Carbon Solution in Liquid Iron and Iron Alloys

The dissolution of carbon into liquid iron and iron alloys was investigated using four independent experimental approaches, i.e., immersion of a graphite cylinder in a melt bath using an electric resistance furnace, immersion of a coke particle in a melt bath using an induction furnace, a molten droplet on a graphite plate using an induction furnace and sliding a metal droplet down a graphite spiral in a resistance furnace. The dissolution rate was analysed by assuming that this reaction is governed by the diffusion of carbon from the carbon-metal interface to the bulk liquid metal through a boundary layer. The experimental results for each case were well interpreted by both concentration and activity driven models. The variation in the carbon dissolution rate with the experimental method was explained by the Olsson relation or the penetration theory. An increase in carbon dissolution rate with temperature was observed. The carbon dissolution rate into liquid Fe-C alloy was not changed by addition of 1.9 wt% silicon to the melt, while a decrease in the dissolution rate of carbon was observed by adding 1 wt% sulfur to the melt.