With the rapid development of the foundry industry, the requirements for the cleanliness of molten metal and the performance of castings are getting higher and higher. In recent years, the ceramic foam filter has been widely used in casting production, and it has become the simplest and most effective method to improve the mechanical properties of castings and reduce pores and inclusions.
At present, there are more and more manufacturers producing alumina ceramic foam filter in China, the production and use of alumina ceramic foam filters have also increased significantly, but the product quality is uneven, which brings trouble to casting manufacturers in choosing alumina ceramic foam filters. If the selection is not appropriate, not only the expected results cannot be achieved, but it will bring more trouble to the casting production and even increase the rejection rate of castings. Therefore, the reasonable selection and correct use of alumina foam ceramic filters in casting production is a problem faced by foundries.
When selecting alumina foam ceramic filter, its filtering capacity should be considered:
1. The filtration flow of each filter is limited. Usually, a filter can be placed on the bottom of the sprue for castings less than 100kg. But for large castings, you must consider placing two or more filters, usually in the runner or in the runner.
2. Filters with the same mesh pore size can filter different metal liquids, and their filtration capacity is different. Taking a filter with a pore size of 10ppi as an example, the filtration capacity per unit area is 2.0~4.0 kg/cm2 for gray cast iron, nodular 1.0~2.0 kg/cm2 for cast iron, 1.5~3.0kg/cm2 for ordinary carbon steel and low-alloy steel, 2.0~4.0kg/cm2 for stainless steel and high manganese steel. When the mesh size drops by 10ppi, the filtering capacity drops by 20%~30%.
3. As long as the effective use area of the filter is calculated, and then multiplied by the filtering capacity per unit area, the total amount of molten metal filtered by each filter can be obtained.