Creep performance test system and service life prediction method for lap joint type low-melting-point brazing element

Abstract

The invention is suitable for the field of welding testing, and discloses a creep property testing system and a service life prediction method for a lap joint type low-melting-point brazing element. Comprising a high-temperature environment box, a temperature control module used for controlling the temperature in the high-temperature environment box, a loading control module used for applying a tensile load to a sample, a sample clamping module used for clamping the edges of the two sides of a weld joint of the sample, and a displacement detection module used for detecting the creep degree of the sample. Wherein the loading control modules are arranged at the two ends of the high-temperature environment box, the loading control modules are connected with the sample clamping modules respectively, and the sample clamping modules are connected to the displacement detection modules respectively.

Description

Technical Field

[0001] The invention relates to the field of welding testing, and in particular to a creep performance testing system and a life prediction method for an overlapping low-melting-point brazing element. Background Art

[0002] One of the main design concepts of the third-generation advanced pressurized water reactor is to use passive measures to achieve safety control during the operation of nuclear power units. Temperature sensitive components based on lap soldering are widely used in the passive safety protection system of my country's third-generation pressurized water reactor. Accurate characterization of material creep performance is the prerequisite for life analysis and environmental suitability evaluation of soldered structures. The lap brazed joint contains multiple complex regions such as the base material, diffusion zone, and brazing material. The mechanical properties of each region of the brazed joint are different. The pinning effect of the brazing diffusion zone is the main factor in maintaining the high-temperature strength of the soldered component. Conventional uniaxial tests cannot accurately characterize the high-temperature creep performance of the lap brazed joint component. The test specimen is two metal plates lap-welded together, and the lap joint is brazed. At present, the creep detection equipment is basically clamped and fixed at both ends of the lapped metal plate. When tensile loading is performed, it is easy to cause metal deformation and errors, and the creep performance cannot be accurately measured. Summary of the invention

[0003] The technical problem to be solved by the present application is to provide a creep performance testing system and a life prediction method for overlapping low-melting-point brazing components.

[0004] The technical solution adopted by the present application to solve its technical problems is: a high-temperature environmental box, a temperature control module for controlling the temperature inside the high-temperature environmental box, a loading control module for applying a tensile load to the sample, a sample clamping module for clamping the edges on both sides of the weld of the sample, and a displacement detection module for detecting the creep degree of the sample; wherein the loading control module is arranged at both ends of the high-temperature environmental box, the loading control module is respectively connected to the sample clamping module, and the sample clamping module is respectively connected to the displacement detection module.

[0005] In one embodiment, the sample clamping module includes a first clamping unit and a second clamping unit, the first clamping unit includes a first fixed seat, a first connecting member and a first movable member, the second clamping unit includes a second fixed seat, a second connecting member and a second movable member, the first fixed seat and the second fixed seat are respectively connected to both sides of the sample, the first connecting member and the first movable member are clamped on one side close to the welding part of the sample, and the second connecting member and the second movable member are clamped on the other side close to the welding part of the sample.

[0006] In one embodiment, the sample clamping module is provided with a locking member and a fixing member, the fixing member clamps the displacement detection module on the first connecting member and the second connecting member, and the fixing member is locked by the locking member.

[0007] In one embodiment, the first fixing seat and the second fixing seat include a clamp, an axle and a clamping mechanism, the upper end of the clamp is connected to the loading control module, the lower end of the clamp is provided with a groove, the clamping mechanism is arranged in the groove, the clamping mechanism is connected to the first connecting member and the second connecting member, and the axle hinges the clamping mechanism and the clamp.

[0008] In one embodiment, the clamping mechanism includes a clamping seat, a clamping block and a clamping bolt, the clamping seat is hinged to the clamp, the clamping seat abuts against the sample, the clamping block clamps the sample on the clamping seat, and the clamping bolt passes through the clamping block and the sample and is threadedly fixed to the clamping seat.

[0009] In one embodiment, the loading control module includes a loading control module and a load controller, the loading control module is arranged in the high temperature environment box, and the load sensor is connected to the loading control module; the loading control module includes an upper loading rod and a lower loading rod, the upper loading rod is fixed in the high temperature environment box, and the lower loading rod is connected to the load controller.

[0010] In one embodiment, the displacement detection module includes a first displacement extension rod, a second displacement extension rod and an extensometer, the first displacement extension rod is connected to the first clamping unit, the second displacement extension rod is connected to the second clamping unit, and the first displacement extension rod and the second displacement extension rod are connected to the extensometer.

[0011] In one embodiment, the displacement detection module also includes a positioner, which includes a frame, a positioning member and an adjustment bolt. The frame is connected to the lower loading rod, and the positioning block extends outward from both sides of the frame. The positioning block is provided with a positioning groove parallel to the first extension rod and the second extension rod. The first extension rod and the second extension rod pass through the positioning groove. The positioning block is provided with a positioning threaded hole parallel to the length direction of the positioning groove. The adjustment bolt passes through the positioning threaded hole and abuts against the first extension rod and the second extension rod.

[0012] The present application also provides a method for predicting the creep life of an overlapped low-melting-point brazing component, comprising the following steps:

[0013] Step S1, determining the material of the component to be evaluated, the component working temperature T, in °C and the working load P, in N, the brazing layer width a, in mm, the brazing layer length b, in mm, the brazing layer thickness s, in mm and the porosity A of the solder layer, in %;

[0014] Step S2, placing the sample into the high temperature environment box, fixing and connecting the two ends of the sample respectively through the loading control module and applying stress F, in N, clamping the edges of the weld on both sides of the sample through the sample clamping module, and using the displacement detection module to detect the creep deformation δ, in mm;

[0015] Step S3, by substituting the parameters of step S1 and the stress F and the creep deformation δ obtained in step S2 into the equation, the initial creep stress is calculated using the component shear stress τ in units of MPa and the creep strain is calculated using the component shear strain γ, which are dimensionless parameters;

[0016] Step S4, forming a linear relationship between the brazing layer shear stress τ obtained in step 3 and the creep rupture time t(h), and a linear relationship between the brazing layer shear stress and the minimum creep shear strain rate A linear relationship in a logarithmic coordinate system is formed, and it is determined whether the two relationship curves conform to a linear relationship in the double logarithmic coordinate system. If both conform to a linear relationship, the next step S5 is continued;

[0017] Step S5, for the overlapped brazed component subjected to shear deformation that satisfies the linear relationship in the double logarithmic coordinates in step 4, determine the service life of the overlapped brazed component subjected to shear deformation under the specified working load P, and the service life can be obtained through the formula.

[0018] In one embodiment, the formula in step 3 is

[0019] Wherein, F is the initial creep load during the creep test, in N, a is the width of the brazing layer, in mm, b is the length of the brazing layer, in mm, s is the thickness of the brazing layer, in mm, A is the porosity of the brazing layer, and is the shear creep deformation of the brazing layer during the creep test, in mm.

[0020] The implementation of the present application is a lap-jointed low-melting-point brazing component creep performance testing system, which has the following beneficial effects: the edge of the sample weld is clamped by a sample clamping module, rather than clamped at both ends of the sample, which can greatly reduce the influence of the deformation of the metal at both ends of the sample on the sample result, and then by heating in a high-temperature environment box, the loading control module applies tensile force to both ends of the sample, and the displacement detection module detects the creep deformation.

[0021] The implementation of the present application of a method for predicting the creep life of an overlapped low-melting-point brazing component has the following beneficial effects: first, the various parameters of the sample are detected and confirmed, and then calculations are performed according to the formula to obtain the working life of the sample under a working environment of a corresponding temperature and a corresponding tensile load, and the detection data does not need to screen excess data under a creep performance test system for overlapped low-melting-point brazing components, and the creep deformation directly detected is true and reliable, which greatly simplifies the working life calculation process and improves the accuracy of working life estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present application, the present application will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show certain embodiments of the present application and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work. In the drawings:

[0023] Figure 1 It is an overall diagram of a creep performance testing system for an overlapping low-melting-point brazing element in one embodiment of the present invention;

[0024] Figure 2 1 is a front view of a creep performance testing system for an overlapping low-melting-point brazing element in one embodiment of the present invention;

[0025] Figure 3 It is a front view of a pattern fixing module of a lap-jointed low-melting-point brazing element creep performance testing system in one embodiment of the present invention;

[0026] Figure 4 It is a stereoscopic diagram of a pattern fixing module of a lap-jointed low-melting-point brazing component creep performance testing system in one embodiment of the present invention;

[0027] Figure 5 It is a cross-sectional view of a pattern fixing module of a lap-jointed low-melting-point brazing component creep performance testing system in one embodiment of the present invention;

[0028] Figure 6 yes Figure 1 A magnified image of point A;

[0029] Figure 7 It is a structural diagram of a creep performance testing system for overlapping low-melting-point brazing components in one embodiment of the present invention;

[0030] Figure 8 This is a step diagram of a method for predicting creep life of an overlapping low-melting-point brazing component in one embodiment of the present invention;

[0031] Fig. 9A creep life prediction method for an overlapped low-melting-point brazing component according to an embodiment of the present invention is a comparison diagram of creep test results at different initial stress levels;

[0032] Fig.10 A method for predicting creep life of an overlapped low-melting-point brazing component in one embodiment of the present invention is a comparison diagram of creep long-term test results at the same initial stress level;

[0033] Fig.11 The present invention is a method for predicting the creep life of an overlapped low-melting-point brazing component in one embodiment of the present invention, and a comparison diagram of short-time creep test results at different initial stress levels.

[0034] Reference numerals

[0035] 100, high temperature environment box; 200, loading control module; 210, upper loading rod; 220, lower loading rod; 300, first clamping unit; 301, clamp; 302, shaft; 303, clamping seat; 304, clamping block; 305, clamping bolt; 306, fixing member; 307, first movable member; 308, first connecting member; 309, locking member; 310, second clamping unit; 311, second movable member; 312, second connecting member; 400, extensometer; 401, frame; 402, positioning member; 403, adjusting bolt; 404, positioning groove; 405, calibration plate; 406, locking bolt; 410, first extension rod; 420, second extension rod; 500, test specimen; 510, weld. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0037] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0038] Figures 1 to 7 A lap-joint low-melting-point brazing component creep performance testing system in an embodiment of the present invention is shown. The lap-joint low-melting-point brazing component creep performance testing system can be used to perform creep performance testing on lap-joint brazing weldments, and may include a high-temperature environmental chamber 100, a temperature control module for controlling the temperature in the high-temperature environmental chamber 100, a loading control module 200 for applying a tensile load to a sample 500, a sample 500 clamping module for clamping the edges on both sides of a weld 510 of the sample 500, and a displacement detection module for detecting the creep degree of the sample 500; wherein the loading control module 200 is arranged at both ends of the high-temperature environmental chamber 100, the loading control module 200 is respectively connected to the sample 500 clamping module, and the sample 500 clamping module is respectively connected to the displacement detection module.

[0039] The edge of the weld 510 of the sample 500 is clamped by the sample 500 clamping module instead of clamping at both ends of the sample 500. This can greatly reduce the influence of the deformation of the metal at both ends of the sample 500 on the result of the sample 500. Then, by heating in the high-temperature environment box 100, the loading control module 200 applies tensile force to both ends of the sample 500, and the displacement detection module detects the creep deformation.

[0040] In a specific embodiment, the displacement detection module is disposed outside the high temperature environment box 100 to prevent high temperature from affecting the measurement accuracy of the displacement detection module.

[0041] In a specific embodiment, the high temperature environment box 100 is provided with a temperature detection unit and a heating unit. The temperature detection unit detects the temperature inside the high temperature environment box 100, and the heating unit heats the temperature inside the high temperature environment box 100. The heating unit is an electric heating element, and the electric heating element is connected to the temperature detection unit.

[0042] Figures 3 to 5 The sample 500 clamping module shown in one embodiment may include a first clamping unit 300 and a second clamping unit 310, wherein the first clamping unit 300 includes a first fixed seat, a first connecting member 308 and a first movable member 307, and the second clamping unit 310 includes a second fixed seat, a second connecting member 312 and a second movable member 311, the first fixed seat and the second fixed seat are respectively connected to both sides of the sample 500, the first connecting member 308 and the first movable member 307 are clamped on one side close to the welding part of the sample 500, and the second connecting member 312 and the second movable member 311 are clamped on the other side close to the welding part of the sample 500.

[0043] Figures 2 to 5 The sample 500 clamping module may include a locking member 309 and a fixing member 306 in one embodiment. The fixing member 306 clamps the displacement detection module on the first connecting member 308 and the second connecting member 312 , and the fixing member 306 is locked by the locking member 309 .

[0044] Figures 2 to 5 It is shown that the first fixing seat and the second fixing seat may include in one embodiment that the first fixing seat and the second fixing seat include a clamp 301, an axis rod 302 and a clamping mechanism, the upper end of the clamp 301 is connected to the loading control module 200, the lower end of the clamp 301 is provided with a groove, the clamping mechanism is arranged in the groove, the clamping mechanism is connected to the first connecting member 308 and the second connecting member 312, and the axis rod 302 hinges the clamping mechanism and the clamp 301.

[0045] Figures 2 to 5 The clamping mechanism shown in one embodiment may include a clamping seat 303, a clamping block 304 and a clamping bolt 305, wherein the clamping seat 303 is hinged to the clamp 301, the clamping seat 303 abuts against the sample 500, the clamping block 304 clamps the sample 500 on the clamping seat 303, and the clamping bolt 305 passes through the clamping block 304 and the sample 500 and is threadedly fixed to the clamping seat 303.

[0046] Figure 1 and Figure 2It is shown that the loading control module 200 may include a loading control module 200 and a load controller in one embodiment, wherein the loading control module 200 is disposed in the high temperature environment box 100, and the load sensor is connected to the loading control module 200; the loading control module 200 includes an upper loading rod 210 and a lower loading rod 220, wherein the upper loading rod 210 is fixed to the high temperature environment box 100, and the lower loading rod 220 is connected to the load controller.

[0047] Figure 1 and Figure 6 The displacement detection module shown in one embodiment may include a first displacement extension rod, a second displacement extension rod and an extensometer 400, wherein the first displacement extension rod is connected to the first clamping unit 300, the second displacement extension rod is connected to the second clamping unit 310, and the first displacement extension rod and the second displacement extension rod are connected to the extensometer 400.

[0048] In a specific embodiment, the extensometer 400 is a grating displacement extensometer 400. The grating displacement extensometer 400 has extremely high detection accuracy, with an error of up to ±1 μm, which meets the accuracy requirements of creep test.

[0049] Figure 1 and Figure 6 The displacement detection module shown in one embodiment may include a positioner, which includes a frame 401, a positioning member 402 and an adjusting bolt 403. The frame 401 is connected to the lower loading rod 220, and the positioning block extends outward from both sides of the frame 401. The positioning block is provided with a positioning groove 404 parallel to the first extension rod 410 and the second extension rod 420. The first extension rod 410 and the second extension rod 420 pass through the positioning groove 404. The positioning block is provided with a positioning threaded hole parallel to the length direction of the positioning groove 404. The adjusting bolt 403 passes through the positioning threaded hole and abuts against the first extension rod 410 and the second extension rod 420.

[0050] In a specific embodiment, the positioner further includes a locking screw, and the frame 401 is two semicircular ring-shaped clamps, and the clamps are locked on the lower loading rod 220 by the locking screw.

[0051] In a specific embodiment, a calibration piece 405 is provided at the joint between the first extension rod 410 and the second extension rod 420 and the extensometer 400. The area of ​​the calibration piece 405 is larger than the diameter of the first extension rod 410 and the second extension rod 420. This can ensure that the first extension rod 410 and the second extension rod 420 will not be misaligned with the detection end of the extensometer 400 due to position offset, resulting in mispickup, thereby improving the reliability of detection.

[0052] Figures 8 to 11 A method for predicting creep life of an overlapping low-melting-point brazing component in one embodiment of the present invention is shown, comprising the following steps:

[0053] Step S1, determining the material of the component to be evaluated, the component working temperature T, in °C and the working load P, in N, the brazing layer width a, in mm, the brazing layer length b, in mm, the brazing layer thickness s, in mm and the porosity A of the solder layer, in %;

[0054] Step S2, placing the sample 500 into the high temperature environment box 100, fixing and connecting the two ends of the sample 500 respectively through the loading control module 200 and applying stress F, in N, clamping the edges of the weld 510 of the sample 500 on both sides through the sample 500 clamping module, and using the displacement detection module to detect the creep deformation δ, in mm;

[0055] Step S3, by substituting the parameters of step S1 and the stress F and the creep deformation δ obtained in step S2 into the equation, the initial creep stress is calculated using the component shear stress τ in units of MPa, and the creep strain is calculated using the component shear strain γ, which are dimensionless parameters;

[0056] Step S4, forming a linear relationship between the brazing layer shear stress τ obtained in step 3 and the creep rupture time t(h), and a linear relationship between the brazing layer shear stress and the minimum creep shear strain rate A linear relationship in a logarithmic coordinate system is formed, and it is determined whether the two relationship curves conform to a linear relationship in the double logarithmic coordinate system. If both conform to a linear relationship, the next step S5 is continued;

[0057] Step S5, for the overlapped brazed component subjected to shear deformation that satisfies the linear relationship in the double logarithmic coordinates in step 4, determine the service life of the overlapped brazed component subjected to shear deformation under the specified working load P, and the service life can be obtained through the formula.

[0058] First, the various parameters of the sample are tested and confirmed, and then calculated according to the formula to obtain the working life of the sample under the working environment of the corresponding temperature and the corresponding tensile load. In addition, the test data does not need to be screened in the overlapped low-melting-point brazing component creep performance test system. The creep deformation directly detected is true and reliable, which greatly simplifies the working life calculation process and improves the accuracy of working life estimation.

[0059] The formula in step 3 is

[0060] Wherein, F is the initial creep load during the creep test (N), a is the width of the brazing layer (mm), b is the length of the brazing layer (mm), s is the thickness of the brazing layer (mm), A is the porosity of the brazing layer (which can be determined by the X-ray method), and is the shear creep deformation of the brazing layer during the creep test (mm).

[0061] The formula in step 5 is lg(t)=n+mlg(τ). The creep life of the component can be calculated by extrapolation through the formula, where τ is the shear stress of the brazing layer in MPa, t is the creep rupture time in h, and the parameters n and m can be fitted by the creep test results of the overlapped brazing component obtained by the experiment using the least squares method;

[0062] By transforming the formula, we can get the following formula:

[0063]

[0064] Where A IC It is the maximum allowable porosity of the overlap soldering component during the manufacturing process.

[0065] Fig.11 The comparative test results of the test system proposed in this application and the conventional creep displacement test results in the standard are shown. In the initial stage of the creep test (0.007 hours), the elastic displacement of the structure using the traditional displacement life prediction method is 0.149 mm, and the actual shear displacement of the brazing layer using the method proposed in this article is 0.012 mm. It can be seen that the measured displacement accuracy of the conventional creep displacement life prediction method is much lower than the test accuracy of the system proposed in this article. This is because the fixing method is different. In the existing standard, the two ends of the specimen need to be fixed with corresponding holes, and the specimens around the holes will be subjected to huge deformation. It is necessary to correct the initial creep parameters. This correction value is usually an empirical formula and is not accurate. However, because the present application is clamped on both sides of the weld for detection, the deformation is smaller, the result is more accurate, and no correction is required.

[0066] Fig. 9 It is shown that under different tensile forces, conventional existing technologies will have an additional deformation at the beginning compared to the present application, which requires removal or increase of correction values ​​in conventional samples, greatly affecting the test accuracy. As time goes on, creep is gradually destroyed, forming a fracture breakthrough, which is the final life of the brazing.

[0067] Fig.10 It is shown that under the same tensile force, a comparison is made, and it can be clearly seen that the previous conventional existing technology will have a much larger deformation.

[0068] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope covered by the claims of the present invention.

Claims

1. A creep performance testing system for overlapping low-melting-point brazing components, characterized in that: include: A high temperature environment box (100), a temperature control module for controlling the temperature in the high temperature environment box (100), a loading control module (200) for applying a tensile load to a sample (500), a sample (500) clamping module for clamping the edges of both sides of a weld (510) of the sample (500), and a displacement detection module for detecting the creep degree of the sample (500); The loading control module (200) is arranged at two ends of the high temperature environment box (100), the loading control module (200) is respectively connected to the sample (500) clamping module, and the sample (500) clamping module is respectively connected to the displacement detection module.

2. The creep performance testing system of overlapping low-melting-point brazing components according to claim 1, characterized in that: The sample clamping module comprises a first clamping unit (300) and a second clamping unit (310), wherein the first clamping unit (300) comprises a first fixed seat, a first connecting member (308) and a first movable member (307), and the second clamping unit (310) comprises a second fixed seat, a second connecting member (312) and a second movable member (311), wherein the first fixed seat and the second fixed seat are respectively connected to two sides of a sample (500), the first connecting member (308) and the first movable member (307) are clamped on one side close to a welding position of the sample (500), and the second connecting member (312) and the second movable member (311) are clamped on the other side close to a welding position of the sample (500).

3. The creep performance testing system of overlapping low-melting-point brazing components according to claim 2, characterized in that: The sample (500) clamping module is provided with a locking member (309) and a fixing member (306), wherein the fixing member (306) clamps the displacement detection module on the first connecting member (308) and the second connecting member (312), and the fixing member (306) is locked by the locking member (309).

4. The creep performance testing system of overlapping low melting point brazing components according to claim 2, characterized in that: The first fixing seat and the second fixing seat include a clamp (301), an axle (302) and a clamping mechanism. The upper end of the clamp (301) is connected to the loading control module (200). The lower end of the clamp (301) is provided with a groove. The clamping mechanism is arranged in the groove. The clamping mechanism is connected to the first connecting member (308) and the second connecting member (312). The axle (302) hinges the clamping mechanism and the clamp (301).

5. The creep performance testing system of overlapping low melting point brazing components according to claim 4, characterized in that: The clamping mechanism comprises a clamping seat (303), a clamping block (304) and a clamping bolt (305); the clamping seat (303) is hinged to the clamp (301); the clamping seat (303) abuts against the sample (500); the clamping block (304) clamps the sample (500) on the clamping seat (303); and the clamping bolt (305) passes through the clamping block (304) and the sample (500) and is threadedly fixed to the clamping seat (303).

6. The creep performance testing system of overlapping low-melting-point brazing components according to claim 1, characterized in that: The loading control module (200) comprises a loading control module (200) and a load controller; the loading control module (200) is arranged in the high temperature environment box (100); the load sensor is connected to the loading control module (200); the loading control module (200) comprises an upper loading rod (210) and a lower loading rod (220); the upper loading rod (210) is fixed to the high temperature environment box (100); and the lower loading rod (220) is connected to the load controller.

7. A creep performance testing system for overlapping low-melting-point brazing components according to claim 6, characterized in that: The displacement detection module comprises a first displacement extension rod, a second displacement extension rod and an extensometer (400), the first displacement extension rod is connected to the first clamping unit (300), the second displacement extension rod is connected to the second clamping unit (310), and the first displacement extension rod and the second displacement extension rod are connected to the extensometer (400).

8. The creep performance testing system of overlapping low-melting-point brazing components according to claim 7, characterized in that: The displacement detection module also includes a positioner, which includes a frame (401), a positioning member (402) and an adjusting bolt (403). The frame (401) is connected to the lower loading rod (220). The positioning block extends outward from both sides of the frame (401). The positioning block is provided with a positioning groove (404) parallel to the first extension rod (410) and the second extension rod (420). The first extension rod (410) and the second extension rod (420) pass through the positioning groove (404). The positioning block is provided with a positioning threaded hole parallel to the length direction of the positioning groove (404). The adjusting bolt (403) passes through the positioning threaded hole and abuts against the first extension rod (410) and the second extension rod (420).

9. A method for predicting creep life of overlapping low-melting-point brazing components, applied to the overlapping low-melting-point brazing component creep performance testing system according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, determining the material of the component to be evaluated, the component working temperature T, in °C and the working load P, in N, the brazing layer width a, in mm, the brazing layer length b, in mm, the brazing layer thickness s, in mm and the porosity A of the solder layer, in %; Step S2, placing the sample (500) into the high temperature environment box (100), respectively fixing and connecting the two ends of the sample (500) through the loading control module (200) and applying stress F, in units of N, clamping the edges of the weld (510) of the sample (500) on both sides through the sample (500) clamping module, and using the displacement detection module to detect the creep deformation δ, in units of mm; Step S3, by substituting the parameters of step S1 and the stress F and the creep deformation δ obtained in step S2 into the equation, the initial creep stress is calculated using the component shear stress τ in units of MPa and the creep strain is calculated using the component shear strain γ, which are dimensionless parameters; Step S4, forming a linear relationship between the brazing layer shear stress τ obtained in step 3 and the creep rupture time t(h), and a linear relationship between the brazing layer shear stress and the minimum creep shear strain rate ( / h) forming a linear relationship in a logarithmic coordinate system, determining whether the two relationship curves conform to a linear relationship in a double logarithmic coordinate system, and if both conform to a linear relationship, proceed to the next step S5; Step S5, for the overlapped brazing element subjected to shear deformation that satisfies the linear relationship in the double logarithmic coordinates in step 4, determine the service life of the overlapped brazing element subjected to shear deformation under the specified working load P, and the service life can be calculated by the formula.

10. A creep life prediction method for overlapping low-melting-point brazing components according to claim 9, characterized in that: The formula in step 3 is Wherein, F is the initial creep load during the creep test, in N, a is the width of the brazing layer, in mm, b is the length of the brazing layer, in mm, s is the thickness of the brazing layer, in mm, A is the porosity of the brazing layer, and is the shear creep deformation of the brazing layer during the creep test, in mm.

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