Compared with pour-over treatment process in an open ladle,nodularizing in the Tundish covered ladle has following advantages:(a) reaction fumes and glare could be reduced obviously;(b) magnesium recoverability could be increased greatly(>60%),and the nodularizing alloy expense could be reduced by 30%;(c) temperature drop of molten iron could be reduced by 40 ℃;(d) quantity of oxide slag could b.

Compared with the open ladle treatment technique,nodularizing in the Tundish covered ladle has following advantages:elemination of fume and glare,high magnesium recovery(> 60 %),the nodularizing alloy expense being reduced by 30 %,temperature drop of molten iron being reduced by 40 %,quantity of oxide slag being reduced by 50 %,quality stability and reliability being improved.