钢经过热处理后不但机械与物理性能起了根本的变化,而且体积和几何形状也随着改变。这种变形分为两种:一是体积的变化,可以叫做体变,它是组织转变的结果;一是形状的变化,可叫作挠曲,它是热应力和组织应力的产物。在热处理过程中,它们是同时产生而不可消除的两种缺陷。要想减少变形,就从以下两方面着手:(1)减少因组织转变而造成的体积差;(2)减少因工件各个截面上因热变化和组织变化不均所引起的,热应力和组织应力。减少组织转变中的体积差的有效方法,是从 After heat treatment of steel not only mechanical and physical properties have played a fundamental change, but also with the volume and geometry changes. This deformation is divided into two kinds: First, the volume change, can be called body change, it is the result of organizational changes; First, the shape change, can be called flexing, it is the product of thermal stress and tissue stress. In the heat treatment process, they are produced simultaneously and can not be eliminated two defects. To reduce distortion, proceed from the following two aspects: (1) to reduce the volume difference caused by organizational changes; (2) to reduce due to thermal cross-section changes in the workpiece and uneven tissue changes caused by thermal stress and tissue stress. The effective way to reduce the volume difference in organizational change is from