Research And Optimization Of Process Parameters For Ultrahigh-strength Steel Hot Stamping Groove Parts

With the worsening of the global environment, people pay more and more attention to the environmental issues. Automobile exhaust pollution is one of the source of environmental pollution, how to reduce the exhaust pollution become the direction of the automobile industry development.Lightweight of Automobile is one of the way of energy saving and emission reduction, high strength steel plate which has the advantages of high strength, high hardness, stronger impact resistance etc, Which become more and more widely used in lightweight automobile design, Coupled with hot forming technology, energy conservation and emissions reduction, safe and reliable car manufacturing can be realized. In this paper, by the mean of a type of hot stamping mould for groove parts with the curvature of bottom that autonomous develop, Study and optimize the process parameters, using the new technology of forming and heat treatment quenching simultaneously, eventually get the ultra high strength parts and tensile strength up to 1500 Mpa.First, develop the base performance research on BR1500 HS plate, compare of the different mechanical properties and microstructure of raw material and water quenching. Then found the tensile strength of it can reach about 1480 Mpa after quenching by mould,which proved that the hot stamping groove parts mould has good cooling effect.Then develop the different process parameters affect quenching performance of hot stamping mould for groove parts with the curvature of bottom, which based on the stamping process of groove parts with the curvature of bottom on hydraulic press,then analysis indicate that the heating temperature is 950 ℃, the heating time is 4 min- 6 min, transfer time is below 12 s, the water time for more than 20 s and then the tensile strength of parts reached maximum value, Actually the tensile strength of the parts are under 1400 Mpa, due to hydraulic press pressing speed too slow, which can not reach the ideal quenching effect.Through summarizing and optimization of experimental parameters on hydraulic press, change the stamping speed, then finished the stamping process in a mechanical press, and designs the three factors, four levels orthogonal Experiment, which found that the greatest influence of the quenching effect of the product(strength, hardness) is the heating temperature, followed by the heating time, finally, the moving time. Actually confirm the optimal process parameters of groove parts with the curvature of bottom as follows: heating temperature(900℃), the heating time(5min), movement time(12s), the tensile strength up to 1500 Mpa.and put forward die mold has been water is good for heat dissipation and improve the work efficiency at the premise of die life is not affected, which provides some important reference for the hot stamping of actual production.