Regarding the annealing and normalizing of screws: it is used for hot-worked blanks, carbon steel and alloy steel with a carbon content greater than 0.5%, to reduce the hardness and make it easier to cut, and annealing is often used; while the carbon content is less than 0.5% carbon For steel and alloy steel, in order to avoid sticking to the knife when the hardness is too low, normalizing treatment is adopted. Annealing and fire are commonly used to refine grains and uniform structure, in preparation for subsequent heat treatment. Annealing and normalizing are usually arranged after the blank is manufactured and before rough machining.
Divided into surface quenching and overall quenching. The difference is that surface quenching is widely used due to small deformation, oxidation and decarburization, high external strength, good wear resistance, good internal toughness and strong impact resistance. To improve the mechanical properties of surface quenching, heat treatment such as quenching and tempering or normalizing must be carried out as a preliminary heat treatment.
It is mainly used to eliminate the internal stress generated in blank manufacturing and machining. Parts with general precision can be arranged for an aging treatment before finishing. For parts with high special precision requirements, two or more aging treatments are arranged, and simple parts may not be subjected to aging treatment. For some precision parts with poor rigidity, in order to eliminate the internal stress generated during processing and stabilize the processing accuracy of the parts, multiple aging treatments are carried out between rough machining and semi-finishing. As for fastener shaft parts, they are placed in the straightening process for aging treatment.
Application of stainless steel screws and nuts
2023 04/14