Influence of Nickel on Niobium Nitride Formation in As-Cast Stainless Steels

The influence of the nickel content and cooling rate on niobium nitride precipitation in as-cast stainless steels were analysed. Niobium microalloying is important for mechanical properties prevention intergranular corrosion steels. However, coarse precipitates can negatively affect steel properties. NbN depends thermodynamic conditions, which are dictated by chemical composition temperature. computations used to estimate precipitation. Additionally, segregation models predict Three batches with different contents (9 wt.%, 4.7 0.16 wt.%) prepared an induction furnace cast into sand moulds. polished etched samples examined optical microscope, followed a more detailed examination using scanning electron microscope. An automatic microscope analysis particles was performed obtain particle number size distribution. Primary carbonitrides, eutectic phases, heterogenous nucleations MnS inclusions observed. As proportion solution decreased, solubility nitrogen melt increased, manifested lower formation primary while non-metallic played role heterogeneous nucleation.