1. Prepare for heat treatment. The purpose of preheat treatment is to improve the cutting performance of the trend, eliminate the residual stress in the blank manufacturing era of CNC lathe processing, and improve the structure. The process position is mostly before mechanical processing, and is often used for annealing, normalizing, etc
2. Heat treatment to eliminate residual stress. Because the internal stress generated during the manufacturing and machining of the blank will cause deformation of the workpiece and affect the processing quality, it is necessary to arrange residual heat treatment. The heat treatment of residual stress should be arranged before finishing after rough machining.
For parts with low precision requirements, artificial aging and annealing are usually arranged to eliminate residual stress before the blank enters the machining workshop. For complex castings with high precision requirements, two aging treatments are usually arranged in the machining process: casting-rough machining-aging-semi-finishing-aging-finishing. For high-precision parts, such as precision steel wires, precision spindles, etc. It is necessary to arrange multiple heat treatments to eliminate residual stress, or even cold treatments to stabilize the size.
3. Final heat treatment. The purpose of final heat treatment is to improve the strength, surface hardness and wear resistance of the parts, and is usually arranged before the finishing process (grinding). Commonly used are quenching, carburizing, nitriding, and carbonitriding.