Influence of austempering temperatures on microstructure and wear performance of solution strengthened ferritic ductile cast irons

The object of this study was to analyze the effect of diverse austempering temperature on microstructure of solution strengthened ferritic ductile cast irons. Austempering was carried out at 300, 500, 550 and 600 °C for period of 3 h followed by air-cooling. Samples were examined by using scanning electron microscopy (SEM) and X-ray diffraction. The adhesive wear experiment of the samples was done in dry sliding conditions. The worn surface of the sample was examined by SEM. The dimensions and proportions of the ausferrite and bainitic phases in the matrix changed with the austempering temperature. The nodules exhibited very good dispersion behavior in the solution strengthened ferritic ductile iron matrix. The transformation of acicular ferrite showed a significant bainite characteristic. The rate of wear increased with the increasing austempering temperature.