Effect of Roundness and Surface Roughness of Foundry Sand on the Temperature Change of Sand Cores for Aluminum Casting
Organic binder in sand cores, such as phenol-formaldehyde binder, rapidly decomposes above 550 K, releasing gases including volatile organic compounds (VOCs) and hydrocarbon gases. A rapid temperature rise in the core increases gas evolution during the casting process. The roundness and surface roug...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/15/1/88 |
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| Summary: | Organic binder in sand cores, such as phenol-formaldehyde binder, rapidly decomposes above 550 K, releasing gases including volatile organic compounds (VOCs) and hydrocarbon gases. A rapid temperature rise in the core increases gas evolution during the casting process. The roundness and surface roughness of foundry sand particles influence temperature changes in sand cores. This study investigates how these factors affect temperature change in packed sand beds and cores and the gas porosity at the interface between the core and the A356 Al castings. Temperature changes were measured using three types of sand: angular artificial sand (AAS), natural sand (NS) with different roundness and surface roughness, and polished AAS with a smooth surface. Additionally, the temperature rise in cores was measured with varying proportions of AAS. Packed sand beds and cores with low roundness and rough surface morphology form macro and micro-gaps due to high porosity and surface roughness. These gaps, filled with interstitial gas of low thermal conductivity, hinder heat conduction. Delaying the temperature rise of the core could reduce weight loss from binder decomposition, thereby decreasing gas porosity at the interface between the A356 Al castings and the core. These findings on the effects of roundness and surface roughness on temperature changes in packed sand beds and cores provide methods for reducing gas emission during the casting process. |
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| ISSN: | 2075-4701 |