Solidification Kinetics of Graphite Nodules in Cast Iron and Shrinkage Porosity
| Autor: | Simon N. Lekakh, Brenton Hrebec |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science Structural material Precipitation (chemistry) Metallurgy Metals and Alloys Nucleation 02 engineering and technology engineering.material 01 natural sciences Casting Industrial and Manufacturing Engineering 020501 mining & metallurgy 0205 materials engineering Volume (thermodynamics) Mechanics of Materials 0103 physical sciences Materials Chemistry engineering Particle Cast iron Graphite |
| Zdroj: | International Journal of Metalcasting. 10:389-400 |
| ISSN: | 2163-3193 1939-5981 |
| DOI: | 10.1007/s40962-016-0053-3 |
| Popis: | The shrinkage porosity of castings made from cast iron with spherical graphite (SGI) depends on a combination of intrinsic (density and volume of phases, solidification kinetics) and extrinsic conditions related to casting-mold thermo-mechanical interactions. Precipitation of graphite nodules increases the specific SGI volume, and control of the nucleation rate in solidified castings can be used for improving casting soundness. In this article, the method of structural reconstruction of solidification kinetics was used to link the nucleation rate of graphite nodules to experimentally observed shrinkage porosity in a specially designed test casting. An automated SEM/EDX system was used to determine the “true” two-dimensional graphite nodule distributions in the casting sections. These two-dimensional distributions were converted into the volume particle distribution functions (PDF), and the solidification kinetics were reconstructed by applying inverse simulations. The experiments were performed with variations in inoculation and pouring temperature. The shrinkage porosity was compared to the restored sequence of graphite nodule nucleation in the specific casting volumes. It is shown that the second nucleation wave in low-temperature poured and inoculated SGI eliminated interdendritic microporosity. The suggested method could be used in industry to improve the soundness of SGI castings. |
| Databáze: | OpenAIRE |
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