Abstract: The production process of tested non-oriented electrical steel 50W350 (/%: 0.002C, 2.66Si, 0.25Mn, 0.012P, 0.002S, 0.760Als, 0.762Alt) is hot-metal pretreatment, adding 300kg lime in tapping of an 100t BOF, controlling end [C]≤0.05% and tapping liquid temperature 1640〜1650℃ , CAS treating for 5min, RH blowing oxygen to decarburize, adding 99.0% Al-Fe alloy 6.69kg/t and 70% Si-Fe alloy 15.7kg/t in RH refining process, in whole process shielding-atmosphere casting 230mm 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 ≤3μm 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 Al₂O₃ inclusions exist in liquid at end argon blowing and in ladle ,in tundish and cast slab the Al₂O₃ combines with other inclusions to form complex inclusions in steel；besides the AIN inclusions are found in liquid in ladle and in cast slab； the total amount of large scale inclusions in cast slab is 6.20mg/10kg, the 140〜300μm inclusions make up about 60 percent of total large scale inclusions, and a small amount of large scale inclusions containing Na and K exists in slab.

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,100tBOF出钢加300kg石灰,终点[C]≤0.05%,出钢温度1640~1650℃,CAS处理5min,RH吹氧脱碳,加99.0%Al-Fe合金6.69kg/t,70%Si-Fe合金15.7kg/t,230mm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/mm²降至连铸坯中145.12个/mm²,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Al₂O₃单独存在于氩处理结束和钢包的钢中,中间包和铸坯中的Al₂O₃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6.2 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。

关键词: 100tBOF-CAS-RH-230mm板坯连铸, 无取向电工钢50W350, 夹杂物