Investigating the Edge Forming Performance of DP600 and FV 607

Abstract

This paper scrutinises the effect of varying test parameters on two grades of advanced high strength steels (AHSSs) prepared with abrasive water jet (AWJ) machining during hole expansion test (HET). The main objective was to understand the effect of the forming speed and the bottom die geometry on the hole edge forming performance of DP600 and FV 607 AHSSs. The results showed an optimum forming speed exists between 1 and 1.6mm/s and the FV 607 displayed better hole-expansion performance at 2mm/s. This was explained by correlation between the hole expansion ratio (HER) and the flange height. The results showed that the geometry of the bottom die have an influence on the hole-edge forming capability. The sheet thinning tendency was observed more in the bulge die, and particularly at speeds above 1 mm/s which was argued by requirement for larger HER values for more excessive thinning to account for an enhanced deformation. The FV 607 grade exhibited more thinning under all test conditions.