大圆坯连铸延迟封顶收尾坯工艺的开发和应用  

Development and Application of Capping Delayed Running Out Process for Large Round Bloom Continuous Casting

作　　者：陈远清[1,2] 仇圣桃 刘和平[1] 李尚兵[2] 仇灏 Chen Yuanqing;Qiu Shengtao;Liu Heping;Li Shangbing;Qiu Hao(National Engineering and Research Center for Continuous Casting Technology,Central Iron and Steel Research Institute,Beijing 100081,China;Zhangjiagang Lianfeng Iron&Steel Research Institute Co.Ltd.,Zhangjiagang 215628,Jiangsu,China)

机构地区：[1]钢铁研究总院连铸技术国家工程研究中心,北京100081 [2]张家港联峰钢铁研究所有限公司,江苏张家港215628

出　　处：《钢铁钒钛》2019年第5期143-149,共7页Iron Steel Vanadium Titanium

摘　　要：对比分析了?380~?800 mm大圆坯连铸尾坯的凝固组织、低倍质量与正常坯的差异;发现尾坯存在等轴晶比例低、白亮带比例高、中心缩孔和疏松级别高等问题。基于收尾坯工艺,理论分析了其产生原因,并提出了一种延迟封顶收尾坯工艺来改善尾坯质量。工业试验结果表明:延迟封顶收尾坯工艺通过在钢液面加入发热剂并按顺序关闭各段二冷水,延迟了封顶的时间,有效增加了熔池的补缩效果;在切尾长度减小0.5 m时尾坯低倍不合格比例由6.25%降低到1.96%,钢水收得率平均提高0.55%。The difference of solidification structure and macro quality between trail bloom and normal bloom has been comparatively analyzed for ?380~ ?800 mm large round bloom.Some defects such as low ratio of equiaxed crystal zone,high ratio of white band,serious central porosity,cavity and crack are observed in the trail bloom.The causes have been theoretically analyzed based on running out process,and a capping delayed running out process has been put forward to improve the trail bloom quality.Industrial test result shows that the capping delayed running out process can delay the strand capping by adding some heating agent on the top surface and switching off the spraying water in order,which leads to more sufficient contraction compensation.Thus,unqualified ratio of trail bloom decreases from 6.25%to 1.96%when tail cropping length is reduced by 0.5 m,and the liquid steel yield is improved by 0.55%.

关 键 词：连铸 大圆坯 收尾坯 内部缺陷 发热剂 封顶 

分 类 号：TF777[冶金工程—钢铁冶金]