REFINING METHOD FOR MOLTEN STEEL,申请号JP20130236979-传众专利搜索

REFINING METHOD FOR MOLTEN STEEL

申请公布号：JP2015096639(A)

申请号：JP20130236979

申请日期：2013.11.15

申请公布日期：2015.05.21

申请人：

NIPPON STEEL & SUMITOMO METAL

发明人：KASAHARA SHUHEI;NISHI TAKAYUKI

分类号：C21C7/10

主分类号：C21C7/10

摘要：<p>PROBLEM TO BE SOLVED: To provide a refining method for molten steel which improves refining characteristics even for the same circulation gas flow rate and not only increases the circulation amount but improves refining characteristics when the circulation gas flow rate is increased.SOLUTION: Circulation gas bubbles in a vacuum tank are dispersed, even when the bath depth is small, and, to increase the kinetic energy transfer efficiency of the circulating gas flow rate, blowing tuyere ports for the circulation gas is adjusted so as to be at an angle of 15-60° horizontally to the straight line connecting the tuyere ports to the center of an immersion tube and so that the index (G/(n.A.d)) related to the circulation gas flow rate meets equation (2), in a condition that the inside diameter of the vacuum tank of a circulation type vacuum degasification treatment apparatus and the bath depth of molten steel in the vacuum tank meet equation (1). Equation (1): 0.025≤h/D≤0.30, where h is the bath depth (m) in the vacuum tank; D is the inside diameter (m) of the vacuum tank. Equation (2): 50≤G/(n.A.d)≤570, where G is the circulation gas flow rate (Nm/s); n is the number of tuyere ports (-); Ais the cross-sectional area (m) of the circulation gas blowing tuyere; and dis the diameter (m) of a riser tube.</p>