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

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

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%Al_2O_3)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。

The Φ110～260 mm products of steel AISI4145 HM（/% ： 0. 44 ～0. 46 C,0. 21 ～ 0. 23 Si, 1. 32 ～1.33 Mn, 1. 18～1.20 Cr,0.30～0.31 Mo,0.16～0.17 Ni,≤0.012 P,≤0.004 S,≤0.05 Cu, 0. 15 ～0.35 Als） is produced by hot-metal ＋ scrap-100 t EAF-LF-VD-Φ500, 600 mm round bloom casting-walking beam reheating furnace-950 mm 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% Al2 O3） 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.