Austempering is a heat treatment process based on the isothermal transformation of austenite to bainite at a temperature above the martensite start temperature. During the austempering process if the austempering holding time is not long enough the bainitic transformation is incomplete, and the residual austenite will transform to martensite during the cooling to room temperature. In the present work, color tint-etching was used to distinguish phases in austempered AISI 5160 steel samples. X-ray Diffraction (XRD) analysis with Rietveld refinement was also conducted and compared with the results determined by tint etching. Both results show that with increased austempering holding time the bainite percentage increases while the martensite percentage decreases. However, the martensite percentage determined by tint etching method is much higher than that determined by XRD analysis in the present work.
展开▼
