42nd International Deep Drawing Research Group Conference - IDDRG 2023

Recently, the automobile industry is increasing demand for hot stamping parts due to the growth of eco-friendly vehicles with the lightening and the crash safety performance. In the hot stamping process, a high-temperature heated steel sheet is simultaneously stamped and quenched to manufacture ultra-high-strength components of 1.5GPa or more. However, it takes more than 10 to 15 seconds to meet dimensional quality and mechanical properties during stamping. For this reason, it has the disadvantage of poor productivity compared to cold stamping. Moreover, the hot stamping component has a difference in cooling behavior depending on the geometry position. In particular, during deep drawing with a large deformation, the contact pressure is decreased due to the decrease in the thickness of the sidewall of components, and thus the cooling speed is significantly decreased. Therefore it can be said that the production cycle time of hot stamping components is determined according to the cooling performance of the sidewall. In this study, the groove pressing was applied to the sidewall of the die to increase the contact pressure and improve the cooling rate. Then, the cooling performance according to the groove shapes was evaluated through a hot stamping simulator, and the changes in dimensional quality and mechanical characteristics were analyzed together. In addition, the Cyclic Corrosion Test (CCT) was verified to see if there was any problem with corrosion resistance on the surface of the component where the groove pressing was applied.