稀土合金化高碳耐磨钢连续冷却转变曲线的建立及组织转变

Establishment of Continuous Cooling Transformation Curve and MicrostructureTransformation for Rare Earth Alloyed High Carbon Wear Resistant Steel

采用金相显微镜、场发射扫描电镜和淬火膨胀仪研究稀土合金化高碳耐磨钢不同冷却速度条件下的转变组织、相变临界点和不同冷却速度下过冷奥氏体的连续冷却转变曲线(CCT曲线)。结果表明:相变临界点为Ac_(1)为742.6℃,Ac_(3)为816.5℃,Ms为307.0℃。当冷却速度小于0.4℃/s时,显微组织为少量铁素体+珠光体;当冷却速度为0.4℃/s时,显微组织为单相伪共析珠光体;当冷却速度大于0.5℃/s时,显微组织逐渐向马氏体转变;冷却速度高于4℃/s时,钢中仅有马氏体+残余奥氏体组织。

The transformation structure and critical points of phase transformation for rare earth alloyed high carbon wear resistant steel as well as continuous cooling transformation(CCT)curve of undercooled austenite at different cooling rates are studied by metalloscope,field emission scanning electron microscopy and quenching dilatometer.The results showed that the critical points of phase transformation were Ac_(1)=742.6℃,Ac_(3)=816.5℃and Ms=307.0℃.When cooling rate is less than 0.4℃/s,the microstructure is a small amount of ferrite+pearlite;when cooling rate is 0.4℃/s,the microstructure is single-phase pseudo eutectoid pearlite;when cooling rate is greater than 0.5℃/s,the microstructure is gradually transformed to martensite;when cooling rate is greater than 4℃/s,there is only the microstructure of martensite+retained austenite in the steel.