High-strength medium carbon steel raw material quenched & tempered to Class9.8 mechanical property for heavy load structural fastening application.

Uniform black phosphate surface treatment improves anti-rust performance and reduces friction during installation tightening.
Integrated hex washer head eliminates separate flat washer installation, saves assembly time and prevents gasket displacement under vibration.
Standard M20 metric thread with precise rolling thread craft guarantees consistent clamping force and avoids thread slipping during torque fastening.
Widely used for mechanical frame assembly, equipment base fixing and heavy machinery structural connection under static and mild dynamic load.