高等级汽车板中间包冶金技术

Tundish metallurgical technology of advanced automotive sheet

高端汽车外板在后续轧制或冲压过程中发生夹杂缺陷的比例较高,为了进一步提高中间包冶金的效果,研究了中间包开孔挡墙对正常浇铸过程中夹杂物去除的影响。为了保证钢液洁净度一致,在中间包内一侧采用了不带孔的挡墙,另一侧采用了开孔型挡墙,浇铸过程中同时取中间包钢水及铸坯试样,并采用Aspex夹杂物自动扫描电镜进行分析。结果表明,正常浇铸时无孔挡坝有利于夹杂物在中间包内的上浮去除,有孔挡坝中间包内钢液流场存在短路流,钢液在中间包内停留时间短,夹杂物来不及上浮,随钢液进入到结晶器和铸坯中。因此,采用无孔挡坝中间包浇铸的钢液洁净度优于开孔挡坝中间包浇铸的钢液。

High-grade automobile sheet has a higher proportion of inclusion defects during the subsequent rolling or stamping process.In order to further improve the metallurgical effect of the tundish,the influence of the perforated dam of the tundish on the removal of inclusions during the normal casting process was studied.In order to ensure the consistency of the cleanliness of molten steel,a dam without holes is used on one side,and a perforated dam is used on the other side of the same tundish.Tundish molten steel samples and slab samples are taken,and analyzed by Aspex inclusion automatic scanning electron microscope.The results show that the dam without holes is beneficial to removal of inclusions in the tundish.There is a short-circuit flow in the molten steel flow field in the tundish of the perforated dam.This leads to a short residence time in the tundish,and inclusions don′t have enough time to float up.It floats up and enters the crystallizer and slab with the molten steel.Therefore,the cleanliness of the molten steel cast by the dam without holes tundish is better than that of the perforated dam tundish.