本研究採用沃斯回火球墨鑄鐵製作成雙環型試片，控制沃斯回火熱處理變數，以探討雙環型球墨鑄鐵試片經不同沃斯回火熱處理後對微觀組織與機械強度的影響。
實驗結果顯示，隨回火溫度變化，沃斯回火球墨鑄鐵的基地組織也隨之改變。250°C回火的基地組織以下變韌體與麻田散體為主；300°C回火後的基地主要組織則為下變韌體；350°C回火後，組織以下變韌體為主，還有殘留沃斯田體與部分上變韌體；在400°C回火的球墨鑄鐵雙環型試片，則以上變韌體為主，以及殘留沃斯田體與部分下變韌體。
沃斯回火球墨鑄鐵在製作成雙環型試片後，其性質表現受沃斯回火溫度有極大的影響，沃斯回火時間的影響則小於沃斯回火溫度。在本研究沃斯回火溫度變數（250°C、300°C、350°C及400°C）中，沃斯回火球墨鑄鐵雙環型試片強度表現最佳的沃斯回火溫度為350°C，而在350°C回火時間的變數（10到60分鐘）中，強度最佳的沃斯回火時間為30分鐘。
為了解雙環型試片受到缺口效應（Notch Effect）影響的程度，本研究另外製作球墨鑄鐵板狀拉伸試片，與經過相同沃斯回火熱處理條件處理的雙環型試片進行比較。實驗結果顯示350°C回火的雙環型試片受到缺口效應的影響最低，其拉伸強度與標準試片拉伸強度的差距較小。
在本研究各回火條件中，沃斯回火球墨鑄鐵雙環型試片的最佳回火條件為350°C回火30分鐘，平均強度約為880 MPa；其原因在於基地組織以強度較佳的下變韌體為主，加上適量的殘留沃斯田體延緩破壞發生，使得雙環型試片受圓孔應力集中效應降低，而有較佳強度表現。

This study is focused on the properties of eyeglass type austempered ductile iron (ADI) specimen. The eyeglass type specimen is used in transmission systems, and the essential properties are good hardness and tensile strength. But the notch effect would cause the mechanical performance of eyeglass type specimen becoming worse. The base of ADI is bainite, which is good combination of hardness, strength and ductility. In this study, the ductile iron casting was shaped into eyeglass type dimension. The ductile iron also processed into thin standard specimen, in order to be a contrast. The specimens were austenized at 930°C for 30 minutes, followed by a quench to salt bath, which the austempering temperature is 250°C, 300°C, 350°C, 400°C, and holding for 30 minutes. The results showed that the best tensile strength of eyeglass specimen was austempered at 350°C, but the best austemperig temperature for standard specimen was 300°C. The reason is that the factor which affected the standard specimen was the base strength. In eyeglass type specimen, the factors were not only the base strength but also the amount of retained austenite. When austempered at 350°C, lower bainite structure supplied good strength, and enough amount of retained austenite to reduce the notch effect. In this study, austempering temperature at 350°C is the best temperature parameter for eyeglass type specimen.

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