Thermal Erosion Tester
- Detailed Technology Description
- Presently available abrasion test apparatuses for determining the friability of green sand composites do not test composite specimens under real casting conditions. The Thermal Erosion Tester (TET) tests the friability of sand composite specimens, while applying high heat and pressure to the sample, simulating actual conditions encountered by molds and cores during casting. The TET will improve sand system control and accelerate development of formulations for high tolerance molds and cores.
- *Abstract
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Chemically bonded and green sand cores and molds (coated or uncoated) are an important part of metal casting technology and their behavior, when contacting molten metal during casting, is of crucial importance for creating a quality casting with exact tolerances. Friability is a measure of sand's abrasiveness, and it increases, when sand and binder (sand composite) are heated by molten metal, and when pressure increases on the molds and cores during pouring of the molten metal. The heat transfer and increased pressure causes thermo-chemical reactions attributable to the shaped sand composite that result in mold dimensional changes, distortions, and increased friability leading to erosion of the sand. The erosion of more friable sand limits the use of deep pockets in molds because the sand from the top half of the mold is flushed into the bottom half of the mold, causing a defect in the casting. Refractory coatings can be used to improve mold and core surface finish, and reduce sand defects such as erosion, but they are costly and cannot compensate completely for instabilities of the sand composite. The presently used American Foundry Society (AFS) friability test apparatus does not heat the sand composite sample and does not apply pressure to the sample during abrasion testing. The AFS apparatus fails to provide real-world conditions during casting for friability.
- Country/Region
- USA
