Experimental and Numerical Studies on Formability of Tailor Welded Blanks of High Strength Steel

摘要

Tailor Welded Blanks of high strength steels offer cost effectiveness by weight and parts reduction while maintaining structural integrity and crash performance. However, the potential offered by these steels can only be realized by design engineers if there is proper coordination of material properties, part geometry and process capability. The present study deals with the experimental characterization of tensile properties of parent sheets of high strength steel JSC590RN and their tailor welded blanks with thickness 1.4mm and 1.8mm. Limiting dome height tests were performed using a 100ton hydraulic press on the parent sheets and the tailored blanks to assess formability of the individual parent sheets and the given thickness combination. The increase in strength of these steels lowers the strain hardening exponent which in turn decreases the stretchability of the sheets and results in higher localized thinning. The results obtained by experiments were compared with that of the results predicted by finite element simulations using ABAQUS with incorporation of the weld zone properties. The incorporation of the weld zone properties in the simulations improved the results significantly. The predicted forming limit diagrams of the parent blanks are also plotted. It is observed that the formability of tailor welded blanks are reduced when compared with that of the parent sheets.