利用差分膨胀仪测定的热膨胀曲线,对高Cr铁素体耐热钢不同冷却速度下的马氏体相变进行了研究。测定马氏体相变的动力学行为并对其微观组织进行分析。结果表明,冷却速度越高,马氏体转变的起始温度和终止温度越低。当马氏体体积分数小于40%时,转变速率达到峰值。室温组织为板条马氏体+δ-铁素体,硬度值随冷速升高而升高。 The thermal expansion curves measured by the differential dilatometer were used to study the martensitic transformation under different cooling rates of high Cr ferritic heat-resistant steels. The kinetic behavior of martensitic transformation was determined and its microstructure was analyzed. The results show that the higher the cooling rate, the lower the starting temperature and the ending temperature of the martensitic transformation. When the volume fraction of martensite is less than 40%, the transformation rate reaches the peak value. At room temperature, lath martensite + δ-ferrite was formed, and the hardness increased with the increase of cooling rate.