The part of our factory producing 35 steel grade 10 M8 ~ M24 nut is: 镦 shape → normal fire → reaming → tapping → quenching → tempering. Since the national standard of 6H thread does not specify the amount of deformation after thread quenching and the reserved amount of galvanized layer. Therefore, when the diameter of the thread is close to the limit size, after quenching and galvanizing, the thread plug is often used to check the ride "stop" and "stop".