Microstructural investigation of cast medium-manganese austenitic steel with composite surface

The microstructure of cast composite surface of a medium-manganese austenitic steel has been investigated. The oxide amount is decreased from 0.035% to 0.007%, the sulfide amount from 0.029% to 0.01%, and the sphericity of the inclusions is changed from 1.43 to 1.03. NbN and Nb2C can act as heterogeneous nuclei for austenite manganese steel. A high Cr-containing casting surface with thickness 7.2 mm and hardness HV897 is formed after casting the surface composite.