Abstract: The flowsheet for steel SPHC (/% : ≤0.08C, ≤0. 05Si, 0. 10 ~0. 30Mn, ≤0, 025P, ≤0.025S, 0. 020 ~0. 045Al) is hot metal pretreatment- 150 t top and bottom combined blown converter- LF- double strand slab casting process- 1 780 mm hot continuous rolling process. By analysis on nozzle blocking substance it is obtained that the main ingredient of blocking substance is Al₂O₃ and high melting point (1 750 ℃ ) CaO·2Al₂O₃ inclusion, the outlet of blocking substance is piled up alumina with loose structure, the middle layer is net type alumina and the inner layer is decarburized zone of nozzle materials. With the process measures including controlling converter end [C] > 0. 04% , adjusting feeding calcium wire amount to increase the liquid average calcium-aluminium ratio from 0. 03 to 0. 06, increasing soft argon blowing time from 6 ~ 8 min to 8 ~ 10 min and preventing liquid secondary oxidizing in casting process, the results of 48 heats steel SPHC production show that the nozzle blocking accidents are averted.

摘要： SPHC钢（/%:≤0.08C,≤0.05Si,0.10~0.30Mn,≤0.025P,≤0.025S,0.020~0.045Al）的工艺流程为铁水预处理-150 t顶底复吹转炉-LF-双流板坯连铸-1780 mm热连轧工艺。通过水口结瘤物分析得出,水口结瘤物主要成分为Al₂O₃和高熔点（1750℃）CaO·2Al₂O₃夹杂,结瘤物外层为结构疏松的堆积状氧化铝层,中间层为网状氧化铝层,内层为水口材料的脱碳层。通过控制转炉终点[C]>0.04%,调整喂钙铁线用量,使钢液中平均钙铝比由0.03提高至0.06,精炼时软吹氩搅拌由6~8 min提高到8~10 min,连铸过程防止钢液二次氧化等工艺措施,48炉SPHC钢生产结果表明,避免了水口结瘤事故的发生。

关键词: SPHC钢, 浸入式水口结瘤, Al₂O₃夹杂物, 钙处理, 工艺改善