Warm Stamping Technology of the Medium Manganese Steel

A kind of hot stamping technology with lower heating temperature, as named as warm stamping, is proposed based on the medium manganese steel. The differences on the microstructure and mechanical properties among 22MnB5 steel, Al–Si coated 22MnB5 steel, and medium manganese steel are studied before and after hot/warm stamping process based on industrial trail. The results show that the tensile strength of 1500 MPa is obtained for medium manganese steel when the austenitizing temperature is only 800 °C, much lower than 950 °C for 22MnB5 steel. Finer microstructure of medium manganese steel is obtained by warm stamping and there is no surface decarburization under atmosphere environment. The total elongation of warm‐stamped medium manganese steel reaches 10%, which is higher than that of 7.5% for 22MnB5 steel. The excellent hardenability makes warm‐stamped medium manganese steel more suitable for the production of large‐size components with martensitic microstructure. The results of spot welding test between medium manganese steel and H340LAD + Z show that the welding performance meets the requirement of automobile plant.