Material selection requirements for steel structure bolts

2023-09-18 16:49:27

In addition to the different properties in the treatment process, the delay and fracture properties of steel structure bolts with different raw materials are also different under high pressure. First of all, the tensile strength of raw materials of steel structure bolts has a great relationship with its quenching process. Generally, it is difficult to reach the raw material requirements of 10.9 high strength bolts after 40 degrees quenching. If it is not strict in ordinary inspection, the tensile strength can be judged according to the surface hardness of the product after quenching.

Secondly, the high strength bolt treated by 40Cr quenching is mainly used in the bolt ball joint grid, the design strength is generally 390MPa(d>=30mm) or 430MPa(d<30mm), there is no high pretension pressure in use, if you want to add high pretension, but also pay attention to understand and ensure its delayed fracture performance. High strength bolt product quality is the key, strictly in accordance with the requirements to do is necessary.