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題 名 | 鋁合金熔液經過陶瓷泡沫濾網後雙膜缺陷的形成=The Development of Bifilm Defect as Molten Aluminum Alloy Flowing through the Ceramic Foam Filter |
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作 者 | 李正隆; 許富淵; | 書刊名 | 鑄造工程學刊 |
卷 期 | 40:4=163 2014.12[民103.12] |
頁 次 | 頁9-24 |
分類號 | 472.5 |
關鍵詞 | 陶瓷泡沫濾網; 流道方案設計; 重力鑄造; 臨界鋁合金澆鑄速度; 雙膜缺陷; 雙膜指數圖; Ceramic foam filter; Runner system design; Gravity casting; Critical gating velocity; Bi-film defect; Bifilm index map; |
語 文 | 中文(Chinese) |
中文摘要 | 陶瓷泡沫濾網時常應用於鋁合金重力鑄造的方案設計,其使用目的,除了減低金屬流體速度小於鋁合金之入水口的臨界速度0.5m/s外,最重要經過濾網後,金屬流體因動能回覆成靜壓力能,使得流體能達到整流效果;同時,可以避免在進入模穴時產生紊流而造成捲氣和氧化膜捲入形成所謂雙膜缺陷(bifilm defect)。為了要瞭解鋁合金液體經由不同方式進入陶瓷泡沫濾網後,其流體外型改變的情形,以及對於鋁液品質的影響。本研究運用底澆方式,設計了三種不同方案設計之流道系統,控制三種澆鑄高度,並選用10ppi、20ppi陶瓷濾網及一組未設置濾網進行比較實驗。觀察鋁合金液體通過濾網後的流體外型及流速的變化,是使用透明壓克力模具來做水流實驗模擬試驗,目的要類比模擬鋁合金液體通過濾網的情況,以便觀察三種流道設計與不同濾網條件下流體外觀的改變;並且以此流體外型的動畫資料,進行計算流體力學電腦模擬的驗證。鑄造實驗後,探討金屬液體通過濾網後其鋁液品質變化,是針對濾網出口處附近的鑄件,進行切除取樣,並將這些出口處的試片,經過重熔(re-melting)及減壓測試RPT(reducedpressure test),使用阿基米德法量測這些減壓測試後的試片的密度及孔隙率並進行切面觀察,並透過本研究所新提出的”面積分率”雙膜指數圖("Area normalized" Bifilm index map)進行量化探討。 |
英文摘要 | Ceramic foam filter is normally applied in the design of runner system in aluminum gravity casting. The purpose of using this filter is to reduce the velocity of liquid aluminum under the so-called critical gating velocity (e.g., 0.5 m/s for aluminum alloys). After liquid aluminum flows through the foam filter, its static pressure energy is recovered from kinetic energy. The foam filter then can be used for stabilizing the aluminum flow during the filling of mold cavity. The so-called bi-film defect, deriving from the surface turbulence and the entrapment of oxide films during filling process, can thus be avoided. The purpose of this study was to understand the change of profile and melt quality of liquid aluminum after flowing through the foam filter in various runner system designs. Three types of bottom gating runner systems were designed. For observing the flow going through the ceramic foam filter, water analogy method, dyed water filling test in a transparent PMMA material mold, was applied. This flowing profile had been used for the validating the result of computational modeling. In the casting experiment, the aluminum casting sample in the outlet region of the foam filter was sectioned. These specimens then did re-melt reduced pressure test (re-melt RPT). The bulk density of the specimens was measured by Archimedes method. By comparing the density differences between the original degassed liquid aluminum and the casting specimens, the contamination of hydrogen of the liquid aluminum after flowing through the filter was measured. "Area normalized" Bifilm index map was proposed to quantify the content of bifilm defects within the casting samples. |
本系統中英文摘要資訊取自各篇刊載內容。