Key Factors Numerical Analysis Of Ultra-high-strength Boron Steel Hot Stamping

One of the most important objectives of scientific research is to develop the societyenvironmentally friendly. Many efforts are being made in every engineering field. Amongthem, research for automotive lightweight has made a contribution to protect human survivalenvironment. Under this background, the hot stamping technology emerges as required. Hotstamping technology of ultra high strength steel are formed at high temperature and thenquenched into the hot stamping parts with a high strength per weight. Hot stamping parts arenot only weight-lower than traditional cold stampings, and its strength and hardness aremuch higher than cold stampings. With Automobile collision safety requirements increasingin the countries all over the world, the hot stamping are increasingly broadening applicationprospects.However, considering that the hot stamping process involves heat transfer and phasechange, its complexity is far greater than the traditional stamping process, needing moreboundary conditions into consideration. Many process parameters have important influenceon the results of hot stamping, we used*MAT₁06material model provided by LS-DYNAto built B-pillar hot stamping process FE thermal-mechanical coupling analysis in this paper.Firstly, we used LS-DYNA to set up B-pillar hot stamping thermal-mechanical couplingmodel, and compared the results with Numisheet2008Benchmark03experimental results,verifying the reliability of the finite element analysis. Secondly, we used thethermal-mechanical coupled finite element model to study the influence of different processparameters on the hot stamping process. Main process parameters for the research are asfollowed:The blank holder gap between the die and blank affects the sheet metal flange edge heattransfer, and then affects the stamping formability; the initial temperature of sheet and thematerial liquidity are highly affected by the temperature, and the different initial temperature had a greater influence on the formability of sheet metal; the coefficient of frictioninfluences the friction condition between blank and die and has a significant influence on thethinning rate of the product; both the mold contact gap and the initial temperature haveinfluence on heat transfer in the punching and quenching process, the stamping speed haveimportant effects on plastic deformation when sheet metal are forming; the pressurequenching time have important effects on parts’ strength performance after quenching.Through finite element simulation results, we optimized the design of hot stamping process.Finally, we used*MAT₂44material model to built thermal-mechanical-phase coupled FEmodel, analyzed microstructure of product changing situation and got the distribution ofmartensites after quenching.The research significance of this paper is get all the influence laws of process parameterson the hot stamping formability through thermal-mechanical coupling simulation under thecondition of different parameters. Based the results, we can effectively save the test mould inactual industrial production debugging time, and at the same time provide certain referencefor optimizing the hot stamping process.