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采用氧氮分析仪、扫描电镜、金相显微镜等分析手段,系统研究 LF精炼渣系对304系不锈钢全氧质量分数wT[O]、夹杂物数量、尺寸及成分的影响.研究结果表明,当 LF精炼渣碱度由1.5升高至2.6时,LF出站溶解氧质量分数w[O]由11.6×10－6降低至4.8×10－6,铸坯wT[O]由47×10－6降低至24×10－6,铸坯夹杂物总数量降低,但当量直径不大于10μm的夹杂物所占比率由77.7％增加至95.1％.热力学计算结果表明：在钢液中各元素达到平衡状态时,渣系碱度越高,低熔点夹杂物2MgO?2Al2 O3?5SiO2生成区域越小,MgO?Al2 O3尖晶石类夹杂物生成区域越大,与生产试验结果一致.随着 LF炉渣碱度升高,铸坯夹杂物成分中 MgO 和 Al2 O3的质量分数分别升高了14.4％和9.1％,当碱度不大于1.9时,铸坯中不会存在镁铝尖晶石.

The effect of LF refining slag on number,size,composition of inclusions and T[O]content in 304 stain-less steel were analyzed by oxygen-nitrogen analyzer,scanning electronic microscopy and metallographic microsco-py.The results indicate that mass fraction of dissolved oxygen in 304 stainless steel at LF tapping moment decrea-ses from 11.6×10-6 to 4.8×10-6 with slag basicity in LF refining process increasing from 1.5 to 2.6,and mass fraction of T[O]in 304 stainless steel continuous casting slab decreases from 47×10-6 to 24×10-6 .The number of inclusions in slab decreases,but the proportion of inclusions which diameter less than 10μm increases from 77.7% to 95.1%.The thermodynamical calculation results show that under the condition of equilibrium state, with increasing slag basicity in LF refining process,the formation areas of 2MgO?2Al2 O3?5SiO2 inclusions be-come smaller and the formation areas of MgO?Al2 O3 become bigger,which have the same tendency with produc-tion test.The MgO and Al2 O3 content of inclusions in slab increase 14.4% and 9.1% respectively with slag basic-ity in LF refining process increasing.There are no MgO?Al2 O3 spinel inclusions in continuous casting slab when slag basicity in LF refining process is less than 1.9.