First of all, have a great relationship with the tensil […]
First of all, have a great relationship with the tensile strength of quenching process of high strength bolts of raw materials, raw materials require 40 degrees after hardening treatment is difficult to achieve high strength bolt 10.9, if not the usual strict inspection, according to the product surface quenching hardness to determine the tensile strength of the quality. Besides the different properties in the process, the delay and fracture performances of different high strength bolts under high pressure are also different.
Secondly, 40Cr hardened high strength bolts as raw material is mainly used in the grid structure with bolt sphere joints, design strength is generally 390MPa (d>=30mm) or 430MPa (d<30mm), high pre tension and pressure are not used, if you want to add a high pretension, but also pay attention to understand and ensure its delayed fracture performance. In order to produce a qualified good high strength bolt product, it is best to do it strictly according to the requirements.