| 摘要 |
PURPOSE:To obtain easily low P steel contg. <=0.01% P at a low cost, by adding a specified amount of a dephosphorizer having a specified composition composed essentially of CaO, Al2O3, Fe3O4 and Na2CO3 to molten steel and by refining the molten steel. CONSTITUTION:The composition of a dephosphorizer is composed essentially of, by wt., 50-60% CaO, 10-20% Al2O3, 15-20% Fe3O4 and 10-17% Na2CO3. Molten slag consisting of said four components has 1,400-1,420 deg.C m.p. The dephosphorizer is added to molten steel by 15-20kg per 1ton molten steel, and the molten steel is refined by dephosphorization. The dephosphorizing action is performed by forming a compound together with phosphorous oxide oxidized with Fe3O4. At the same time, Si in the molten steel is oxidized to SiO2. |
