The control measures of using temperature of fiberglass cap filter

Cap type fiberglass filter mesh is usually a network structure, which is a non-metallic liquid metal purification device with the required mesh opening. Its porosity is higher, the slag collection surface area is larger, and it can reduce the the Reynolds number of the mesh metal surface flowing through the cast filter, then it can make the filler be more stable and reduce the production of secondary oxidation slag in the mold.

The usage of cap type fiberglass filter mesh can effectively remove liquid metal and non-metallic inclusions, improve the structure and mechanical properties of castings, improve the high quality standards of precision castings production and reduce the rate of casting defects. It can also reduce tool wear during machining and significantly improve efficiency. In addition, it can reduce porosity in the casting, reduce surface defects and reduce casting and filling lines, significantly increasing the process yield, which is much better than high silicon screen casting filters and cast filter products with straight holes.

For some castings that require high surface quality and good densification, in order to prevent inclusions and improve the internal quality of the castings, it is very necessary to install a cap type fiberglass filter mesh in the gate system. Especially in the field of small and medium-sized castings such as automobiles, high-speed railways, machine tools and hydraulic parts, the purification effect of the cap filter mesh has been widely recognized by most foundry workers.

The cap fiberglass filter mesh cost is cheap, easy to use, it can improve the mechanical properties of castings without changing the metal composition, improve the production quality of castings. At the same time, it is resistant to high temperature and ablative properties, and it can operate at temperatures of about 850 degrees.

Temperature of using this cap filter is quite important, it will decide the filtration results.

What is the control measures of using temperature of fiberglass cap filter?

1. Do not exceed the filter operating temperature.

From the perspective of filtration, exceeds the working temperature limit, the filter will lose its original performance because of overheating softening, and it will not play the role of filtration. Therefore, the working temperature of the filter must not be exceeded.

2. Use induction furnace for smelting.

In production, using induction furnace melting can better control the liquid metal temperature. Reasonable control of the pouring process, to consider the time required for each step, to avoid some step that waited for a long time to make liquid cool. This requires that the liquid metal initially have a certain overheating temperature, and pay attention to heat preservation at any time during the pouring process.

3. Increase the temperature of liquid aluminum when coming out from smelting furnace.

It is necessary to increase the temperature of the aluminum liquid and appropriate sedation to facilitate the floating and aggregation of non-metallic inclusions. Remove the residue on the surface of the liquid aluminum, and put the covering agent (perlite, plant ash, etc.) on the surface of the liquid aluminum to prevent the oxygenation of the liquid aluminum. Choose the appropriate pouring temperature, try not to lower than 1350℃.

4. Shorten the solidification time.

Under normal circumstances, the higher the pouring temperature, the greater the tendency of graphite to float, because the casting in liquid state for a long time is conducive to the precipitation of graphite. It is found that if the solidification time is shortened, the floating tendency of graphite decreases with the increase of pouring temperature.

In summary, in the case of grasping a reasonable pouring time, the appropriate working temperature of the filter is very reasonable for the casting, after all, the design of fiberglass cap filter is to reduce the scrap rate of the casting.