600MPa级冷轧双相钢组织对其性能的影响

采用金相显微镜和透射电镜观察了三个600MPa级冷轧双相钢的组织特征并分析了组织与性能的关系。试样组织均由铁素体和马氏体岛组成。1#、2#、3#试样的马氏体岛体积百分比分别为:13.87%、10.48%、6.49%,对应的抗拉强度分别为723MPa、654MPa、594MPa,表明随着马氏体体积百分比增加双相钢的抗拉强度逐渐上升。2#试样中发生碳化物分解的岛数量最多,屈服强度最低,推测马氏体分解,产生体积收缩,铁素体中位错发生恢复和松弛,是降低屈服强度的重要原因。

Effect of Microstructure on Mechanical Properties of Cold-Rolled Dual Phase Steel 600MPa Grade

The microstructures of three cold-rolled dual-phase steels were observed by optical microscope and transmission electron microscope,and the relations between microstructure and properties were analyzed.The microstructures are composed of ferrites and martensite islands.For the three samples marked No 1,No2,No.3,the martensite contents stand at 13.87%,10.48% and 6.49% respectively,and the corresponding tensile strengths are 723 MPa,654 MPa and 594 MPa,from which it has been found out that with the increase of martensite content,the intensity of dual phase steel increases gradually.For No.2 sample,the number of martensite islands with carbide decomposition is the largest and the yield strength is the lowest,from which it can be inferred that martensite decomposition leading to volume contraction and recovering of dislocation in ferrite are an important factor resulting in the descending of yield strength.