Experiment Research On The Hot-stamping Of Automobile Anti-collision Beam

A new technology of metal sheet forming called hot stamping technology is developed inrecent years, which mainly is used to produce high strength pieces of automobile body. Thebasic principle is that the blank which is heated to austenitizing temperature is stamped andquenched to make the metallurgical organization of processing components change from theoriginal mixture of ferrite and pearlite into martensite and meet the requirements of highstrength and high hardness. Improve the precision of shapes and sizes greatly, solve the issuesthat the high strength steel parts springback, wrinkling and crack in the forming process.In this paper take the automobile anti-collision beam parts for example, carry through thenumerical simulation of hot stamping forming technology, design mould, analyze the experi-mental results and provide guidance for hot stamping actual production, the main research workhas a few points:1. The numerical simulation for hot stamping of anti-collision beam. Through the use ofPam-Stamp₂G2011software the numerical simulation of process of hot stamping is carriedout. Set up the finite element model based on the theory of the numerical simulation of hotstamping. The paper mainly analyzes the influence of BHF, mould clearance, friction coefficienton the hot forming process and the microstructure after forming. Optimize reasonable parame-ters of forming process. The results indicate that: the BHF influence the forming effect in a largeextent. BHF is larger, sheet is more thinner obviously; the friction coefficient affects the flow ofthe sheet and it is greater, more obvious metal sheet thins; the mould clearance is greater, thethickness is bigger, but it affects the shaping accuracy if it’s too great; the microstructure aremartensite after quenching and are uniformly distributed. 2. Design hot stamping mould of anti-collision beam. According to the hot stamping processcharacteristics, puts forward the cooling system design principle, design the hot stamping mouldstructure and cycling cooling water, discuss the way to seal. Research shows that the coolingsystem must ensure effectiveness, uniformity, sealing and avoid cooling blind area; the mouldstructure includes: convex, concave die, module installed board, blank holders, guide plate, etc.and water circulation is connected in parallel. But module seal way needs to be improved.3. Hot-stamping experiment of anti-collision beam is operated. Produce the actualhot-stamping mould and carry through experiments of direct hot forming and indirect hot form-ing respectively. Introduce the material of hot-forming mould in detail. Compare and analyze themacro-morphology, microstructure, micro-hardness, tensile strength of parts which are producedthrough two kinds of forming methods. The results show:1) Macro-morphology. The parts got through hot forming have no springback and the preciseof contour profile is accurate. But the sheet in high temperature is seriously oxidized, whichmake the surface quality not good. It is to be a problem that the appearance of oxide skin is con-trolled in hot-forming process. When the BHF increases, thinning phenomenon in the round thepart is more evident.2) Microstructure. The microstructure of parts got through direct and indirect hot forming ismartensite. And it is homogeneous along the sample geometry.3) Micro-hardness. Get the samples from the five different positions of beam. Go on the mi-cro-hardness test. Its hardness distribution is homogeneous, and more than450HV. The averagehardness value of parts obtained from direct hot forming is491HV and the one from indirecthot forming is485HV.4) Tensile strength. Carry out tensile test of parts. The strength of parts from the two pro-cesses promotes dramatically and reaches1500MPa above. The elongation drops and the abilityof deformation resistance strengthen. It fully meets the requirement of shock resistance neededby practical production.