30t～50t下注大钢锭质量分析及改进

Quality Analysis and Improvement of 30 t～50 t Bottom Poured Heavy Ingot

对30 t^50 t下注大钢锭检测不合格的原因进行了深入的研究与分析,发现主要缺陷为夹渣及白点。采取优化钢锭模设计参数,即增加冒口容积,提高钢锭锥度,降低钢锭高径比,另外还适当增加钢水浇注过热度、降低浇注速度等,充分去除钢锭模内上浮的钢水夹杂物。同时通过加强保护浇注,冶炼过程的钢水去气、去夹杂,脱模后钢锭的缓冷等操作,最终使得30 t^50 t下注大钢锭检测不合格问题得到了有效控制。

The unqualified reason of 30 t- 50 t bottom poured heavy ingot has been thoroughly studied and ana- lyzed. It showed that the major defects are slag inclusion and flakes. By adopting the optimized design parameters for ingot mold, such as increasing the volume of riser, increasing tile taper of ingot, redu~：ing the height-diameter ratio of ingot, appropriately increasing the superheat degree of molten steel and reducing the pouring rate etc. , the floating inclusions of molten steel in the ingot mold couht be removed adequately. Meanwhile, by strengthening the protection for pouring process, degassing and removing the inclusion for molten steel during smelting process, slow cooling after remolding, the unqualified issue of 30 t -- 50 t bottom poured heavy ingot has been effectively controlled eventually.