减少宽厚板坯表面纵裂纹的改进实践

Improvement Practice of Reducing Surface Longitudinal Crack of Wide and Thick Slab

分析了钢水碳含量、硫含量、钢水纯净度、拉速变化、浸入式水口参数及结晶器液位波动等对铸坯表面纵裂纹的影响,不合理的化学成分、拉速变化及结晶器液面波动大等是导致纵裂的主要原因。通过相应采取优化钢水成分、优化浸入式水口参数、采用钢包下渣检测技术和结晶器液位控制系统改造等措施,使板坯表面裂纹率由0.76%降到了0.18%以下。

This article analyzed the influences of the carbon content, sulfur content, steel cleanliness, casting speed change, submerged nozzle parameters and mold level fluctuation etc on the surface longitudinal crack of slab. The main reasons caused longitudinal crack were unreasonable chemical composition, large casting speed change and large mold level fluctuation etc. Accordingly, by optimizing steel grade element and SEN parameters, using ladle slag detection technology and the transformation of mold level control system etc, the probability of surface longitudinal crack was reduced form 0.76% to 0.18%.