Precipitation and Dispersion Control of MnS by Deoxidation Products of ZrO₂, Al₂O₃, MgO and MnO–SiO₂ Particles in Fe–10mass%Ni Alloy

Abstract

An Fe–10 mass%Ni–1mass%Mn alloy was deoxidized with Zr, Al, Mg and Si and the effect of these deoxidation particles on MnS crystallization and/or precipitation has been studied as a function of S content with forcussing on the particle dispersion in microsegregation domain. MnS cannot be uniformly dispersed in microsegregtion domain since the crystallization and/or precipitation of MnS occur only on ZrO₂ or Al₂O₃ particles located at the region of final solidification. MnS-containing MnO–SiO₂ particles can be uniformly dispersed in microsegregation domain, if the S level is low enough for particles not to be pushed. MgS and/or (Mg, Mn)S crystallize on MgO particles in Mg deoxidation. In the case of high S level, the MgO, MgS/MgO and (Mg, Mn)S/MgO particles are pushed to the region of final solidification and then MnS crystallizes and/or precipitates on the pushed particles.