Study On Parameters And Methods Of Hot Stamping Process

Safety,energy saving,environmental protection is the direction of the development of modern vehicles,which is the main way to overcome the high energy consumption and heavy pollution in our country and industrial upgrade to "made in China 2025".Recently,the ultra-high strength hot stamping parts were widely used in automobile,which is significantly improving the safety performance and reducing the fuel consumption of the vehicle,and it has effectively promoted the development of automobile manufacturing industry towards the direction of safety,energy conservation and environmental protection.The forming principle of ultra high strength hot stamping parts is to heat the special ultra-high strength steel plate to a certain temperature and preservation for a certain period of time to ensure full austenite,then rapid forming and quenching in the die and punch,so that the hot stamping parts are completely martensiting and achieving the purpose of ultra-high strength.However,there are many defects in the hot stamping forming technology of the ultra-high strength steel plate at present.In the forming process of hot stamping parts,the different mechanical properties are obtained due to the different local cooling rate.The current hot stamping technology can't meet the technical conditions of the designed processing condition.Therefore,it is of great significance to study the process parameters and methods of hot stamping.Through the analysis of the hot stamping process of B-pillar,found that the cooling rate of some complicated part of B-pillar is slow and failure to completely transform to martensite which is seriously affects its mechanical properties.Through the analysis,two kinds of optimization of the forming process were carried out.The cooling rate of hot stamping is studied by two kinds of optimization:reducing the distance between the local cooling pipe and the mold surface to improve the cooling rate of the local mold and optimization of die surface to reduce the gap between plate and die.Strain rate has a great influence on the yield strength of the materialL With the improvement of stamping equipment,the stamping speed of the die has a great select range,and the strain rate is different under different die pressing speed.Thus the different strain rate affects the flow of sheet during hot forming process.In this paper,under the condition of considering strain rate,The typical hot stamping U-shaped member is simulated under different conditions punching speed.Through the analysis of different results,the stamping speed of hot stamping process parameters is studied and initially identified the best punching speed range.The hot stamping process of medium thick and high strength steel plate was studied.Through the numerical simulations of the different thickness of the thick ultra high strength U-shaped parts,finding that with the sheet thickness increasing,the current hot stamping process is difficult to meet the processing conditions on the thickness of ultra-high strength steel and hot stamping part due to uneven quenching temperature and has a bad strength.Thus,A new type of hot stamping process is proposed,and through the numerical simulation,the feasibility of the scheme is verified,which provides a reference for the actual production.