Research On Hot Bending And Forming Process Of B Cross-section Tubes For High Strength Steels

The theory of auto lightweight has been developed gradually and applied widely and the application of pipe parts made of HSS(high strength steel)in automobile field is increasing gradually.The traditional cold bending and forming force of HSS is large and the quality is poor and the researches on hot forming process are just about circular and rectangular tubes.Therefore,it’s necessary to develop a new kind of hot bending and forming process for B cross-section tubes made of HSS.During the induction heating process of special section tubes,the difference between cross-section shapes leads to different between induction coils and induction heating effects.Hot bending process at different temperature will results in different tissue phase transition and different microstructure properties.So it’s necessary to do in-depth research on hot bending process of B cross-section tubes for HSS.The structure improvement and weight reduction are important for B cross-section anti-collision beam which is one of the most important parts in automobile.Combining structural advantages of B cross-section tube in collision with the weight advantages brought by the hot forming process,a new production technology of anti-collision beam has been presented to bend and form B cross-section anti-collision beam of high-strength steel to satisfy the collision safety requirement.According to the analysis of stress-strain tensile curve in high temperature,the B1500 HS material constitutive modification model has been obtained by introducing temperature compensation factor;Based on the theory of narrow plate bending,it has been acquired about the stress and strain state in different planes by analyzing the force condition of B cross-section tubes for high strength steel during bending process;The mathematical model of eddy current under the condition of electromagnetic induction heating has been proposed by analyzing the theoretical formula of magnetic field distribution in space;Based on the Flow Displacement Effect of the magnetizer,it has been solved about the Proximity Effect between adjacent conducting wires.It has been established about the finite element model of electromagnetic induction heating about B cross-section tubes for high-strength steels.Also,it has been obtained the reasonable parameters which satisfy the heating requirement by using ANSYS Maxwell software for simulation.In view of the uneven distribution of induction heating temperature,the heating simulations have been carried out and the suitable parameters of induction coil have been optimized.It has been established about the finite element model about B cross-section tubes for high-strength steels to simulate the hot bending and forming process by using ABAQUS/Explicit module,and the reasonable technological parameters has been obtained.The hot bending and forming test of B cross-section tubes for high-strength steel has been completed by setting up the experiment devices and determining the experiment scheme.It has been verified about the accuracy of theoretical analysis through the detection of full size and fixed section deviation.According to numerical comparison of bending radius,tensile strength and surface hardness,it has validate the accuracy of finite element simulation model of induction heating and hot bending forming.