Nitrogen absorption by 04Kh18N10 steel in plasma-arc melting under slag of CaO–Аl₂O₃ system

Abstract

Nitrogen as an alloying element of steel is a strong austenitizer, and it has an essential influence on mechanical properties of steels of different grades. It is rational to use gas phases for nitrogen alloying, and the process can be intensified with the application of highly-concentrated energy sources, for instance, plasma. One of the determining factors of metal alloying is the partial pressure of nitrogen and the process temperature. It is difficult to find works, dealing with nitriding of metal melts in plasma-slag process. the paper gives experimental data on dissolution kinetics and nitrogen solubility in 04cr18ni10 steel. The derived mathematical models of nitrogen dissolution in plasma melting are highly significant, which is indicated by the respective determination coefficients. At less than 0.1 atm partial pressure of nitrogen above the melt, the temperature in the range of 1823-2323 K practically does not influence the content of nitrogen in steel, and at a higher partial pressure, the content of nitrogen in steel decreases with the temperature rise. the melt temperature under the experimental conditions was assessed as 2385 K. It was determined that the coefficient of nitrogen distribution between the metal and slag changes only slightly at up to 1 atm partial pressure of nitrogen and is equal to 1.1-1.2.