In construction, pipes Ø from 28 to 1420 mm with a wall thickness of 3 to 30 mm are used. The entire range of diameters according to flaw detection can be conditionally divided into 3 groups:

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

According to studies that were carried out at the Moscow State Technical University. N.E. Bauman recently, in the process of developing methods for ultrasonic testing of welded pipe joints, one should take into account such a very important factor as the anisotropy of the elastic characteristics of the pipe material.

Anisotropy of pipe steel, its features

Anisotropy- this is the difference in the properties of the medium (for example, physical: thermal conductivity, elasticity, electrical conductivity, etc.) in different directions within this medium.

In the process of ultrasonic testing of welded joints of main gas pipelines, assembled from pipes of domestic and foreign production, the omission of serious root defects, an inaccurate assessment of their coordinates, and a significant level of acoustic noise were found.

It turned out that, subject to the optimal control parameters and during its implementation, the main reason for skipping a defect is the presence of a significant anisotropy of the elastic properties of the base material. It affects the speed, attenuation and deviation from the straightness of the ultrasonic beam.

During the sounding of metal, more than 200 pieces of pipes according to the scheme shown in fig. 1, it turned out that the root-mean-square deviation of the wave velocity for such a direction of motion and polarization is 2 m/s (for transverse waves). Deviations of velocities from tabular values ​​by 100 m/s and more are not random and are probably related to the technology for the production of rolled products and pipes. Such deviations have a strong influence on the propagation of polarized waves. In addition to the indicated anisotropy, the inhomogeneity of the speed of sound over the thickness of the pipe wall was also found.

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

The structure of rolled sheets is layered, which is metal fibers and other inclusions elongated during deformation. In addition, due to the effect of the thermomechanical rolling cycle on the metal, sections of the sheet that are uneven in thickness are subjected to various deformations. These features become the reason that the speed of sound additionally depends on the depth of the sounded layer.

Features of control of welded seams of pipes of various diameters

Pipes Ø 28 to 100 mm

A distinctive feature of welded seams of pipes Ø from 28 to 100 mm with H from 3 to 7 mm is the occurrence of sagging inside the pipe. This causes false echo signals from them to appear on the screen of the flaw detector during inspection with a direct beam, which coincide in time with the echo signals reflected from root defects found by a single reflected beam. Due to the fact that the effective width of the beam is comparable to the thickness of the pipe wall, it is extremely difficult to identify the reflector by the location of the seeker relative to the amplification bead. There is also an uncontrolled zone in the center of the seam due to the large width of the seam bead. All this is the reason for the low probability (10-12%) of detecting unacceptable bulk defects, although unacceptable planar defects are detected much better (~ 85%). The main characteristics of sag - depth, width and angle of closure with the surface of the object - are random values ​​for this pipe size; the average values ​​are 2.7 mm, respectively; 6.5 mm and 56°30".

Rolled steel behaves like an anisotropic and inhomogeneous medium with rather complex dependences of elastic wave velocities on the direction of polarization and sounding. The speed of sound varies approximately symmetrically with respect to the middle of the sheet section, and in the region of this middle, the speed of the transverse wave can greatly (up to 10%) decrease in comparison with the surrounding regions. The speed of the transverse wave in controlled objects varies in the range from 3070 to 3420 m/s. At a depth of up to 3 mm from the rolled surface, the shear wave velocity may slightly (up to 1%) increase.

The noise immunity of the control is significantly increased in the case of using inclined separate-combined probes of the RSN type (Fig. 2), which are called chordal. They were designed at MSTU. N.E. Bauman. A feature of the control is that during the search for defects there is no need for transverse scanning. It is performed only along the perimeter of the pipe at the moment of pressing the front face of the transducer to the seam.

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

Pipes Ø 108 to 920 mm

Pipes Ø from 108 to 920 mm with H from 4 to 25 mm are also connected by one-sided welding without back welding. Until recently, the control of these joints was carried out using combined probes according to the method compiled for pipes Ø from 28 to 100 mm. But for such a control technique, a rather large zone of coincidences (a zone of uncertainty) is required. This significantly reduces the accuracy of the connection quality estimation. In addition, combined probes are characterized by a high level of reverberation noise, which makes it difficult to decipher signals, as well as uneven sensitivity, which cannot always be compensated by available means. The use of chordal separate-combined probes to control this size of welded joints is not advisable, because due to the limited angles of input of ultrasonic vibrations from the surface of the welded joint, the dimensions of the transducers increase significantly, and the acoustic contact area also becomes larger.

At MSTU im. N. E. Bauman created inclined probes with equalized sensitivity to perform inspection of welded joints Ø from 100 mm. Sensitivity equalization ensures such a choice of the turn angle 2 so that the upper part and the middle of the seam are sounded by the central once reflected beam, and the lower part - by direct peripheral beams that fall on the defect at an angle Y from the central one. On fig. Figure 3 shows a graph of the dependence of the angle of introduction of a transverse wave on the angle of turn and opening of the radiation pattern Y. In such probes, the incident and reflected waves from the defect are horizontally polarized (SH-wave).

Rice. 3. Changing the input angle alpha, within half of the opening angle of the RSN-SET beam pattern, depending on the turn angle delta.

It is clear from the graphs that during the inspection of objects with a wall thickness of 25 mm, the sensitivity unevenness of the RS-probe reaches 5 dB, while for a combined probe it can reach 25 dB. The RS-PEP is characterized by an increased signal-to-interference level and, therefore, by an increased absolute sensitivity. For example, the RS-probe can easily detect a defect with an area of ​​0.5 mm2 in the process of testing a welded joint 10 mm thick both with a direct and once reflected beam at a useful signal/noise ratio of 10 dB. The procedure for performing control with these probes is the same as with combined probes.

Pipes Ø from 1020 to 1420 mm

Welded joints of pipes Ø from 1020 to 1420 mm with H from 12 to 30 mm are performed by double-sided welding or with back welding of the seam. In seams that are made by double-sided welding, usually, false signals from the rear edge of the reinforcement bead do not interfere as much as in one-sided seams. Their amplitude is not so great due to the smoother outlines of the roller. In addition, they are further along the sweep. For this reason, this is the most suitable pipe size for flaw detection. But the results of studies conducted at MSTU. N. E. Bauman, show that the metal of these pipes is characterized by the greatest anisotropy. To reduce the effect of anisotropy on defect detection, a 2.5 MHz probe should be used with a prism angle of 45°, rather than 50° as specified in most regulations. The highest control accuracy was obtained using RSM-N12 probes. In contrast to the methodology compiled for pipes Ø from 28 to 100 mm, there is no zone of uncertainty in the control of these joints. Otherwise, the method of control is similar. When using a PC-probe, it is also recommended to set the sweep speed and sensitivity for vertical drilling. Adjustment of the sweep speed and sensitivity of inclined combined probes should be made using corner reflectors of the appropriate size.

When inspecting welds, it must be remembered that there are metal delaminations in the near-weld zone, which make it difficult to determine the coordinates of the defect. The zone in which a defect is found by an inclined probe must be additionally checked with a straight probe in order to clarify the nature of the defect and determine the exact value of the defect depth.

In the nuclear, petrochemical and nuclear power industries, clad steels are often used in the manufacture of pipelines, apparatus and vessels. For cladding the inner wall of these structures, austenitic steels are used, which are applied by surfacing, rolling or explosion with a layer of 5 to 15 mm.

The control process of these welded joints provides for the analysis of the continuity of the pearlite part of the weld, as well as the fusion zone with a restorative anticorrosion surfacing. In this case, the continuity of the body of the surfacing itself is not controlled.

But due to the difference in the acoustic characteristics of the base metal and austenitic steel, echo signals appear from the interface during ultrasonic testing, which prevent the detection of defects, for example, delamination of the cladding and undersurfacing cracks. In addition, the presence of cladding and its characteristics have a significant impact on the parameters of the acoustic path of the PET.

For this reason, standard technological solutions are ineffective in the control of thick-walled welds in clad pipelines.

After many years of research, scientists have found out the main features of the acoustic tract. Recommendations were received on optimizing its characteristics and a technology was developed for performing ultrasonic analysis of welds with austenitic cladding.

In particular, the scientists found that when the beam of ultrasonic waves is re-reflected from the boundary of the pearlite-austenitic cladding, the directivity diagram almost does not change in the case of rolling cladding and changes significantly in the case of surfacing cladding. Its width increases significantly, and within the main lobe there are oscillations of 15-20 dB, depending on the surfacing method. There is a significant displacement of the reflection exit point from the boundary of the beam cladding in comparison with its location, and the speed of transverse waves in the transition zone also changes.

When developing the technology for testing welded joints in clad pipelines, all this was taken into account. This technology provides for a preliminary obligatory determination of the thickness of the pearlite part (the penetration depth of the anti-corrosion surfacing).

For more accurate detection of planar defects (non-fusion and cracks), it is better to use a probe with an input angle of 45° and a frequency of 4 MHz. A more accurate detection of vertically oriented defects at an input angle of 45°, in contrast to the angles of 60 and 70°, is explained by the fact that during the sounding of the latter, the angle of encounter between the beam and the defect is close to the third critical one, at which the reflection coefficient of the transverse wave is minimal.
During the sounding of the pipe from the outside at a frequency of 2 MHz, the echo signals from defects are shielded by an intense and long-lasting noise signal. Immunity to PET interference at a frequency of 4 MHz is on average 12 dB higher. For this reason, a useful signal from a defect located in the immediate vicinity of the deposit boundary will be better read against the background of noise. And vice versa, during the sounding of the pipe from the inside through the surfacing, the best resistance to interference will be provided by the probe at a frequency of 2 MHz.

The document of Gosatomnadzor RFPNAEG-7-030-91 regulates the technology of control of welded seams of pipelines with surfacing.

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2(02), 2007/U9

The methods of the non destructive testing of pipes during manufacture are considered. It is shown, that the ultrasonic method provides revealing all types of defects peculiar to seamless pipes. The ways of pipes automated testing realization of are determined.

A. L. MAYOROV, Y. P. PROKHORENKO, State Scientific Institution "IPF NAH of Belarus"

ULTRASONIC TESTING OF SEAMLESS PIPES UNDER PRODUCTION CONDITIONS

Production defects of pipes are determined by the technology of their manufacture. Several technologies have become the most widely used. First of all, this is the production of electric-welded pipes. In this case, the focus is on the longitudinal weld and defects in the sheet from which the pipe is formed. Hot- and cold-deformed seamless pipes are primarily characterized by defects of metallurgical origin, formed in the workpiece from which the pipe is made. In addition, additional defects may occur, associated, for example, with insufficient or uneven heating during rolling or broaching. Cast iron pipes obtained by centrifugal casting stand apart. In any case, under production conditions, it is possible to carry out 100% automated control of pipes. The consumer of pipes has, as a rule, the possibility of selective inspection in manual and mechanized mode to check the pipes in the state of delivery. The method of control is the same in both cases. When examining pipes during operation, additional defects occur due to corrosion damage and defects in transverse welds. To identify them, other methods and primary converters are used.

Let us consider the main approaches to the development of means for non-destructive testing of seamless pipes in the conditions of their production. Conditionally, for the purposes of control, pipes can be divided into especially thick-walled pipes if their wall thickness 5 is more than 10% of the diameter D: 5>0.1D thick-walled pipes with wall thickness L-(0.025 - 0.05) 0 and especially thin-walled with a wall thickness of 5<0,025П.

Magnetic inspection methods can be used to control surface defects

defects or defects in thin-walled pipes made of magnetic materials. Eddy current testing can also be applied to surface defects or particularly thin-walled pipes. In addition, in these cases, defects can be detected by visual methods. When testing pipes with thick walls, ultrasonic methods are of the greatest interest. With their help, it is possible to determine defects both on the inner and outer surfaces, and inside the pipe wall.

From the standpoint of ultrasonic testing, it is necessary to distinguish between pipes of large diameter, i.e. diameter at which it is impossible to carry out control over the entire circumference of the pipe with one installation of the transducer. This is a diameter of approximately 400 mm. This is followed by pipes with a diameter of approximately 20 to 400 mm. In this case, it is possible to confidently receive an impulse that runs around the entire perimeter of the pipe. When testing pipes with a diameter of less than 20 mm, i.e. with an outer perimeter of less than 60-65 mm, the beam control becomes more effective, which propagates along the pipe in a spiral. In this case, it becomes possible to simultaneously control transverse defects (of course, in cases where their appearance is technologically possible, for example, in centrifugal casting). Moreover, the waves can be excited at several angles at the same time, which increases the reliability of testing and allows you to detect defects with deviations from the longitudinal or transverse orientation.

So, in our opinion, control in the production of seamless pipes should be started at the stage of billet manufacturing. As a rule, internal defects are defects that arose during casting. Then, after rolling or drawing, they take the form of longitudinal bundles. Internal defects can also occur due to insufficient heating of the billet before rolling. In any case, these defects have an axial orientation.

I 2 (42). 2007-

tation and can be detected by sounding in a direction perpendicular to the axis. In addition, tears and delaminations may appear on the surface. They are oriented at small angles to the axis, so they can also be detected during transverse sounding.

The control scheme and the number of transducers are determined by the workpiece diameter. On fig. 1 shows a diagram for detecting internal defects in a workpiece. The usual, traditional method is to use direct probes 2. To avoid rotation of the workpiece, several probes can be placed at 90° angles and opposite each other. Direct transducers in echo mode provide high sensitivity testing, providing detection of defects with an opening of units of square millimeters. Considering that there are no defects in the form of pores in the rolled billet, this sensitivity is sufficient. It should be taken into account that at the liquid-workpiece interface (in the immersion control version) the acoustic beam is defocused. Therefore, by choosing the size of the emitter, it is always possible to ensure control of a certain area of ​​the workpiece. At workpiece diameters less than -25 mm, control by a direct transducer in the immersion version becomes ineffective. This is due to the fact that part of the useful signal is masked due to the transformation at the interface. In this case, it is convenient to use a dual converter (3 in Fig. 1). The boundary between the emitters should be oriented parallel to the axis of the workpiece. Defects are revealed in the region of intersection of the radiation patterns (region 5 in Fig. 1). The circuit with a separate-combined transducer effectively works up to diameters of -200 mm. In the case of direct and dual-coupled transducers, it is possible to monitor the acoustic contact, for example, by the bottom signal. The pulse repetition rate is determined by the speed of the workpiece, depending on the width of the transducer radiation pattern and the required control sensitivity.

Defects that appear near the surface can be detected by means of oblique input of acoustic vibrations with the conversion of longitudinal waves into transverse ones, i.e. at angles between the first and second critical. The control scheme is shown in fig. 2. Usually, reflections from even small defects on the surface during the propagation of a surface wave significantly exceed the echo signals from internal defects for shear waves. In the case of immersion control, the emerging surface wave quickly decays due to the emission of part of the energy into the immersion medium. Entry angle

/\ I > - - - \

I ............... . ^

Rice. 1. Scheme of ultrasonic testing of internal defects of a cylindrical billet: I - controlled product; 2 - direct converter; 3 - separate-combined converter; 4 - area of ​​control by direct transducer; 5 - area of ​​control by a separate-combined transducer

a is determined by the technical requirements for the controlled product. The closer the angle is to the second critical one, the more re-reflections the signal experiences during propagation and the closer the propagation trajectory is to the outer generatrix of the workpiece. It should be taken into account that with each reflection part of the energy is dissipated, therefore, for large workpiece diameters (more than -100 mm), it is necessary to use several transducers located along the generatrix perimeter. The width of the radiation pattern depends on the size of the emitter. In the case of a wide diagram, it turns out that the ultrasonic signal falls on the surface of the workpiece at different angles and simultaneously several types of waves arise that propagate at different speeds. Therefore, in the case when it is necessary to determine the localization of defects, transducers with a narrow diagram should be used. In order to cover a large part of the diameter of the workpiece, it is necessary to use several transducers at different angles (in the case of narrowly directed transducers).

When monitoring near-surface defects in workpieces with a diameter of less than -20 mm, it is advisable to control with an ultrasonic beam propagating in a spiral. Excitation and signal reception in this case are carried out by a transducer inclined with respect to the axial line at an angle of 0 (Fig. 3). The angle of inclination of the transducer 0 and, accordingly, the pitch of the helix depend on the width of the radiation pattern.

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Rice. Fig. 2. Scheme of ultrasonic testing of near-surface defects of a cylindrical billet: / - controlled product; 2 - converter; 3 - control area; a12 - angles of incidence of the acoustic beam; (3, 2 - angles of input of the acoustic beam; L/] r - thickness of the controlled

Pipe inspection for the most common longitudinal defects is carried out by analogy with the workpiece, as shown in Fig. 2. In contrast to the blank for a transverse wave, a kind of waveguide is created in the pipe. As it propagates, it undergoes a series of successive reflections. In this case, all extended defects are detected quite effectively. In addition, conditions are created on the inner surface of the pipe for the excitation of a surface wave, which can give significant reflections from scratches on this surface that are not defects. To eliminate the registration of these defects, we have developed a special signal processing algorithm using several converters. The control scheme is shown in fig. 4. Each of the converters operates in the mode of radiation - reception. The transducers are located in such a way as to ensure the separation in time of the signal of the shear wave propagating inside the pipe wall from the signals of the initiated surface wave. The insertion angle and the number of transducers are determined by the pipe diameter and wall thickness. When using such a multi-channel system, there is no need to rotate the pipe, since the entire volume is controlled in one pass. Control over the presence of acoustic contact is carried out either by a shadow signal that runs around the entire pipe, or in the case of a large pipe diameter, due to a signal from the transducer to the transducer. Registration of impulses is carried out in a given time interval according to the amplitude feature. Usually, with this method of control, one defect gives two or more reflections. The decision on defectiveness is carried out programmatically based on the analysis of the time of arrival of signals from defects to the transducers. As can be seen from fig. 4, the signals from the defect are located symmetrically with respect to the signal that ran around the entire perimeter of the pipe in a circle. Moreover, the difference in the time of arrival of signals from a defect for different transducers remains constant and depends on the spacing of the transducers along the pipe perimeter. Here / is the serial number of the transducer. During the control, the propagation time of the signal from the defect is measured?,k (k is the number assigned to the defect), the differences A1 are calculated

to, a comparison is made of different

Rice. Fig. 3. Scheme of control of workpieces of small diameter using an ultrasonic signal propagating in a spiral: 1 - controlled product; 2 - control zone; 3 - primary converter; 0 - angle of inclination of the incident ultrasonic beam

and a decision is made on the presence of a defect. Two methods are used for sequential switching of converters. The choice of method is determined by several factors. Firstly, the ratio between the sensitivity and control speed, and secondly, the size of the controlled pipe, and hence the number of transducers. One way ~ is to use multiple genepyattim blocks - -------

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Rice. Fig. 4. Scheme of pipe control by transverse waves using several transducers (a); view of inspection results on the flaw detector screen (sweep type A) (b): 1-5 - primary transducers; b - defect; 7 - surface wave; 8 - transverse waves; 9 - setting pulse; 10 - shadow signal when the wave passes along the entire perimeter; 11, 12 - signals from a defect for transducer 7; 13, 14 - signals from a defect for transducer 2

information processing, the second is the separation of the frequency of the control pulses, i.e. in this case, for example, when the pulse repetition rate from the generator is 1 kHz, they are sent in a cycle to different converters. If there are two transducers (emitters - receivers), then each operates at a frequency of 500 Hz, if four,

then 250 Hz, etc. The modern electronic element base makes it possible to implement this process.

In some cases, when the defective level of defects is tens of square millimeters, the control and decision-making process can be greatly simplified. In this case, the shadow signal of the transverse wave propagating in the pipe wall is analyzed. The energy that is spent on the formation of a surface wave remains constant and does not affect the magnitude of the shadow signal. If a defect is detected and its location is determined, if necessary, an additional analysis of its size by the echo method can be carried out. In addition, the shadow method is more sensitive to delamination-type defects, i.e. defects that have arisen after rolling and give a slight echo due to their orientation. Delamination defects can be detected by a direct or dual-coupled transducer when vibrations are introduced from the outer surface, with pipe wall thicknesses exceeding -10 mm. This procedure can be combined with measuring the pipe wall thickness.

The control of thin-walled pipes is effectively carried out not by transverse, but by normal waves (Lamb waves). These are waves in plates that are a combination of longitudinal and transverse waves. The day of their excitation, it is necessary to introduce elastic vibrations at a certain angle to the surface. For each thickness of the plate, or in our case the pipe wall, there is an angle of entry at which a certain normal wave mode is excited at a given frequency with a corresponding propagation velocity. There are symmetric and asymmetric modes with corresponding numbers. When the symmetric mode propagates, the wall profile changes, while the asymmetric mode causes bending. The difficulty of the method when using pipe control is to excite a wave of a given mode, and not a whole spectrum of oscillations, which is difficult to understand. This is due to the finite size of the ultrasonic beam. It turns out that it falls on the surface of the pipe at different angles, and the smaller the diameter of the pipe, the greater the spread of angles. Therefore, a necessary condition for successful control is the focusing of the acoustic beam.

Separately, one should dwell on especially thick-walled pipes, especially when the wall thickness exceeds 20% of the diameter. This is related to the fact

that the minimum angle at which a shear wave can be excited is in the range of 27-33°. It depends on the material of the pipe, more precisely on the speed of sound propagation in this material. Accordingly, there comes a moment (i.e., the wall thickness reaches a certain limit) at which it becomes impossible to organize internal re-reflection of transverse waves so that they can propagate, as in a waveguide. In this case, it is possible to use longitudinal waves when entering up to the first critical angle. Of course, the sensitivity decreases, but the technical requirements for such pipes are also different. In this case, control is organized according to the same principles, as shown in Fig. 4, only using transducers that excite longitudinal waves.

In any case, when organizing the control of pipes in an automated mode, in order to achieve a certain sensitivity and the necessary productivity, the general concept of control must be tied to a specific production. To do this, the conditions for possible defect formation for a given production process should be investigated, and control schemes should be determined in accordance with this. A binding was made to the equipment on which pipes are produced and the stage of the process was determined at which it is possible to carry out control based on technical and economic

logical expediency, i.e. each installation for pipe inspection, despite the general approaches, is made individually for a given production. In all cases, coolant can be used as an immersion medium for introducing acoustic vibrations. Control can be carried out with full and partial immersion or jet acoustic contact, can be combined with cooling. Pipe wall thickness measurement is combined with defect inspection or can be performed as a separate unit. With the described organization of control, different ways of presenting the results are possible, starting with a red light or a siren in case of marriage, to recording the results in a computer with reference to the localization of defects along the length of the pipe and sending a signal to the actuators.

Literature

1. Krautkremer J., Krautkremer G. Ultrasonic testing of materials: Ref. Moscow: Metallurgy, 1991.

2. Devices for non-destructive quality control of materials and products: Ref. / Ed. V.V. Klyuev. M.: Mashinostroenie, 1976.

3. Gurvich A.K., Kuzmina L.I. Reference radiation patterns of ultrasonic flaw detectors. Kyiv: Technique, 1980.

4. Konovalov G., Mayorov A., Prohorenko P. The Systems for Automated Ultrasonic Testing // 7"" European Conference on NDT. Copenhagen, 1998.

For industrial engineering communications, a number of standards have been introduced that imply a rather strict check of connections. These techniques are being transferred to privately owned systems. The application of methods allows to avoid emergency situations and to carry out external and hidden installation with the required level of quality.

Input control

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

The mentioned standards imply the inspection of pipes, regardless of the material from which they are made. Inbound controlling implies the rules for checking the received lot. Checking of welded joints is carried out as part of the acceptance of works on the installation of communications. The described methods are mandatory for use by construction and installation organizations when commissioning residential, commercial and industrial facilities with water supply and heating systems. Similar methods are used where quality control of pipes in industrial-type communications operating as part of equipment is necessary.

Sequence of implementation and methodology

Acceptance of products after delivery is an important process, subsequently guaranteeing the absence of wasteful costs for the replacement of tubular products and accidents. A thorough check is subject to both the quantity of products and their features. Quantitative verification allows you to take into account the entire consumption of products and avoid unnecessary costs associated with excessive standards and irrational use. The influence of the human factor should not be overlooked.

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

The sequence of input measures is as follows:

• Verification of the certificate and conformity of the marking;
• Random testing of samples is carried out when quality is in doubt. The magnitude of the yield strength in tension and elongation during mechanical rupture is investigated;
• Even if there is no doubt about the supply, a small number of test samples are taken, within 0.25-2% of the batch, but not less than 5 pcs. When using products in bays, cut off 2 m;
• The surface is inspected;
• Inspected for blisters and cracks;
• Measure the typical dimensions of thicknesses and walls with a micrometer or caliper.

During an official inspection by a commercial or government organization, a protocol is drawn up upon the fact of the procedure.

Non-destructive testing - features

Non-destructive methods are used in functioning engineering communication systems. Particular attention is paid to the real state of the metal and welded joints. Operational safety is determined by the quality of welding seams. During long-term operation, the degree of damage to the structure between the joints is investigated. They can be damaged by rust, which leads to thinning of the walls, and clogging of the cavity can lead to an increase in pressure and a pipeline burst.

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

In pipeline studies, pipe control methods are used:

With the help of this equipment, the development of cracks or violation of integrity is monitored. Moreover, the main advantage is the identification of hidden defects. Obviously, each of these methods shows high efficiency on certain types of damage. An eddy current flaw detector is, to some extent, universal and optimal in terms of cost.

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

Conclusion

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

GOST 17410-78

Group B69

INTERSTATE STANDARD

TESTING NON-DESTRUCTIVE

METAL SEAMLESS CYLINDRICAL PIPES

Methods of ultrasonic flaw detection

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

ISS 19.100
23.040.10

Introduction date 1980-01-01

INFORMATION DATA

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

2. APPROVED AND INTRODUCED BY Decree of the USSR State Committee for Standards of 06.06.78 N 1532

3. REPLACE GOST 17410-72

4. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

	Number of paragraph, subparagraph

5. The limitation of the validity period was removed according to protocol N 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 detect various defects (such as metal discontinuity and homogeneity) 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, Rev. N 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 piece of a defect-free pipe made of the same material, the same size and having the same surface quality as the tested pipe, in which artificial reflectors are made.

Notes:

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

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

3. If the pipe metal is non-uniform in terms of 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 the attenuation should be specified in the technical documentation for the control.

1.7.1. Artificial reflectors in standard samples for adjusting the sensitivity of ultrasonic equipment for monitoring longitudinal defects must comply with drawings 1-6, for monitoring transverse defects - drawings 7-12, for monitoring delamination-type defects - drawings 13-14.

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

1.7.2. Artificial reflectors of the risk type (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 segment 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, its dimensions depend on the method of control and on the type of equipment used and should be provided for in the technical documentation for control.

Damn.1

Damn.3

Damn.8

Damn 11

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

Triangular marks (drawings 1, 2, 7, 8, execution 2) are used to control pipes with a nominal wall thickness of any value.

(Changed edition, Rev. N 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 Fig. 13) and flat-bottomed holes (see Fig. 14) are used to adjust the sensitivity of ultrasonic equipment to detect defects such as delaminations with a pipe wall thickness of more 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 excludes their mutual influence on each other when adjusting the sensitivity of the equipment.

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

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

For risks:

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

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

- line width, mm: no more than 1.5.

Notes:

1. The length of the risk is given for its part, which has a constant depth within 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 for in the technical documentation for testing.


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

(Changed edition, Rev. N 1).

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

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

When testing pipes with a large ratio of wall thickness to the outer diameter, the dimensions of the artificial reflector on the inner surface should be specified in the technical documentation for testing, however, it is allowed to increase the dimensions of the artificial reflector on the inner surface of the standard sample, compared with the dimensions of the artificial reflector on the outer surface of the standard sample, not more than 2 times.

1.9. Standard samples with artificial reflectors are divided into control and working ones. Adjustment of ultrasonic equipment is carried out according to working standard samples. Control samples are designed 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 measuring the parameters of artificial reflectors directly at least once every 3 months.

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

Working standards that are not used within the specified period are checked before they are used.

If the amplitude of the signal from the artificial reflector and the level of acoustic noise of the sample do not match the control one by ±2 dB or more, it is replaced with a new one.

(Changed edition, Rev. N 1).

2. PREPARATION FOR CONTROL

2.1. Before testing, 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 must not have burrs.

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

(Changed edition, Rev. N 2).

2.2. Pipe surfaces must not have delaminations, dents, nicks, traces of punching, leakage, splashes of molten metal, corrosion damage and must comply with the requirements for surface preparation specified in the technical documentation for inspection.

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

(Changed edition, Rev. N 1).

2.4. Before the control, 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 verification should be provided in the technical documentation for the ultrasonic testing tools used.

2.5. The sensitivity of the ultrasonic equipment is adjusted according to working standard samples with artificial reflectors indicated in Fig. 1-14 in accordance with the technical documentation for control.

Setting the sensitivity of automatic ultrasonic equipment according to working standard samples must meet the conditions of production control of pipes.

2.6. The adjustment of the sensitivity of the automatic ultrasonic equipment according to the standard sample is considered complete if at least five times the sample is passed through the installation in the steady state, 100% registration of the artificial reflector occurs. In this case, if the design of the pipe pulling mechanism allows, the standard sample is rotated each time by 60-80° relative to the previous position before entering the installation.

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

3. CONTROL

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

(Changed edition, Rev. N 1).

3.2. The introduction of ultrasonic vibrations into the metal of the pipe is carried out by immersion, contact or slotted method.

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

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

3.4. The control of pipe metal for the absence of defects is achieved by scanning the surface of the controlled pipe 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 testing, it is allowed to use multichannel monitoring schemes, while the transducers in the control plane must be located so as to exclude their mutual influence on the results of testing.

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

3.6. Checking the correct setting of the equipment according to 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 checks is determined by the type of equipment used, the control scheme used, and should be established in the technical documentation for control. If a misalignment is detected between two checks, the entire batch of inspected pipes is subject to re-inspection.

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

3.7. The method, basic parameters, transducer switching circuits, the method of introducing ultrasonic vibrations, the sounding circuit, the 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, Rev. N 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 by artificial reflectors, drawings 1-6);

b) longitudinal defects during the propagation of ultrasonic vibrations in two directions towards each other (tuning by artificial reflectors, drawings 1-6);

c) longitudinal defects in the propagation of ultrasonic vibrations in two directions (tuning by artificial reflectors, drawings 1-6) and transverse defects in the propagation of ultrasonic vibrations in one direction (tuning by artificial reflectors, drawings 7-12);

d) longitudinal and transverse defects in the propagation of ultrasonic vibrations in two directions (setting on artificial reflectors, drawings 1-12);

e) defects such as delaminations (tuning by 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 FORMULATION OF THE RESULTS OF CONTROL

4.1. The evaluation of the continuity of the pipe metal is carried out based on the results of the analysis of 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:

- size and material of the pipe;

- scope of control;

- technical documentation on which control is carried out;

- control scheme;

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

- numbers of standard samples used for tuning;

- type of equipment;

- nominal frequency of ultrasonic vibrations;

- converter type;

- scan options.

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 journal of ultrasonic testing of pipes is given in Appendix 3.

(Changed edition, Rev. N 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 consumer electrical installations and technical safety rules for the operation of consumer electrical installations" * 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 converters 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 Fig.1-16: G- output to the generator of ultrasonic vibrations; P- output to the receiver.

Damn.4

Damn.6

Devil 16

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

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

ANNEX 1a
Reference

THE 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	Measurement method	Reflector parameters, mm
Risk (triangular or rectangular)
Segment 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, which are manufactured in this standard sample.

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

3. The column "Measurement method" indicates the method of measurement: direct, with the help of casts (plastic impressions), with the help of witness samples (amplitude method) and the instrument or device that was used to measure.

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


APPENDIX 1a. (Introduced additionally, Rev. N 1).

APPENDIX 2 (recommended). Map of ultrasonic testing of pipes with manual scanning

	Number of technical documentation for control
	Pipe size (diameter, wall thickness)
	Material Grade
	Number of technical documentation regulating the standards for evaluating suitability
	Scope of control (direction of sounding)
	Converter type
	Converter frequency
	Beam incidence angle
	Type and size of artificial reflector (or standard sample number) to adjust fixation sensitivity
	and search sensitivity
	Flaw detector type
	Scan parameters (step, control speed)

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

Contact date role			Package number, presentation, certificate fiqat	If- number of pipes, pcs.	Control parameters (reference sample number, dimensions of artificial defects, type of installation, control scheme, operating frequency of ultrasonic testing, transducer size, control step)	Check rooms pipes	Ultrasound results		Signature defective- scopist (operator- controller) and Quality Control Department
	Once- measures, mm	Mate- rial					pipe numbers without de- effects	numbers of pipes with defects tami

APPENDIX 3. (Changed edition, Rev. N 1).



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

Recently, the state authorities of the Russian Federation have declared a “pivot to the East” and potential close cooperation between Russian manufacturers / customers and Chinese ones. For high-quality joint work with representatives of the PRC, it is necessary to speak the same language with them, and in particular, to be familiar with the terminology used by both parties and standard regulatory documentation. In this article, we would like to summarize our experience of interaction with colleagues from the People's Republic of China on one local issue - diagnosing casing strings, and use it as an example to consider the similarities and differences in the regulatory documentation of the Russian Federation and China.

Casing pipes are used for fixing oil and gas wells during their construction and operation. Casing pipes are connected to each other by means of coupling or couplingless (integral) threaded connections. At the construction site, a multi-stage construction quality control is always carried out, consisting of the following operations: control of the availability of accompanying documentation (certificate); verification of conformity of the data of the certificate with the marking of pipes; visual control; instrumental control; unbrakable control; mandrel control; hydraulic test.

All quality control activities should be governed by the manufacturer's instructions, which should include the appropriate methodology and quantitative or qualitative acceptance criteria. The instructions for non-destructive testing shall comply with the requirements of this specification and the requirements of national and international standards selected by the manufacturer.

On the territory of the Russian Federation, the main GOST 632-1980 and GOST 53366-2009 are currently in force (Cancelled, from 01.01.2015 use GOST 31446-2012. By order of the Federal Agency for Technical Regulation and Metrology dated 10.22.2014 No. 1377-st - restored on the territory of the Russian Federation from 01/01/2015 to 01/01/2017), regulating the requirements for non-destructive testing and the levels of control of seamless and electric-welded pipes. All casing pipes must be checked for defects along their entire length (from end to end) by non-destructive testing methods.

Casing pipes must not have defects that, according to GOST R 53366-2009, refer to unacceptable defects, and must comply with the requirements established in this standard. Standard pipe NDT methods are traditional, proven methods and include NDT procedures that are widely used to test tubular products around the world. However, the use of other methods and procedures of non-destructive testing capable of detecting defects is allowed, for example, for the use of pipes in wells with special operating conditions. In such cases, it is recommended to use other non-destructive testing methods that allow you to confirm the required quality of the pipes and their suitability for running into the well.

Consider the non-destructive testing methods for casing strings used in the Russian Federation and China:

1) Ultrasonic control (ultrasonic method)

Ultrasound propagates over the entire circumference of the material. The acoustic characteristics of the material and internal structural changes are reflected in the propagation of ultrasonic waves. The registration of the signal and its analysis gives an idea of ​​the degree of damage to the material. GOST 53366-2009 specifies only international standards, according to which casing strings should be inspected: ISO 9303, ISO 9503 and ASTM E 213. However, in GOST 13680-2011, to detect delaminations, the projection area of ​​which on the outer surface is not more than 260 mm 2 , it is proposed to act in accordance with ISO 10124:1994 (Table 1).

At the same time, standard methods of ultrasonic non-destructive testing are in force in Russia: GOST R ISO 10332-99 “Seamless and welded steel pressure pipes (except for pipes made by submerged arc welding)”, GOST 12503-75 “Steel. Methods of ultrasonic control. General requirements”, GOST 14782-86 “Non-destructive testing. Connections are welded. Ultrasonic Methods” (Outdated on the territory of the Russian Federation from 07/01/2015. Use GOST R 55724-2013), GOST R ISO 10893-12-2014 “Seamless and welded steel pipes. Part 12. Ultrasonic method of automated wall thickness control around the entire circumference”, however, they are not used to detect casing defects. Mostly, the international standards of ultrasonic non-destructive testing method listed above are used, while in China, the inspection of the integrity of casing pipes is detected in accordance with international and / or domestic standards 1 .

Table 1 presents the most important standards for ultrasonic testing of casing strings, from the standard methods for non-destructive testing of pipes, used both in Russia and in China.

Table 1

Standard number	Name of the standard	Standard number	Name of the standard
			Seamless and welded steel pipes (except for pipes obtained by submerged arc welding) for pressure. Ultrasonic inspection of the entire peripheral surface to detect longitudinal imperfections Substitute designation: ISO 10893-10:2011 Non-destructive testing of steel pipes. Part 10: Full circumference automatic ultrasonic testing of seamless and welded steel pipes (other than submerged arc welded pipes) to detect longitudinal and/or transverse defects
			Standard Method for Ultrasonic Inspection of Metal Pipes
	Substitute designation: ISO 10893-10:2011 Non-destructive testing of steel pipes. Part 10: Full circumference automatic ultrasonic testing of seamless and welded steel pipes (other than submerged arc welded pipes) to detect longitudinal and/or transverse defects		Pipes steel seamless pressure head. Ultrasonic inspection of the entire peripheral surface to detect transverse imperfections Substitute designation: ISO 10893-10:2011 Non-destructive testing of steel pipes. Part 10: Full circumference automatic ultrasonic testing of seamless and welded steel pipes (other than submerged arc welded pipes) to detect longitudinal and/or transverse defects
	Seamless and welded steel pressure pipes (except for pipes made by submerged arc welding). Ultrasonic inspection method for the detection of layered imperfections Substitute designation: ISO 10893-8:2011 Non-destructive testing of steel pipes. Part 8: Automatic ultrasonic testing of seamless and welded steel pipes to detect delamination defects		Non-destructive testing of steel pipes. Automated ultrasonic testing of seamless and welded steel pipes (except for pipes obtained by submerged arc welding) for tightness
			Unbrakable control. Ultrasonic control. General principles
		ISO 10893-3:2011
			Steel pipes obtained by electric contact welding and induction welding, pressure. Ultrasonic inspection of the weld to detect longitudinal imperfections Substitute designation: ISO 10893-11:2011 Non-destructive testing of steel pipes. Part 11: Automatic ultrasonic testing of welded steel pipes for detection of longitudinal and/or transverse defects
		ISO 10893-10:2011	Non-destructive testing of steel pipes. Part 10: Full circumference automatic ultrasonic testing of seamless and welded steel pipes (other than submerged arc welded pipes) to detect longitudinal and/or transverse defects
			Standard Method for Ultrasonic Inspection of the Weld Zone of Welded Pipeline and Tubing
			Seamless steel pipes. Ultrasonic control method (Analogue: ISO 9303-1989 Seamless and welded steel pipes (except pipes obtained by submerged arc welding) for pressure. Ultrasonic inspection of the entire peripheral surface to detect longitudinal imperfections)
		SY/T 6423.6-1999	Oil and gas industry. Pressure steel pipes, non-destructive testing methods. Seamless and welded steel pipes (except for pipes obtained by submerged arc welding), ultrasonic method for testing layered imperfections (Similar to ISO 10124-1994 Seamless and welded steel pressure pipes (except pipes manufactured by submerged arc welding) Replacement designation: SY/T 6423.4-2013 Oil and gas industry. Non-destructive testing methods - Part 4: Automatic ultrasonic testing of layered imperfections in seamless and welded steel pipes
		SY/T 6423.7-1999	Oil and gas industry. Steel pressure pipes, non-destructive testing methods. Seamless and welded steel pipes, ultrasonic testing of pipe ends to detect layered imperfections (Analogue: ISO 11496-1993 Seamless and welded steel pipes - Ultrasonic testing of pipe ends to detect lamellar imperfections) Replacement designation: SY/T 6423.4-2013 Oil and gas industry. Non-destructive testing methods - Part 4: Automatic ultrasonic testing of layered imperfections in seamless and welded steel pipes

2) Magnetic control (magnetic flux leakage method)

The next method of non-destructive testing, which is recommended to be used in accordance with the requirements of GOST 53366-2009, is the method of magnetic flux leakage.

Magnetic flaw detection of casing pipes by the scattered flux method is based on the detection of magnetic leakage fluxes in a ferromagnetic material with high magnetic permeability by measuring the changing characteristics after the product is magnetized. After magnetization, the magnetic flux, propagating through the object under study and encountering a defect on its way, goes around it due to the fact that the magnetic permeability of the defect is much lower than the magnetic permeability of the base metal. As a result, part of the magnetic force lines is displaced by the defect to the surface, forming a local stray magnetic flux.

Magnetic testing methods cannot detect defects that cause perturbation in the distribution of magnetic flux lines of force without the formation of a local leakage flux. The perturbation of the flux depends on the size and shape of the defect, the depth of its occurrence and its orientation relative to the direction of the magnetic flux. Surface defects located perpendicular to the magnetic flux create significant stray fluxes; defects oriented along the direction of magnetic field lines practically do not cause the appearance of scattering fluxes. The presence of longitudinal and transverse defects leads to the need to carry out double control using combined magnetization.

Table 2 presents the standards for magnetic flaw detection by the method of magnetic flux leakage. Table 2 does not present the standard methods of non-destructive testing in force in the Russian Federation: GOST R 55680-2013 “Non-destructive testing. Ferroprobe method” (effective from 07/01/2015, replacing GOST 21104-75); GOST R ISO 10893-3-2016 “Seamless and welded steel pipes. Part 3. Automated testing by the method of magnetic flux scattering over the entire surface of pipes made of ferromagnetic steel to detect longitudinal and (or) transverse defects” (date of entry into force 01.11.2016).

table 2

Standards in force on the territory of the Russian Federation		Standards in force in China
Standard number	Name of the standard	Standard number	Name of the standard
			Seamless and welded steel pipes (except for pipes obtained by submerged arc welding) for pressure. Flux circumferential scattering test of ferromagnetic steel pipes using a magnetic transducer to detect longitudinal defects Substitute designation: ISO 10893-3:2011 Non-destructive testing of steel pipes. Part 3: Automatic full circumference magnetic flux leakage testing of seamless and welded ferromagnetic steel pipes (except submerged arc welded pipes) to detect longitudinal and/or transverse defects
			Standard Test Method for Ferromagnetic Tubular Products by Magnetic Flux Leakage
	Substitute designation: ISO 10893-3:2011 Non-destructive testing of steel pipes. Part 3: Automatic full circumference magnetic flux leakage testing of seamless and welded ferromagnetic steel pipes (except submerged arc welded pipes) to detect longitudinal and/or transverse defects		Pipes steel seamless pressure head. Inspection of the entire peripheral surface of ferromagnetic steel pipes by examining stray magnetic fields to detect transverse imperfections Substitute designation: ISO 10893-3:2011 Non-destructive testing of steel pipes. Part 3: Automatic full circumference magnetic flux leakage testing of seamless and welded ferromagnetic steel pipes (except submerged arc welded pipes) to detect longitudinal and/or transverse defects
			Steel Pipe - Magnetic Flux Leakage Method
		ISO 10893-3:2011	Non-destructive testing of steel pipes. Part 3: Automatic full circumference magnetic flux leakage testing of seamless and welded ferromagnetic steel pipes (except submerged arc welded pipes) to detect longitudinal and/or transverse defects

3) Eddy current testing (eddy current method)

The control by the eddy current method is a field of eddy currents formed by a ferromagnetic coil located near the surface of the controlled object; analysis of changes in the electromagnetic field of eddy currents under the influence of certain defects. The method is only applicable to conductive material. Eddy current testing can be used to test pipes, welds and cracks in the surface layer of the overlay, and indirectly measure the length of the defect.

Table 3 presents the standards for testing by the eddy current method; there are no Russian and Chinese specialized standards for casing string flaw detection by this method. However, a number of standards are in force on the territory of the Russian Federation: GOST 24289-80 “Non-destructive eddy current testing. Terms and definitions”, GOST R ISO 15549-2009 “Non-destructive testing. Eddy current control. Basic provisions”, GOST R ISO 12718-2009 “Non-destructive testing. Eddy current control. Terms and definitions”, GOST R 55611-2013 “Non-destructive eddy current testing. Terms and Definitions". On the territory of the People's Republic of China, this method is standardized only for pipes of other classes (range).

Table 3

Standards in force on the territory of the Russian Federation		Standards in force in China
Standard number	Name of the standard	Standard number	Name of the standard
			Seamless and welded steel pipes (except for pipes obtained by submerged arc welding) for pressure. Eddy current testing for imperfection detection Substitute designation: ISO 10893-2:2011 Non-destructive testing of steel pipes. Part 2: Automatic method for eddy current testing of seamless and welded steel pipes (except pipes obtained by submerged arc welding) for defect detection
			Standard Method for Eddy Current Inspection of Steel Tubular Products Using Magnetic Saturation
		ISO 10893-2:2011	Non-destructive testing of steel pipes. Part 2: Automatic method for eddy current testing of seamless and welded steel pipes (except pipes obtained by submerged arc welding) for defect detection
			Unbrakable control. Eddy current control. Dictionary
			Unbrakable control. Eddy current test. General principles
		BS-EN-0246-3-2000	Non-destructive testing of steel pipes. Part 3: Automatic method for eddy current inspection of steel seamless and welded (except submerged arc welded) pipes for defect detection
			Steel pipe - Eddy current testing (Analogue: ISO 9304-1989 Seamless and welded steel pipes (except pipes obtained by submerged arc welding) for pressure purposes. Eddy current testing to detect imperfections)
		GB/T 12604.6-2008	Unbrakable control. Terminology. Eddy current method
			Unbrakable control. Pulsed eddy current method
		JB/T 4730.6-2005	Non-destructive testing of pressure equipment - Part 6: Eddy current method Substitute designation: NB/T 47013.6-2015 Non-destructive testing of pressure equipment - Part 6: Eddy current method

4) Magnetic control (magnetic particle method)

Magnetic particle control - the use of magnetic powder, which is adsorbed in the places of defects, forming a "magnetic mark" - rollers of black magnetic powder, control is carried out visually. The method reflects surface and internal defects, while the sensitivity of the method does not depend on the color and metallization of the surface. The magnetic particle method is preferable for ferromagnetic materials in comparison with the method of penetrating substances, as it is more efficient and easy to use. The main disadvantage is the limited access to the ferromagnetic material, in order to fully examine the surface, special equipment and a power source are required. After testing, residual magnetization is observed, which is difficult to eliminate. Table 4 shows international standards for magnetic particle inspection of casing strings, Chinese standards for inspection by this method used in mechanical engineering: quality control of equipment under pressure by magnetic particle method. Table 4 also does not include standards in force in Russia, because they were not referenced in the defining GOST 53366-2009: GOST R 56512-2015 “Non-destructive testing. Magnetic particle method. Typical technological processes” (date of entry into force 01.11.2016), GOST R ISO 9934-1-2011 “Non-destructive testing. Magnetic particle method. Part 1. Basic requirements”, GOST R ISO 9934-2-2011 “Non-destructive testing. Magnetic particle method. Part 2. Defectoscopy materials”, GOST 21105-87 “Non-destructive testing. Magnetic particle method”, GOST R ISO 10893-5-2016 “Seamless and welded steel pipes. Part 5. Magnetic particle inspection of ferromagnetic steel pipes to detect surface defects” (date of entry into force 01.11.2016).

Table 4

Standards in force on the territory of the Russian Federation		Standards in force in China
Standard number	Name of the standard	Standard number	Name of the standard
			Pipes steel pressure head seamless and welded. Inspection of the pipe body by magnetic particle method to detect surface imperfections Substitute designation: ISO 10893-5:2011 Non-destructive testing of steel pipes. Part 5: Method for magnetic particle inspection of seamless and welded ferromagnetic steel pipes to detect surface defects
			Guide to Magnetic Particle Inspection
	Pipes steel pressure head seamless and welded. Inspection of pipe ends by magnetic particle method to detect layered imperfections Substitute designation: ISO 10893-5:2011 Non-destructive testing of steel pipes. Part 5: Method for magnetic particle inspection of seamless and welded ferromagnetic steel pipes to detect surface defects	ISO 10893-5:2011	Non-destructive testing of steel pipes. Part 5: Method for magnetic particle inspection of seamless and welded ferromagnetic steel pipes to detect surface defects
		GB/T 12604.5-2008	Unbrakable control. Terminology. Magnetic particle method
		JB/T 4730.4-2005	Non-destructive testing of pressure equipment - Part 4: Magnetic particle method Substitute designation: NB/T 47013.4-2015 Non-destructive testing of pressure equipment - Part 4: Magnetic particle method

5) Inspection by penetrating substances (capillary flaw detection)

The method of penetrating substances is based on the penetration of a special liquid - a penetrant - into the cavity of surface and through discontinuities of the test object, followed by the extraction of the penetrant from the defects. The most common method is the capillary method, which is suitable for diagnosing objects made of metals and ceramics. The duration of flaw detection depends on the physical properties of the liquid, the nature of the detected defects and the method of filling the defect cavities with liquid. Within half an hour, surface fatigue, stress corrosion cracking and weld defect can be detected, the method allows you to determine the size of the crack.

GOST 53366-2009 does not specify the standards for the capillary inspection method, for detecting casing defects, but this standard allows the use of other methods and methods of non-destructive testing. At the same time, GOST R ISO 13680-2011 recommends using ISO 12095 or ASTM E 165, which are given in Table 5. Internal Russian standards for non-destructive testing by penetrating liquids have been developed and are in effect, but so far they have not been used for casing string inspection: GOST R ISO 3059-2015 “Non-destructive testing. Penetrating control and magnetic particle method. Selection of inspection parameters” (date of entry into force 06/01/2016), GOST R ISO 3452-1-2011 “Non-destructive testing. Penetrating control. Part 1. Basic requirements”, GOST R ISO 3452-2-2009 “Non-destructive testing. Penetrating control. Part 2. Penetrant testing”, GOST R ISO 3452-3-2009 “Non-destructive testing. Penetrating control. Part 3. Test samples”, GOST R ISO 3452-4-2011 “Non-destructive testing. Penetrating control. Part 4. Equipment”, GOST R ISO 12706-2011 “Non-destructive testing. Penetrating control. Dictionary”, GOST 18442-80 “Non-destructive testing Capillary methods General requirements”.

Table 5 lists standards related to this casing diagnostic method. There are no internal Chinese standards for casing penetration testing.

Table 5

Standards in force on the territory of the Russian Federation		Standards in force in China
Standard number	Name of the standard	Standard number	Name of the standard
	Steel welded and seamless pressure pipes. Penetration test Substitute designation: ISO 10893-4:2011 Non-destructive testing of steel pipes. Part 4: Liquid penetrant inspection of seamless and welded steel pipes for the detection of surface defects	ISO 10893-4:2011	Non-destructive testing of steel pipes. Part 4: Liquid penetrant inspection of seamless and welded steel pipes for the detection of surface defects
	Standard Practice for Capillary Control. General industry	GB/T 12604.3-2005	Unbrakable control. Terminology. capillary method (Analogue: ISO 12706-2009 Non-destructive testing. Capillary testing. Dictionary) Substitute designation： GB/T 12604.3-2013 Non-destructive testing. Terminology. capillary method
		GB/T 18851.1-2012	Non-destructive testing - Capillary method - Part 1: General principles (Analogue: ISO 3452-1-2008 Non-destructive testing - Penetrating liquid method - Part 1: General principles)
		JB/T 4730.5-2005	Non-destructive testing of pressure equipment - Part 5: Penetrating liquid method Substitute designation： NB/T 47013.5-2015 Non-destructive testing of pressure equipment - Part 5: Penetrating liquid method

6) X-ray control (radiographic method)

The radiographic method involves the use of x-ray radiation passing through the weld metal and creating an image on the radiographic film that displays the presence of various defects. The degree of exposure of the film will be greater at the locations of the defects.

In accordance with GOST ISO 3183-2012 “Steel pipes for oil and gas industry pipelines. General Specifications” X-ray control at a distance of at least 200 mm from the end of the pipe must be subjected to a weld of each end of the pipes. Pipes are subjected to this method of control:

• with one or two longitudinal seams or one spiral seam obtained by a combination of gas-shielded metal arc welding and submerged arc welding;
• with one or two longitudinal welds or one spiral weld obtained by submerged arc welding.

Table 6 provides relevant standards related to radiographic inspection of a casing weld. Part of the standards for the control of pipe welds is not specified.

Table 6

Standards in force on the territory of the Russian Federation		Standards in force in China
Standard number	Name of the standard	Standard number	Name of the standard
	Pressure steel pipes obtained by submerged arc welding. Radiographic inspection of the weld to detect imperfections Substitute designation: ISO 10893-6:2011 Non-destructive testing of steel pipes. Part 6. Radiographic inspection of the seam of welded steel pipes for the detection of defects	ISO 10893-6:2011	Non-destructive testing of steel pipes. Part 6. Radiographic inspection of the seam of welded steel pipes for the detection of defects
	Radiographic Testing Guide	ISO 10893-7:2011	Non-destructive testing of steel pipes. Part 7: Digital radiographic inspection of the seam of welded steel pipes for the detection of defects
		JB/T 4730.2-2005	Non-destructive testing of pressure equipment - Part 2: X-rays Substitute designation: NB/T 47013.2-2015 Non-destructive testing of pressure equipment - Part 2: X-rays
		GB/T 12604.2-2005	Non-destructive control method. Terminology. Radiographic control (Analogue: ISO 5576:1997 Non-destructive testing - Industrial radiology using x-rays and gamma rays - Vocabulary)

1. In the Russian Federation and China, when examining casing pipes for defects by various non-destructive testing methods, they are mainly guided by the international standards ISO and ASTM.
2. Non-destructive testing of casing pipes is carried out in accordance with at least the same international standard in both Russia and China.
3. The main methods of non-destructive testing of casing strings according to GOST 632-1980 and GOST 53366-2009 are: ultrasonic method, magnetic flux scattering method, eddy current method and magnetic particle method.
4. On the territory of the Russian Federation and the People's Republic of China, internal standards for non-destructive testing have been developed, which are not used to detect defects in casing pipes, but are used in other industrial areas.
5. In current internal standards and newly adopted ones, one can find references to canceled or obsolete (there are replacement) versions of international and internal standards.
6. The radiographic method of non-destructive testing is used only for flaw detection of welded seams of casing pipes.

XU Jin-long, CAO Biao, HONG Wu-xing, LU Shan-sheng, FENG Jun-han, HUA Bin, YANG Shu-jie Domestic and International Standards for Non-Destructive Testing of Casing Strings / "Non-Destructive Testing Methods" 2014, Vol 36 , No. 10, pp. 72-77

Tags: eddy current testing, capillary flaw detection, penetrant testing, magnetic testing, magnetic particle testing, magnetic flux leakage method, non-destructive testing, non-destructive testing of casing pipes, casing pipe, radiographic inspection, X-ray inspection, ultrasonic inspection