Reviewing Filter Types for Molten Metal
In the handling of molten metal for casting processes, it’s essential to use filters in the melting unit as well as in the gating and/or riser system. The goal is to ensure the best quality of castings with as little impurities and defects as possible.
There are various types of filters you can apply for this purpose, and understanding each one of them can make it easier to decide correctly when setting up or improving your system.
Factors That Matter the Most When Selecting Filters
With so many types and brands of filters in the market, selecting the right filters for your casting process is paramount, and filtration efficiency is not the only factor worth considering. The filters you pick should also have the following qualities:
- High capacity
- Good strength
- Proper dimensional accuracy
- Increased and consistent flow rate
You may have realized that some of the parameters mentioned above conflict with each other. For example, if a filter has a large capacity, its filtration efficiency may fail to meet the required expectations.
In this case, the best filters are the ones that have been engineered to hit the right balance between all these parameters. A leading manufacturer like Holy Filters creates exemplary molten metal filters for industrial casting by applying ingenious engineering methods coupled with thorough testing. Therefore, you can expect the resulting product to not only be effective but also highly reliable for extended periods of use.
Types of Filters for Metal Casting
Now that you know something about picking the right filters, here are the types you should consider:
1. Fiber Filter Net
This type of filter is made of glass fiber (high-temperature-resistant) and resin. Such filters are best for removing inclusions that are larger than the mesh. Their effect is typically general, and they are quite budget-friendly. Additionally, they have a rather simple production process and are very convenient in most situations.
Keep in mind, however, that they have a fairly low service temperature, generally only being able to withstand temperatures of no more than 1450°C. Additionally, they have low rigidity and impact resistance to molten iron.
2. Stainless Steel Mesh
These filters are usually made of 304, 304L, 316, 316L, etc. They are available in plain and twill weave designs and are common in aluminum casting, metal molding, and low-pressure casting processes.
The main benefits of stainless steel mesh filters are that they are quite simple to produce, less expensive, and don’t pollute aluminum during filtration.
3. HoneyComb Ceramic Straight-Hole Filters
These are normally textured or stamped from ceramic material and have a filtering effect that is better than that of fiber filters. Despite having a high mechanical strength, however, they have a porosity of 30-40%, which is noticeably lower than that of foam ceramics. For that reason, these filters have a lower filtration rate of molten metal when compared to foam ceramics.
4. Foamed Ceramic Filters
These were first introduced into the market in the 1960s and used mainly for filtration of non-ferrous metals. Later, they were applied in processes that involved cast steel, cast copper, and cast iron.
These filters are made by coating foam plastic (used as the skeleton) with ceramic slurry, and then the resulting product is fired at a high temperature. Foamed ceramic filters work effectively with a wide variety of filtering mechanisms but they are quite pricey. They, however, are highly versatile, thus they can be customized to meet your unique filtering needs.
To Sum It All Up,
With the information in this post, you now know more about the different types of filters for molten metal in foundry processes. So if you’re trying to perfect a foundry casting installation setup or improve an existing one, you can pick the right filter type for your needs and get amazing results for a long time.
By teaming up with a top-rated filter manufacturer like Holy Filters, you can get valuable assistance during the selection process to facilitate an even better outcome.
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