Weld joint stress corrosion testing apparatus and method

Abstract

A weld joint stress corrosion testing apparatus and method. The testing apparatus comprises a fixture (100), a test piece (200), a fixed part (300) and a moving part (400); the fixture (100) comprises a first end wall (110) and a second end wall (120) which are oppositely arranged; the test piece (200) is arranged between the first end wall (110) and the second end wall (120); the test piece (200) is of an inverted arch structure, and the bottom of the inverted arch structure is a weld joint testing area; the fixed part (300) is arranged on the side of the first end wall (110) facing the second end wall (120); and the moving part (400) is arranged on the second end wall (120) and used for applying pressure to the test piece (200) so that two ends of the inverted arch structure are clamped between the fixed part (300) and the moving part (400). In the testing apparatus, a fixed-point stress corrosion test can be performed on a weld spot of the test piece (200), and targeted evaluation can be performed on the stress corrosion status of the test piece (200), so as to avoid stress corrosion cracking of a welded piece during use.

Description

A welded joint stress corrosion testing device and testing method TECHNICAL FIELD

[0001] The present application relates to the field of stress corrosion, in particular to a welded joint stress corrosion testing device and testing method. BACKGROUND

[0002] Stress corrosion refers to the failure phenomenon of materials, mechanical parts or components under the combined action of static stress (mainly tensile stress) and corrosion, which is widespread in industrial equipment, is the result of the combined action of material stress and corrosive medium, and is one of the main causes of component failure. Stress corrosion has no obvious signs, but often brings disastrous results to engineering, further causing huge losses to industrial production and national economy.

[0003] Metal material welded components have the possibility of stress corrosion cracking or rupture in stress (especially tensile stress) and specific environmental medium, which will bring great safety hazards to the use of the components. Therefore, it is necessary to provide a welded joint stress corrosion testing device and testing method to test the corrosion resistance of the welded component under stress working condition. SUMMARY

[0004] In view of the above shortcomings of the prior art, the present application provides a welded joint stress corrosion testing device and testing method to test the corrosion resistance of the welded component under stress working condition.

[0005] To achieve the above object and other related objects, the present application provides a welded joint stress corrosion testing device, which comprises a clamp, a test piece, a fixed part and a moving part. The clamp comprises a first end wall and a second end wall arranged opposite to each other; the test piece is arranged between the first end wall and the second end wall, and the test piece is in an inverted arch structure, the bottom of the inverted arch structure being a welded joint test area; the fixed part is arranged on the side of the first end wall facing the second end wall; and the moving part is arranged on the second end wall to apply pressure to the test piece, so that the two ends of the inverted arch structure are clamped between the fixed part and the moving part.

[0006] In an example of the present application, the moving part comprises a sliding block, a fixed part and a moving part, the fixed part being fixedly arranged on the side of the second end wall away from the first end wall, the moving part being movable along the axial direction of the fixed part, and the sliding block being reciprocally slidable on the second end wall in the direction towards the first end wall, the moving part abutting against the sliding block through the fixed part.

[0007] In an example of the present application, the second end wall is provided with a positioning hole for the movement of the moving piece on the side away from the first end wall, and the second end wall is provided with a guide groove matched with the sliding block on the side towards the first end wall, the positioning hole is in communication with the guide groove, and the center of the guide groove is coaxial with the center of the positioning hole.

[0008] In an example of the present application, the number of test pieces is multiple, and adjacent test pieces are fixedly connected through connecting pieces.

[0009] In an example of the present application, the side of the fixed part, the connecting piece and the sliding block connected with the test piece is provided with a groove matched with the test piece, and the surface of the groove is provided with an insulating coating.

[0010] In an example of the present application, the test piece comprises a first connecting part, a second connecting part, a first stress part and a second stress part, the first stress part and the second stress part are oppositely arranged, one end of the first connecting part is fixedly connected with one end of the first stress part, the other end of the first connecting part is fixedly connected with one end of the second connecting part, and the other end of the second connecting part is fixedly connected with the second stress part; the first connecting part is integrally formed with the first stress part, the second connecting part is integrally formed with the second stress part, the first connecting part is welded with the second connecting part, the connection between the first connecting part and the second connecting part is a welded joint test area, the first stress part and the second stress part are symmetrical about the welded joint test area, and the thickness of the test piece uniformly increases from the welded joint test area to both sides.

[0011] In an example of the present application, the inner arc radius of the inverted arch structure is smaller than the outer arc radius of the inverted arch structure, the center a of the outer arc is located above the center b of the inner arc, and the center a and the center b are located on the same vertical axis.

[0012] In an example of the present application, the inner arc is a semicircle, and the stress surfaces of the first stress part and the second stress part are symmetrical about the line connecting the two endpoints of the inner arc.

[0013] The present application also provides a welding joint stress corrosion test method, comprising the following steps:

[0014] Providing a test device;

[0015] Measuring the parameters of the test piece;

[0016] Moving the moving part towards the test piece, and calculating the stress value of the welding joint test area according to the deformation amount of the test piece and the parameters of the test piece;

[0017] The testing device was placed in a test solution to perform a stress corrosion test.

[0018] The testing device includes a clamp, a test piece, a fixing part, and a moving part. The clamp includes a first end wall and a second end wall disposed opposite to each other. The test piece is disposed between the first end wall and the second end wall, and the test piece has an inverted arch structure. The bottom of the inverted arch structure is the weld joint test area, and the thickness of the test piece increases uniformly from the weld joint test area to both sides. The fixing part is disposed on the side of the first end wall facing the second end wall. The moving part is disposed on the second end wall and can apply pressure to the test piece. In one example of the present invention, the stress calculation formula for the weld joint test area is: Where, f: stress in the test area of ​​the welded joint; R1: radius of the inner arc; R2: radius of the outer arc; W: deformation value of the test piece; E: elastic modulus of the test piece material; δ: thickness of the test area of ​​the welded joint; α: correction coefficient.

[0019] The stress corrosion testing device for welded joints provided by this invention uses an inverted arch structure as the test piece, with the bottom of the inverted arch structure serving as the welded joint test area. During testing, the two ends of the inverted arch structure of the test piece are clamped between the fixed and movable parts by relative movement of the fixed and movable parts. By adjusting the position of the movable part, different pressures can be applied to the test piece to generate corresponding stresses in the welded joint test area. This enables targeted stress corrosion testing at the welded joint of welded components, providing a targeted assessment of the stress corrosion condition of the welded components. This further prevents stress corrosion cracking of welded components after service, improves the service life and efficiency of welded components, and indirectly enhances the reliability of welded equipment operation and personnel safety. Furthermore, in this application, the test piece is set as an inverted arch structure, and the fixed and movable parts compress the two ends of the bottom of the inverted arch structure. Under the compressive force, the inverted arch structure tends to bend, which generates tensile stress in the welded joint test area of ​​the inverted arch structure, enabling testing of the welded joint under tensile stress, with unexpected effects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 is a schematic diagram of the structure of the welded joint stress corrosion testing device of the present invention in one embodiment;

[0022] Figure 2 is a cross-sectional view of the welded joint stress corrosion testing device of the present invention in one embodiment;

[0023] Figure 3 is a schematic diagram of the structure of the test piece in one embodiment of the stress corrosion testing device for welded joints of the present invention;

[0024] Figure 4 is a front view of the test piece in one embodiment of the stress corrosion testing device for welded joints of the present invention;

[0025] Figure 5 is a physical image of a test piece in one embodiment of the stress corrosion testing device for welded joints of the present invention;

[0026] Figure 6 is a flowchart of one embodiment of the stress corrosion testing method for welded joints of the present invention;

[0027] Figure 7 shows the crack morphology of the test piece after testing in one embodiment of the stress corrosion testing method for welded joints of the present invention.

[0028] Figure 8 is a comparison diagram of calculated stress and measured stress in one embodiment of the stress corrosion test method for welded joints of the present invention.

[0029] Component designation explanation

[0030] 100, Fixture; 110, First end wall; 120, Second end wall; 130, Connecting plate; 200, Test piece; 210, Welded joint test area; 220, First connecting part; 230, Second connecting part; 240, First force-bearing part; 241, Force-bearing surface; 250, Second force-bearing part; 300, Fixing part; 310, Groove; 400, Moving part; 410, Sliding block; 420, Fixing component; 430, Moving component; 440, Positioning hole; 450, Guide groove; 500, Connecting component. Detailed Implementation

[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0032] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as part of the scope of the invention.

[0033] When two base materials are welded, a weld joint is formed at the junction. The weld joint typically includes key areas such as the fusion zone, heat-affected zone, fusion line, weld root, weld defects, and post-heat treatment zone. These areas are crucial for evaluating the weld quality and performance of the welded component. However, existing technologies cannot perform targeted stress corrosion testing on each area of ​​the weld joint. Therefore, this application provides a stress corrosion testing device for weld joints, which can use each area of ​​the weld joint as a test area to achieve targeted stress corrosion testing on each area of ​​the weld joint.

[0034] Referring to Figures 1 to 5, the stress corrosion testing device for welded joints provided by this invention includes a clamp 100, a test piece 200, a fixing part 300, and a moving part 400. The test piece 200 has an inverted arch structure, with the bottom of the inverted arch structure serving as the welded joint test area 210. During testing, the two ends of the inverted arch structure of the test piece 200 are clamped between the fixing part 300 and the moving part 400 by relative movement of the fixing part 300 and the moving part 400. By adjusting the position of the moving part 400, different pressures can be applied to the test piece 200, generating corresponding stresses in the welded joint test area 210. The testing device of this application, by using different areas of the welded joint as the bottom of the inverted arch structure during testing, can perform targeted stress corrosion tests on each area of ​​the welded joint of the test piece 200, providing a targeted assessment of the stress corrosion condition of the test piece 200 and preventing stress corrosion cracking of the welded joint after service.

[0035] Referring to Figures 1 and 2, in one embodiment, the fixture 100 includes a first end wall 110 and a second end wall 120 disposed opposite to each other, and the test piece 200 is disposed between the first end wall 110 and the second end wall 120. Further, the fixture 100 also includes a connecting plate 130 for fixing the first end wall 110 and the second end wall 120. The connecting plate 130 is disposed at the bottom of the first end wall 110 and the second end wall 120, with one end of the connecting plate 130 fixedly connected to the bottom of the first end wall 110 and the other end of the connecting plate 130 fixedly connected to the bottom of the second end wall 120. The connection method between the connecting plate 130 and the first end wall 110 and the second end wall 120 includes, but is not limited to, welding. The dimensions of the fixture 100 are not limited here and can be adapted according to actual needs.

[0036] Referring to Figures 1 and 2, in one embodiment, the fixing part 300 is disposed on the side of the first end wall 110 facing the second end wall 120. The connection between the fixing part 300 and the first end wall 110 includes, but is not limited to, welding. The moving part 400 is disposed on the second end wall 120 to apply pressure to the test piece 200, so that the two ends of the inverted arch structure are clamped between the fixing part 300 and the moving part 400. Furthermore, adjusting the distance between the fixing part 300 and the moving part 400 can adjust the pressure on the test piece 200 and generate corresponding stress in the weld joint test area 210 of the test piece 200.

[0037] Referring to Figures 1 and 2, in one embodiment, the moving part 400 includes a sliding block 410, a fixing member 420, and a moving member 430. The fixing member 420 is fixedly disposed on the side of the second end wall 120 opposite to the first end wall 110, and the moving member 430 can move axially along the fixing member 420. The connection between the fixing member 420 and the second end wall 120 includes, but is not limited to, welding. The sliding block 410 can slide on the second end wall 120 in a direction toward or away from the first end wall 110, and the moving member 430 passes through the fixing member 420 and abuts against the sliding block 410. In this embodiment, the fixing member 420 is a nut, and the moving member 430 is a bolt that matches the nut. The bolt and nut are threadedly connected. Rotating the bolt allows the bolt to move axially along the nut. By controlling the bolt to move toward the test piece 200, the sliding block 410 is pushed toward the fixing part 300 to apply pressure to the test piece 200. The magnitude of the applied pressure is adjusted by the movement distance of the bolt. In other embodiments, the fixing member 420 and the moving member 430 can also be other structures, such as the moving member 430 being a cylinder, hydraulic cylinder or lead screw assembly, as long as the moving member 430 can press the test piece 200 and fix the position of the moving member 430 after pressing.

[0038] Furthermore, in this embodiment, the second end wall 120 has a positioning hole 440 on the side facing away from the first end wall 110 for the movable member 430 to move, and a guide groove 450 matching the sliding block 410 is provided on the side of the second end wall 120 facing the first end wall 110. The positioning hole 440 communicates with the guide groove 450, and the center of the guide groove 450 is coaxial with the center of the positioning hole 440. The sliding block 410 is disposed in the guide groove 450, which can limit the torsion of the sliding block 410 and avoid the test piece 200 from being affected by the torsion.

[0039] Referring to Figure 2, in one embodiment, both the fixing part 300 and the sliding block 410 have grooves 310 that match the test piece 200 on the side facing the test piece 200. These grooves 310 not only support the test piece 200 but also prevent unexpected displacement of the test piece 200 during pressure application, thus avoiding amplified experimental data errors. Furthermore, the surface of the grooves 310 is provided with an insulating coating to prevent galvanic corrosion between the test piece 200 and the fixing part 300 and the sliding block 410.

[0040] The number of test pieces 200 in this application is not limited; it can be one, two, or more, as long as they are arranged and clamped between the fixed part 300 and the moving part 400 under the compression of the fixed part 300 and the moving part 400. Referring to Figures 1 and 2, in this embodiment, the testing device includes three test pieces 200, enabling simultaneous testing of all three. The three test pieces 200 are arranged along the compression direction of the moving part 400, and adjacent test pieces 200 are fixedly connected by connectors 500, which greatly improves testing efficiency. It should be noted that when there are multiple test pieces 200, considering the force transmission, the stress on each test piece 200 is basically the same. Therefore, the stress generated in each weld joint test area 210 is also the same, facilitating the selection and comparison of test pieces 200 under unified testing conditions. This eliminates the error of testing multiple test pieces 200 individually, ensuring that the testing conditions of multiple test pieces 200 are the same, thus facilitating better selection and comparison. For example, multiple test pieces 200 can be used to designate the fusion zone, heat-affected zone, and weld root as test areas 210 of the welded joint, respectively. This allows for comparison of stress corrosion in these areas under the same test conditions, resulting in more reliable test results that reflect the differences in stress corrosion performance across different areas of the welded joint. If it is necessary to compare stress corrosion in the same area of ​​the welded joint under different stress conditions, only one test piece 200 can be tested, eliminating the need for the connector 500.

[0041] Furthermore, both sides of the connector 500 are provided with grooves 310 for supporting and fixing the test piece 200. The size of the grooves 310 matches the size of the test piece 200, and the surface of the grooves 310 is provided with an insulating coating to prevent galvanic corrosion between the test piece 200 and the connector 500. Furthermore, in order to improve the accuracy of the test, the grooves 310 are milled.

[0042] Referring to Figures 1 to 5, in one embodiment, the test piece 200 includes a first connecting portion 220, a second connecting portion 230, a first force-bearing portion 240, and a second force-bearing portion 250. The first force-bearing portion 240 and the second force-bearing portion 250 are disposed opposite to each other and are fixedly connected by the first connecting portion 220 and the second connecting portion 230. The first connecting portion 220 and the second connecting portion 230 combine to form an inverted arch structure. Specifically, one end of the first connecting portion 220 is fixedly connected to one end of the first force-bearing portion 240, the other end of the first connecting portion 220 is fixedly connected to one end of the second connecting portion 230, and the other end of the second connecting portion 230 is fixedly connected to the second force-bearing portion 250. The first connecting portion 220 and the first force-bearing portion 240 are integrally formed, the second connecting portion 230 and the second force-bearing portion 250 are integrally formed, and the first connecting portion 220 and the second connecting portion 230 are welded together. The connection point between the first connecting portion 220 and the second connecting portion 230 is the weld joint test area 210. The first force-bearing portion 240 and the second force-bearing portion 250 are symmetrical about the weld joint test area 210, and the thickness of the test piece 200 increases uniformly from the weld joint test area 210 to both sides. This ensures that when the first force-bearing portion 240 and the second force-bearing portion 250 are compressed, the weld joint test area 210 is the area of ​​maximum stress and has a large stress gradient. For example, the thickness of the weld joint test area 210 is 2~5mm. For example, the thickness of the weld joint test area 210 can be 2mm, 3mm, 4mm or 5mm.

[0043] Referring to Figures 1 to 4, in one embodiment, the radius of the inner arc of the inverted arch structure is smaller than the radius of the outer arc of the inverted arch structure. The center a of the outer arc is located above the center b of the inner arc, and centers a and b are located on the same vertical axis. The inner arc is a semicircle, and the force-bearing surfaces 241 of the first force-bearing part 240 and the second force-bearing part 250 are symmetrical about the line connecting the two ends of the inner arc, so that the force on the test piece 200 is on the line connecting the two ends of the inner arc, ensuring the stability of the test piece 200 during the force application process. The distance l between centers a and b is adaptively adjusted according to experimental requirements. For example, the distance l between centers a and b is 2 mm. In other embodiments, the distance l between centers a and b can also be other values.

[0044] Please refer to Figures 1 to 7. The present invention also provides a method for testing stress corrosion of welded joints, comprising the following steps:

[0045] S1. Provide testing equipment;

[0046] S2. Measure the parameters of test piece 200;

[0047] S3. Move the moving part 400 toward the test piece 200, and calculate the stress value of the weld joint test area 210 based on the deformation and parameters of the test piece 200.

[0048] S4. Place the test device in the test solution to perform stress corrosion test.

[0049] In step S1, the testing device includes a clamp 100, a test piece 200, a fixing part 300, and a moving part 400. The clamp 100 includes a first end wall 110 and a second end wall 120 disposed opposite to each other; the test piece 200 is disposed between the first end wall 110 and the second end wall 120, and the test piece 200 has an inverted arch structure, with the bottom of the inverted arch structure being the weld joint test area 210, and the thickness of the test piece 200 increasing uniformly from the weld joint test area 210 to both sides; the fixing part 300 is disposed on the side of the first end wall 110 facing the second end wall 120; the moving part 400 is disposed on the second end wall 120 and can apply pressure to the test piece 200.

[0050] In one embodiment, two base materials are welded together to form a welded component. The welded component is then processed into an inverted arch structure, and the test area of ​​the weld joint is located at the bottom of the inverted arch structure as the weld joint test area 210. For example, if stress corrosion of the heat-affected zone is being tested, the heat-affected zone is placed at the bottom of the inverted arch structure as the weld joint test area 210. In other embodiments, the testing device further includes a connector 500. If it is necessary to compare the stress corrosion of different areas of the weld joint, the same welded component is processed into multiple test pieces 200, and different areas of the weld joint are respectively placed at the bottom of the inverted arch structure as weld joint test areas 210. During testing, the test pieces 200 are arranged along the pressing direction of the moving part 400, and adjacent test pieces 200 are fixedly connected by the connector 500 to connect the weld joint test areas 210 of the multiple test pieces 200. For example, stress corrosion point testing can be performed simultaneously on the fusion zone, heat-affected zone, and weld root of the weld joint to compare the differences in stress corrosion performance of different areas of the weld joint under the same test conditions.

[0051] In step S2, the parameters of the test piece 200 include: the inner arc radius R1, the outer arc radius R2, the distance l between the outer arc center a and the inner arc center b, and the thickness δ of the weld joint test area 210.

[0052] In step S3, the moving part 400 includes a sliding block 410, a fixing member 420, and a moving member 430. The fixing member 420 is fixedly disposed on the side of the second end wall 120 opposite to the first end wall 110, and the moving member 430 can move axially along the fixing member 420. The sliding block 410 can slide back and forth on the second end wall 120 in the direction toward the first end wall 110, and the moving member 430 passes through the fixing member 420 and abuts against the sliding block 410. A positioning hole 440 for the moving member 430 to move is provided on the side of the second end wall 120 opposite to the first end wall 110, and a guide groove 450 matching the sliding block 410 is provided on the side of the second end wall 120 toward the first end wall 110. The positioning hole 440 communicates with the guide groove 450, and the center of the guide groove 450 is coaxial with the center of the positioning hole 440.

[0053] In one embodiment, the fixing member 420 is a nut, and the moving member 430 is a bolt that matches the nut. The bolt and nut are threaded together. Rotating the bolt allows it to move axially along the nut. By controlling the displacement of the bolt, the sliding block 410 slides toward the first end wall 110 to apply different pressures to the test piece 200. The deformation W of each test piece 200 can be calculated using the bolt displacement S and the number of test pieces 200 n, i.e., W = S / n.

[0054] Furthermore, the stress magnitude in the test area 210 of the welded joint of test piece 200 is obtained according to the stress calculation formula. The stress calculation formula is as follows: Where f: stress at the weld joint test area 210; R1: inner arc radius; R2: outer arc radius; W: deformation value of test piece 200; E: material elastic modulus of test piece 200; δ: thickness of weld joint test area 210; α: correction coefficient. Furthermore, the correction coefficient α is related to the distance l between the center a and center b of the inverted arch structure. For example, the distance l between center a and center b is 2 mm, and the formula for calculating the correction coefficient α is as follows: Here, R is the average of the inner and outer arc radii of the inverted arch structure.

[0055] In step S4, following the standard method of YB / T 5362-2006, the testing apparatus is suspended in a conical flask containing a thermometer and a magnesium chloride solution to conduct a boiling magnesium chloride stress corrosion test on the test piece 200. The solution temperature is controlled at 155±1℃, and the test time is 2 hours. After the test, the test piece 200 is removed, cleaned, dried, and its fracture condition is observed under a microscope. For example, the test piece 200 is made of stainless steel.

[0056] Please refer to Figures 5 to 8. To verify the accuracy of the testing device in this application, a testing device was prepared, and the stress value of the weld joint test area 210 was calculated and compared with the actual stress value. Specifically, the selected testing device includes a test piece 200 with an inner arc radius of 30 mm, an outer arc radius of 34 mm, a distance l between the centers of the inner and outer arcs of 2 mm, a thickness of 2 mm for the weld joint test area 210, and the material of the test piece 200 being 304 stainless steel. Before testing, the weld joint test area 210 was smoothed with 1200-grit sandpaper, and strain gauges were attached to the weld joint test area 210. The test piece 200 was clamped on a matching fixture 100, and then the position of the moving part 430 was adjusted within the elastic range of the test piece 200 to apply different levels of pressure to the test piece 200. The process was repeated multiple times, measuring the displacement of the moving part 430 each time. The stress in the welded joint test area 210 was calculated using the stress calculation formula of this application. The actual strain value of the test piece 200 was detected using strain gauges, and the actual stress value was calculated based on Hooke's Law using the actual strain value of the test piece 200. The calculated stress value was compared with the actual stress value calculated using Hooke's Law, and the deviation between the calculated and actual stress values ​​was found to be within 5%. Therefore, the testing device of this application can accurately calculate the stress value in the welded joint test area 210, enabling targeted testing of welded components and ensuring the accuracy and traceability of the test.

[0057] The stress corrosion testing device for welded joints provided by this invention uses an inverted arch structure as the test piece, with the bottom of the inverted arch structure serving as the welded joint test area. During testing, the two ends of the inverted arch structure of the test piece are clamped between the fixed and movable parts by relative movement of the fixed and movable parts. By adjusting the position of the movable part, different pressures can be applied to the test piece to generate corresponding stresses in the welded joint test area. This enables targeted stress corrosion testing of different areas of the welded joint of the welded component, allowing for a targeted assessment of the stress corrosion condition of the welded component. This further prevents stress corrosion cracking of the welded component after service, improves the service life and efficiency of the welded component, and indirectly enhances the reliability of the welded component equipment and personnel safety. Furthermore, in this application, the test piece is set as an inverted arch structure, and the bottom ends of the inverted arch structure are compressed by the fixed and movable parts. Under the compression force, the inverted arch structure tends to bend, which generates tensile stress in the welded joint test area of ​​the inverted arch structure, enabling testing of the welded joint under tensile stress, with unexpected effects. Furthermore, the testing apparatus of this application greatly simplifies the stress corrosion testing process for welded joints. Using the testing method of this application, only the displacement value of the moving part needs to be measured to calculate the stress value, facilitating the corrosion evaluation of the welded joint. Therefore, this invention effectively overcomes some practical problems in the prior art, thus possessing high utilization value and practical significance.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A welded joint stress corrosion testing apparatus, characterized by, The utility model relates to a test device for welding joint, comprising: a clamp comprising a first end wall and a second end wall arranged oppositely; a test piece arranged between the first end wall and the second end wall, the test piece being a reverse arch structure, the bottom of the reverse arch structure being a welding joint test area; a fixed part arranged on a side of the first end wall facing the second end wall; a moving part arranged on the second end wall to apply pressure to the test piece so that both ends of the reverse arch structure are clamped between the fixed part and the moving part.

2. The test device of claim 1, wherein, The moving part comprises a sliding block, a fixed part and a moving part, the fixed part being fixedly arranged on a side of the second end wall away from the first end wall, the moving part being movable along the axial direction of the fixed part, and the sliding block being reciprocally slidable on the second end wall in a direction towards the first end wall, the moving part abutting against the sliding block through the fixed part.

3. The test device of claim 2, wherein, A positioning hole for the movement of the moving part is arranged on a side of the second end wall away from the first end wall, a guide groove matching the sliding block is arranged on a side of the second end wall facing the first end wall, the positioning hole is in communication with the guide groove, and the center of the guide groove is coaxial with the center of the positioning hole.

4. The test device of claim 2, wherein, The number of test pieces is multiple, and adjacent test pieces are fixedly connected through connecting pieces.

5. The test device of claim 4, wherein, The side of the fixed part, the connecting pieces and the sliding block connected with the test pieces are each provided with a groove matching the test pieces, and the surface of the groove is provided with an insulating coating.

6. The test device of claim 1, wherein, The test piece comprises a first connecting part, a second connecting part, a first stress receiving part and a second stress receiving part, the first stress receiving part and the second stress receiving part are arranged oppositely, one end of the first connecting part is fixedly connected with one end of the first stress receiving part, the other end of the first connecting part is fixedly connected with one end of the second connecting part, and the other end of the second connecting part is fixedly connected with the second stress receiving part; the first connecting part is integrally formed with the first stress receiving part, the second connecting part is integrally formed with the second stress receiving part, the first connecting part is welded with the second connecting part, the connection between the first connecting part and the second connecting part is a welding joint test area, the first stress receiving part and the second stress receiving part are symmetrical about the welding joint test area, and the thickness of the test piece uniformly increases from the welding joint test area to both sides.

7. The test device of claim 1, wherein, The inner arc radius of the reverse arch structure is smaller than the outer arc radius of the reverse arch structure, the center a of the outer arc is located above the center b of the inner arc, and the center a and the center b are located on the same vertical axis.

8. The test device of claim 7, wherein, The inner arc is a semicircle, and the stress receiving surfaces of the first stress receiving part and the second stress receiving part are symmetrical about the line connecting the two endpoints of the inner arc.

9. A method of stress corrosion testing of a welded joint, characterized by The utility model relates to a test device for welding joint, comprising: providing a test device; measuring the parameters of a test piece; moving the moving part towards the test piece, calculating the stress value of the welding joint test area according to the deformation amount of the test piece and the parameters of the test piece; placing the test device in a test solution for stress corrosion testing; The test device comprises a clamp, a test piece, a fixing part and a moving part; the clamp comprises oppositely arranged first and second end walls; the test piece is arranged between the first and second end walls, and has an inverted arch structure, the bottom of the inverted arch structure being a welded joint test area; the fixing part is arranged on the side of the first end wall facing the second end wall; and the moving part is arranged on the second end wall to apply pressure to the test piece, so that the two ends of the inverted arch structure are clamped between the fixing part and the moving part.

10. The test method of claim 9, wherein, The stress calculation formula of the welded joint test area is: , Wherein, f: stress of the welded joint test area; R1: inner arc radius; R2: outer arc radius; W: deformation value of the test piece; E: material elastic modulus of the test piece; δ: thickness of the welded joint test area; α: correction coefficient.

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