In order to ensure the full molten metal filtration, the ceramic foam filter must have a certain pressure head for starting the filtration to overcome the obstacle of surface tension. The pressure head size has a considerable effect on the start of the filter. Generally, it should be greater than 400 mm. The indenter should be correspondingly larger.
The overlapping part of the foam ceramic filter and the mold should be sealed as far as possible to prevent the loss of molten metal from the gap, and the filtering effect is not achieved. For some sand molds, such as wet molds, using the ceramic foam filter alone can easily cause the sand to fall off where the filter is placed. In this way, a filter seat must be designed to support the filter so that the filter does not move under the impact of molten metal. , Prevent sand particles from entering the cavity and metal liquid loss.
Before using the foam ceramic filter molten metal filtration, use compressed air to blow off the surface dust and internal fragments to prevent impurities from contaminating the molten metal. Avoid moisture during transportation and storage, and store in a dry environment. If necessary, bake the ceramic foam filter before use to fully dry the filter. In addition, the filter is a fragile product, so it should be handled with care to prevent damage.
Principles of Ceramic Foam Filter Molten Metal Filtration
①The closer the placement position is to the casting cavity, the better, which reduces the probability of secondary oxidation;
② The design of the gating system should be simple, and other slag-retaining measures can be ignored, which can improve the utilization rate of the sand mold and the production rate of the process;
③ The working area of the filter should be 4 to 6 times the blocking cross section of the gating system to ensure that the pouring speed is not affected;
④Select the corresponding filter according to the type of casting alloy and the pouring temperature, and should not be used over temperature;
⑤Choose the appropriate pore size to really achieve the filtering effect;
⑥ Filters cannot be used to control the pouring speed.