Numerical Simulation On Cooling System Of Hot Stamping

High-strength steel plays an important role for realizing light weight of body in the automotive industry, so hot stamping process used for the forming of it has become a hot research spot. Hot stamping is such a technology, which makes full use of die to form different kinds of parts. During such process, the plasticity and ductibility of the material with high temperature decrease a lot, in contrast, its yield strength decrease. After austenitized at 900℃, high-strength steel was quenched by no less than the cooling rate with 21℃/s, which is the most favourable for the formation of martensite organization. The study provides clear requirement and proposes severe challenges for designing cooling system. Therefore, to improve the environmental protection and safety of cars, and to spread the use of high-strength steel in automobile manufacturing, the proper design for the cooling system of hot stamping moulds has great significance.Firstly, combined the knowledge of heat transfer and fluid mechanics, the model of cooling system in hot stamping was established and the design guidelines were proposed. Then, the related parameters were calculated for the design of cooling system.Secondly, the numerical simulation of temperature field for the straight-arrange cooling system was analysed by ANSYS software, and the research of temperature field distribution on the water velocity, pipeline distance and the distance between pipeline and work surface was carried out. Then, the influences of these parameters on the cooling effect were obtained, and the reasonable ranges of these parameters were gained to meet the demand of quenching. These can provide the theoretical basis to solve the heat accumulation problems in hot forming mold and give the reference in the practical application.Lastly, the cooling effects of two mixed-arrange systems were analysed by numerical simulation, such as discrete support and rib-type support. For the support type of cylindrical body, the influence of water velocity on quenching effect was discussed, then the critical flow rate was obtained, and the maximum temperature difference and the cooling rate on the steel plate surface were gained. Compared the straight-arrange with mixed-arrange cooling system, the application scopes of them were determined. It could offer a basis for designing the cooling system of hot-stamping dies.