Abstract: The steelmaking flowsheet of tested bearing steel GCr15 (/%: 1.00C, 0.20Si, 0.39Mn, 0.015P, 0.005S, 1.50Cr, 0.003Ti, 0.015Als) is pre-desulphurized hot metal-100t BOF-LF-RH-200mmX200mm billet casting. The main process characteristics are adding 1.2kg/t aluminium for pre-deoxidation in BOF tapping, using white slag operation in LF refining with initial slag main ingredient (/%: 22Al₂O₃,56CaO, 10SiO₂, 5MgO), RH 67Pa for 25min and shield casting in cast process. Analysis results of two heats malting show that the oxygen and nitrogen content in liquid at end RH are lowest respectively  7X10^-6~8x10^-6 and 24x10^-6~26x10^-6, the size of majority inclusions in steel is 3~8μm, and the number of inclusions in steel at unit area is lowest at end RH, and the main nonmetallic inclusions in cast billet are Al₂O₃-CaO; with condition of high basicity refining slag the calcium aluminate easily reacts with magnesiumaluminum spinel, with slag basicity 2~3 the small amount of MgO-Al₂O₃ occurs and with slag basicity more than 4 the MgO-Al₂O₃ series inclusions don't occur, besides with condition of high basicity the MgO content in MgO-Al₂O₃-CaO series inclusions is able to decrease.

摘要： 试验GCr15轴承钢（/%:1.00C,0.20Si,0.39Mn,0.015P,0.005S,1.50Cr,0.003Ti,0.015Als）的冶炼工艺流程为预脱硫铁水-100t BOF-LF-RH-200mm×200mm坯连铸。主要工艺特点为BOF出钢过程加1.2kg/t铝脱氧,LF精炼采用白渣操作,精炼初渣主要成分为（/%:22Al₂O₃,56CaO,10SiO₂,5MgO）,RH67Pa,25min,连铸过程保护浇注。两炉钢冶炼分析结果表明,钢中氧氮含量在RH破空样品中同时达到最低分别为7×10^-6~8×10^-6和24×10^-6~26×10^-6,钢中非金属夹杂尺寸主要集中在3~8μm,并且单位面积夹杂物数量在RH破空样中达到最小;铸坯中非金属夹杂以Al₂O₃-CaO夹杂为主;在高碱度渣的条件下,钙铝酸盐与镁铝尖晶石很容易发生反应,碱度为2~3时会出现少量MgO-Al₂O₃,在渣碱度达到4以上时不会出现MgO-Al₂O₃系夹杂物,并且高碱度条件下MgO-Al₂O₃-CaO系夹杂物中MgO含量会降低。

关键词: 100t BOF-LF-RH-CC流程, 轴承钢GCr15, 夹杂物, 尺寸, 成分, 演变