MANUFACTURE OF FREE-CUTTING STEEL

摘要

PURPOSE:To reduce the amounts of starting materials for P and S used and the amount of CaO used when a free-cutting steel contg. a prescribed amount of P and/or prescribed amount of S is manufactured by refining, by substituting slag for part of CaO used as a slag forming agent. CONSTITUTION:Slag used once for refining is added to a molten steel contg. <=0.13wt% C and 0.7-1wt% Mn. The slag is a substitute for part or all of CaO as a slag forming agent. A free-cutting steel contg. 0.05-0.12wt% P and/or 0.07-0.35wt% is manufactured by refining.