阅读说明：本技术 曲面双轴肩搅拌摩擦焊缝的超声波相控阵检测方法 (Ultrasonic phased array detection method for curved surface double-shaft shoulder friction stir welding seam ) 是由 张艳辉 侯振国 翟烜 钮旭晶 王萌 鲁二敬 苗佳 郁志凯 于 2021-08-19 设计创作，主要内容包括：本发明提供了一种曲面双轴肩搅拌摩擦焊缝的超声波相控阵检测方法,包括以下步骤：根据曲面型材结构型式确定扫查面的曲率参数；利用相控阵超声探伤仪进行声场模拟,确定声束经过相控阵超声探伤仪的探头楔块的区域范围,并将声束覆盖探头楔块的耦合面的区域标记为耦合区域；根据曲率参数对耦合面进行修磨,修磨区域覆盖耦合区域；根据耦合面的修磨尺寸修正相控阵超声探伤仪的晶片高度参数；将修磨后的耦合区域对准扫查面上的焊缝进行沿线扫查。本发明提供的曲面双轴肩搅拌摩擦焊缝的超声波相控阵检测方法,通过提高探头楔块与扫查面之间的耦合效果,从而能够提高焊缝内部缺陷的定位精度。(The invention provides an ultrasonic phased array detection method for a curved surface double-shaft-shoulder friction stir welding seam, which comprises the following steps of: determining the curvature parameter of a scanning surface according to the structural type of the curved surface profile; performing sound field simulation by using a phased array ultrasonic flaw detector, determining the area range of a sound beam passing through a probe wedge block of the phased array ultrasonic flaw detector, and marking the area of the sound beam covering the coupling surface of the probe wedge block as a coupling area; grinding the coupling surface according to the curvature parameters, wherein the grinding area covers the coupling area; correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the grinding size of the coupling surface; and aligning the polished coupling region to a welding seam on a scanning surface for scanning along the line. According to the ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir welding seam, the coupling effect between the probe wedge block and the scanning surface is improved, so that the positioning accuracy of the internal defects of the welding seam can be improved.)

1. The ultrasonic phased array detection method of the curved surface double-shaft shoulder friction stir welding seam is characterized by comprising the following steps of:

determining the curvature parameter of a scanning surface according to the structural type of the curved surface profile;

performing sound field simulation by using a phased array ultrasonic flaw detector, determining the area range of a sound beam passing through a probe wedge block of the phased array ultrasonic flaw detector, and marking the area of the sound beam covering the coupling surface of the probe wedge block as a coupling area;

grinding the coupling surface according to the curvature parameters, wherein a grinding area covers the coupling area;

correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the grinding size of the coupling surface;

and aligning the polished coupling region to a welding seam on the scanning surface for scanning along the line, wherein the gap between the coupling region and the scanning surface is less than or equal to 0.5 mm.

2. The ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir weld according to claim 1, wherein the grinding the coupling surface according to the curvature parameter, wherein the grinding range covers the coupling area comprises the following steps:

if the scanned surface is a convex surface, locally grinding the coupling surface, wherein a locally ground area completely covers the coupling area;

and if the scanning surface is a concave surface, integrally polishing the coupling surface.

3. The ultrasonic phased array inspection method for the curved double-shoulder friction stir weld according to claim 1, wherein the correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the thinning dimension of the coupling surface comprises:

preparing a test block, and respectively polishing a simulation concave surface and a simulation convex surface on two opposite surfaces of the test block according to the curvature parameters, wherein the distance between the simulation concave surface and the simulation convex surface is greater than or equal to the value of two times of the thickness of the welding seam;

machining simulated defect holes parallel to the simulated concave surface or the simulated convex surface in the test block, and recording actual distance values between the simulated defect holes and the simulated concave surface or the simulated convex surface;

enabling the coupling surface to be close to the simulated concave surface or the simulated convex surface, and enabling the coupling area to be aligned with the simulated defect hole for scanning to obtain a scanning distance value between the simulated defect hole and the simulated concave surface or the simulated convex surface;

and correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the deviation value between the scanning distance value and the actual distance value.

4. The method of claim 3, wherein the modifying the wafer height parameter of the phased array ultrasonic flaw detector based on the deviation between the scanned distance value and the actual distance value comprises:

if the scanned distance value is smaller than the actual distance value, adding the deviation value to the wafer height parameter;

if the scanned distance value is greater than the actual distance value, subtracting the offset value from the wafer height parameter.

5. The ultrasonic phased array detection method for the curved surface double-shaft shoulder friction stir weld according to claim 3, characterized in that verification grooves are respectively processed on the simulation concave surface and the simulation convex surface; before the step of correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the thinning size of the coupling surface, the method further comprises the following steps:

and enabling the coupling surface to be close to the simulation concave surface or the simulation convex surface, enabling the coupling area to be aligned to the verification groove for scanning, and verifying the sensitivity of the phased array ultrasonic flaw detector according to the scanning result.

6. The ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir weld according to claim 5, wherein the verifying the sensitivity of the phased array ultrasonic flaw detector according to the scanning result comprises:

if the scanning result can display the verification groove, the sensitivity of the phased array ultrasonic flaw detector is normal, and debugging is not needed;

and if the scanning result cannot display the verification groove, the gain of the phased array ultrasonic flaw detector needs to be increased until the scanning result can normally display the verification groove.

7. The ultrasonic phased array detection method for the curved surface double-shaft shoulder friction stir welding seam according to claim 3, wherein a plurality of the defect-like holes are processed in the test block, and before the step of aligning the coupling area after grinding with the welding seam on the scanning surface for scanning along the line, the method further comprises the following steps:

after the height parameters of the wafer are corrected, enabling the coupling surface to be close to the simulation concave surface or the simulation convex surface, and enabling the coupling area to be sequentially aligned with each defect simulating hole for scanning;

and comparing the scanning result with the actual distance value of each simulated defect hole, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the comparison result to obtain a TCG curve.

8. The ultrasonic phased array detection method for the curved surface double-shaft shoulder friction stir welding seam according to claim 7, wherein the step of comparing the scanning result with the actual distance value of each simulated defect hole and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the comparison result to obtain the TCG curve comprises the following steps:

respectively obtaining sound wave reflection signals of the simulated defect holes and confirming calibration;

comparing the data of each calibration point with the corresponding actual distance value of the simulated defect hole, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the deviation;

the TCG curve is obtained after calibration is complete.

9. The ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir welding seam according to claim 8, wherein at least three simulated defect holes are processed in the test block, the distances between the at least three simulated defect holes and the simulated concave surface or the simulated convex surface are sequentially increased, and the difference between the maximum distance value and the minimum distance value is larger than the thickness of the welding seam.

10. The ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir weld according to claim 9, characterized in that if the scanning surface is a convex surface, the coupling surface is close to the simulated convex surface and scans each simulated defect hole in sequence, and the simulated defect hole closest to the simulated convex surface is preferentially scanned;

and if the scanning surface is a concave surface, the coupling surface is close to the simulation concave surface, scanning is sequentially carried out on each defect-imitating hole, and the defect-imitating hole closest to the simulation concave surface is preferentially scanned.

Technical Field

The invention belongs to the technical field of nondestructive testing, and particularly relates to an ultrasonic phased array testing method for a curved surface double-shaft-shoulder friction stir welding seam.

Background

In the process of manufacturing rail transit equipment, the wall thickness of a welding seam double-wall section of double-shaft-shoulder friction stir welding is thin, the effect of a ray or a conventional ultrasonic detection method is poor, the reliable detection of the defects of the thin-wall welding seam can be realized by utilizing the sound beam deflection and focusing functions of an ultrasonic phased array technology, the probe and a probe coupling probe wedge block slide on a rail together during the detection, the probe is enabled to scan along a line parallel to the central line of the welding seam and automatically generate a DAC curve (distance amplitude curve) or a TCG curve (depth compensation curve), so that the defects existing in the welding seam are accurately found, at present, the ultrasonic phased array technology is mostly used for scanning the plane type welding seam, but because a large number of curved surface sections are adopted in the rail transit equipment, when the welding seam on the curved surface sections is detected, because the probe wedge block cannot keep consistent gaps with the welding seam and the scanning areas on two sides of the welding seam, therefore, the coupling effect between the probe wedge and the scanning surface is poor, which greatly affects the detection accuracy of the internal defects of the welding seam, especially the judgment of the positions of the defects is easy to generate larger deviation, thereby affecting the subsequent targeted repair work of the welding seam defects.

Disclosure of Invention

The embodiment of the invention provides an ultrasonic phased array detection method for a curved surface double-shaft-shoulder friction stir welding seam, aiming at improving the defect positioning precision of the curved surface double-shaft-shoulder friction stir welding seam.

In order to achieve the purpose, the invention adopts the technical scheme that: the ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir welding seam is provided, and comprises the following steps:

determining the curvature parameter of a scanning surface according to the structural type of the curved surface profile;

performing sound field simulation by using a phased array ultrasonic flaw detector, determining the area range of a sound beam passing through a probe wedge block of the phased array ultrasonic flaw detector, and marking the area of the sound beam covering the coupling surface of the probe wedge block as a coupling area;

grinding the coupling surface according to the curvature parameters, wherein the grinding area covers the coupling area;

correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the grinding size of the coupling surface;

and aligning the polished coupling region to a welding seam on a scanning surface to scan along the line, wherein the gap between the coupling region and the scanning surface is less than or equal to 0.5 mm.

In one possible implementation manner, the coupling surface is polished according to the curvature parameter, and the polishing range covers the coupling area and includes:

if the scanned surface is a convex surface, locally grinding the coupling surface, wherein the locally ground area completely covers the coupling area;

and if the scanning surface is a concave surface, integrally polishing the coupling surface.

In some embodiments, modifying the wafer height parameter of the phased array ultrasonic flaw detector based on the thinning dimension of the coupling surface comprises:

preparing a test block, and respectively polishing a simulation concave surface and a simulation convex surface on two opposite surfaces of the test block according to the curvature parameters, wherein the distance between the simulation concave surface and the simulation convex surface is more than or equal to the value of two times of the thickness of a welding seam;

machining simulated defect holes parallel to the simulated concave surfaces or the simulated convex surfaces in the test block, and recording actual distance values between the simulated defect holes and the simulated concave surfaces or the simulated convex surfaces;

enabling the coupling surface to be close to the simulated concave surface or the simulated convex surface, and enabling the coupling area to be aligned with the simulated defect hole for scanning to obtain a scanning distance value between the simulated defect hole and the simulated concave surface or the simulated convex surface;

and correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the deviation value between the scanning distance value and the actual distance value.

Specifically, the step of correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the deviation value between the scanning distance value and the actual distance value comprises the following steps:

if the scanned distance value is smaller than the actual distance value, adding a deviation value to the wafer height parameter;

if the scanned distance value is greater than the actual distance value, the wafer height parameter is subtracted by the offset value.

In one possible implementation mode, verification grooves are respectively machined on the simulation concave surface and the simulation convex surface; before correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the thinning size of the coupling surface, the method further comprises the following steps:

and (3) enabling the coupling surface to be close to the simulation concave surface or the simulation convex surface, aligning the coupling area to the verification groove for scanning, and verifying the sensitivity of the phased array ultrasonic flaw detector according to the scanning result.

In this embodiment, verifying the sensitivity of the phased array ultrasonic flaw detector according to the scanning result includes:

if the scanning result can display the verification groove, the sensitivity of the phased array ultrasonic flaw detector is normal, and debugging is not needed;

if the scanning result can not display the verification groove, the gain of the phased array ultrasonic flaw detector needs to be increased until the scanning result can normally display the verification groove.

In some embodiments, the test block is internally processed with a plurality of simulated defect holes, and before the step of scanning the ground coupling region along the line with respect to the weld on the scanning surface, the method further includes:

after the height parameters of the wafer are corrected, the coupling surface is close to the simulation concave surface or the simulation convex surface, and the coupling area is sequentially aligned to each simulation defect hole for scanning;

and comparing the scanning result with the actual distance value of each simulated defect hole, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the comparison result to obtain a TCG curve.

Specifically, the scanning result is compared with the actual distance value of each simulated defect hole, the gain compensation parameter of the phased array ultrasonic flaw detector is calibrated according to the comparison result, and the TCG curve is obtained by:

respectively obtaining sound wave reflection signals of each simulated defect hole and confirming calibration;

comparing the data of each calibration point with the actual distance value of the corresponding simulated defect hole, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the deviation;

the TCG curve was obtained after calibration was complete.

Furthermore, at least three simulated defect holes are machined in the test block, the distances between the at least three simulated defect holes and the simulated concave surface or the simulated convex surface are sequentially increased, and the difference value between the maximum distance value and the minimum distance value is larger than the thickness of the welding seam.

In addition, if the scanning surface is a convex surface, the coupling surface is close to the simulation convex surface and scans each simulated defect hole in sequence, and the simulated defect hole closest to the simulation convex surface is scanned preferentially;

and if the scanning surface is a concave surface, the coupling surface is close to the simulation concave surface, scanning is sequentially carried out on each simulated defect hole, and the simulated defect hole closest to the simulation concave surface is preferentially scanned.

The ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir welding seam has the beneficial effects that: compared with the prior art, the ultrasonic phased array detection method for the curved surface double-shaft-shoulder stirring friction welding line is characterized in that the coupling surface of the probe wedge is polished according to the curvature parameter of the scanning surface of the curved surface section bar, and the wafer height parameter of the phased array ultrasonic flaw detector is corrected according to the polishing size of the probe wedge before the welding line on the scanning surface is scanned along the line, so that the influence of the size change caused by polishing of the probe wedge on the scanning result can be avoided, and the polished probe wedge can keep a basically consistent gap of not more than 0.5mm with the scanning surface (the area near the welding line), so that the coupling effect between the probe wedge and the scanning surface can be improved, the positioning precision of the internal defect of the welding line is improved, and the subsequent targeted repair of the welding line defect is facilitated.

Drawings

FIG. 1 is a block diagram of a detection flow of an ultrasonic phased array detection method for a curved surface double-shoulder friction stir weld according to an embodiment of the present invention;

FIG. 2 is a schematic view of the range of the acoustic beam passing through the wedge of the probe in an embodiment of the present invention;

fig. 3 is a schematic structural view of a probe wedge used in the embodiment of the present invention after polishing a curved profile with a convex scan surface;

fig. 4 is a schematic structural view of a probe wedge block adopted in the embodiment of the present invention after polishing a curved profile with a concave scanned surface;

FIG. 5 is a schematic top view of a test block according to an embodiment of the present invention;

FIG. 6 is a schematic view of a structural state of a simulated defect hole scanning on a simulated convex surface according to an embodiment of the present invention;

FIG. 7 is a schematic view of a structural state of a simulated defect hole scanning on a simulated concave surface according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a structural state of a verification slot scan for a simulated convex surface according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a structural state of a verification groove scan for a simulated concave surface according to an embodiment of the present invention;

fig. 10 is a schematic diagram of a normal display of the verification slot during sensitivity verification according to an embodiment of the present invention.

In the figure: 1. a probe wedge block; 10. a sound beam region; 11. a coupling surface; 12. a coupling region; 2. testing blocks; 21. simulating a convex surface; 22. simulating a concave surface; 23. simulating defect holes; 24. the slot is verified.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 4, the ultrasonic phased array inspection method for the curved surface dual-shoulder friction stir weld according to the present invention will now be described. The ultrasonic phased array detection method of the curved surface double-shaft shoulder friction stir welding seam comprises the following steps:

determining the curvature parameter of a scanning surface according to the structural type of the curved surface profile;

performing sound field simulation by using a phased array ultrasonic flaw detector, determining the area range (namely a sound beam area 10) of a sound beam passing through a probe wedge block 1 of the phased array ultrasonic flaw detector, and marking the area of the sound beam covering a coupling surface 11 of the probe wedge block 1 as a coupling area 12;

grinding the coupling surface 11 according to the curvature parameters, wherein the grinding area covers the coupling area 12;

correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the grinding size of the coupling surface 11;

and aligning the polished coupling region 12 to a welding seam on a scanning surface for scanning along the line, wherein the clearance between the coupling region 12 and the scanning surface is less than or equal to 0.5 mm.

It should be understood that, before the phased array ultrasonic flaw detector performs scanning detection on a weld of a scanning surface, a TCG curve is obtained through test block testing, the TCG curve is displayed on an image automatically generated by the phased array ultrasonic flaw detector after the weld scanning is finished, and the specific position of the internal flaw of the weld can be accurately positioned according to the relative position relationship between the flaw displayed on the image and the TCG curve; because the boundary of the coupling region 12 needs to be referred when the coupling surface 11 is polished, the coupling region 12 needs to be determined and marked on the coupling surface 11, and when the coupling region 12 is determined, a sound field can be simulated according to the number of the excitation array elements and the incident angle of the sound wave of the phased array ultrasonic flaw detector, so that the region range of the sound beam passing through the coupling surface 11 is determined, namely the coupling region 12.

Compared with the prior art, the ultrasonic phased array detection method for the curved surface double-shaft-shoulder friction stir welding seam provided by the embodiment is characterized in that the coupling surface 11 of the probe wedge 1 is polished based on the curvature parameter of the scanning surface of the curved surface section bar, and before the welding seam on the scanning surface is scanned along the line, the wafer height parameter of the phased array ultrasonic flaw detector is corrected according to the polishing size of the probe wedge 1, so that the influence of the size change caused by polishing of the probe wedge 1 on the scanning result can be avoided, and the polished probe wedge 1 can keep a basically consistent gap of not more than 0.5mm with the scanning surface (the area near the welding seam), so that the coupling effect between the probe wedge 1 and the scanning surface can be improved, the positioning precision of the internal defect of the welding seam is improved, and the subsequent targeted repair of the welding seam defect is facilitated.

In a possible implementation, referring to fig. 3 and 4, the coupling surface 11 is ground according to the curvature parameter, and the grinding range covers the coupling area 12 includes: if the scanned surface is a convex surface, locally grinding the coupling surface 11, wherein the locally ground area completely covers the coupling area 12; if the scanning surface is a concave surface, the coupling surface 11 is integrally polished.

Aiming at the diversification of curved surface section bars, the position of a welding seam of the curved surface section bar can be a convex surface type or a concave surface type, if a scanning surface is a convex surface, the coupling surface 11 of the probe wedge block 1 needs to be polished into a concave surface type which is consistent with or slightly smaller than the curvature parameter of the convex surface, at the moment, the size of the coupling surface 11 of the probe wedge block 1 is far smaller than the area of the scanning surface, so long as the polishing area can cover the coupling area 12 for scanning the welding seam, the whole coupling surface 11 does not need to be polished, the polishing workload can be reduced on one hand, and the polishing size of the probe wedge block 1 can be reduced on the other hand, thereby avoiding the condition that the correction size of the height parameter of a wafer is too large due to the overlarge polishing size, and even the probe wedge block 1 cannot be matched for use; if the scanning surface is a concave surface, the coupling surface 11 of the probe wedge 1 should be polished to a convex surface pattern which is consistent with or slightly larger than the curvature parameter of the concave surface, and in order to ensure the consistency of the gap between the coupling region 12 and the scanning surface during detection, the coupling surface 11 needs to be polished integrally, so that the situation that the coupling region 12 cannot approach the scanning surface and cannot be reliably coupled due to interference between the edge of the coupling surface 11 and the scanning surface is avoided.

In some embodiments, referring to fig. 1, 5-7, modifying the wafer height parameter of the phased array ultrasonic flaw detector according to the thinning dimension of the coupling surface 11 comprises:

preparing a test block 2, and respectively grinding a simulation concave surface 22 and a simulation convex surface 21 on two opposite surfaces of the test block 2 according to curvature parameters, wherein the distance between the simulation concave surface 22 and the simulation convex surface 21 is more than or equal to the double thickness value of a welding seam;

processing a simulated defect hole 23 parallel to the simulated concave surface 22 or the simulated convex surface 21 in the test block 2, and recording an actual distance value between the simulated defect hole 23 and the simulated concave surface 22 or the simulated convex surface 21;

approaching the coupling surface 11 to the simulated concave surface 22 or the simulated convex surface 21, and aligning the coupling region 12 to the simulated defect hole 23 for scanning to obtain a scanning distance value between the simulated defect hole 23 and the simulated concave surface 22 or the simulated convex surface 21;

and correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the deviation value between the scanning distance value and the actual distance value.

Because the scanning surface of the curved-surface profile usually has both a concave surface and a convex surface, the simulation concave surface 22 and the simulation convex surface 21 are arranged on the test block 2, so that the structural types of the two scanning surfaces can be simulated respectively, and the universality of the test block 2 is improved; moreover, because the distance between the simulated concave surface 22 and the simulated convex surface 21 (i.e. the thickness of the test block 2) is at least twice the thickness of the weld (the thickness of the weld by friction stir welding is consistent with the thickness of the curved profile, the thickness of the test block 2 can be specifically 10mm if the thickness of the curved profile is not more than 5mm, and the thickness of the test block 2 is twice the thickness of the curved profile if the thickness of the curved profile is more than 5 mm), the interference effect on the other surface can be avoided when scanning is performed on the simulated concave surface 22 or the simulated convex surface 21; since the distance value of the simulated defect hole 23 from the simulated concave surface 22 or the simulated convex surface 21 in the test block 2 is known, the known distance value can be used as a correction reference of the wafer height parameter, that is, a deviation value between a scanning distance value obtained after scanning the simulated defect hole 23 and an actual distance value is a correction value of the wafer height parameter.

Specifically, the step of correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the deviation value between the scanning distance value and the actual distance value comprises the following steps: if the scanned distance value is smaller than the actual distance value, adding a deviation value to the wafer height parameter; if the scanned distance value is greater than the actual distance value, the wafer height parameter is subtracted by the offset value.

In a possible implementation, referring to fig. 1, 8 to 10, the simulated concave surface 22 and the simulated convex surface 21 are respectively processed with a verification groove 24; before correcting the wafer height parameter of the phased array ultrasonic flaw detector according to the thinning size of the coupling surface 11, the method further comprises the following steps: and (3) approaching the coupling surface 11 to the simulated concave surface 22 or the simulated convex surface 21, aligning the coupling area 12 to the verification groove 24 for scanning, and verifying the sensitivity of the phased array ultrasonic flaw detector according to the scanning result.

In this embodiment, verifying the sensitivity of the phased array ultrasonic flaw detector according to the scanning result includes: if the scanning result can display the verification groove 24, the sensitivity of the phased array ultrasonic flaw detector is normal, and debugging is not needed; if the scanning result can not display the verification groove 24, the gain of the phased array ultrasonic flaw detector needs to be increased until the scanning result can normally display the verification groove 24.

The depth and the width of the verification groove 24 can be set to be 0.5mm, the verification groove 24 is used for simulating a joint line of a welding line and a curved profile, whether the phased array ultrasonic flaw detector can accurately capture the welding line on a scanned surface can be judged by scanning the verification groove 24 on the surface of the simulated concave surface 22 or the simulated convex surface 21, if the scanning result cannot display the verification groove 24, the sensitivity is insufficient, the gain needs to be increased until the verification groove 24 can be clearly displayed on an imaging picture, of course, if the gain is increased, the verification groove 24 cannot be displayed, the probe wedge 1 cannot be subjected to matching detection (the incident angle of sound waves is not matched, the inclined angle of the probe wedge 1 is related to the incident angle of sound beams emitted by a probe), and the probe wedge 1 is required to be prepared again.

In some embodiments, referring to fig. 1, 5 to 7, the test block 2 is internally processed with a plurality of defect-like holes 23, and before the step of performing the line scanning on the ground coupling region 12 aligned with the weld seam on the scanning surface, the step further includes: after the height parameters of the wafer are corrected, the coupling surface 11 is close to the simulated concave surface 22 or the simulated convex surface 21, and the coupling area 12 is sequentially aligned to each simulated defect hole 23 for scanning; and comparing the scanning result with the actual distance value of each simulated defect hole 23, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the comparison result to obtain a TCG curve.

Selecting a position close to the simulated convex surface 21 or the simulated concave surface 22 according to the scanning surface form of the curved-surface profile to scan the simulated defect holes 23, comparing the scanning result with the actual distance value of each simulated defect hole 23, if the deviation between the scanning value and the actual value is within a reasonable range, calibrating correction parameters are not needed, if the deviation between the scanning value and the actual value exceeds the reasonable range, the scanning detection precision is insufficient, and the gain compensation parameters are calibrated, so that the obtained TCG curve meets the precision requirement, the accurate position of the internal defect of the welding seam is obtained after the welding seam is scanned, and the defect positioning precision is improved.

Specifically, comparing the scanning result with the actual distance value of each simulated defect hole 23, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the comparison result, wherein the step of obtaining the TCG curve comprises: respectively obtaining sound wave reflection signals of the simulated defect holes 23 and confirming calibration; comparing the data of each calibration point with the actual distance value of the corresponding simulated defect hole 23, and calibrating the gain compensation parameter of the phased array ultrasonic flaw detector according to the deviation; the TCG curve was obtained after calibration was complete.

When the acoustic beam reaches the simulated defect hole 23, the acoustic beam is reflected to generate an echo (namely a reflected signal), the position generated by the echo represents the position of the simulated defect hole 23 in the test block 2, the principle of the TCG curve is that the amplitude of the reflected echo of each simulated defect hole 23 tends to be consistent through compensation, and the amplitude of the echo is directly related to the position of the simulated defect hole 23 under the uncompensated condition, and the scanning value of the simulated defect hole 23 is close to or even equal to the actual value by comparing the deviation condition of the scanning value and the actual distance value of the phased array ultrasonic flaw detector and calibrating the compensation parameter according to the deviation condition, so that the accuracy of the finally obtained TCG curve can be improved, and the positioning accuracy of the internal defect of the weld joint can be improved.

Further, at least three simulated defect holes 23 are machined in the test block 2, the distances between the at least three simulated defect holes 23 and the simulated concave surface 22 or the simulated convex surface 21 are sequentially increased, and the difference value between the maximum distance value and the minimum distance value is larger than the thickness of the weld joint. In addition, if the scanning surface is a convex surface, the coupling surface 11 is close to the simulated convex surface 21 and scans each simulated defect hole 23 in sequence, and the simulated defect hole 23 closest to the simulated convex surface 21 is scanned preferentially; if the scanning surface is a concave surface, the coupling surface 11 is close to the simulated concave surface 22, scanning is sequentially performed on each simulated defect hole 23, and the simulated defect hole 23 closest to the simulated concave surface 22 is preferentially scanned. The maximum distance between the three defect-imitating holes 23 perpendicular to the scanning surface is larger than the thickness of the welding seam, so that the defects in the whole thickness direction of the welding seam can be scanned, omission is avoided, and the detection reliability is improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.