低碳铝镇静钢铸坯皮下钩状坯壳  

Investigation of subsurface hooks in continuous cast low carbon aluminum-killed steel slab

作　　者：苑鹏[1,2] 邓小旋[2] 姜敏[1] 王新华[1] 冀云卿[1] 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]首钢集团总公司首钢技术研究院,北京100041

出　　处：《钢铁》2015年第8期24-33,共10页Iron and Steel

摘　　要：低碳铝镇静钢铸坯皮下有明显的钩状坯壳,钩状坯壳很容易捕获夹杂物和气泡,使得簇群状氧化铝夹杂和气泡+氧化铝在铸坯的近表层聚集。对低碳铝镇静钢铸坯的宽面、窄面以及角部综合取样,研究分析了铸坯不同位置处钩状坯壳的特征与变化规律。结果显示,在铸坯宽面,中心处钩状坯壳较深;在铸坯窄面,越靠近角部,钩状坯壳越深;在铸坯角部,钩状坯壳呈现三维形貌。此外,提出了钩状坯壳对夹杂物和气泡的捕获机理,认为连铸过程中的Marangoni力对夹杂物和气泡的捕获起着至关重要的作用。此机理很好地解释了钩状坯壳更易捕获大尺寸夹杂物和气泡的原因;根据该机理,提出了减小钩状坯壳捕获大尺寸夹杂物的相关措施。A distinctive microstructural feature called a ＂hook＂is often observed on the subsurface of low carbon aluminum-killed steel slabs during continuous casting processes. Inclusions and bubbles are easy to be entrapped by the hooks,which makes Al2O3 cluster and ＂Ar ＋ Al2O3＂type inclusions gathered in subsurface layer of the slabs. A large number of samples were obtained from wide face,narrow face,and corner of the slab in this experiment. The characteristics of hooks in different positions of the slab were investigated. The results showed that in the wide face the center of hooks are deeper than others,in the narrow face the hook depth increase when close to the corner of slab,and hooks near the corners of the slab exhibited three-dimensional morphology. Furthermore,a mechanism of hooks entrapping alumina inclusions and argon bubbles was proposed,which suggested that marangoni force in the process of continuous casting plays an important role on the entrapment of alumina inclusions and argon bubbles. By investigating the behavior of inclusions and bubbles in solidification front of hooks,this mechanism explained the process of how hooks entrapping large side inclusions and bubbles well. From the result,the countermeasure of reduction of hooks and inclusions was proposed.

关 键 词：连铸 钩状坯壳 低碳铝镇静钢 非金属夹杂物 气泡 表面张力梯度 

分 类 号：TF777[冶金工程—钢铁冶金]