小方坯角部纵裂漏钢的成因与控制

由于方坯角部纵裂漏钢事故频繁,通过分析漏钢的特点和机理,认为造成小方坯角部纵裂漏钢的主要原因是结晶器倒锥度小、结晶器液面波动及中间包过热度大、结晶器冷却水质差。通过采用铯137液面自动控制系统,将结晶器倒锥度增大为每米0.8%～0.9%,控制中间包过热度不大于30℃,改善冷却水质,保证浸入式水口对中等措施,降低了角部纵裂漏钢的次数,使铸坯合格率达到99.95%。

Causes Analysis and Control Measures of Longitudinal Corner Crack Bleed-out of Steel Billet

Due to frequent emergencies of bleeding out by the billet longitudinal corner crack, the characteristic and mechanism of bleeding out are analyzed. The results show that the main reasons are small back draught of the crystallizer, large level fluctuation, high degree of superheat of the tundish and the poor quality of the cooling water for the crystallizer. By adopting Cs 137 level automatic control system, aggrandizing the back draught as 0.8% - 0.9% per meter, controlling the degree of superheat less than 30%, ameliorating the quality of the cooling water and ensuring the submerged nozzle centering etc, the times of longitudinal corner crack bleeding out are reduced and the percent of pass of the billet is 99.95%.