Abstract: Flow sheet for X80 pipeline steel (basic composition /%: 0. 09C, 0. 42Si, 1. 85Mn, 0. 022P, 0. 005S, 0. 06Als) is KR metal desulphurization pretreatment-300 t top and bottom combined blowing converter-ladle argon blowing- LF-RH-250 mm x 2 150 mm slab casting process. The main steelmaking and refining optimizing processes are controlling converter tapping slag amount ≤4 kg/t, using (%) 55 ~60CaO, 7 ~ 12SiO3, 25 - 30Al₂O₃ refining slag series to control LF refining slag CaO/Al₂O₃ = 1.7 ~ 1. 9, CaO/SiO₂ 二 4. 5 ~ 6. 0 and ( FeO + MnO)≤ 1. 0%, pre-forming slag at ladle argon blowing station with top and bottom argon blowing, RH vacuum ≤66. 7 Pa and feeding 0. 8 kg/t calcium wire after RH treatment. Results show that carbon-oxygen product-[C] [0] at converter endpoint decreases to 0. 002 44 from original 0. 002 84, after refining ( FeO + MnO) is 0. 913%, T [0] is 0. 001 3% and rating of inclusions in products is 1. 0.

摘要： X80管线钢(基本成分/%:0.09C、0.42Si、1.85Mn、0.022P、0.005S、0.06Als)的冶金流程为KR铁水脱硫预处理-300 t顶底复吹转炉-钢包吹氩-LF-RH-250 mm×2 150 mm板坯连铸。工艺炼钢和精炼主要优化工艺为:控制转炉出钢下渣量≤4 kg/t,采用(%):55～60CaO、7～12SiO2、25～30Al₂O₃精炼渣系,控制LF精炼渣CaO/Al₂O₃=1.7～1.9,CaO/SiO₂=4.5～6.0,(FeO+MnO)≤1.0%,吹氩站顶底吹氩预成渣,RH真空度≤66.7 Pa,RH后喂钙线0.8 kg/t。结果表明,转炉终点碳氧积由0.002 84降为0.002 44;精炼后(FeO+MnO)为0.913%,全氧含量为0.0013%。成品材夹杂物级别≤1.0。