连铸圆坯表面纵裂原因及控制措施

Causes analysis and control measures of longitudinal cracks on the surface of continuous casting round billet

阐明了圆坯纵裂形成机理,通过解剖分析马钢圆坯纵裂坯壳,采用现场调研和数据分析的方式查清了圆坯产生纵裂的主要原因为:钢水中有害元素硫含量、保护渣性能不良、浸入式水口插入深度不合适及对中不良、铸温铸速不合适、结晶器弧度及冷却强度不合适等。根据现场生产实际情况,通过采取措施,使圆坯纵裂率由0.63%降至0,有效的控制了圆坯纵裂,同时实现了圆坯连铸零纵裂漏钢率。

The formation mechanism of longitudinal crack of round billet was expounded. The main causes of longitudinal crack of round billet were found out by field investigation and data analysis through anatomical analysis of longitudinal crack shell of round billet in Masteel. The main causes were as follows: harmful element sulfur content in molten steel, poor performance of mold fluxes, off-center and improper inserting depth of submerged entry nozzle, unsuitable temperature and casting speed, inappropriate radian and cooling intensity of mould. According to the actual production situation on the spot, some measures were taken to reduce the longitudinal crack rate of round billet from 0.63 % to 0, the longitudinal crack of round billet was controlled, and the zero longitudinal crack breakout rate was realized.