【摘要】 采用光学显微镜观察了在工业双辊薄带连铸机上制备的M2高速钢铸带中的碳化物,利用二次枝晶间距计算了铸带的凝固速率;并用扫描电镜和透射电镜研究了高温热处理后铸带中亚稳相M2C碳化物的演变情况。结果表明:双辊薄带连铸高速钢工业铸带的凝固速率为1.7×103K.s-1,比实验室铸带的5.4×102K.s-1高一个数量级,远远高于工业铸锭的2×10-1K.s-1;双辊薄带连铸工艺可以细化高速钢铸带中的共晶碳化物,并获得较多的亚稳相M2C碳化物,在高温热处理过程中M2C碳化物与部分奥氏体反应生成稳定相M6C和MC碳化物,使碳化物分布更加均匀弥散。更多还原

【Abstract】 The carbides in M2 high speed steel cast-strip produced by industrial twin-roll castor was studied by means of optical microscopy.The cooling rate of M2 industrial cast-strip was calculated according to the secondary dendrites space.The evolution of metastable phase M2C carbides in M2 cast-strip after heat-treatment was investigated by means of SEM and TEM.The results showed that the cooling rate in industrial twin-roll casting was 1.7×103 K·s-1,faster than that in laboratorial twin-roll casting(5.4×102 K·s-1) and in industrial casting(2×10-1 K·s-1).The twin-roll strip casting technology could refine the eutectic carbides in cast-strip and more metastable phase of M2C carbides could be obtained by this technology.The carbides in M2 cast-strip could be refined and homogenized by the decomposing of metastable phase M2C carbides during heat-treatment.更多还原