Abstract:
In sheet forming process by using the ultra High Strength Steel (UHSS) in manufacture the automotive parts. The major problem is springback phenomenon after forming process because the elastic recovery in elastic region of material. The objective of this research is to investigate the springback phenomena when using the Ultra high strength steel in U-bending process. The experiment, changing of forming parameter will be conducted such as punch radius and blank holder force, the experimental materials in this study are JSC 780Y, SPCN 590R, JSC 440W and SPCE. According to the procedure, the experiment is conducted by specially designed of U-bending die, the U-shaped cross-sections presented in NUMISHEET 2011 that benchmark controlled the dimensions of tool geometry. Springback angles after bending process are measured and calculated to springback factor.
Due to the experimental results, the role of strength of material shown that the springback angle will increase as the material which has higher yield strength. In this case JSC 780Y was the highest yield strength and the lowest was SPCE. The changing of forming parameter was found that increasing blank holder force and decreasing radius of punch will decrease the springback angle. The springback factor value of the calculation will decrease when the springback angle increase. The results showed the difference of springback angles in each materials, which is useful for predicting springback effect of the Ultra high strength steel.