Effect of heat treatment parameters on abrasive wear and corrosion resistance of austenitic nodular cast iron Ni-Mn-Cu

Influence of heat treatment parameters on abrasive wear and corrosion resistance of nodular cast iron Ni-Mn-Cu was examined. Chemical composition was selected in such a way, that austenitic matrix was obtained in raw castings (relatively good machinability). Heat treatment, consisting of soaking (450, 550, 650 °C for 4, 8, 12 h) and air cooling, led to partial transformation of austenite. At the lowest temperature, martensite was formed. Raising the temperature and prolonging the soaking time caused increase of austenite transformation degree. At the same time, a gradual change in morphology of the coniferous phase was observed in the direction of fine-acicular ferrite found in bainite or ausferrite. As a result, significant increase in hardness and wear resistance of castings was observed. The heat treatment caused slight changes in gravimetric corrosion rate. However, potentiodynamic studies indicate, that the nature of corrosion from local to uniform was changed. From the point of view of corrosion resistance, this is a very beneficial phenomenon.