Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting
In the cold chamber high pressure die casting process (CC-HPDC) for light alloys, the piston lubricants play a key role in protecting the piston tip from wearing and ensure adequate seal with the shot sleeve. However, during the production process, the pouring of overheated aluminum alloy melt into...
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MDPI AG
2025-02-01
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| Series: | Lubricants |
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| author | Jingzhou Lu Ewan Lordan Yijie Zhang Zhongyun Fan Kun Dou |
| author_facet | Jingzhou Lu Ewan Lordan Yijie Zhang Zhongyun Fan Kun Dou |
| author_sort | Jingzhou Lu |
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| description | In the cold chamber high pressure die casting process (CC-HPDC) for light alloys, the piston lubricants play a key role in protecting the piston tip from wearing and ensure adequate seal with the shot sleeve. However, during the production process, the pouring of overheated aluminum alloy melt into the shot sleeve would lead to evaporation and burning of the lubricants once in contact with the piston tip. The burning products, however, would form gas and non-metallic inclusions in the melt which would be transported and injected into the die area and finally trapped in the castings, all of which would affect the mechanical properties of the as-cast samples and deteriorate the product quality. To further investigate this issue, a pilot scale HPDC machine is used and the lubricant burning issue is studied based on material characterization and numerical modelling. The chemical composition, size, and morphology of the burned products are observed using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). In order to better explore the issue of lubricant combustion discovered in the experiment, a finite element model describing the entire HPDC process is established and the burning, motion, and trapping of the lubricant are calculated. The final distribution of the burned products such as gas and non-metallic inclusions are predicted and their influence on final solidification quality of the as-cast products under various process parameters are analyzed qualitatively. Finally, a slow shot velocity range of 0.4–0.6 m/s and an acceleration profile that ramps up to 0.3 m/s over 0–370 mm of the shot sleeve proved to be the most effective in reducing air entrainment and oxide inclusions to alleviate the burning of lubricant on final product quality. |
| format | Article |
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| institution | Kabale University |
| issn | 2075-4442 |
| language | English |
| publishDate | 2025-02-01 |
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| series | Lubricants |
| spelling | doaj-art-9cd76acefa3b4efb9355db1f5b0e8cf92025-08-20T03:43:31ZengMDPI AGLubricants2075-44422025-02-011339910.3390/lubricants13030099Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die CastingJingzhou Lu0Ewan Lordan1Yijie Zhang2Zhongyun Fan3Kun Dou4School of Metallurgy and Environment, Central South University, Changsha 410083, ChinaBrunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, London UB8 3PH, UKBrunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, London UB8 3PH, UKBrunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, London UB8 3PH, UKSchool of Metallurgy and Environment, Central South University, Changsha 410083, ChinaIn the cold chamber high pressure die casting process (CC-HPDC) for light alloys, the piston lubricants play a key role in protecting the piston tip from wearing and ensure adequate seal with the shot sleeve. However, during the production process, the pouring of overheated aluminum alloy melt into the shot sleeve would lead to evaporation and burning of the lubricants once in contact with the piston tip. The burning products, however, would form gas and non-metallic inclusions in the melt which would be transported and injected into the die area and finally trapped in the castings, all of which would affect the mechanical properties of the as-cast samples and deteriorate the product quality. To further investigate this issue, a pilot scale HPDC machine is used and the lubricant burning issue is studied based on material characterization and numerical modelling. The chemical composition, size, and morphology of the burned products are observed using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). In order to better explore the issue of lubricant combustion discovered in the experiment, a finite element model describing the entire HPDC process is established and the burning, motion, and trapping of the lubricant are calculated. The final distribution of the burned products such as gas and non-metallic inclusions are predicted and their influence on final solidification quality of the as-cast products under various process parameters are analyzed qualitatively. Finally, a slow shot velocity range of 0.4–0.6 m/s and an acceleration profile that ramps up to 0.3 m/s over 0–370 mm of the shot sleeve proved to be the most effective in reducing air entrainment and oxide inclusions to alleviate the burning of lubricant on final product quality.https://www.mdpi.com/2075-4442/13/3/99high pressure die castinglubricantsolidificationmathematical modellingdefects formation |
| spellingShingle | Jingzhou Lu Ewan Lordan Yijie Zhang Zhongyun Fan Kun Dou Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting Lubricants high pressure die casting lubricant solidification mathematical modelling defects formation |
| title | Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting |
| title_full | Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting |
| title_fullStr | Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting |
| title_full_unstemmed | Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting |
| title_short | Influence of Piston Lubricant on the Distribution of Defects in Cold Chamber High Pressure Die Casting |
| title_sort | influence of piston lubricant on the distribution of defects in cold chamber high pressure die casting |
| topic | high pressure die casting lubricant solidification mathematical modelling defects formation |
| url | https://www.mdpi.com/2075-4442/13/3/99 |
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