Research On The Formability Of DP590 Advanced High Strength Sheet And Its Application To Auto B-pillar Part

In recent of years, a great deal of time and effort has gone into reducing vehicle weight and fuel consumption for better resource and environmental performance. The application of high strength steels in vehicle has become a trend to meet the requirement of car lightweight and reducing fuel consumption and improving crash management and other safety features. And the application of advanced high strength steels has become the developing direction of steel-using for car lightweight. Compared to traditional steels, the formability of AHSS is not good. Thus, it is very important to research the stamping formability of AHSS.In this paper, the formability of AHSS, specially for DP590 was researched. By the tensile test, some mechanical properties was obtained such as yield stress, tensile strength, strain hardening index, anisotropic index, elongation and tensile ratio. It shows that tensile ratio of DP steel is smaller, n-value is higher. DP590 has higher strength properties, larger range of plastic deformation and better formability, but poor ductility. And the formability of DP590 is poorer than that of DC04.By use of the parameters of mechanical properties obtained by tensile test, the forming limit of high strength steels was predictive studied, the forming limit diagram was set up. In this part, a classical mathematical model which is based on Swift theory was used for setting up the mathematical model, and it was applied to forming limit diagrams of the steels. The forming limit was simulated by the method of curved surface. It can suppose some data and an evaluation criterion for the study of DP590 and its application to auto B-pillar. And it also can instruct how to to draw up appropriate forming process.To establish a typical components to summarize effects of different strain paths on stamping forming. The strain path was deeply analyzed, and effect of different materials and technology conditions on strain path and state of strain. By adjusting the process parameters to optimize the strain path to make the best of material plastic.Making use of previous conclusions and mechanical properties data, hardening curve, FLC etc,. to be applied in Dynaform to study the practical application of DP590. In this paper, the stamping forming process was researched by numerical simulation. And it was proposed that the structural style of drawbead was expanded form and the dimension of longitudinal section was varying, and to make better of lubricating condition between blank and punch, which can improve the forming quality of auto B pillar part at most.