本研究探討高矽鋼在沃斯回火過程的相變化及機械性質，包括碳、矽含量對高矽鋼相變化的影響及拉伸試驗、衝擊試驗和硬度試驗等。研究中所用的沃斯回火時間是依據高矽鋼在沃斯回火過程中電阻係數曲線變化而定。
研究結果顯示，沃斯回火高矽鋼的機械性質將獲得大幅提升，特別是在伸長率方面較之沃斯回火球墨鑄鐵更是出色。沃斯回火溫度對機械性質影響很大，高矽鋼在較低的沃斯回火溫度會有較高的強度及硬度，但是延性、韌性會降低。用X-ray繞射來量測殘留沃斯田鐵，顯示在低溫沃斯回火後的殘留沃斯田鐵體積分率較少。也顯現殘留沃斯田鐵體積分率會影響高矽鋼的機械性質。

In this study the microstructure and mechanical properties of austempered high silicon steels were investigated, including the effect of carbon and silicon contents on austempering, ultimate tensile strength, 0.2% offset yielding strength, elongation, impact energy and hardness. The austempering time located withing the processing windows were derived from the electrical resistivity curves during austempering .
Results of this study show that the mechanical properties of austempered high silicon steels will be promoted in a large amount, when compared with austempered ductile iron especially in elongation. The mechanical properities were sensitive to austempering temperature, at lower austempering temperature, high silicon steels will obtain higher strength and hardness but lower ductility and impact toughness. X-ray diffraction was used to measure the fractions of retained austenite, and show that steels with lower austempering temperature had low fractions of retained austenite. This also show that the mechanical properties of austempered high silicon steels is effected by the fraction of retained austenite.

第一章 前言...................................1
第二章 原理及文獻探討.........................5
2.1 高矽鋼的沃斯回火反應...................5
2.2 沃斯回火處理...........................6
2.3 高矽鋼的變態結.........................7
2.3.1 高矽鋼的變韌組織.......................8
2.3.2 由上變韌鐵到下變韌鐵間的轉換過程.......9
2.3.3 高矽鋼的相變化過程.....................9
2.3.4 沃斯肥粒鐵的形成......................10
2.4 製程窗間..............................11
2.5 影響高矽鋼顯微組織及機械性質的因素....12
2.5.1 沃斯田鐵化溫度、時間的影響............12
2.5.2 沃斯回火溫度及時間....................13
2.5.3 合金元素的影響........................14
2.5.4 貿量效應..............................15
2.6 顯微組織及機械性質的關係..............16
2.7 殘留沃斯田鐵量的量測..................16
第三章 實驗方法..............................27
3.1 實驗流程..............................27
3.2 材料的準備及分析......................27
3.3 均質化、鍛造及退火處理................28
3.4 機械性質量測試片之沃斯回火時間選取....28
3.5 鹽浴爐溫度均勻度......................29
3.6 機械性質的量測........................31
3.6.1 衝擊試驗..............................31
3.6.2 拉伸試驗..............................31
3.6.3 硬度試驗..............................32
3.7 殘留沃斯田鐵量的量測..................32
3.7.1 試片準備..............................32
3.7.2 殘留沃斯田鐵的量測及計算..............33
3.8 金相觀察..............................33
3.9 破斷面觀察............................34
第四章 結果與討論............................48
4.1 高矽鋼的正常化組織及性質..............48
4.2 機械性質..............................48
4.2.1 310℃沃斯回火.........................48
4.2.2 370℃沃斯回火.........................49
4.2.3 400℃沃斯回火.........................49
4.3 與ADI的比較...........................50
4.4 顯微組織..............................51
4.5 破斷面分析............................53
4.6 碳含量對機械性質的影響................54
第五章 結論..................................72
參考文獻..............................73
作者簡介..............................76
授權書................................77

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