Journal of Casting & Materials Engineering
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ISSN 2543-9901
Issue Date
2018
Volume
Vol. 2
Number
No. 4
Description
Journal Volume
Journal of Casting & Materials Engineering
Vol. 2 (2018)
Projects
Pages
Articles
New possibilities in thermal analysis of molding materials
(AGH University of Science and Technology Press, 2018) Svidró, Judit; Diószegi, Attila
Molding material-related studies within the research activities concerning foundry technology have always been limited despite the significant effect of molding mixtures on the quality of cast parts. One reason behind this trend is the difficulty in interpreting the results of such complex systems like molds and cores. This paper provides a new possibility for studying the heat-absorption performance of materials used as molding media in metal casting processes. By further developing the Fourier thermal analysis method of cores and molds introduced by earlier studies, the investigation of unbonded sand has become available. The heat-absorption properties of the components can be hereby separated and studied respectively. Thermal analyses were performed on sphere-shaped resin-bonded cores with various binder levels as well as on unbonded sand samples. The temperature data collected from two points of the samples were then used for the calculation of the novel thermophysical properties. The results revealed not only quantitative but qualitative differences in the characteristics of the binder decomposition processes, providing a deeper understanding on the thermal behavior of molding materials. The outcome of the research provides more accurate data, which is the key for the improved simulation of casting processes.
Grain-size prediction model in aluminum castings manufactured by Low-Pressure technology
(AGH University of Science and Technology Press, 2018) Fernández-Calvo, Ana Isabel; Lizarralde, Ibon; Sal, Elisa; Rodríguez, Patxi; Ochoa de Zabalegui Pereda, María Edurne; Cia, Igor; Rios, Ariane
The grain refinement in a real casting manufactured by Low Pressure Die Casting (LPDC) such as wheels and steering knuckles depends on the grain-refinement potential of the metal and the geometry of the part/process parameters. For this study, the effect of the cooling rate on the AlSi7Mg alloy with different metal qualities in terms of grain refinement was tested. The grain size has been metallographically evaluated in cylindrical test pieces and in the real wheels and steering knuckles manufactured at the Mapsa and Fagor Ederlan foundries. The Thermolan®-Al system has been used to evaluate the nucleation potential in terms of grain size on a standard cup. The grain size has been modeled taking into account the effect of the cooling rate measured in the center of the cylindrical test parts and the different grain-size potential. Different grades of refinement have been tested. The grain size measured in a real casting (wheel and steering knuckle) was used to calibrate the model for a real part in LPDC for different grain-size potential.