A pull-off force test device

Abstract

The present invention relates to a pull-off force test device, which is used to cooperate with a stretching machine to perform a pull-off force test on a sample formed by expanding a plurality of test tubes on a test block, and comprises: a first fixing device, the top end of which is detachably connected and fixed to the pull head of the stretching machine, and the bottom end of which is detachably connected and fixed to the test tube to be tested, and is used to connect and fix the tube to be tested of the sample to the pull head of the stretching machine; a second fixing device, the bottom of which is fixed to the base or the ground of the stretching machine, and the top of which is detachably connected and fixed to the test block of the sample, and is used to fix the sample directly under the pull head of the stretching machine. The present invention can effectively avoid deformation of the tube, simplify the operation steps, and save test block and test tube resources, reduce work intensity and operation difficulty, improve test accuracy and test efficiency, reduce test costs, and has good practicality and economic value.

Description

Technical Field

[0001] The invention relates to a pull-off force testing device, in particular to a pull-off force testing device used for testing and verifying hydraulic expansion parameters of pipes in nuclear power equipment, belonging to the technical field of tooling. Background Art

[0002] The steam generator is a key device in the primary circuit of a nuclear power plant. Its function is to transfer the heat of the heat carrier in the reactor to the secondary circuit, so that the secondary circuit produces steam of a certain pressure to drive the turbine. In the manufacturing process of the steam generator, the tube bundle (including 8,000 to 10,000 tubes) where the heat carrier is placed is expanded with the tube sheet by mechanical hydraulic method. The heat carrier in the steam generator is radioactive. After the tube bundle and the tube sheet are expanded, they not only play the role of blocking radioactivity, but also have the function of conducting heat. Therefore, the quality requirements of the expansion process are very high. If a leakage accident occurs, it will seriously affect the stability and safety of the steam generator. Therefore, before the expansion process, it is necessary to conduct tests to select appropriate expansion parameters such as hydraulic expansion force. The current practice is to use a tensile machine to perform a pull-off force test to verify the expansion parameters.

[0003] The steps of the pull-off force test are: 1. Expand one end of multiple processed test tubes (usually made of stainless steel) on a test block with different expansion parameters to form a test sample; 2. Fix the test block, fix the pull head of the tensile machine to the end of one of the tubes to be tested, and stretch the tensile machine upward with the tensile force standard required by the process to verify whether the expansion parameters are qualified; 3. Release the pull head and the test tube, adjust the position of the test block so that the next tube to be tested is in the test position, and repeat step 2 for testing until all test tubes on the test block are tested. In the daily test process, we found that due to the design defects of traditional test equipment, the test efficiency, accuracy, convenience, cost and other aspects have been affected, specifically:

[0004] First, the traditional test device uses a wedge-shaped hydraulic clamp to directly clamp the end of the test tube to fix it. However, due to the large holding force of the wedge-shaped hydraulic clamp, the test tube is often severely squeezed and deformed during the test, which wastes test tube resources and increases the test cost.

[0005] Second, the wedge-shaped hydraulic clamp will exert a reverse force on the test tube when clamping it, which will have a certain impact on the accuracy of the experiment;

[0006] Third, since the clamp on the stretching machine is large in size, space must be reserved for the clamp between the test tubes, so that the test block cannot fill the test tube, the test tubes are sparsely arranged, and the test block resources cannot be effectively utilized, resulting in a waste of test block resources; and, since the material strength requirements of the test block are high, the cost of the test block is high, which further increases the cost of the test;

[0007] Fourth, in order to avoid wasting test block resources, a special high-low intubation method is usually adopted, but this method is difficult to intubate, inefficient, and consumes a lot of test tubes;

[0008] Fifth, during the test, the stretching machine needs to be aligned and fixed with the tube to be tested. Since the horizontal position of the stretching head is fixed and cannot be moved, the test block needs to be readjusted and fixed each time the tube to be tested is changed. The test blocks are usually large in size. Due to the design of traditional test block fixing components, the test blocks need to be moved over a large range during the test, and the operation of fixing the test blocks is cumbersome. Therefore, it is difficult to center, adjust the position of the test blocks and fix the test blocks, resulting in low test efficiency, high operation difficulty and work intensity. Summary of the invention

[0009] The purpose of the present invention is to provide a pull-off force testing device, which can effectively avoid tube deformation while performing a pull-off force test, simplify the operating steps, save test block and test tube resources, reduce work intensity and operating difficulty, improve test accuracy and test efficiency, reduce test costs, and has good practicality and economic value.

[0010] To achieve the above object, the present invention provides a pull-off force test device, which is used to cooperate with a tensile machine to perform a pull-off force test on a sample formed by expanding a plurality of test tubes on a test block, comprising:

[0011] A first fixing device, the top end of which is detachably connected and fixed to the pull head of the stretching machine, and the bottom end of which is detachably connected and fixed to the test tube to be tested, and is used to connect and fix the test tube to be tested to the pull head;

[0012] The second fixing device has a bottom fixed on the base of the tensile machine or the ground, and a top that supports and fixes the sample.

[0013] Further, the first fixing device comprises:

[0014] A slider fixing assembly, the top end of which is detachably connected and fixed to the slider, and the bottom end of which is provided with a first connecting portion;

[0015] The test tube fixing assembly has a second connecting portion at the top, and the second connecting portion can be detachably connected and fixed to the first connecting portion; the bottom end of the test tube fixing assembly is connected and fixed to the upper end of the test tube to be tested.

[0016] Further, the second fixing device comprises:

[0017] A base, the bottom of which is fixed to the base of the tensile machine or the ground, and is used to fix the second fixing device so that no displacement or shaking occurs during the test;

[0018] A support platform, the top surface of which is a horizontal surface, used to carry the sample, and the bottom surface of which is connected and fixed to the base;

[0019] The test block fixing assembly is used to fix the test block on the top surface of the supporting platform.

[0020] Preferably, the test tube fixing component is made of a weldable material, and the test tube fixing component is fixed to the upper end of the test tube by welding.

[0021] Preferably, the first connecting portion and the second connecting portion are a pair of mutually matching threaded structures, which can be locked or disengaged by relative rotation.

[0022] Preferably, the first connection portion can rotate freely relative to the slider fixing assembly body, so as to ensure that the slider fixing assembly body does not move with the first connection portion when the first connection portion is rotationally connected to the second connection portion.

[0023] Further, the test block fixing assembly comprises:

[0024] A pressing plate, used for cooperating with the supporting platform to clamp the test block in a vertical direction;

[0025] A first positioning hole vertically extending between the upper and lower surfaces of the pressing plate;

[0026] A second positioning hole, which is vertically connected between the upper and lower surfaces of the support platform and has a hole diameter consistent with that of the first positioning hole;

[0027] A positioning locking component, which can cooperate with the first positioning hole and the second positioning hole to clamp and fix the test block between the pressing plate and the supporting platform;

[0028] The test block fixing components are at least two groups, which are arranged in different directions around the periphery of the test block.

[0029] Preferably, there are multiple second positioning holes to accommodate test blocks of different sizes and specifications and to fine-tune the position of the test block.

[0030] Preferably, the test block fixing assembly also includes a height adjustment device placed between the pressure plate and the support platform, which is used to support the plate body of the pressure plate at one end away from the test block, and adjust the support height so that the bottom surface of the pressure plate is in close contact with the top surface of the test block without an angle.

[0031] Preferably, the base is also provided with a horizontal position adjustment device for adjusting the horizontal position of the second fixing device.

[0032] In summary, compared with the prior art, the pull-off force test device provided by the present invention has the following beneficial effects:

[0033] 1. Improve the test accuracy. Use threaded or other connection methods instead of wedge-shaped hydraulic clamps to fix the test tube, eliminating the influence of reverse force and improving the accuracy of test data;

[0034] 2. Improve test efficiency. By improving the connection and fixing form between the test tube and the pull head, as well as the design of the test block fixing device, the operation steps are simplified and the work efficiency is improved. After actual verification, the original test of only 2 to 3 test tubes can be completed per working hour, but now 7 to 8 can be completed per working hour, and the test cycle is shortened to one third of the original;

[0035] 3. Reduce test costs. By improving the connection and fixing form between the test tube and the pull head, the technical problem of test tube deformation under pressure is solved. The test tube can be reused, and the reserved operation space of the test tube is reduced, the utilization rate of the test block is improved, and the consumption of the test tube is reduced; in addition, by improving efficiency, a lot of labor costs and time costs are saved;

[0036] 4. Reduce the difficulty of operation and work intensity. By improving the connection and fixing form between the test tube and the pull head, the need for a special high-low insertion method is avoided, the operation steps are simplified, and the difficulty of operation is reduced; in addition, by improving the test block fixing device, the position of the test block can be adjusted only in a small range, reducing the work intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the pull-off force testing device of the present invention;

[0038] Figure 2 It is a top view schematic diagram of the support assembly and the test block of the present invention;

[0039] Figure 3 It is a schematic top view of a sample of the present invention. DETAILED DESCRIPTION

[0040] The following is a further detailed description of a pull-off force test device proposed in the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0041] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0042] In the manufacturing process of nuclear power equipment steam generator, it is necessary to hydraulically expand the tube bundle and tube sheet with appropriate expansion parameters. Therefore, before the expansion process, a pull-off force test must be performed using a tensile machine 1 to verify the expansion parameters. Before the test, one end of a plurality of processed test tubes 21 (generally made of stainless steel) is expanded on a square test block 22 with different expansion parameters to form a test sample 2 as the test object, such as Figure 3 shown.

[0043] Combined with Figures 1 to 3 As shown, a pull-off force test device provided in this embodiment is used to cooperate with a stretching machine 1 to perform a pull-off force test on a sample 2. All components are made of metal, preferably stainless steel, and include:

[0044] A first fixing device 3 is disposed between the pull head 11 of the stretching machine 1 and the tube 21 to be tested of the sample 2, and is used to connect and fix the pull head 11 to the upper end of the tube 21 to be tested;

[0045] The second fixing device 4 is disposed on the base or the ground of the stretching machine 1 and is used to fix the sample 2 directly below the pull head 11 of the stretching machine 1 .

[0046] In this embodiment, the first fixing device 3 includes: a pull head fixing component 31 and a plurality of test tube fixing components 32;

[0047] The top end of the slider fixing assembly 31 is detachably connected and fixed to the slider 11, and can be fixed by means of threads, buckles, positioning pins or clamps. In this embodiment, threads are used for fixing. The bottom end of the slider fixing assembly 31 is provided with a first connecting portion. In this embodiment, a threaded sleeve with a hollow inner wall and threads is used.

[0048] A second connection portion is provided at the top of each test tube fixing assembly 32. In this embodiment, an outwardly protruding threaded plug is used. The size and thread of the threaded plug are adapted to the size and thread of the threaded sleeve of the pull head fixing assembly 31. The pull head fixing assembly 31 and the test tube fixing assembly 32 can be connected and fixed by relative rotation. The bottom end of each test tube fixing assembly 32 is consistent with the inner diameter of the test tube 21. Before the test, the bottom end of each test tube fixing assembly 32 is welded and fixed to the top of each corresponding test tube 21 by a fillet weld (welding along the intersection of two intersecting or nearly intersecting weldments).

[0049] Preferably, the first connecting portion and the main body of the pull head fixing assembly 31 are not an integral structure, and the first connecting portion can rotate freely relative to the main body of the pull head fixing assembly 31, so that when the first connecting portion is rotationally connected with the second connecting portion, the main body of the pull head fixing assembly does not move with it, thereby realizing that only the first connecting portion needs to be rotated alone to connect or separate the main body of the pull head fixing assembly 31 and the test tube fixing assembly 32, thereby making the operation of switching the test tube 21 faster and more convenient.

[0050] In this embodiment, the second fixing device 4 includes: a base 41, a support platform 42, and a test block fixing assembly 43;

[0051] Wherein, the base 41 includes a sleeve, a core and a positioning mechanism;

[0052] Furthermore, the sleeve is a hollow cylindrical sleeve with openings at the upper and lower ends, and the wall thickness needs to meet the load-bearing requirements of the test, and the top of the sleeve is fixed to the bottom surface of the support platform 42;

[0053] The core body can be a solid cylinder, or a hollow cylinder with a wall thickness that meets the load-bearing requirements; the bottom of the core body is fixed on the ground directly below the slider 11, and when the base of the stretching machine 1 is provided on the ground directly below the slider 11, the bottom of the core body is fixed on the base of the stretching machine 1; the outer diameter of the core body is matched with the inner diameter of the sleeve, and the core body can be exactly inserted into the sleeve;

[0054] The positioning mechanism includes: a through sleeve positioning hole arranged on the side wall of the sleeve, a through core positioning hole arranged on the side of the core, and a positioning pin. The sizes and positions of the sleeve positioning hole and the core positioning hole, as well as the size of the positioning pin are matched, so that the positioning pin can pass through the sleeve positioning hole and the core positioning hole to lock the base 41, and no displacement or shaking occurs during the test.

[0055] Furthermore, the support platform 42 is a rectangular parallelepiped with a square top surface, used to carry the sample 2, the top surface area of ​​the support platform 42 is larger than the bottom surface area of ​​the test block 22, and the bottom surface of the support platform 42 is welded and fixed to the top of the base 41;

[0056] Further, the test block fixing assembly 43 is used to fix the test block 22 on the top surface of the support platform 42, and includes: a pressing plate 431, a first positioning hole 433, a second positioning hole 434 and a positioning locking component 432;

[0057] The pressing plate 431 is a plate-shaped body with certain compression and bending strength, and cooperates with the supporting platform 42 to clamp the test block 22 in the vertical direction;

[0058] The first positioning hole 433 is a vertical through hole provided between the upper and lower surfaces of the pressing plate 431;

[0059] The second positioning hole 434 is a vertical through hole provided between the upper and lower surfaces of the support platform 42, and the hole diameter is consistent with the hole diameter of the first positioning hole 433;

[0060] The positioning and locking component 432 can adopt a fixing structure such as thread, riveting, and positioning pins. The present embodiment adopts a pair of matching positioning bolts and nuts, and the positioning bolts are passed through the first positioning hole 433 and the second positioning hole 434 in sequence and then locked and fixed with nuts; wherein, the bolt diameter of the positioning bolt and the hole diameter of the first positioning hole 433 and the second positioning hole 434 can be matched and assembled, so that the bolt body of the positioning and locking component 432 can pass through the first positioning hole 433 and the second positioning hole 434, while the bolt cap and the nut of the positioning and locking component 432 cannot pass through the first positioning hole 433 and the second positioning hole 434.

[0061] Preferably, the test block fixing assembly 43 also includes a height adjustment device 435. This embodiment uses a jack, which is placed between the pressure plate 431 and the support platform 42 to support the plate body of the pressure plate 431 at one end away from the test block 22, and adjust the support height so that the bottom surface of the pressure plate 431 is in close contact with the top surface of the test block 22 without an angle.

[0062] Preferably, the test block fixing components 43 should be at least 2 groups, preferably 4 groups, which are arranged in different directions around the test block 22, and preferably evenly arranged in relative directions.

[0063] After installation, the pressing plate 431 is horizontal, with one end of the bottom surface affixed to the top surface of the test block 22 and the other end affixed to the upper surface of the height adjustment device 435. The positioning bolt of the positioning locking component 432 passes through the first positioning hole 433 and the second positioning hole 434, and is locked with the nut to clamp the test block 22 between the pressing plate 431 and the supporting platform 42.

[0064] Preferably, Figure 2 As shown, a plurality of the second positioning holes 434 are provided on the support platform 42, and are evenly spaced from the center to the periphery of the support platform 42, with a spacing distance of preferably 1 cm, so as to be applicable to test blocks 22 of various specifications, and the method of fixing the test block 22 is more flexible and diverse, and the position of the micro-adjustment block 22 and the centering operation of the test tube 21 are made easier.

[0065] Preferably, the base 41 is also provided with a horizontal position adjustment device, which can adjust the horizontal position relative to the base or support platform 42 of the stretching machine 1, so as to achieve fine adjustment of the position of the test block 22 without disassembling and reassembling the test block fixing assembly 43, and can further facilitate the switching of the test tube 21 and the centering operation.

[0066] The test process of the pull-off force test using the pull-off force test device provided in this embodiment is as follows:

[0067] 1. Welding the test tube fixing assembly 32. Align the top end of the test tube 21 with the bottom end of the test tube fixing assembly 32, and weld them in the form of a fillet weld. Repeat the operation steps to complete the welding of all the test tubes 21 on the sample 2.

[0068] 2. Install the second fixing device 4. Sleeve the sleeve of the base 41 onto the core body fixed on the base of the stretching machine 1, rotate the sleeve so that the sleeve positioning hole coincides with the core body positioning hole, and insert the positioning pin to lock it.

[0069] 3. Install the slider fixing assembly 31. The threads of the slider fixing assembly 31 are butted against the threads of the slider 11 and locked, so that the slider fixing assembly 31 and the slider 11 are firmly connected.

[0070] 4. Fix the sample 2. Place the sample 2 on the support platform 42, adjust the appropriate position, and make the test tube fixing assembly 32 on a certain tube 21 to be tested completely vertically aligned with the pull head fixing assembly 31; adjust the height of the height adjustment device 435 between the pressing plate 431 and the support platform 42, so that the height of the height adjustment device 435 and the test block 22 are consistent, and the pressing plate 431 is placed on the top surface of the test block 22 and the height adjustment device 435; pass the positioning bolt of the positioning and locking component 432 from bottom to top through the second positioning hole 434 at the corresponding position on the support platform 42 and the first positioning hole 433 on the pressing plate 431, and then lock the nut of the positioning and locking component 432 to clamp and fix the test block 22 between the pressing plate 431 and the support platform 42; according to the same operating steps, install at least two sets of test block fixing assemblies 43 in different directions of the test block 22 to prevent the test block 22 from loosening and shaking.

[0071] 5. Connect the test tube fixing assembly 32 to the pull head fixing assembly 31. Align the threaded sleeve of the test tube fixing assembly 32 with the threaded plug of the pull head fixing assembly 31 vertically, lower the height of the pull head 11, rotate the threaded sleeve to lock it, and connect and fix the pull head 11 to the test tube 21 through the pull head fixing assembly 31 and the test tube fixing assembly 32.

[0072] 6. Start the test. The tensile machine 1 applies force to stretch upward, and the applied tension is transmitted to the test tube 21 through the pull head 11 and the first fixing device 3. When the tension reaches the value specified by the process requirements (generally 15 to 20 kN), the pull-off force test of the current test tube 21 is completed. If there is no gap or deformation or looseness between the test tube 21 and the test block 22, the verification result shows that the expansion parameters meet the technical requirements. Repeat steps 4 to 6 and perform pull-off force tests on all test tubes 21 of sample 2 in turn.

[0073] In summary, compared with the prior art, the pull-off force test device provided by the present invention eliminates the influence of the reverse force and improves the accuracy of the test data by adopting other connection methods instead of the wedge-shaped hydraulic clamp to fix the test tube; at the same time, it solves the technical problem of the compressive deformation of the test tube, and the test tube can be reused, reducing the waste of the test tube; by improving the connection form between the test tube and the pull head, the reserved operation space of the test tube is reduced, and the utilization rate of the test block is improved; by improving the design of the test block fixing device, the operation steps are simplified and the work efficiency is improved.

[0074] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A pull-off force test device, used in conjunction with a tensile machine to perform a pull-off force test on a sample formed by expanding a plurality of test tubes on a test block, characterized in that: include: A first fixing device, the top end of which is detachably connected and fixed to the pull head of the stretching machine, and the bottom end of which is detachably connected and fixed to the test tube to be tested, and is used to connect and fix the test tube to be tested to the pull head; A second fixing device, the bottom of which is fixed on the base of the tensile machine or the ground, and the top of which carries and fixes the sample; A slider fixing assembly, the top end of which is detachably connected and fixed to the slider, and the bottom end of which is provided with a first connecting portion; A test tube fixing assembly, the top of which is provided with a second connecting portion, the second connecting portion and the first connecting portion can be detachably connected and fixed; the bottom end of the test tube fixing assembly is connected and fixed to the upper end of the test tube to be tested; A base, the bottom of which is fixed to the base of the tensile machine or the ground, and is used to fix the second fixing device so that no displacement or shaking occurs during the test; A support platform, the top surface of which is a horizontal surface, used to carry the sample, and the bottom surface of which is connected and fixed to the base; The test block fixing assembly is used to fix the test block on the top surface of the supporting platform.

2. The pull-off force testing device according to claim 1, characterized in that: The test tube fixing component is made of a weldable material, and the test tube fixing component is fixed to the upper end of the test tube by welding.

3. The pull-off force testing device according to claim 1, characterized in that: The first connection part and the second connection part are a pair of mutually matching thread structures, which can be locked or released by relative rotation.

4. The pull-off force testing device according to claim 3, characterized in that: The first connection portion can rotate freely relative to the slider fixing assembly body, so as to ensure that the slider fixing assembly body does not move with the first connection portion when the first connection portion is rotationally connected to the second connection portion.

5. The pull-off force testing device according to claim 1, characterized in that: The test block fixing assembly comprises: A pressing plate, used for cooperating with the supporting platform to clamp the test block in a vertical direction; A first positioning hole vertically penetrates between the upper and lower surfaces of the pressing plate; A second positioning hole, which is vertically connected between the upper and lower surfaces of the support platform and has a hole diameter consistent with that of the first positioning hole; A positioning locking component, which can cooperate with the first positioning hole and the second positioning hole to clamp and fix the test block between the pressing plate and the supporting platform; The test block fixing components are at least two groups, which are arranged in different directions around the periphery of the test block.

6. The pull-off force testing device according to claim 5, characterized in that: There are multiple second positioning holes, which are used to accommodate test blocks of different sizes and specifications and to fine-tune the position of the test block.

7. The pull-off force testing device according to claim 5, characterized in that: The test block fixing assembly also includes a height adjustment device placed between the pressure plate and the support platform, which is used to support the plate body of the pressure plate at one end away from the test block and adjust the support height so that the bottom surface of the pressure plate is in close contact with the top surface of the test block without an angle.

8. The pull-off force testing device according to claim 1, characterized in that: The base is also provided with a horizontal position adjusting device for adjusting the horizontal position of the second fixing device.

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