The Study of the Springback Effect in the UHSS by U-bending Process

Abstract

Nowadays, the tendency by using the Ultra High Strength Steel (UHSS) in automobile industry has been increased in order to minimize the total weight of the car. The major problem by using of the UHSS in manufacture the automobile parts is springback. The objective of this research is to investigate the springback effect of the UHSS in U-bending process. In the experiment, the various forming parameters were conducted such as punch radius and blank holder force, the experimental materials in this study was JSC780Y, SPCN590R and JSC440W. According to the procedure, the experiment was conducted by specially designed of U-bending die, the U-shaped cross-sections refer to the NUMISHEET 2011, the benchmark for controlling the dimension of tool geometry. Springback angles after bending process were measured and calculated to springback factor for comparing and presenting the tendency of the springback effect.As the experimental results, the influence of forming parameters found the increasing punch radius increased the springback angle while the increasing blank holder force decreased the springback angle. The springback factor value decreased when the springback angle increased. The results are showed the tendency of springback angles, which is useful for predicting springback effect of the UHSS.