Reaming experiment equipment
By designing a hole-expansion test fixture for sheet metal on a tensile testing machine, and using a force sensor to automatically determine the cracking at the edge of the hole, the problems of high cost and insufficient accuracy in hole-expansion testing are solved, achieving efficient and low-cost hole-expansion testing and production optimization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NIO TECH ANHUI CO LTD
- Filing Date
- 2025-01-10
- Publication Date
- 2026-04-28
AI Technical Summary
Existing hole expansion testing equipment is expensive, and tensile testing machines cannot perform hole expansion tests, leading to increased costs and insufficient testing accuracy for enterprises.
Design a plate hole expansion test fixture, including a concave die, a convex die and a fixing structure, which can perform hole expansion tests on a tensile testing machine and automatically determine the cracking of the hole edge of the plate using a force sensor, thus replacing the cupping test machine.
It reduces the cost of hole expansion experiments, improves detection accuracy, eliminates errors caused by human operation, and achieves efficient quantitative identification of edge cracking risks in sheet metal and optimization of production processes.
Smart Images
Figure CN224168496U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of experimental equipment technology, and in particular relates to a hole expansion experimental device. Background Technology
[0002] In the field of sheet metal edge cracking failure research, the hole expansion test is a thin sheet formability test. A punch presses a specimen with a central hole into a die, enlarging the central hole until necking or cracks appear at the edge of the hole. This test can effectively evaluate the flanging formability of thin metal sheets. By clarifying the main influencing factors of sheet metal edge formability through hole expansion tests, exploring the relationship between hole expansion rate and edge cracking of stamped body panels, and obtaining quantitative indicators of sheet metal edge cracking, it is possible to effectively quantify and identify the risk of edge cracking in metal sheets, and modify and optimize production processes.
[0003] However, the current mainstream hole expansion test is mainly completed by special machinery such as cupping test machine, which is expensive and increases the cost of enterprises; and existing tensile testing machines cannot perform hole expansion test. Utility Model Content
[0004] The purpose of this application is to provide a hole enlargement test device to solve the problem of high cost of traditional hole enlargement tests.
[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:
[0006] The first aspect of this application provides a plate hole expansion test fixture for use on a tensile testing machine, comprising:
[0007] The die includes a die body and a die connecting part disposed on the die body, the die connecting part being used to connect to the first working platform of the tensile testing machine;
[0008] The punch includes a punch body and a punch connecting part disposed on the punch body, the punch connecting part being used to connect to the second working platform of the tensile testing machine;
[0009] A fixed structure, detachably mounted on the concave mold, is used to fix the experimental plate onto the concave mold body.
[0010] In some implementations, one end of the punch body is a conical tip, and the punch connecting portion is located at the end of the punch body away from the conical tip.
[0011] In some implementations, the punch connection is threadedly connected to the second working platform.
[0012] In some implementations, the die connecting part is located at one end of the die body, and one or more mounting holes are provided on the die connecting part. A connector is provided in the mounting hole, and the connector is used to fix the die on the first working platform.
[0013] In some implementations, the outer surface of the die body and the outer surface of the die connection are both cylindrical surfaces, and the diameter of the die connection is larger than the diameter of the die body.
[0014] In some implementations, the die body has a mating hole on the side facing the punch for insertion of the punch, and the die body has a visual opening that communicates with the mating hole.
[0015] In some implementations, the fixing structure is provided with one or more first connecting holes, and the die body is provided with one or more second connecting holes. The first connecting holes and the second connecting holes correspond one-to-one. The fixing member passes through the first connecting hole, the experimental plate and the second connecting hole corresponding to the first connecting hole in sequence, for fixing the experimental plate to the die body.
[0016] In some implementations, the fixing structure is annular, and a plurality of the first connecting holes are evenly spaced along the circumferential direction of the fixing structure.
[0017] A second aspect of this application provides a hole-expanding test apparatus, including a tensile testing machine and a plate hole-expanding test fixture as provided in any of the above aspects. The tensile testing machine includes a first working platform and a second working platform. The concave die of the plate hole-expanding test fixture is fixed on the first working platform of the tensile testing machine, and the convex die of the plate hole-expanding test fixture is fixed on the second working platform of the tensile testing machine.
[0018] In some implementations, the punch is detachably connected to the second working platform; and / or, the die is detachably connected to the first working platform.
[0019] In some implementations, the punch is threaded to the second working platform; and / or, the die is bolted to the first working platform.
[0020] The beneficial effects of this application are as follows: The plate hole expansion test fixture provided in this application includes a concave die, a convex die, and a fixing structure, which facilitates the installation of the plate hole expansion test fixture on a tensile testing machine to complete the hole expansion test instead of a cupping test machine, thereby reducing the cost of the hole expansion test; typically, a tensile testing machine is equipped with a force sensor that can detect sudden load drops, and the force sensor can be used to determine whether cracks occur at the edge of the hole in the test plate, thereby improving the accuracy of the detection. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 An exploded view of the plate hole expansion test fixture and the test plate provided in the embodiments of this application;
[0023] Figure 2 This is a schematic diagram of the structure of the plate hole expansion test fixture and the test plate provided in the embodiments of this application during the test process;
[0024] Figure 3 This is another exploded structural diagram of the plate hole expansion test fixture and the test plate provided in the embodiments of this application;
[0025] Figure 4 A diagram showing the relationship between displacement and load during a hole-reaming experiment using a hole-reaming experimental device provided in this application embodiment.
[0026] The following are the labeling elements in the figure:
[0027] 100 - Test fixture for enlarging holes in sheet metal; 200 - Test sheet metal;
[0028] 1-Die; 2-Punch; 3-Fixing structure; 4-Fixing component;
[0029] 101-Die body; 102-Die connection part;
[0030] 1011 - Mating hole; 1012 - Visual opening; 1013 - Second connecting hole;
[0031] 201 - Punch body; 202 - Punch connecting part;
[0032] 2011 - Cone tip;
[0033] 301 - First connecting hole;
[0034] 21 - Center punch. Detailed Implementation
[0035] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings. The embodiments described with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0036] In the description of this application, it should be understood that the terms "length", "width", "thickness", "top", "bottom", "inner", "outer", "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0037] To facilitate a clear description of the technical solutions of this application, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" do not necessarily imply that they are different.
[0038] In this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0039] In this application, "more than one" refers to a situation that includes one.
[0040] In this application, "and / or" is merely a way of describing the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0041] It should be noted that, in this application, the words "in one embodiment," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in one embodiment," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of words such as "in one embodiment," "exemplarily," and "for example" is intended to present the relevant concepts in a specific manner.
[0042] Please see Figures 1-3 , Figure 1 An exploded structural diagram of the plate hole expansion test fixture 100 and the test plate 200 provided in the embodiments of this application; Figure 2A schematic diagram of the structure of the plate hole expansion test fixture 100 and the test plate 200 provided in the embodiments of this application during the test process; Figure 3 Another exploded structural diagram of the plate hole expansion test fixture 100 and the test plate 200 provided in the embodiments of this application.
[0043] This application provides a sheet metal expansion test fixture 100 for use on a tensile testing machine. When the sheet metal expansion test fixture 100 is installed on a tensile testing machine, expansion tests can be performed, replacing the cupping test machine. By performing expansion tests on a tensile testing machine equipped with the sheet metal expansion test fixture 100, the flanging formability of thin metal sheets can be effectively evaluated, the relationship between expansion rate and edge cracking of stamped body panels can be explored, and quantitative indicators of sheet metal edge cracking can be obtained. This allows for effective quantitative identification of the risk of edge cracking in metal sheets, enabling modification and optimization of production processes.
[0044] Regarding tensile testing machines, for example, in one specific scenario, the tensile testing machine includes a support frame, a first working platform, and a second working platform. The support frame is supported on the first working platform, the first working platform is supported on the ground, and the second working platform is connected to the support frame, and the position of the second working platform on the support frame along the height direction is adjustable. For example, in another scenario, the tensile testing machine includes a support frame, a first working platform, and a second working platform, etc. The support frame can be supported on the ground, and both the first and second working platforms are connected to the support frame. The first working platform is located below or above the second working platform, and the position of both the second and first working platforms on the support frame along the height direction is adjustable.
[0045] The tooling 100 for the plate hole expansion test specifically includes a concave die 1, a convex die 2, and a fixing structure 3. Please refer to [link / reference]. Figures 1-3 The diagram illustrates the concave mold 1, the convex mold 2, and the fixing structure 3.
[0046] Please see Figure 1 The die 1 includes a die body 101 and a die connecting part 102 disposed on the die body 101. The die connecting part 102 is used to connect with the first working platform of the tensile testing machine. It can be understood that when it is necessary to fix the die 1 on the first working platform of the tensile testing machine, the die connecting part 102 can be used to connect to the first working platform.
[0047] In one example, the die body 101 is fixedly connected to the die connecting portion 102. For example, the die body 101 and the die connecting portion 102 are welded together. In other examples, the die body 101 and the die connecting portion 102 are detachably connected.
[0048] Please see Figure 3 The punch 2 includes a punch body 201 and a punch connecting part 202 disposed on the punch body 201. The punch connecting part 202 is used to connect with the second working platform of the tensile testing machine. It can be understood that when it is necessary to fix the punch 2 on the second working platform of the tensile testing machine, the punch connecting part 202 can be used to connect the second working platform; when the second working platform moves along the height direction, it can drive the punch 2 to move together along the height direction.
[0049] In one example, the punch connecting part 202 is integrally formed on the punch body 201; in other examples, the punch body 201 and the punch connecting part 202 are detachably connected.
[0050] Please see Figure 1 The diagram illustrates the fixing structure 3, which is detachably connected to the die body 101. The experimental plate 200 is fixed to the die body 101 by placing the fixing structure 3 between the fixing structure 3 and the die body 101 and fixing the fixing structure 3 to the die body 101. (See also...) Figure 2 This illustrates that the experimental plate 200 is clamped between the fixed structure 3 and the die body 101.
[0051] When the plate hole expansion test fixture 100 provided in this application embodiment is installed on a tensile testing machine, a hole expansion test can be performed on the tensile testing machine. Specifically, the test plate 200 is placed between the fixed structure 3 and the die body 101, and the fixed structure 3 is fixed on the die body 101. The test plate 200 has a central punch 21 in the middle, and the axis of the central punch 21 is collinear with the axis of the punch 2. If the position of the first working platform is fixed and the position of the second working platform along the height direction is adjustable, the second working platform can be controlled to move downward so that the punch 2 punches the test plate 200. Usually, a force sensor that can detect a sudden drop in load is provided on the second working platform. When the force sensor detects that the load suddenly drops by a certain value, the controller of the tensile testing machine determines that the edge of the central punch 21 of the test plate 200 has cracked, and controls the second working platform to stop moving, so that the punch 2 stops punching the test plate 200.
[0052] The force sensor detects a sudden drop in load, which can be understood as follows: during a tensile test using a tensile testing machine, the load detected by the force sensor initially increases gradually, and at a certain moment, the load detected by the force sensor suddenly decreases until the material breaks and the load detected by the force sensor becomes zero. When the plate hole-expanding test fixture 100 provided in this embodiment is installed on the tensile testing machine and a hole-expanding test is performed, the load detected by the force sensor initially increases gradually. When the force sensor detects a sudden drop in load, for example, a sudden drop of 20N, the controller of the tensile testing machine determines that the edge of the central punch 21 of the test plate 200 has cracked.
[0053] Please see Figure 4 , Figure 4 To obtain the displacement-load relationship diagram generated when performing a hole expansion test using a tensile testing machine with a 100mm hole expansion test fixture, in Figure 4 As can be seen from the two curves, the curve begins to decline when it rises to a certain height, that is, the load value suddenly decreases by a certain value. At this time, the controller of the tensile testing machine determines that the edge of the central punch 21 of the test plate 200 has cracked, and controls the punch 2 to stop punching the test plate 200.
[0054] In some traditional hole enlargement experiments, a camera is needed to observe the edge cracks of the central punch 21 on the experimental plate 200 and manually control the stop of the test, which inevitably causes the influence and error of human operation; however, in the embodiment of this application, the force sensor detects and the equipment automatically controls the stop of the test, eliminating the error caused by human control.
[0055] In this embodiment, by setting the plate hole expansion test fixture 100 including a concave mold 1, a convex mold 2 and a fixing structure 3, the plate hole expansion test fixture 100 can be easily installed on a tensile testing machine to complete the hole expansion test instead of a cupping test machine, thereby reducing the cost of the hole expansion test. Typically, a tensile testing machine is equipped with a force sensor that can detect sudden load drops. The force sensor can be used to determine whether cracks occur at the edge of the hole in the test plate 200, thereby improving the accuracy of the detection.
[0056] Regarding the punch 2, in one embodiment, please refer to... Figure 3 One end of the punch body 201 is a conical tip 2011, and the punch connecting part 202 is located at the end of the punch body 201 away from the conical tip 2011.
[0057] When the plate hole expansion test fixture 100 provided in this application embodiment is installed on a tensile testing machine, the cone tip 2011 is directly opposite the center punch 21 of the test plate 200 which is fixed between the fixed structure 3 and the die body 101.
[0058] Regarding the connection between the punch connecting part 202 and the second working platform, in one example, the punch connecting part 202 is threadedly connected to the second working platform.
[0059] In one specific embodiment, the punch connecting part 202 is provided with an external thread, and the second working platform is provided with an internal thread that mates with the punch connecting part 202, thereby achieving a threaded connection between the punch connecting part 202 and the second working platform. It should be noted that if the existing tensile testing machine's second working platform does not have an internal thread that mates with the punch connecting part 202, then an internal thread needs to be added to the second working platform. In another embodiment, the punch connecting part 202 is provided with an internal thread, and the second working platform is provided with an external thread that mates with the punch connecting part 202, thereby achieving a threaded connection between the punch connecting part 202 and the second working platform. It should be noted that if the existing tensile testing machine's second working platform does not have an external thread that mates with the punch connecting part 202, then an external thread needs to be added to the second working platform.
[0060] Please see Figure 3 The punch connecting portion 202 is located at the end of the punch body 201 away from the conical tip 2011, and the punch connecting portion 202 is cylindrical. In one specific embodiment, the end of the punch body 201 away from the conical tip 2011 is the connecting end, and the diameter of the connecting end is equal to the diameter of the punch connecting portion 202; in another specific embodiment, the end of the punch body 201 away from the conical tip 2011 is the connecting end, and the diameter of the connecting end is greater than the diameter of the punch connecting portion 202; in yet another specific embodiment, the end of the punch body 201 away from the conical tip 2011 is the connecting end, and the diameter of the connecting end is smaller than the diameter of the punch connecting portion 202.
[0061] In this embodiment, by setting the punch connection part 202 to be threadedly connected to the second working platform, the connection method between the punch connection part 202 and the second working platform can be simplified, and the punch 2 can be easily fixed on the second working platform of the tensile testing machine.
[0062] Regarding the connection between the punch connecting part 202 and the second working platform, in one embodiment, the punch connecting part 202 and the second working platform can be detachably connected by screws or bolts. In this case, connecting holes for the screws or bolts need to be provided on the punch connecting part 202 and the second working platform. In another embodiment, the punch connecting part 202 can be magnetically adsorbed on the second working platform. In this case, magnets need to be provided on the punch connecting part 202 and / or the second working platform. In yet another embodiment, the punch connecting part 202 can be snapped and fixed on the second working platform.
[0063] Regarding the connection between the die 1 and the first working platform, in one embodiment, the die connecting part 102 is located at one end of the die body 101. One or more mounting holes are provided on the die connecting part 102, and a connector is provided in the mounting hole. The connector passes through the mounting hole and is inserted into the first working platform to fix the die 1 on the first working platform.
[0064] In this embodiment, if the existing tensile testing machine does not have a socket for the connector on its first working platform, then a socket for the connector needs to be added to the first working platform.
[0065] Alternatively, the connector may be a screw or a bolt.
[0066] Optionally, the number of mounting holes is multiple, and the multiple mounting holes are evenly spaced along the circumferential direction of the die connection portion 102.
[0067] In this embodiment, by setting a connector to pass through the mounting hole and insert into the first working platform, the die 1 is fixed on the first working platform. The connection between the die 1 and the first working platform is simple, convenient to disassemble and assemble, and also facilitates the stable fixing of the die 1 on the first working platform.
[0068] Regarding the connection between the die 1 and the first working platform, in one embodiment, the die 1 is snapped into the first working platform, or the die 1 can be magnetically attached to the first working platform.
[0069] Regarding the shape of the die 1, in one embodiment, please refer to... Figure 1 The outer surface of the die body 101 and the outer surface of the die connecting part 102 are both cylindrical surfaces, and the diameter of the die connecting part 102 is larger than the diameter of the die body 101.
[0070] In this embodiment, the first working platform is preferably located below the second working platform. By setting the diameter of the die connecting part 102 to be larger than the diameter of the die body 101, the contact area between the die connecting part 102 and the first working platform can be increased, so as to stably fix the die 1 on the first working platform.
[0071] Regarding the die body 101, in one embodiment, please refer to... Figure 1 The die body 101 has a mating hole 1011 on the surface facing the punch 2 for inserting the punch 2. The die body 101 has a visual opening 1012, which is connected to the mating hole 1011.
[0072] Optionally, the mating hole 1011 is a through hole extending to both ends of the die body 101. In a specific example, the mating hole 1011 includes a first section and a second section. The first section is connected to the second section and the first section is located on the side of the second section away from the die connection part 102. The first section and the second section are coaxially arranged and the diameter of the first section is smaller than the diameter of the second section.
[0073] Optionally, the height of the die body 101 is greater than the height of the die connection portion 102.
[0074] In this embodiment, a visualization opening 1012 is provided on the die body 101 to facilitate observation of the deformation of the experimental plate 200.
[0075] Regarding the connection between the fixing structure 3 and the die body 101, in one embodiment, the fixing structure 3 is provided with one or more first connecting holes 301, and the die body 101 is provided with one or more second connecting holes 1013. The first connecting holes 301 and the second connecting holes 1013 correspond one-to-one. The fixing member 4 passes through the first connecting hole 301, the experimental plate 200, and the second connecting hole 1013 corresponding to the first connecting hole 301 in sequence, for fixing the experimental plate 200 to the die body 101. That is, in this embodiment, the experimental plate 200 is provided with one or more fixing holes, and the fixing holes correspond one-to-one with the first connecting holes 301, so that the fixing member 4 can pass through the fixing holes to the experimental plate 200.
[0076] Please see Figure 1 The diagram illustrates the first connecting hole 301 and the second connecting hole 1013. Preferably, the number of the first connecting hole 301 and the number of the second connecting hole 1013 are the same, with each first connecting hole 301 corresponding to one second connecting hole 1013.
[0077] Preferably, the fixing structure 3 is provided with a plurality of first connecting holes 301, and the plurality of first connecting holes 301 are distributed at intervals along the circumferential direction of the fixing structure 3.
[0078] Preferably, the fastener 4 is a screw or bolt.
[0079] In this embodiment, by setting the fixing member 4 to pass through the first connecting hole 301, the experimental plate 200 and the corresponding second connecting hole 1013 in sequence, the experimental plate 200 is fixed on the die body 101. This not only simplifies the connection method and facilitates the assembly and disassembly of the experimental plate 200, but also enables the experimental plate 200 to be positioned on the die body 101, so that the conical tip 2011 of the punch 2 is directly opposite the center punch hole 21 of the experimental plate 200.
[0080] Regarding the shape of the fixing structure 3, in one embodiment, please refer to... Figure 1The fixing structure 3 is in the shape of a ring, and multiple first connecting holes 301 are evenly distributed along the circumferential direction of the fixing structure 3.
[0081] Optionally, the outer diameter of the fixed structure 3 is equal to the outer diameter of the die body 101.
[0082] Optionally, the diameter of the opening formed by the mating hole 1011 on the top surface of the die body 101 is equal to the inner diameter of the fixing structure 3.
[0083] For a specific example, please see Figure 1 The fixed structure 3 is provided with three first connecting holes 301, which are evenly spaced along the circumferential direction of the fixed structure 3; the die body 101 is provided with three second connecting holes 1013, which are spaced along the circumferential direction of the die body 101. For example, the three second connecting holes 1013 are evenly distributed along the circumferential direction of the die body 101.
[0084] The circular fixing structure 3 provided in this embodiment is simple in structure and convenient to process and manufacture.
[0085] This application provides a hole expansion test device, including a tensile testing machine and a plate hole expansion test fixture 100 provided in any of the above embodiments. The tensile testing machine includes a first working platform and a second working platform. The concave mold 1 of the plate hole expansion test fixture 100 is fixed on the first working platform of the tensile testing machine, and the convex mold 2 of the plate hole expansion test fixture 100 is fixed on the second working platform of the tensile testing machine.
[0086] In one example, the tensile testing machine further includes a support frame supported on a first working platform, which is supported on the ground. A second working platform is connected to the support frame and its position on the support frame is adjustable in the height direction. In other examples, the tensile testing machine further includes a support frame that can be supported on the ground. Both the first and second working platforms are connected to the support frame. The first working platform is positioned below or above the second working platform. The position of both the second and first working platforms on the support frame is adjustable in the height direction.
[0087] Optionally, a force sensor capable of detecting sudden load drops is installed on the second working platform. When the force sensor detects that the load has suddenly dropped by a certain value, the controller of the tensile testing machine determines that the edge of the central punch 21 of the test plate 200 has cracked. The controller then controls the first working platform and / or the second working platform to stop working, so as to stop the punch 2 from punching the test plate 200.
[0088] The hole expansion test equipment provided in this application embodiment can complete the hole expansion test, thereby replacing the cupping test machine and reducing the cost of the hole expansion test; the tensile test machine is equipped with a force sensor that can determine the sudden drop in load, which can be used to determine the situation of cracking at the edge of the 200 holes in the test plate, thereby improving the accuracy of the detection.
[0089] In one embodiment, the punch 2 is detachably connected to the second working platform to facilitate the replacement of the punch 2. Preferably, the punch 2 is threadedly connected to the second working platform.
[0090] In one embodiment, the die 1 is detachably connected to the first working platform to facilitate the replacement of the die 1. Preferably, the die 1 is connected to the first working platform by bolts.
[0091] The hole enlargement test equipment provided in this application embodiment is compared with the cupping test machine in the prior art in a hole enlargement test, as follows:
[0092] Example 1: Using the hole-expanding experimental equipment provided in this application, an aluminum alloy sheet with three fixed threaded holes, a 3% clearance center punch, a size of 100mm × 100mm, and a thickness of 0.85mm was processed as the experimental sheet 200. The experimental sheet 200 was fixed to the die 1 using the fixing structure 3. The stopping condition was set to a sudden drop in load of 30N detected by the force sensor. The hole-expanding rate was 10mm / min, and three sets of tests were conducted. The 3% clearance center punch refers to the clearance value between the punch 2 and the die 1 being 3% of the material thickness during the punching process; the hole-expanding rate refers to the change in hole-expanding size (such as the increase in hole diameter or hole-expanding depth) per unit time during the hole-expanding test or actual hole-expanding process.
[0093] Example 2: Using the hole expansion test equipment provided in this application, an aluminum alloy plate with three fixed threaded holes, a 6% clearance center punch, a size of 100mm×100mm, and a thickness of 1.5mm was processed. The test plate 200 was fixed on the die 1 using the fixing structure 3. The stopping condition was set to the force sensor detecting a sudden drop in load of 30N. The hole expansion rate was 10mm / min. Three sets of tests were conducted.
[0094] Example 3: Using the hole expansion test equipment provided in this application, a cold-rolled duplex steel plate with three fixed threaded holes, a 6% clearance center punch, a size of 100mm×100mm, and a thickness of 1.2mm was processed. The test plate 200 was fixed to the die 1 using the fixing structure 3. The stopping condition was set to the force sensor detecting a sudden drop in load of 30N. The hole expansion rate was 10mm / min. Three sets of tests were conducted.
[0095] Example 4: Using the hole-expanding test equipment provided in this application, a cold-rolled duplex steel plate with three fixed threaded holes, a 6% clearance center punch, a size of 100mm×100mm, and a thickness of 1.5mm was processed. The test plate 200 was fixed to the die 1 using the fixing structure 3. The stopping condition was set to the load drop of 40N detected by the force sensor. The hole-expanding rate was 10mm / min. Three sets of tests were conducted.
[0096] Comparative Example 1: The test was conducted using a cupping tester specifically designed for hole expansion testing. Cracks at the hole edge were monitored based on real-time video signals from a camera. The experimental material was a 0.85mm thick aluminum alloy sheet with a 3% clearance center punch, measuring 100mm x 100mm. The hole expansion rate was 10mm / min, and three sets of tests were performed.
[0097] Comparative Example 2: Using the hole-expanding test equipment provided in the embodiments of this application, an aluminum alloy plate with three fixed threaded holes, a 3% clearance center punch, a size of 100mm×100mm, and a thickness of 1.5mm was processed. The test plate 200 was fixed on the die 1 using the fixing structure 3. The stopping condition was set to the force sensor detecting a sudden drop in load of 20N. The hole-expanding rate was 10mm / min. Three sets of tests were conducted.
[0098] Comparative Example 3: Using the hole-expanding test equipment provided in the embodiments of this application, an aluminum alloy plate with three fixed threaded holes, a 3% clearance center punch, a size of 100mm×100mm, and a thickness of 0.85mm was processed. The test plate 200 was fixed on the die 1 using the fixing structure 3. The stopping condition was set to the force sensor detecting a sudden drop in load of 20N. The hole-expanding rate was 10mm / min. Three sets of tests were conducted.
[0099] Comparative Example 4: Using the hole-expanding test equipment provided in the embodiments of this application, an aluminum alloy plate with three fixed threaded holes, a 12% clearance center punch, a size of 100mm×100mm, and a thickness of 0.85mm was processed. The test plate 200 was fixed on the die 1 using the fixing structure 3. The stopping condition was set to the force sensor detecting a sudden drop in load of 20N. The hole-expanding rate was 30mm / min. Three sets of tests were conducted.
[0100] The porosity of the examples and comparative examples was measured and calculated after the experiments were completed, as shown in the table below:
[0101] Table 1. Pore Enlargement Rate of Examples and Comparative Examples after Experimentation
[0102] Specimen Hole expansion ratio 1 (%) Hole expansion ratio 2 (%) Hole expansion ratio 3 (%) Average hole expansion ratio (%) Example 1 35.6 36.2 35.8 35.9 Example 2 44.5 45.2 44.7 44.8 Example 3 27.1 27.6 27.2 27.3 Example 4 24.6 24.7 25.1 24.8 Comparative Example 1 36.1 35.4 36.0 35.8 Comparative Example 2 46.6 47.8 46.2 46.9 Comparative Example 3 32.5 33.2 33.5 33.1 Comparative Example 4 34.1 34.0 35.1 34.4
[0103] The table above leads to the conclusion that, by comparing Example 1 with Comparative Example 1, it can be shown that the hole enlargement test equipment proposed in this application has high accuracy and can replace the traditional cupping test machine.
[0104] By comparing Examples 2, 3, and 4 with Comparative Examples 2, 3, and 4, respectively, a quantitative relationship of the porosity of alloy plates with different alloys, plate thicknesses, and clearances can be obtained. This facilitates the subsequent establishment of an effective database of the porosity of alloy plates, the study of its theoretical relationship with edge cracking of sheet metal stampings, and the accurate prediction of the edge cracking state of sheet metal.
[0105] In summary, the hole enlargement experimental device provided in this application has the following advantages:
[0106] 1. This utility model allows for testing using a common tensile testing machine, rather than using specialized pore-expanding equipment such as a cupping test machine, making this pore-expanding testing method applicable to most research institutions.
[0107] 2. This utility model can avoid the influence and error caused by human operation. The traditional hole expansion test method requires a camera to observe the crack formation and then manually control the stop of the test. This utility model uses instrument control to stop the test, eliminating the error caused by human control.
[0108] 3. This utility model is convenient and quick to operate, does not require a large learning cost for experimental operation, is easy to conduct and inexpensive to conduct, and can carry out a large number of hole enlargement tests in a short time, which can fully meet production requirements.
[0109] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A hole-reaming experimental apparatus, characterized in that, The system includes a tensile testing machine and a plate hole expansion testing fixture (100), wherein the tensile testing machine includes a first working platform and a second working platform, and the plate hole expansion testing fixture includes: The die (1) includes a die body (101) and a die connecting part (102) disposed on the die body (101), the die connecting part (102) being connected to the first working platform; The punch (2) includes a punch body (201) and a punch connecting part (202) disposed on the punch body (201). The punch connecting part (202) is connected to the second working platform. A force sensor capable of determining a sudden drop in load is disposed on the second working platform. The fixing structure (3) is detachably mounted on the die (1) for fixing the plate (200) on the die body (101).
2. The hole-reaming experimental apparatus as described in claim 1, characterized in that, One end of the punch body (201) is a conical tip (2011), and the punch connecting part (202) is located at the end of the punch body (201) away from the conical tip (2011).
3. The hole-reaming experimental apparatus as described in claim 1 or 2, characterized in that, The punch connecting part (202) is threadedly connected to the second working platform.
4. The hole enlargement experimental apparatus as described in claim 1, characterized in that, The die connecting part (102) is located at one end of the die body (101). One or more mounting holes are provided on the die connecting part (102). A connector is provided in the mounting hole. The connector is used to fix the die (1) on the first working platform.
5. The hole-reaming experimental apparatus as described in claim 1, characterized in that, The die body (101) has a mating hole (1011) on the side facing the punch (2) for inserting the punch (2). The die body (101) has a visual opening (1012) that is connected to the mating hole (1011).
6. The hole enlargement experimental apparatus as described in claim 1, characterized in that, The fixing structure (3) is provided with one or more first connecting holes (301), and the die body (101) is provided with one or more second connecting holes (1013). The first connecting holes (301) and the second connecting holes (1013) correspond one-to-one. The fixing member passes through the first connecting hole (301), the plate (200) and the second connecting hole (1013) corresponding to the first connecting hole (301) in sequence to fix the experimental plate (200) on the die body (101).
7. The hole enlargement experimental apparatus as described in claim 6, characterized in that, The fixing structure (3) is annular, and a plurality of the first connecting holes (301) are spaced apart along the circumferential direction of the fixing structure (3).
8. The hole enlargement experimental apparatus as described in claim 1, characterized in that, The punch (2) is detachably connected to the second working platform; and / or the die (1) is detachably connected to the first working platform.
9. The hole-reaming experimental apparatus as described in claim 1, characterized in that, The punch (2) is threaded to the second working platform; and / or the die (1) is bolted to the first working platform.