Ultrasonic detection method for butt-joint circumferential weld of austenitic stainless steel pipe

Abstract

The invention relates to the technical field of nondestructive detection of welding seams, in particular to an ultrasonic detection method for butt-joint circumferential welding seams of austenitic stainless steel pipes, which comprises the following steps: S1, determining the structure of a workpiece to be detected; s2, a focusing longitudinal wave angle probe with the corresponding focusing depth is selected according to the object workpiece; processing the probe structure into a structure matched with the circumferential radian of the object workpiece; s3, calibrating the selected focusing longitudinal wave angle probe by adopting a standard test block with a corresponding calibration surface; s4, carrying out ultrasonic detection curve adjustment on the calibrated focusing longitudinal wave angle probe on a reference block; s5, performing ultrasonic detection curve verification on the adjusted focusing longitudinal wave angle probe on a verification test block; and S6, the ultrasonic detection equipment which is debugged to be qualified is used for circumferential weld detection of the object workpiece. According to the invention, the ultrasonic nondestructive testing technology is effectively adapted to the detection of the circumferential weld structure of the corresponding austenitic stainless steel pipeline, and the technical problem that the circumferential weld of the austenitic stainless steel pipeline is detected by the ultrasonic nondestructive testing technology is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of weld nondestructive testing, and particularly relates to an ultrasonic testing method for butt joint girth welds of austenitic stainless steel pipes. BACKGROUND

[0002] In the pipeline structure of system equipment, in order to adapt to the technical requirements of the design length and the structural form change, it is a common practice to sequentially weld multiple pipelines. In order to ensure the welding quality between the pipelines, it is also necessary to perform nondestructive testing on the girth welds of the pipelines, which also includes the high-pressure air system pipeline for wind tunnel tests.

[0003] In order to ensure the structural rigidity and reduce the vibration of the high-pressure air system pipeline for wind tunnel tests, the austenitic stainless steel of 06Cr19Ni10 material is designed to be made. Therefore, the aforementioned austenitic stainless steel pipeline has a girth weld structure, which is usually formed by argon arc welding. For the nondestructive testing of the butt joint girth welds of the aforementioned austenitic stainless steel pipeline, the current main method is to use the conventional radiographic testing method (i.e., the double-wall radiographic testing method). However, the conventional radiographic testing method is limited to pipeline structures with a wall thickness of ≤20 mm. When the wall thickness of the pipeline is >20 mm, the radiographic testing method cannot be used due to the serious attenuation of the X-ray energy.

[0004] In order to meet different technical requirements of wind tunnel tests, the current design specifications (pipe diameter and wall thickness) of the high-pressure air system pipeline have Φ168mm*28mm, Φ273mm*45mm, and 323mm*55mm. As can be seen, the wall thickness of the aforementioned austenitic stainless steel pipeline structure is obviously greater than 20 mm, and the conventional radiographic testing method cannot be used for nondestructive testing of the girth weld structure thereof.

[0005] The ultrasonic nondestructive testing technology has the technical characteristics of low detection cost, simple operation, high sensitivity, high safety, and low requirement for pipeline wall thickness structure, and can be used for nondestructive testing of the girth welds of the aforementioned large pipeline wall thickness. However, due to the coarse grain structure of the austenitic stainless steel itself and the characteristics of the girth weld curved surface structure, when the ultrasonic nondestructive testing technology is used for the detection of the butt joint girth welds of the aforementioned austenitic stainless steel pipeline, the following main technical problems may exist: 1. During the ultrasonic testing, the ultrasonic wave needs to pass through the austenitic stainless steel pipe to reach the weld. Due to the coarse grain structure of the austenitic stainless steel, the attenuation and scattering of the ultrasonic wave in the austenitic stainless steel are relatively large, and a regular waveform cannot be formed to achieve detection. 2. The weld of the above-mentioned austenitic stainless steel pipeline is a girth weld structure, which is formed in the circumferential direction of the pipeline and has a curved track, so that the probe moving area of the ultrasonic testing is a circular arc track, and the flat head structure of the probe has the phenomenon of incomplete fitting and poor coupling on the outer periphery of the pipeline, which directly reduces the energy of the emitted wave.

[0006] Therefore, the above technical problems directly restrict the application of ultrasonic non-destructive testing technology to the above-mentioned austenitic stainless steel pipeline, especially the pipeline with a wall thickness greater than 20 mm. SUMMARY

[0007] The technical purpose of the present application is to provide an austenitic stainless steel pipe butt girth weld detection method based on ultrasonic non-destructive testing technology to effectively solve the technical problem that the above-mentioned ultrasonic non-destructive testing technology is difficult to apply to the above-mentioned austenitic stainless steel pipeline, especially the pipeline with a wall thickness greater than 20 mm, in view of the particularity of the above-mentioned austenitic stainless steel pipeline and ultrasonic non-destructive testing technology and the shortcomings of the prior art.

[0008] The technical purpose of the present application is achieved by the following technical scheme: an ultrasonic detection method for the girth weld of an austenitic stainless steel pipe, the ultrasonic detection method comprising the following process steps: S1. Determine the structure of the detected workpiece; S2. Select a focused longitudinal wave oblique probe with a corresponding focal depth according to the structure of the workpiece; Process the probe structure of the focused longitudinal wave oblique probe to match the structure of the girth arc of the workpiece; S3. Calibrate the selected focused longitudinal wave oblique probe and ultrasonic non-destructive testing equipment using a standard test block with a corresponding calibration surface; S4. Adjust the ultrasonic testing curve of the calibrated focused longitudinal wave oblique probe and ultrasonic non-destructive testing equipment on a comparison test block; S5. Verify the ultrasonic testing curve of the adjusted focused longitudinal wave oblique probe and ultrasonic non-destructive testing equipment on a verification test block; S6. Use the debugged ultrasonic non-destructive testing equipment for girth weld detection of the workpiece.

[0009] Further, in step S1, the workpiece is a high-pressure air system pipeline for wind tunnel testing, which is made of 06Cr19Ni10 material, and the butt girth weld is an argon arc welding structure.

[0010] Further, in step S2, the selection of the focused longitudinal wave oblique probe is based on the wall thickness structure of the workpiece, and at least one focused longitudinal wave oblique probe is selected according to the effective focal depth range of the focused longitudinal wave oblique probe; When selecting multiple focused longitudinal wave angle probes, the selected probes should be scanned in sections during testing, with at least 15% overlap between different sections.

[0011] Furthermore, in the structure of the object workpiece, the specifications of pipe diameter and wall thickness are divided into Φ168mm*28mm, Φ273mm*45mm or 323mm*55mm; Correspondingly, for a workpiece with dimensions of Φ168mm*28mm, the effective focusing depth of the selected focusing longitudinal wave angle probe is 20mm; For a workpiece with a specification of Φ273mm*45mm, the effective focusing depths of the selected focused longitudinal wave angle probes are 20mm and 40mm respectively. During ultrasonic testing, the two types of focused longitudinal wave angle probes are scanned in sections, and there is at least 15% overlap between different sections. For a workpiece with dimensions of 323mm*55mm, the effective focusing depths of the selected focused longitudinal wave angle probes are 15mm, 30mm and 50mm respectively. During ultrasonic testing, the three focused longitudinal wave angle probes are scanned in sections, and there is at least 15% overlap between different sections.

[0012] Furthermore, the effective focusing depth range of the selected focusing longitudinal wave angle probe used on the workpiece is between 15 mm and 50 mm; Correspondingly, in step S3, the standard test block is made of the same material as the object workpiece. The standard test block has a working surface one, and a first calibration surface, a second calibration surface and a third calibration surface that are respectively distributed in a curved structure based on the working surface one. The working surface is a curved surface structure that matches the curvature structure of the focused longitudinal wave angle probe. The first calibration surface is used to calibrate the focusing longitudinal wave angle probe with a focusing depth of 15 mm and a focusing depth of 20 mm. The second calibration surface is used to calibrate the focusing longitudinal wave angle probes with focusing depths of 30 mm and 40 mm; The third calibration surface is used to calibrate a focusing longitudinal wave angle probe with a focusing depth of 50 mm.

[0013] Furthermore, the curvature of the working surface is formed along the axial direction of the standard test block; The first calibration surface, the second calibration surface, and the third calibration surface are arranged on the same side of the working surface. Furthermore, the first calibration surface is located on one side, while the second and third calibration surfaces are arranged in a stepped structure on the same side.

[0014] Furthermore, in step S4, the comparison test block is manufactured using the same process as the target workpiece; The contrast test block has a working surface two for detection work by the focused longitudinal wave oblique probe, and the working surface two is a curved surface structure matching the arc structure of the focused longitudinal wave oblique probe. A plurality of defect simulation holes one are arranged at the width center of the girth weld one of the contrast test block and are arranged at intervals along the weld height direction.

[0015] Further, in step S5, the verification test block is made by the same process as the object workpiece. The verification test block has a working surface three for detection work by the focused longitudinal wave oblique probe, and the working surface three is a curved surface structure matching the arc structure of the focused longitudinal wave oblique probe. A plurality of defect simulation holes two are arranged at the one side groove of the girth weld two of the verification test block and are arranged at intervals along the weld height direction.

[0016] Further, in step S6, the ultrasonic nondestructive testing equipment detects the girth weld of the object workpiece, including the following procedures: The detection surface of the object workpiece is cleaned to remove impurities including paint, welding spatter, iron filings and oil stains. The detection surface of the object workpiece is processed to be flat, the weld reinforcement is removed and is flush with the adjacent base material, the gap between the detection surface and the probe wedge or protective film is ≤0.5mm, and the roughness Ra of the detection surface is ≤25μm.

[0017] The above technical measures are aimed at the particularity of the austenitic stainless steel pipeline and the ultrasonic nondestructive testing technology, the focused longitudinal wave oblique probe with a suitable focusing depth is selected based on the structure of the austenitic stainless steel pipeline to be detected, the probe structure is processed into a curved surface structure matching the circumferential arc of the object workpiece, the selected focused longitudinal wave oblique probe is calibrated by the corresponding standard test block, adjusted by the corresponding contrast test block, and verified by the corresponding verification test block, so that the selected and targeted focused longitudinal wave oblique probe effectively adapts to the austenitic stainless steel pipeline to be detected, i.e. effectively solves the technical problem of application adaptation of the ultrasonic nondestructive testing technology to the austenitic stainless steel pipeline, especially the pipeline with a wall thickness greater than 20mm, so that the ultrasonic nondestructive testing technology effectively adapts to the austenitic stainless steel pipeline with coarse grain structure and girth weld curved surface structure, especially the austenitic stainless steel pipeline with a wall thickness greater than 20mm.

[0018] That is to say, the above technical measures neither change the ultrasonic nondestructive testing technology itself, nor change the austenitic stainless steel pipe girth weld structure itself, but through the targeted selection of the focused longitudinal wave oblique probe and the probe curved surface processing, calibration processing, comparison processing and verification processing, the ultrasonic nondestructive testing technology is effectively adapted to the girth weld structure detection of the corresponding austenitic stainless steel pipe, and the technical difficulties of the austenitic stainless steel pipe girth weld detection by the ultrasonic nondestructive testing technology are effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structural schematic view of a standard test block of the present application.

[0020] Figure 2 It is a left view of Figure 1 .

[0021] Figure 3 It is a structural schematic view of a comparison test block of the present application.

[0022] Figure 4 It is a left view of Figure 3 .

[0023] Figure 5 It is a structural schematic view of a verification test block of the present application.

[0024] Figure 6 It is a left view of Figure 5 .

[0025] Code meaning in the figure: 1-standard test block; 11-operation surface one; 12-first calibration surface; 13-second calibration surface; 14-third calibration surface; 2-comparison test block; 21-girth weld one; 22-defect simulation hole one; 23-operation surface two; 3-verification test block; 31-girth weld two; 32-defect simulation hole two; 33-operation surface three. DETAILED DESCRIPTION

[0026] The present application relates to the field of weld nondestructive testing, in particular to an ultrasonic detection method for butt girth welds of austenitic stainless steel pipes, and the main technical solution of the present application will be described in detail below in combination with multiple embodiments. Among them, embodiment 1 in combination with the drawings of the specification, i.e. Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 clearly and specifically explain the technical solution content of the present application; although other embodiments are not separately drawn, the main structure can still refer to the drawings of embodiment 1.

[0027] It is particularly pointed out that the drawings of the present application are schematic, which have simplified unnecessary details in order to make the technical purpose of the present application clear, so as to avoid obscuring the technical scheme contributed by the present application to the prior art. In addition, the expressions such as "about", "substantially" and the like with respect to quantity or matching relationship in the following mean that the existence of reasonable assembly error, machining error and the like is allowed, and not the absolute quantity or matching relationship expressed literally.

[0028] Embodiment 1 The present application is an ultrasonic testing method for butt joint weld of austenitic stainless steel pipe, which is applicable to the object workpiece of high-pressure air system pipeline for wind tunnel test, which is made of 06Cr19Ni10 material, and the specification of pipe diameter and wall thickness is Φ323mm*55mm, and the butt joint weld is an argon arc welding structure.

[0029] The ultrasonic testing method of the present application specifically includes the following process steps: S1. Based on the pipeline structure as above, the structure of the object workpiece to be detected is determined, i.e. the specification of pipe diameter and wall thickness; S2. Based on the structure of the object workpiece, a focused longitudinal wave oblique probe is selected; For the structure with a wall thickness of 55mm, it is difficult for a single focused longitudinal wave oblique probe to cover the focus, so in combination with the effective focus depth, incident angle performance parameters and the like of the focused longitudinal wave oblique probe, the detection of the wall thickness of 55mm is divided into three groups of predicted detection depth ranges of 0-20mm, 16-35mm and 28-55mm, so as to respectively select a focused longitudinal wave oblique probe with an effective focus depth of 15mm, a focused longitudinal wave oblique probe with an effective focus depth of 30mm and a focused longitudinal wave oblique probe with an effective focus depth of 50mm, the model of the selected focused longitudinal wave oblique probe with an effective focus depth of 15mm is specifically 2MHZ 10x16x2LA60FG15, the model of the selected focused longitudinal wave oblique probe with an effective focus depth of 30mm is specifically 2MHZ 10x16x2LA45FG30, and the model of the selected focused longitudinal wave oblique probe with an effective focus depth of 30mm is specifically 2MHZ 10x16x2LA45FG50; For the selection of the above three kinds of focused longitudinal wave oblique probes, a detection scheme that is matched and complementary to each other is formed, so when detecting scanning (including the following calibration process, adjustment process and verification process), the selected three kinds of focused longitudinal wave oblique probes should be scanned in different zones, and there is about 20% overlap between different zones; In order to adapt to the curvature of the object workpiece pipe diameter Φ323mm, and be conducive to maintaining high energy of the emitted wave of ultrasonic wave, the probe structures of the selected three kinds of focused longitudinal wave oblique probes are respectively processed into structures matching the circumferential curvature of the object workpiece, i.e. the structure of each probe adopts a wafer curvature of Φ323mm; S3. Adopting the likeFigure 1 and Figure 2 The standard test block 1 shown in the drawings has multiple corresponding calibration surfaces, and is used for angle calibration of the selected focused longitudinal wave oblique probe and the ultrasonic nondestructive testing equipment. The standard test block 1 mainly calibrates the parameters of sound velocity, front, and K value. Referring to Figure 1 and Figure 2 The standard test block 1 is made of the same material as the object workpiece, and has a working surface 1 at the top, and a first calibration surface 11, a second calibration surface 12, and a third calibration surface 13 arranged at the bottom of the working surface 1 and distributed in a curved surface structure, i.e., the first calibration surface 11, the second calibration surface 12, and the third calibration surface 13 are arranged on the same side of the working surface 1, and the first calibration surface 11 is alone on one side, and the second calibration surface 12 and the third calibration surface 13 are on the same side and arranged in a stepped structure. The working surface 1 is a curved surface structure matching the arc structure of the focused longitudinal wave oblique probe (i.e., wafer arc Φ323mm), which has good fit with the wafer arc of the focused longitudinal wave oblique probe, and is beneficial to maintaining high energy of the emitted wave of the ultrasonic wave. The curved surface arc of the working surface 1 is formed along the axial direction of the standard test block 1 (relative to the circular arc axial direction of each calibration surface) to meet the angle calibration of the focused longitudinal wave oblique probe through the corresponding calibration surface. The first calibration surface 11 is used for calibrating the focused longitudinal wave oblique probe with a focus depth of 15mm, the second calibration surface 12 is used for calibrating the focused longitudinal wave oblique probe with a focus depth of 30mm, and the third calibration surface 13 is used for calibrating the focused longitudinal wave oblique probe with a focus depth of 50mm. It can be seen that the aforementioned standard test block 1 can simultaneously satisfy the calibration of the focused longitudinal wave oblique probe with different focus depths, and has good flexibility. S4. The comparative test block 2 shown in Figure 3 and Figure 4 is used to cover defects of different depth positions of the ring weld, and the calibrated focused longitudinal wave oblique probe and the ultrasonic nondestructive testing equipment are used for ultrasonic testing curve (i.e., DAC curve) adjustment on the comparative test block 2 to adjust the sensitivity. Referring to Figure 3 and Figure 4 The comparative test block 2 is made of the same process as the object workpiece, including the same material, the same arc structure, the same wall thickness, the same ring weld structure, the same welding process, etc. The comparative test block 2 has a working surface 2 for detection work of the selected focused longitudinal wave oblique probe, and the working surface 2 is a curved surface structure matching the arc structure of the focused longitudinal wave oblique probe (i.e., wafer arc Φ323mm). At the center of the width of the circumferential weld 21 of the comparison test block 2, there are multiple defect simulation holes 22 arranged at basically regular intervals along the height direction of the weld. For example, the defect simulation hole at height h1 is about 5 mm above the working surface 23, the defect simulation hole at height h2 is about 15 mm above the working surface 23, the defect simulation hole at height h3 is about 25 mm above the working surface 23, the defect simulation hole at height h4 is about 35 mm above the working surface 23, and the defect simulation hole at height h5 is about 50 mm above the working surface 23. These defect simulation holes basically cover the defects at different heights in the height direction of the circumferential weld 21, and also basically cover the focusing depth range of the three focusing longitudinal wave angle probes. Each defect simulation hole is formed in the comparison test block 2 with a transverse through hole structure. The weld reinforcement at the top surface of the aforementioned circumferential weld 21 was ground flat by machining to make it flush with the adjacent base material; The length L of the aforementioned comparative test block 2 is approximately 3P, where P = 2KT, K is the tangent of the probe angle, and T is the pipe wall thickness; S5. Adopt as follows Figure 5 and Figure 6 The verification test block 3 shown is used to verify the ultrasonic test curves of each adjusted focused longitudinal wave angle probe and ultrasonic non-destructive testing equipment on the verification test block 3, so as to verify the accuracy of the test curves. See Figure 5 and Figure 6 As shown, the verification test block 3 is manufactured using the same process as the object workpiece, including the same material, the same curvature structure, the same wall thickness, and the same welding process. The verification test block 3 has a working surface 33 for the selected focused longitudinal wave angle probe to perform testing operations. The working surface 33 is a curved surface structure that matches the arc structure of the focused longitudinal wave angle probe (i.e., the wafer arc Φ323mm). On one side of the bevel of the second circumferential weld 31 of the verification test block 3, there are multiple defect simulation holes 32 arranged at a basically regular interval along the height direction of the weld. For example, in the figure, the defect simulation hole at height h1 is about 5 mm away from the working surface 33, the defect simulation hole at height h2 is about 15 mm away from the working surface 33, the defect simulation hole at height h3 is about 25 mm away from the working surface 33, the defect simulation hole at height h4 is about 35 mm away from the working surface 33, and the defect simulation hole at height h5 is about 50 mm away from the working surface 33. These defect simulation holes basically cover the defects at different heights in the height direction of the second circumferential weld 31, and also basically cover the focusing depth range of the three focusing longitudinal wave angle probes. Each defect simulation hole is formed in the verification test block 3 with a transverse through hole structure. The length L of the above-mentioned verification block 3 is about 3P, wherein P=2KT, K is the tangent value of the probe angle, and T is the pipe wall thickness. S6. The debug qualified ultrasonic detection device is used for detecting the girth weld of the object workpiece, and specifically includes the following steps: The detection surface of the object workpiece is cleaned to remove various impurities including paint, welding spatter, iron filings and oil stains; The detection surface of the object workpiece is polished to remove the weld reinforcement and make it flush with the adjacent base material, so that the gap between the detection surface and the probe wedge or protective film is ≤0.5mm, and the roughness Ra of the detection surface is ≤25μm; When detecting longitudinal defects, the focused longitudinal wave oblique probe should be placed vertically on the detection surface, and the range of forward and backward movement of the focused longitudinal wave oblique probe should ensure that all cross sections of the welded joint are scanned; In order to observe the dynamic waveform of the defect and distinguish the defect signal or false defect signal, and determine the position, direction and shape of the defect, the basic scanning methods such as forward and backward and left and right can be used.

[0030] The above ultrasonic detection method is repeatedly verified on the object workpiece, that is, after the ultrasonic nondestructive testing is completed, the object workpiece is gas planed according to the detection results, and it is found that the defects and positioning obtained in the detection process are consistent with the defects and positioning found by gas planing. The above ultrasonic detection method has good detection accuracy on the object workpiece.

[0031] Example 2 The present application is an ultrasonic detection method for butt girth welds of austenitic stainless steel pipes. The object workpiece suitable for the detection method is a high-pressure air system pipe for wind tunnel testing, which is made of 06Cr19Ni10 material, has a pipe diameter and wall thickness specification of Φ273mm*45mm, and has an argon arc welding structure for butt girth welds.

[0032] The ultrasonic detection method of the present application specifically includes the following process steps: S1. Based on the above pipe structure, the structure of the object workpiece to be detected is determined, that is, the pipe diameter and wall thickness specification; S2. Based on the structure of the object workpiece, a focused longitudinal wave oblique probe is selected; For the structure with a wall thickness of 45 mm, it is difficult for a single focused longitudinal wave oblique probe to cover the focus, and therefore, in combination with the effective focus depth, the incident angle performance parameters and the like of the focused longitudinal wave oblique probe, the detection of the wall thickness of 45 mm is divided into two groups of predicted detection depth ranges of 0-28 mm and 22-45 mm, and thus a focused longitudinal wave oblique probe with an effective focus depth of 20 mm and a focused longitudinal wave oblique probe with an effective focus depth of 40 mm are selected, and the model of the selected focused longitudinal wave oblique probe with an effective focus depth of 20 mm is 2MHZ 10x16x2LA60FG20, and the model of the selected focused longitudinal wave oblique probe with an effective focus depth of 40 mm is 2MHZ 10x16x2LA45FG40; For the selection of the above two kinds of focused longitudinal wave oblique probes, a detection scheme that cooperates and complements each other is formed, and therefore, when detection scanning (including the following calibration processing, adjustment processing and verification processing) is performed, the selected two kinds of focused longitudinal wave oblique probes should be scanned in different zones, and there is about 20% overlap between different zones; In order to adapt to the curvature of the object workpiece with a pipe diameter of Φ273 mm and be beneficial to maintaining high energy of the emitted wave of the ultrasonic wave, the probe structures of the selected two kinds of focused longitudinal wave oblique probes are respectively processed into structures that match the circumferential curvature of the object workpiece, that is, the structures of the probes adopt a wafer curvature of Φ273 mm; S3. A standard test block with a plurality of corresponding calibration surfaces as shown in Figure 1 and Figure 2 is used to perform angle calibration processing on the selected focused longitudinal wave oblique probe and the ultrasonic nondestructive testing equipment, and the main parameters calibrated by the standard test block are sound velocity, front, and K value; The standard test block is made of the same material as the object workpiece, has a working surface one at the top, and has a first calibration surface, a second calibration surface and a third calibration surface arranged at the bottom of the working surface one and respectively distributed in a curved surface structure, that is, the first calibration surface, the second calibration surface and the third calibration surface are arranged on the same side of the working surface one, and the first calibration surface is alone on one side, and the second calibration surface and the third calibration surface are on the same side and arranged in a stepped structure; The working surface one is a curved surface structure that matches the curvature structure of the focused longitudinal wave oblique probe (i.e. wafer curvature Φ273 mm), which has good fit with the wafer curvature of the above-mentioned focused longitudinal wave oblique probe, and is beneficial to maintaining high energy of the emitted wave of the ultrasonic wave, and the curved surface curvature of the working surface one is formed along the axial direction of the standard test block (relative to the circular arc axial direction of each calibration surface) to meet the angle calibration of the focused longitudinal wave oblique probe through the corresponding calibration surface; The first calibration surface is used for calibrating a focused longitudinal wave angle probe with a focus depth of 20 mm, the second calibration surface is used for calibrating a focused longitudinal wave angle probe with a focus depth of 40 mm, and the third calibration surface is used for calibrating a focused longitudinal wave angle probe with a focus depth of 50 mm (not involved in the embodiment, and can be idle). Therefore, it can be seen that the foregoing standard test block can simultaneously satisfy the calibration of focused longitudinal wave angle probes with different focus depths, and has good flexibility. S4. Adopting the comparative test block shown in Figure 3 and Figure 4 for covering defects at different depth positions of the girth weld, the ultrasonic testing curve (i.e., DAC curve) of each calibrated focused longitudinal wave angle probe and ultrasonic nondestructive testing equipment is adjusted on the comparative test block to adjust the sensitivity thereof. The comparative test block is formed by the same process as the object workpiece, including the same material, the same curvature structure, the same wall thickness, the same girth weld structure, the same welding process, etc. The comparative test block has a second working surface for detection work of the selected focused longitudinal wave angle probe, and the second working surface is a curved surface structure matching the curvature structure (i.e., wafer curvature Φ273 mm) of the focused longitudinal wave angle probe. A plurality of defect simulation holes one are arranged at a regular interval along the height direction of the girth weld one at the center of the width of the girth weld one, for example, the defect simulation hole with a height h1 is about 10 mm away from the height of the second working surface, the defect simulation hole with a height h2 is about 20 mm away from the height of the second working surface, the defect simulation hole with a height h3 is about 30 mm away from the height of the second working surface, and the defect simulation hole with a height h4 is about 40 mm away from the height of the second working surface. These defect simulation holes basically cover defects at different heights in the height direction of the girth weld one, and basically cover the focus depth range of the two focused longitudinal wave angle probes. Each defect simulation hole is formed as a transverse through hole structure on the comparative test block. The weld excess height at the top surface of the girth weld one is ground flat by machining, and is flush with the adjacent base material. The length L of the foregoing comparative test block is about 3P, where P=2KT, K is the tangent value of the probe angle, and T is the pipe wall thickness. S5. Adopting the verification test block shown in Figure 5 and Figure 6 for verifying the ultrasonic testing curve, so as to verify the accuracy of the detection curve. The verification test block is formed by the same process as the object workpiece, including the same material, the same curvature structure, the same wall thickness, the same welding process, etc. The verification test block has a working surface three for detection work by the selected focused longitudinal wave angle probe, and the working surface three is a curved surface structure matching the curvature structure (i.e., wafer curvature Φ273mm) of the focused longitudinal wave angle probe; On the side groove of the girth weld two of the verification test block, a plurality of defect simulation holes two are arranged at a substantially regular interval along the height direction of the weld, for example, the defect simulation hole with a height h1 is about 10mm away from the height of the working surface three, the defect simulation hole with a height h2 is about 20mm away from the height of the working surface three, the defect simulation hole with a height h3 is about 30mm away from the height of the working surface three, and the defect simulation hole with a height h4 is about 40mm away from the height of the working surface three, which substantially covers the defects at different heights in the height direction of the girth weld two, and substantially covers the focusing depth range of the two focused longitudinal wave angle probes, and each defect simulation hole is formed in a transverse through hole structure on the verification test block; The length L of the above verification test block is about 3P, wherein P=2KT, K is the tangent value of the probe angle, and T is the pipe wall thickness; S6. The debug qualified ultrasonic detection equipment is used for girth weld detection of an object workpiece, specifically including the following procedures: Cleaning the detection surface of the object workpiece to remove various impurities including paint, welding spatter, iron filings and oil stains; Polishing the detection surface of the object workpiece to process flatness, removing the weld reinforcement and making it flush with the adjacent base material, so that the gap between the detection surface and the probe wedge or protective film is ≤0.5mm, and the roughness Ra of the detection surface is ≤25μm; When detecting longitudinal defects, the focused longitudinal wave angle probe should be placed vertically on the detection surface, and the range of forward and backward movement of the focused longitudinal wave angle probe should ensure that all cross sections of the welded joint are scanned; In order to observe the dynamic waveform of the defect and distinguish the defect signal or pseudo defect signal, and determine the position, direction and shape of the defect, the basic scanning methods such as forward and backward, left and right can be used.

[0033] The above ultrasonic detection method is repeatedly verified on the object workpiece, that is, after the ultrasonic nondestructive testing is completed, the object workpiece is subjected to air planing according to the detection results, and it is found that the defects and positioning obtained in the detection process are consistent with the defects and positioning found by air planing, and the above ultrasonic detection method has good detection accuracy on the object workpiece.

[0034] Example 3 The present application is an ultrasonic detection method for butt girth welds of austenitic stainless steel pipes, and the object workpiece suitable for the detection method is a high-pressure air system pipeline for wind tunnel test, which is made of 06Cr19Ni10 material, has a pipe diameter and wall thickness of Φ168mm*28mm, and the butt girth weld is an argon arc welding structure.

[0035] The ultrasonic detection method of the present application specifically comprises the following process steps: S1. Based on the pipeline structure as above, the structure of the workpiece to be detected, i.e. the specifications of its pipe diameter and wall thickness, is determined; S2. Based on the structure of the workpiece, a focused longitudinal wave oblique probe is selected; For a structure with a wall thickness of 28 mm, a single focused longitudinal wave oblique probe can cover the focus, so in combination with the effective focus depth, incident angle performance parameters, etc. of the focused longitudinal wave oblique probe, the detection of a wall thickness of 28 mm is defined as a predicted detection depth range of 0-28 mm, so a focused longitudinal wave oblique probe with an effective focus depth of 20 mm is selected, and the model of the selected focused longitudinal wave oblique probe with an effective focus depth of 20 mm is specifically 2MHZ 10×16×2LA60FG20; In order to adapt to the curvature of the pipe diameter Φ168 mm of the workpiece, and to facilitate the emission wave of the ultrasonic wave to maintain high energy, the probe structure of the selected focused longitudinal wave oblique probe is processed into a structure matching the circumferential curvature of the workpiece, i.e. the structure of the probe adopts a wafer curvature of Φ168 mm; S3. The selected focused longitudinal wave oblique probe and the ultrasonic non-destructive testing equipment are subjected to angle calibration processing using the standard test block shown in Figure 1 and Figure 2 with multiple corresponding calibration surfaces, the main parameters calibrated by the standard test block are sound velocity, front, and K value; The standard test block is made of the same material as the workpiece, has a working surface one at the top, and a first calibration surface, a second calibration surface and a third calibration surface arranged at the bottom of the working surface one and distributed in curved surface structure, i.e. the first calibration surface, the second calibration surface and the third calibration surface are arranged on the same side of the working surface one, and the first calibration surface is alone on one side, and the second calibration surface and the third calibration surface are on the same side and arranged in a stepped structure; The working surface one is a curved surface structure matching the curvature structure of the focused longitudinal wave oblique probe (i.e. wafer curvature Φ168 mm), which has good fit with the wafer curvature of the focused longitudinal wave oblique probe, and is beneficial to the emission wave of the ultrasonic wave to maintain high energy, and the curved surface curvature of the working surface one is formed along the axial direction of the standard test block (relative to the circular arc axial direction of each calibration surface) to meet the angle calibration of the focused longitudinal wave oblique probe through the corresponding calibration surface; The first calibration surface is used for calibrating a focused longitudinal wave oblique probe with a focus depth of 20 mm, the second calibration surface is used for calibrating a focused longitudinal wave oblique probe with a focus depth of 40 mm (not involved in the embodiment, and can be idle), and the third calibration surface is used for calibrating a focused longitudinal wave oblique probe with a focus depth of 50 mm (not involved in the embodiment, and can be idle). Therefore, it can be seen that the foregoing standard test block can simultaneously satisfy the calibration of focused longitudinal wave oblique probes with different focus depths, and has good flexibility. S4. Adopting the reference Figure 3 and Figure 4 The contrast test block shown in the figure covers defects at different depth positions of the girth weld. The calibrated focused longitudinal wave oblique probe and the ultrasonic nondestructive testing equipment are used to perform ultrasonic testing curve (i.e., DAC curve) adjustment on the contrast test block to adjust the sensitivity thereof. The contrast test block is formed by the same process as the object workpiece, including the same material, the same curvature structure, the same wall thickness, the same girth weld structure, the same welding process, etc. The contrast test block has a working surface two for the selected focused longitudinal wave oblique probe to perform detection work, and the working surface two is a curved surface structure matching the curvature structure (i.e., wafer curvature Φ168 mm) of the focused longitudinal wave oblique probe. A plurality of defect simulation holes one are arranged at a regular interval along the height direction of the girth weld one at the center of the width of the girth weld one. For example, the defect simulation hole with a height h1 is about 5 mm away from the height of the working surface two, the defect simulation hole with a height h2 is about 15 mm away from the height of the working surface two, and the defect simulation hole with a height h3 is about 25 mm away from the height of the working surface two. These defect simulation holes basically cover defects at different heights in the height direction of the girth weld one, and basically cover the focus depth range of the selected focused longitudinal wave oblique probe. Each defect simulation hole is formed as a transverse straight hole structure on the contrast test block. The weld reinforcement at the top surface of the girth weld one is ground flat by machining, and is flush with the adjacent base material. The length L of the foregoing contrast test block is about 3P, where P=2KT, K is the tangent value of the probe angle, and T is the pipe wall thickness. S5. Adopting the verification test block shown in Figure 5 and Figure 6 The adjusted focused longitudinal wave oblique probe and the ultrasonic nondestructive testing equipment are used to perform ultrasonic testing curve verification on the verification test block to verify the accuracy of the detection curve. The verification test block is formed by the same process as the object workpiece, including the same material, the same curvature structure, the same wall thickness, the same welding process, etc. The verification test block has a working surface three for the selected focused longitudinal wave oblique probe to perform detection work, and the working surface three is a curved surface structure matching the curvature structure (i.e., wafer curvature Φ168 mm) of the focused longitudinal wave oblique probe. A plurality of defect simulation holes two are arranged at the groove on one side of the girth weld two of the verification test block at a regular interval along the height direction of the weld, for example, the height h1 of the defect simulation hole is about 5mm from the height of the working surface three, the height h2 of the defect simulation hole is about 15mm from the height of the working surface three, and the height h3 of the defect simulation hole is about 25mm from the height of the working surface three. These defect simulation holes basically cover the defects at different heights in the height direction of the girth weld two, and basically cover the focusing depth range of the selected focusing longitudinal wave oblique probe. Each defect simulation hole is formed in a transverse through hole structure on the verification test block; The length L of the above verification test block is about 3P, where P = 2KT, K is the tangent value of the probe angle, and T is the pipe wall thickness; S6. The debug qualified ultrasonic detection equipment is used for girth weld detection of the object workpiece, specifically including the following steps: Cleaning the detection surface of the object workpiece to remove various impurities including paint, welding spatter, iron filings and oil stains; Polishing the detection surface of the object workpiece to process flatness, removing the weld reinforcement and making it flush with the adjacent base material, so that the gap between the detection surface and the probe wedge or protective film is ≤0.5mm, and the roughness Ra of the detection surface is ≤25μm; When detecting longitudinal defects, the focusing longitudinal wave oblique probe should be placed vertically on the detection surface, and the range of forward and backward movement of the focusing longitudinal wave oblique probe should ensure that all cross sections of the welded joint are scanned. In order to observe the dynamic waveform of the defect and distinguish the defect signal or false defect signal, and determine the position, direction and shape of the defect, the basic scanning methods such as forward and backward, left and right can be used.

[0036] The above ultrasonic detection method is repeatedly verified on the object workpiece, that is, after the ultrasonic nondestructive testing is completed, the object workpiece is subjected to air planing according to the detection results, and it is found that the defects and positioning obtained in the detection process are consistent with the defects and positioning found by air planing. The above ultrasonic detection method has good detection accuracy on the object workpiece.

[0037] Example 4 The other contents of this embodiment are the same as those of example 1 or example 2, except that: The selected plurality of focusing longitudinal wave oblique probes have about 30% overlap between different zones when performing zone scanning.

[0038] Example 5 The other contents of this embodiment are the same as those of example 1 or example 2, except that: The selected plurality of focusing longitudinal wave oblique probes have about 15% overlap between different zones when performing zone scanning.

[0039] The above embodiments are only used to illustrate the present application, but not to limit it.

[0040] Those skilled in the art will understand that the above embodiments can be modified or equivalent replacements can be made to some technical features in the above embodiments, and the modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the present application.

Claims

1. An ultrasonic testing method for butt welds of austenitic stainless steel pipes, characterized in that, The ultrasonic testing method includes the following process steps: S1. Determine the structure of the workpiece to be inspected; S2. Based on the structure of the workpiece, select a focusing longitudinal wave angle probe with the corresponding focusing depth; The probe structure of the focused longitudinal wave angle probe is machined to match the circumferential curvature of the target workpiece; S3. Use standard test blocks with corresponding calibration surfaces to calibrate the selected focused longitudinal wave angle probe and ultrasonic non-destructive testing equipment; S4. Adjust the ultrasonic test curve of the calibrated focused longitudinal wave angle probe and ultrasonic non-destructive testing equipment on the comparison test block; S5. Verify the ultrasonic test curve of the adjusted focused longitudinal wave angle probe and ultrasonic non-destructive testing equipment on the verification block; S6. Use the qualified ultrasonic non-destructive testing equipment for the inspection of circumferential welds on the workpiece.

2. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 1, characterized in that: In step S1, the workpiece is a high-pressure air system pipeline used for wind tunnel testing, made of 06Cr19Ni10 material, and the butt joint circumferential weld is an argon arc welded structure.

3. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 1, characterized in that: In step S2, the selection of the focused longitudinal wave angle probe is based on the wall thickness structure of the workpiece and at least one focused longitudinal wave angle probe is selected according to the effective focusing depth range of the focused longitudinal wave angle probe. When selecting multiple focused longitudinal wave angle probes, the selected probes should be scanned in sections during testing, with at least 15% overlap between different sections.

4. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 3, characterized in that: In the structure of the workpiece, the pipe diameter and wall thickness are specified as Φ168mm*28mm, Φ273mm*45mm or 323mm*55mm. Correspondingly, for a workpiece with dimensions of Φ168mm*28mm, the effective focusing depth of the selected focusing longitudinal wave angle probe is 20mm; For a workpiece with a specification of Φ273mm*45mm, the effective focusing depths of the selected focused longitudinal wave angle probes are 20mm and 40mm respectively. During ultrasonic testing, the two types of focused longitudinal wave angle probes are scanned in sections, and there is at least 15% overlap between different sections. For a workpiece with dimensions of 323mm*55mm, the effective focusing depths of the selected focused longitudinal wave angle probes are 15mm, 30mm and 50mm respectively. During ultrasonic testing, the three focused longitudinal wave angle probes are scanned in sections, and there is at least 15% overlap between different sections.

5. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 1, 3, or 4, characterized in that: The effective focusing depth range of the selected focusing longitudinal wave angle probe used on the workpiece is between 15 mm and 50 mm. Correspondingly, in step S3, the standard test block (1) is made of the same material as the object workpiece. The standard test block (1) has a working surface (11) and a first calibration surface (11), a second calibration surface (12) and a third calibration surface (13) respectively distributed in a curved structure based on the working surface (11). The working surface (11) is a curved surface structure that matches the arc structure of the focused longitudinal wave angle probe; The first calibration surface (11) is used as a focusing longitudinal wave angle probe for calibrating focusing depths of 15 mm and 20 mm. The second calibration surface (12) is used to calibrate the focusing longitudinal wave angle probe with a focusing depth of 30 mm and a focusing depth of 40 mm; The third calibration surface (13) is used to calibrate a focusing longitudinal wave angle probe with a focusing depth of 50 mm.

6. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 5, characterized in that: The curvature of the working surface (11) is formed along the axial direction of the standard test block (1); The first calibration surface (11), the second calibration surface (12), and the third calibration surface (13) are arranged on the same side of the working surface (11); Furthermore, the first calibration surface (11) is located on one side, while the second calibration surface (12) and the third calibration surface (13) are arranged in a stepped structure on the same side.

7. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 1, characterized in that: In step S4, the comparison test block (2) is manufactured using the same process as the target workpiece; The comparison test block (2) has a working surface two (23) for the detection operation of the focused longitudinal wave angle probe. The working surface two (23) is a curved surface structure that matches the arc structure of the focused longitudinal wave angle probe. At the center of the width of the circumferential weld seam 1 (21) of the comparative test block (2), a plurality of defect simulation holes 1 (22) are arranged at intervals along the weld height direction.

8. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 1, characterized in that: In step S5, the verification test block (3) is manufactured using the same process as the target workpiece; The verification test block (3) has a working surface three (33) for performing detection work with a focused longitudinal wave angle probe. The working surface three (33) is a curved surface structure that matches the arc structure of the focused longitudinal wave angle probe. At the bevel on one side of the circumferential weld seam 2 (31) of the verification test block (3), there are multiple defect simulation holes 2 (32) arranged at intervals along the weld height direction.

9. The ultrasonic testing method for butt welds of austenitic stainless steel pipes according to claim 1, characterized in that: In step S6, the ultrasonic non-destructive testing equipment inspects the circumferential weld of the workpiece, including the following procedures: Clean the inspection surface of the workpiece to remove impurities including paint, welding spatter, iron filings, and oil stains; The inspection surface of the workpiece is machined to be flat, the excess weld height is removed, and it is flush with the adjacent base material, so that the gap between the inspection surface and the probe wedge or protective film is ≤0.5mm, and the surface roughness Ra is ≤25μm.

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