双渣线操作提高结晶器浸入式水口使用寿命的工艺实践

基于保护渣对6流140mm×140mm坯连铸结晶器铝锆质浸入式水口侵蚀机理的分析,通过控制结晶器钢液面为折线形周期性波动（振幅为5 mm,周期为2 h）浇铸5 h后升高中间包高度20~40 mm更换水口的渣线位置,扩大了水口被侵蚀的面积,减轻浸入式水口侵蚀深度。生产结果表明,在使用8 h的条件下,水口的侵蚀深度由工艺优化前的15 mm减小到优化后的5.5mm,提高了水口的强度,避免了因更换水口断裂而发生停浇事故。浸入式水口的使用寿命由8 h提高到10~12 h。

Process Practice for Improving Service Life of Submerged Nozzle in Mold by using Double-Slag-Line Operation

Based on the analysis on eroding mechanism of casting mold powder to aluminum-zirconium submerged nozzle during casting 6 strand 140 mm x 140 mm billet, with controlling the liquid level in mold from original plane straight line form to up-and-down periodical fluctuation twist line form ( amplitude 5 mm and cycle for 2 h) and casting for 5 h, then rising tundish by 20 ~ 40 mm to change the position of slag line of nozzle, the eroding depth of submerged nozzle obviously decreases by enlarging the eroded area of nozzle. Production results show that in the condition that the nozzle is used for 8 h, the eroding depth of submerged nozzle decreases from 15 mm before process optimization to 5. 5 mm after process optimization. The strength of submerged nozzle is improved to avoid stopping casting due to exchanging broken nozzle. And the service life of submerged nozzle is improved from 8 h to 10 ~ 12 h.