降低连铸板坯表面纵裂纹的生产实践

针对纵裂纹废品比例增加的情况,分析了表面纵裂纹的形成机理,结合济钢第一炼钢厂的实际生产情况,认为产生表面纵裂纹的主要影响因素是保护渣选择不当、设备运行质量不稳、水口插入深度不合理和钢种微合金化特点等,为此,采取了优化保护渣、调整水口插入深度和调整二次冷却条件等一系列的改进措施,铸坯的表面纵裂纹一次合格率由最初的50%提高到92%,轧制退废中的裂纹和结疤退废由改进前的56%减少到了31%。

Production Practice of Decreasing the Surface Longitudinal Crack of Continuously Casting Slab

Because of the proportion increase of longitudinal crack waster,the formation mechanism of surface longitudinal crack is analyzed.Combining the production practice of No.1 steelmaking plant of Jigang,the main influence factors producing surface longitudinal crack are selecting improper mould power,the wrong work of the equipment,the wrong submerging depth of the nozzle and microalloy characteristic.Therefore,a series of improving measures such as optimizing choice of the mould powder and the secondary cooling condition and so on are adopted.Then the proportion of crack free slab increased from 50% to 92% and the proportion of unqualified production due to crack and scar after rolling decreased from 56% to 31%.