Decarburization behavior of high Cr steel by mixed gas top blowing was investigated in experiments with a 5t inert gas stirred converter.
Results obtained are summarized as follows :
1) Preferential decarburization characteristics in low carbon region are obtained with mixed gas top blowing better than those with oxygen top blowing.
2) A new index, ( CROI ), is introduced to attain good correlation between the operational conditions and the decarburization characteristics in low carbon region.
3) The new index can reasonably explain the difference in the decarburization characteristics in several kinds of the combined blowing converters.
Based on the above results, the refining process for high Cr steel has been commercialized in the 180t combined blowing converter (LD-KGC) at Mizushima Works.
