A tensile testing device for metal wire

Abstract

This utility model relates to a tensile testing device for metal wire, belonging to the field of materials mechanics testing equipment. The device includes a wedge-shaped connecting rod (3) and a winding post (6). One end of the winding post (6) is connected to the small end of the wedge-shaped connecting rod (3). A wire-passing hole (8) is provided in the middle of the winding post (6) away from the wedge-shaped connecting rod (3). The other end of the wire-passing hole (8) passes through the interior of the winding post (6) and exits along the outer wall of the winding post (6). A limiting hole (31) is provided at the connecting end of the wedge-shaped connecting rod (3). This device uses a winding friction clamping structure to replace the traditional rigid jaw clamp, significantly improving the effectiveness, stability, and repeatability of the tensile test of metal wire. It solves the problem of non-gauge section fracture caused by excessive clamping rigidity, stress concentration, or slippage of the metal wire sample in the prior art.

Description

Technical Field

[0001] This utility model relates to a tensile testing device for metal wires, belonging to the field of materials mechanics testing equipment. Background Technology

[0002] Metal wires are widely used in high-tech fields such as electronic devices, aerospace, precision manufacturing, and new energy equipment. Reliable assessment of their mechanical properties is crucial for product quality control and engineering design. Tensile testing is one of the key methods for evaluating the mechanical properties of wires, especially the determination of parameters such as yield strength, ultimate strength, and elongation. In tensile testing, it is essential to ensure that the wire breaks within the gauge length to obtain valid experimental data.

[0003] However, due to the typically small diameter, smooth surface, and high flexibility of metal wires, slippage, localized crushing, or stress concentration can easily occur in the clamp, causing the fracture location to deviate from the gauge length and severely affecting the validity of the test. Currently, various clamping structure solutions have been proposed to address this issue.

[0004] In the prior art, patent CN202320044471 discloses a tensile testing fixture for silver alloy wire. This fixture achieves adjustable clamping of the wire by using a rotating base, threaded column, lifting rod, and a vertically movable inclined slider. This structure offers a certain degree of adjustability and applicability. However, it still primarily relies on a clamping and biting method, which carries the risk of indentation or even shear breakage on smooth or soft wires, making it difficult to completely prevent clamping end failure. Similarly, patent CN202010875245 proposes a tensile fixture for irregularly shaped wires. It enhances clamping force by using a spiral threaded groove and a grooved pressure block, making it suitable for wires with various cross-sectional shapes. While this solution has good versatility, its clamping structure relies on a tight fit between the clamping block and the groove. For standard round wires, it may still suffer from excessive clamping rigidity and stress concentration, and it is difficult to quickly adapt to wires of different lengths and diameters.

[0005] In summary, existing technologies still have certain limitations in terms of clamping methods, adaptability, and stress distribution optimization. There is a lack of a dedicated tensile testing fixture for wires that simultaneously offers strong anti-breakage capability, stable clamping, easy installation and operation, and wide applicability. Therefore, there is an urgent need to develop a new structure to effectively alleviate stress concentration at the wire clamping end and improve the validity and consistency of tensile test data. Utility Model Content

[0006] The technical problem to be solved by this utility model is the fracture of the non-gauge section caused by excessive clamping rigidity, stress concentration or slippage of the metal wire sample in the prior art.

[0007] The technical solution adopted by this utility model to solve its technical problem is: a tensile testing device for metal wire, including a wedge-shaped connecting rod and a winding column. One end of the winding column is connected to the small end of the wedge-shaped connecting rod. A wire-passing hole is provided in the middle of the end of the winding column away from the wedge-shaped connecting rod. The other end of the wire-passing hole passes into the interior of the winding column and exits along the outer wall of the winding column. A limit hole is provided at the connecting end of the wedge-shaped connecting rod.

[0008] In the aforementioned device, the wire-threading hole extends tangentially along the winding post away from the end of the wedge-shaped connecting rod.

[0009] In the above-mentioned device, the threading hole is spiral-shaped.

[0010] In the above-mentioned device, the wire-threading hole is arc-shaped.

[0011] In the aforementioned device, the wire-threading hole is provided with a sleeve at the end face of the winding post.

[0012] In the aforementioned device, the winding post is threadedly connected to the wedge-shaped connecting rod.

[0013] Furthermore, the winding post end of the device described above is provided with a threaded hole away from the wire-passing hole, and the small end of the wedge-shaped connecting rod is provided with an external thread.

[0014] In the aforementioned device, at least two parallel surfaces are provided on the outer wall of the winding post.

[0015] Furthermore, the winding post in the above-mentioned device is provided with a hexagonal twisting part on its outer wall.

[0016] The device also includes a locking nut, which is fitted onto the wedge-shaped connecting rod and threadedly connected to it.

[0017] The beneficial effects of this utility model are: (1) Avoid breakage of clamping end and improve test effectiveness: By adopting the dual positioning method of winding post + limiting hole, the traditional rigid jaw clamp is replaced by a winding friction clamping structure, which effectively avoids the problem of non-gauge section breakage caused by stress concentration at the clamping end, and significantly improves the success rate and data validity of tensile test.

[0018] (2) Simple structure and easy assembly: The overall structure is composed of standard parts and customized parts, which is easy to process, assemble and maintain. It is suitable for direct replacement or addition on the existing universal material testing machine platform, and has good versatility and promotion.

[0019] (3) Uniform stress distribution and more reliable data: The winding post adopts a spiral threading hole design, which makes the winding path of the wire have a natural guiding function, effectively achieving uniform stress distribution, avoiding stress concentration, and ensuring the repeatability and accuracy of test data.

[0020] (4) Strong material protection: By setting a soft metal sleeve at the wire outlet of the winding post, the wire material is clamped while avoiding scratches and damage to its surface.

[0021] (5) Easy to operate and highly adaptable to personnel: The clamping process does not rely on complex tools or high operational proficiency, which lowers the operating threshold for test personnel and facilitates rapid deployment and large-scale application.

[0022] (6) Wide range of applications: This device is suitable for tensile testing of various metal wires, alloy wires, etc., and is especially suitable for promotion and use in scientific research units, enterprise laboratories and third-party testing institutions. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] Figure 2 This is a schematic diagram of the winding post of this utility model.

[0025] Figure 3 This is a top view of the structure of the winding post of this utility model.

[0026] In the diagram: 1. Crossbeam; 2. Base; 3. Wedge-shaped connecting rod; 31. Limiting hole; 4. Locking nut; 5. Metal wire; 6. Winding post; 61. Tightening part; 62. Threaded hole; 7. Sleeve; 8. Threading hole. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] like Figures 1 to 3As shown, this utility model discloses a tensile testing device for metal wire, including a wedge-shaped connecting rod 3 and a winding post 6. One end of the winding post 6 is connected to the small end of the wedge-shaped connecting rod 3. A wire-passing hole 8 is provided in the middle of the end of the winding post 6 away from the wedge-shaped connecting rod 3. The other end of the wire-passing hole 8 passes through the interior of the winding post 6 and exits along the outer wall of the winding post 6. A limiting hole 31 is provided at the connecting end of the wedge-shaped connecting rod 3. Those skilled in the art will understand that this device is based on an existing universal testing machine, and the wedge-shaped connecting rod 3 is a component of the original universal testing machine. The large end of the wedge-shaped connecting rod 3 is directly connected to the base 2, which is the tensile base of the universal testing machine, used to install and support the sample clamping fixture. This device fully utilizes the wedge-shaped structural characteristics of the base 2, and designs and installs a precisely matched wedge-shaped connecting rod 3, thereby ensuring good structural rigidity and positioning accuracy during fixture assembly, and improving test stability and repeatability. The lower end of the base 2 is connected to the crossbeam 1, which is the crossbeam assembly of the universal tensile testing machine. It is mainly used to support the fixture and perform vertical displacement movements during the tensile test. The fixture structure is symmetrically arranged vertically, so the crossbeam 1 includes an upper crossbeam and a lower crossbeam. The lower crossbeam is usually fixed, while the upper crossbeam moves upwards during the tensile process, causing the fixture and the sample to move synchronously to complete the tensile loading process of the metal wire 5. The large end of the wedge-shaped connecting rod 3 is a wedge-shaped structure used for precise fit and stable installation with the base 2; the small end is a cylindrical screw structure used to connect the winding post 6. A limiting hole 31 is also provided on the wedge-shaped connecting rod 3 for threading and positioning the metal wire 5 to prevent slippage during loading. The winding post 6 is mainly used to wind and fix the metal wire 5, and one end of it is connected to the wedge-shaped connecting rod 3. The winding post 6 has a wire-passing hole inside. The bending section of the wire-passing hole should be smoothly transitioned to facilitate easy insertion, while ensuring that the metal wire 5 is evenly stressed so that the test results are more accurate.

[0029] Preferably, in the above-described device, the end of the wire-threading hole 8 away from the wedge-shaped connecting rod 3 extends tangentially along the winding post 6. Those skilled in the art will understand that, since the metal wire 5 needs to be wound 2 to 3 times around the outer wall of the winding post 6 after exiting through the wire-threading hole 8, to facilitate winding, this device further preferably has the end of the wire-threading hole 8 away from the wedge-shaped connecting rod 3 extending tangentially along the winding post 6. This structural arrangement allows the metal wire 5 to be directly wound around the outer wall of the winding post 6 after exiting through the wire-threading hole 8, avoiding excessive bending that could affect the experimental structure.

[0030] Preferably, the wire-threading hole 8 in the above-mentioned device is spiral-shaped. Those skilled in the art will understand that the preferred spiral shape of the wire-threading hole 8 in this device facilitates the smooth guidance and insertion of the metal wire 5, improving clamping efficiency; furthermore, it helps to ensure uniform stress distribution on the metal wire 5 during the stretching process, avoiding localized stress concentration and thus reducing the risk of breakage in non-gauge sections.

[0031] Preferably, the threading hole 8 in the above-described device is arc-shaped. Those skilled in the art will understand that the threading hole 8 is preferably arc-shaped to avoid excessive bending that could affect experimental accuracy.

[0032] Preferably, in the above-described device, a sleeve 7 is provided at the end face of the winding post 6 for the wire threading hole 8. Those skilled in the art will understand that this is to provide flexible contact with the surface of the metal wire 5 during the stretching process, avoiding scratches or indentations. Preferably, the sleeve 7 is provided at the end face of the winding post 6 for the wire threading hole 8. Preferably, the sleeve 7 is made of a relatively soft metal material such as copper or aluminum, to balance protection and structural support.

[0033] Preferably, the winding post 6 in the above-described device is threadedly connected to the wedge-shaped connecting rod 3. Those skilled in the art will understand that, for ease of connection between the winding post 6 and the wedge-shaped connecting rod 3, a threaded connection between the winding post 6 and the wedge-shaped connecting rod 3 is actually preferred.

[0034] Preferably, in the above-mentioned device, the end of the winding post 6 away from the wire-passing hole is provided with a threaded hole 62, and the small end of the wedge-shaped connecting rod 3 is provided with an external thread. Those skilled in the art will understand that, more preferably, the winding post 6 is provided with a threaded hole 62 away from the wire-passing hole, and the small end of the wedge-shaped connecting rod 3 is provided with an external thread, so that the winding post 6 and the wedge-shaped connecting rod 3 are directly connected by the external thread and the threaded hole 62.

[0035] Preferably, the outer wall of the winding post 6 in the above-mentioned device has at least two parallel surfaces. Those skilled in the art will understand that since the wedge-shaped connecting rod 3 is directly connected to the base 2, actual tightening requires rotating the winding post 6. To facilitate the screwing in of the winding post 6, this device preferably has at least two parallel surfaces on the outer wall of the winding post 6, making it convenient for the wrench's open end to engage.

[0036] Preferably, the winding post 6 in the above-mentioned device is provided with a hexagonal screwing part 61 on its outer wall. It will be understood by those skilled in the art that the device is further preferably provided with a hexagonal screwing part 61 on its outer wall. In practice, the screwing part 61 is preferably hexagonal nut shaped and is directly sleeved on the end of the winding post 6 away from the wedge-shaped connecting rod 3.

[0037] Preferably, the above-mentioned device further includes a locking nut 4, which is sleeved on the wedge-shaped connecting rod 3 and threadedly connected to the wedge-shaped connecting rod 3. Those skilled in the art will understand that, in order to ensure a tight connection between the winding post 6 and the wedge-shaped connecting rod 3, and to achieve fine-tuning of the length, the locking nut 4 is preferably installed at the small end of the wedge-shaped connecting rod 3, and is mainly used to axially lock the winding post 6 to prevent it from rotating during the tensile test, thereby ensuring the stability of the test loading process and the accuracy of the data.

[0038] The operation steps are as follows: (1) Equipment preparation: Confirm that the universal testing machine is powered on and functioning normally, level the upper and lower crossbeams 1, and complete the installation of the fixture assembly.

[0039] (2) Sample pretreatment: Select 5 metal wire samples of compliant length, verify that there are no obvious defects on their surface, and measure the gauge length.

[0040] (3) Threading and winding: Thread the metal wire 5 through the threading hole 8 at the end of the winding post 6; after it is pulled out from the side wall, wind it 2 to 3 times along the spiral groove outside the winding post 6; after winding, it is pulled out through the limiting hole 31 provided on the wedge connecting rod 3; tighten the metal wire 5 to ensure that it is basically in a pre-tight straight state under tension.

[0041] (4) Install sleeve 7: Confirm that flexible sleeve 7 has been installed at the wire hole 8 at the end of the winding post 6 to prevent the metal wire 5 from being damaged by the metal edge during the stress process.

[0042] (5) Locking and fixing: Tighten the locking nut 4 to ensure that the winding post 6 and the wedge-shaped connecting rod 3 are tightly connected and there is no looseness.

[0043] (6) Symmetrical clamping: Fix the other end of the metal wire 5 to the upper clamp in the same way to achieve symmetrical clamping.

[0044] (7) Loading test: Set test parameters (such as tensile rate and termination conditions); start the testing machine and conduct tensile test; observe whether the specimen breaks within the gauge length and record relevant data.

[0045] (8) Disassembly and cleaning: After the test is completed, unload slowly; remove the sample fragments and check the clamps for damage; clean the device.

[0046] Example 1: Tensile test of titanium wire 1. Test materials: TA1 pure titanium wire, diameter 1.5 mm, original gauge length 50 mm.

[0047] 2. Experimental Procedure: (1) Adjust the universal testing machine to the standard tensile mode and install the fixture device of this utility model.

[0048] (2) Take a TA1 titanium wire sample of appropriate length, confirm that there are no creases or oil stains on the surface, and mark 50mm in the center section using a gauge ruler.

[0049] (3) Insert the metal wire 5 through the wire hole 8 at the end of the winding post 6 of the lower clamp, lead it out from the side wall, wind it 2.5 times on the surface of the post, and then pass it out through the limiting hole 31 of the wedge-shaped connecting rod 3.

[0050] (4) Confirm that the soft aluminum sleeve 7 has been installed at the end of the winding post 6, and tighten the locking nut 4 to complete the lower end clamping.

[0051] (5) Thread the other end of the metal wire 5 through the upper clamp in the same way to achieve symmetrical clamping.

[0052] (6) Set the stretching rate to 2 mm / min and start loading.

[0053] (7) The specimen breaks at the gauge length, the fracture surface is neat, the tensile curve is stable, and the test data is valid.

[0054] 3. Results: This embodiment verifies that the clamping structure of this utility model has good clamping stability for medium-hard titanium wire with a diameter of 1.5 mm, avoids end breakage, and is easy to operate with good repeatability.

[0055] Example 2: Tensile test of high-temperature alloy wire 1. Test material: GH4169 nickel-based high-temperature alloy wire, diameter 1.0 mm, gauge length 30 mm.

[0056] 2. Experimental steps: (1) Use the same universal testing machine and fixture configuration as in Example 1.

[0057] (2) Take a GH4169 metal wire sample 5, confirm the diameter with a vernier caliper, and stamp the two ends of the gauge with a micro steel stamp.

[0058] (3) Insert the metal wire 5 through the wire hole 8 at the end of the winding post 6, lead it out through the side wall, wind it about 2 turns, and then pass it out through the limiting hole 31.

[0059] (4) Care should be taken during the threading process to avoid twisting or scratching the metal wire 5; a copper flexible sleeve 7 should be installed at the end of the winding post 6 for protection.

[0060] (5) Clamp the other end along the same path and confirm that the upper and lower clamps are straight and symmetrical.

[0061] (6) Set the loading speed to 1 mm / min and start the test.

[0062] (7) The fracture location of the specimen is located in the middle of the gauge length. The tensile curve shows typical elastic-plastic deformation behavior. The data curve is smooth and no abnormal noise is observed.

[0063] 3. Results: GH4169 is a material with high hardness and high deformation resistance. The clamping structure of this utility model maintained good centering and clamping stability during the tensile process. The sample did not break in the clamping area or the wire outlet, which verifies the adaptability and practicality of the clamp to high-strength metal wire 5.

Claims

1. A tensile testing device for metal wire, comprising a wedge-shaped connecting rod (3), characterized in that: It also includes a winding post (6), one end of which is connected to the small end of the wedge-shaped connecting rod (3). A wire-passing hole (8) is provided in the middle of the end of the winding post (6) away from the wedge-shaped connecting rod (3). The other end of the wire-passing hole (8) passes into the inside of the winding post (6) and passes out along the outer wall of the winding post (6). A limit hole (31) is provided at the end of the wedge-shaped connecting rod (3).

2. The tensile testing device for metal wire according to claim 1, characterized in that: The wire-threading hole (8) extends tangentially along the winding post (6) from the end away from the wedge-shaped connecting rod (3).

3. The tensile testing device for metal wire according to claim 1, characterized in that: The threading hole (8) is spiral-shaped.

4. The tensile testing device for metal wire according to claim 1, characterized in that: The threading hole (8) is arc-shaped.

5. The tensile testing device for metal wire according to claim 1, characterized in that: The threading hole (8) is provided with a sleeve (7) at the end face of the winding post (6).

6. The tensile testing apparatus for metal wire according to claim 1, characterized in that: The winding post (6) is threadedly connected to the wedge-shaped connecting rod (3).

7. The tensile testing apparatus for metal wire according to claim 6, characterized in that: The winding post (6) has a threaded hole (62) at the end away from the wire hole, and the small end of the wedge-shaped connecting rod (3) has an external thread.

8. The tensile testing device for metal wire according to claim 1, characterized in that: At least two parallel surfaces are provided on the outer wall of the winding post (6).

9. The tensile testing apparatus for metal wire according to claim 8, characterized in that: The winding post (6) has a hexagonal twisting part (61) on its outer wall.

10. The tensile testing apparatus for metal wire according to claim 1, characterized in that: It also includes a locking nut (4), which is sleeved on the wedge-shaped connecting rod (3) and threadedly connected to the wedge-shaped connecting rod (3).

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