本研究係使用高轉速摩擦攪拌銲接設備，使用碳化鎢圓棒的銲接工具在正向負荷(150~500 N)、主軸轉速(6000~24000 rpm)、銲接時間(10~60 sec)與進給速度(0~2 mm/sec)等銲接參數條件下，對薄低碳鋼板摩擦攪拌搭接，從銲道表面形貌、表面輪廓、溫度變化與拉剪破壞力等結果，探討薄低碳鋼板之銲接特性與銲接機制。
依據定點銲接實驗結果作為進給銲接參數規劃參考，經由實驗得知，在主軸轉速18000 rpm與正向負荷300~500 N於進給速度1~2 mm/sec及主軸轉速12000~24000 rpm與正向負荷400 N於進給速度1~2 mm/sec之銲接條件下可得到鍵結良好且表面至多僅凸起0.06 mm之平整銲道的銲接效果，其中接合強度最高可較母材提升約1.26倍。
由實驗結果探討正向負荷(Fd)、主軸轉速(Ns)與進給速度(ƒ)對拉剪破壞力(Ff)之關係，可求出經驗公式為Ff=0.0408‧Fd^0.2391∙Ns^0.2325∙ƒ^0.1041 。由公式得知Ff與Fd‧Ns‧ƒ呈正比關係，其中主軸轉速與正向負荷對銲道之拉剪破壞力較進給速度對銲道之拉剪破壞力影響的程度大，而正向負荷之影響又較主軸轉速敏感，由此結果可作為薄鋼板之摩擦攪拌銲接參考。

In this study, friction stir lap welding (FSLW) of thin steel sheets was conducted with high rotating speed and constant load. Using a pin-less tool made from tungsten carbide (WC) with 6 mm diameter, the welding characteristics and welding mechanism of thin steel sheets were investigated under different operation conditions, such as the load (150~500 N), the rotating speed (6000~24000 rpm), the welding time (10~60 sec)and the feeding speed (0~2 mm/sec). Effects of load, rotating speed, welding time and feeding speed on the appearance, surface profile, shear fracture load, and interface temperature between the tool and steel sheet were investigated.
Based on the results of spot welding, the operation conditions were selected for the feeding welding. Experimental results showed that the optimum lap condition for thin steel sheets at the load of 300~500 N, rotating speed of 18000 rpm with the feeding speed 1~2 mm/s and the load of 400 N, rotating speed of 12000~24000 rpm with the feeding speed 1~2 mm/s, where the appearance was smooth with the protrusion no more than 0.06 mm. The shear strength is about 1.26 times as strong as that for the base metal at the load of 500 N, rotating speed of 18000 rpm, and feeding speed 2 mm/s.
Based experimental results, the empirical equation of maximum shear fracture load (Ff) suitable for thin steel sheets of the FSLW process is derived in terms of load (Fd), rotating speed (Ns), feeding speed (ƒ) as Ff=0.0408∙Fd^0.2391∙Ns^0.2325∙ƒ^0.1041. This formula indicated that Ff is proportional to the Fd, Ns and ƒ. Moreover, the influence of load on shear fracture load is greater than rotating speed, and the influence of rotating speed is greater than feeding speed.

學位論文審定書 i
誌謝 ii
摘要 iii
Abstract iv
目錄 v
圖次 vii
表次 xi
第一章 緒論 1
1.1前言 1
1.2文獻回顧 3
1.3研究目的 8
第二章 實驗設備與實驗方法 9
2.1摩擦攪拌銲接設備 9
2.1.1高速主軸裝置 10
2.1.2進給裝置 10
2.1.3氣壓裝置 11
2.2表面粗度量測儀 13
2.3拉力試驗機 13
2.4紅外線熱像儀 14
2.5實驗試片 15
2.5.1實驗試片材料特性 15
2.5.2實驗試片幾何形狀 15
2.6銲接工具 16
2.6.1銲接工具材料特性 16
2.6.2銲接工具幾何形狀 17
2.7實驗治具設計與材料 17
2.8實驗方法 19
2.8.1實驗前處理 19
2.8.2實驗參數規劃 19
2.8.3銲接位置 20
2.8.4實驗步驟 20
2.9 銲接過程表面溫度量測 21
2.10 銲道表面輪廓量測 22
2.11 拉剪破壞試驗 22
2.12 顯微組織觀察 24
2.13 微硬度試驗 25
2.14 實驗流程 26
第三章 結果與討論 27
3.1定點銲接實驗 27
3.1.1表面粗糙度影響 27
3.1.2時間影響 30
3.1.3正向負荷影響 33
3.1.4主軸轉速影響 36
3.1.5熱暈尺寸、銲接溫度與拉剪破壞力之關係 39
3.1.6主軸轉速與正向負荷對拉剪破壞力之關係 41
3.2進給銲接實驗 43
3.2.1正向負荷與進給速度之影響 44
3.2.2主軸轉速與進給速度之影響 50
3.2.3主軸轉速、正向負荷與進給速度對銲道拉剪破壞力之關係 56
3.3顯微組織分析 58
3.4微硬度分佈 63
第四章 結論與未來展望 66
4.1結論 66
4.2未來展望 67
參考文獻 68
附錄 複線性迴歸分析步驟 71

[1] W. M. Thomas, E. D. Nicholas, J. C. Needham, M. G. Murch, P. Templesmith, and C. J. Drawes, “Friction stir butt welding”, G B Patent Application No. 9125978.8, Dec. 1991; S.S. Patent No. 5460317, 1995.
[2] W. M. Thomas, E. D. Nicholas, R. E. Dolby, C. J. Jones, and R. H. Lilley, “Friction plug extrusion”, International Patent PCT / GB92 /01540.21.8.92.
[3] S. W. Williams, “Welding of airframes using friction stir”, Air & Space Europe Vol. 3 (2001) 64–66.
[4] W. M. Thomas, E. D. Nicholas, “Friction stir welding for the transportation industries”, Materials and Design Vol. 18 (1997) 269–273.
[5] M. R. Johnson, “Friction stir welding takes off at boeing”, Welding Journal Vol. 78 (1999) 35–39.
[6] A. Kh. Hussain, E. P. Koorapati, K. V. Kumar, S. Yousufuddin, “Fatigue Life Evaluation of Friction Stir Welded 7075-T651 Aluminum Alloy Joints”, International Journal of Advanced Design and Manufacturing Technology.
[7] O. T. Midling, E. J. Morley and A. Sandvik, “Friction stir welding”, World Intellectual Property Organization Patent Application No. 95907888.2, 1995.R.
[8] R. S. Mishra and Z. Y. Ma, “Friction stir welding and processing”, Materials Science and Engineering Vol. 50 (2005) 1-78.
[9] W. M. Thomas, P. L. Threadgill, and E. D. Nicholas, ”Feasibility of friction stir welding steel”, Science and Technology of Welding and joining Vol. 4 (1999) 365-372.
[10] Ling Cui, Hidetoshi Fujii, Nobuhiro Tsuji and Kiyoshi Nogi, “Friction stir welding of a high carbon steel”, Scripta Materialia Vol. 56 (2007) 637-640.
[11] A. K. Lakshminarayanan, V. Balasubramanian and M. Salahuddin, ”Microstructure, tensile and impact toughness properties of friction stir welded mild steel”, Journal of Iron and Steel Research, International Vol. 17 (2010) 68-74.
[12] D. A. Wang, C. W. Chao, P. C. Lin, J. Y. Uan, “Mechanical characterization of friction stir spot microwelds”, Journal of Materials Processing Technology Vol. 210 (2010) 1942–1948.
[13] K. Aota and K. Ikeuchi, “Development of friction stir spot welding using rotating tool without probe and its application to low-carbon steel plates”, Welding International Vol. 23 (2009) 572-580.
[14] Y. F. Sun, H. Fujii, N. Takaki, Y. Okitsu,”Microstructure and mechanical properties of mild steel joints prepared by a flat friction stir spot welding technique”, Materials and Design Vol. 37 (2012) 384-392.
[15] M. Ghosh, K. Kumar, R.S. Mishra, ”Friction stir lap welded advanced high strength steels: Microstructure and mechanical properties”, Materials Science and Engineering A Vol.528 (2011) 8111-8119.
[16] H. Fujii, R. Ueji, Y. Takada, H. Kitahara, N. Tsuji, K Nakata, K. Nogi,”Friction stir welding of ultrafine grained interstitial free steels”, Materials Transactions Vol.47 (2006) 239-242.
[17] D.H Choi, C.Y. Lee, B.W. Ahn, J.H. Choi, Y.M. Yeon, K. Song, H.S. Park, Y.J. Kim, C.D. Yoo, S.B. Jung, “Frictional wear evaluation of WC-Co alloy tool in friction stir spot welding of low carbon steel plates”, Inernational. Journal of Refractory Metals & Hard Materials Vol.27 (2009) 931-936.
[18] K. Aota and K. Ikeuchi, “Friction stir welding of aluminium lap joint by tool without probe”, Welding International Vol. 24 (2010) 197-205.
[19] H. Fujii, L. Cui, N. Tsuji, M. Maeda, K. Nakata, K. Nogi, “Friction stir welding of carbon steel”, Materials Science and Engineering A Vol.429 (2006) 50-57.
[20] George F. Vander Voort, “Metallography, principles and practice”, ASM International, (1984) 632.
[21] 劉鑑德，”使用無探針工具於摩擦攪拌銲接之接合特性的研究”，中山大學機械與機電工程學系研究所博士論文，(2013) 14-20。