Molten aluminum filtering with ceramic foam filter is the most effective way to remove nonmetallic slag from molten aluminum. In aluminum alloy casting, multilayer glass cloth filters or ceramic foam filters are usually used.
No matter which molten aluminum filtering method is adopted, in order to ensure the normal molten aluminum filtration, the surface scum should be removed before filtering aluminum water, because the surface scum is easy to block the filter screen of the filter. Material that makes filtration impossible. The simplest way to remove scum on the surface of molten aluminum is to set a slag baffle in the runner so that the dross can be removed before filtration.
In order to produce high-quality aluminum alloy casting bar, we should select reasonable composition, strictly control melting temperature and casting temperature, refine grain size, refine alloy liquid, filter liquid aluminum and other process measures, and also must operate carefully to avoid cracking and rolling of oxide film.
Turbulence and rolling of molten aluminum should be avoided as much as possible during casting. Do not use tools to easily stir the molten aluminum in the tank and splitter plate, so that the molten aluminum flows smoothly into the mold under the protection of the surface oxide film. The reason is that the oxide film on the surface of molten aluminum will be broken and new oxidation will be caused by stirring the tools and the flow of molten aluminum. At the same time, the oxide film will be sucked into the molten aluminum.
The results show that the oxide film has strong adsorption capacity and contains 2% water. When the oxide film is contained in the molten aluminum, the water in the oxide film reacts with the molten aluminum, resulting in hydrogen absorption and slag inclusion. Prior to casting, the casting launders, distribution chutes and other casting systems shall be sufficiently preheated and dried to prevent hydrogen absorption due to the reaction of moisture and molten aluminum.
Finally, homogenization of aluminum bars can produce high-quality aluminum rods, which provides a reliable material basis for the production of high-quality profiles.