One: heat treatment in the machining process of parts
The heat treatment in the machining process of parts can generally be divided into two types: preliminary heat treatment and final heat treatment. Preparatory heat treatment: Its purpose is to improve mechanical properties and eliminate internal stress in order to prepare for final heat treatment, generally including annealing, normalizing, quenching and tempering and aging treatment. Preliminary heat treatment is carried out, usually after rough machining. Final heat treatment: its purpose is to improve the hardness and wear resistance of parts, including quenching, carburizing, nitriding and other processes, generally after semi-finishing and before finishing.
Two: the precision of machining
The accuracy of machining is mainly reflected in the following aspects, which are dimensional accuracy, geometric shape accuracy and mutual position accuracy. The geometric shape accuracy includes roundness, straightness and flatness, etc., and the mutual position accuracy includes parallelism, verticality, etc. degree and coaxiality.