In addition to the different performances in the treatment process, the high-strength bolts with different raw materials have different retardation and fracture properties under high pressure conditions. First of all, the tensile strength of high-strength bolt raw materials has a great relationship with the quenching process. Generally, it is difficult to reach the raw material requirements of 10.9 high-strength bolts after 40-degree quenching treatment. If it is not strictly normal inspection, it can be quenched according to the product. After the surface hardness to determine the strength of its tensile strength.
Secondly, the high-strength bolts of 40Cr quenching treatment are mainly used in the bolt ball node grid. The design strength is generally 390MPa (d>=30mm) or 430MPa (d<30mm). There is no high pre-use in use. Pulling pressure, if you want to add high pre-tension, you should also pay attention to understand and guarantee its delayed fracture performance. The quality of high-strength bolt products is key and it is necessary to do exactly as required.