Effects of Mn on the microstructure morphology and phase transformation of medium manganese wear resistant steel

The effects of Mn on the microstructure morphology,phase transformation and mechanical properties of medium manganese wear resistant steel were investigated by DIL805 A thermal analyzer,scanning electron microscopy,electron back-scattered diffraction,transmission electron microscopy and mechanical testing. When the mass fraction of Mn increases from 3% to 9% by a 2%increment,the volume fraction of austenite at room temperature gradually increases. The tensile strength and hardness decrease especially at the mass fraction of Mn from 5% to 7%. The orientation relationship between martensite and austenite varies. The morphology and type of martensite change from lath α martensite whose substructure is mainly dislocations to bunchy laminar α martensite and laminar ε martensite whose substructure is mainly dislocations,twins through phase transition and stacking faults.