Experimental and theoretical studies were carried out to quantitatively understand the effects of geometry such as a vacuum vessel and snorkels on the decarburization rate and final carbon content in the RH degasser.
The inner diameter of snorkel was varied between 0.6 and 1.0m, the cross-sectional area of the vacuum vessel between 3.5 and 5.1m2 and the amount of steel melt between 240 and 300t in the experiments made at Mizushima works. The reaction rate was increased and the final carbon content was decreased with the increase in the snorkel diameter and the cross-sectional area of the vacuum vessel, and with the decrease in the amount of molten steel. The maximum decarburization rate and a minimum final carbon content to less than 10 ppm were attained with the largest vacuum vessel whose inner diameter was 1.0m and the cross-sectional area was 5.1m2. The relation between the final carbon content and the initial decarburization rate was found quantitatively in the experiment.
The experimental results agreed well with calculated values on the basis of the theoretical analysis and proved that it is possible to determine the geometry of the RH vacuum vessel required to obtain a specified aimed carbon content.
