Heat Treatment

The main objective of this project work was to asses grinding wear behavior of austempered ductile iron balls. In this project, ductile iron balls were austenitised at 900°c and subjected to two step austempering heat treatment process. In the two step austempering process, the first step temperatures were 300°C for 60 minutes and then up quenched to higher temperature of 400°C for 60 min. Wear studies were carried out in dry and wet grinding conditions, in varying PH values from 7 to 10 and compared these results with En-31 forged steel balls. Same balls were used to grind the iron ore and charcoal. During this two step austempering the wear rate of ADI balls decreases with increasing PH of the mineral slurry, and in wet grinding wear rate is reached a peak values were found because of the corrosion influence. The results of wear study were correlated with microstructural features such as bainitic morphology and volume fraction of retained austenite and ferrite lath size.