济钢300mm厚板坯连铸机的工艺优化

Process optimization of 300 mm thick slab continuous casting machine at Jigang

济钢5号连铸机生产300 mm厚度铸坯时出现许多质量问题。出现的铸坯缺陷有外弧角横裂、表面纵裂纹、中间裂纹。现场实践表明,外弧角横裂产生的主要原因是铸坯在弯曲之前冷却过强。通过喷嘴改造、调整冷却强度消除了外弧角横裂。通过优化浸入式水口尺寸和调整保护渣性能基本消除了表面纵裂纹。通过优化轻压下工艺和消除机械间隙消除了中间裂纹。工艺优化后取得了良好的表面质量和内部质量。

Many quality problems are occurred in the process of the 300 mm thickness slab production at No.5 continuous caster of Jigang. The casting defects include transverse crack at outer arc corner and surface longitudinal crack,middle crack. Field practice shows that the main reason for the transverse crack at outer arc corner is that the slab is too strong to be cooled before bending. By the nozzle modification and the cooling intensity adjustment,the transverse cracks at outer arc corner are eliminated. The surface longitudinal cracks are basically eliminated by optimization of the submerged nozzle size and adjustment of the protective slag property. The middle cracks are eliminated by optimization soft reduction process and elimination mechanical clearance. Good surface quality and internal quality are obtained after process optimization.