摘要
某钢厂通过连铸工艺生产齿轮钢20CrMnTi大方坯,其产品整体指标达到了优质齿轮钢的水平,但存在产品质量不稳定的问题。本文采用气体分析法和化学分析法对比研究了换包过程中钢中全氧、氮含量和酸溶铝含量的变化规律,采用扫描电镜和能谱分析的方法研究了大型夹杂物和显微夹杂物的主要类型和特征。结果表明,在换包过程中,中间包内钢液的全氧含量和氮含量均高于VD精炼结束后的水平;换包时[Als]含量平均比稳态浇注时低10%,后续会导致换包过程中铸坯的洁净度也相对较差。齿轮钢中的显微夹杂物主要为A类夹杂物、T类夹杂物和各类Ca-Si-Mg-Al系复合夹杂物。换包过程中大型夹杂物的量明显高于稳态浇注铸坯,大型夹杂物呈近球形或不规则形状,可能来源于卷渣和耐材的侵蚀等。
20 CrMnTi gear steel billet is produced through continuous casting process in a steelmaking plant, and the overall quality reaches the high level, but the quality is unstable. In this paper, the content of T.O, [N] and [Als] was measured by gas analysis and chemical analysis, and the main types and characteristics of inclusions were studied by SEM and EDS. The results showed that the T.O and [N] of molten steel in tundish were higher than those after VD refining. The content of [Als] during ladle changing was around 10% lower on average than that in steady-state casting, resulting in relatively poor cleanliness of the subsequent casting billet during ladle changing. The micro-inclusions in gear steel were mainly type A inclusions, type T inclusions and various kinds of Ca-Si-Mg-Al composite inclusions. Meanwhile, the amount of large inclusions during ladle change was obviously higher than that of steady casting billet, and the large inclusions were of near-spherical or irregular shape, which may be caused by slag entrapment and refractory erosion.
作者
李权辉
张江山
高江
邵鑫
陶镳
刘青
LI Quanhui;ZHANG Jiangshan;GAO Jiang;SHAO Xin;TAO Biao;LIU Qing(Nanjing lron&Steel Co.,LTD.,Nanjing 210044,China;University of Science and Technology Beiing,Beijing 100083,China)
出处
《金属材料与冶金工程》
CAS
2020年第6期39-45,50,共8页
Metal Materials and Metallurgy Engineering
基金
国家自然科学基金项目(52004024)
中央高校基本科研业务费资助项目(FRF-TP-19-678AL)
中国博士后科学基金资助项目(2019M660460)。
关键词
齿轮钢
换包
连铸
洁净
gear steel
ladle change
continuous casting
cleanness
