Research on Cleanliness of 27SiMn Steel Produced by BOF-LF-CC Process

The cleanliness of 27SiMn tube billet produced by BOF-LF-CC process in a domestic steel mill is studied by the way of sampling systematically and comprehensive analysis.The results show that the quantity of microinclusions decreases from 35.0 to 8.4 per square millimeter after LF.The quantity of total oxygen and inclusions contents increases obviously in tundish.The average total oxygen content is(24~30)×10^-6 in round billet, and macroinclusion in it is 0.487 mg/kg.The main factors affecting the steel cleanliness are revealed based on research results, such as reoxidation caused by burning oxygen and pouring unstably and slag entrapment in mold.Then some measures of improvement process are proposed pointedly.