Ceramic foam filter uses
Ceramic foam filter uses
The ceramic foam filter came out at beginning of 70 decade in the last century. Along with 30 years of fast development, the material of manufacturing products are: carbonized
Silica, zirconia, alumina, graphite, etc.; applications include casting steel, cast iron, cast aluminum, and cast copper filtration. Ceramic foam filters can greatly improve surface quality and performance of castings.
Introduction of ceramic foam filters
It is made of polyurethane foam, impregnated with refractory slurry forming process, special high-temperature sintered three-dimensional network structure ceramic products.
Classification by material: alumina, magnesia, silicon carbide, Zirconia, carbon composite; classified by mesh density ppi: 10ppi, 15ppi, 20ppi, 25ppi, 30ppi, 40ppi, 50ppi, 60ppi.
Features of foam ceramic filter
The ceramic foam filter has a unique three-dimensional connected tortuous mesh skeleton structure and 80%~90% open porosity. It has four filtration purification mechanisms, namely: sieving filter cake - deep bed filtration mechanism, flotation separation mechanism, depth filtration (physical adsorption), and rectification mechanisms. It can efficiently filter large inclusions in molten metal and most of the tiny suspended inclusions as small as tens of microns. with refractory fiber compared with dimensional filter screen and straight hole honeycomb ceramic filter, etc., it has higher refractoriness. High, high strength, good filtering effect, high filtering efficiency.
Application of ceramic foam filters
Foam ceramic filters are mainly used in high temperature metal liquid filtration, aluminum alloy, gold Metal Filtration, Ductile Iron/Grey Iron and Non-Ferrous Metal Filtration, Stainless Steel/Carbon Steel and large casting metal liquid filtration, high temperature flue gas treatment, catalyst carrier, automobile exhaust gas purification devices, thermal insulation materials, etc.
Abstract: Discuss the unreasonable design and application of the foam ceramic filter, which leads to the increase of casting defects. The original use of foam
The role of the ceramic filter: ① filter the inclusions in the molten metal; ② rectification, turbulent flow of molten metal; the ultimate purpose, to improve the casting
Quality, improve casting surface defects. However, the unreasonable design in the use process leads to the worsening of casting defects.
Key words: rationalization of foam ceramic filter application
Principles of ceramic foam filters using
The general use principle of foam ceramic filter: foam ceramic filter
The position placed in the gating system: the lower end of the sprue, the runner, the inner runner,
Principles of use:
① The closer the placement position is to the casting cavity, the better, and the lower the
Low probability of secondary oxidation;
② The design of the gating system should be simple.
No other slag blocking measures are considered, which can improve the utilization rate and process of the sand mold
③ The working area of the filter should be 4
times ~6 times to ensure that the pouring speed is not affected;
④ According to the casting alloy
Select the appropriate filter for the type and pouring temperature, and should not be used over temperature;
⑤ Choose the appropriate pore size to really play the filtering effect;
⑥ Do not use a ceramic foam filter to control the pouring speed.
Ceramic foam filters selection
The porosity of the filter is selected according to the type of cast iron being filtered, generally
10ppi for ductile iron; 20ppi for grey cast iron; 30ppi for
Forged; filter area is determined according to the weight of the cast iron being filtered. filter
There are two abilities. To get a satisfactory result, it must be satisfied: ① Metal
Filtration capacity; ② metal flow capacity. Filtering capacity range per unit area
Respectively: gray iron 2.0~3.8 kg/cm2, ductile iron 1.0~2.0 kg/cm2, cast steel
1.0~2.0 kg/cm (2 data as a reference), depending on the casting material and elements
And the purity of the molten metal has changed.
Design of Foam Ceramic Filter Holder
When using green sand, it is best to design a filter seat (self-hardening sand is better),
Prevent man-made impurities from being introduced.
The design of the filter holder should fully consider the ease of filter placement (such as cones).
surface, slope, clearance, etc.) and firm and reliable. Mold support surface at placement
To have rounded corners (wiping edges) to prevent sand washing, you should pay attention to:
①Leaving a 3~5mm overlap on the inflow surface of molten iron;
②The support width of ≥5mm should be reserved on the outflow surface of molten iron;
③ There are 1~1.5mm gaps and sand collecting grooves around the filter to prevent
When inserting, the scattered sand particles are accidentally dropped and brought into the mold;
④The upper surface of the filter should be 0.5~1mm lower than the parting surface to prevent the box from being closed.
When the sand is crushed.