20钢晶粒超细化工艺研究

Study on the Super Fine Grain Technology of Steel 20

研究了快速加热循环淬火工艺细化20钢晶粒的原理,探讨20钢晶粒细化的最佳工艺参数(加热温度、加热速度、淬火次数和保温时间),实验结果表明:最佳热处理参数是890℃加热,保温18min,水淬4次;经过细化后的奥氏体晶粒平均直径比原始晶粒直径小了将近一倍;高温时奥氏体晶粒越细小,室温下的组织越细小;淬火后的硬度达到44~50HRC。

In this paper, the theory of rapid heating cycle quenching process for refining the grain size of steel 20 is studied. The optimum process parameters such as heating temperature, heating rate, quenching times and holding time are determined. The result shows the optimum parameters are heating at 890 ℃, holding 18 minutes and quenching for 4 times. The average austenitic grain size was decreased more than half of the original grain size after grain refinement process. With the decreasing of austenitic grain size at high temperature, the smaller structure can be obtained at room temperature. The hardness of Steel 20 increased to 44～50 HRC after quenching treatment.