High-strength bolts are divided into torsional shear bolts and large hexagonal bolts, which are different from ordinary bolts (hexagonal bolts, double head bolts, anchor bolts) because they are made of low-carbon alloy steel or medium-carbon steel and heat-treated. Well, the following is mainly a summary for you from four points.
1. What are the forms of bolt failure?
1 the bolt rod is sheared; 2 the hole wall is broken by extrusion; 3 the plate is broken; 4 the end of the plate is sheared; 5 the screw is broken by bending.
two。. What are the fastening requirements of bolts?
Fastening of ordinary bolts: the fastening sequence of bolts should start from the middle and symmetrically to both sides. The fastening construction of the bolt is based on the operator's feel and the shape control of the connecting joint, and double tightening should be adopted for the large joint, that is, twice fastening method to ensure that each bolt in the joint can be subjected to uniform force.

The initial, re-and final screwing of high-strength bolted connection pairs should be carried out in the direction of less restraint in the part of the joint with greater stiffness and the order of the center of the bolt group around; the joint of high-strength bolt and welding should be fastened first and then welded in the construction order.