Heat treatment deformation of workpieces - mainly caused by heat treatment stress. Factors such as the structural shape of the workpiece, the quality of raw materials, the processing state before heat treatment, the self weight of the workpiece, and improper support or clamping of the workpiece during heating and cooling in the furnace can also cause deformation.

Any heat treatment process involving heating and cooling may cause deformation of the workpiece. However, quenching deformation has the greatest impact on the quality of heat treatment. Severe quenching deformation is often difficult to correct through final precision machining, and even if the quenched workpiece can be corrected and machined, it will increase production costs. The unstable structure and stress state of the workpiece after heat treatment gradually undergo transformation and tend to stabilize during long-term storage or use at room temperature and below zero temperature. This deformation is also accompanied by deformation of the workpiece, which is called aging deformation. Although time deformation is not significant, it is also not allowed for precision parts and standard measuring tools.

The heat treatment deformation of workpieces can be divided into two forms: dimensional variation (volume deformation) and shape distortion. Dimensional deformation can be attributed to the volume change of the workpiece caused by the difference in specific volume before and after phase transformation, while shape distortion is caused by uneven plastic deformation under various complex stress combinations during the heat treatment process. These two forms of deformation rarely exist separately, but for specific workpieces and heat treatment processes, one form of deformation may prevail.