淬火- 非等温碳分配下淬火温度对显微组织的影响

以低碳Si- Mn钢为研究对象，在MMS- 300热力模拟实验机上，分析了在DQ&P（Direct quenching & Partitioning）工艺的非等温碳分配条件下，淬火温度对试样显微组织、残余奥氏体含量和残余奥氏体中碳含量的影响。结果表明：试样的显微组织由板条状马氏体、残余奥氏体及少量铁素体组成；在320 ℃较高的淬火温度条件下，马氏体板条边界变得不明锐且弯曲，同时，碳化物沉淀含量增加；残余奥氏体含量随淬火温度的升高先增加后减少，在240 ℃时达到最大值；残余奥氏体中碳含量随淬火温度先减少后增加。

The effect of quenching temperature on microstructure in the condition of quenching and non- isothermal carbon partitioning

This paper uses the low carbon Si- Mn steel as research object to investigate the effect of termination cooling temperature on the microstructure, volume fraction of retained austenite and carbon concentration in retained austenite in the condition of quenching and non- isothermal partitioning on the MMS- 300 thermal simulation machine. Results show that the microstructures of the samples are characterized by the typical lath martensite, retained austenite and a little ferrite. At the 320 ℃ of the highest termination cooling temperature, the lath martensite boundaries become less sharp and bent. At the same time, the content of carbide precipitation increases. The content of retained austenite increases first and then decreases with the increase of the termination cooling temperature, reaching the maximum at 240 ℃. The carbon content in retained austenite decreases first and increases with the increase of the termination cooling temperature.