Annealing Process And Stamping Simulation Of Dual-phase Steel Tailor Rolling Blanks

As oil resources are increasingly reducing,automotive lightweight has aroused people’s concern.Lightweight of automobile has two thoughts.One is using high strength and toughness material.For example:dual-phase steel.The other is according to the force of the parts design longitudinal cross-section shape and size.For example:Tailor Rolling Blanks.Therefore,the combination of dual-phase steel and Tailor Rolled Blanks will have a very huge development potential.In order to gain the uniform and stable performance in different regions of DPS-TRB,annealing process need to research.Use ABAQUS to create stamping process simulation.It can guide the actual stamping process.The main research conclusions are as follows:1)Studied on the effect of different heating temperature on mechanical properties in batch annealing simulation experiments.According to the chemical composition and original morphology of DP590 dual-phase steel,through batch annealing can’t get the uniform and stable performance in different regions of DPS-TRB.2)Thickness(reduction rate),heating temperature,holding time and cooling rate,these factors are chose to design continuous annealing orthogonal experiments.The influence degree of the yield strength is as follows:the largest is thickness(reduction rate),followed by cooling rate,have nothing to do with the time of heat preservation.The influence degree of the tensile strength from big to small is as follows:thickness(reduction rate),heating temperature,cooling rate,holding time.3)Studied on the direct influence factors of high yield strength.The first is the high movable dislocation density in ferrite.In a certain range,with cooling rate increasing,the generated martensite increase gradually and its volume expand.Ferrite is extruded and the generated movable dislocation density increase,the plastic deformation resistance is higher,the higher the yield strength.The second is necessary second phase particles in ferrite by solid solution method.When the dislocation lines through the large size of the second phase particles,they have been hampered.So the yield strength increased.4)Studied on two heating system of continuous annealing processes:two-phase region heating and austenite region heating.In a certain range,with two-phase region heating temperature rising,phase transformation activation energy and diffusion activation energy are enhanced gradually,generated austenite cores increase gradually,austenitic phase boundary migration rate rise,austenite grow more full,the martensite after quenching is more and more big.0.6mm、0.9mm、1.2mm cold rolled dual phase steel through continuous annealing treatment in austenite region heating.Its mechanical properties meet the performance requirements of DP590 dual phase steel.Microstructure has two characteristics:First,the content of martensite increased significantly,and its distribution very uniform.Second,the chaos and no orientation form in the ferrite and martensite.5)Finite element software ABAQUS is used to establish numerical model of stamping process of DPS-TRB.True stress and true plastic strain data of different thickness dual phase steel are imported.Different regions of dual phase steel are endowed with different material behaviors.According to the form of longitudinal section of DPS-TRB,blank holder and punch are designed.The force and deformation of the plate are more uniform.