【摘要】 设计了两种低成本的铁素体/贝氏体双相钢,通过光学显微镜、扫描电镜和拉伸试验机研究了不同Si含量对试验钢组织与性能的影响,研究了试验钢在扩孔过程中的裂纹形成及扩展行为。结果表明,通过合理控轧控冷技术,能够获得780 MPa以上抗拉强度,伸长率大于17%,综合性能良好的试验钢;随着Si含量的增加,试验钢的屈服强度和抗拉强度显著提高,但是伸长率和扩孔性能有所下降;本试验钢的裂纹扩展机制为微孔聚集模式。更多还原

【Abstract】 Two kinds of low-cost ferrite / bainite( F / B) dual-phase steels were designed. The effect of different Si content on microstructure and mechanical properties of the ferrite / bainite dual-phase steel was investigated by using optical microcopy( OM),scanning electron microcopy( SEM) and tensile testing,moreover the crack propagation of the tested steel was also investigated. The results show that the tested steel has good comprehensive performance( tensile strength≥780 MPa,elongation≥17%) by controlled parameters of TMCP. With the increase of Si content,both yield strength and tensile strength of the tested steels increase obviously,but elongation and reaming property decrease. The crack of ferrite / bainite dual-phase steels formed by the mode of microvoid coalescence in this experiment.更多还原