单水口浇注Q420NQR1异型坯表面纵裂纹控制  

Control of Longitudinal Crack on Surface of Q420NQR1 BeamBlank with Single Nozzle Pouring

作　　者：张凯 彭治强 卢雄慧 赵宏志 崔弘[1] 侯自兵[2] 唐萍[2] Zhang Kai;Peng Zhi-qiang;Lu Xiong-hui;Zhao Hong-zhi;Cui Hong;Hou Zi-bing;Tang Ping(Steel-making Plant of Inner Mongolia Baotou Steel Union Co.,Ltd.,Baotou 014010,Inner Mongolia Autonomous Region,China;School of Materials Science and Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]内蒙古包钢钢联股份有限公司炼钢厂,内蒙古包头014010 [2]重庆大学材料科学与工程学院,重庆400044

出　　处：《包钢科技》2023年第6期7-12,共6页Science & Technology of Baotou Steel

摘　　要：针对亚包晶钢Q420NQR1连铸坯及轧材的表面纵裂纹缺陷分析了纵裂纹成因并提出了控制措施。结果表明,轧材的纵裂纹缺陷源于铸坯表面纵裂纹,铸坯表面纵裂纹绝大部分位于异型坯远离水口位置的腹板。通过物理模拟对结晶器内部流场进行研究,发现结晶器内腹板位置存在单循环流,这直接导致远离水口位置的保护渣液渣层较薄,在该位置下难以实现有效控热。通过适当增加水口插入深度可以降低钢液表面流速并促进液渣均匀分布;同时结合保护渣非均匀布料方式可有效改善铸坯及轧材质量,铸坯及轧材纵裂纹率分别降低30%和34%。In this paper,the causes of defect of longitudinal crack on surface of Q420NQR1 continuous casting billet and rolled products with hypo-peritectic steel are analyzed as well as the control measures are put forward.The results indicated that the defect of longitudinal cracks for rolled products originated from longitudinal cracks on surface of casting blank,most of which were on the web of beam blank away from submerged entry nozzle.The inner flow field of crystallizer is studied by physical simulation.It is found that there is single circulation flow on the web of crystallizer,which directly causes the melt cinder layer of casting powder away from submerged entry nozzle to be thinner so that effective heat control is difficult to be realized at this position.The flow velocity of surface layer of liquid steel could be reduced and even distribution of melt cinder could be promoted through appropriately increasing the insertion depth of submerged entry nozzle;the quality of casting blank and rolled products could be improved combining with the uneven burden distribution mode of casting powder so that the longitudinal crack rates of casting blank and rolled products are reduced by 30%and 34%respectively.

关 键 词：Q420NQR1异型坯 纵裂纹 物理模拟 插入深度 非均匀布料 

分 类 号：TF777[冶金工程—钢铁冶金]