Effect of Pearlitizing on the as cast and as heat-treated Microstructure of Hadfield Steels

In this paper, the effects of pearlitizing on the as cast and as heat-treated microstructures of austenitic manganese steel (named Hadfield steel) were evaluated. The samples with different contents of carbon and manganese were produced using induction furnace and precision casting method. The as-cast, annealed, and solution treated microstructural studies were performed by optical microscopy, X-ray diffraction, ferritescopy and field emission scanning electron microscopy. The microstructural results showed that the as cast and annealed microstructures of the steel in room temperature consist of austenite matrix, carbide and ferrite. Fine examination by scanning electron microscope shows that the ferrite and carbide phases are formed as pearlitic colonies. It was also observed that the increase in carbon content and annealing heat treatment are more facilitated the pearlitizing. By applying the final heat treatment (solution and quenching in water), pearlite colonies convert to new fine austenite grains and then the austenite grains sizes are decreased.