Mechanism of Non-metallic Inclusion Formation and Modification and Their Deformation during Compact Strip Production (CSP) Process for Aluminum-Killed Steel
Mechanism of Non-metallic Inclusion Formation and Modification and Their Deformation during Compact Strip Production (CSP) Process for Aluminum-Killed Steel
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DOI：
10.2355/isijinternational.53.2142
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发表时间：
2013-12
影响因子：
1.8
通讯作者：
G. Jing;Cheng Shu-sen;Chen Zi-jian
中科院分区：
文献类型：
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作者：
G. Jing;Cheng Shu-sen;Chen Zi-jian
通过工业试验研究了铝镇静钢连铸连轧工艺（CSP工艺）中非金属夹杂物的形成与变质。借助计算软件FactSage，对Al2O3、MgO·Al2O3尖晶石、各种铝酸钙和CaS夹杂物形成的热力学进行了分析。研究发现，LF（钢包炉）精炼过程中钢液中的氧活度是由夹杂物中溶解的Al和Al2O3之间的平衡决定的。 LF精炼时Al2O3夹杂物改性有两种方式：第一种路线为Al2O3-低改性铝酸钙-液体铝酸钙；另一种为Al2O3-MgO·Al2O3尖晶石-CaO-MgO-Al2O3多元夹杂物。此外，液体铝酸钙具有多组分夹杂物的倾向。在凝固过程中，板坯中可能会析出两种类型的 CaS 夹杂物。有利的改性夹杂物在轧制过程中与钢基体一起变形得很好，即使它们与CaS承载层相关，而无或低改性Al2O3基夹杂物会被轧成碎片，并且可能在夹杂物周围产生微裂纹。
The formation and modification of non-metallic inclusions for Al-killed steel during Compact Strip Production Process (CSP Process) was studied by industrial experiments. The thermodynamics for the formation of Al2O3, MgO·Al2O3 spinel, various calcium aluminates and CaS bearing inclusion were analyzed with the help of calculation software FactSage. It is found that the oxygen activity in liquid steel during LF (Ladle Furnace) refining is confirmed to be determined by the equilibrium between dissolved Al and Al2O3 in inclusion. There are two manners for Al2O3 inclusion modification during LF refining: the first route is followed by Al2O3-low modified calcium aluminates-liquid calcium aluminates; and the other is as Al2O3– MgO·Al2O3 spinel-CaO–MgO–Al2O3 multi-component inclusion. In addition, the liquid calcium aluminates have the tendency to be multi-component inclusion. Two types of CaS bearing inclusion could precipitate in a slab during solidification. The favorable modified inclusions deform very well along with steel matrix during rolling process even if they are associated with CaS bearing layer, while the no or low modified Al2O3 based inclusion would be rolled into pieces and the micro-cracks might be generated around the inclusions.