Covering flux is the continuous addition of powder or granular slag to the molten steel of the crystallizer. Aluminum additive manufacturer SATA will introduce the effect of covering flux below:
(1) Insulation with covering flux to avoid heat dissipation;
(2) Covering flux can isolate the air. The covering flux prevents the oxygen in the air from entering the molten steel and causing secondary oxidation, which affects the quality of the steel.
(3) The covering flux absorbs and dissolves the inclusions floating from the molten steel to the steel slag interface to purify the liquid steel;
(4) The covering flux has a layer of slag film between the mold wall and the condensation shell to smooth the effect, reduce the casting resistance, avoid the condensation shell and copper plate bond;
(5) The covering flux fills the air gap between the billet and the mold to improve the heat transfer.
During the casting process, the liquid covering slag layer squeezes into the shell and copper wall through the interface of molten steel and copper walls due to the oscillation of crystallizer and downward movement of condensation shell. The covering agent forms a solid layer of slag film outside the copper wall and a layer of liquid slag on the solidification shell, which makes the shell formed on the crystallizer call and covering flux smooth, making covering flux like oil motor shaft rolling with the lubricating oil.