汽车用800 MPa级冷轧低合金高强钢的研制

采用C-Si-Mn-Nb-Ti-Cr-Mo合金成分体系,全流程控制关键生产工艺参数,研发出具有良好塑性和成形性的800 MPa级冷轧低合金高强钢。结果表明,试验钢的显微组织由铁素体、马氏体和少量贝氏体组成,铁素体基体中有弥散分布的第二相粒子和碳化物沉淀相。试验钢的屈服强度在800 MPa以上,断后伸长率大于10.5%,抗拉强度和屈服强度相差小于35 MPa,扩孔率在56.5%以上,180°冷弯角度下弯曲无可见裂纹,表现出良好的成形性能。

Development of cold-rolled 800 MPa grade high strength low alloy steel for automobile

Cold-rolled 800 MPa low alloy high strength steel with good ductility and formability was developed by means of C-Si-Mn-Nb-TiCr-Mo chemical composition design and key production process parameters control.The results show that the microstructure of the tested steel is composed of ferrite,martensite and a small amount of bainite.The second phase particles and carbide precipitation phases are dispersed in the ferrite matrix.The yield strength of the tested steel is more than 800 MPa,the elongation is more than 10.5%,the difference between tensile strength and yield strength is less than 35 MPa,the hole expansion rate is more than 56.5%,and there is no visible crack on the 180°cold bending test,which showing good formability.