耐低溫衝擊厚壁球墨鑄鐵件之鑄造技術建立

Abstract

本研究針對2MW大型風力發電機之輪轂鑄件，建立模型設計及製作技術、澆流道及冒口系統設計、模流及凝固分析、呋喃模造模技術、最佳合金設計及熔鑄條件等，以建立2MW大型風力發電機輪轂鑄件之實務鑄造技術，並以化學成份、顯微組織與機械性質之相關性迴歸方程式及模流凝固分析軟體再次驗證研究結果。此外，本研究亦探討Zn-Al合金熔射噴覆處理對於鑄件耐腐蝕性之影響(中性鹽霧試驗及加速酸性鹽霧試驗)。實驗結果顯示，附鑄試樣能符合顯微組織(球化率、球墨數、波來鐵含量)及機械性質(抗拉強度、降伏強度、伸長率、低溫(-20oC)衝擊性能)的規格要求，且200μm厚度以上之Zn-Al合金熔射噴覆層能夠通過120小時之鹽霧試驗。

The primary purpose of this research is aimed at 2MW hub to establish the design of the hub mold and manufacturing, the design of gating system and filling and solidification simulation, furan molding, the optimal alloy design and casting condition for achieving the desired mechanical properties (tensile strength, yield strength, elongation and impact value under -20oC) of 2MW hub used in large-scale windmills. Establish the practical casting expertise of 2MW large-scale windmill hub and use the derived regression equations to inspect and verify the results of chemical compositions, microstructures and mechanical properties. On the other hand, the effect of resistance to corrosion (NSS and CASS salt spray test) of Zn-Al arc spraying coating on the specimens was also investigated in this study. The experimental results show that the cast-on specimens of 2MW hub can meet the specification of EN-GJS-400-18U-LT including microstructure (nodularity, nodule count and pearlite percentage) and mechanical properties. Also, the thickness of Zn-Al arc spraying over 200µm can pass the 120hr salt spray test.