Modeling and simulation of hot stamping process for medium manganese steel alloy

In this study, a new medium manganese (medium-Mn) steel alloy is developed for the hot stamping process and required material properties were obtained. The differences of microstructural and mechanical behaviors among typical 22MnB5 steel and medium-Mn steel are investigated during the hot stamping both in uncoated condition. The commercial Finite Element software PAM-STAMP is employed for the simulation of the hot stamping. ThermoCalc and JMatPro are used for the calculation of necessary thermophysical properties. The hot ductility and fracture behaviors of medium-Mn steel are investigated by Gleeble hot tensile experiments over the deformation temperatures of 600-900 degrees C and strain rates of 10(- 3) and 10(- 4) after annealing at different temperatures during the thermomechanical process. Dilatometer tests were conducted to obtain the phase transformations. Hot tensile testing and dilatometry studies indicated that the hot tensile behavior of medium-Mn steel is influenced by the microstructural alterations occurred via cooling or heating prior to the deformation. To validate the thickness distribution and the microstructural evolution, a prototype part is manufactured on a semi-industrial scale by hot stamping for both materials. A good correlation between simulation and experiments was observed. In addition, decarburization of the part is investigated. medium-Mn steel exhibited a lower decarburization layer. It was also seen that the higher hardenability of medium-Mn steel favors the martensitic transformation.