Abstract: By calculation on thermodynamic equilibrium of Fe-Al-Ca-O-S system in calcium treatment process, the digrams of equilibrium curves of [ Al]-[O] , [Al]-[Ca] and [Al]-[S] in each equilibrium condition at 1873K are obtained ,and the effect of each component on modification of inclusions is systematically analyzed. It is found by study that in condition of 0.02%~0. 03% [Al] in F-grade high strength ship plate steel, in order to insure full accomplishing modification of inclusions, the [O] in steel should control less than 25X10^-6; with forming 12CaO·7Al₂O₃ in liquid the [Ca] is 15.24x10-⁶~19.97x10-⁶, and with forming 3CaO·Al₂O₃ in liquid the [Ca] is 70.87x10^-6~ 92.88x10^-6； and with lower temperature of liquid it is available to form CaS and inhibit MnS clustered precipitation. The results of commercial production of F-grade high strength ship plate steel DNV F40 (/%: 0.092C, 0.41Si, 1.56Mn, 0.015P, 0.002S, 0.032Al, 0.035Nb, 0.010Ti, 0.080V) by 120t BOF-LF-VD-slab casting flowsheet show that with LF refining slag ingredient/% : 24.9Al₂O₃,55.6CaO, 7.7MgO, 8.0SiO₂ and 1.24TFe, aluminium content in steel 0.03% and oxygen content in steel 0.0010% before adding calcium, and per heat feeding pure calcium wire 150m(0.21kg/m) , the inclusions in steel modified to spheroidal calcium aluminate inclusions from Al₂O₃ before adding calcium.

摘要： 通过钙处理过程中Fe-Al-Ca-O-S体系的热力学平衡计算,得出在1873 K时各种平衡态下的[Al]-[O]、[Al]-[Ca]、[Al]-[S]平衡曲线图,并系统分析了各组元对夹杂物变质的影响。研究发现F-级高强度船板钢[Al]为0.02%~0.03%时,为保证夹杂物充分变质,钢中[O]控制在25×10^-6以下;钢液中生成12CaO·7Al₂O₃的[Ca]为15.24×10^-6~19.97×10^-6,生成3CaO·Al₂O₃的[Ca]为70.87×10^-6~92.88×10^-6;适当低的钢液温度有利于生成CaS,抑制MnS的聚集析出。120t BOF-LF-VD-板坯连铸流程生产F-级高强度船板钢DNV F40（/%:0.092C,0.41Si,1.56Mn,0.015P,0.002S,0.032Al,0.035Nb,0.035Ni,0.010Ti,0.080V）的结果表明,当LF精炼渣组成/%:24.9Al₂O₃,55.6CaO,7.7MgO,8.0SiO₂,1.24TFe,加钙前钢中铝含量0.03%,氧含量0.0010%时,每炉钢水喂纯钙线150m（0.21 kg/m）,钢中夹杂物由加钙前Al₂O₃变质为球形钙铝酸盐夹杂物。 

关键词: F-级高强度船板钢DNVF40 , BOF-LF-VD-CC流程, 钙处理, 热力学计算, 夹杂物变质