The hot press forming process for automotive components can produce crash-resistant parts with high strength, minimum springback and reduced sheet thickness using martensitic transformation of sheet metal. In this study, the hot press bending (HPB) process was optimized to obtain high strength and dimensional accuracy of bent components. Heating temperature and soaking time of the blank were optimized at 900 °C and 10 min, respectively. Also, the cooling channel in the bending dies necessary to obtain full martensitic transformation of the bent part at high cycle of repetition was determined by using design of experiment and FE(finite element)-simulation. Significant factors that influence the cooling intensity were the distance between the cooling channel and the die surface, and the flow condition. The result of FE-simulation and experiments with the design based on injection molding showed that bent components with high strength and dimensional accuracy without bainite transformation can be obtained by this optimized HPB process.
展开▼
