Hydrogen permeability of slags containing calcium fluoride

Abstract

To investigate the hydrogen permeability of calcium fluoride used for electroslag remelting (ESR) process, “Gas-slag-metal” osmosis process under argon atmosphere saturated with water vapor at 318 K was used to study the hydrogen permeability of slag containing calcium fluoride. The results indicate that the conventional slag, consisting of 70% CaF₂ and 30% Al₂O₃, has the lowest hydrogen permeability. A parameter E_H was proposed for evaluation of the hydrogen permeability of slags containing calcium fluoride. The hydrogen permeability decreases with increasing E_H to a certain extent. An appropriate choice of slag for the ESR process can be obtained. These results also suggest that the hydrogen pick-up in steel after remelting might be reduced when a slag with low hydrogen permeability is used.

Keywords

electroslag remelting / hydrogen permeability / diffusion / calcium fluoride / slag