Basis Research On Hot Stamping Technology Of High Strength Steel TRB

Environmental pollution and other practical issues determine that lightweight of the car is necessary for sustainable development of the automotive industry,BIW using TRB is one of the ways to achieve lightweight targets.Compared with the conventional blank,according to the actual collision load distribution of body in white,TRB has reasonable design sheet thickness and can reduce body quality.The combination of TRB and hot stamping process can achieve the double effect of body weight loss,and improve the strength of BIW to ensure the safety of the car.Compared with the traditional hot stamping technology,as represent from the "Control Shape" to "Control Performance",in the future,the development of hot stamping of TRB technology is feasible and important.In this paper,the 22MnB5 steel was used as the research object to study the high temperature flow stress behavior of 22MnB5 by thermal simulation method.The relationship between stress and temperature,strain rate and strain was obtained.The finite element model of TRB is established by DEFORM software.The theory of mechanics,heat transfer and phase transition dynamics related to the hot stamping of TRB were summarized.The relationship between temperature field,stress field and phase transition in the hot stamping process was analyzed.The whole process of hot stamping of TRB was simulated by DEFORM software.The variation of temperature field and stress field and the distribution of phase transition were summarized in the process of sheet transfer,blanking,forming and quenching.The influence of the two process parameters on the hot forming process of TRB was analyzed by finite element software,and the reasonable parameter range was determined.In this paper,the influence of the heat transfer coefficient between the sheet and the die and the temperature of the die on the hot forming parts of TRB with the performance gradient distribution is analyzed by finite element method.The heat transfer coefficient and the die temperature in different area are determined,and the feasibility of the hot rolling forming parts with variable gradient performance is discussed.The design of the die used in the finite element model is made.The structural design takes into account the two aspects of the profile and the sheet support design and ensures that the cooling system of the die meets the cooling requirements.And the die required for the partitioning and cooling experiment platform of blank is made,which consists of two parts: heating zone and cooling zone,the feasibility of partition cooling test is analyzed by finite element method.