套筒和环形类零件在淬火后很容易变形,由于加热冷却关系,组织晶粒发生转变,致使内孔尺寸涨大,超过允许要求而报废。也有因车削不慎,将内孔车大,以致报废。为补救这种废品,用低于相变温度的缩孔处理,能解决这些问题。我厂对低于相变温度的缩孔处理,进行了长期摸索,并应用于生产,取得一定的效果。现介绍于下。一、缩孔工艺(1)将淬火涨大的套筒或环形零件进行一次正火或退火,使组织晶粒恢复原状,然后进行缩孔。未淬火 Sleeve and ring type parts are easily deformed after quenching, due to the relationship between heating and cooling, the transformation of the crystal grains, resulting in the size of the hole up, exceeding the allowable requirements and scrapped. Also because of turning accidentally, the hole car, so scrapped. In order to remedy this waste, these problems can be solved by shrinkage treatment below the phase transition temperature. I plant less than the phase transition temperature shrinkage treatment, conducted a long-term exploration, and applied to the production, and achieved certain results. Now introduced in the next. First, the shrinkage process (1) will be quenched up the sleeve or ring parts for a normalizing or annealing, to restore the original crystal grain, and then shrinkage. Not quenched