Decarburization Reaction in Ultra-low Carbon Iron Melt under Reduced Pressure

Abstract

The kinetics for the decarburization of iron melt in the ultra-low carbon range under reduced pressure were studied, using an induction furnace with a 20 kg melt. The results obtained are as follows:
1) The decarburization reaction proceeded to less than 5 ppm of carbon, and the decarburization rate constant, K, decreased as the carbon content decreased.
2) As the pressure in the chamber decreased, the decarburization rate increased with a carbon content of more than 10 ppm. On the contrary, the dependency of decarburization rate on the pressure in the chamber was small with less than 10 ppm of carbon.
3) As the influence of the sulfur content on the decarburization rate was small with a carbon content of more than 10 ppm and the decarburization rates were also not affected by the mass transfer of CO in the gas phase under the experimental conditions, it is concluded that the decarburization rate was controlled by the mass transfer of carbon in liquid iron.
4) The fact that the decarburization rate with a carbon content of more than 10 ppm was affected by the total pressure of the chamber was explained by the change in interfacial area of the reaction between the gas and liquid phases resulting from CO boiling in the bulk melt.