非钙处理铝脱氧车轮钢夹杂物形成及变形行为  

Inclusion formation and deformation in Al-killed wheel steel without calcium treatment

作　　者：赵东伟[1] 李海波[1] 高攀[1] 杨健[2] 郝丽霞[2] 

机构地区：[1]首钢技术研究院薄板所,北京100043 [2]首钢股份公司迁安钢铁公司,河北迁安064404

出　　处：《钢铁》2016年第1期25-32,共8页Iron and Steel

摘　　要：通过采用扫描电镜对BOF-LF-RH-CC非钙处理工艺生产车轮钢系统取样样品中夹杂物的形貌、尺寸及组成的分析,研究了精炼和凝固过程氧化物夹杂的形成、上浮去除和析出过程,以及轧制过程夹杂物的变形行为。研究发现,在非钙处理条件下,LF精炼过程会形成大量MgO-Al_2O_3夹杂和CaO-Al_2O_3夹杂,并且在RH精炼过程中存在MgO-Al_2O_3夹杂向CaO-Al_2O_3夹杂的转变过程,最终导致铸坯中出现低变性CaO-Al_2O_3夹杂;在软吹和镇静过程中,炉渣或空气对钢液的二次氧化与钢液中夹杂物上浮去除存在动态平衡;在钢液凝固过程中,固液界面的Al_2O_3等氧化物夹杂为MnS的析出提供了异质形核点,形成半包裹状的Al_2O_3-MnS类复合夹杂物;在轧制过程中,团簇状Al_2O_3夹杂容易被轧碎在板卷中形成点链状,高熔点半包裹的Al_2O_3-MnS类复合夹杂物被轧制成小尾巴状,而低熔点的CaOAl_2O_3-MnS的复合夹杂形成连续的条状。The formation and deformation mechanism of oxygen inclusions in Al-killed wheel steel without calcium treat- ment were studied by industrial trials based on systematic sampling and electron microscopy analysis on inclusions mor- phology, size and composition. It can be found that, under the condition of no calcium treatment, massive MgO-AI2O3 in- clusions and CaO-AI2O3 inclusions were formed during LF refining and there was a transformation process from MgO- AI2O3 inclusions to CaO-AI2O3 inclusions during RH refining, which leads to generate massive low-modified CaO-AI2O3 inclusions in slab.： During the process of soft bottom stirring and holding process, there can exist a dynamic equilibrium between reoxidation of molten steel by slag or air and flotation removal of inclusions in ladle; During solidification pro- cess, ALO3 based inclusions surrounding a little MnS were formed because AI2O3 based inclusions provided the position of heterogeneous nucleation of MnS precipitation in the interface of solid and liquid during solidification, which made MnS easier precipitate on the surface of AI2O3 based oxygen inclusions. During hot rolling process, alumina inclusions of clusters were often deformed to chain-like ones, AI2O3 based inclusions surrounding a little MnS to tiny tail-like ones, and low-temperature point CaO-AI2O3 inclusions to long striped ones.

关 键 词：铝镇静钢 车轮钢 非钙处理 夹杂物 变形 

分 类 号：TF76[冶金工程—钢铁冶金]