Ceramic foam filter is the most effective method to remove inclusions in aluminum melt, and it is the first choice for aluminum melting and casting workshops. The ceramic foam filter plate can not only remove the larger inclusions in the aluminum alloy melt, but also filter out the fine inclusions, significantly improving the mechanical properties and appearance quality of the castings.
The ceramic foam filter plate has a multi-layer network and multi-dimensional through holes, and the holes are connected to each other. When filtering, the molten aluminum carries inclusions and flows along the tortuous channels and pores, and is directly intercepted, adsorbed, deposited, etc. when it comes in contact with the foam framework of the filter plate. When the melt flows in the hole, the channel of the filter plate bends, the melt flowing through the channel changes the flow direction, and the inclusions collide with the hole wall anvil and firmly adhere to the hole wall.
The filtration efficiency of the foam ceramic filter board is closely related to its correct installation and use. Its installation and use generally need to pay attention to the following aspects:
1. Choose the correct filter plate:
The selection of ceramic foam filter size and number of holes must take into account the flow range of the specific casting, the highest level of metal during filtration, the total filtration volume, and the cleanliness of the raw aluminum liquid.
2. The pre-treatment of melt filtration cannot be ignored:
Such as normal slagging and cleaning of aluminum melting furnace and holding furnace; refining in the furnace, etc. Especially the online degassing device is still very necessary, because it can not only reduce the hydrogen content of the melt, but also remove some non-metallic inclusions.
3. The filter plate must be matched with square refractory base bricks:
The two are conveniently sealed, which can prevent the metal from flowing into the casting box from the gap without being filtered, and can prevent the foundry ceramic filter from being too light and floating in the aluminum water and failing.
4. Warm-up before use:
Preheat to remove moisture and promote initial instant filtration. Electric heating or gas heating can be used for preheating. Under normal circumstances, it takes about 15 minutes.
5. In the normal filtering process, there is no need to discharge slag, avoid knocking and vibrating the filter plate. At the same time, the launder should be filled with liquid aluminum to avoid worrying too much about liquid aluminum.
6. After casting, drain the metal on the runner and filter plate. There is a kind of vibrator abroad, which is placed on the filter plate and vibrated for one minute to shake off about 75% of the remaining liquid metal on the filter plate.
7. Finally, clean the surrounding area and take out the filter plate after solidification.