| 摘要 |
PURPOSE:To perform refining of steel under good agitation of a steel bath by entraining a solid material which produces a cracked gas easily at the temp. of molten iron into the blowing gas from below the steel bath and chaning the supply rate of said solid material thereby controlling the amt. of the produced gas. CONSTITUTION:A solid material (e.g.; CaCO3) which generates a cracked gas at the refining temp. or below is mixed with a gas (e.g. pure oxygen, N2) to be blown through a tuyere from below the steel bath. In this case, the gas and the solid material are blown simultaneously, and in the second half of the refining, the supply rate of the solid material is increased without increasing the amt. of the gas. More specifically, the supply rate of the solid material is so controlled that the total sum of the blowing gas and the cracked and produced gas increases to 1.5 times or above in about 50% period in the scond half with respect to the time up to about 50% the first half during the refining period. As a result, the agitation of the slag and the metal is improved, the effect of dephosphorization is improved and the superior refining effect of high blowing-out Mn and less T, and Fe in the slag is obtained. |
