Abstract: The reaction of three kinds of MgO, Al2O3 and MgO+CaO based tundish gunning materials (GM) with molten steel were studied, their effects on the contents of total oxygen, total nitrogen, Al, Ti and Si in steel, and composition, quantity and size distribution of inclusions examined, and the infiltration and erosion of gunning materials at the interface with steel analyzed. The results show that compared with MgO and Al2O3 based GM, the use of MgO+CaO based GM could control the total oxygen content and inclusions in steel better at 1550℃, leading to the improved steel cleanliness with the final oxygen content of 8.5′10-5, and the reoxidation of steel was reduced and the formation of fine inclusions was improved, leading to <1 mm inclusions with 98.13% proportion. Al and Ti were firstly oxidized, and then Si and Mn. The erosion of Al2O3 based GM was mainly caused by wearing, and that of MgO based GM by molten steel infiltration. The use of MgO+CaO GM could reduce the secondary pollution of molten steel, which was more conducive to the production of clean steel.

Key words: tundish, gunning material, inclusion, interface, clean steel, refractory

摘要： 实验研究了镁质、氧化铝质和镁钙质三种中间包内衬涂料与钢水反应，考察了其对钢中T.O, T.N及Al, Ti, Si, Mn含量、夹杂物组成、数量和尺寸分布的影响，并分析了钢水在钢/涂层界面对涂层的渗透和侵蚀程度. 结果表明，在1550℃下，相比于镁质涂料和氧化铝涂料，镁钙质涂料能对钢液T.O和成分有更好的控制，终点氧含量在8.5′10-5，对钢液的二次氧化很少，并有利于细小夹杂物的形成，其中<1 mm夹杂物占98.13%；钢中首先是Al, Ti被氧化，之后是Si, Mn被氧化；氧化铝涂料被损坏的机理主要是冲刷脱落，镁质和镁钙质涂料的损坏则以渗透侵蚀为主. 镁钙质涂料对钢液的二次污染小，有利于洁净钢的生产.

关键词: 中间包, 内衬涂料, 夹杂物, 界面, 洁净钢, 耐火材料