1966 Volume 52 Issue 12 Pages 1738-1748
Under various conditions the liquid iron-carbon alloys were oxidized by blowing A-O2 gas onto the surface of the melt and the decarburization process was followed by sampling either the melt or the gas phase. The results obtained are summarized as follows:
1. In high carbon range the rate of decarburization is independent of the C content and increases in approximate proportion to the oxygen concentration in A-O2 gas. The O content remains constant before the C content reaches the critical values which depend on the oxygen concentration in the gas.
2. In low carbon range the rate of carbon removal decreases as the C content decreases. The reaction was accompanied by the emission of iron oxide fume and an increase of the O content.
3. When the alumina tube is situated at a distance of 25mm from the surface, the rate of carbon removal is independent of its area and, therefore, the reaction takes place merely on the small portion of the surface. Owing to the gaseous diffusion into the A-O2 gas stream, about 10 minutes is necessary for the decarburization to reach steady state.
4. When the tube is located at a distance of 125mm, the rate of decarburization is much lower than in the case of 25mm within the range of oxygen concentration 0-40% and in this range the fume is evolved noticeably.
5. In high carbon range the oxygen in the gas burns the evolved CO and the reaction O2+2CO=2CO2 goes on to completion at the flame front.
6. The rate of decarburization increases as temperature lowers, especially in the case where the tube is located at a distance of 125mm.
7. The mechanism of the formation of iron oxide fume is discussed in relation to the rate of vaporization of molten iron and the flux of CO2 which diffuses through the vapor phase.
8. It is confirmed that in both ranges of C content the gaseous diffusion to the surface of the melt controls the decarburization in these experiments.