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.