关键词: 汽车外板, 大包换包, 大型夹杂物, 夹杂物自动分析, 大样电解, 交接坯

Abstract: In the continuous casting process for producing automobile exposed panel, ladle exchange can have significant impact on the distribution of large size inclusions in the continuous casting slabs. In the present work, the automatic analysis of inclusions and large sample electrolysis methods were used to study the distribution of micro size inclusions and large size inclusions in a 23 m long continuous casting slab produced in ladle exchange process. The results indicate that the ladle exchange has a certain impact on the number density of micrometer sized inclusions larger than 5 μm, but has little effect on the size distribution of micrometer sized inclusions. The ladle exchange has the significant effect on the inclusions larger than 30 μm, with an affected length of 13 m, including 3 m before and 10 m after the second heat starts pouring. The total content and number of large inclusions in the transition slab are much higher than those in the normal slab. The contents index of the inclusions with the sizes of 30－100 μm, >100－200 μm, and greater than 200 μm in the transition slab are 3 times, 1.2 times, and 2.5 times those of the normal slab, respectively. Their numbers index are 4 times, 1.8 times, and 3 times those of normal slab, respectively. The impact of lade exchange on large inclusions in the transition slab can provide reference for determining the length of the transition slab and improving the continuous casting process. 

Key words: automotive exposed panel, ladle exchange, large size inclusions, automatic analysis of inclusions, large sample electrolysis, transition slab