高强度船板钢钙处理热力学计算分析-夹杂物变质研究和应用

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1 873 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.120 t 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0.001 0％时,每炉钢水喂纯钙线150 m(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.