A creep performance testing system and life prediction method for overlapping low-melting-point brazing components

Abstract

The present invention is applicable to the field of welding testing and discloses a creep performance testing system and life prediction method for overlapped low-melting-point brazing components, comprising a high-temperature environmental chamber, a temperature control module for controlling the temperature in the high-temperature environmental chamber, a loading control module for applying a tensile load to a sample, a sample clamping module for clamping the edges of the weld seam of the sample, and a displacement detection module for detecting the creep degree of the sample; wherein the loading control modules are arranged at both ends of the high-temperature environmental chamber, the loading control modules are respectively connected to the sample clamping modules, and the sample clamping modules are respectively connected to the displacement detection modules.

Description

Technical Field

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

[0002] One of the key design principles of advanced third-generation pressurized water reactors (PWRs) is the use of passive measures to ensure safe operation of nuclear power units. Temperature-sensitive components based on lap soldering are widely used in the passive safety protection systems of my country's third-generation PWRs. Accurate characterization of material creep properties is a prerequisite for life analysis and environmental suitability assessment of soldered structures. Lap-brazed joints contain multiple complex regions, including the base metal, diffusion zone, and brazing filler metal. Each region of the brazed joint has distinct mechanical properties. The pinning effect of the brazed diffusion zone is the primary factor in maintaining the high-temperature strength of the soldered component. Conventional uniaxial testing cannot accurately characterize the high-temperature creep performance of lap-brazed joints. The test specimens consist of two metal plates welded together at a lap joint and brazed. Current creep testing equipment is typically clamped at both ends of the overlapping metal plates, which can easily cause metal deformation during tensile loading, leading to errors and inaccurate creep measurement. 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 this application to solve its technical problems is: a high-temperature environmental chamber, a temperature control module for controlling the temperature inside the high-temperature environmental chamber, a loading control module for applying a tensile load to the sample, a sample clamping module for clamping the edges of the weld on both sides 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 chamber, 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, a shaft 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 shaft 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 clamper, 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 a lap-jointed low-melting-point brazing component, comprising the following steps:

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

[0014] Step S2: placing the sample into the high-temperature environmental chamber, fixing the two ends of the sample and applying stress F (in N) via the loading control module, clamping the edges of the weld of the sample via the sample clamping module, and detecting the creep deformation δ (in mm) using the displacement detection module;

[0015] Step S3: Substitute the parameters from step S1 and the stress F and creep deformation δ obtained from step S2 into the equation to calculate the initial creep stress using the component shear stress τ in MPa and the creep strain using the component shear strain γ, which are dimensionless parameters.

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

[0017] 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 obtained through the formula.

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

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

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

[0021] The implementation of the present application's method for predicting the creep life of a lap-jointed 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 with a corresponding temperature and a corresponding tensile load. In addition, the detection data does not need to be screened for redundant data under the lap-jointed low-melting-point brazing component creep performance test system, and the creep deformation directly detected is true and reliable, which greatly simplifies the working life calculation process and improves the accuracy of the 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 with reference to the accompanying drawings and embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be considered as limiting the scope. A person of ordinary skill in the art can derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0023] Figure 1 This is an overall diagram of a creep performance testing system for overlapping low-melting-point brazing components 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 according to an embodiment of the present invention;

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

[0026] Figure 4 This is a three-dimensional diagram of a pattern fixing module of a lap-jointed low-melting-point brazing component creep performance testing system according to one embodiment of the present invention;

[0027] Figure 5 This is a cross-sectional view of a sample fixing module of a system for testing creep properties of overlapped low-melting-point brazing components in accordance with one embodiment of the present invention;

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

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

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

[0031] Figure 9This is a comparison diagram of creep test results at different initial stress levels in a method for predicting creep life of a lap-jointed low-melting-point brazing component according to one embodiment of the present invention;

[0032] Figure 10 This is a comparison chart of creep life prediction method for overlapped low-melting-point brazing components under the same initial stress level for a long time;

[0033] Figure 11 This is a comparison chart of creep short-time test results at different initial stress levels in a method for predicting creep life of a lap-jointed low-melting-point brazing component in one embodiment of the present invention.

[0034] Reference numerals

[0035] 100. High-temperature environmental chamber; 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 slot; 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 and are constructed and operated in specific directions. They are only for the convenience of describing the technical solution and do not indicate that the devices or components referred to must have specific directions. Therefore, they should not be understood as limiting the present invention.

[0037] It should also be noted that, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", "fixed", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and 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 intervening 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 the indicated technical features. Therefore, the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of such 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 creep performance testing system for overlap-type low-melting-point brazing components in one embodiment of the present invention is shown. The creep performance testing system for overlap-type low-melting-point brazing components can be used to perform creep performance tests on overlap-type brazed weldments. The system 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 sample 500 clamping module is used to clamp the edge of the weld 510 of the sample 500, rather than clamping it at both ends of the sample 500. This can greatly reduce the impact of the deformation of the metal at both ends of the sample 500 on the results of the sample 500. Then, by heating in a 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 amount of 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 in one embodiment, the first fixing seat and the second fixing seat may include the first fixing seat and the second fixing seat including a clamp 301, an axis 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 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 arranged 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 extensometer, a second displacement extensometer and an extensometer 400, wherein the first displacement extensometer is connected to the first clamping unit 300, the second displacement extensometer is connected to the second clamping unit 310, and the first displacement extensometer and the second displacement extensometer 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, meeting the accuracy requirements of creep testing.

[0049] Figure 1 and Figure 6 It is shown that the displacement detection module may include a positioner in one embodiment, and the positioner 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, which 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, which 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 misplacing, thereby improving the reliability of detection.

[0052] Figures 8 to 11 A method for predicting the 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 operating temperature T (unit: °C), the working load P (unit: N), the brazing layer width a (unit: mm), the brazing layer length b (unit: mm), the brazing layer thickness s (unit: mm), and the porosity A (unit: %) of the solder layer;

[0054] Step S2: Place the sample 500 into the high-temperature environmental chamber 100. Use the loading control module 200 to securely connect both ends of the sample 500 and apply a stress F (in N). Use the sample 500 clamping module to clamp both sides of the weld 510 of the sample 500. Use 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 creep deformation δ obtained in step S2 into the equation, the initial creep stress is calculated using the component shear stress τ in 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 and the creep rupture time t(h) obtained in step 3, and the brazing layer shear stress and the minimum creep shear strain rate Form a linear relationship in a logarithmic coordinate system, and determine whether the two relationship curves conform to a linear relationship in the double logarithmic coordinate system. If both conform to a linear relationship, proceed to the next step S5;

[0057] 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 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 service life of the sample under the working environment of the corresponding temperature and corresponding tensile load. In addition, the test data does not need to be screened with redundant data 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 service life calculation process and improves the accuracy of service life estimation.

[0059] The formula in step 3 is

[0060] Where 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 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 extrapolated and calculated by 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 obtained by fitting the creep test results of the lap-brazed component 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] Figure 11 The comparative test results of the test system proposed in this application and the conventional creep displacement test results in the standard are demonstrated. 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 specimens at both ends need to be fixed with corresponding holes. The specimens around the holes will be subjected to huge deformation, and the initial creep parameters need to be corrected. 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] Figure 9 It shows that under different tensile forces, conventional existing technologies will have an additional deformation at the beginning compared to the present application. This requires removal or addition of correction values ​​in conventional specimens, which greatly affects the test accuracy. As time goes on, creep is gradually destroyed, forming a fracture breakthrough, which is the final life of the brazing.

[0067] Figure 10 A comparison is shown under the same tensile force, 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 methods 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, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of 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 environmental box (100), a temperature control module for controlling the temperature in the high-temperature environmental 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 a weld (510) on both sides of the sample (500), and a displacement detection module for detecting the creep degree of the sample (500); The loading control modules (200) are arranged at both ends of the high-temperature environment box (100), the loading control modules (200) are respectively connected to the sample (500) clamping modules, and the sample (500) clamping modules are respectively connected to the displacement detection modules; The sample clamping module includes 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), wherein 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); The first fixing seat and the second fixing seat include a clamp (301), a shaft (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 shaft (302) hinges the clamping mechanism and the clamp (301); 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).

2. A creep performance testing system for overlapping low-melting-point brazing components according to claim 1, 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).

3. The creep performance testing system of a lap-jointed low-melting-point brazing element according to claim 1, characterized in that: The loading control module (200) includes a load controller, the loading control module (200) is arranged in the high-temperature environment box (100), and the load controller 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), 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.

4. A creep performance testing system for overlapping low-melting-point brazing components according to claim 3, characterized in that: The displacement detection module comprises a first extension rod (410), a second extension rod (420) and an extensometer (400), wherein the first extension rod (410) is connected to the first clamping unit (300), the second extension rod (420) is connected to the second clamping unit (310), and the first extension rod (410) and the second extension rod (420) are connected to the extensometer (400).

5. The creep performance testing system of overlapping low-melting-point brazing components according to claim 4, 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 blocks are extended outward from both sides of the frame (401). The positioning blocks are provided with positioning grooves (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 grooves (404). The positioning blocks are provided with positioning threaded holes parallel to the length direction of the positioning grooves (404). The adjusting bolts (403) pass through the positioning threaded holes and abut against the first extension rod (410) and the second extension rod (420).

6. A method for predicting creep life of a lap-jointed low-melting-point brazing component, using the lap-jointed low-melting-point brazing component creep performance testing system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: Determine the material and operating temperature of the component being evaluated T , in °C and working load P, in N, brazing layer width a, in mm, brazing layer length b, in mm, brazing layer thickness s, in mm and porosity A of the soldering layer, in %; Step S2, placing the sample (500) into the high temperature environment box (100), fixing and connecting the two ends of the sample (500) respectively by the loading control module (200) and applying stress F, in units of N, clamping the edges of the weld (510) of the sample (500) by the sample (500) clamping module, and detecting the creep deformation δ, in units of mm, by using a displacement detection module; Step S3, obtain stress through the parameters of step S1 and step S2 F Substituting the creep deformation δ into the equation, the initial creep stress is calculated using the component shear stress τ in 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 and the creep rupture time t (h) obtained in step 3, and the brazing layer shear stress and the minimum creep shear strain rate ( / h) forming a linear relationship in a logarithmic coordinate system, and determining whether the two relationship curves conform to a linear relationship in the double logarithmic coordinate system. 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. The service life can be calculated using the formula.

7. The creep life prediction method of a lap-jointed low-melting-point brazing component according to claim 6, characterized in that: The formula in step 3 is , ; Where F is the initial creep load during the creep test, unit N, a is the width of the brazing layer, unit mm, b is the length of the brazing layer, unit mm, s is the thickness of the brazing layer, unit mm, A is the porosity of the brazing layer, and δ is the shear creep deformation of the brazing layer during the creep test, unit mm.

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