Clamp for delayed cracking test of super-strong steel of automobile

Abstract

A clamp for an automobile super-strong steel delayed cracking test comprises a fixed clamping block, a movable clamping block, an adjusting screw rod, two positioning pins and a screwing nut, the fixed clamping block is fixed at one end of the adjusting screw rod through a fixing nut, one end of each positioning pin is fixed on the fixed clamping block and arranged on two sides of the adjusting screw rod, and the other end of each positioning pin is fixed on the movable clamping block. The other ends of the two positioning pins penetrate through positioning holes in the movable clamping block and are connected with the movable clamping block in a sliding mode, the movable clamping block is connected with the adjusting screw rod in a sliding mode, the screwing nut is arranged on the outer side of the movable clamping block and is in threaded connection with the adjusting screw rod, and a wedge-shaped clamping groove is formed in the side, opposite to the fixed clamping block, of the movable clamping block. And the structure of the fixed clamping block is the same as that of the movable clamping block. The split type clamp is small in size, small in occupied space, capable of reducing acid consumption and convenient to disassemble.

Description

Technical Field

[0001] This utility model relates to a fixture for delayed cracking testing of steel, and more particularly to a fixture for delayed cracking testing of automotive ultra-strong steel. Background Technology

[0002] The delayed cracking test by immersion in hydrochloric acid solution (hereinafter referred to as the delayed cracking test) is one of the main methods to characterize the delayed cracking performance of ultra-high strength steel materials. Conducting a sheet-level delayed cracking test can reflect the influence of material composition and internal stress on corrosion resistance, and is an important reference for component-level product materials.

[0003] Currently, the main testing methods are for raw materials. When the bending angle is too large, only a rough assessment and comparison of the raw materials can be made. However, for specific product parts, which have fixed bending angles and bending radius, current assessment methods cannot simulate the stress state of the actual product parts, thus failing to determine the delayed cracking performance under the actual product part's condition. This makes it impossible to conduct risk assessment before product development. Patent 202120014546.8 discloses a bending device for a high-strength automotive steel plate delayed cracking test sample, which includes a vise, a bending fixture, and an adjusting clamp (20). The vise includes a fixed jaw (1), a movable jaw (2), a jaw shoulder (3), a vise handle (5), a jaw fixing bracket (6), and jaw screws (4). The bending fixture includes a sleeve (13), an upper clamping block (10), a rotating shaft seat (36), and a lower clamping block (12). The adjusting clamp ( 20) includes clamping plate (40), clamping plate platform (39), adjusting screw (21), clamping plate clip (22), clamping plate clip hole (23), adjusting screw hole (24), sample clip hole (25), etc. Its bending device has a complex structure and is mainly used for bending steel plates. First, the test sample is bent using a bench vise, and then the bending is continued using the adjusting clamping plate. Then, a delayed cracking test is performed. Its operation process is complicated, and the adjusting clamping plate is large in volume. Immersing it in acid will cause unnecessary acid consumption. Utility Model Content

[0004] To overcome the shortcomings of the prior art, this utility model provides a fixture for delayed cracking tests on automotive ultra-strong steel. The pre-bent sheet is placed in the fixture, and after applying a pre-tightening force to clamp it, the fixture and the sheet are simultaneously placed in acid. The overall fixture has a small volume and occupies little space, reducing acid consumption.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A fixture for delayed cracking testing of automotive high-strength steel includes a fixed clamping block, a movable clamping block, an adjusting screw, locating pins, and a tightening nut. The fixed clamping block is fixed to one end of the adjusting screw by a fixing nut. Two locating pins are provided, one on each side of the adjusting screw. One end of each locating pin is fixed to the fixed clamping block, and the other end passes through a locating hole on the movable clamping block, forming a slidable connection. The movable clamping block is slidably connected to the adjusting screw. The tightening nut is located on the outside of the movable clamping block and is threadedly connected to the adjusting screw. A wedge-shaped groove is provided on the side of the movable clamping block opposite to the fixed clamping block. The fixed clamping block has the same structure as the movable clamping block.

[0007] The aforementioned fixture for delayed cracking testing of automotive high-strength steel further includes a tightening sleeve comprising a sleeve body, a compression spring, a ball bearing, and a screw. The sleeve body is concave and fits onto the outer wall of the tightening nut. A through hole is provided on the side wall of the sleeve body, the top diameter of which is smaller than the diameter of the ball bearing. The compression spring is disposed in the through hole, and the ball bearing is disposed on top of the compression spring. The top of the ball bearing protrudes from the top of the through hole and matches and contacts a spherical groove on the outer wall of the tightening nut. The center of the ball bearing is lower than the top of the through hole. The screw is fixed to the bottom of the through hole. The bottom center of the sleeve body is connected to the adjusting screw with clearance. The tightening nut is a round nut, and washers are provided between the tightening nut and the moving clamp block, and between the tightening nut and the sleeve body.

[0008] The aforementioned fixture for delayed cracking testing of automotive high-strength steel has wedge-shaped slots at both the upper and lower ends of the moving clamping block, and two corresponding wedge-shaped slots on the fixed clamping block.

[0009] The aforementioned fixture used for delayed cracking tests on automotive high-strength steel has a wedge-shaped slot with a snap-fit ​​angle α of 45°.

[0010] The aforementioned fixture for delayed cracking testing of automotive ultra-strong steel has anti-slip stripes on its outer wall or its outer wall is hexagonal.

[0011] The beneficial effects of this utility model are as follows: The overall clamping unit of this utility model has a small volume, and when the same material is immersed in acid at the same time, the clamping unit suffers less acid loss, thus reducing the error of the experimental results; the clamping unit is designed as a split type, which is convenient to assemble and disassemble, and is suitable for clamping material pieces within different preset angles (80°-140°), and the clamping force can be adjusted as needed to simulate the actual stress state of the product parts. It can be used in material verification before product development, which greatly reduces the risk of material application; wedge-shaped slots are opened on the upper and lower surfaces of the clamping block, and one set of clamping unit can clamp two material pieces at the same angle at the same time, making full use of space and improving the efficiency of cracking test; the tightening nut is tightened by tightening sleeve on the outer wall to ensure the consistency of clamping force. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings.

[0013] Figure 1 This is a schematic diagram of the overall structure of the clamp of this utility model;

[0014] Figure 2 This is a schematic diagram of the disassembled fixture structure;

[0015] Figure 3 This is a schematic diagram of the connection structure between the tightening sleeve and the tightening nut;

[0016] Figure 4 This is a schematic diagram of the clamping structure for different pre-bending angles of the sheet material.

[0017] In the diagram: 1. Fixed clamping block; 2. Moving clamping block; 3. Adjusting screw; 4. Positioning pin; 5. Tightening nut; 6. Fixing nut; 7. Wedge groove; 8. Tightening sleeve; 8-1. Sleeve body; 8-2. Compression spring; 8-3. Ball bearing; 9. Washer; 10. Material sheet. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] See Figure 1 , Figure 2 and Figure 4 This utility model discloses a fixture for delayed cracking testing of automotive high-strength steel, comprising a fixed clamping block 1, a movable clamping block 2, an adjusting screw 3, locating pins 4, and a tightening nut 5. The fixed clamping block 1 is fixed to one end of the adjusting screw 3 by a fixing nut 6. Two locating pins 4 are provided, each being a smooth shaft, with one end fixed to the fixed clamping block 1 and located on both sides of the adjusting screw 3. The other end of the locating pin 4 passes through a locating hole on the movable clamping block 2, and the two are slidably connected, with the locating pins serving as guides. The movable clamping block 2 and the adjusting screw 3 are spaced apart. The tightening nut 5 is located on the outside of the movable clamping block 2, and a washer is provided between them. The tightening nut is threadedly connected to the adjusting screw 3. The movable clamping block 2 is provided with a wedge-shaped groove 7 on the side opposite to the fixed clamping block 1, and wedge-shaped grooves are provided at the upper and lower ends respectively. The clamping angle α of the wedge-shaped groove is 45°, which is suitable for clamping material sheets with a pre-bending angle of 80°-140°. The fixed clamping block 1 has the same structure as the movable clamping block 2. The two ends of the pre-bent sheet 10 are engaged in the wedge-shaped grooves. The position of the tightening nut 5 on the adjusting screw 3 is adjusted by wrench, thereby driving the moving clamp block to slide towards the fixed clamp block until the moving clamp block clamps the sheet. Then, the tightening is stopped, and the fixture and the sheet are immersed in the acid solution for soaking. The clamp block can simultaneously clamp two sheets with the same pre-bending angle in the vertical direction, improving the test efficiency. Furthermore, by adjusting the position of the tightening nut, sheets with different preset angles can be clamped, making the operation simple.

[0020] See Figure 3 A tightening sleeve 8 is also provided outside the tightening nut 5, including a sleeve body 8-1, a compression spring 8-2, a ball bearing 8-3, and a screw 8-4. The sleeve body 8-1 is concave and fits onto the outer wall of the tightening nut 5, with the inner wall of the sleeve body smoothly connected to the outer wall of the tightening nut. A through hole is provided on the side wall of the sleeve body 8-1, the diameter of the top of the through hole being smaller than the diameter of the ball bearing 8-3. The compression spring 8-2 is disposed in the through hole, and the ball bearing 8-3 is disposed on the top of the compression spring, with the top of the ball bearing protruding from the top of the through hole and matching and contacting a spherical groove on the outer wall of the tightening nut 5. When the sleeve body rotates, the ball bearing drives the tightening nut to tighten. Rotating along the adjusting screw, the center of the ball bearing 8-3 is lower than the top of the through hole to prevent the ball bearing from slipping out of the through hole. The screw 8-4 is fixed to the bottom of the through hole to support the compression spring. The gap between the bottom center of the sleeve and the adjusting screw 3 facilitates the rotation of the sleeve, which drives the tightening nut to move axially along the adjusting screw. The tightening nut 5 is a round nut. Washers 9 are provided between the tightening nut 5 and the moving clamping block 2, and between the tightening nut 5 and the sleeve 8-1. The outer wall of the sleeve 8-1 is provided with anti-slip stripes or the outer wall of the sleeve is hexagonal to facilitate tightening. When it is necessary to clamp the material, rotate the sleeve. The ball bearings in the sleeve drive the tightening nut to rotate and move towards the fixed clamping block, thereby moving the moving clamping block to clamp the material. Select the appropriate compression spring specifications for the sleeve as needed. After the moving clamping block clamps the material, if the torque of the sleeve continues to rotate and becomes too high, the balls will dislodge from the groove on the outer wall of the tightening nut and, under the pressure of the outer wall of the tightening nut, will enter the through hole of the sleeve downwards. At this point, if the sleeve continues to rotate, it will be unable to drive the rotating nut to continue tightening. This serves as a standard for uniform preload to ensure the consistency of the material's preload.

Claims

1. A fixture for delayed cracking test of automotive ultra-high strength steel, characterized by: The clamp comprises a fixed block (1), a movable block (2), an adjusting screw (3), a positioning pin (4) and a tightening nut (5), the fixed block (1) is fixed at one end of the adjusting screw (3) through a fixing nut (6), the positioning pin (4) is provided with two ends fixed on the fixed block (1) respectively and arranged on both sides of the adjusting screw (3), the other ends of the two positioning pins (4) pass through the positioning holes on the movable block (2) and are slidably connected, the movable block (2) is slidably connected with the adjusting screw (3), the tightening nut (5) is arranged outside the movable block (2) and is threadedly connected with the adjusting screw (3), the side opposite to the fixed block (1) of the movable block (2) is provided with a wedge-shaped clamping groove (7), and the structure of the fixed block (1) is the same as that of the movable block (2).

2. The fixture for delayed cracking test of automotive ultra-high strength steel according to claim 1, characterized in that: The clamp further comprises a tightening sleeve (8) comprising a sleeve body (8-1), a compression spring (8-2), a ball (8-3) and a screw (8-4), the sleeve body (8-1) is arranged in a concave shape and is sleeved on the outer wall of the tightening nut (5), the side wall of the sleeve body (8-1) is provided with a through hole, the diameter of the top of the through hole is smaller than that of the ball (8-3), the compression spring (8-2) is arranged in the through hole, the ball (8-3) is arranged on the top of the compression spring, the top of the ball protrudes from the top of the through hole and is in matched contact with the spherical groove on the outer wall of the tightening nut (5), the ball center of the ball (8-3) is lower than the top of the through hole, the screw (8-4) is fixed at the bottom of the through hole, the bottom center of the sleeve body is gap-connected with the adjusting screw (3), the tightening nut (5) is arranged in a circular nut, and a gasket (9) is arranged between the tightening nut (5) and the movable block (2) and between the tightening nut (5) and the sleeve body (8-1).

3. The fixture for delayed cracking test of automotive ultra-high strength steel according to claim 1, characterized in that: The upper and lower ends of the movable block (2) are both provided with the wedge-shaped clamping grooves (7), and the fixed block (1) is correspondingly provided with two wedge-shaped clamping grooves.

4. The fixture for delayed cracking test of automotive ultra-high strength steel according to claim 3, characterized in that: The clamping angle α of the wedge-shaped clamping groove (7) is 45°.

5. The fixture for delayed cracking test of automotive ultra-high strength steel of claim 2, wherein: The outer wall of the sleeve body (8-1) is provided with anti-skid stripes or the outer wall of the sleeve body is hexagonal.

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