Experimental device and method for evaluating anti-crack bridge failure capability of divergent die material for extrusion
By designing an experimental device comprising an upper and lower mold, combined with a high-temperature creep testing machine, the bending stress applied to the sample at high temperature is simulated, solving the problem of assessing the anti-crack bridge failure capability of split mold materials, realizing a low-cost and efficient evaluation method, and improving the accuracy and efficiency of the evaluation.
Patent Information
- Application Number
- CN202511364820.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2025-12-23
AI Technical Summary
Existing technologies make it difficult to efficiently and cost-effectively evaluate the anti-crack bridge failure capability of flow divider materials, especially under the actual service conditions of molds at high temperatures, resulting in long mold life assessment cycles and high costs.
Design an experimental setup including an upper mold and a lower mold, combined with a high-temperature creep testing machine, to simulate applying bending stress to the sample at high temperature and record the number of fatigue fractures of the sample under cyclic loading, in order to evaluate the anti-crack bridging failure capability of the shunt mold material.
It enables a simple and low-cost assessment of the anti-crack bridging failure capability of flow divider materials, and can accurately compare the performance of different materials or heat treatment processes, thus improving the evaluation efficiency and accuracy.
Smart Images
Figure CN121185804A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an experimental apparatus and method for evaluating the resistance of extrusion die materials to crack bridging failure, belonging to the field of material performance evaluation technology. Background Technology
[0002] In modern industrial sectors such as aerospace, rail transportation, and new energy vehicles, the demand for lightweight, high-strength hollow or complex cross-section metal profiles is surging. These profiles must meet the dual requirements of weight reduction and structural load-bearing capacity—for example, high-speed rail car frames require hollow aluminum profiles to reduce their weight (every 10% weight reduction can reduce energy consumption by 6%-8%), while aircraft engine nacelle components require complex cross-section titanium alloy profiles to achieve both lightweighting and high-temperature resistance. Die-extrusion is the primary means of achieving these product shapes.
[0003] As product performance requirements become increasingly stringent, so too do the demands on mold performance. The "bridge" of a sprue, as a core load-bearing component (simultaneously bearing metal thrust and core support), is particularly susceptible to cracking, which is one of the most common causes of mold failure. In actual production, the "bridge" primarily bears bending stress at high temperatures. Mold material and heat treatment processes are key factors affecting mold lifespan, and evaluating the material's resistance to cracking failure is crucial for improving product quality. Due to the long service life of molds, evaluating them by extruding actual products is not only time-consuming but also costly. Therefore, there is an urgent need to develop new evaluation devices and methods that can simulate the actual working conditions of sprue molds. Summary of the Invention
[0004] To evaluate the resistance of extrusion sprue materials to crack bridging failure, this invention provides an experimental apparatus and method for evaluating the resistance of extrusion sprue materials to crack bridging failure, which is low in cost, simple in design principle, and easy to manufacture.
[0005] The technical solution of this invention is as follows:
[0006] An experimental apparatus for evaluating the resistance of extrusion die materials to crack bridging failure, including an upper die and a lower die;
[0007] The upper mold is a frame structure with an opening. The upper frame is provided with an upper threaded rod, and the lower frame is provided with an opening. There are two opposing steps on both sides of the opening, and a sample stage is provided on the opposite surface of the two steps.
[0008] The lower mold has a frame structure, and the lower edge of the lower mold is provided with a threaded rod;
[0009] The lower mold is installed inside the opening of the upper mold, and the lower mold is perpendicular to the upper mold; the two steps correspond to the hollow part in the middle of the lower mold;
[0010] The upper edge of the lower die is a top beam, and the cross section of the top beam is wedge-shaped, with a wide upper top surface and a narrow lower bottom surface. The lower bottom surface of the top beam is provided with two first limiting ribs protruding downward, which are used to limit the sliding of the sample along the direction of the top beam.
[0011] The test sample is a cuboid structure, and the size in the length direction is greater than that in the width direction and the thickness direction. Two protruding second limiting ribs are arranged in the middle part of the upper surface in the length and width directions, which are also used to limit the sliding of the sample.
[0012] The sample table is a square groove arranged on the opposite surfaces of the two steps. The two ends of the sample in the length direction are respectively placed in the two square grooves. The size of the square groove matches the cross-sectional size of the sample, so that the sample can be horizontally arranged in the two square grooves of the sample table without shaking.
[0013] The first limiting rib has two first limiting ribs, and the height of the first limiting rib is higher than the thickness of the sample.
[0014] The second limiting rib has two second limiting ribs, and the width between the two second limiting ribs and the shape formed thereby are consistent with the thickness and shape of the lower part of the cross section of the top beam. In the stretching process, the first limiting rib and the second limiting rib are engaged with each other, so as to ensure that the sample does not slide relatively during the stretching process.
[0015] The experimental method for evaluating the crack bridge failure resistance of the material of the split die for extrusion is evaluated by the experimental device for evaluating the crack bridge failure resistance of the material of the split die for extrusion, which comprises the following steps:
[0016] When the experiment is carried out, first, the upper die is connected with the high-temperature rod stretching upper clamp of the high-temperature creep test machine, and then the lower die is connected with the high-temperature rod stretching lower clamp of the high-temperature creep test machine.
[0017] The upper die and the lower die are rotated to be vertical by rotating the upper threaded rod and the lower threaded rod.
[0018] Then, the lower die is raised to the inside of the upper die by operating the high-temperature creep test machine, and the top of the lower die is ensured to be obviously higher than the bottom of the upper die to place the step of the sample, so as to facilitate the placement of the test sample.
[0019] Then, the test sample is placed on the step at the bottom of the upper die, and the lower die is lowered to contact the sample by operating the high-temperature creep test machine. The position of the sample is fixed by the second limiting rib on the sample and the first limiting rib of the lower die.
[0020] Finally, the heating furnace of the high-temperature creep test machine is moved, and the matched upper die, lower die and sample are placed in the furnace and heated to the required temperature. The test sample is repeatedly subjected to bending stress by the cyclic loading module of the high-temperature creep test machine until the sample is fatigue fractured. The cycle number is recorded as the basis for evaluating the crack bridge failure resistance of the material of the split die for extrusion.
[0021] The anti-crack bridge failure ability of the flow distribution die material is evaluated according to the number of cycles of the sample under high-temperature creep, and specifically includes:
[0022] The anti-crack bridge failure ability of the flow distribution die material is evaluated according to the number of cycles of the sample under high-temperature creep, and specifically includes:
[0023] The beneficial effects of the present application are:
[0024] (1) The design principle is simple, and the manufacturing process is simple and easy to implement;
[0025] (2) It is practical, easy to operate, and has high evaluation efficiency;
[0026] (3) It can intuitively and accurately compare and evaluate the anti-crack bridge failure ability of different materials or the same material prepared by different heat treatment systems. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 is a schematic diagram of the overall structure of the present application;
[0028] Figure 2 is a schematic diagram of the upper die structure of the present application;
[0029] Figure 3 is a schematic diagram of the lower die structure of the present application;
[0030] Figure 4 is a schematic diagram of the test structure of the present application. DETAILED DESCRIPTION
[0031] The present application will be further described below in conjunction with the drawings and examples.
[0032] As shown in Figures 1 to 3 , the present embodiment provides an experimental device for evaluating the anti-crack bridge failure ability of a flow distribution die material for extrusion,
[0033] including an upper die 10 and a lower die 20;
[0034] The upper die 10 is a frame-shaped structure with an opening, the upper edge frame is provided with an upper threaded rod 1, the lower edge frame is provided with an opening, and the two sides of the opening are two opposite steps 2, and the opposite surfaces of the two steps 2 are provided with a sample table 3;
[0035] The lower die 20 is a frame-shaped structure, and the lower edge frame of the lower die 20 is provided with a lower threaded rod 4;
[0036] The lower die 20 is installed in the opening of the upper die 10, and the lower die 20 is perpendicular to the upper die 10; the two steps 2 correspond to the hollow part in the middle of the lower die 20;
[0037] The upper edge of the lower mold 20 is the top beam 6, which is wedge-shaped in cross section, with a wide upper surface and a narrow lower surface. The lower surface of the top beam 6 is provided with two downward protruding first limiting ribs 5, which are used to limit the sliding of the sample along the direction of the top beam 6.
[0038] As Figure 4 , the test sample is a rectangular structure, with the length direction being much larger than the width direction and the thickness direction. Two protruding second limiting ribs 7 are provided in the middle part of the upper surface in the length and width directions, which are also used to limit the sliding of the sample.
[0039] The sample platform 3 is a square groove provided on the opposite faces of the two steps 2. The two ends of the sample in the length direction are placed in the two square grooves respectively. The horizontal distance of the edge of the sample platform 3 is smaller than the length of the sample to be tested, and the distance of the inner edge is greater than the length of the sample to be tested. The size of the square groove matches the cross-sectional size of the sample, ensuring that the sample can be horizontally placed on the sample platform 3 without shaking.
[0040] The first limiting rib 5 has two, and the height of the first limiting rib 5 is higher than the thickness of the sample. The second limiting rib 7 has two, and the width between the two second limiting ribs 7 and the shape formed by the two second limiting ribs 7 are consistent with the thickness and shape of the lower part of the cross section of the top beam 6. During the stretching process, the first limiting rib 5 and the second limiting rib 7 are engaged with each other, thereby ensuring that the sample does not slide relatively during the stretching process.
[0041] Before the experiment starts, the relationship between the upper mold 10 and the lower mold 20 can be adjusted by adjusting the number of turns of the upper threaded rod 1 and the lower threaded rod 4, so that the upper mold 10 and the lower mold 20 are in a vertical relationship when assembled. The upper mold 10 is a hollow open frame structure, with an upper threaded rod 1 connected to a high-temperature creep test machine on the top, and the parameters such as tooth type, diameter, and pitch of the threaded rod match the high-temperature bar tensile clamp of the test machine. The bottom of the upper mold 10 is provided with two steps 2 extending inward on both sides, and a sample platform 3 for placing the sample is provided in the middle of the steps 2. The lower mold 20 is composed of a frame structure and a lower threaded rod 4 at the bottom, and the parameters such as tooth type, diameter, and pitch of the threaded rod match the high-temperature bar tensile clamp of the test machine. The frame structure of the lower mold 20 is provided with a first limiting rib 5 protruding downward on the top inner side, which is used to limit the sliding of the sample along the direction of the top beam 6. The cross section of the top beam 6 of the frame structure is wedge-shaped, with the outer edge being thicker than the other side, which can make the contact area between the top of the frame structure and the sample smaller, facilitating the bending test. The sample to be tested is a rectangular sample, with the length direction being much larger than the width direction and the thickness direction. Two protruding second limiting ribs 7 are provided in the middle part of the length-width surface, which are also used to limit the sliding of the sample.
[0042] In the embodiment, an experimental method for evaluating the crack bridge failure resistance of the material of the split die for extrusion is also provided, and the evaluation is performed by using the experimental device for evaluating the crack bridge failure resistance of the material of the split die for extrusion, and includes the following steps.
[0043] When the experiment is performed, first, the upper die 10 is connected with the upper clamp of the high-temperature bar tensile device of the high-temperature creep test machine, and then the lower die 20 is connected with the lower clamp of the high-temperature bar tensile device of the high-temperature creep test machine.
[0044] The upper die 10 and the lower die 20 are rotated to be vertical by rotating the upper threaded rod 1 and the lower threaded rod 4.
[0045] Then, the lower die 20 is raised to the inside of the upper die 10 by operating the high-temperature creep test machine, and the top of the lower die 20 is ensured to be obviously higher than the bottom of the upper die 10 to place the step 2 for placing the test sample, so as to facilitate the placement of the test sample.
[0046] Then, the test sample is placed on the step 2 at the bottom of the upper die 10, the lower die 20 is lowered to contact the sample by operating the high-temperature creep test machine, and the position of the sample is fixed by the second limiting rib 7 on the sample and the first limiting rib 5 of the lower die 20.
[0047] Finally, the heating furnace of the high-temperature creep test machine is moved, the matched upper die 10, lower die 20 and sample are placed in the furnace and heated to the required temperature, the sample is repeatedly subjected to bending stress by the cyclic loading module of the high-temperature creep test machine, until the sample is fatigue fractured. The cycle number is recorded as the basis for evaluating the crack bridge failure resistance of the material of the split die for extrusion.
[0048] The application is further described in combination with the following specific embodiments, but the application is not limited thereto.
[0049] Example 1
[0050] The upper die 10 and the lower die 20 are designed, wherein the upper threaded rod 1 on the top of the upper die 10 connected with the upper threaded rod 1 of the high temperature creep test machine is of the British fine thread, the diameter is 20 mm, and the pitch is 1.6 mm; the bottom is provided with a step 2 extending inwardly by 30 mm, and the middle of the step 2 is provided with a sample table 3 for placing the sample, which is a cuboid with the size of 10*10*15 mm. The lower threaded rod 4 on the bottom of the lower die 20 is consistent with the upper threaded rod 1 on the top of the upper die 10 in terms of the thread type, diameter, pitch and other parameters, and is matched with the high temperature bar tensile clamp of the test machine; the first limiting rib 5 on the inner side of the top of the frame-shaped structure protrudes downwardly with the height of 12 mm and the thickness of 2 mm, and is used for limiting the sliding of the sample along the top beam; the top beam 6 of the frame-shaped structure is wedge-shaped in cross section, and the part close to the outer edge of the frame is thicker than the other side, so that the contact area of the top of the frame-shaped structure with the sample is smaller, and the bending test is facilitated. The sample H13 steel to be tested is a cuboid with the size of 10*10*100 mm, and two protruding second limiting ribs 7 are arranged on the middle part of the length-width surface with the height of 5 mm and the average thickness of 2 mm, and are used for limiting the sliding of the sample in the direction perpendicular to the top beam 6. During the experiment, the upper die 10 is connected with the upper clamp of the high temperature bar tensile clamp of the high temperature creep test machine, and then the lower die 20 is connected with the lower clamp of the high temperature bar tensile clamp of the high temperature creep test machine; the upper die 10 and the lower die 20 are rotated to be perpendicular by rotating the upper threaded rod 1 and the lower threaded rod 4, and then the lower die 20 is lifted to the inside of the upper die 10 by operating the high temperature creep test machine, and it is ensured that the top of the lower die 20 is obviously higher than the step 2 for placing the sample on the bottom of the upper die 10; then, the H13 steel sample to be tested is placed on the sample table 3 on the bottom of the upper die 10, the lower die 20 is lowered to contact the H13 steel sample by operating the high temperature creep test machine, and the position of the sample is fixed by the second limiting rib 7 on the H13 steel sample and the first limiting rib 5 of the lower die 20; finally, the heating furnace of the high temperature creep test machine is moved, the matched upper die 10, lower die 20 and sample are placed in the furnace and heated to 480℃, and the sample is repeatedly subjected to the bending stress of 800 MPa by the cyclic loading module of the high temperature creep test machine until the sample is fatigued and fractured. The cycle number is recorded, and the more the cycle number is, the stronger the anti-bridge failure ability of the material is. The specific experimental data is shown in Table 1.
[0051] Table 1 Anti-bridge failure ability statistics of H13 steel material of extrusion split die
[0052]
[0053] As shown in Table 1, the split die H13 steel material prepared by the heat treatment process of quenching at 1060°C and tempering at 560°C for 8h has the relatively optimal anti-bridge failure capacity under the cyclic loading at 480°C, 2mm / min and 800MPa, and the cycle number is 1025; the split die H13 steel material prepared by the heat treatment process of quenching at 1060°C and tempering at 520°C for 8h has the relatively poor anti-bridge failure capacity under the same cyclic loading condition, and the change trend is process 2>process 3>process 1. The split dies of a product are heat treated by the above-mentioned three heat treatment processes, and the number of extruded aluminum alloy rods is 83, 125 and 103 respectively. Therefore, the service life of the die produced by process 2 is the longest, the service life of the die produced by process 3 is the second longest, and the service life of the die produced by process 1 is the shortest, and the change trend is consistent with the result of the evaluation by the method.
[0054] Example 2
[0055] In Example 2, the bridge failure materials of the split die for extrusion are 3Cr2W8V, H13 and H10 respectively, and the rest is the same as Example 1. The specific experimental data is shown in Table 2.
[0056] Table 2 Anti-bridge failure capacity statistics of 3Cr2W8V, H13 and H10 steel materials of split die for extrusion
[0057]
[0058] As shown in Table 2, the 3Cr2W8V material of the split die for extrusion prepared by the heat treatment process of quenching at 1060°C and tempering at 560°C for 8h has the relatively poor anti-bridge failure capacity under the cyclic loading at 480°C, 2mm / min and 800MPa, and the cycle number is 897; the H10 steel material of the split die for extrusion prepared by the same heat treatment process has the relatively excellent anti-bridge failure capacity under the cyclic loading at 480°C, 2mm / min and 800MPa, and the cycle number is 1254 when fatigue fracture occurs, and the change trend is process 3>process 2>process 1. The split dies of a product for extrusion are prepared by the above-mentioned three materials, and the number of produced rods is 103, 125 and 151 respectively. Therefore, the service life of the die produced by process 3 is the longest, the service life of the die produced by process 2 is the second longest, and the service life of the die produced by process 1 is the shortest, and the change trend is consistent with the result of the evaluation by the method.
Claims
1. An experimental apparatus for evaluating the resistance to crack bridging failure of extrusion die materials, characterized in that, It includes an upper mold (10) and a lower mold (20); The upper mold (10) is a frame structure with an opening. The upper frame is provided with an upper threaded rod (1), and the lower frame is provided with an opening. There are two opposing steps (2) on both sides of the opening, and a sample stage (3) is provided on the opposite surface of the two steps (2). The lower mold (20) is a frame structure, and the lower frame of the lower mold (20) is provided with a threaded rod (4); The lower mold (20) is installed inside the opening of the upper mold (10), and the lower mold (20) is perpendicular to the upper mold (10); the two steps (2) correspond to the hollow part in the middle of the lower mold (20); The upper frame of the lower mold (20) is a top crossbeam (6), the cross section of the top crossbeam (6) is wedge-shaped, the upper top surface is wide and the lower bottom surface is narrow; the lower bottom surface of the top crossbeam (6) is provided with two downward protruding first limiting ribs (5), the first limiting ribs (5) are used to restrict the sample from sliding along the direction of the top crossbeam (6); The test sample is a cuboid structure with a length dimension greater than the width and thickness dimensions. Two protruding second limiting ribs (7) are provided in the middle part of the upper surface where the length and width are located, which are also used to limit the sliding of the sample. The sample stage (3) is a square groove on the opposite surface of the two steps (2). The two ends of the sample to be tested along the length direction are placed in the two square grooves respectively. The size of the square groove matches the cross-sectional size of the sample, ensuring that the sample can be placed horizontally in the two square grooves of the sample stage (3) without shaking.
2. The experimental apparatus for evaluating the anti-crack bridging failure capability of extrusion sprue materials according to claim 1, characterized in that, There are two first limiting ribs (5), and the height of the first limiting ribs (5) is higher than the thickness of the sample.
3. The experimental apparatus for evaluating the anti-crack bridging failure capability of extrusion sprue materials according to claim 1, characterized in that, There are two second limiting ribs (7), and the width between the two second limiting ribs (7) and the shape they form are consistent with the thickness and shape of the lower part of the cross section of the top beam (6).
4. An experimental method for evaluating the resistance to crack bridging failure of extrusion die materials, characterized in that, The method using the experimental apparatus for evaluating the anti-crack bridging failure capability of extrusion sprue materials according to any one of claims 1 to 3 includes the following steps: When conducting the experiment, first connect the upper mold (10) to the upper clamp of the high temperature bar tension tester of the high temperature creep tester, and then connect the lower mold (20) to the lower clamp of the high temperature bar tension tester of the high temperature creep tester. The upper die (10) and lower die (20) are rotated to a vertical position by rotating the upper threaded rod (1) and the lower threaded rod (4); Then, by running a high-temperature creep tester, the lower mold (20) is raised into the upper mold (10), and the top of the lower mold (20) is significantly higher than the step (2) at the bottom of the upper mold (10) where the test sample is placed, so as to facilitate the placement of the test sample. Then, the test specimen is placed on the step (2) at the bottom of the upper mold (10), and the lower mold (20) is moved down to contact the specimen by running the high temperature creep tester. The position of the specimen is fixed by the second limiting rib (7) on the specimen and the first limiting rib (5) of the lower mold (20). Finally, the heating furnace configured in the high-temperature creep tester is moved, and the fitted upper mold (10), lower mold (20) and sample are placed in the furnace and heated to the required temperature. The cyclic loading module of the high-temperature creep tester is used to repeatedly apply bending stress to the sample until the sample undergoes fatigue fracture. The number of cycles is recorded as the basis for evaluating the anti-crack bridge failure capability of the extrusion sprue material.