Sensitivity evaluation method and test piece for radiographic detection of longitudinal defects in tube-tube-sheet welds

Abstract

The present invention provides a method for evaluating the sensitivity of radiographic detection of longitudinal defects in tube-tube sheet fillet welds. The sensitivity test piece involved in the method comprises circumferential grooves of different specifications, which can be used to evaluate the sensitivity of radiographic detection of longitudinal volume and area defects such as strip defects, chain pores, incomplete penetration, incomplete fusion, cracks, etc. at different positions in the tube-tube sheet fillet welds. The method has low detection cost, high efficiency and good versatility.

Description

Technical Field

[0001] The invention relates to the field of nondestructive testing, in particular to a ray detection method and related test pieces, and in particular to a method for evaluating the sensitivity of ray detection of longitudinal defects of a tube-tube sheet weld and a test piece used for evaluating the sensitivity in the method. Background Art

[0002] Tube-tube sheet welding structures are widely used in shell-and-tube heat exchangers such as steam generators in pressurized water reactor nuclear power plants and high-pressure heaters in thermal power plants. The welding quality of tube-tube sheet welds greatly affects the service life of the heat exchanger. In order to verify the welding quality of tube-tube sheet welds, penetration testing and radiographic testing are currently used. Due to its structural characteristics, special equipment and special testing processes are required for radiographic testing of tube-tube sheet welds. Especially in the field of nuclear power, the application conditions of steam generators are more stringent, and the requirements for tube-tube sheet welding are higher. Comprehensive testing of welds is required to ensure that steam generators can work for a long time under high temperature and high pressure irradiation.

[0003] According to current production practice experience, image quality meters are not placed during radiographic inspection, but sensitivity identification tests are used to ensure that the sensitivity of radiographic inspection meets the inspection requirements. In the sensitivity identification test, different sensitivity levels are often characterized by machining small holes of different sizes on the weld surface of the tube-tube sheet fillet weld sample. This method is costly, inefficient, and has poor versatility. It can only verify the sensitivity of pore volume defect detection on the surface of the workpiece, but cannot verify the sensitivity of other types of defects in other locations in the inspection area, and cannot prove that the sensitivity within the entire tube-tube sheet fillet weld inspection volume can meet the inspection requirements.

[0004] Therefore, there is an urgent need for a method for evaluating the sensitivity of radiographic detection of longitudinal defects in tube-to-tube sheet welds, so as to evaluate the sensitivity of radiographic detection of longitudinal volume or area defects such as strip defects, chain pores, incomplete penetration, lack of fusion, cracks, etc. at any position in the inspected area of ​​the tube-to-tube sheet weld. Summary of the invention

[0005] In order to solve the above problems, the inventors have conducted intensive research and developed a method for evaluating the sensitivity of radiographic detection of longitudinal defects in tube-tube sheet welds. This method can be used to evaluate the sensitivity of radiographic detection of longitudinal defects at any position of tube-tube sheet welds. The test piece used in this method has multiple circumferential grooves of different positions and specifications, which are used to simulate longitudinal volume and area defects such as strip defects, chain-shaped pores, incomplete penetration, incomplete fusion, cracks, etc. at any position in the tube-tube sheet weld. The test piece is small and thin, easy to arrange, adjustable in position, flexible in use, and has certain versatility, thereby completing the present invention.

[0006] The first aspect of the present invention aims to provide a method for evaluating the sensitivity of longitudinal defects of tube-tube sheet welds by radiographic detection. The method uses a circumferential groove sensitivity test piece to simulate longitudinal defects of welds for sensitivity evaluation, and specifically comprises the following steps:

[0007] Step 1: According to the structural characteristics of the test piece, a circumferential groove sensitivity test piece is selected to form a simulated part;

[0008] Step 2: Use the proposed radiographic testing process to perform radiographic testing on the simulated part;

[0009] Step 3: Analyze the test results and evaluate the sensitivity of the X-ray detection process used.

[0010] The second aspect of the present invention aims to provide a test piece for evaluating the sensitivity of radiographic detection of longitudinal defects in tube-tube sheet welds, wherein the test piece is a circumferential groove sensitivity test piece, and a circumferential groove is arranged on the circumferential groove sensitivity test piece.

[0011] The material of the test piece is the same as or similar to the metal material of the location in the tube-tube sheet weld where the sensitivity is to be evaluated.

[0012] According to the principle of X-ray detection, the material of the test piece has a certain versatility. When the material of the test piece is carbon steel, low alloy steel or 300 series austenitic stainless steel, it can be used for various steel parts to be inspected, including various carbon steels, low alloy steels and stainless steels.

[0013] The third aspect of the present invention aims to provide the test piece for characterizing the sensitivity level of radiographic inspection of tube-tube sheet fillet welds.

[0014] The beneficial effects of the present invention include:

[0015] (1) The method for evaluating the sensitivity of radiographic detection of longitudinal defects of tube-tube sheet welds provided by the present invention is easy to operate and implement, and is convenient for evaluating the sensitivity of radiographic detection processes.

[0016] (2) The circumferential groove sensitivity test piece provided by the present invention can simulate longitudinal volumetric and area defects of different sizes at different positions in the weld by adjusting the position of the test piece in the simulation part, by adjusting the position of the circumferential groove in the test piece, and by adjusting the width and depth of the circumferential groove, thereby achieving the purpose of evaluating the sensitivity of X-ray detection of longitudinal defects at any position in the weld.

[0017] (3) The test piece provided by the present invention is easy to adjust, has strong versatility, low processing cost, and more flexible operation.

[0018] (4) The circumferential groove provided by the present invention has a standard size, has a certain degree of universality and representativeness, and provides a reference for establishing a sensitivity level standard for radiographic detection of longitudinal defects in tube-tube sheet welds. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a circumferential groove sensitivity test piece 1 in one embodiment of the present invention is shown;

[0020] Figure 2 A schematic diagram of the structure of the test piece 2 in one embodiment of the present invention is shown;

[0021] Figure 3 A schematic diagram of assembling a typical tube-tube sheet weld gamma-ray inspection tool 3 in one embodiment of the present invention is shown;

[0022] Figure 4 A schematic diagram of assembling the simulation member 4 in one embodiment of the present invention is shown, wherein the dotted line in the figure corresponds to the position of the tube 202 in the test object 2;

[0023] Figure 5 A schematic diagram of a transillumination of a simulation member 4 in one embodiment of the present invention is shown, wherein the dotted line in the figure corresponds to the position of the tube 202 in the test object 2;

[0024] Figure 6 A schematic diagram showing the position of the circumferential groove sensitivity test piece 1 in the simulation piece 4 relative to the test piece 2 in one embodiment of the present invention.

[0025] Description of Figure Numbers

[0026] 1- Circumferential groove sensitivity test piece;

[0027] 101- circumferential groove;

[0028] 2-Parts to be inspected;

[0029] 201-tube sheet;

[0030] 202-pipe;

[0031] 203-tube-tube sheet weld;

[0032] 3-A typical tube-tube sheet weld gamma ray inspection tool;

[0033] 301- source conduit;

[0034] 302- shielding plate;

[0035] 303-hidden pocket;

[0036] 304- filter plate;

[0037] 305-compensation block;

[0038] 306-ray source;

[0039] 4- Simulation parts;

[0040] 401-gasket;

[0041] 402-pad;

[0042] 5-ray beam. DETAILED DESCRIPTION

[0043] The present invention is described in detail below through specific implementation modes, and the characteristics and advantages of the present invention will become clearer and more specific with these descriptions.

[0044] In the description of the present invention, it should be noted that the terms "upper", "lower", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or part referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0045] The method for evaluating the sensitivity of longitudinal defects of tube-tube sheet welds by radiographic detection provided by the present invention can evaluate the sensitivity of longitudinal defects of different positions, sizes and types in welds by radiographic detection. The method is convenient and flexible to use, has strong versatility, is easy to adjust, and can realize the evaluation of the sensitivity of longitudinal defects of any position in welds by radiographic detection.

[0046] The method uses the circumferential groove on the test piece to simulate the longitudinal defects in the weld to evaluate the sensitivity of radiographic detection, and specifically includes the following steps:

[0047] Step 1: According to the structural characteristics of the test piece 2, a circumferential groove sensitivity test piece 1 is selected to form a simulated piece 4.

[0048] Part 2 to be inspected is a tube-tube sheet weld. A typical tube-tube sheet strength weld structure is as follows: Figure 2 A tube hole perpendicular to the surface is drilled on the tube sheet 201, and the diameter of the tube hole matches the tube 202. The tube 202 penetrates into the tube hole of the tube sheet and extends a distance from the surface of the tube sheet. The tube 202 and the tube sheet 201 are welded to form a fillet weld 203.

[0049] When evaluating the radiographic sensitivity level of longitudinal defects of tube-tube sheet welds, several key positions where the radiographic detection sensitivity needs to be evaluated should generally be determined based on the geometric dimensions, assembly, welding process, material and other characteristics of the fillet weld 203, and the position parameters of these key positions should be calculated. Among them, the distance from the key position to be evaluated for sensitivity to the central axis of the tube 202 is used to determine the position parameters of the circumferential groove 101 on the circumferential groove sensitivity test piece 1; the distance from the key position to be evaluated for sensitivity to the upper surface of the tube sheet 201 is used to determine the total thickness of the gasket 401 superimposed on the circumferential groove sensitivity test piece 1.

[0050] The circumferential groove sensitivity test piece 1 is a thin sheet with parallel upper and lower surfaces, and its outer contour can be polygonal or circular, with a central through hole perpendicular to the surface at its center, and circumferential grooves 101 of different specifications on its upper surface, wherein the circumferential grooves 101 arranged on the same circumferential groove sensitivity test piece 1 have the same groove width and different groove depths.

[0051] The upper and lower surfaces of the circumferential groove sensitivity test piece 1 should be parallel and flat. Preferably, the parallelism and flatness tolerances should not exceed 5% of its thickness. The thickness of the circumferential groove sensitivity test piece 1 should not be less than the depth of the circumferential groove 101 required on the test piece. The thickness of the test piece should facilitate the processing of the circumferential groove 101 and ensure the processing dimension tolerance of the circumferential groove 101. For the convenience of processing and use, the thickness of the circumferential groove sensitivity test piece 1 can be 0.5-5 mm, preferably 1-2 mm.

[0052] The outer contour of the circumferential groove sensitivity test piece 1 can be polygonal or circular and can be customized as required, but it must not affect the function of the circumferential groove 101. In practical application, the outer contour is not less than 5mm from the circumferential groove 101 to meet the use requirements.

[0053] The shape and size of the central through hole of the circumferential groove sensitivity test piece 1 should match the cross-sectional shape of the tube 202 , and preferably be the same as the inner diameter of the tube 202 .

[0054] The upper surface of the circumferential groove sensitivity test piece 1 is provided with a plurality of circumferential grooves 101, and the circumferential grooves 101 are distributed on a circle concentric with the central through hole of the circumferential groove sensitivity test piece 1. The specification parameters of the circumferential groove 101 in the present invention, namely the groove width and groove depth, are standardized. The position parameter of the circumferential groove 101 in the present invention, namely the distance from the axis of the central through hole of the test piece, should be determined according to the distance from the central axis of the tube 202 to the key position to be evaluated for sensitivity. The circumferential groove 101 may be a rectangular groove or a U-shaped groove according to its cross-sectional shape, but it shall not be a V-shaped groove. The length of a single circumferential groove 101 is not less than 5 mm to meet the use requirements, and it is preferred that the circumferential groove 101 covers the entire circumference.

[0055] The circumferential groove 101 has a groove depth of 1 to 5, preferably 4.

[0056] The specification parameters of the circumferential groove 101, the numerical values ​​of the groove width and groove depth can be selected from a continuous decimal series, such as ... 1.00, 0.90, 0.80, 0.70, 0.60, 0.50, 0.40, 0.30, 0.20, 0.10 ... or R10 series priority series, such as ... 1.00, 0.80, 0.63, 0.50, 0.40, 0.32, 0.25, 0.20, 0.16, 0.125, 0.10 ... preferably R10 series priority series. In a further preferred embodiment, when the groove width is the nth value in the R10 number system, the groove depth value is preferably selected from one or more of the n-2th, n-1th, nth, n+1th and n+2th values.

[0057] In practice, it is found that a typical implementation scheme that can be generally applied is to set 8 circumferential grooves 101 on the test piece, all of which have the same groove width and central angle of 45°, and are distributed along the same circle concentric with the central through hole of the test piece. There are four kinds of groove depths of the circumferential grooves 101, each of which has two circumferential grooves and is symmetrically distributed on the test piece. The circumferential grooves 101 of four different groove depths are arranged in the order of groove depth or in reverse order on the circumferential groove sensitivity test piece 1, such as Figure 1 shown.

[0058] In the present invention, the material of the circumferential groove sensitivity test piece 1 should be the same as or similar to the material of the test piece 2. According to the principle of radiographic detection, as long as the radiation absorption coefficient of the material of the circumferential groove sensitivity test piece 1 is not greater than the radiation absorption coefficient of the material of the test piece 2, it is sufficient, but the difference should not be too large. Preferably, when the material of the circumferential groove sensitivity test piece 1 is carbon steel, low alloy steel or 300 series austenitic stainless steel, the applicable materials of the test piece 2 include various carbon steels, low alloy steels and stainless steels.

[0059] The simulation component 4 includes a gasket 401 and a cushion block 402 . The gasket 401 and the cushion block 402 are provided with a central through hole perpendicular to the surface, and the central through hole has the same size as the central through hole of the circumferential groove sensitivity test piece 1 .

[0060] In order to adjust the position of the circumferential groove sensitivity test piece 1 along the axial direction of the tube 202, a gasket 401 and a pad 402 should also be made. The material of the gasket 401 and the pad 402 should be the same or similar to that of the test piece 2. There is a central through hole perpendicular to the surface on the gasket 401 and the pad 402, and the shape and diameter of the central through hole match the tube 202, preferably the same as the inner diameter of the tube 202. The thickness of the gasket 401 is preferably 0.5mm to 5mm, and further preferably 0.5mm and 1mm, so as to facilitate the adjustment of the position of the circumferential groove sensitivity test piece 1 by stacking layers. The outer contour of the gasket 401 only needs to ensure that it can cover the range of the beam 5, and is usually not less than the outer contour of the circumferential groove sensitivity test piece 1 to meet the use requirements. The thickness of the pad 402 is determined according to the needs, and it only needs to be thick enough and large enough to ensure that the range of the beam 5 is covered. The upper and lower surfaces of the gasket 401 and the pad 402 should be sufficiently flat, and usually the flatness does not exceed 0.05mm to meet the use requirements.

[0061] When in use, the gasket 401, the circumferential groove sensitivity test piece 1 and the cushion block 402 are stacked and assembled into a simulation part 4, such as Figure 4 As shown, the dotted line in the figure corresponds to the position of the tube 202 in the test object 2.

[0062] Step 2: Use the proposed X-ray detection process to perform radiographic inspection on the simulated parts.

[0063] A typical tube-tube sheet weld gamma ray inspection tool 3 Figure 3 As shown. The typical tube-tube sheet weld gamma ray inspection tool 3 comprises a source guide tube 301, a shielding plate 302, a dark bag 303, a filter plate 304, a compensation block 305 and a radiation source 306. The dark bag 303 is equipped with an intensifying screen and a radiation film, the dark bag 303 is clamped by the shielding plate 302 and the filter plate 304, and the compensation block 305 is installed on the filter plate 304. Concentric and sized detection holes are provided on the shielding plate 302, the dark bag 303, the filter plate 304 and the compensation block 305. When transilluminating, the source guide tube 301 is inserted into the detection hole to ensure that the radiation source 306 can reach the designated position, and the inspected part 2 or the simulated part 4 is transilluminated.

[0064] In order to evaluate the sensitivity of radiographic detection of longitudinal defects in tube-tube sheet welds, the same detection tool 3 as that used to detect the test piece 2 is used to perform radiographic detection on the simulated piece 4 using the proposed radiographic detection process, such as Figure 5As shown. By increasing or decreasing the number of gaskets 401, the position of the circumferential groove sensitivity test piece 1 in the simulation part 4 is adjusted, so as to achieve the purpose of evaluating the sensitivity of the longitudinal defect radiographic detection at any position of the tube sheet 201 surface in the tube-tube sheet weld 203. By replacing different circumferential groove sensitivity test pieces 1, the distance between the circumferential groove 101 and the axis of the central through hole of the circumferential groove sensitivity test piece 1 is adjusted, so as to achieve the purpose of evaluating the sensitivity of the longitudinal defect radiographic detection at any distance from the central axis of the tube 202 in the tube-tube sheet weld 203. By replacing different circumferential groove sensitivity test pieces 1, the groove width and groove depth of the circumferential groove 101 are adjusted, so as to achieve the purpose of evaluating the sensitivity of the longitudinal defect radiographic detection of different sizes in the tube-tube sheet weld 203.

[0065] A series of transilluminations are performed on the simulated parts to obtain multiple radiographic films, which are then processed in a darkroom and observed and evaluated in the film evaluation room.

[0066] Step 3: Analyze the test results and evaluate the sensitivity of the X-ray detection process used.

[0067] Observe a series of X-ray negatives obtained in step 2. Since the circumferential grooves 101 of the same specification on each circumferential groove sensitivity test piece 1 are symmetrically distributed, according to the X-ray detection principle, if the X-ray source 306 is centered, that is, the X-ray source 306 is located on the central axis of the central through hole of the simulation component 4, the blackness and length of the images of the circumferential grooves 101 of the same specification should be equal. On the contrary, it can be judged whether the X-ray source 306 is centered based on the blackness and length of the images of the circumferential grooves 101 of the same specification.

[0068] Fill in the data record table according to the identifiable conditions of the circumferential groove 101 on the radiographic film. Analyze the data table to study the identifiable conditions of the circumferential grooves 101 of different sizes at the same position in the simulation part 4.

[0069] According to the identifiable situation of circumferential grooves 101 of different sizes at the same position in the simulated part 4, the sensitivity of the radiographic detection of the longitudinal defects at the corresponding position in the inspected part 2 can be evaluated. Conversely, when it is required that the longitudinal defects of two specified sizes at two specified positions of the inspected part should be identified, it can be used to evaluate whether the radiographic detection process parameters meet the requirements, and then adjust the radiographic detection process parameters.

[0070] The present invention provides a circumferential groove sensitivity test piece 1 for evaluating the sensitivity of radiographic detection of longitudinal defects of a tube-tube sheet weld. The circumferential groove sensitivity test piece 1 is as described in step 1.

[0071] The circumferential groove 101 on the circumferential groove sensitivity test piece 1 of the present invention can simulate longitudinal defects such as strip defects, chain-shaped pores, incomplete penetration, incomplete fusion, cracks, etc. along the direction of the tube-tube sheet weld. The test piece provided by the present invention is easy to adjust, has strong versatility, low processing cost, and more flexible operation. The circumferential groove 101 provided by the present invention has a standard size, has certain versatility and representativeness, and provides a reference for establishing a sensitivity level standard for radiographic detection of longitudinal defects of tube-tube sheet welds.

[0072] Example

[0073] Verify the sensitivity level of radiographic inspection of longitudinal defects in the tube-tube sheet weld of a high-pressure heater in a thermal power station.

[0074] The weld structure of the tube-tube sheet of the test piece 2 is as follows: Figure 2 As shown, the material of the tube sheet 201 is low alloy steel, and the material of the tube 202 is austenitic stainless steel; after the tube is inserted into the tube hole, it extends 2mm to 3mm from the outer surface of the tube sheet, and after the tube is expanded, it is welded to the tube sheet to form a strength weld fillet weld 203. The inner diameter of the tube after expansion is about 16mm. The weld depth is 3mm and the weld width is 3mm. The key position for evaluating the sensitivity of longitudinal defect detection of the weld is determined to be the weld groove position with the most unfavorable radiographic penetration, that is, 3mm away from the upper surface of the tube sheet along the axis of the tube, and 11mm away from the axis of the tube along the radial direction of the tube. The sensitivity requirement of radiographic detection is to be able to identify circumferential grooves with a groove width of 0.5mm and a groove depth of 0.5mm.

[0075] Before testing, the circumferential groove sensitivity test piece 1, gasket 401 and pad 402 are assembled into a simulation part 4. The materials of the circumferential groove sensitivity test piece 1, gasket 401 and pad 402 are all austenitic stainless steel. The circumferential groove sensitivity test piece 1 is a circular thin sheet with an outer diameter of 40mm, a thickness of 2mm and a center hole diameter of 16mm. The groove width of the circumferential groove 101 is 0.5mm, and the four groove depths are grouped together, namely 0.4mm, 0.5mm, 0.63mm and 0.8mm. The two groups of circumferential grooves 101 are distributed on a circle with a radius of 11mm with the center of the circumferential groove sensitivity test piece 1 as the center. The 8 circumferential grooves 101 are equally divided on the circumference, and the central angle of each circumferential groove 101 is 45°. Two gaskets 401 with a thickness of 1mm are stacked on the circumferential groove sensitivity test piece 1, and a pad 402 with a thickness of 40mm is placed under the circumferential groove sensitivity test piece 1. The position of the circumferential groove sensitivity test piece 1 in the simulated part 4 relative to the part to be tested 2 is as follows: Figure 6 shown.

[0076] The X-ray detection tool 3 is provided with a 6mm shielding plate 302 and a 2mm stainless steel filter plate 304. The shielding plate 302 and the filter plate 304 are used to clamp the dark bag 303 to ensure the sealing of the dark bag 303. There are two 0.03mm lead intensifying screens clamping the X-ray film in the dark bag 303. The X-ray film is of C2 grade and the model is Carestream M100.

[0077] The Ir192 radiation source 306 was used for transillumination, the radiation source 306 activity was 0.75Ci, the radiation source 306 focus size was Φ0.5mm, the focal length was 30mm, and the exposure time was 140s. The film was developed using an automatic film processor, and the Carestream machine was used to wash the film. The developing time was 3 minutes, the developing temperature was 28°C, the fixing time was 5 minutes, and the fixing temperature was 28°C.

[0078] The negative film was evaluated under the film viewing light. The film blackness was measured using a densitometer, and the blackness range was 2.3 to 3.7, which met the engineering requirements. Six circumferential grooves 101 can be clearly identified on the negative film, and the image blackness and length of the circumferential grooves of the same size are basically equal, indicating that the radiation source is centered and the transillumination is effective. The smallest circumferential groove 101 size that can be identified is 0.5 mm × 0.5 mm in width × depth.

[0079] In summary, it can be assessed that the sensitivity level of this X-ray detection process within the detection range of this test piece is that it can identify the circumferential groove 101 with a groove width × groove depth of 0.5 mm × 0.5 mm, which meets the engineering requirements.

[0080] The above is only a typical implementation of the present invention for a tube-tube sheet strength weld structure. It should be pointed out that for ordinary technicians in this technical field, the present invention can be directly or slightly modified and applied to a tube-tube sheet sealing weld structure, and these applications should also be regarded as the protection scope of the present invention.

[0081] The above is only a typical implementation of the present invention using the Ir192 gamma-ray source radiographic detection technology. It should be pointed out that for ordinary technicians in this technical field, the present invention can be directly or slightly modified and applied to other gamma-ray source radiographic detection technologies, X-ray radiographic detection technologies, gamma-ray or X-ray digital imaging detection technologies (DR) and gamma-ray or X-ray computer-aided imaging detection technologies (CR), etc. These applications should also be regarded as the protection scope of the present invention.

[0082] The present invention is described in detail above in conjunction with specific embodiments and / or exemplary examples and drawings, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for evaluating the sensitivity of radiographic detection of longitudinal defects in tube-tube sheet fillet welds, characterized in that: The method uses a circumferential groove sensitivity test piece (1) to simulate a longitudinal defect of a weld to perform sensitivity evaluation; The method specifically comprises the following steps: Step 1: According to the structural characteristics of the test piece (2), a circumferential groove sensitivity test piece (1) is selected to form a simulated piece (4); Step 2, using the proposed radiographic inspection process to perform transillumination on the dummy component (4); Step 3: Analyze the test results and evaluate the sensitivity of the X-ray detection process used; The simulation component (4) comprises a gasket (401) and a gasket block (402), wherein the gasket (401) and the gasket block (402) are provided with a central through hole perpendicular to the surface, and the central through hole has the same size as the central through hole of the circumferential groove sensitivity test piece (1); The thickness of the gasket (401) is 0.5 mm and 1 mm, so that the position of the circumferential groove sensitivity test piece (1) can be adjusted by stacking the layers; the outer contour of the gasket (401) is not less than the outer contour of the circumferential groove sensitivity test piece (1); the flatness of the upper and lower surfaces of the gasket (401) and the cushion block (402) does not exceed 0.05 mm; In step 1, a gasket (402), a circumferential groove sensitivity test piece (1) and a plurality of gaskets (401) are stacked and placed for radiographic transillumination.

2. The method according to claim 1, characterized in that In step 1, a central through hole perpendicular to the surface is provided at the center of the circumferential groove sensitivity test piece (1), and the size of the central through hole should match the size of the tube (202) in the test piece (2); A circumferential groove (101) is arranged on the upper surface of the circumferential groove sensitivity test piece (1), wherein the circumferential grooves (101) arranged on the same circumferential groove sensitivity test piece (1) have the same groove width and different groove depths; The circumferential groove (101) has four groove depths.

3. The method according to claim 1, characterized in that: In step 1, the numerical values ​​of the groove width and groove depth of the circumferential groove (101) are selected from a continuous decimal series, or an R10 series priority series.

4. The method according to claim 1, characterized in that In step 1, before testing, the circumferential groove sensitivity test piece (1), the gasket (401), the gasket block (402) and a typical tube-tube sheet weld gamma-ray detection tool (3) are assembled, wherein the typical tube-tube sheet weld gamma-ray detection tool (3) comprises a source guide tube (301), a shielding plate (302), a dark bag (303), a filter plate (304), a compensation block (305) and a ray source (306).

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