臺灣博碩士論文加值系統

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

1.R. B. Gundlach and J. F. Janowak, “A Review of Austempered Ductile Iron Metallurgy,” 1st. Conf. on ADI, Chicago, Illinois, pp.1-12(1984).
2.H. Bayati and R. Elliott, “Role of Austenite in Promoting Ductility in an Austempered Ductile Iron,” Materials Science and Technology, Vol. 13, No. 2, pp.319-325(1997).
3.J. F. Janowak and R. B. Gundlach, “Development of A Ductile Iron for Commercial Austempering,” AFS Trans, Vol. 93, pp.453-462(1985).
4.L. C. Chang, “Bainite Transformation Temperature in High-Silicon Steels,” Metallurgical and materials transactions, Vol. 30A, No. 4 pp.909-916(1999).
5.J. F. Janowak and R. B. Gundlach, “Technical Advances in Cast Iron Metallurgy,” AFS International Cast Metals Jouranl, Vol. 74, pp.28-42(1981).
6.R. C. Voigt and R. Bendaly and J. F. Janowak, “Development of Austempered High Silicon Cast Steels,” AFS Trans, Vol.93, pp.453-462(1985).
7.A. Barbacki and E. Mikolajski, “Optimization of Heat Treatment Conditions for Maximum Toughness of High Strength Silicon Steel,” Journal of Materials Processing Technology, Vol.78, No. 1, pp.18-23(1998).
8.J. Mallia and M. Grech, “Effect of Silicon Content on Impact Properities of Austempered Ductile Iron,” Materials Science and Technology, Vol. 13, No. 5, pp.408-415(1997).
9.B. V. Kovacs, Sr. “Austempered Ductile Iron : Fact and Fiction,” Modern Casting, Vol.80, No. 3, pp.38-41(1990).
10.L. R. Jenkins and R. D. Forrest, Metals Handbook, Vol.1, 10thedition, America Society for Metals, Park, Ohio, pp.33-35(1990).
11.Y. J. Park, R. B. Gundlach and J. F. Janowak, “Monitoring the Bainite Reaction During Austempering of Ductile Iron and High Silicon Cast Steel by Resistivity Measurement,” AFS Trans, Vol.95, pp.411-416(1987).
12.H. K. D. H. Bhadeshia, “Some Phase Transformations in Steels,” Materials Science and Technology, Vol.15, No.1, pp.22-29(1999).
13.T. Takahashi, T. Abe and S. Tada, “Effect of Bainite Transformation and Retained Austenite on Mechanical Properties of Austempered Spheroidal Graphite Cast Steel,” Metallurgical and Materials Transactions A, Vol. 27A, No.6, pp.1589-1598(1996).
14.G. Nadkarni, S. Gokhale and J. D. Boyd, “Elevated Temperature Microstructural Stability of Austempered Ductile Irons,” AFS Trans, Vol.104, pp.985-994(1996).
15.王主恩，「高矽鑄鋼沃斯回火相轉變之研究」，碩士論文，國立台灣科技大學，台北(2000)。
16.黃俊仁，「利用機械性質探討含銅及鎳球墨鑄鐵之高溫沃斯回火製程窗間」，碩士論文，國立台灣科技大學，台北(1996)。
17.溫東成，「麻田散鐵影響沃斯回火球墨鑄鐵機械性質之研究」， 博士論文，國立台灣科技大學，台北(1999)。
18.M. Bahmani and R. Elliott, “Effects of Pearlite Formation on Mechanical Properties of Austempered Ductile Iron,” Materials Science and Technology, Vol.10, No.12, pp.1068-1072(1994).
19.K. Tsuzaki, A. Kodai and T. Maki, “Formation Mechanism of Bainitic Ferrite in an Fe-2 Pct Si-0.6 Pct C Alloy,” Metallurgical and Materials Transaction A, Vol 25A, No.9, pp.2009-2016(1994).
20.L. C. Chang, “Mechanism of Banite Formation in Steels,” Chinese Journal of Materials Science, Vol. 30, No. 3, pp.151-164(1998).
21.M. Hillert, “Diffusion in Growth of Bainite,” Metallurgical and Materials Transactions A, Vol. 25A, No.9, pp.1957-1966(1994).
22.陳建同，「沃斯回火球墨鑄鐵相轉變動力學之研究」，博士論文，國立台灣科技大學，台北(1999)。
23.H. K. D. H. Bhadeshia and J. W. Christian, “Bainite in Steels,” Metallurgical Transactions A, Vol. 21A, No.4, pp.767-797(1990).
24.H. K. D. H. Bhadeshia and D. V. Edmonds, “The Bainite Transformation in a Silicon Steel,” Metallurgical Transactions A, Vol. 10A, No.7, pp.895-907(1979).
25.G. Spanos, “The Fine Structure and Formation Mechanism of Lower Bainite,” Metallurgical and Materials Transactions A, Vol. 25A, No.9 pp.1967-1980(1994).
26.鄭朝旭，「沃斯肥粒鐵變態的研究」，鑄工，第21卷，第84期，第59-73頁(1995)。
27.B. T. Sim and R. Elliott, “Relationship between Mechanical Properties and Structure in Austempered Alloyed Compacted Graphite Cast Iron,” Materials Science and Technology, Vol. 14, No.3 pp.241-244(1998).
28.林本源，「合金元素對球墨鑄鐵沃斯回火相轉變的影響」，博士論文，國立台灣科技大學，台北(1995)。
29.J. Aranzabal, I. Gutierrez, J. M. Rodriguez-Ibabe and J. J. Urcola, “Influence of the Amount and Morphology of Retained Austenite on the Mechanical Properties of an Austempered ductile iron,” Metallurgical and Materials Transactions, part A, Vol.28A, No.5 pp.1143-1156(1997).
30.N. Darwish and R. Elliott, “Austempering of Low Manganese Ductile Irons Part 1 Processing Window,” Materials Science and Technology, Vol.9, No.7, pp.572-585(1993).
31.H. Bayati and R. Elliott, “Influence of Matrix Structure on Physical Properties of an Alloyed Ductile Cast Iron,” Materials Science and Technology, Vol. 15, No.3, pp.265-277(1999).
32.N. Darwish and R. Elliott, “Austempering of Low Manganese Ductile Irons Part 2 Processing Window,” Materials Science and Technology, Vol.9, No.7, pp.586-602(1993).
33.S. K. Liu, L. Yang, D. G. Zhu and J. Zhang, “The Influence of the Alloying Elements upon the Transformation Kinetics and Morphologies of Ferrite Plates in Alloy Steels,” Metallurgical and Materials Transactions A, Vol.25A, No.9, pp.1991-2000(1994).
34.W. J. Dubensky and K. B. Rundman, “An Electron Microscope Study of Carbide Formation in Austempered Ductile Iron,” AFS Trans, Vol.93, pp.389-394(1985).