Development of Oxygen Top Blowing and Argon Bottom Blowing Method in Refining of Stainless Steel

Abstract

Refining of stainless steel by oxygen top blowing and argon bottom blowing was investigated by using a 2.5 t laboratory scale converter. It was found that stainless steel can be produced in a top and bottom blowing converter by using argon bottom blowing as well as in AOD method because agitation of molten steel and dilution of CO gas with argon bubble are satisfactory. This method was successfully applied to the 15 t pilot scale converter and the 160 t industrial scale converter on the basis of the experimental results at the 2.5 t laboratory scale converter. From the study of decarburization rate and chromium oxidation at low carbon region, it was found that coefficient of decarburization rate was mainly controlled by interfacial area of argon bubbles and also could be increased by strong bath agitation. It was also seen that chromium oxidation proceeds with oxygen which was not consumed for decarburization.