Journal of Korea Foundry Society (한국주조공학회지)

Korea Foundry Society (한국주조공학회)
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A Study on the Characteristic of Gas Pore Formation in Lost Foam Casting of Mg alloy;Comparison with Al alloy

마그네슘 합금의 소실모형주조 시 기포형성 특성에 관한 연구;알루미늄 합금과 비교

  • Published : 2004.06.20
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Abstract

The pore formation characteristic of Mg alloy during Lost Foam Casting(LFC) was investigated with reduced pressure test and real casting, which was compared with the results of previous work for Al alloy. Cast Mg alloys in LFC had much lower porosities in comparison with those of Al alloys. Also, the proper pouring temperature gave the minimum porosity like Al alloy although it was higher than that of Al alloys due to the worse fluidity of Mg alloy. The pore formation mechanism of Mg alloy in LFC was similar to that of AI alloy but the critical temperature showing the different mechanism is higher than that of Al alloy as much as $30{\sim}50^{\circ}C$. The result that Mg alloy in LFC had the lower porosity comparing with Al alloy was due to the extra solubility of hydrogen gas although the solubility of Al alloy was easily exceeded by the external sources like pyrolyzed polystyrene products. The mold evacuation gave the lower porosity due to the removal of polystyrene pyrolysis products, and reduced shrinkage defects. Also, there was a proper evacuation pressure that gave a porosity of almost 0vol%. But much higher vacuum degree than this proper pressure caused the severe entrapment of polymer pyrolysis products that gave the large porosity.

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References

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