轧辊用新型高速钢特征温度下碳化物的析出动力学

Precipitation kinetics of the carbides in a new high speed steel for roller at characteristic temperatures

采用示差扫描量热仪(DSC)测量了轧辊用新型高速钢材料不同类型碳化物的析出温度,并采用场发射扫描电镜(FESEM)观察其典型形貌和测定其相结构。在各特征温度下,分别对轧辊用新型高速钢保温15、20、25和30 min后快冷,采用金相统计软件对碳化物的体积分数进行了统计。结果表明:轧辊用高速钢在1300℃的温度快冷后,保温25 min时MC相的体积分数有最大值;1220℃快冷后MC和M2C相的体积分数均在保温20 min时有最大值;1150℃快冷后MC的体积分数一直增加,M2C的体积分数在保温20 min时有最大值,25 min时有最小值,而M6C的体积分数先增加后减少,保温20 min时有最大值。

The precipitation temperatures of different carbides in a new high speed steel for roller were determined by differential scanning calorimetry （DSC） , while the morphology of the carboides and the phase structure of the steel were observed by field emission scanning electron microscopy. The volume fraction of carbides was statistically analyzed by software of image-pro plus for the steel after being held for 15 rain, 20 rain, 25 min and 30 rain at characteristic temperatures and then cooled. The results show that when the specimen is held for 25 min at 1300 ℃ and cooled quickly, the volume fraction of MC is the largest. When it is quickly cooled at 1220 ℃ , the volume fractions of MC and MEC are the largest after being held for 20 min. When it is quickly cooled at 1150 ℃ , the volume fraction of MC increases continuously with increasing holding time, the volume fraction of M2C is the largest after being held for 20 min and is the smallest after being held for 25 min, while the volume fraction of M6C increases at first, then decreases and reaches the largest after being held for 20 min.