Effect of heat treatment on microstructure, mechanical properties and erosion resistance of cast 23-8-N nitronic steel

Effects of heat treatment on microstructure, mechanical properties and erosion behavior of cast 23-8-N nitronic steel were studied. A series of heat treatments were carried out in the temperature range of 1180-1240 °C to observe the effect on microstructure. Optimum heat treatment cycle was obtained at 1220 °C for holding time of 150 min, which leads to dissolution of carbides, formation of equiaxed grains and twins. Heat treatment has shown improvement in tensile strength, toughness, impact strength and work hardening capacity, however at the cost of marginal reduction in hardness and yield strength. This resulted in improvement of erosion resistance of cast 23-8-N nitronic steel. The microstructures, fractured surfaces and phases were studied by optical microscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis respectively.