Thermal Distortion Tester
- Detailed Technology Description
- Presently available Thermal Distortion Testers (TDT) cannot simulate conditions or measure several parameters important for quality assessment of sand composites. In contrast, this new Thermal Distortion Tester (TDT) utilizes composite specimens that can vary in thickness to simulate different mold thicknesses, applies either constant or variable (simulating changing filling loads) pressure on the sample, while accurately measuring four different sample parameters, in real time. Because of its comprehensive capabilities, the TDT will improve sand composite 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. Directional heating of a shaped sand composite during casting generates anisotropic thermal gradients, while pouring molten metal increases the pressure on the mold and core. The heat transfer and increased pressure causes thermo-chemical reactions within the sand composite that result in pyrolysis and increased friability, mold dimensional changes, distortions, veining and erosion. Refractory coatings can be used to improve mold and core surface finish, reduce thermal expansion defects such as veining, and un-bonded sand defects such as erosion, but are costly and cannot compensate completely for instabilities in the sand composite. Consistent molds and cores providing high tolerances requires testing of sand composite samples under conditions that simulate the real-world stresses of the metal casting process.
- Country/Region
- USA
