100 t EAF-LF-VD-圆坯连铸流程生产石油钻铤用钢 AISI4145HM 的工艺实践

莱钢特钢事业部新区采用铁水+废钢-100 t电弧炉-LF-VD-Φ500,600 mm圆坯连铸-步进式加热炉-950轧机轧制-缓冷-退火的流程生产Φ110～260 mm AISI4145HM钢（/%:0.44～0.46C,0.21～0.23Si,1.32～1.33Mn,1.18～1.20Cr,0.30～0.31Mo,0.16～0.17Ni,≤0.012P,≤0.004S,≤0.05Cu,0.15～0.35Alt）。通过控制电弧炉终点C]≥0.15%,P]≤0.008%,出钢预脱氧和合金化,LF高铝精炼渣（30%～40%Al₂O₃）及喂0.45kg/t钢钙线,VD后梯度软吹,控制中间包钢水过热度12～25℃,拉速0.25～0.35 m/min,全程保护浇铸及M-EMS和F-EMS,轧后缓冷、退火等工艺措施,生产的铸坯低倍组织良好,中心疏松和中心缩孔≤1.0级,裂纹和皮下气泡为0级,各类夹杂物级别≤1.5,级别总和≤7.0,钢的各项指标均满足协议要求。

Practice of Commercial Production of Steel AISI4145HM for Petroleum Dill by 100 t EAF-LF-VD Round Bloom CC Flowsheet

The Φ 110 ?260 mm products of steel AISI4145HM (/% : 0.44 -0.46C, 0. 21 ?0. 23Si, 1. 32 ~ 1.33Mn, 1. 18-1.20Cr, 0. 30 ~0. 31 Mo, 0.16 ~0.17Ni, ≤ 0.012P, ≤ 0.004S, ≤ 0.05Cu, 0. 15 ~0. 35Als) is produced by hot-metal + scrap- 100 t EAF-LF-VD-0500, 600 mm round bloom casting-walking beam reheating furnace- 950mm rolling mill- slow cooling- annealing flowsheet, in the special steel division new district of Laiwu steel. With the process measures including controlling EAF end C]≥0.15% and P]≤0.008% , pre-deoxidation and alloying in tapping, using LF high aluminium refining slag (30% ~40% Al₂O₃) and feeding 0. 45 kg/t calcium wire, gradient soft blowing after VD, controlling overheating extent of liquid in tundish 12 - 25℃ ，casting speed 0. 25 ?0. 35 m/min, whole course shielding casting, using M-EMS and F-EMS, slow cooling after rolling and annealing, the macro structure of produced casting bloom is better with center porosity and center line shrinkage ≤ rating 1.0, crack and subskin blowhole rating 0, each inclusion rating ≤ 1. 5, total inclusions rating ≤ 7. 0, the each index of steel products all meets the requirement of specification.