Research On Several Fundamental Properties Of Automobile Hot Forming Steel22MnB5and Its Application

For guiding real hot forming process and providing numerical simulation of hot stamping accumulation and experience, several fundamental properties of22MnB5, the hot stamping steel, are studied and explored through experiments and computer simulations.First, based on scanning X-ray fluorescence spectrometer, components of22MnB5are determined. Secondly, mechanical properties, such as tensile strength, bending strength, stress-strain relationship and etc., are obtained through basic experiments. A special V-shaped hot bending test is designed through which the optimal temperature zone for bending forming is obtained. Then bending test of real anti-collision beams was conducted to validate the V-shaped test results. For studying the impact of stamping temperature on hot forming, the plate and U-shaped water cooling molds are designed. And the optimal temperature zones are acquired through studying plate and U-shaped samples stamped at different temperatures. Finally,22MnB5lightweight potential is assessed using the self-developed vehicle concept design system, VCD_ICAE. Besides, numerical simulations are conducted on three-point bending test and V-shaped test. References are provided for hot forming simulation and its software development, since results of experiment and simulation match well.On the basis of researches above, main conclusions achieved are as follows:(1) The tensile strength of22MnB5achieves1500MPa after quenching, about3times as high as no-quenching, and bending strength and bending energy absorption are promoted by2-4times. It’s indicated hot forming, simultaneous forming and quenching, can significantly improve the forming parts strength and energy absorption capability(2)600-7000℃is the optimal temperature zone for hot bending, at which finer martensite texture and smallest springback amount can be formed.(3) The optimal stamping temperature zones of22MnB5may be different for tension and bending. So the stamping temperature should be set according to tension and bending standard of the part in real production.(4) After hot forming parts introduced, the auto body mass is reduced by10.76%in VCD_ICAE and its bending and torsion rigidity are promoted slightly simultaneously, which shows huge lightening potential of22MnB5.