热轧卷表面缺陷影响因素研究

Study on the influence factors of surface defects on hot rolled coil

通过对成品钢水N含量、是否采用倒角结晶器、连铸拉速以及吹氩量等参数与热轧卷表面卷渣、气泡及翘皮等表面缺陷的数据统计规律的研究,得出如下结论:当成品钢水N质量分数大于4×10^(-5)时,卷渣、翘皮及气泡发生率呈明显增加趋势;采用倒角结晶器后,前述缺陷的发生率为0.95%,低于未采用倒角结晶器时的1.39%;随吹氩量增加,前述缺陷发生率呈先增加后降低规律,当吹氩量在6.1~7.0 L/min范围时,缺陷发生率达最高值1.65%,在吹氩量大于9 L/min时,缺陷发生率迅速降至0.5%以下;随连铸拉速增加,卷渣、翘皮及气泡发生率总体呈增加趋势,拉速在1.0~1.1 m/min范围时,缺陷发生率最低,仅为0.62%,其次是拉速在1.25~1.3 m/min范围时,发生率为1.08%,拉速大于1.35 m/min时,发生率明显增加。

Effect of nitrogen content,chamfered mold,casting speed and argon flow on slag entrapment,gas bubble and shell defect of hot-rolled coil surface has been studied,and it is concluded that when nitrogen content is greater than 40×10^-6,the occurring rate of slag entrapment,gas bubble and shell defect shows a trend of increasing significantly.The defect rate is 0.95% with chamfered mold,while it is less than 1.37% without chamfered mold. As the argon flow increases,the defect rate first increases and then decreases. And when argon flow rate is 6.1-7.0 L/min,the defect rate is1.65%,which is the highest. When argon flow rate is greater than 9 L/min,defect rate decreases to less than 0.5% rapidly. With the increasing of casting speed,slag entrapment,gas bubble and shell defect,the defect rate shows a trend of increasing as a whole. When casting speed is 1.0-1.1 m/min,the defect rate is 0.62%,which is the lowest. When casting speed is 1.25- 1.3 m/min,the defect rate is 1.08%. When casting speed is greater than 1.35 m/min,the defect rate increases rapidly.