Q355BS中厚板皮下气泡缺陷的原因分析与解决

Cause Analysis and Solution of Subcutaneous Bubble Defect of the Medium and Heavy Plate Q355BS

为了解决Q355BS中厚板皮下气泡质量缺陷,使用金相显微镜对钢板上的气泡缺陷进行了观察,使用LECO氧氮氢气体分析仪检测了缺陷钢板中[O]、[N]、[H]的质量分数,使用ARL8820直读光谱仪检测试样的化学成分,通过加强钢水脱氧,减少LF精炼过程中萤石的使用量,降低结晶器保护渣中氟的质量分数,解决了Q355BS板坯气泡缺陷质量问题。结果表明:当钢中的Als质量分数≥0.0040%,吨钢萤石用量<1.5 kg,结晶器保护渣中氟的质量分数<6.5%时,Q355BS板坯发生皮下气泡缺陷的可能性低。

In order to solve the subcutaneous bubble defect of the medium and heavy plate Q355BS,metallographic microscopy is used to detect the sample wich defect of subcutaneous bubble,LECO oxygen、nirtrogen and hydrogen gas analyzer is used to detect the mass fraction of oxygen、nirtrogen and hydrogen in the plate Q355BS,ARL8820 Direct-reading spectrometer is used to detect the mass fraction of chemical composition in the plate Q355BS,oxygen in the liquid steel is removed deeply,reduce the use of fluorite in the refining process of ladle furnace,reduce the mass fraction of fluorine in the mould powder,the subcutaneous bubble defect of the medium and heavy plate Q355BS was solved.The results show that:the possibility of subcutaneous bubble defect of the medium and heavy plate Q355BS is low,when the mass fraction of Als in the steel greater than 0.0040%,the amount of fluorite used in the refining process per tone less than 1.5kg,the mass fraction of fluorine in the mould powder less than 6.5%.