In order to reduce the influence of gas and non-metallic inclusions, on the one hand, people put forward strict requirements on the raw materials and smelting process of alloy preparation. On the other hand, they are committed to the research and application of advanced new technologies for melt purification. Since 2012, AdTech has been committed to researching on-line degassing devices and filtering devices for molten metal purification technology. Now, AdTech molten aluminum purification equipment has been widely used in aluminum foundries. Foam ceramic filters for casting are the most economical method in molten aluminum filtration technology.
Aluminum alloy is easily inhaled and oxidized during the casting process. Therefore, gases and various non-metallic inclusions are present in the melt to varying degrees, leading to defects such as porosity, porosity and inclusions in the ingot. Significantly reduce the mechanical properties, processing properties, fatigue resistance, corrosion resistance, and anodic oxidation properties of aluminum, and even lead to product scrap.
In addition, due to the influence of raw materials and auxiliary materials, there may be other metals in the solution that are harmful to the solution. For example, alkali metals and alkaline earth metals (such as Na and Ca), certain alkali metals have an adverse effect on the performance of most aluminum alloys. For example, in addition to causing “sodium brittleness” in Al-Mg alloys containing sodium, sodium also reduces the fluidity of the solution. It affects the casting properties of the alloy.
Therefore, special process measures need to be taken during the casting process to remove the gas, non-metallic inclusions, and other harmful metals in the aluminum alloy to ensure the quality of the aluminum alloy.
Foam ceramic filters are used for molten aluminum casting filtration for long-term temperature loads. Molten aluminum filters are usually used in standard sizes (shown in inches) with a porosity of 10 to 60 PPI (pores per linear inch). The size of the ceramic foam filter depends on its porosity and is selected according to the filtering capacity, casting time, and the layout of the CFF filter box. The choice of the porosity of the molten aluminum filter depends on the specific alloy, the temperature of the casting, the metal contamination, and the required output quality.
Before casting itself, the filter must be fully preheated to ensure its normal operation. After the event, if the CFF filter box is equipped with a permanent heating function, the filter can be reused. If metal is filled in the ceramic foam filter, it must be replaced in the next casting event.