The oxide film on the surface of the magnesium alloy semi continuous casting unit is loose and is an active element with strong binding force with oxygen. During melting, it reacts with oxygen, water vapor, and nitrogen in the atmosphere to generate oxides and nitrides, which become impurities. The inclusions are often accompanied by shrinkage and porosity.
Application advantages:
(1) Using a combination of mechanical stirring and gas stirring, the magnesium liquid in the crucible undergoes a circular circulation and up-down tumble flow, allowing the refining flux to fully adsorb the oxide inclusions in the magnesium melt. Due to the specific gravity of the generated compounds being larger than the magnesium melt, they precipitate at the bottom of the crucible during thermal insulation and stand still, with lighter oxide impurities floating on the surface of the magnesium melt, thereby achieving the goal of purifying the magnesium melt. Using this stirring device can greatly improve the combination effect and efficiency of magnesium melt and refining agent compared to ordinary stirrers, and generally can achieve a good refining effect with a small amount of refining agent;
(2) Using a variety of gas mixing protection smelting technologies, this technology has greatly improved the purity of magnesium alloys. Currently, SF6+N2+dry bath air, SF6+CO2+dry bath air, or SO2+N2+dry bath air are commonly used as mixed gases. Our company has successfully applied a gas path control system that supplies gas from the central gas supply system to each production line
(3) According to the specific needs of customers, the corresponding smelting mode has been adopted, and the rod casting system consisting of a resistance heated melting furnace+a resistance heated insulation static furnace+a vertical screw semi continuous casting machine has been successfully applied. The magnesium liquid in the melting furnace is purified by slag removal, and after insulation static, it is transferred to the holding furnace by a liquid transfer pump and a liquid transfer pipe (electrically heated), and then after insulation static, it is transferred to the holding furnace by a pouring pump The pouring tube is transferred to the tundish (front liquid tank) and then transferred from the tundish to semi continuous casting. The mode of regenerative heating gas furnace+holding furnace can also be customized according to needs, thereby improving energy utilization efficiency by 20-30%.