Influence of Slag System Ingredients on Hydrogen Content in 316H Stainless Steel for Electroslag Remelting in Nuclear Power Applications

Abstract

During the process of electric arc remelting， the content of gas components （such as H， O， N， etc.） in the steel is significantly influenced by the gas permeability of the slag system used. In order to explore a slag system with low hydrogen permeability suitable for nuclear-grade 316H stainless steel in electric arc remelting， the hydrogen permeability of five slag systems used in electric arc remelting was determined. The results showed that the newly developed 63%CaF2-30%Al2O3-7%MgO slag system had the lowest hydrogen permeability.meanwhile the hydrogen permeability of slag system， 65%CaF2-30%Al2O3-5%MgO， was similar to that of the 63%CaF2-30%Al2O3-7%MgO slag system， and hydrogen permeability of both slag systems exhibited a significant reduction compared to the original slag system used in the steel plant's electric arc production，declined from 6.58×10-6 mol/（cm·min） to 1.89×10-6 mol/（cm·min） and 2.18×10-6 mol/（cm·min） respectively.The higher the optical basicity of the slag was， the higher the hydrogen permeability was. CaO in the slag had a high affinity for water and can easily increase the hydrogen content in the steel ingot during electric arc remelting， while the addition of MgO in the slag system can significantly reduce hydrogen permeability. Under the research conditions， the influence of the slag system's constituents on its hydrogen permeability was more significant than the optical basicity.

Keywords

• electric slag remelting； austenitic stainless steel； 316h； nuclear power； hydrogen content