CN108931577A - A kind of oil-gas transportation steel plate electromagnetic acoustic automatic checkout system and method - Google Patents

Abstract

The invention relates to the field of nondestructive testing, in particular to an electromagnetic ultrasonic automatic testing system and method for steel plates used for oil and gas transportation. The invention solves the problems that the existing detection technology cannot realize 100% detection of the steel plate for oil and gas transportation, and the detection speed is slow and the efficiency is low. The steel plate electromagnetic ultrasonic automatic detection system for oil and gas transportation of the present invention includes a plurality of EMAT transducers and a comparison test block; the plurality of EMAT transducers are divided into a main transducer group and two groups of side transducer groups, and two groups of side transducer groups The external transducer groups are respectively located on both sides of the main transducer group; the EMAT transducers of the main transducer group and the two groups of side transducer groups are both in two rows, and the two rows of EMAT transducers are arranged in a misplaced position, and Two rows of corresponding EMAT transducers keep at least 10% coincidence; the edgemost EMAT transducers on both sides of the main body transducer group and the EMAT transducers of the corresponding edge transducer group keep at least 10% coincidence; An artificial reflector is processed on the comparison test block, and the artificial reflector includes a plurality of flat-bottomed holes, a plurality of rectangular flat-bottomed grooves and at least one inclined groove.

Description

An electromagnetic ultrasonic automatic detection system and method for steel plates for oil and gas transportation

technical field

The invention relates to the field of nondestructive testing, in particular to an electromagnetic ultrasonic automatic testing system and method for steel plates used for oil and gas transportation.

Background technique

With the continuous improvement of the transmission pressure and steel grade of oil and gas transmission pipelines, the requirements for steel plates for oil and gas transmission are also continuously increasing. For example, deep-sea pipelines, large-diameter high-grade steel grade thick-walled pipelines require 100% ultrasonic testing of steel plates . Steel plates are made from slabs. Common defects in steel plates include delamination, folding, slag inclusions (miscellaneous), porosity, segregation, white spots, and cracks. The internal defects of the steel plate have an important impact on the steel plate for oil and gas transportation. For example, the effective wall thickness of the layered defect part will decrease, which will reduce the physical and mechanical properties of the part, and the discontinuity of the metal structure at the defect part will also make the product in use. Fatigue or even failure occurs in the process, which seriously affects the performance of the product. Defects such as delamination and slag inclusions (miscellaneous) at the edge of the steel plate have a greater impact on the subsequent welding quality.

At present, the detection of steel plates for oil and gas transportation in my country is mainly based on piezoelectric ultrasound, and it is difficult to achieve 100% detection, and water is required as a coupling agent.

Compared with conventional piezoelectric ultrasonic testing, electromagnetic acoustic transducer (EMAT) testing has the advantages of non-contact and non-couplant detection, high-temperature detection, easy automatic detection, fast detection speed, and high detection efficiency. By changing the structure and frequency of the probe, ultrasonic waves of various modes can be easily excited. Therefore, the electromagnetic ultrasonic automatic detection method of steel plates for oil and gas transportation has broad development prospects in the field of nondestructive testing. Combined with SH wave detection technology, the application of electromagnetic ultrasonic technology is expected to solve the problem of 100% detection, high speed, high efficiency and automatic detection of steel plates for oil and gas transportation.

Contents of the invention

The purpose of the present invention is to propose an electromagnetic ultrasonic automatic detection system and method for steel plates for oil and gas transportation, which solves the problem that the existing detection technology cannot realize 100% detection of steel plates for oil and gas transportation, and the detection speed is slow and the efficiency is low.

The technical solution of the present invention to solve the above problems is a steel plate electromagnetic ultrasonic automatic detection system for oil and gas transportation, which is special in that:

Including multiple EMAT transducers and comparison test blocks;

The plurality of EMAT transducers are divided into a main body transducer group and two sets of side transducer groups, and the two sets of side transducer groups are respectively located on both sides of the main body transducer group; the main body transducer group and the The EMAT transducers of the two groups of side transducer groups are two rows, and the two rows of EMAT transducers are arranged in a misplaced manner, and the corresponding EMAT transducers of the two rows maintain at least 10% overlap; the main body transducer group The EMAT transducers at the edge of both sides maintain at least 10% coincidence with the EMAT transducers of the corresponding edge transducer groups; the comparison test block includes a steel plate on which an artificial reflector is positioned and quantitatively processed, and the The artificial reflector includes a plurality of flat-bottomed holes, a plurality of rectangular flat-bottomed grooves and at least one inclined groove.

The chute is a wire cutting groove.

Further, the above-mentioned EMAT transducer is selected from a vertical magnetic field, a double helical coil, and an EMAT transducer that generates SH waves.

Further, the dimensions of the comparison test block are the same as those of the steel plate for oil and gas transmission to be tested.

Further, in order to facilitate transportation or processing of artificial defects, artificial reflectors are processed on two steel plates, and then the two steel plates are welded to form a comparison test block.

Further, the above-mentioned plurality of flat-bottomed holes are respectively set at the middle part of the comparison test block and the surrounding parts at a distance of 25 mm from the edge of the plate; the flat-bottomed holes set in the middle of the plate are divided into three groups, one group with a diameter of 3 mm, and the buried depth is 1.5 mm respectively. , 8.25mm, 16.5mm, 24.75mm and 31.8mm are used to test the detection system and the detection capability of electromagnetic ultrasonic transducers; for a group with an aperture of 6mm, the burial depths are 1.5mm, 8.25mm, 16.5mm and 24.75mm respectively and 31.8mm flat-bottomed holes are used to make distance-amplitude curves and evaluate the equivalent size of defects at different depths; a group with a hole diameter of 50mm and a burial depth of 16.5mm is used to simulate delamination defects in plates; the multiple rectangular The flat-bottomed groove is set in the middle of the comparison test block, width x length: 40mm x 80mm, burial depths are 8.25mm, 16.5mm and 24.75mm respectively, half of which are set in the horizontal and vertical directions, and are used to simulate defects such as folding and white spots in the plate; The chute is set in the middle of the comparison test block and runs through the width direction of the plate. Its width is 6 mm, and its buried depth is 8.25 mm, 16.5 mm, and 24.75 mm, respectively. It is used to test the scanning coverage of the electromagnetic ultrasonic transducer and the dynamic detection capability of the system. and reliability.

Further, the number of the above-mentioned flat-bottomed holes with a diameter of 50 mm is four.

In addition, the present invention also proposes a detection method of the above-mentioned electromagnetic ultrasonic automatic detection system for the steel plate used for oil and gas transportation, which is characterized in that it includes the following steps:

1) Scan and compare the test block to test the detection ability of the system:

Use the first flat-bottomed holes with a depth of 1/4T, 2/4T and 3/4T and a depth L _above and _below L from the upper and lower surfaces to test the detection capability of the system;

Use the second flat-bottomed holes with a depth of 1/4T, 2/4T and 3/4T and a depth L _above and _below L from the upper and lower surfaces to make a distance-amplitude curve to evaluate the equivalent size of defects at different depths;

Using multiple third flat-bottomed holes in the middle of the thickness of the comparison test block to simulate delamination defects in the steel plate;

Use 80mm×40mm rectangular flat-bottomed grooves with a depth of 1/4T, 2/4T and 3/4T to simulate fold and white spot defects in the sheet;

Use the system to scan the chutes that cover the entire width of the plate and have a depth of 1/4T, 2/4T and 3/4T in the forward direction, and test the system scan coverage and system dynamic detection capabilities and reliability;

2) A plurality of EMAT transducers scan the steel plate to be tested to obtain a scanning waveform; wherein, T is the thickness of the comparison test block, and the _upper L=1.5mm, and _{the lower} L=1.2mm;

3) Automatic assessment:

3.1) Set the first gate, its starting point is located at 1mm from the initial wave, the end point is located at the primary bottom wave 1mm, and its height is the wave height of 60% sensitivity; set the second gate, its starting point is located at 1mm before the primary bottom wave, and its end point is located at the primary bottom wave At 1mm behind the wave, its height is the wave height of 60% sensitivity;

3.2) Carry out automatic detection, automatic recording and automatic evaluation of the EMAT steel plate according to the test results in step 1).

Further, in the above step 1), the diameter of the first flat-bottomed hole is 3mm; the diameter of the second flat-bottomed hole is 6mm; the diameter of the third flat-bottomed hole is 50mm; the size of the rectangular flat-bottomed groove is 80mm×40mm.

Further, the automatic assessment of the above step 3.2) specifically includes: determining the position of the defect in the steel plate through the horizontal scale and vertical scale of the C-scan, and then combining the A-scan to obtain the equivalent value of the defect, and then automatically assessing the defect.

Advantages of the present invention:

1. The electromagnetic ultrasonic detection system and method of the steel plate used for oil and gas transportation of the present invention uses the principle of electromagnetic ultrasonic detection to generate sound waves, and can automatically detect through the selection and arrangement of transducer wave modes, comparison of test block design and manual defect selection and detection gate setting Evaluate the results, realize remote evaluation, realize 100% detection of steel plates for oil and gas transportation, and improve detection speed and detection efficiency.

2. The electromagnetic ultrasonic detection system and method of the steel plate for oil and gas transportation of the present invention utilizes the principle of electromagnetic ultrasonic detection to generate sound waves, which can be automatically displayed through the selection and arrangement of transducer wave modes, comparison of test block design and manual defect selection and detection gate setting Test results and records to achieve permanent storage and traceability of test results, reducing the impact of human factors.

Description of drawings

Figure 1 is a schematic diagram of electromagnetic ultrasonic generation;

Figure 2 is a schematic diagram of SH shear wave used to detect delamination defects;

Fig. 3 is the arrangement and layout diagram of EMAT transducer among the present invention;

Figure 4 is an EMAT transducer with a rotatable magnetic field;

Fig. 5 is the view after the EMAT transducer of Fig. 4 rotatable magnetic field rotates;

Figure 6 is a comparison test block for automatic detection;

Fig. 7 is the A-scan display waveform of steel plate detection;

Fig. 8 is the flat-bottomed hole test blocks of different depths and apertures;

Figure 9 shows the distance-amplitude curves made by using flat-bottomed holes with different depths.

Among them, 1-permanent magnet; 2-AC coil; 3-steel plate for oil and gas transmission to be tested; 4, 6-detection defect gate; 5, 7-monitoring bottom wave gate; 10-EMAT transducer; 11-comparison test block ; T ₁ is the initial wave; B1 is the primary bottom wave; B2 is the secondary bottom wave; d is the diameter of the flat-bottomed hole; T is the thickness of the comparison test block.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

As oil and gas transmission steel pipes are used in land pipelines and deep-sea pipelines (such as the first, second and third pipeline projects of China Petroleum's West-to-East Gas Pipeline Project, the China-Russia East Route Natural Gas Pipeline Project, CNOOC's Nanhai Liwan 3-1 Project and Huangyan Project, etc.) For example, the scanning rate of the automatic ultrasonic detection of the base metal of the steel pipe for submarine pipelines requires 100% scanning, and the scanning rate of the automatic ultrasonic detection of the base metal of the pipe body of the land pipeline requires 50% scanning, while the existing The automatic ultrasound of the piezoelectric chip is greatly limited, such as the number of channels of the detection equipment (currently, the piezoelectric automatic ultrasound can reach 200 channels, while the EMAT can reach 800 channels), and the piezoelectric automatic ultrasound needs a couplant, while EMAT is a non- Coupling detection, etc.

The basic principle of EMAT is to use electromagnetic effects to generate ultrasonic waves. Specifically, a magnet is added outside the energized coil, and the structure of the coil and magnet is changed to generate different types and modes of sound waves. The EMAT transducer 10 is composed of a permanent magnet 1 and an AC coil 2. Magnetic fields, high-frequency electric fields, conductive or magnetically permeable detection materials, and detection materials close to the transducer are the basic elements of EMAT technology. Figure 1 shows the basic principle of electromagnetic ultrasonic generation. The EMAT transducer 10 is placed on the material to be tested, and the alternating current Jo of the ultrasonic frequency is passed into the EMAT coil, and the current will be induced in the conductive material through the coil, which is commonly referred to as Vortex Je. Due to the skin effect, the eddy current is distributed on the surface of the material, and the eddy current generates the Lorentz force f1 under the action of the external magnetic field Bo, which causes the local vibration of the tested material to form elastic waves; the principle of receiving sound waves is the above inverse process. In addition, when the material to be tested has magnetic permeability, the material lattice will also be affected by the magnetostrictive force fms and the magnetizing force fm. The magnetization vector of the magnetic domain in the material will be changed by the influence of the external magnetic field, and the boundary between the magnetic domains will move during the magnetization process, resulting in mechanical deformation, which is the magnetostrictive effect. The magnetostrictive force, magnetizing force, and Lorentz force are coupled with each other, thereby enhancing the excitation effect of the acoustic wave. Among them, Bo is the external magnetic field; Jo is the alternating current; Je is the eddy current; f1 is the Lorentz force; fms is the magnetostrictive force; fm is the magnetizing force.

An electromagnetic ultrasonic automatic detection system for steel plates for oil and gas transportation,

Including a plurality of EMAT transducers 10 and a comparison test block 11;

The plurality of EMAT transducers 10 are divided into a main body transducer group and two groups of side transducer groups, and the two groups of side transducer groups are respectively located on both sides of the main body transducer group; The EMAT transducers 10 of the two groups of side transducer groups are all two rows, and the two rows of EMAT transducers 10 are arranged in a misplaced manner, and the corresponding EMAT transducers 10 of the two rows keep at least 10% overlap; the main body The EMAT transducers at the edge of the transducer group on both sides and the EMAT transducers of the corresponding edge transducer groups maintain at least 10% overlap; the comparison test block 11 includes a steel plate, and the positioning and quantitative processing on the steel plate are manually performed. The reflector, the artificial reflector comprises a plurality of flat-bottomed holes, a plurality of rectangular flat-bottomed grooves and at least one inclined groove.

The mode selection and arrangement of the transducer are as follows:

During the detection process of EMAT, when certain excitation conditions are met, surface waves, SH waves, and LAMB waves will be generated, such as changing the frequency of the excitation electrical signal to meet the following requirements:

f=nC/2Lsinθ (n is any integer),

In the formula, C is the speed of sound, f is the frequency of the electrical signal, and L is 1/2 wavelength.

The sound wave radiates obliquely to the inner side of the workpiece at an inclination angle θ (its amplitude also decreases), that is to say, under the premise that other conditions remain unchanged, as long as the frequency of the electrical signal is changed, the radiation angle θ of the sound wave can be changed, which is Yet another feature of the EMAT transducer 10 . Due to the existence of this feature, the free selection of the wave mode can be realized without changing the transducer.

The EMAT transducer 10 is used to excite the vertically incident SH wave to detect the delamination defect of the steel plate, and to excite the 45° SV wave on the surface of the steel plate to detect the longitudinal and transverse crack defects. Vertically incident SH wave detection of delamination defects will obtain higher longitudinal resolution than longitudinal waves, and electromagnetic ultrasound directly excites and receives ultrasonic waves in the steel plate. Under dynamic conditions, the sound beam angle and sensitivity are more stable, and the detection temperature is greatly expanded. Adapt to range and improve detection speed. The EMAT transducer 10 of the vertically incident SH wave is composed of a vertical magnetic field perpendicular to the steel plate surface and a double helical coil; the 45° SV wave detection probe is composed of a bias magnetic field parallel to the steel plate surface and a two-phase folded coil (or folded coil). Adjust the ultrasound excitation frequency to control the angle of ultrasound according to the spatial frequency of the coil.

For the defects of the steel plate itself, it is generally required to detect only the defects parallel to the surface such as delamination in the steel plate, that is, the vertical method is used for detection, that is, the sound wave should be perpendicular to the surface to be tested. We choose a vertical magnetic field and a double helical coil to design the EMAT transducer 10 shown in FIG. 2 to generate SH waves.

Electromagnetic ultrasonic automatic detection of steel plate adopts the detection form of steel plate conveying through the detection equipment. It mainly consists of a main body transducer group and two sets of edge transducer groups. The main transducer group covers the middle area of the detection steel plate, and the edge detection transducer group detects and tracks the edge area of the steel plate (as shown in Figure 3). Each transducer array adopts two rows of dislocation arrangement, and about 10% repeated coverage is maintained between the transducers, so as to realize 100% coverage scanning of the detection area.

To realize the full-coverage scanning of the steel plate, a large number of transducers are required to scan the entire steel plate. Due to the excessive attraction between many transducers and the steel plate to be tested, it is difficult to separate the transducer from the steel plate. Therefore, the special EMAT transducer (as shown in Fig. 4 and Fig. 5) of the rotatable permanent magnet 1 (magnetic field) has been designed, and the patent document whose publication number is CN107607626A has disclosed the special EMAT transducer, so that the transducer and The steel plate is easy to separate during the detection process, which solves the problem that many transducers are difficult to separate from the steel plate 3 for oil and gas transmission to be tested.

The comparison between the design of test block 11 and the selection of artificial reflectors is as follows:

Some artificial defects are set in the comparison test block 11. The artificial defects are artificial reflectors. The artificial reflectors commonly used in steel plates include flat-bottomed holes, rectangular flat-bottomed grooves and other forms of wire-cut grooves, etc., which are mainly used to simulate delamination, folding, Defects such as white spots. These artificial defects are used to determine the resolution of the upper and lower surfaces of the electromagnetic ultrasonic transducer; adjust the detection ratio and detection range; determine the distance amplitude curve; adjust the detection sensitivity; perform quantitative evaluation of defects; verify scanning coverage and system dynamics Detection capability and reliability, etc.

The external dimensions of the designed comparison test block 11 should be designed as steel plates of 6000mm×3700mm×33mm (length×width×thickness) according to the maximum specification of oil and gas transmission steel pipes Φ1219×33mm, and the artificial defects in the comparison test block 11 should be Φ3mm/Φ6mm/Φ50mm Flat-bottomed holes with different depths, rectangular flat-bottomed grooves with different depths of 40mm×80mm, and inclined grooves with a width of 6mm and different depths covering the width of the plate. Figure 6 is a comparison test block 11 of the designed steel plate for oil and gas transportation and a diagram of artificial defects, the details are as follows:

a. In the middle of the comparison test block 11, the design aperture is 3mm, and the buried depth is 1.5mm (resolution of the upper surface of the electromagnetic ultrasonic transducer), 8.25mm, 16.5mm, 24.75mm and 31.8mm (resolution of the lower surface of the electromagnetic ultrasonic transducer). 1 set of flat-bottomed holes, used to test the detection system and the detection capability of the electromagnetic ultrasonic transducer;

b. The distance from the periphery of the comparison test block 11 to the edge of the plate is 25mm (mainly depends on the width of the electromagnetic ultrasonic transducer, the width of the electromagnetic ultrasonic transducer is 50mm) and the design aperture of the middle part of the plate is 6mm, and the burial depth is 1.5mm (electromagnetic Ultrasonic transducer upper surface resolution), 8.25mm, 16.5mm, 24.75mm and 31.8mm (electromagnetic ultrasonic transducer lower surface resolution) 5 groups of flat-bottomed holes are used to make distance-amplitude curves and evaluate defects at different depths Equivalent size;

c. In the middle of the comparison test block 11, four flat-bottomed holes with a diameter of 50mm and a buried depth of 16.5mm are designed to simulate delamination defects in the plate;

d. In the middle of the comparison test block 11, design width×length: 40mm×80mm, and 2 sets of rectangular flat-bottomed grooves with burial depths of 8.25mm, 16.5mm and 24.75mm, respectively, to simulate defects such as folding and white spots in the plate;

e. In the comparison test block 11, design a chute with a width of 6 mm in the width direction of the plate, buried depths of 8.25 mm, 16.5 mm and 24.75 mm, and a chute whose length runs obliquely through the width of the plate for testing the scanning of the electromagnetic ultrasonic transducer Coverage and system dynamic detection capabilities and reliability.

f. In the designed comparison test block 11, a dotted line located in the middle of the length of the comparison test block 11 can cut the comparison test block 11 into 2 pieces along the dotted line, mainly for the convenience of transportation or processing of artificial defects. The comparison test blocks 11 can be welded together.

In Figure 6:

1. A1～A5 are Ф6mm flat bottom holes, A6 are Ф3mm flat bottom holes, the buried depth is 1.2mm; B1～B5 are Ф6mm flat bottom holes, B6 are Ф3mm flat bottom holes, and the buried depth is 1/4T; C1～C5 are Ф6mm flat bottom holes , C6 is a Ф3mm flat-bottomed hole, with a burial depth of 1/2T; D1 to D5 are Ф6mm flat-bottomed holes, D6 is a Ф3mm flat-bottomed hole, with a burial depth of 3/4T; E1 to E5 are Ф6mm flat-bottomed holes, and E6 is a Ф3mm flat-bottomed hole, buried The depth is 1.5mm.

2. F is 80mm×40mm×1/4T rectangular flat-bottomed tank; G is 80mm×40mm×1/2T rectangular flat-bottomed tank; H is 80mm×40mm×3/4T rectangular flat-bottomed tank.

3. I is a Φ50mm flat-bottomed hole with a buried depth of 1/2T.

4. JKL and MNO are inclined grooves, the width of JKL is 6mm, the depth of JK is 1/4T, the length of JK is 2/3JKL, the depth of KL is 2/4T, and the length of KL is 1/3JKL; the width of MNO is 6mm, and the depth of MN is 2/4T, MN length is 1/3MNO, NO depth is 3/4T, NO length is 2/3MNO.

5. Other artificial defects can also be processed on the comparison test block 11.

6. The comparison test block can be divided into two parts, processed and then welded together, so as to facilitate processing or transportation.

A detection method for the above-mentioned steel plate electromagnetic ultrasonic automatic detection system for oil and gas transportation, characterized in that it includes the following steps:

1) Scan the comparison test block to test the detection capability of the system (as shown in Figure 8 and Figure 9):

Use the first flat-bottomed holes with a depth of 1/4T, 2/4T and 3/4T and a depth L _above and _below L from the upper and lower surfaces to test the detection capability of the system;

Use the second flat-bottomed holes with a depth of 1/4T, 2/4T and 3/4T and a depth L _above and _below L from the upper and lower surfaces to make a distance-amplitude curve to evaluate the equivalent size of defects at different depths;

Using a plurality of third flat-bottomed holes in the middle of the comparison test block 11 to simulate delamination defects in the steel plate;

Use 80mm×40mm rectangular flat-bottomed grooves with a depth of 1/4T, 2/4T and 3/4T to simulate fold and white spot defects in the sheet;

Use the system to scan the chutes that cover the entire width of the plate in the forward direction and have a depth of 1/4T, 2/4T, and 3/4T to test the system scan coverage and system dynamic detection capabilities and reliability; where T is the comparative test Thickness of the block, _above L = 1.5mm, _under L = 1.2mm;

2) Multiple EMAT transducers 10 scan the steel plate to be tested to obtain a scanning waveform;

3) Automatic assessment:

3.1) For the setting of double gates, the waveform is shown in Figure 7 during the steel plate EMAT inspection, showing the defect waveform and the bottom wave. Using the detection defect gate 4, the detection defect gate 6, the monitoring bottom wave gate 5, and the monitoring bottom wave gate 7 Monitoring the defect wave and bottom wave can realize the automatic recording function. Usually, the gate width of the primary gate defect wave is set between the initial wave and the primary bottom wave, the starting point of the gate is about 1 mm after the initial wave, and the gate end is about 1 mm before the primary bottom wave. The height of the gate is set at the wave height of 60% sensitivity; the starting point of the bottom wave width of the secondary gate is set at about 1 mm before the primary bottom wave, and the end point of the gate is set at about 1 mm behind the primary bottom wave, so that double gates are set.

3.2) Carry out automatic detection, automatic recording and automatic evaluation of the EMAT steel plate according to the test results in step 1).

Through the above EMAT generation, wave mode selection, transducer arrangement, design of comparison test block 11, detection gate setting and automatic evaluation system research, a dynamic comparison test block 11 for automatic detection as shown in Figure 6 is produced for verification, and the results of scanning are detected. The comparison test block 11 automatically records the scan chart, which has a good correspondence with the artificial defects in the designed dynamic comparison test block 11 for automatic detection, and achieves the expected effect. The C-scan can determine the position of the defect in the steel plate through the horizontal scale and the vertical scale, display the shape and distribution of the defect, and then combine with the A-scan to obtain the equivalent value of the defect, so as to automatically evaluate the defect.

Claims (9)

1. a kind of oil-gas transportation steel plate electromagnetic acoustic automatic checkout system, it is characterised in that:

Including multiple EMAT energy converters (10) and reference block (11)；

The multiple EMAT energy converter (10) is divided into main body energy converter group and two groups of edge energy converter groups, two groups of edge energy converter groups It is located at the two sides of main body energy converter group；The EMAT energy converter (10) of main body energy converter group and two groups of edge energy converter groups is Two rows, two rows of EMAT energy converter (10) Heterogeneous Permutations, and two rows of corresponding EMAT energy converters (10) keep at least 10% weight It closes；The most marginal EMAT energy converter in main body energy converter group two sides is kept with the EMAT energy converter of corresponding edge energy converter group At least 10% coincidence；

The reference block (11) includes steel plate, positions on steel plate, quantitatively processes artificial reflector, the artificial reflector includes Multiple flat-bottom holes, multiple rectangle flat-bottom slots and at least one skewed slot.

2. a kind of oil-gas transportation according to claim 1 steel plate electromagnetic acoustic automatic checkout system, it is characterised in that: institute It states EMAT energy converter (10) and chooses vertical magnetic field, double-spiral coil, the EMAT energy converter for generating SH wave.

3. a kind of oil-gas transportation according to claim 1 or 2 steel plate electromagnetic acoustic automatic checkout system, feature exist In: reference block (11) outer dimension is identical with steel plate (3) size as oil-gas transportation to be measured.

4. a kind of oil-gas transportation according to claim 1 or 2 steel plate electromagnetic acoustic automatic checkout system, feature exist In: the reference block (11) is welded using two blocks of steel plates.

5. a kind of oil-gas transportation according to claim 1 steel plate electromagnetic acoustic automatic checkout system, it is characterised in that: institute It states multiple flat-bottom holes and is separately positioned on reference block (11) middle part and surrounding edge at sheet edge 25mm；It is arranged in plate Flat-bottom hole in the middle part of material is three groups, one group of aperture 3mm, buried depth be respectively 1.5mm, 8.25mm, 16.5mm, 24.75mm and 31.8mm；

Aperture is one group of 6mm, and buried depth is respectively the flat of 1.5mm, 8.25mm, 16.5mm, 24.75mm and 31.8mm Hole；Aperture is one group of 50mm, buried depth 16.5mm；

The multiple rectangle flat-bottom slot setting is in the middle part of reference block (11), width × length: 40mm × 80mm, buried depth point Not Wei 8.25mm, 16.5mm and 24.75mm, laterally and longitudinally respectively setting half；

The skewed slot setting is in the middle part of reference block (11) and perforation plate width direction, width 6mm, buried depth are respectively 8.25mm, 16.5mm and 24.75mm.

6. a kind of oil-gas transportation according to claim 5 steel plate electromagnetic acoustic automatic checkout system, it is characterised in that: institute The quantity for stating the flat-bottom hole that aperture is 50mm is 4.

7. a kind of oil-gas transportation steel plate electromagnetic acoustic automatic testing method, which comprises the following steps:

1) reference block is scanned, the detectability of test macro:

It is 1/4T, 2/4T and 3/4T using depth and distinguishes L apart from upper and lower surface depth_OnAnd L_UnderThe first flat-bottom hole, test The detectability of system；

It is 1/4T, 2/4T and 3/4T using depth and distinguishes L apart from upper and lower surface depth_OnAnd L_UnderThe second flat-bottom hole production away from From amplitude curve, the equivalent size of different depth defect is evaluated；

Using third flat-bottom holes multiple in the middle part of reference block (11), lamination defect in steel plate is simulated；

Using the rectangle flat-bottom slot for 80mm × 40mm that depth is 1/4T, 2/4T and 3/4T, folding in plate is simulated, white point lacks It falls into；

Using entire strip width and depth is covered in system scanning direction of advance as the skewed slot of 1/4T, 2/4T and 3/4T, test System scanning coverage rate and system dynamic detection ability and reliability；Wherein, T is the thickness of reference block, the L_On= 1.5mm,L_Under=1.2mm；

2) multiple EMAT energy converters (10) are scanned steel plate to be measured, obtain sweep waveform figure；

3) automatic evaluation:

3.1) the first gate is set, and starting point is located at beginning wave 1mm, and terminal is located at primary bottom wave 1mm, and height is sensitivity 60% wave height；Second gate is set, and starting point is located at primary bottom wavefront 1mm, and terminal is located at after primary bottom wave at 1mm, high Degree is 60% wave height of sensitivity；

3.2) EMAT steel plate is carried out according to the test result in step 1) to detect, automatically record and automatic evaluation automatically.

8. a kind of oil-gas transportation steel plate electromagnetic acoustic automatic testing method according to claim 7, it is characterised in that: step 1) in, the diameter of the first flat-bottom hole is 3mm；The diameter of second flat-bottom hole is 6mm；The diameter of third flat-bottom hole is 50mm；Rectangle Flat-bottom slot is having a size of 80mm × 40mm.

9. a kind of oil-gas transportation steel plate electromagnetic acoustic automatic testing method according to claim 8, it is characterised in that: step 3.2) automatic evaluation specifically: defective locations in steel plate are determined by the horizontal scale and vertical scale of C-scan, in conjunction with A Scanning obtains Defect Equivalent value, carries out automatic evaluation to defect.