An apparatus for investigating thermal distortion in bonded sands

Abstract

The promises of many new alternatives for sand as a medium for the production of cast metal parts have garnered attention of research and press. Yet, close to 90% of annual cast metal production is still done with sand. Its versatility and ease of use foster rapid innovation in an industry where the ability to change quickly can mean survival. This is especially true for chemically bonded sand. Sand has many pluses, but it is far from perfect. Most of the problems with sand castings are due to variations. These variations are mainly in the characteristics of the medium and the materials being utilized, as well as in the process itself. But even with those variations, the popularity of sand-binder systems keeps increasing, and the search for near-net shaped castings keeps going. In order to accomplish near-net shapes it is necessary to control the thermal distortion suffered by molds and cores, an issue that has not been studied that much in the field. The utilization of the developed device for investigating thermal distortion in chemically bonded sands is presented. The device is capable of placing variable loads on sand-binder samples at metal pouring temperatures. The testing is done without combustible gases. The device, developed at Western Michigan University, has undergone several design modifications that improve ease of use and safety. The basic operation of the device is discussed, and sample distortion curves from performed tests are presented and discussed. The results obtained so far indicate that this apparatus is a useful tool to. generate comparative curves that can be utilized during initial selection of sand-binder materials.