【摘要】 本研究选用国产新材料55SiMnVB 钢,采用直接高温淬火复相热处理和控制冷却复相热处理两种工艺,获得不同比例的马氏体和下贝氏体复合组织。分析了随下贝氏体量的变化、材料的静拉伸性能、冲击韧性的变化规律,并探讨了性能变化的微观机理。其结果表明,复合组织比单相回火马氏体组织或下贝氏体具有较佳的强度、塑性和韧性配合,因而可根据材料在实际服役条件下对强韧性的不同要求,确定获得最佳下贝氏体含量的复相热处理工艺。更多还原

【Abstract】 In this study,a new type of China-made 55SiMnVB steel was se- lected.The direct isothermal annealing heterogeneous heat treatment technique and the controlled cooling heterogeneous heat treatment te- chnique were used,by which textures containing various proportiona- lities of martenite and sub martenite were obtained.Law-governed change in static ductility and in impact toughness of the material in response to content variation of submartenite was investigated with additional attention to the microscopic processes involved.It is shown that complex textures are of a combined performance of batter stren- gth,toughness and plasticity,in comparison with martenite or submar- tenite textures obtained by homogeneous tempering.This suggests that a particular process of heterogeneous heat treatment may be determi- ned to obtain the best content of submartenite in order to meet a parti- cular requirement for toughness of the material in its actual service.更多还原