Microstructure and mechanical behaviors of grinding balls produced by dual matrix structure two-step austempering process

The austempered ductile iron (ADI) grinding balls were austenitized at 900 °C for 2 h and then incomplete quenched in a sodium silicate solution for 100 s, after that austempered in an isothermal furnace at 230 °C for 1 h. Different from the two-step austempering process, this process can prepare a two-phase structure through the incomplete quenching stage and austempering stage, so we called it a dual-matrix structure (DMS) two-step …