双相区轧制对铁素体/马氏体双相钢组织性能的影响

采用双相区(α+γ)轧制及双相区短时保温处理相结合的方式,制备了一种高强高韧性低碳低合金铁素体/马氏体双相钢,并采用SEM、室温拉伸试验和维氏硬度检测等手段研究了不同轧制工艺对铁素体/马氏体双相钢组织和性能的影响。结果表明:相对于普通的连续轧制工艺,等温轧制和道次之间短时保温处理相结合的工艺对铁素体/马氏体双相钢的相比例、形貌和尺寸有重要影响。等温轧制及短时保温处理的双相钢的组织明显细化,马氏体相比例增加,组织均匀性显著改善,屈服强度提升了34%,达到1229 MPa,屈强比高达0.78,断口为韧性断口特征,呈细小韧窝状,具有良好的综合力学性能。

Effect of intercritical rolling on microstructure and mechanical properties of ferrite/martensite dual-phase steel

By combination of rolling in (α+γ) dual-phase region and short-time heat preservation treatment in the dual-phase region,a high-strength high-toughness low-carbon low-alloy ferrite/martensite dual phase steel was prepared.The effect of different rolling processes on the microstructure and mechanical properties of the ferrite/martensite dual-phase steel were investigated by scanning electron microscopy (SEM),tensile test at room temperature and Vickers hardness test.The results show that,compared with the common continuous rolling process,the combination of the isothermal rolling with the short-time heat preservation treatment between passes has an important influence on the phase ratio,morphology and size of the ferrite/martensite dual phase steel.The microstructure of the dual-phase steel after isothermal rolling and short-time heat preservation treatment is obviously refined.The martensite phase ratio is increased,and the structure uniformity is significantly improved.The yield strength is increased by 34% to 1229 MPa,and the yield ratio is as high as 0.78.The fracture surface is ductile fracture type characterized by small dimples and showing good comprehensive mechanical properties.