Effect of Niobium on Nitrogen Solubility in High Chromium Steel

Abstract

The interaction parameters of alloying elements on nitrogen in liquid Fe-Cr alloys containing niobium have been determined. The equilibrium nitrogen solubility in the liquid iron alloy was measured by metal-gas equilibrium technique under 0.04 to 1.0 atm of nitrogen atmosphere at 1 823 to 1 923K. Nitrogen solubility in Fe-Cr-Nb melts obeyed Sieverts' law for all compositions studied in present study.
The results obtained are summarized as follows;
(1) The solubility of nitrogen markedly increased with increasing chromium and niobium. The interactionparameters in liquid iron alloys containing 10-18 % of Cr and 0.2-2 % of Nb are obtained.
(2) The solubility of nitrogen was lower at a higher temperature in Fe-Cr melts in this study.
(3) Test results indicated that it is not likely to form niobium nitride in Fe-Cr-Nb-N alloys and it was confirmed by EDS.