100 t复吹转炉-RH-70 mm板坯连铸流程0. 88% Si无取向硅钢的夹杂物行为

0.88%Si无取向硅钢的生产工艺为100 t BOF出钢时加300kg石灰,终点C]0.035%~0.05%,出钢温度1640~1650℃,RH吹氧脱碳,加99.0%Al-Fe合金6.69 kg/t,加70%Si-Fe合金15.70 kg/t,70 mm板坯连铸过程全程保护浇铸,使用镁质碱性中间包覆盖剂。分析结果表明,RH终点O]28×10^-6,铸坯O]22×10^-6,RH-前N]为16×10^-6,RH过程增氮4×10^-6,RH结束到铸坯增氮6×10^-6;RH脱碳终点时钢中夹杂物以球形MnO·Al₂O₃为主;RH出站时以不规则形状的Al₂O₃为主,并伴有少量单独存在的CaS夹杂;中间包钢液内的夹杂物主要以不规则形状的Al₂O₃为主;铸坯中多为不规则形状的Al₂O₃以及少量AlN,还有少量由结晶器卷渣引起的含Na成分的复合夹杂物。

Behavior of Inclusions in 0.88% Si Non-Oriented Silicon Steel Steelmaking by Process of 100 t Combined Blowing Converter-RH-70 mm Slab Flowsheet

The production process of 0. 88% Si non-oriented silicon steel is adding 300 kg lime in tapping of 100 t BOF, controlling end C] 0.035%-0.05% and tapping liquid temperature 1640-1650 °C , RH blowing oxygen to decarburize ,adding 99.0% Al-Fe alloy 6.69 kg/t and adding 70%Si-Fe alloy 15.70 kg/t in RH refining process, in whole process shield-atmosphere casting 70 mm slab, and using magnesia basic tundish shielding agent. Analysis results show that RH end O] is 28 x 10^-6, slab O] is 22 x 10^-6 , RH beginning N] is 16 x 10^-6, nitrogen content in liquid increases by 4 x 10^-6 during RH process and the nitrogen content in steel increases by 6 x 10^-6 during end RH to slab casting process ； at end RH decarburization the main inclusions in steel are spherical MnO·Al₂O₃, after RH Refining the main inclusions in steel are irregular Al₂O₃ accompanied by a small amount CaS inclusions ； the main inclusions in liquid of tundish are irregular Al₂O₃ ； in casting slab the most inclusions are irregular Al₂O₃ with a small amount of AIN and minor composite inclusions containing Na caused by slag enclosure in mold.