Investigation On The Hot Stamping Process And Criterion For Die Design Of High Strength Steel Automobile Parts

The development of ultra high strength steel make it possible to decrease the vehicleweight and fuel consumption while improve car safety at the same time. In order todecrease the springback, hot stamping process, which results in better formability, lowerspringback and higher performance, is becoming increasingly used in the automotiveindustry. However, product and die design, which is the key technology in hot stamping,received inadequate attention in domestic area. Thus it is in desperate need of designcriteria to instruct the product and die design in hot stamping as a direction.Investigation is made on the die design parameters based on the hot stamping processprinciple and characteristics. Design criteria of product, process and die in hot stamping,which act as the direction in the front bumper die design and manufacturing, are proposedin this paper. Specific basic problems are investigated for the preliminary establishmentof design criteria. For instance, analyses are made on the influence of die clearance on thehot stamping process and1.0~1.05t（blank thickness）is recommended as the clearance indie design; researches are made on die division principles and how to analyze the formingand cooling process effectively with finite element software in order to instruct thestructure design of die division and cooling system is also discussed. Elaboration is madeon the unique auxiliary device in hot stamping, such as the typical structure of blankholder.The requirements and rules of product and die design in hot stamping aresystematically summarized based on the research in front bumper beam die design and theanalyses on the difference in die design between hot stamping and cold stamping. Theproduct design should not only meet the crash response characteristics of invasion andenergy absorption but also the forming process capability. The potential offered by ultrahigh strength steel can only be realized to full advantage if there is planned coordination of material characteristics, part design geometry, and die process capability.For the purpose of laying foundation for the die and modular design standardization,die design methods and process are elaborated with case based on the proposed vehicleproduct and die design criteria.