【作者】 王鹏丽；

【导师】 刘东雨；

【作者基本信息】 华北电力大学（北京） ， 材料学， 2010， 硕士

【摘要】 本文对长寿命贝／马复相钢进行了实验研究。采用等温处理的方法确定了不同奥氏体化温度时Nb微合金化贝／马复相钢的Bu和BL转变开始温度；通过试验方法的调节实现了HF-PJ-1400型相变仪的快速冷却,最终测出试验钢的CCT曲线,并结合金相法对冷却速度与显微组织的关系进行了分析；通过奥氏体化后冷却方式的变化避开冷却过程中的铁素体转变,结合快速加热三次循环相变细化晶粒获得了合适的显微组织；最终确定Nb微合金化贝／马复相钢是具有良好强韧性和良好超高周疲劳性能的试验钢。最后,对试验钢在利用高温回火细化晶粒过程中表现出的混晶现象进行了研究,发现Nb微合金化无碳化物贝／马复相钢具有典型的晶界遗传性。更多还原

【Abstract】 In this paper, the long-life bainite/martensite multiphase steel was studied. Isothermal heat treatment used to determine the transformation start temperature of BU and BL in different austenitizing temperatures. Super rapid cooling was achieved by the regulatory implementation of the phase transformation instrument, and the CCT curves of steel was measured. The effect of different cooling rate on microstructure was analyzed combined with the metallographic examination method, and the heat treatment process parameters was designed. By stepped cooling after austenitizing to avoid ferrite transformation, combined with rapid heating cycle of phase-transformation (three times) to obtain a suitable grain refined microstructure, the resulet of very high cycle fatigue testing show that Nb micro-alloying B/M multiphase steel has great strength and toughness properties. The mixed grain phenomenon after normal quenching of the high temperature quenching and high temperature tempering Nb micro-alloying carbide-free bainite/martensite (CFB/M) multiphase steel specimen was studied, and it proved that the steel has typical grain boundary inheritance.更多还原