Abstract: According to the results of analysis on performance of present mold powder FRK-2 and FRK-49 at steel works, based on mold powder FRK-2 (/% ： 32. 68SiO₂, 24.42CaO, 3. 30MgO, 9. 52Al₂O₃, 5.40Na₂O, 3. 10Fe₂O₃, 3. 59F^- , 12. 60C) a mold powder for casting 150 mm x 150 mm billet of free cutting steel X1215 (/% ： 0. 06 ~0. 09C, ≤ 0. 10Si, 1. 20 ~ 1. 50Mn, 0. 08 ~0. 10P, 0. 30 ~0. 50S) with higher basicity, nice holding effect, lower viscosity and definite reducing capacity to decrease S and 0 content in liquid at meniscus and avoiding slag entrapment has been developed. Production results show that the performance of mold powder meets the requirement for production of low carbon and high sulfur free cutting steel X1215; the segregation index of alloy elements in steel is 0. 90 ~ 1. 10, the segregation index of S and Mn is respectively 0. 95 - 1. 05 and 0. 98 - 1. 03 ； and the billet has nice internal quality.

摘要： 根据炼钢厂现有结晶器保护渣FRK-2和FRK-49性能分析的结果,以FRK-2保护渣(/%:32.68SiO₂、24.42CaO、3.30MgO、9.52Al₂O₃、5.40Na₂O、3.10Fe₂O₃、3.59F^-、12.60C)为基础开发了较高碱度,保温效果好,较低粘度,有一定还原性以降低弯月面处S和O含量,并避免卷渣的X1215易切削钢(/%:0.06～0.09C、≤0.10Si、1.20～1.50Mn、0.08～0.10P、0.30～0.50S)150 mm×150 mm铸坯连铸结晶器保护渣。生产结果表明,保护渣性能达到X1215低碳高硫易切削钢的生产要求;连铸坯合金元素偏析度均为0.90～1.10,S和Mn偏析度分别为0.95～1.05和0.98～1.03,连铸坯内部质量良好。

关键词: 易切削钢X1215, 结晶器保护渣, 150 mm X 150 mm连铸坯 , 成分偏析