关键词: 120 t LF, 大尺寸夹杂物, 精炼渣卷渣, 氩气搅拌强度

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.