The grades of expansion bolts are divided into 45, 50, 60, 70, and 80;
The materials are mainly divided into austenite A1, A2, and A4;
Martensite and ferrite C1, C2, C4;
Its representation method, such as A2-70;
The front and back respectively represent the bolt material and strength grade
(1) Common materials for bolt materials: Q215, Q235, 25, and 45 steel. For important or special threaded connectors, alloy steels with higher mechanical properties such as 15Cr, 20Cr, 40Cr, 15MnVB, 30CrMrSi, etc. can be selected.
(2) The allowable stress of threaded connectors is related to the load properties (static and variable loads), whether the connection is tightened, whether the pre tightening force needs to be controlled, and factors such as the material and structural dimensions of the threaded connector.