油淬工件淬火畸变特点的成因

Causes of Quenching Distortion Characteristics of Oil-Quenched Work Pieces

与高压气淬或者低温盐浴淬火相比,油淬工件的淬火畸变特点是:畸变数据零乱而没有规律;最大畸变程度通常也更大。出于对淬火油冷却特性曲线的错误认识而演变出来的工件表面温度与表面热流密度之间的一一对应关系,不能解释这种特点的成因。试验观测证明,表面温度与表面热流密度之间存在的是所处条件下的非一一对应关系。这种非一一对应关系是由蒸汽膜内气体的流动规律和冷却的中间阶段特性所引起的。应用这种非一一对应关系,既能解释淬火畸变程度更大的原因,也能解释畸变数据无规律的成因。

As compared with high-pressure gas quenching and low-temperature salt-bath quenching,the quenching distortion of oil-quenched work pieces features in irregularity and greater distortion.The one-to-one correspondence between the work piece surface temperature and surface heat flux density,based upon the wrong understanding of the temperature-cooling rate curve of quenching oil,cannot explain the cause of such feature.Tests indicate conditional non-one-to-one correspondence between surface temperature and surface heat flux density,which is resulted from the gas flow rules inside of steam blanket and the characteristics of the intermediate stage of quenching.Such non-one-to-one correspondence can explain greater quenching distortion and irregular distortion data.Only quenched by immersing work pieces into an evaporating liquid then has this king of distortion characteristics.