Research On Optimization Of Process Parameters For Hot Stamping Of High-Strength Steel Tailor-Welded Blanks Based On Numerical Simulation

In order to reduce the weight of the car body and maintain the strength of the car body,high-strength steel sheet forming structural parts are widely used in car body manufacturing.Compared with aluminum alloy and other materials,high-strength steel has the characteristics of high material strength and excellent performance.At the same time,in order to meet the different performance requirements of different positions of the body,laser tailored blanks are increasingly used in the processing and manufacturing of body parts such as body panels,overall skeletons,door rings and automotive B-pillars.High-strength steel laser tailor-welded blanks are generally stamped and formed by hot forming.By using heterogeneous high-strength steel plates to synthesize tailor-welded blanks by welding technology,the performance requirements of different positions of auto parts are realized,and the body weight can be reduced,energy saving and emission reduction.However,due to the differences in the mechanical properties of the material itself,the high-strength steel laser tailored blanks will produce springback,wrinkling,cracking and weld offset during hot forming.Therefore,in order to improve the forming quality of the formed parts,this paper aims at Tailored welded blanks formed by laser welding of Usibor1500 P and Ductibor500 high-strength steels,using the finite element numerical simulation method,studied the effect of process parameters on the hot stamping effect of high-strength steel laser tailor-welded blanks,as follows:(1)Aiming at the high-temperature rheological behavior of high-strength steels Usibor1500 P and Ductibor500,the thermophysical property test data of the related materials were obtained through isothermal uniaxial tensile tests,and the stress-strain curves under different conditions were analyzed by taking the deformation temperature and strain rate as the changing conditions.Katsuro Inoue constitutive models of high-strength steels Usibor1500 P and Ductibor500 at high temperature were established respectively,and the prediction results of the constitutive models were good.(2)The three-dimensional modeling software Solid Works is used to complete the solid modeling of the box-shaped stamping parts,and ABAQUS is used to carry out the numerical simulation calculation of the hot-stamping of the box-shaped parts.The influence of the selected five main process parameters on the hot forming effect of high-strength steel laser tailored blank box-shaped parts was analyzed.The five process parameters are:the initial forming temperature of the sheet,the stamping speed,the blank holder force,the initial temperature of the mold,and the friction coefficient.(3)In order to obtain the minimum internal stress of the box-shaped part after hot stamping as the goal,the optimal design method of orthogonal test was used to obtain the best combination of process parameters:the initial forming temperature of the sheet was900℃ and the stamping speed is 2500mm/s.The blank holder force is 12 k N.The initial temperature of the mold is 100℃,and the friction coefficient is 0.1.The formed part with the minimum internal stress under the condition of no fracture after optimization is obtained,and the minimum internal stress of the formed part is 326 MPa.Its equivalent stress value is the minimum value.The finite element numerical simulation results before and after optimization are compared to verify that the optimized results by this method are reasonable and effective.