Abstract: The Q195 steel is produced by M120 t BOF→LF→Ca addition→160 mm x 160 mm CC” process. It was found by tracing test that the number of ≥27μm large size inclusions at test area 50 x 400 mm² in the billet is 31 and generated by LF top slag entrapped during gas stirring, calcium treatment formed CaS, submerged entry nozzle material stripped and formed endogenous large size calcium-aluminate inclusion in steel as the flow rate of argon is in the range of 300～600 L/min. The proportion of LF top slag entrapped is about 29. 1% in all the large size inclusions. As the flow rate of argon decreases from 300～600 L/min to 100 L/min, it is found that the LF top slag entrapped could be significantly decreased ,at some test area the ≥27μm inclusions number decreases to 19.

摘要： 采用"120 t BOF→LF→Ca处理→160 mm × 160 mm CC"工艺生产的Q195钢。示踪检验得出,当LF精炼过程氩气流量在300～600 L/min时,50 × 400 mm²检验面积中,铸坯中≥27 μm大尺寸夹杂物31个,主要来源于LF精炼渣卷渣、钙处理生成的CaS、水口内壁材质剥落和钢中内生大尺寸钙铝酸盐夹杂物,其中由LF精炼渣卷渣形成的大尺寸夹杂物所占比例为29.1%。通过精炼全程将氩气流量由300～600 L/min降低至100 L/min,发现可以显著降低精炼渣卷渣形成的大尺寸夹杂物数量,同样的检测面积≥27 μm夹杂物降至19个。

关键词: 120 t LF, 大尺寸夹杂物, 精炼渣卷渣, 氩气搅拌强度