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    請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/90213


    題名: 精密鑄造中殼模厚度和保溫棉對縮孔影響的預測—以316L不銹鋼流量計之缺陷改善為例;Effect of shell mold thickness and insulating wool pattern on internal porosity in investment casting of vortex flow meter
    作者: 曾瀚緯;Tseng, Han-Wei
    貢獻者: 機械工程學系
    關鍵詞: 電腦輔助工程;316L不鏽鋼;殼模層數;縮孔;精密鑄造;渦流流量計
    日期: 2022-09-23
    上傳時間: 2022-10-04 12:16:50 (UTC+8)
    出版者: 國立中央大學
    摘要: 在這項研究中,研究了具有不同保溫棉方案和殼模厚度的精密鑄造 (IC) 用於幾何復雜的渦流流量計。殼模面漿由鋯石 (ZrSiO4) 和膠狀二氧化矽 (SiO2) 接著劑組成。鋯砂因其化學穩定性、較高溫度下的抗斷裂性和較低的熱膨脹係數而被認為是一種有潛力的高溫應用工程材料。通過實驗驗證了殼模的基本性能,如機械性質和熱性質。發現斷裂模量為5.6±0.5MPa。傳熱係數 (HTC) 計算為在 600-900 W/(m2 K) 範圍內。後來作為軟體模擬的資料庫輸入。此外,使用電腦輔助工程 (CAE) 方法和測試,該研究調查了不同層數和保溫棉方案的熱性質是否會影響鑄造缺陷的形成。CAE 模擬顯示初始層數方案會導致管壁問題。為了減少熱點區域,第一步是採用不同的保溫棉方案,這可以將縮孔形成的概率降低 17%,第二步是增加模殼的厚度以減少熱點形成的百分比。經計算後,最優化設計可使縮孔形成的概率降低 47%。通過改變殼模的厚度,不同的熱性質可以顯著減少批量生產的渦流流量計的鑄造缺陷。在這項研究中,渦流流量計改進的最佳解決方案已被鑄造廠採用並量產,而後X光檢測在渦流流量計管壁常有缺陷的地方,結果判定為無缺陷,驗證了保溫改進方案的效果和可行性。;Investment casting (IC) with different insulating wool pattern and shell mold thickness is investigated for a geometrically complex vortex flow meter in this study. The primary coating consists of zircon (ZrSiO4) with colloidal silica (SiO2) binder. Zircon is regarded as a potential engineering material for high-temperature applications for its chemical stability, strong fracture resistance at higher temperatures, and low thermal expansion coefficient. The fundamental properties of the shell mold, such as mechanical property and thermal properties were experimentally validated. The modulus of rupture was found to be 5.6±0.5MPa. The Heat transfer coefficients (HTC) was calculated to be in the range of 600-900 W/(m2 K). Later as the input data for numerical simulation. In addition, using a computer-aided numerical (CAE) approach and tests, this research investigated whether the thermal properties of varied layer thicknesses and insulating wool patterns may impact the formation of casting defects. The CAE simulation reveals that the initial layer thickness would result in pipe wall problems. To lessen the hot spot region, the first step is to employ different insulating wool patterns, which could reduce the probability of shrinkage forming by 17%. The second step is to increase the thickness of the mold shell to reduce the percentage of hot spots. It is calculated that the optimal design would reduce the probability of shrinkage forming by 47%. The varying thermal properties may significantly decrease the casting faults of a mass-produced vortex flow meter by altering the thickness of the shell mold. In this study, the best solution for vortex flow meter process improvement has been adopted by an IC foundry and mass-produced. The X ray inspection shows flawless results in the vortex flow meter pipe wall where defects often form, and proves the effect and feasibility of the thermal insulation improvement proposal.
    顯示於類別:[機械工程研究所] 博碩士論文

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