100t BOF-CAS-RH-230mm板坯连铸流程2.66%Si无取向电工钢50W350夹杂物分析  

Analysis on Inclusions of 2.66%Si Non-Oriented Electrical Steel 50W350 in 100 t BOF-CAS-RH-230 mm Slab Casting Flowsheet

作　　者：盛鹏飞[1,2] 项利[2] 仇圣桃[2] 

机构地区：[1]安徽工业大学冶金工程学院,马鞍山243002 [2]钢铁研究总院连铸技术国家工程研究中心,北京100081

出　　处：《特殊钢》2017年第3期9-13,共5页Special Steel

摘　　要：试验50W350无取向电工钢(/%:0.002C,2.66Si,0.25Mn,0.012P,0.002S,0.760Als,0.762Alt)的生产工艺为铁水预处理,100 tBOF出钢加300 kg石灰,终点[C]≤0.05%,出钢温度1 640~1 650℃,CAS处理5 min,RH吹氧脱碳,加99.0%Al-Fe合金6.69 kg/t,70%Si-Fe合金15.7 kg/t,230 mm板坯连铸过程全程保护浇铸,采用无碳专用碱性覆盖剂。分析结果表明,钢中夹杂物的数量从CAS处理结束后的306.26个/mm^2降至连铸坯中145.12个/mm^2,夹杂物尺寸在≤3μm占总量的90%以上;冶炼过程中夹杂物主要为高铝质夹杂,部分Al_2O_3单独存在于氩处理结束和钢包的钢中,中间包和铸坯中的Al_2O_3与其他夹杂物结合,以复合夹杂物的形式存在于钢中,此外钢包和铸坯中还发现了AlN夹杂;铸坯中大型夹杂物总量为6.20 mg/10 kg,140~300μm夹杂约占大型夹杂总量的60%,同时存在少量含Na、K的大型非金属夹杂物。The production process of tested non-oriented electrical steel 50W350 （/% ： 0. 002C, 2. 66Si, 0. 25Mn, 0. 012P, O. 002S, O. 760Als, 0. 762Ah） is hot-metal pretreatment, adding 300 kg lime in tapping of an 100 t BOF, con- trolling end [ C] 〈0. 05% and tapping liquid temperature 1 640 - 1 650, CAS treating for 5 min, RH blowing oxygen to decarburize, adding 99.0% A1-Fe alloy 6. 69 kg/t and 70% Si-Fe alloy 15.7 kg/t in RH refining process, in whole process shielding-atmosphere casting 230 mm slab, and using special carbon-free basic shielding agent. Analysis results show that at end CAS treatment the number of inclusions in steel is 306. 26 piece/mm2, in cast slab that decreases to 145.12 piece/ mm2 and the ~〈3 tLm inclusions make up more than 90 percent of the total amount of inclusions; in steelmaking process the main inclusions are high-aluminum inclusions, some single A12 03 inclusions exist in liquid at end argon blowing and in la- dle, in tundish and cast slab the A1203 combines with other inclusions to form complex inclusions in steel; besides the A1N inclusions are found in liquid in ladle and in cast slab ; the total amount of large scale inclusions in cast slab is 6. 20 mg/10 kg, the 140 -300 m inclusions make up about 60 percent of total large scale inclusions, and a small amount of large scale inclusions containinz Na and K exists in slab.

关 键 词：100 t BOF—CAS—RH-230 mm板坯连铸无取向电工钢50W350夹杂物 

分 类 号：TF777.1[冶金工程—钢铁冶金]