Influence of atomisation on solidification microstructures in the rapidly solidified powder of the Cr–Mo–V tool steel

The paper deals with the analysis of microstructure formation in the tool steel of ledeburite type under quasi-equilibrium and non-equilibrium conditions. The quasi-equilibrium solidification behaviour was investigated by differential thermal analysis. The rapidly solidified powder was produced by the nitrogen gas atomisation. Three main types of solidification microstructures were observed in all granulometric fractions of rapidly solidified powder: dendritic, grain refined and compound (a mixture of dendritic and grain refined). Mechanism of microstructure transition from dendritic to non-dendritic was described.