The Effect of Austenitizing Process on the Hardening Behaviour of Cr-Mo-Mn-C Air-hardening Cast Tool Steel

Abstract

The hardening behaviour of Cr-Mo-Mn-C air-hardening cast tool steel was investigated by using an electron microprobe analyser (EPMA), a transmission electron microscope (TEM), an energy dispersive X-ray diffraction spectrometer (EDS), as well as scanning electron microscope (SEM). The results obtained in the present investigation show a significantly different behaviour in the Cr-Mo-Mn-C air-hardening cast tool steel. It is concluded that the performance of (Fe, Cr)₃C dissolution and (Cr, Fe)₇C₃ reprecipitation during austenitizing is a key factor controlling the hardening behaviour as well as ultimate hardness obtained in air cooling.