合金钢精炼过程中夹杂物演变行为研究.docVIP

 合金钢精炼过程中夹杂物演变行为研究# 李刚，李京社，马昱，孙丽媛* （北京科技大学冶金与生态工程学院，北京 100083） 5 10 15 20 25 摘要：研究了 90tEAF-LF-VD-CC 流程冶炼气瓶钢 30CrMo 时精炼过程中含夹杂物的生成和 转化，对夹杂物进行了三维分析观察。研究结果表明：LF 精炼 30min 后夹杂物中 Mg 含量 减小，Ca 含量增加，镁铝尖晶石夹杂物消失。LF 精炼后期 Mg 含量变化不大，Ca 含量减小， 未出现镁铝尖晶石夹杂物；VD 精炼过程中夹杂物中的 Mg 含量增加，Ca 含量变化不大，重 新生成了镁铝尖晶石夹杂物；精炼过程中镁铝尖晶石夹杂物是可以向复合夹杂物转变的，但 要防止精炼后期镁铝尖晶石夹杂物重新生成必须保证钢液中具有一定的钙含量。 关键词：气瓶钢；二次精炼；非金属夹杂物；镁铝尖晶石 中图分类号：TF769 Study on MgO.Al2O3 based inclusions in alloy steel during Refining LI Gang, LI Jingshee, MA Yu, SUN Liyuan (School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083) Abstract: The formation and transformation of inclusions in gas cylinder steel produced by 90tEAF-LF-VD-CC flow sheet during refining have been studied. In current study, the inclusions were observed by three dimensions. The results show the content of Mg in the inclusions decreased, the content of Ca in the inclusions increased and MgO·Al2O3 inclusion disappeared after 30min when LF refining began; at the end of LF refining, the content of Mg in the inclusions changed a little, the content of Ca in the inclusions decreased and MgO·Al2O3 inclusion didn’t exist; during VD refining, the content of Mg in the inclusions increased, the content of Ca in the inclusions changed a little and MgO·Al2O3 inclusion appeared again; MgO·Al2O3 inclusion can be modified during refining, but in order to avoid forming MgO·Al2O3 inclusions again, the content of Ca in the molten steel have to reach a certain value. Key words: Gas cylinder steel; second refining; non-metallic inclusions; MgO·Al2O3 spinel 30 0 引言 简要回顾研究工作的背景和研究目的，一般 400～600 字，不超过 800 字。在二次精炼 过程中，钢液与耐火材料或炉渣反应，使钢液中的镁含量增加，如果采用铝脱氧则很容易生 成 MgO·Al2O3 夹杂物。MgAl2O4 夹杂物具有稳定的面心立方结构，熔点较高（2135℃）、 35 40 硬度大（HV：2100~2400 kg/mm2）、轧制时不易变形，属 D 类点状不变形夹杂物。MgO·Al2O3 夹杂物尺寸大多数为 2.0–6.0μm，形状有球形、立方体形和不规则形。这类夹杂物会造成钢 铁产品的表面缺陷，降低钢材的抗腐蚀性能，K.Mizuno 和 H. Todoroki 等人在不锈钢表面缺 陷处发现了大量的 MgO?Al2O3 夹杂物[1, 2]。其次这类夹杂物还容易沉积在浸入式水口内部， 造成水口堵塞[3]。 李海波等人[4]研究表明