Investigation of the change in mechanical properties by austempering heat treatment of ductile irons containing molybdenum and nickel

In this study, austempering heat treatment has been optimized for ductile irons (DI) containing molybdenum and nickel. In addition to the composition of GGG-70 ductile iron material, ductile iron was produced by adding molybdenum and nickel elements. Heat treatment was applied to the samples whose production processes were completed. Austenitization was carried out for 2 hours in the temperature range of 930°C. The austenitized samples were quenched in a salt bath up to temperatures of 320 °C and 350 °C at a cooling rate that did not cut the pearlitic zone, taking into account the time-temperature conversion graph. Then, the samples were kept at 320 C or 350 C for 90 minutes. After the heat treatment process has been completed, spectral analysis, metallography, tensile tests, hardness tests, microstructure analysis with the help of optical microscope in order to determine the mechanical and metallurgical properties of the materials.