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Why does the tensile machine always break at the jaw position during testing

2024-01-23

There are many reasons that can affect the breakage of the pliers on the steel wire tensile machine:

The phenomenon of jaw fracture of steel wire in tensile test is generally due to the small gap formed by the bite of the jaw teeth on the steel wire, which forms a fracture source. The magnitude of its influence is related to the following factors. Based on various steel wire materials to prevent wire breakage during tensile testing, our company adopts a comparison of the tooth pattern of the pliers with each steel wire material.

1. The material of the broken jaws and fixtures has a direct impact:

Fixtures made from ordinary steel and iron materials cannot hold steel wires, and it is also important to note the material of the tooth block inside the fixture.

2. The influence of notch shape:

Due to the different jaws of the tensile testing machine, the impact is significant when the notches are different and generally sharp; When the gap is at an obtuse angle, the impact is relatively small.

3. The influence of wire diameter size:

Large diameter steel wire (greater than 2mm), due to its high tensile strength and large contact area between the sample and the jaws, has a fast biting speed and is not easy to cause slip or surface notches of the sample, resulting in jaw fracture. Therefore, large diameter steel wire is not sensitive to notches.

Small diameter steel wire has a small contact area with the jaw, which is not easy to bite and can easily cause a gap at the jaw. The reaction of small diameter steel wire to the gap is greatly increased. Therefore, it can be seen that the size of the steel wire diameter adopts different shapes of pliers.

4. The influence of steel wire strength:

Steel wires with higher strength have a greater reaction to notches than those with lower strength. Generally speaking, high-strength steel wires have poor toughness and greater brittleness, and small notches can lead to their fracture; Low strength steel wires with better toughness are less prone to fracture.

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