Research On Hot Stamping Process Of BR1500HS And Its Application

High strength steel hot forming technology can solve the problem of reducingweight ofvehicles and improving crash safety at the same time,which used to Vehicleweight reduction is an important way to achieve the purpose of energy saving andemission reduction.But at present domestic study of hot stamping technology in itsinfancy,espcially for hot forming complex parts, both theoretical research and practicalproduction are in urgent need of explration in system. In this thesis,hot forming processimprovement of BR1500HS high strength steel、the fow stress constituve equation andits application of a motor part in practice are studied through phydics experiments、mechanics analysis and numerical simulations. Research achievements have a certainsignificance for the future hot stamping production.Mainly includes the followingseveral aspects:①For BR1500HS ultra-high strength steel,the basic process parametersimprovement experiments were conducted to determine the influence of heatingtemperature, hot hold time and surface high temperature oxidation coating, onmechanical properties of the quenched material.②In order to build the constitutive equations of BR1500HS, some isothermaluniaxial tensile tests are performed at600～800℃with strain rate0.01s1,0.1s1,0.1s1, by Gleeble1500D thermo-mechanical simulator, and the true stress-strain curves attherelative conditions are gained. The modified Arrhenius model, which is a hyperbolicsine function including the deformation activation energy and deformation temperature,is used to describe the hot deformation activation character of austenitemicrostructure ofboron steel. The experimental results show that,the flow stress rises with the decrease ofthe deformation temperature and the flow stress rises by increasing of the strain rate.The results show that the computational data using the constitutive relationships areconsistent with the experimental data.③On the basis of the thermal simulation high temperature drawing test, import thedata obtained from test into Dynaform finite element analysis software, to establishBR1500HS ultra-high-strength steel material model and thermal coupling simulationmodel, with numerical simulation to the front pillar reinforcement hot stamping formingprocess, through continuous optimization of simulation analysis, research blank holderforce, sheet\mold metal the initial forming temperature and other parameters,optimal performance parameters of Left anterior column to strengthen parts hot stamping aregained。④Based on the conclusion of BR1500HS ultra-high strength steel heat treatment(quenching)technology and the numerical simulation, a front pillar reinforcement partin car was forming by hot stamping process. Mechanical properties test andmicrostructure of this part are observed. The testing results showed: strength, hardnessand microstructure of the part after hot forming has achieved the quality requirements.The successful practice verifyed the model and the optimized process parameters arereasonable and correct.