7CrSiMnMoV钢的马氏体形态及其强韧性研究

MORPHOLOGY OF MARTENSITE IN 7CrSiMnMoV STEEL AND ITS STRENGTH-TOUGHNESS

本文用金相及电子显微分析研究了7CrSiMnMoV钢的马氏体形态及亚结构,并对不同形态的马氏体转化规律进行了分析。研究发现该钢冷却产生的马氏体有三种类型,包括晶界上优先产生的具有位错亚结构的宽大板条马氏体,晶内较细小的板条马氏体以及内部少量的孪晶马氏体片。基于上述结果,本工作试用短时等温淬火形成的下贝氏体来代替晶界马氏体,证明晶界组织形态对材料的强韧性有着很大的影响。

The morphology and substructure of martensites in 7CrSiMnMoV steel were observed under optical or electron microscope, and martensitic transformation with its morphology was also analysed. In the normally quenched steel three types of martensites are found, including the wide lath one of dislocation substructure form- ed preferentially along grain boundaries, the thinner inner laths and the twinning martensite plate in interior of grain. Therefore, an attempt was made to substitute lower bainite, formed by short-term isothermal quenching, for intergranular marten- site, it is believed that the morphology would be very influential to the strength- toughness of the steel.