浸入式水口结构对180 mm×240 mm断面连铸结晶器内钢液流动行为的影响  

Effect of submerged nozzle geometry on flow behavior for 180 mm × 240 mm billet continuous casting mold

作　　者：吴光辉[1] 唐海燕[1] 程鹏飞[1] 郭晓晨[1] 张家泉[1] 甄先锋 张海涛 王时松 WU Guanghui TANG Haiyan CHENG Pengfei GUO Xiaochen ZHANG Jiaquan ZHEN Xianfeng ZHANG Haitao WANG Shisong(School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China Qingdao Iron and Steel Group Company, Qingdao 266000, China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]青岛钢铁集团公司,山东青岛266000

出　　处：《炼钢》2017年第4期31-38,45,共9页Steelmaking

基　　金：北京科技大学校企合作项目(2014-715);北京科技大学本科生教研基金(JG2014M08)

摘　　要：为改善国内某钢厂高碳硬线钢铸坯的内部质量,以实际180 mm×240 mm方坯连铸结晶器为原型,基于相似原理,采用1∶1的物理模型,对比研究了直通型和侧分旋流型水口浇铸条件下的结晶器内流体流动行为。试验测定了不同拉速和水口浸入深度下结晶器内钢液的流股分布、液面波动及渣层状态。结果表明:旋流水口可有效降低流股冲击深度;相同水口浸入深度和拉速条件下,使用旋流水口的结晶器液面平均波高大于直通型水口;拉速和浸入深度对旋流型水口的液面波动影响明显,渣层波动也比直通型水口频繁。综合液面波动和渣层状态并考虑成本因素,旋流水口更适合浇铸该断面高品质铸坯,其适宜的工艺参数为拉速1.0 m/min、浸入深度120 mm,此时自由液面平均波高0.18 mm,渣层波动适宜,无卷渣和裸钢现象发生。将该水口配合结晶器电磁搅拌和二冷工艺应用于高碳硬线钢生产,得到的铸坯质量稳定,Φ5.5 mm盘条中心碳偏析不大于2.0级的比例达95%以上,疏松缩孔不大于0.5级的比例达100%。To improve the internal quality of high carbon wire steel produced by a domestic steel factory,the fluid flow behavior in a 180 mm × 240 mm billet continuous casting mould was investigated with 1 ∶ 1water model,based on the similarity principle. The distribution of the molten steel,the fluctuation of the mold liquid surface and the state of the slag layer using single-port straight nozzle and four-port swirling nozzle were compared by the experiment. The results show that using swirling nozzle can effectively decrease the impact depth of fluid; the average fluctuation height of swirling nozzle is larger than the straight one at the same immersion depth and casting speed. In addition,casting speed and immersion depth affect the fluctuation of mold liquid surface of swirling nozzle more obviously,and the fluctuation of slag layer is more frequent for the swirling nozzle than for the straight one. Considering the fluctuation of the mold liquid surface,the state of the slag layer and cost,the swirling nozzle is more fit for casting the high quality billet in this section,and the optimum process is at the casting speed 1. 0 m/min and the immersion depth 120 mm with the average wave height of free surface at 0. 18 mm. In this case,the slag layer fluctuates properly,and no slag is entrapped and molten steel exposed. The billet of high carbon steel produced by using this nozzle combining with mold-EMS and secondary cooling has stable quality; over 95% of wire rods in diameter 5. 5 mm possess center carbon segregation level below 2. 0 grade,and the porosity and shrinkage levels of all wire rods are below 0. 5 grade.

关 键 词：方坯结晶器 旋流水口 直通水口 液面波动 卷渣 

分 类 号：TF777.1[冶金工程—钢铁冶金]