The oxide film on the surface of molten magnesium is loose, as it's an active element with high oxygen binding force, so it can react with oxygen, steam,
and nitrogen in the atmosphere, generates oxide and nitride which becomes impurities. The impurities often is accompanied by shrinkage and porosity.
The melting process of magnesium and magnesium alloy is as follows:
(1) Mechanical stirring and gas stirring combined so as to remove magnesium oxide impurities, the molten magnesium will steadily flow in circle during
refining process, this can help the oxide inclusions in molten magnesium can be fully adsorbed by refining agent, and then precipitate in the bottom of
the crucible. Compared with the traditional melting furnace, it can save refining agent by more than 40%;
(2) Use the new protective gas technology in melting which greatly improve the purity of the magnesium alloy, the commonly used gas combination is
SF6 + N2, SF6 + CO2 or SO2 + N2, we succeeded in trial of new protective gas combined by CO2 + argon + xenon;
(3) We successfully using melting mode of 3+1 or 4+1 which can save energy consumption, According to the customer's specific needs, we equip
three/four gas or resistance heating furnace on a heating, holding electric resistance furnace.
(4) Gas melting furnace is controlled by PLC double regenerative waste heat utilization system, it can save energy by 25-30%;
(5) Melting furnace, holding furnace work independently. The molten magnesium is transferred to the holding furnace by the U-shaped infusion tube which can automatic heat the magnesium ,then the molten magnesium pass through the metering system ,flow to the terminal magnesium equipment such as magnesium alloy ingot casting machine, semi-continous casting machine,slab continous casting and rolling mill, it realize safe and efficient automated melting production.
