2MW風力機葉片輪轂系統鑄件之製程及材質控制

Abstract

本研究針對風力機葉片輪轂系統鑄件，建立符合工程規格之合金設計及製程技術。在實驗方法上，探討C、Si、Ni含量及球化接種技術對於顯微組織、抗拉性質、低溫(-20oC)衝擊性質及耐(鹼性)腐蝕性之影響，以建立風力機葉片輪轂系統鑄件之最佳合金設計及製程。本研究擬開發之風力機葉片輪轂系統鑄件須滿足下列工程規格: 抗拉強度大於370 MPa、降伏強度大於220MPa、伸長率大於12%及衝擊值(-20oC) 大於10J(三支平均，每支至少7J)。 根據本研究之實驗結果，可獲致下列之結論: (1)在合金設計方面，最佳之Si含量約為2.1%，而碳當量約為4.0%。(2)欲同時符合抗拉性質及衝擊值之規範要求時，球墨數目應介於120/ mm2 ~ 140 / mm2之間，而波來鐵量應控制在約4%~5%之間。(3) 對於厚件球墨鑄鐵而言，採用二次接種處理方式(例如澆斗接種加上瞬間接種，或澆斗接種加上模內接種)，可使鑄件在金相組織及機械性質方面獲得改善。(4)添加約0.8%Ni對於球墨鑄鐵之顯微組織並無影響，且亦無法提升抗腐蝕性，因此，在實務應用上，鑄件仍應施以防銹處理。

This research focuses on the casting of wind turbine rotor hub system, establishing an engineering-rule of alloy design and casting process. In our experiment, we investigate the influence of C、Si、Ni amounts and the technique of nodularizing and inoculation treatment on microstructure, tensile property, low-temperature(-20oC) impact property, and anti-corrosion property so to arrive at an optimal alloy design and casting process for the manufacturing of the wind turbine rotor hub system. The purpose of this research is to achieve the following engineering-rule for castings of wind turbine rotor hub system: tensile strength of 370 MPa and above,yield strength of 220MPa and above, elongation of 12% and above and impact strength(-20oC) of 10J(an averagy of three specimens,at least 7J of each specimen)。 Based on the results of our research, we conclude that: (1) for the design of alloy, the amount for Si should be approximately 2.1% and the carbon equivalent should be approximately 4.0% (2) as to the tensile property and impact property, the nodule count required is between 120/ mm2 ~ 140 / mm2, and the amounts of pearlite should be in the interval of 4%~5% (3) for thick-walled spheroidal graphite cast iron, suitable post inoculation practice (i.e.ladle inoculation plus instantaneous inoculation, or ladle inoculation plus inmold inoculation) is required to achieve desired microstructures and mechanical properties of the castings, and (4) 0.8% addition of Ni doesn’t have any significant effect on the microstructure of spheroidal graphite cast iron and anti-corrosion property; therefore, in practice, we still have to conduct anti-corrosion practice on castings.