| 摘要 |
PURPOSE:To perform refining without causing increase of N quantity in steel at blowing out, by stopping only top blowing at time point when residual quantity of total oxygen necessary for attaining a blowing out target [C] is a specified quantity or more, in blowing by high carbon blowing out method. CONSTITUTION:High carbon steel is blown by high carbon blowing out method, in top blown converter having both functions of top and bottom blowing of oxidizing gas. Thereat, before residual quantity of total oxygen necessary for attaining the blowing out target [C] becomes at least 1.5Nm<3>/t, oxygen supply from top blowing lance is stopped, then decarbonization is carried out up to blowing out only by bottom blowing oxygen. By this method, unavoidable increase of N in steel in blowing of high carbon steel by conventional high carbon blowing out method is suppressed effectively, and blowing ouf for the target [C] can be achieved without increasing [N] quantity. |
