在棒材擠製的過程中，擠錠表層雜質，諸如氧化膜與偏析層，會隨著擠製過程流入成品造成缺陷。而遭受表皮層侵入之缺陷部位強度減弱，故須將其切除之，因而造成產品良率降低。
本研究使用有限元素分析進行擠製模擬，探討產品擠製比、主模斜角、擠錠長度及表皮層厚度等加工參數對擠製後產品包料長度之影響。從一系列之解析結果可獲得消除包料時之最佳主模斜角。
最後進行擠製實驗，將實驗數據代入解析程式，所獲得之包料長度與實驗值進行比較，以驗證解析模式之適用性。

During a rod extrusion process, the oxidation layer and the segregation layer at the billet surface are possibly drawn inside the billet and become one part of the product, which portion with surface-permeation has to be cut off and results in a low productivity of the extrusion process. In this paper, the mechanism of permeation of the oxidation and segregation layers at the billet surface is explored using a finite element analysis. The effects of various extrusion conditions, such as extrusion ratio, inclination angle, billet length, the thickness of oxidation layer, etc., on the length of the portion with surface permeation are discussed systematically. Optimal inclination angles for a free surface-permeation product under different extrusion ratios are found out. An empirical equation for the optimal inclination angles is also proposed. Finally, experiments of extrusion of aluminum rods are conducted to validate the analytical model proposed.

總目錄
目錄 II
表目錄 IV
圖目錄 V
摘要 X
Abstract XI


目錄
第一章 緒論 1
1-1 前言 1
1-2 A6061（鋁-矽-鎂）鋁合金成份及特性 5
1-3 氧化膜的形成與種類 6
1-4 擠製加工成形技術之簡介 8
1-4-1 直接擠製法（Direct Extrusion） 8
1-4-2 間接擠製法（Indirect Extrusion） 9
1-5 關於改善包料現象之習知技術之敘述及缺點 10
第二章 有限元素解析 13
2-1 有限元素法之基本理論 13
2-2 塑性成形之FEM 力學模式分析 14
2-3 有限元素分析軟體DEFORMTM之簡介 16
2-4 模擬參數之設定 20
2-5 解析結果及討論 23
2-5-1 主模斜角（Inclination angle）對包料現象之影響及改善 24
2-5-2 擠錠初始表皮層厚度（to）對包料現象之影響及探討 35
2-5-3 剪摩擦因子（m）對包料現象之影響及探討 35
第三章 鋁合金A6061擠製加工之分析及實驗 37
3-1 實驗規劃 37
3-2 實驗結果 39
3-2-1 金相觀察 39
3-2-2 成份分析 62
3-2-3 硬度試驗 66
3-2-4 擠製實驗 68
3-3 實驗結果與解析結果之比較 71
3-3-1 Pocket Die之解析結果 71
3-3-2 Flat-taper-flat Die之解析結果 80
3-3-3 實驗與解析及分析誤差原因 84
第四章 結論 92
4-1 研究成果總結 92
4-2 未來展望 94
參考文獻 95

[1]H. Yoshida, Y. Sakaida, T. Nakamura, K. Hayakawa, K. Takahashi and Y. Awaki,“Shaping of helical gear by cold extrusion through expansion of inner diameter of workpiece”, The Proceedings of the 59th Japanese Joint Conference for the Technology of Plasticity, pp.105–106, 2008.
[2]M. Nikawa and M. Shiraishi, “Extrision process for producing the hollow shaft with helical tooth in the outside/inside”, The Proceeding of the 59th Japanese Joint Conference for the Technology of Plasticity, pp.113–114, 2008.
[3]K. Suzuki, M. Hoshino and Y. Uchida, “Examination of orthogonal channel extrusion method－A new method of extrusion of fuel cell separator using orthogonal channel I”, Journal of the Japan Society for Technology of Plasticity (JSTP), Vol. 50, No. 576, pp.49–53, 2009.
[4]H. Mori and M. Noda, “塑性加工技術から見た鉄道車体技術の遷移”,
Journal of the Japan Society for Technology of Plasticity (JSTP), Vol. 50, No.
576, pp.9–12, 2009.
[5] R. H. Stevens, “ ASM Handbook: Metallographic Techniques and
Microstructures：Specific Metals and Alloys”, American Society for Metals,
Metals Park, Ohio, 1999.
[6] T. Murai, S. Matsuoka, S. Miyamoto, Y. Oki, S. Nagao and H. Sano, “Effects
of zinc and manganese contents on extrudability of Mg–Al–Zn alloys”, Journal
of Japan Institute of Light Metals, Vol.53, No.1, pp.27–31, January 2003.
[7] S. Fox and J. Campbell, “Visualisation of Oxide Film Defects During
Solidication of Aluminum Alloys”, Scripta mater：43, pp.881–886, 2000.
[8] Y. Takagi, K. Miyahara, R. Haginaka, and S. Masa, “Cause of streak that
occurred after surface treatment in 6063 aluminum alloy extruded section”,
Journal of Japan Institute of Light Metals, Vol.50, No.9, pp.441–445, 2000.
[9] T. Minoda and H. Yoshida, “Effect of grain boundary characteristics on
intergranular corrosion resistance of 6061 aluminum alloy extrusion ” ,
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials
Science, Vol. 33, No. 9, pp.2891–2898, September 2002.
[10] T. Minoda and H. Yoshida, “ Effect of microstructures on intergranular
corrosion resistance of 6061 aluminum alloy extrusions” Journal of Japan
Institute of Light Metals, Vol. 49, No. 11, pp.548–552, November 1999.
[11] T. Minoda and H. Yoshida, “Effect of microstructure on intergranular corrosion
resistance of 6061 alloy extrusion”, Materials Science Forum, Vol. 331, 2000.
[12] V. Otto, “Fundamentals of extrusion”, Candy Industry, 2008.
[13] Totten,E.G., D.S. MacKenzie, “Handbook of Aluminum”, Marcel Dekker,
Inc.,New York, Vol.1, p.385–480, 2003.
[14] M. Tokizawa, N. Takatsuji, K. Murotani and K. Matsuki, “Studies on the Metal
Flow and Die Shapes in Extrusion of Al–4%Mg Alloy”, Journal of the Japan
Society for Technology of Plasticity (JSTP), Vol.23, No.256, pp.437–443, 1982.
[15] N. Takatsuji, M. Tokizawa, K. Murotani, K. Matsuki and S.Murata,
“Improvement of extrusion yield examined from plastic flow of billet surface
layer”, Journal of the Japan Society for Technology of Plasticity (JSTP), Vol.28,
pp.818–824, 1987.
[16] N. Takatsuji, M. Tokizawa, K. Murotani, K. Matsuki and T. Yamabayashi,
“Effects of Die Angle on Pressure Distribution at Internal Surface of Die Block
and Extrudability of Billet in Hot Extrusion”, Journal of the Japan Society for
Technology of Plasticity (JSTP), Vol.29, No.325, pp.161–165,1988.
[17] M. Tokizawa, N. Takatsuji, K. Murotani, T. Nakamura and Y. Goto, “Effects of
Die Angle on Metal Flow and Pressure Distribution on Internal Surface of
Container in Hot Indirect Extrusion”, Journal of the Japan Society for
Technology of Plasticity (JSTP), Vol.30, No.347, pp.1675–1681,1989.
[18] K. Takeuchi, “Simulation of metal flow in billets during extrusion by plasticine”,
Journal of Japan Institute of Light Metals, Vol.39, No.10, pp.693–698, 1989.
[19] W.D. Finkelnburg and G. Scharf, “Some investigations on the metal flow during
extrusion of al alloys”, Proceedings of Fifth International Aluminum Extrusion
Technology Seminar, Chicago, Vol.1, pp.475–484, 1992.
[20] W. Libura and J. Zasadzinski, “The Strain Gradient Effect on Microstructure and
Properties of Extruded Aluminium Alloys”, Proceedings of Fifth International
Aluminum Extrusion Technology Seminar, Chicago, Vol.1, pp.487–494, 1992.
[21] M. Lefsta, O. Reiso and V. Johnsen, “Flow of the Billet Surface in Aluminum
Extrusion”, Proceedings of Fifth International Aluminum Extrusion Technology
Seminar, Chicago, Vol.1, pp.503–517, 1992.
[22] H. Valberg and T. Loeken, “Formation of the Outer Surface Layers of the Profile
In Direct and Indirect Extrusion”, Proceedings of Fifth International Aluminum
Extrusion Technology Seminar, Chicago, Vol.1, pp.529–550, 1992.
[23] N.Takatsuji, M. Tokizawa, S. Murakami, K. Muritani, K. Matsuki and K. Yuasa ,
“Effects of Die Shapes on Welding Strength of Extruded Pipes by Port-Hole
Die(Improvement in Quality of Hollow Extrusions 1) ”, Journal of the Japan
Society for Technology of Plasticity (JSTP), Vol.36, No.414, pp.731–736,1995.
[24] J. Hou, “Inward Flow of Surface Materials at Back–Ends of Billets During
Al-Extrusion, Part1:A Finite Element Model”, Journal of Manufacturing Science
and Engineering, Vol.121, pp.321–327, August 1999.
[25] J. Hou, U. Stahlberg and B. Bengtsson, “Inward Flow of Surface Materials at
Back–Ends of Billets During Al–Extrusion, Part2:Influence of Process
Parameters”, Journal of Manufacturing Science and Engineering, Vol.121,
pp.328–335, August 1999.
[26] Y.T. Kim, K. Ikeda, “Flow behavior of the billet surface layer in porthole die
extrusion of aluminum”, Metallurgical and Materials Transactions A, Vol.31A,
pp.1635–1643, 2000.
[27] L. Hansen and M. Lefstadt, “Billet surface flow in aluminium extrusion using
half–moon dies”, Aluminium 76, pp.138–141,2000.
[28] H. Sano, T. Ishikawa and Y. Yoshida, “Study on the metal flow in extruded billet”,
Sumitomo Light Metal Technical Reports, Vol.45, No.1, pp.493–496, 2004.
[29] Dixon. Bill, “Billet surface flow during extrusion of aluminium alloys”,
Aluminium International Today, Vol.16, No.2, pp.44–46+50, March/April 2004.
[30] Z. Peng and T. Sheppard, “A study on material flow in isothermal extrusion by
FEM simulation”, Modelling and Simulation in Materials Science and
Engineering, Vol.12, No.5, pp.745–763, September 2004.
[31] T. Ishikawa, H. Sano, Y. Yoshida, N. Yukawa, J. Sakamoto and Y. Tozawa,
“Effect of extrusion conditions on metal flow and microstructures of aluminum
alloys”, Annals of the CIRP, Vol.55, pp.275–278, 2006.
[32] T. Hatzenbichler, B. Buchmayr and A. Umgeher, “A numerical sensitivity study
to determine the main influence parameters on the back–end defect”, Journal of
Materials Processing Technology, Vol.182, No.1–3, pp.73–78, Febrary 2 2007.
[33] M. Schikorra, L. Donati, L. Tomesani and M. Kleiner, “The role of friction in the
extrusion of AA6060 aluminum alloy, process analysis and monitoring”, Journal
of Materials Processing Technology, Vol.191, No.1–3, pp.288–292, 2007.
[34] H. Sano, T. Ishikawa, N. Yukawa, Y. Yoshida and T. Kaneko, “Effect of extrusion
mode and die shape on billet skin behavior in aluminum extrusion”, Journal of
Japan Institute of Light Metals, Vol. 58, No. 5, pp.183–188, 2008.
[35] H. Sano, T. Ishikawa, N. Yukawa, Y. Yoshida, T. Kaneko and J. Sakamoto,
“Effect of back end lubricant conditions on billet skin behavior in direct
extrusion”, Journal of Japan Institute of Light Metals, Vol. 58, No.5, pp.189–193,
2008.
[36] T. Uchiyama, M. Takaya, H. Naoi, F. Ikata, Y. Kuwahara, “Investigation of Hot
Bulge Forming for Magnesium Alloy’s Tees of Pipe Joints”, The Proceedings of
the 56th Japanese Joint Conference for the Technology of Plasticity, pp.129–130,
2005.
[37] Y.M. Hwang and C.Y. Shen, “Analysis of plastic flow and die design during
extrusion of CPU heat sinks”, Journal of Materials Processing Technology 201,
pp.174-178, 2008.
[38] N.C.W. Kuijpers, Kool, W.H. and Van der Zwaag, “DSC study on Mg–Si phases
in as cast AA6xxx”, Materials Science Forum, Vol.396–402, No.2,
pp.675–680,2002.
[39] M.Tadashi and Y.Hideo, “Effect of microstructures on intergranular corrosion
resistance of 6061 aluminum alloy extrusions”, Journal of Japan Institute of
Light Metals, Vol.49, No.11, pp.548–552, 1999.
[40] M.Tadashi, H. Hideya and Y. Hideo, “Mechanism of pick-up formation on 6063
aluminum alloy extrusions”, Journal of Japan Institute of Light Metals, Vol.49,
No.6, pp.253–257, June 1999.
[41] N. C. Parson, J. D. Hankin and K. P. Hicklin, “Al–Mg–Si alloy with good
extrusion properties”, US-patent, 2002.
[42] X. Duan and T. Sheppard, “Simulation and control of microstructure evolution during hot extrusion of hard aluminium alloys”, Materials Science and
Engineering A, Vol.351, No.1–2, pp.282–292, 2003.
[43] T. Murai, “Extrusion of magnesium alloys”, Journal of Japan Institute of Light
Metals, Vol.54, No.11, pp.472–477, 2004.
[44] S.Okaniwa, “Metal flow in extruded products of aluminum”, Journal of Japan
Institute of Light Metals, Vol.36, No.8, pp.507–513, 1986.
[45] Q. Li, C. Harris and M.R. Jolly, “Finite element modelling simulation of
transverse welding phenomenon in aluminium extrusion process”, Materials and
Design, Vol.24, No.7, pp.493–496, October 2003.
[46] S. Kaneko, K. Murakami and T. Sakai, “Effect of the extrusion conditions on
microstructure evolution of the extruded Al–Mg–Si–Cu alloy rods”, Materials
Science and Engineering A, Vol.500, pp.8–15, 2009.