IMPREGNATION OF VACUUM CASTING
During the casting process, gases released into the molten metal, and these causes gap of continuity, inclusions, pores, shrinkage cavities in the solidified material. For castings where the liquid or gas-density must be 100%, leads to refuse materials.These parts can be mostly saved efficiently, when the pores are filled in with polymerises plastic by vacuum.
The appearance of pores have three typical types:
TYPES OF INCLUSIONS AND PORES
In good case, there is not a problem. But it may easily occur, when need more proccessing during the treatment of material removing, the inclusions open up and becomes a blind pore or through pore.
The blind pore
Generally, this is a non-permeable, but depending on the thickness of the wall the internal corrosion can easily break through the thinnest point. It’s also disadvantageous because of the retention of contamination.
It causes most of the problems. Often invisible, the leak can appreciable only under pressure.
WHY VACUUM SEALING?
Frequently the size of the pores are microns but in the millimeter wide channels or blind pores the sealant is not absorbed into, because of the air opposition and viscosity of the sealant inside. In the vacuum sealing, we take the pieces around with vacuum, and then we filling into the sealing liquids. As a result of pressure, the pores absorb and keep in the sealant.
WHY POLYMERIZATED MATERIAL?
The pores can keep the material, but under pressure there is no significant opposition. The ULTRASEAL company has developed a group of materials, which can change under heat-treatment, and become as a flexible solid material and resist of pressure, vibration and chemical effects. All significant quality control company and users tested and approved these materials.
Microscopic picture of a cross section of castings.
Hungaromarket, as the Hungarian representative of the company of ULTRASEAL, has the appropriate equipment materials and licenses to conduct this process. Our specialty, next to the typical small parts, is the vacuum impregnation of large pieces as well. (e.g.: pump- house)
The simplified process of impregnation.