Evolution of TiS and TiN in Fe-40 MassPctNi Austenitic Alloy During Heating at 1273 K (1000 °C)

Evolution of TiS in composition and morphology as well as the change in size distribution of TiS and TiN in Fe-40 masspctNi austenitic alloy during heating at 1273 K (1000 °C) was investigated using manual/automatic scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM/EDS). Two types of TiS morphologies, spindle and spherical, were maintained during heating. The molar ratio of Ti/S of TiS increased while the aspect ratio of TiS was maintained in both alloys during heating. The number density of TiN inclusions was low compared with TiS in each alloy during heating. The pinning effect of TiS during heating was confirmed, and was stronger in alloy with a larger volume fraction of TiS. The results contribute to the establishment of optimum heat treatment processes for austenitic stainless steel to obtain better pitting corrosion resistance.