What is the impact of casting filter quality on filter performance?

In recent years, the quality requirements for castings have become increasingly higher, including dimensional accuracy, surface finish, and usage functions, etc. The introduction and application of metal liquid filtration technology has played a great role. Casting filtration technology has changed from no filtration to the use of fiber casting filters, and the quality of castings has been greatly improved. However, there are now a variety of filters, and the quality is even more uneven. Quality is the guarantee of filter performance and filtration efficiency, and it is also an influencing factor.

1. The impact of casting filter quality on filter performance

The impact of casting filter quality on filter performance is mainly reflected in four aspects: one is the impact on thermal shock resistance; the second is the impact on chilling resistance; the third is the impact on pore uniformity; and the fourth is the impact on dimensional accuracy. It can be seen that inferior filters not only do not help casting, but also cause problems such as insufficient pouring, cold shut, and increased inclusions. Therefore, when we buy, we must choose high-quality filters.

1. The influence of quality on thermal shock resistance

The quality of the filter has a certain influence on its thermal shock resistance, because when the filter is generally manufactured, a specific proportion of high-temperature resistant chemical raw materials are evenly coated on the glass fiber cloth carrier, and then made. And when casting, the position of the filter is generally as close to the living room as possible, and there is a certain height difference between the distance from the pouring cup, so the molten metal will produce a certain thermal shock to the filter under the action of the pressure head. This requires that the quality of the filter must be good and can withstand this thermal shock. The inferior filter will not be able to resist, causing cracking or even melting. In this way, it will not only fail to effectively filter the molten metal, but also slag.

2. The influence of quality on anti-chilling performance

The casting filter is made of glass fiber yarn. The glass fiber yarn material belongs to non-metallic refractory materials. The pouring temperature of the casting molten iron is about 1400℃, and the molten steel is higher. When the hot molten metal rushes into the filter with a temperature difference of more than 1000 degrees, it is a test of the anti-chilling performance of the filter. Poor-quality filters crack and break due to poor slurry preparation and sintering process, and the consequences are the same as those of poor thermal shock resistance mentioned above.

3. The impact of quality on porosity uniformity

The filter relies on its internal absorption and filtration of some inclusions smaller than the void size. Casting workers are worried that poor-quality filters will be blocked too early, which will cause defects such as lack of meat and cold shut caused by insufficient pouring, and serious ones will be scrapped. To improve the porosity and porosity uniformity of the filter, it is necessary to rely on the specific ratio of slurry, strict sintering process and high-quality glass fiber yarn. Different porosities can be made according to the different types of casting alloys and process requirements. For example, ductile iron mostly uses a 10PPI filter with larger holes, which has about 10 holes per inch; gray iron mostly uses a 30PPI specification; it can also be made into a 20PPI between the two. Porosity cannot be actively controlled by poor-quality filters at all, and products are often roughly classified after firing. This type of filter appears to have holes on the surface, but its internal grid is blocked and the proportion of blind holes is large. If it is not broken or melted by the molten metal during pouring, it will quickly become blocked. This indicator of the filter is mainly determined by visual inspection and pouring tests.

4. The influence of quality on dimensional accuracy

The dimensional accuracy of the casting filter includes the three-dimensional dimensional accuracy and flatness of the shape. Whether the filter is used for wet sand or self-hardening sand, a small dimensional tolerance is required, so that it can be well matched with the holes prefabricated on the sand mold for placing the filter. High-quality filter king can achieve neither the phenomenon of "large sheet and small hole" that cannot be placed, nor the gap between the filter and the hole is too large to cause the metal liquid to bypass.

The flatness of the filter is equally important. If it is warped, in addition to the easy occurrence of metal liquid bypass during pouring, it will also cause uneven force, especially for self-hardening sand molds, increasing the risk of the filter being damaged due to thermal shock. The dimensional accuracy can be measured using a caliper. Flatness is determined by placing the filter on a flat surface (such as flat glass) to observe its degree of warping.

2. Uses of filter screens

Food industry: used to make juice, various beverages, eight-treasure porridge, cooking oil, etc.

Chemical industry: filtration, separation and purification of various chemical substances.

Petroleum industry: refineries, gas stations.

In addition, filter screens can also be used for auto parts. I believe that filter screens will develop more uses in the future.

3. Types of filter screens

According to different raw materials, they can be divided into: stainless steel, hot-dip galvanized, copper, aluminum

According to different styles, there are various styles: cylindrical, cylindrical, disc, bowl, ring, disc, square, cap-type filter screens, etc.

According to different processes, they can be divided into: stamping process, spot welding process, roll welding process, argon arc welding process, tin welding, silver welding, etc.

According to the purpose, they can be divided into: water treatment, dust filtration, oil-water separation, oil mist separation, chemical particle separation, solid-liquid separation, etc.

4. What are the characteristics of casting filter nets?

The raw material of casting filter nets is high silica glass fiber filter nets, which can be used for filtering cast aluminum, cast copper, gray castings, ductile iron and small cast steel parts. It is made of high silica glass fiber mesh cloth and frosted mesh cloth, and the surface is coated with high temperature resistant coating to make a mesh with a certain degree of rigidity. The filter net is cheap, easy to use, does not change the metal composition of the casting, has good slag filtering effect, and has low gas emission.

In addition, it also has high temperature resistance, corrosion resistance, good chemical stability, resistance to metal melt erosion, good strength and low gas emission. It can also filter out impurities, reduce casting inclusions and pore defects by more than 50%, and greatly reduce the defective rate. It can also avoid turbulence and eddy currents of molten metal during pouring, achieve stable filling, reduce secondary oxidation, and greatly improve the internal and surface quality of castings. Therefore, the casting filter net is an ideal filter material for various types of metal melts, and it can also be used for filtering chemical corrosive liquids and high-temperature gases. The types of filters include aluminum water filter nets, iron water filter nets, cast steel filter nets, etc.

The working temperature does not exceed 1600 degrees, the softening point is 1400 degrees, and the gas emission is less than or equal to 60CM3/g for 5 minutes of continuous working time. Casting filter nets can be divided into three types according to the mesh specifications: 1.5mm, 2.0mm, and 2.5mm. According to the shape, they are divided into sheet filter nets, cylindrical filter nets, cap filter nets, etc.

The casting filter net is made of 304 stainless steel wire mesh or perforated plate net as raw materials through multiple processes. Its characteristics are as follows:

High tension: The tension is much higher than that of ordinary polyester nets.

Ultra-precision: Uniform wire diameter and aperture, extremely low difference.

Low elongation: The elongation of the wire mesh is very small.

High flexibility: easy to disassemble.

High corrosion resistance: It has excellent corrosion resistance, exceeding polyester fiber.