1. The main characteristics of the silicon carbide foam filter:
(1) Filter out the inclusions in the casting, reduce the gas in the casting, reduce the degree of turbulence when the metal liquid flow filling, reduce the surface defects in the casting, and significantly reduce the rejection rate of the casting.
(2) Increase the compression tightness of castings, enhance the elongation and tensile strength, and improve the surface finish of castings. Improve the flow of molten metal and increase the filling capacity and feeding capacity of castings.
(3) The design of the pouring system is simplified. The length of cross runner is reduced and the production rate of casting process is increased.
(4) Reduce the processing time and tool damage, improve the surface quality of casting processing.
(5) with extremely high temperature working strength, thermal shock resistance and metal flow impact resistance. In the work of no slag or crack phenomenon, to ensure the filtration quality of molten metal.
(6) It has a highly significant filtering effect. The filtering effect is considerably higher than that of additional filtering elements. Its remarkable filtering effect is related to the filtration mechanism of "velocity criterion".
(7) It can effectively reduce the turbulent flow of liquid metal caused by pouring, make the filling gentle, and avoid the surface defects of casting.
(8) has a large metal flow rate, and the flow rate is stable (different from the straight hole ceramic filter, the flow rate gradually decreases with the increase of the number of trapped inclusions). Even in the case of elevated content of inclusions in molten metal, normal use will not cause blockage of the filter.
(9) It has strong chemical stability, is not affected by the acid and alkaline of liquid metal, and does not alter the chemical composition of liquid metal.
(10) With extremely high dimensional accuracy, can be used in the automatic placement of the filter line.
2. Main basis for selection:
1, according to the use of temperature to select the appropriate type of filter;
2, according to the casting quality requirements and purification effect to choose the appropriate hole density;
3, according to the weight of casting and pouring time to choose the appropriate size.
3. Points for attention:
1. Prevent the filter from moisture during use;
2, before use, the compressed air will be used to wash the filter, to prevent the residue caused by transportation collision into the cavity;
3. the filter should be as close to the cavity as possible to reduce secondary slag.
Four. Additional instructions for other uses:
The filter is mainly used for in-mold filtration. The position of the filter in the gating system is recommended. The best results can be achieved by placing the filter in the cross-runner system as close as possible to the wall of the mold and close to the side of the inner gate to reduce the generation of secondary inclusions after filtration. It is better to set a slag collection bag before the inlet end of the filter sheet to enhance the slag trapping function. The filter can also be placed at the bottom of the straight runner or the bottom of the pouring cup.
The quality of the filter has the conditions:
1. Void ratio and through-hole ratio 80%-90%
2. Normal temperature pressure strength ≥2.0Mpa
3. Operating temperature: ≤1540℃.