| 摘要 |
<p>PURPOSE:To produce an extremely low sulfur steel. CONSTITUTION:Into molten steel, Ca alloy and flux having composition of CaO/Al2O3=0.4-1.5, are added at the same time. At first, a pair of the Ca alloy is added and after that, the remaining Ca alloy and flux may be added at the same time. As CaO.Al2O3 of low m.p. composition always exists near CaS produced with desulfurizing reaction of the Ca alloy, absorption of CaS with the CaO.Al2O3 is progressed and it is made to little that CaS is independently dispersed or aggregated in group-state, and spheroidization of inclusion is progressed. As S content can be lowered to <=0.005% by adding a sufficient quantity of the Ca alloy, the production of high quality steel, such as steel for high grade line pipe, can be utilized.</p> |
