本发明涉及一种细晶热处理方法，属于热处理技术领域。本发明细晶热处理方法，包括以下步骤：a )将亚共析钢加热至AC3±10℃，第一次保温；然后继续升温至AC3+50～100℃，第二次保温；或b)将过共析钢加热至AC1±0～20℃，第一次保温；然后继续升温至AC1+50～100℃，第二次保温；a)和b)中第二次保温时间均为第一次保温时间的1/4-1/3。钢材经本发明细晶热处理方法处理后，晶粒细小而均匀，综合机械性能得到明显提高。

The invention relates to a heat treatment method of fine grains, and belongs to the technical field of heat treatment. The heat treatment method of the fine grains comprises the following steps of (a) heating hyposteel to AC3 plus or minus 10 ℃, and insulating for the first time; then continuing heating to AC3 plus or minus 50 to 100 ℃, and insulating for the second time; or (b) heating hypereutectoid steel to AC1 plus or minus 0 to 20 ℃, and insulating for the first time; then continuing heating to AC1 plus or minus 50 to 100 ℃, and insulating for the second time, wherein the insulating time for the second time is 1/4 to 1/3 of that for the first time in the steps (a) and (b). After steel is treated by adopting the heat treatment method of the fine grains, the grains are fine and uniform, and the overall mechanical properties are obviously increased.