equipment used.

2.5. The sensitivity of ultrasonic equipment is adjusted using working standard samples with artificial reflectors shown in Figures 1-14 in accordance with the technical documentation for control.

Setting the sensitivity of automatic ultrasonic equipment using working standard samples must meet the conditions of production inspection of pipes.

2.6. The adjustment of the sensitivity of automatic ultrasonic equipment according to a standard sample is considered complete if 100% registration of the artificial reflector occurs when the sample is passed through the installation no less than five times in a steady state. In this case, if the design of the pipe-drawing mechanism allows, the standard sample is rotated each time by 60-80° relative to the previous position before being inserted into the installation.

Note. If the mass of the standard sample is more than 20 kg, it is allowed to pass the section of the standard sample with an artificial defect five times in the forward and reverse directions.

3. CONTROL

3.1. When monitoring the quality of pipe metal continuity, the echo method, shadow or mirror-shadow methods are used.

(Changed edition, Amendment No. 1).

3.2. Ultrasonic vibrations are introduced into the pipe metal by immersion, contact or slot methods.

3.3. The applied circuits for switching on the converters during monitoring are given in Appendix 1.

It is allowed to use other schemes for switching on the converters, given in the technical documentation for control. The methods of switching on the transducers and the types of excited ultrasonic vibrations must ensure reliable detection of artificial reflectors in standard samples in accordance with paragraphs 1.7 and 1.9.

3.4. Inspection of pipe metal for the absence of defects is achieved by scanning the surface of the pipe being inspected with an ultrasonic beam.

The scanning parameters are set in the technical documentation for testing, depending on the equipment used, the testing scheme and the size of the defects to be detected.

3.5. To increase the productivity and reliability of control, the use of multi-channel control schemes is allowed, while the transducers in the control plane must be located so as to exclude their mutual influence on the control results.

The equipment is configured according to standard samples for each control channel separately.

3.6. Checking the correctness of the equipment settings using standard samples should be carried out every time the equipment is turned on and at least every 4 hours of continuous operation of the equipment.

The frequency of inspection is determined by the type of equipment used, the control circuit used and should be established in the technical documentation for control. If a setting violation is detected between two inspections, the entire batch of inspected pipes is subject to re-inspection.

It is allowed to periodically check the equipment settings during one shift (no more than 8 hours) using devices whose parameters are determined after setting up the equipment according to a standard sample.

3.7. The method, basic parameters, circuits for switching on the transducers, the method of introducing ultrasonic vibrations, the sounding circuit, methods for separating false signals and signals from defects are established in the technical documentation for control.

The form of the ultrasonic inspection chart for pipes is given in Appendix 2.

3.6; 3.7. (Changed edition, Amendment No. 1).

3.8. Depending on the material, purpose and manufacturing technology, pipes are checked for:

a) longitudinal defects during the propagation of ultrasonic vibrations in the pipe wall in one direction (adjustment using artificial reflectors, Fig. 1-6);

b) longitudinal defects when ultrasonic vibrations propagate in two directions towards each other (adjustment using artificial reflectors, Fig. 1-6);

c) longitudinal defects when ultrasonic vibrations propagate in two directions (tuning using artificial reflectors, Fig. 1-6) and transverse defects when ultrasonic vibrations propagate in one direction (tuning using artificial reflectors, Fig. 7-12);

d) longitudinal and transverse defects during the propagation of ultrasonic vibrations in two directions (adjustment using artificial reflectors Fig. 1-12);

e) defects such as delaminations (adjustment using artificial reflectors (Fig. 13, 14) in combination with subparagraphs a B C D.

3.9. During the control, the sensitivity of the equipment is adjusted so that the amplitudes of the echo signals from the external and internal artificial reflectors differ by no more than 3 dB. If this difference cannot be compensated by electronic devices or methodological techniques, then the pipes are checked for internal and external defects using separate electronic channels.

4. PROCESSING AND REGISTRATION OF CONTROL RESULTS

4.1. The assessment of the continuity of the pipe metal is carried out based on the results of the analysis of the information obtained as a result of the control, in accordance with the requirements established in the standards or specifications for pipes.

Information processing can be performed either automatically using the appropriate devices included in the control installation, or by a flaw inspector according to visual observation data and measured characteristics of the detected defects.

4.2. The main measured characteristic of defects, according to which pipes are graded, is the amplitude of the echo signal from the defect, which is measured by comparison with the amplitude of the echo signal from an artificial reflector in a standard sample.

Additional measured characteristics used in assessing the quality of pipe metal continuity, depending on the equipment used, the scheme and method of control and artificial tuning reflectors, the purpose of the pipes, are indicated in the technical documentation for control.

4.3. The results of ultrasonic testing of pipes are entered in the registration log or in conclusion, where the following should be indicated:

- pipe size and material;

- scope of control;

- technical documentation based on which control is performed;

- control circuit;

- an artificial reflector, according to which the sensitivity of the equipment was adjusted during the control;

- numbers of standard samples used when setting up;

- type of equipment;

- nominal frequency of ultrasonic vibrations;

- converter type;

- scanning parameters.

Additional information to be recorded, the procedure for issuing and storing a journal (or conclusion), methods for fixing identified defects should be established in the technical documentation for control.

The form of the ultrasonic pipe inspection log is given in Appendix 3.

(Changed edition, Amendment No. 1).

4.4. All repaired pipes must undergo repeated ultrasonic testing in full, as specified in the technical documentation for testing.

4.5. Entries in the journal (or conclusion) serve to constantly monitor compliance with all the requirements of the standard and technical documentation for control, as well as for statistical analysis of the effectiveness of pipe control and the state of the technological process of their production.

5. SAFETY REQUIREMENTS

5.1. When carrying out work on ultrasonic testing of pipes, the flaw detector operator must be guided by the current "Rules for the technical operation of electrical installations of consumers and the rules for technical safety during the operation of electrical installations of consumers" * approved by the State Energy Supervision Authority on April 12, 1969 with additions of December 16, 1971 and agreed with the All-Russian Central Council of Trade Unions on April 9, 1969.
________________
* The document is not valid on the territory of the Russian Federation. The Rules for the technical operation of consumer electrical installations and the Intersectoral labor protection rules (safety rules) for the operation of electrical installations (POT R M-016-2001, RD 153-34.0-03.150-00) apply. - Database manufacturer's note.

5.2. Additional requirements for safety and fire fighting equipment are established in the technical documentation for control.

With the echo method of control, combined (Fig. 1-3) or separate (Fig. 4-9) circuits for switching on transducers are used.

When combining the echo method and the mirror-shadow method of control, a separate-combined scheme for switching on transducers is used (Fig. 10-12).

With the shadow method of control, a separate (Fig. 13) circuit for switching on converters is used.

With the mirror-shadow method of control, a separate (Fig. 14-16) circuit for switching on converters is used.

Note to drawings 1-16: G- output to the generator of ultrasonic vibrations; P- output to the receiver.

Damn.4

Damn.6

Damn.16

APPENDIX 1. (Changed edition, Rev. N 1)

APPENDIX 1a (for reference). Passport for a standard sample

APPENDIX 1a
Information

PASSPORT
per standard sample N

	Name of the manufacturer
	Date of manufacture
	Assignment of a standard sample (working or control)
	Material grade
	Pipe size (diameter, wall thickness)
	Type of artificial reflector according to GOST 17410-78
	Reflector orientation type (longitudinal or transverse)

Dimensions of artificial reflectors and measurement method:

Reflector type	Application surface	Measuring method	Reflector parameters, mm
Risk (triangular or rectangular)
Segmental reflector
Flat bottom hole					distance
Rectangular groove

	Periodic Check Date
		job title					surname, i., o.

Notes:

1. The passport indicates the dimensions of artificial reflectors that are manufactured in this standard sample.

2. The passport is signed by the heads of the service conducting certification of reference materials and the technical control department service.

3. In the column “Measurement method” the measurement method is indicated: direct, using casts (plastic impressions), using witness samples (amplitude method) and the instrument or device used to carry out the measurements.

4. In the column “Application surface” the internal or external surface of the standard sample is indicated.


APPENDIX 1a. (Introduced additionally, Amendment No. 1).

APPENDIX 2 (recommended). Map of ultrasonic inspection of pipes using manual scanning method

	Number of technical documentation for control
	Pipe size (diameter, wall thickness)
	Material grade
	Number of technical documentation regulating suitability assessment standards
	Volume of control (direction of sound)
	Converter type
	Converter frequency
	Beam angle
	Artificial reflector type and size (or reference number) for adjusting fixation sensitivity
	and search sensitivity
	Type of flaw detector
	Scan parameters (step, control speed)

Note. The map must be drawn up by engineering and technical workers of the flaw detection service and agreed, if necessary, with the interested services of the enterprise (department of the chief metallurgist, department of the chief mechanic, etc.).

Date of con- role			Number of package, presentation, certificate fiqat	If- quality of pipes, pcs.	Control parameters (standard sample number, size of artificial defects, type of installation, control circuit, operating frequency of ultrasonic testing, converter size, control step)	Numbers checked old pipes	Ultrasound testing results		Signature defective scopist (operator) controller) and quality control department
	Once- measures, mm	Mate- rial					pipe numbers without details fects	numbers of pipes with defects tami

APPENDIX 3. (Changed edition, Amendment No. 1).



Electronic document text
prepared by Kodeks JSC and verified against:
official publication
Metal and connecting pipes
parts for them. Part 4. Black pipes
metals and alloys cast and
connecting parts to them.
Basic dimensions. Technological methods
pipe testing: Sat. GOST. -
M.: Standartinform, 2010

The instruction applies to butt girth welded joints of pipes with a diameter of 200 mm or more, a wall thickness of 4 to 20 mm, with a pressure of less than 10 MPa from low-carbon steels St. 10 and steel 20 (GOST 1050-88), made by fusion welding, and establishes requirements for non-destructive testing by the ultrasonic method.

JSC NIICHIMMASH

TESTING NON-DESTRUCTIVE
CIRCULAR SEAMS OF BUTT WELD JOINTS OF PIPES

ULTRASONIC TESTING TECHNIQUE

(Topic #923176)

RDI 26-11-65-96

AGREED:
Deputy quality director	Head of Department No. 23
Bugulma Mechanical Plant	N.V. Khimchenko
VC. Konkin	Head of Sector
"__" ________________ 1997	V.A. Bobrov
	Executor
	V.V. Volokitin

Moscow 1997

INTRODUCTION

This instruction applies to butt welded joints of pipes with a diameter of 200 mm or more, a wall thickness of 4 to 20 mm, with a pressure of less than 10 MPa from low-carbon steels St. 10 and steel 20 (GOST 1050-88), made by fusion welding, and establishes requirements for non-destructive testing by the ultrasonic method.

The standard was developed taking into account the requirements of GOST 14782-86 “Non-destructive testing, welded joints. Ultrasonic methods”, OST 26-2044-83 “Butt and fillet welded joints of pressure vessels and apparatuses”, OST 36-75-83 “Non-destructive testing. Welded connections of pipelines. Ultrasonic method”, SNiP 3.05.05-84, as well as the experience of OAO NIIkhimmash in ultrasonic testing of the pipes mentioned.

After accumulating experience in ultrasonic testing of pipes by the specialists of your enterprise, in 6 - 12 months, based on your materials, OAO NIIkhimmash can agree on changes and additions to this method.

The need to use the ultrasonic method of control and its scope are established by regulatory and technical documentation.

1. PURPOSE OF THE METHOD

1.1. Ultrasonic testing is designed to detect cracks, lack of penetration, lack of fusion, pores, slag inclusions and other types of defects in welds and near-weld zones without deciphering their nature, but indicating the coordinates, conditional dimensions and the number of detected defects.

1.2. Ultrasonic testing is carried out at ambient temperatures from 5 to 40 °C. In cases where the controlled product is heated in the area of ​​the searcher’s movement to temperatures from 5 to 40 °C, testing is permitted at ambient temperatures down to minus 10 °C. In this case, flaw detectors and converters must be used that remain operational (according to the passport data) at temperatures down to minus 10 ° C and below.

1.3. Ultrasonic testing is carried out at any spatial position of the welded joint.

2. REQUIREMENTS FOR DEFECTOSCOPISTS AND ULTRASONIC INSPECTION SITE

2.1. Requirements for ultrasonic flaw detectors.

2.1.1. Ultrasonic testing should be carried out by a team of two flaw detectors.

2.1.2. Persons who have undergone theoretical and practical training in accordance with “ Rules for certification of non-destructive testing specialists,” approved by the Gosgortekhnadzor of Russia, having a second-level certificate for the right to conduct control and issue an opinion on the quality of welds based on the results of ultrasonic testing.

Flaw detectors of the first and second levels must undergo recertification after three years, as well as after a break in work for more than 1 year and when changing places of work.

Certification and re-certification of specialists is carried out in special licensed certification centers.

2.1.3. Ultrasonic testing work must be supervised by technical engineers or flaw detectors with second or third levels of qualification.

2.2. Requirements for the ultrasonic testing area.

2.2.1. The ultrasonic testing area must have production sites that provide workplaces for flaw detectors, equipment and accessories.

2.2.2. The ultrasonic testing area must be provided with:

Ultrasonic flaw detectors with a set of standard and special transducers;

Distribution board from an alternating current network with a frequency of 50 Hz, voltage 220 V ± 10%, 36 V ± 10%, portable power supply blocks, grounding bars;

Standard and test samples, auxiliary devices for checking and adjusting flaw detectors with converters;

Sets of plumbing, electrical and measuring tools, accessories (chalk, colored pencils, paper, paints);

Contact liquid, oil can, cleaning material, seam brush;

Work tables and workbenches;

Racks and cabinets for storing flaw detectors with a set of transducers, samples, materials and documentation.

3. SAFETY REQUIREMENTS

3.1. When working with ultrasonic flaw detectors, it is necessary to comply with safety and industrial sanitation requirements in accordance with GOST 12.2.007-75, SNiP III-4-80, “ Rules for the technical operation of consumer electrical installations And safety regulations for the operation of consumer electrical installations", approved by the State Energy Supervision Authority of the USSR on April 12, 1969, with amendments and additions made, and "Sanitary norms and rules for working with equipment that creates ultrasound transmitted by contact to the hands of workers" No. 2282-80, approved by the Ministry of Health."

3.2. When powered from an alternating current network, ultrasonic flaw detectors must be grounded with a copper wire with a cross-section of at least 2.5 mm 2.

3.3. Connection of flaw detectors to the alternating current network is carried out through sockets installed by an electrician at specially equipped posts.

3.4. Flaw detectors are prohibited from opening a flaw detector connected to a power source and repairing it due to the presence of a high voltage unit.

3.5. It is prohibited to carry out inspections near places where welding work is performed without fencing with light-protective screens.

3.6. It is prohibited to use oil as a contact liquid when carrying out ultrasonic testing near oxygen cutting and welding sites, as well as in rooms for storing oxygen cylinders.

3.7. When carrying out work at heights, in cramped conditions, workplaces must provide the flaw detector with convenient access to the welded joint, subject to safety conditions (construction of scaffolding, scaffolding, use of helmets, mounting belts, special clothing). It is prohibited to carry out inspections without protective devices against the effects of atmospheric precipitation on the flaw detector, equipment and inspection location.

3.8. Flaw detectors must undergo medical examinations at least once a year in accordance with Order No. 555 of the USSR Ministry of Health of September 29, 1989 (Appendix 1, clause 4.5) and Order No. 280/88 of October 5, 1995 of the Ministry of Health and Medical Industry RF (Appendix No. 1, clause 5.5).

3.9. Persons at least 18 years of age who have undergone safety training and are registered in a journal in the prescribed form are allowed to work on ultrasonic flaw detection. Instructions must be carried out periodically within the time limits established by the order of the organization (factory, plant, etc.).

3.10. The administration of the organization conducting ultrasonic testing is obliged to ensure compliance with safety requirements.

3.11. If safety rules are violated, the flaw detector operator must be removed from work and re-admitted to it after additional instructions.

4. PREPARATION FOR CONTROL

4.1. Inspection of butt welded joints with a thickness of 4 - 9 mm is carried out from one surface of the product on both sides of the weld in one pass with a direct and once reflected beam.

4.2. The main control parameters are set in accordance with the technical specifications for pipes. In the absence of technical conditions, be guided by table No. 1 OST 26-2044-83.

4.6. The maximum sensitivity of an ultrasonic flaw detector is adjusted using defects such as segment reflectors or a corner reflector.

When adjusting sensitivity, the sensitivity mode is initially set to high sensitivity. An echo signal is received from the reflector on the direct and reflected beams. The echo signals are then equalized in height and the sensitivity is reduced until the amplitude reaches 30 mm for the direct and reflected beams.

SETTING THE CONTROL ZONE IN THE “SOFT SCAN” MODE

Crap. 1

If the device does not allow you to level the signals, then the sensitivity should be adjusted separately for the direct and reflected beams and the control should be carried out in two passes.

4.7. When searching for defects, the sensitivity increases by 4 - 6 dB, while the noise level on the screen in height should not exceed 5 ÷ 10 mm.

4.8. The DN coordinate for welds with a thickness of 4 to 9 mm is determined if it is necessary to distinguish the interference from the defect signal.

5. CONTROL

5.1. The inspection includes the operations of sounding the weld metal and the heat-affected zone and determining the measured characteristics of defects. Control is carried out by converters having a nominal frequency of 5.0 MHz and an input angle on steel of 70 degrees. (see p. .).

5.2. Sounding of seams is performed using the method of transverse-longitudinal movement of the transducer. The speed of movement of the transducer should be approximately no more than 30 mm/s.

5.3. Acoustic contact of the transducer with the surface on which it moves is ensured through the coupling liquid by lightly pressing the transducer. The stability of the acoustic contact is evidenced by a decrease in the amplitudes of the signals at the trailing edge of the probing pulse, created by the acoustic noise of the transducer, compared to their level when the acoustic contact of the transducer with the surface of the product deteriorates or is absent. Use contact liquids in accordance with OST 26-2044-83.

5.4. Sounding of welded joints and analysis of echo signals in a strobe pulse are carried out at search sensitivity, and determination of the characteristics of identified defects is carried out at rejection levels. Only those echoes observed in the gate pulse are analyzed.

5.5. During the inspection process, it is necessary to check the setting of the flaw detector to the rejection level at least twice a shift.

5.6. At the rejection level, the signal amplitude, conventional length, conventional distance between defects and the number of defects are assessed.

5.7. The seams of welded joints sound with direct and once reflected rays on both sides (Fig. ).

When echoes appear near the trailing or leading edges of the strobe pulse, it should be clarified whether they are the result of reflection of the ultrasonic beam from the amplification bead or sagging at the root of the weld (Fig.). To do this, measure distances L 1 and L 2 - position of the transducers II at which the echo signal from the reflector has the maximum amplitude, and then the transducer is placed on the other side of the seam at the same distances L 1 and L 2 from the reflector - position of the transducers I.

Method of scanning welded joints

a - direct beam; b - reflected beam.

Crap. 2

Scheme for decoding false echoes

a - from sagging at the root of the seam, b - from the seam reinforcement bead

Crap. 3

If there are no defects under the surface of the reinforcement bead or at the root of the seam, echo signals at the edges of the strobe pulse will not be observed. The signals from the amplification roller will be observed strictly at the border of the strobe pulse.

If the echo signal is caused by a reflection from the seam reinforcement roller, then when it is touched with a tampon moistened with contact liquid, the amplitude of the echo signal will change in time with the touch of the tampon.

5.8. In welded joints with a backing ring and a lock, defects such as cracks and lack of penetration are more often observed in the root part of the weld, and slag and gas inclusions can be located in any layer of the deposited metal. The signal from lack of penetration at the root of the seam when sounded by a direct and once reflected beam (Fig. ). The defect coordinate D U corresponds to the wall thickness, and D U indicates the location of the reflector in the half of the seam reinforcement closest to the transducer or in the middle of the reinforcement. In this case, the converter is usually somewhat removed from the seam.

5.9. When monitoring welded joints with a backing ring or lock, “false” signals may appear (Fig.):

From the gap between the wall of the welded joint and the backing ring or “whisker” when connecting the lock (echo signal 1);

From metal or slag floating under the backing ring or “whisker” (echo signal 2);

From the corners of the backing ring or “mustache” (echo signal 3);

From the edge of the seam reinforcement bead (echo 4).

5.10. Echo signals 1 and 2 from a gap or overflow of metal (slag) when measuring the coordinate D X corresponds to the half of the weld reinforcement farthest from the transducer, and the transducer is located close to the weld reinforcement. The DN coordinate in this case corresponds to the wall thickness or is slightly larger (by 1 - 2 mm). The presence of reflectors is not confirmed when sounding from the opposite side of the seam reinforcement, which distinguishes them from cracks and lack of fusion at the root of the seam.

5.11. Echo signal 3 from the corners of the backing ring or “whisker”, as a rule, appears when the weld is sounded along the entire length of the joint and is located in a certain place of the strobe pulse (in the control zone of a single reflected beam), while the coordinate D X corresponds to the reflector, located in the area of ​​the seam reinforcement boundary farthest from the transducer.

If there is a lack of penetration (lack of fusion) at the root of the weld, the signal from the backing ring sharply decreases or is completely absent.

5.12. Echo signal 4 from the boundary of the weld reinforcement appears in the region of the trailing edge of the strobe pulse (mark 2b) when the upper part of the weld is sounded by a single reflected beam, and the coordinate D Y corresponds to double the wall thickness or slightly more than it, and the coordinate D X indicates the far limit of the reinforcement seam When sounding from the opposite side of the weld reinforcement, the location of the reflector is not confirmed and it is recorded as false.

DIAGRAM FOR REFLECTION OF ULTRASONIC VIBRATIONS FROM LACK OF FUNCTION AT THE ROOT OF A WELD (a) AND THE CORRESPONDING OSCILLOGRAM (b)

Crap. 4

SCHEME ULTRASONICWELD CONTROL WITH A CASING RING (a) INTERLOCKED CONNECTIONS (b) AND THE CORRESPONDING OSCILLOGRAM (c)

Crap. 5

6. MANUFACTURE OF TEST SAMPLES

Control samples should be made from pipe sections 20 mm wide and at least 120 mm long. Apply artificial reflectors on the inner and outer sides of the specified samples with a special device for applying a defect such as a corner reflector. It is advisable to choose a tool with a width of 1.5 - 2.0 mm.

7. REJECTION STANDARDS

According to the results of ultrasound control of welded joints pipelines with a pressure of less than 10 MPa (100 kgf / cm 2) are considered to be of high quality if there are no:

a) extended planar defects;

b) volumetric non-extended defects with a reflected signal amplitude corresponding to an equivalent area of ​​1 mm 2 for thicknesses of 4 - 10 mm and 2 mm 2 for thicknesses of 11 - 20 mm.

8. REGISTRATION OF CONTROL RESULTS

8.1. Registration of control results is carried out in accordance with OST 26-2044-83.

8.2. For abbreviated designation of defects, GOST 14782-86 should be used.

APPENDIX No. 1

TECHNOLOGY FOR RESTORATION OF PKN PC TYPE CONVERTERS

In view of the fact that the transducer prisms are made of organic glass and are subject to abrasion, it is desirable for the process of their subsequent restoration not to bring the wear of the protector to the level of the PET body, i.e. the maximum wear from the nominal level is 1.3 - 1.4 mm (the rest is not less than 0.2 mm to the body).

The restoration of the probe is carried out as follows: stripping. The probe is installed on the cover (upside down) in the vise of the milling machine is clamped (not strongly, without using a wrench, otherwise the piezoelectric plates may come off from the prisms) and with a sharpened “ballerina” cutter with a minimum depth feed, level (smooth) the remains of the tread to flat state.

Protector blanks 20 × 22 mm in size are cut out of sheet plexiglass with a thickness of 3 mm, on which noise-absorbing teeth are applied on one side (size 20 mm) (0.8 mm pitch; angle 45 ° - 50 °, depth 0.8 mm), similar available on the prism.

On the one hand, the manufactured protectors are cleaned on fine sandpaper until a matte surface is obtained.

PET surfaces treated in this way (see above) and protectors are degreased with acetone or alcohol. Next, gluing is done.

Gluing the PEP to the protector is done either with a very liquid solution of “Acrylic Oxide” (dental filling material) powder-liquid ratio of approximately 5 - 10% powder - 95 - 90% liquid, or sold in stalls and household stores. stores with “Japanese” acrylate superglue. Gluing is done using a clamp. It is advisable to align the sound-absorbing teeth on the front edge of the protector with the same level as existing teeth on the prisms; remove excess glue (in a liquid state) from the teeth and from the side surfaces of the finder.

Drying approximately 10 minutes. Under a lamp with a power not exceeding 60 W (distance to the lamp - 10 cm). After gluing and drying, the PEP is installed on a milling machine (for the installation and clamping procedure, see above), and a ballerina makes a longitudinal selection of the required radius.

The depth of the sample, in its thin part (the center of the finder), is chosen such that the remainder of the prism from the edge of the body to the center of curvature of the machine being processed amounts to a total of 1.5 - 1.65 mm.

Accordingly, if the remainder of the prisms before trimming the probe body after cleaning was 0.1 ÷ 0.2 mm, the depth of the radius sampling is (with a tread thickness of 3 mm) - 1.6 ÷ 1.7 mm.

After making the curvature with a disk cutter 0.85 - 1.0 mm thick, a longitudinal cut is made in the middle of the resulting recess to insert an acoustic shield that is missing from the glued protector.

The cut should accordingly reach the remainder of the screen remaining on the probe when stripping the prism (cut depth 1.6 ÷ 1.7 mm) glued with “Japanese” superglue. The screen, 0.85 - 1.0 mm thick (according to the thickness of the cutter), is cut out of an oil-resistant cork-compound gasket from the Moskvich-407 car engine; 408 (Hatch gasket for cylinder block pushers).

After drying, the remainder of the screen is cut to the level of the new prism with a scalpel.

In the recess remaining near the sound-absorbing teeth, a mass of the following composition is applied as sound insulation: 3 parts of automotive polyester putty (any brand of kolomix, hempropol, etc.), 1 part - powder, plugs (by volume).

After drying, the excess soundproofing mass is cut off with a scalpel. Next, the tread is sanded with fine sandpaper to remove scratches after the “ballerina” and other roughness. If the described operations are followed, and the technician has the necessary qualifications, the converter after restoration according to RSHH is practically indistinguishable from a new one.

APPENDIX 2

PASSPORT
5.0 70° Æ 89 No. 1, 2 TsNIITMASH

Basic technical data:

f 0 , MHz 5 ± 10 %

f

f, MHz 4.6 ± 0.1

7.Calculated center value

Focal spot depth, mm 6.5

Note Æ

The converter meets the requirements for non-destructive testing means in accordance with GOST 26266-90, and is recognized as suitable for use.

PASSPORT
for ultrasonic inclined separate-combined general purpose transducer type PKN PC 5.0 70° Æ 114 No. 3, 4 TsNIITMASH

Basic technical data:

1. Rated operating frequencyf 0 , MHz 5 ± 10 %

* The deviation of the inverter operating frequency can reach up tof- over 5 MHz, large values, without deterioration of the RSH of the probe (GOST 26266-90)

2. Actual operating frequency valuef, MHz 4.6 ± 0.1

3. Input angle (for steel), degrees. 70°

4. Piezo plate size, mm 2×5×5

5. Converter boom, mm 6 ± 0.5

6. Echo pulse duration, μs 1.2 ± 0.1

7.Calculated center value

focal spot depth, mm 6.5

8. Range of sound thicknesses, mm 2 - 10

9. Operating temperature range, degrees. C -10 ÷ +30

10. Overall dimensions of the converter, mm 20×22×19

Note: the echo pulse duration is measured using the standard CO-2 standard according to GOST 14762-76 at a level of 12 dB from the maximum, from cylindrical drilling Æ 6 mm from the near side, with the UD2-12 device. Measurements are taken before the tread curvature is manufactured.

PASSPORT
for ultrasonic inclined separate-combined general purpose transducer type PKN PC 5.0 70° Æ 159 No. 5, 6 TsNIITMASH

Basic technical data:

1. Rated operating frequencyf 0 , MHz 5 ± 10 %

* The deviation of the inverter operating frequency can reach up tof- over 5 MHz, large values, without deterioration of the RSH of the probe (GOST 26266-90)

2. Actual operating frequency valuef, MHz 4.6 ± 0.1

3. Input angle (for steel), degrees. 70°

4. Piezo plate size, mm 2×5×5

5. Converter boom, mm 6 ± 0.5

6. Echo pulse duration, μs 1.2 ± 0.1

7. Calculated value of focal center

spots in depth, mm 6.5

8. Range of sound thicknesses, mm 2 - 10

9. Operating temperature range, degrees. C -10 ÷ +30

10. Overall dimensions of the converter, mm 20×22×19

Note: measurement of the echo pulse duration is carried out using the standard CO-2 standard according to GOST 14762-76 at a level of 12 dB from the maximum, from cylindrical drilling Æ 6 mm from the near side, with the UD2-12 device. Measurements are taken before the tread curvature is manufactured.

The converter meets the requirements for non-destructive testing means in accordance with GOST 26266-90, and is recognized as suitable for use.

GOST R 55724-2013

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

NON-DESTRUCTIVE CONTROL. WELDED CONNECTIONS

Ultrasonic methods

Non-destructive testing. Welded joints. Ultrasonic methods

Date of introduction 2015-07-01

Preface

Preface

1 DEVELOPED by the Federal State Enterprise "Research Institute of Bridges and Flaw Detection of the Federal Agency of Railway Transport" (Research Institute of Bridges), the State Scientific Center of the Russian Federation "Open Joint Stock Company" Research and Production Association "Central Research Institute of Mechanical Engineering Technology" (JSC NPO "TsNIITMASH" "), Federal State Autonomous Institution "Research and Training Center "Welding and Control" at Moscow State Technical University named after N.E. Bauman"

2 INTRODUCED by the Technical Committee for Standardization TC 371 “Non-Destructive Testing”

3 APPROVED AND PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated November 8, 2013 N 1410-st

4 INTRODUCED FOR THE FIRST TIME

5 REPUBLICATION. April 2019


The rules for the application of this standard are established in Article 26 of the Federal Law of June 29, 2015 N 162-FZ "On standardization in the Russian Federation" . Information about changes to this standard is published in the annual (as of January 1 of the current year) information index "National Standards", and the official text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the next issue of the monthly information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (www.gost.ru)

1 area of ​​use

This standard establishes methods for ultrasonic testing of butt, fillet, lap and tee joints with full root penetration, made by arc, electroslag, gas, gas pressure, electron beam, laser and flash butt welding or their combinations, in welded products made of metals and alloys for detection of the following discontinuities: cracks, lack of penetration, pores, non-metallic and metallic inclusions.

This standard does not regulate methods for determining the actual size, type and shape of the identified discontinuities (defects) and does not apply to the control of anti-corrosion surfacing.

The need for and scope of ultrasonic testing, types and sizes of discontinuities (defects) to be detected are established in the standards or design documentation for products.

2 Normative references

This standard uses normative references to the following standards:

GOST 12.1.001 System of occupational safety standards. Ultrasound. General safety requirements

GOST 12.1.003 System of occupational safety standards. Noise. General safety requirements

GOST 12.1.004 System of occupational safety standards. Fire safety. General requirements

GOST 12.2.003 System of occupational safety standards. Production equipment. General safety requirements

GOST 12.3.002 System of occupational safety standards. Production processes. General safety requirements

GOST 2789 Surface roughness. Parameters and characteristics

GOST 18353 * Non-destructive testing. Classification of types and methods
________________
* No longer valid. GOST R 56542-2015 is valid.


GOST 18576-96 Non-destructive testing. Railway rails. Ultrasonic methods

GOST R 55725 Non-destructive testing. Ultrasonic piezoelectric transducers. General technical requirements

GOST R 55808 Non-destructive testing. Ultrasonic transducers. Test methods

Note - When using this standard, it is advisable to check the validity of reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current year, and on issues of the monthly information index "National Standards" for the current year. If an undated reference standard is replaced, it is recommended that the current version of that standard be used, taking into account any changes made to that version. If a dated reference standard is replaced, it is recommended to use the version of that standard with the year of approval (adoption) indicated above. If, after the approval of this standard, a change is made to the referenced standard to which a dated reference is made that affects the provision referred to, it is recommended that that provision be applied without regard to that change. If the reference standard is canceled without replacement, then the provision in which a reference to it is given is recommended to be applied in the part that does not affect this reference.

3 Terms and definitions

3.1 The following terms with corresponding definitions are used in this standard:

3.1.19 SKH diagram: Graphic representation of the dependence of the detection coefficient on the depth of the flat-bottomed artificial reflector, taking into account its size and type of transducer.

3.1.20 rejection sensitivity level: The level of sensitivity at which a decision is made to classify an identified discontinuity as a “defect”.

3.1.21 diffraction method: A method of ultrasonic testing using the reflection method, using separate transmitting and receiving transducers and based on receiving and analyzing the amplitude and/or time characteristics of wave signals diffracted by a discontinuity.

3.1.22 reference sensitivity level (fixation level): The level of sensitivity at which discontinuities are recorded and their acceptability is assessed based on their conventional size and quantity.

3.1.23 reference signal: A signal from an artificial or natural reflector in a sample of a material with specified properties or a signal that has passed through a controlled product, which is used in determining and adjusting the reference level of sensitivity and/or measured discontinuity characteristics.

3.1.24 reference sensitivity level: The sensitivity level at which the reference signal has a specified height on the flaw detector screen.

3.1.25 depth gauge error: The error in measuring the known distance to the reflector.

3.1.26 search sensitivity level: The level of sensitivity set when searching for discontinuities.

3.1.27 maximum sensitivity of control using the echo method: Sensitivity, characterized by the minimum equivalent area (in mm) of the reflector that can still be detected at a given depth in the product for a given equipment setting.

3.1.28 entry angle: The angle between the normal to the surface on which the transducer is installed and the line connecting the center of the cylindrical reflector to the beam exit point when the transducer is installed in the position at which the amplitude of the echo signal from the reflector is greatest.

3.1.29 conditional size (length, width, height) of the defect: The size in millimeters corresponding to the zone between the extreme positions of the transducer, within which the signal from a discontinuity is recorded at a given sensitivity level.

3.1.30 conventional distance between discontinuities: The minimum distance between transducer positions at which the amplitudes of echo signals from discontinuities are fixed at a given sensitivity level.

3.1.31 conditional sensitivity of control using the echo method: Sensitivity, which is determined by the CO-2 (or CO-3P) measure and is expressed by the difference in decibels between the reading of the attenuator (calibrated amplifier) ​​at a given flaw detector setting and the reading corresponding to the maximum attenuation (gain) at which a cylindrical hole with a diameter of 6 mm at a depth 44 mm is fixed by flaw detector indicators.

3.1.32 scan step: The distance between adjacent trajectories of movement of the transducer beam exit point on the surface of the controlled object.

3.1.33 equivalent discontinuity area: The area of ​​a flat-bottomed artificial reflector oriented perpendicular to the acoustic axis of the transducer and located at the same distance from the input surface as the discontinuity, at which the signal values ​​of the acoustic device from the discontinuity and the reflector are equal.

3.1.34 equivalent sensitivity: Sensitivity, expressed by the difference in decibels between the gain value at a given flaw detector setting and the gain value at which the amplitude of the echo signal from the reference reflector reaches a specified value along the y-axis of the Type A scan.

4 Symbols and abbreviations

4.1 The following symbols are used in this standard:

I - emitter;

P - receiver;

Conditional height of the defect;

Conditional length of the defect;

Conditional distance between defects;

Conditional defect width;

Sensitivity is extreme;

Transverse scanning step;

Longitudinal scanning step.

4.2 The following abbreviations are used in this standard:

BCO - side cylindrical hole;

BUT - tuning sample;

PET - piezoelectric transducer;

Ultrasound - ultrasound (ultrasonic);

UZK - ultrasonic testing;

EMAT - electromagnetoacoustic transducer.

5 General provisions

5.1 When ultrasonic testing of welded joints, methods of reflected radiation and transmitted radiation are used in accordance with GOST 18353, as well as their combinations, implemented by methods (variants of methods), sounding schemes regulated by this standard.

5.2 When ultrasonic testing of welded joints, the following types of ultrasonic waves are used: longitudinal, transverse, surface, longitudinal subsurface (head).

5.3 For ultrasonic inspection of welded joints, the following inspection means are used:

- Ultrasonic pulse flaw detector or hardware-software complex (hereinafter referred to as flaw detector);

- converters (PEP, EMAP) in accordance with GOST R 55725 or non-standardized converters (including multi-element ones), certified (calibrated) taking into account the requirements of GOST R 55725;

- measures and/or BUT for setting up and checking flaw detector parameters.

Additionally, auxiliary devices and devices can be used to maintain scanning parameters, measure the characteristics of identified defects, evaluate roughness, etc.

5.4 Flaw detectors with transducers, measures, NO, auxiliary devices and devices used for ultrasonic testing of welded joints must provide the ability to implement ultrasonic testing methods and techniques from those contained in this standard.

5.5 Measuring instruments (flaw detectors with transducers, measures, etc.) used for ultrasonic testing of welded joints are subject to metrological support (control) in accordance with the current legislation.

5.6 Technological documentation for ultrasonic testing of welded joints should regulate: types of tested welded joints and requirements for their testability; requirements for the qualifications of personnel performing ultrasonic testing and quality assessment; the need for ultrasonic testing of the near-weld zone, its dimensions, control methods and quality requirements; control zones, types and characteristics of defects to be detected; methods of control, types of means and auxiliary equipment used for control; values ​​of the main control parameters and methods for setting them; sequence of operations; ways to interpret and record results; criteria for assessing the quality of objects based on ultrasonic inspection results.

6 Control methods, sounding schemes and methods for scanning welded joints

6.1 Control methods

In ultrasonic testing of welded joints, the following methods (variants of methods) of control are used: echo-pulse, mirror-shadow, echo-shadow, echo-mirror, diffraction, delta (Figures 1-6).

It is allowed to use other methods of ultrasonic testing of welded joints, the reliability of which is confirmed theoretically and experimentally.

Ultrasound testing methods are implemented using converters connected in combined or separate circuits.

Figure 1 - Pulse echo

Figure 2 - Mirror-Shadow

Figure 3 - Echo-shadow direct (a) and inclined (b) probe

Figure 4 - Echo-mirror

Figure 5 - Diffraction

Figure 6 - Variants of the delta method

6.2 Sounding schemes for various types of welded joints

6.2.1 Ultrasonic testing of butt welded joints is performed with straight and inclined transducers using sounding schemes with direct, single-reflected, double-reflected beams (Figures 7-9).

It is allowed to use other sounding schemes given in the technological documentation for control.

Figure 7 - Scheme of sounding a butt welded joint with a direct beam

Figure 8 - Scheme of sounding a butt welded joint with a single-reflected beam

Figure 9 - Scheme of sounding a butt welded joint with a doubly reflected beam

6.2.2 Ultrasonic testing of T-weld joints is performed with direct and inclined transducers using direct and (or) single-reflected beam sounding schemes (Figures 10-12).

Note - In the figures, the symbol indicates the direction of sounding by the inclined probe “from the observer”. With these schemes, sounding is performed in the same way in the direction “towards the observer”.

Figure 10 - Schemes for sounding a T-weld joint with direct (a) and single-reflected (b) beams

Figure 11 - Schemes for sounding a T-weld joint with a direct beam

Figure 12 - Scheme of sounding a T-weld joint with inclined transducers according to a separate scheme (H-lack of penetration)

6.2.3 Ultrasonic testing of corner welded joints is performed with straight and inclined transducers using direct and (or) single-reflected beam sounding schemes (Figures 13-15).

It is allowed to use other schemes given in the technological control documentation.

Figure 13 - Scheme of sounding a fillet welded joint using combined inclined and direct transducers

Figure 14 - Scheme of sounding a fillet welded joint with double-sided access using combined inclined and direct transducers, subsurface (head) wave transducers

Figure 15 - Scheme of sounding a fillet welded joint with one-sided access using combined inclined and direct transducers, subsurface (head) wave transducers

6.2.4 Ultrasonic inspection of lap welded joints is performed with inclined transducers using the sounding circuits shown in Figure 16.

Figure 16 - Scheme for sounding a lap welded joint using combined (a) or separate (b) schemes

6.2.5 Ultrasonic inspection of welded joints in order to detect transverse cracks (including in joints with a removed weld bead) is performed with inclined transducers using the sounding circuits shown in Figures 13, 14, 17.

Figure 17 - Scheme of sounding butt welded joints during inspection to search for transverse cracks: a) - with the weld bead removed; b) - with the seam bead not removed

6.2.6 Ultrasound examination of welded joints in order to detect discontinuities lying near the surface on which scanning is performed is performed by longitudinal subsurface (head) waves or surface waves (for example, Figures 14, 15).

6.2.7 Ultrasonic testing of butt welded joints at the intersections of the seams is performed by inclined transducers using the sounding schemes shown in Figure 18.

Figure 18 - Schemes for sounding the intersections of butt welded joints

6.3 Scanning methods

6.3.1 Scanning of a welded joint is carried out according to the method of longitudinal and (or) transverse movement of the transducer at constant or varying angles of input and turn of the beam. The method of scanning, the direction of sounding, the surfaces from which sounding is carried out, must be established taking into account the purpose and testability of the connection in the technological documentation for testing.

6.3.2 When ultrasonic testing of welded joints, transverse-longitudinal (Figure 19) or longitudinal-transverse (Figure 20) scanning methods are used. It is also allowed to use the sweeping beam scanning method (Figure 21).

Figure 19 - Variants of the method of transverse-longitudinal scanning

Figure 20 - The method of transverse-longitudinal scanning

Figure 21 - Sweeping beam scanning method

7 Requirements for controls

7.1 Flaw detectors used for ultrasonic testing of welded joints must provide adjustment of the gain (attenuation) of signal amplitudes, measurement of the ratio of signal amplitudes throughout the entire range of gain (attenuation) adjustment, measurement of the distance traveled by the ultrasonic pulse in the test object to the reflecting surface, and the coordinates of the location of the reflecting surface relative to the exit point of the beam.

7.2 Transducers used in conjunction with flaw detectors for ultrasonic testing of welded joints must provide:

- deviation of the operating frequency of ultrasonic oscillations emitted by the transducers from the nominal value - no more than 20% (for frequencies no more than 1.25 MHz), no more than 10% (for frequencies above 1.25 MHz);

- deviation of the beam input angle from the nominal value - no more than ±2°;

- deviation of the beam exit point from the position of the corresponding mark on the transducer is no more than ±1 mm.

The shape and dimensions of the transducer, the values ​​of the inclined transducer boom and the average ultrasonic path in the prism (protector) must comply with the requirements of the technological documentation for control.

7.3 Measures and settings

7.3.1 When ultrasonic testing of welded joints, measures and/or ND are used, the scope of application and verification (calibration) conditions of which are specified in the technological documentation for ultrasonic testing.

7.3.2 Measures (calibration samples) used for ultrasonic testing of welded joints must have metrological characteristics that ensure repeatability and reproducibility of measurements of echo signal amplitudes and time intervals between echo signals, according to which the basic parameters of ultrasonic testing, regulated by technological documentation, are adjusted and checked at the ultrasound.

As measures for setting up and checking the basic parameters of ultrasonic testing with transducers with a flat working surface at a frequency of 1.25 MHz and more, you can use samples SO-2, SO-3, or SO-3R in accordance with GOST 18576, the requirements for which are given in Appendix A.

7.3.3 NO used for ultrasonic testing of welded joints must provide the ability to configure time intervals and sensitivity values ​​specified in the technological documentation for ultrasonic testing, and have a passport containing the values ​​of geometric parameters and ratios of the amplitudes of echo signals from reflectors in the NO and measures, and also identification data of the measures used in the certification.

As a reference for setting up and checking the basic parameters of ultrasonic testing, samples with flat-bottomed reflectors, as well as samples with BCO, segment or corner reflectors are used.

It is also allowed to use calibration samples V1 according to ISO 2400:2012, V2 according to ISO 7963:2006 (Appendix B) or their modifications, as well as samples made from test objects with structural reflectors or alternative reflectors of arbitrary shape, as ND.

8 Preparation for control

8.1 The welded joint is prepared for ultrasonic inspection if there are no external defects in the joint. The shape and dimensions of the heat-affected zone must allow the transducer to be moved within the limits determined by the degree of testability of the connection (Appendix B).

8.2 The surface of the connection on which the converter is moved must not have dents or irregularities; splashes of metal, flaking scale and paint, and dirt must be removed from the surface.

When machining a joint as provided for in the technological process for manufacturing a welded structure, the surface roughness must be no worse than 40 microns according to GOST 2789.

Requirements for surface preparation, permissible roughness and waviness, methods for measuring them (if necessary), as well as the presence of non-flaking scale, paint and surface contamination of the test object are indicated in the technological documentation for control.

8.3 Non-destructive testing of the heat-affected zone of the base metal for the absence of delaminations that impede ultrasonic testing with an inclined transducer is carried out in accordance with the requirements of the technological documentation.

8.4 The welded joint should be marked and divided into sections so as to unambiguously determine the location of the defect along the length of the seam.

8.5 Pipes and tanks must be free of liquid before testing with a reflected beam.

It is allowed to control pipes, tanks, ship hulls with liquid under the bottom surface according to the methods regulated by the technological documentation for control.

8.6 Basic control parameters:

a) frequency of ultrasonic vibrations;

b) sensitivity;

c) position of the beam exit point (boom) of the transducer;

d) angle of beam entry into the metal;

e) coordinate measurement error or depth gauge error;

e) dead zone;

g) resolution;

i) the opening angle of the radiation pattern in the plane of wave incidence;

j) scanning step.

8.7 The frequency of ultrasonic vibrations should be measured as the effective frequency of the echo pulse according to GOST R 55808.

8.8 The main parameters according to b)-i) 8.6 should be adjusted (checked) according to measures or NO.

8.8.1 Conditional sensitivity for echo-pulse ultrasonic testing should be adjusted according to CO-2 or CO-3R measures in decibels.

The conditional sensitivity for mirror-shadow ultrasonic testing should be adjusted on a defect-free section of the welded joint or on the NO in accordance with GOST 18576.

8.8.2 The maximum sensitivity for echo-pulse ultrasonic testing should be adjusted according to the area of ​​the flat-bottomed reflector in the NO or according to the ARD, SKH - diagrams.

It is allowed, instead of a non-reflective device with a flat-bottomed reflector, to use a non-reflective device with segmental, corner reflectors, BCO or other reflectors. The method for setting the maximum sensitivity for such samples should be regulated in the technological documentation for ultrasonic testing. At the same time, for NO with a segment reflector

where is the area of ​​the segment reflector;

and for NO with a corner reflector

where is the area of ​​the corner reflector;

- coefficient, the values ​​of which for steel, aluminum and its alloys, titanium and its alloys are shown in Figure 22.

When using ARD and SKH diagrams, echo signals from reflectors in measures CO-2, CO-3, as well as from the bottom surface or dihedral angle in the controlled product or in the NO are used as a reference signal.

Figure 22 - Graph for determining the correction to the maximum sensitivity when using a corner reflector

8.8.3 Equivalent sensitivity for echo-pulse ultrasonic testing should be adjusted using NO, taking into account the requirements of 7.3.3.

8.8.4 When adjusting the sensitivity, a correction should be introduced that takes into account the difference in the state of the surfaces of the measure or reference and the controlled connection (roughness, presence of coatings, curvature). Methods for determining corrections must be indicated in the technological documentation for control.

8.8.5 The beam entry angle should be measured according to measures or BUT at an ambient temperature corresponding to the control temperature.

The angle of beam entry when testing welded joints with a thickness of more than 100 mm is determined in accordance with the technological documentation for testing.

8.8.6 The coordinate measurement error or the depth gauge error, the dead zone, the opening angle of the radiation pattern in the plane of wave incidence should be measured using SO-2, SO-3R or HO measures.

9 Carrying out control

9.1 Sounding of a welded joint is performed according to the diagrams and methods given in Section 6.

9.2 Acoustic contact of the probe with the controlled metal should be created by contact, or immersion, or slot methods of introducing ultrasonic vibrations.

9.3 Scanning steps are determined taking into account the specified excess of the search sensitivity level over the control sensitivity level, the directional pattern of the transducer and the thickness of the controlled welded joint, while the scanning step should be no more than half the size of the active element of the probe in the direction of the step.

9.4 When carrying out ultrasonic testing, the following sensitivity levels are used: reference level; reference level; rejection level; search level.

The quantitative difference between sensitivity levels must be regulated by technological documentation for control.

9.5 The scanning speed during manual ultrasonic testing should not exceed 150 mm/s.

9.6 To detect defects located at the ends of the connection, you should additionally sound the zone at each end, gradually turning the transducer towards the end at an angle of up to 45°.

9.7 When ultrasonic inspection of welded joints of products with a diameter of less than 800 mm, the control zone should be adjusted using artificial reflectors made in NO, having the same thickness and radius of curvature as the product being tested. The permissible deviation along the radius of the sample is no more than 10% of the nominal value. When scanning along an external or internal surface with a radius of curvature of less than 400 mm, the prisms of the inclined probes must correspond to the surface (be ground in). When monitoring RS probes and direct probes, special attachments should be used to ensure constant orientation of the probe perpendicular to the scanning surface.

Processing (grinding) of the probe must be carried out in a device that prevents the probe from being skewed relative to the normal to the input surface.

Features of setting the main parameters and monitoring cylindrical products are indicated in the technological documentation for ultrasonic testing.

9.8 The scanning stage during mechanized or automated ultrasonic testing using special scanning devices should be performed taking into account the recommendations of the equipment operating manuals.

10 Measurement of defect characteristics and quality assessment

10.1 The main measured characteristics of the identified discontinuity are:

- the ratio of the amplitude and/or time characteristics of the received signal and the corresponding characteristics of the reference signal;

- equivalent discontinuity area;

- coordinates of discontinuity in the welded joint;

- conventional dimensions of discontinuity;

- conventional distance between discontinuities;

- the number of discontinuities at a certain length of the connection.

The measured characteristics used to assess the quality of specific compounds must be regulated by technological control documentation.

10.2 The equivalent area is determined by the maximum amplitude of the echo signal from the discontinuity by comparing it with the amplitude of the echo signal from the reflector in the NO or by using calculated diagrams, provided that their convergence with experimental data is at least 20%.

10.3 The following can be used as conditional dimensions of the identified discontinuity: conditional length; conditional width ; conditional height (Figure 23).

The conditional length is measured by the length of the zone between the extreme positions of the transducer, moved along the seam and oriented perpendicular to the axis of the seam.

The conventional width is measured by the length of the zone between the extreme positions of the transducer moved in the plane of incidence of the beam.

The conditional height is determined as the difference in the measured values ​​of the depth of the discontinuity in the extreme positions of the transducer moved in the plane of incidence of the beam.

10.4 When measuring conventional dimensions , , the extreme positions of the transducer are taken to be those at which the amplitude of the echo signal from the detected discontinuity is either 0.5 of the maximum value (relative measurement level - 0.5), or corresponds to a given sensitivity level.

It is allowed to measure the conventional sizes of discontinuities at values ​​of the relative measurement level from 0.8 to 0.1, if this is indicated in the technological documentation for the ultrasonic testing.

The conditional width and conditional height of an extended discontinuity are measured in the section of the connection where the echo signal from the discontinuity has the greatest amplitude, as well as in sections located at distances specified in the technological documentation for control.

Figure 23 - Measurement of conventional sizes of defects

10.5 The conventional distance between discontinuities is measured by the distance between the extreme positions of the transducer. In this case, the extreme positions are set depending on the length of the discontinuities:

- for a compact discontinuity (, where is the conditional length of a non-directional reflector located at the same depth as the discontinuity), the position of the transducer at which the amplitude of the echo signal is maximum is taken as the extreme position;

- for an extended discontinuity (), the position of the transducer at which the amplitude of the echo signal corresponds to the specified level of sensitivity is taken as the extreme position.

10.6 Welded joints in which the measured value of at least one characteristic of the identified defect is greater than the rejection value of this characteristic specified in the technological documentation do not meet the requirements of ultrasonic inspection.

11 Registration of control results

11.1 The results of the ultrasonic inspection must be reflected in the working, accounting and acceptance documentation, the list and forms of which are accepted in the prescribed manner. The documentation must contain information:

- about the type of joint being monitored, the indices assigned to the product and the welded joint, the location and length of the section subject to ultrasonic testing;

- technological documentation in accordance with which ultrasonic testing is performed and its results are evaluated;

- date of control;

- identification data of the flaw detector;

- type and serial number of the flaw detector, converters, measures, NO;

- uncontrolled or incompletely controlled areas subject to ultrasonic testing;

- results of ultrasonic testing.

11.2 Additional information to be recorded, the procedure for preparing and storing the journal (conclusions, as well as the form for presenting control results to the customer) must be regulated by the technological documentation for the ultrasonic testing facility.

11.3 The need for an abbreviated recording of inspection results, the designations used and the order of their recording must be regulated by the technological documentation for ultrasonic testing. For abbreviated notation, the notation according to Appendix D may be used.

12 Safety requirements

12.1 When carrying out work on ultrasonic testing of products, the flaw detector must be guided by GOST 12.1.001, GOST 12.2.003, GOST 12.3.002, rules for the technical operation of consumer electrical installations and technical safety rules for the operation of consumer electrical installations, approved by Rostechnadzor.

12.2 When performing monitoring, the requirements and safety requirements set out in the technical documentation for the equipment used, approved in the prescribed manner, must be observed.

12.3 The noise levels generated at the flaw detector’s workplace must not exceed those permitted by GOST 12.1.003.

12.4 When organizing control work, fire safety requirements in accordance with GOST 12.1.004 must be observed.

Appendix A (mandatory). Measures SO-2, SO-3, SO-3R for checking (adjusting) the basic parameters of ultrasonic testing

Appendix A
(required)

A.1 Measures SO-2 (Figure A.1), SO-3 (Figure A.2), SO-3R according to GOST 18576 (Figure A.3) should be made of grade 20 steel and used for measurement (adjustment) and checking the basic parameters of equipment and monitoring with converters with a flat working surface at a frequency of 1.25 MHz and more.

Figure A.1 - Sketch of CO-2 measure

Figure A.2 - Sketch of measure CO-3

Figure A.3 - Sketch of measure SO-3R

A.2 The CO-2 measure should be used to adjust the conditional sensitivity, as well as to check the dead zone, depth gauge error, beam entry angle, opening angle of the main lobe of the radiation pattern in the plane of incidence and determining the maximum sensitivity when inspecting steel joints.

A.3 When testing connections made of metals that differ in acoustic characteristics from carbon and low-alloy steels (in terms of longitudinal wave propagation speed by more than 5%) to determine the beam entry angle, the opening angle of the main lobe of the radiation pattern, the dead zone, as well as the maximum sensitivity NO SO-2A, made of controlled material, must be used.

A.4 The CO-3 measure should be used to determine the exit point of the transducer beam and boom.

A.5 Measure СО-3Р should be used to determine and configure the main parameters listed in 8.8 for measures СО-2 and СО-3.

Appendix B (for reference). Adjustment samples for checking (adjusting) the main parameters of ultrasonic testing

Appendix B
(informative)

B.1 NO with a flat-bottomed reflector is a metal block made of a controlled material, in which a flat-bottomed reflector is made, oriented perpendicular to the acoustic axis of the transducer. The depth of the flat-bottomed reflector must comply with the requirements of the technological documentation.

1 - bottom of the hole; 2 - converter; 3 - block made of controlled metal; 4 - acoustic axis

Figure B.1 - Sketch of a NO with a flat-bottomed reflector

B.2 HO V1 according to ISO 2400:2012 is a metal block (Figure B.1) made of carbon steel into which a 50 mm diameter cylinder made of plexiglass is pressed.

HO V1 is used to adjust the scanning parameters of the flaw detector and depth gauge, adjust sensitivity levels, as well as evaluate the dead zone, resolution, determine the exit point of the beam, the boom and the angle of entry of the transducer.

B.3 HO V2 according to ISO 7963:2006 is made of carbon steel (Figure B.2) and is used to adjust the depth gauge, adjust sensitivity levels, determine the beam exit point, boom and transducer entry angle.

Figure B.2 - Sketch of NO V1

Figure B.3 - Sketch of NO V2

Appendix B (recommended). Degrees of testability of welded joints

For seams of welded joints, the following degrees of testability are established in descending order:

1 - the acoustic axis intersects each element (point) of the controlled section from at least two directions, depending on the requirements of the technological documentation;

2 - the acoustic axis intersects each element (point) of the controlled section from one direction;

3 - there are elements of a controlled cross-section, which, with a regulated sound pattern, the acoustic axis of the directional pattern does not intersect in any direction. In this case, the area of ​​non-sounding areas does not exceed 20% of the total area of ​​the controlled section and they are located only in the subsurface part of the welded joint.

Directions are considered different if the angle between the acoustic axes is at least 15°.

Any degree of testability, except 1, is established in the technological documentation for control.

In an abbreviated description of the control results, each defect or group of defects should be indicated separately and designated by a letter:

- a letter that determines the qualitative assessment of the admissibility of a defect based on the equivalent area (amplitude of the echo signal - A or D) and conditional length (B);

- a letter that qualitatively determines the conditional length of the defect, if it is measured in accordance with 10.3 (D or F);

- a letter that defines the configuration (volumetric - W, planar - P) of the defect, if it is installed;

- a figure that determines the equivalent area of ​​the detected defect, mm, if it was measured;

- a number defining the greatest depth of the defect, mm;

- a number defining the conditional length of the defect, mm;

- a number defining the conditional width of the defect, mm;

- a number defining the conditional height of the defect, mm or µs*.
________________
* The text of the document corresponds to the original. - Database manufacturer's note.


For abbreviated notation the following notations should be used:

A - a defect, the equivalent area (amplitude of the echo signal) and the conditional length of which are equal to or less than the allowable values;

D - defect, the equivalent area (amplitude of the echo signal) which exceeds the allowable value;

B - defect, the conditional length of which exceeds the permissible value;

G - defect, the conditional length of which is ;

E - defect, the nominal length of which is ;

B is a group of defects spaced apart from each other;

T - a defect that, when the transducer is located at an angle of less than 40 ° to the weld axis, causes the appearance of an echo signal exceeding the amplitude of the echo signal when the transducer is located perpendicular to the weld axis, by the value specified in the technical documentation for testing, approved in the prescribed manner.

The conditional length for defects of types G and T is not indicated.

In the abbreviated notation, numerical values ​​are separated from each other and from letter designations by a hyphen.

Bibliography

UDC 621.791.053:620.169.16:006.354
Key words: non-destructive testing, welded seams, ultrasonic methods

Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2019