Die-cast aluminum alloy is easy to get gas and oxidized during the smelting process. During the continuous melting process, oxidized slag will be generated on the surface and inside of the molten aluminum. The smelting raw materials are divided into aluminum ingots and recycled materials. The slag content of recycled materials is higher than that of aluminum ingots. After smelting, the slag in the molten aluminum will increase accordingly. The oxide slag is easily absorbed by the gas in the molten aluminum, making it difficult for the gas to separate out from the molten aluminum. AdTech offers ceramic foam filters for oxidized slag removal. It adopts the principle of adsorption to filter, can effectively remove large inclusions in molten aluminum, and effectively adsorb small inclusions.
Due to the presence of gas and oxidized inclusions in the molten aluminum, defects such as shrinkage holes, pores, and slag inclusions are generated in the die-casting parts. High-quality molten aluminum should have the characteristics of a qualified chemical composition, a low content of gas and oxide inclusions, a good casting performance, and a casting mechanical performance that meets the requirements.
There are many kinds of inclusions in molten aluminum. Except for the material falling off of the furnace body, most of them come from the reheating material. In the process of placing and melting the recycled material, oxide inclusions such as alumina and magnesia are formed. Since the recycled material cannot be absolutely clean, and the surface of gates, unqualified die castings and other surfaces will adhere to oily and relatively humid, a large amount of smoke and water vapor will be generated during the melting process, which is the main source of hydrogen. The density test and metallographic analysis of the aluminum ingot before smelting in the same furnace and the return material after casting revealed that the hydrogen content and inclusions in the return material increased significantly.