15 10月 Zirconia Cff
When use Zirconia Cff, inclusions are captured on a filter installed in the metal flow path. They capture oxide films, but not small inclusions. A more efficient filtration is ensured by using ceramic foam filters (PCF), which are a spongy ceramic structure in which molten metal moves along a winding path.
It is advisable to place Zirconia Cff in such places of casting equipment where a large throughput is required, for example, in the channels of pouring glasses.
The main advantages of PCF: minimal resistance to the processed metal melt; high temperature resistance and mechanical strength; a qualitatively new level of processing of liquid metals and alloys.
The use of ceramic foam filter allows to obtain metallurgically pure metal of high quality.
Effective capture of inclusions scattered in the molten metal improves the quality of the casting not only in terms of internal cleanliness, but also surface quality and mechanical strength.
In addition, the use of a filter promotes degassing of the melt. However, a significant drawback of this method is the still high cost of PCF, as well as the need for some melt overheating to facilitate the start-up and operation of the filter.
In addition, Zirconia Cff require the use of a special device to fix them during operation.
Work is also underway to address these shortcomings.
Thus, at the Department of Foundry and Metallurgical Processes and Alloys of the State Technical University, N. Novgorod, an original technology has been developed for manufacturing PCFs from cheap, non-deficient materials – waste from metallurgical and chemical industries.
Evaluation of the efficiency of cleaning aluminum melts in molds using PCFs made using the new technology was carried out under production and laboratory conditions on AK5M2 alloy.
We studied technological modes and filtration parameters: pouring duration, hydrodynamics of the melt flow in the gating system, thermal filtration mode, chemical interaction of filters with the melt, mechanical strength of PCF under high temperatures, the size of porous filter cells, and more.
In this case, the PCF can be installed anywhere in the gate system, in casting ladles as an internal partition and so on.
In the first stages of the study, PCFs were installed in a gate cup at the entrance to the riser.
PCF was used with a thickness of 15 mm, porosity of 85%, with an average cell size of 2.5 to 3 mm.
The aluminum melt was poured at a temperature of 730 ° C into a chill mold heated to a temperature of 250 ° C.
The casting has a massive central cylindrical part with upper and lower flanges and a mass of 6 kg.