頁籤選單縮合
題名 | 陶瓷泡沫濾網應用於銘合金重力鑄造=Application of Ceramic Foam Filter in Aluminum Gravity Casting |
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作 者 | 李正隆; 許富淵; | 書刊名 | 鑄造工程學刊 |
卷期 | 39:3=158 2013.09[民102.09] |
頁次 | 頁39-48 |
分類號 | 472.53 |
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; Ceramic foam filter; Runner system design; Gravity casting; Critical gating velocity; Bi-film defect; |
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0.5 m/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,設計了兩種不同方案設計之流道系統,以固定澆鑄高度,並選用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,以便觀察兩種流道設計分別有與無濾網的流體外觀的改變;並且此流體外型的動畫資料,可提供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(reduced pressure test)後,試片最後再使用阿基米德法,量測這些減壓測試後的試片的密度及孔隙率,以比較經過濾網後的鋁合金含氣量與原始鋁液間的變化。 |
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). Moreover, after flowing the foam filter, the static pressure energy of liquid aluminum flow then could be recovered from kinetic energy. Therefore, it could be used for stabilizing the aluminum flow during the filling of mold cavity. And, the formation of so-called bi-film defect, deriving from the surface turbulence and the entrapment of oxide films during filling process, then can be avoided.The purpose of this study is to understand the change of flow profile after flowing through the foam filter in various runner system designs. The runner systems without filters are also tested. Two types of runner systems are designed, and they are all bottom gating system.For observing the flow going through the ceramic foam filter, water analogy method, using dyed water filling test in a transparent PMMA material mold, is applied. This flowing profile could be used for the validation of the result of computational modeling.In the real casting experiment, the aluminum castings in the area of the outlet of the foam filter was sectioned. And these specimens then did re-remelting and reduced pressure test (RPT). The densities of the specimensare measured by Archimedes method. By comparing the density differences between the original degassed liquid aluminum and the casting specimens, the contamination of air (or hydrogen) of the liquid aluminum flowing through the filter is measured. |
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