Q235方坯非金属夹杂物行为研究

Research on Non-metallic Inclusions Behavior in Continuous Casting Square Billet of Q235 Steel

基于夹杂物示踪剂法对国内某厂Q235B钢转炉—连铸生产工艺的各个环节展开了系统的研究和分析。结果表明:铸坯中夹杂物水平较高,二次氧化严重。其中显微夹杂物为Si O2-Mn O-Mn S、Si O2-Mn O-Mo O3等复合夹杂,未发现Ce、La等示踪元素;大型夹杂物中则普遍含有Ce、La、K、Na等示踪元素,说明其主要源于中间包覆盖剂,保护渣和钢包渣的卷入。大型夹杂物危害极大,需要从中间包、浸入式水口等反应器针对性的结构优化,冶炼浇铸工艺的稳定化和冶金辅料的性能优化三方面共同着手来实现大型夹杂物的去除。

Based on the inclusion tracer method,all aspects of the converter-continuous casting process adopted by iron and steel enterprises during produced Q235 B steel production had been researched systematically. The results show that strand has high inclusion content level and strong reoxidation. Microscopic inclusions mainly consist of Si O2-Mn O-Mn S,Si O2-Mn O-Mo O3 composite and no Ce and La has been measured,however,tracers of Ce,La,K,Na have been found in most of macro inclusion,which implies that macro inclusions mainly come from the tundish covering flux,mould flux and ladle slag. For reducing the big inclusion content which has the worst effect on the steel quality,the structure of the tundish and the submerged entry nozzle should be optimized,the casting technology should be more stable,at the same time the met allurgical properties of the supplementary material should be optimized to fit for the current casting.