溫成形實驗平台建立與實驗流程

本 研 究 之 V 型 彎 曲 成 形 沖 壓 為 建 立 在 實 驗 室 材 料 拉 伸 機 (MTS810)之平台上，其中模具設計搭配介面熱傳實驗中所使用的通 水路之冷卻塊，將可進行之實驗為板材之各溫度區間之冷、溫、熱成 形，其中各模具部件為圖 5.31 所示，將其架設在實驗室材料拉伸機 (MTS810)並可進行沖壓，如圖 5.32。其實驗流程為將板件放置加熱爐 中加熱至欲探討溫度，由於析岀強化之鋁合金板材如A6061-T6 在高 溫下持溫過久時間將導致強度下降，因此需考慮其加熱至溫度穩態時 間，而加熱至溫度穩態時間則透過板材插入熱電偶放置加熱爐進行溫 度量測，如圖 5.33，最後列出 150 度、250 度、350 度各自溫度歷程，

圖 5. 33 V 型彎曲實驗模具

圖5. 34V 型彎曲實驗模具架設於材料拉伸機圖

圖 5. 35 加熱爐與熱電偶量測板材升溫曲線

圖5. 36 150 度溫度歷程

圖5. 37 250 度溫度歷程

圖5. 38 350 度溫度歷程

表5. 3 三種溫度區間的溫度穩態時間 板材欲加熱溫度(℃) 溫度達穩態時間(s)

150 800

250 900

350 1000

本論文於此節探討不同溫成形溫度下對應鋁合金板材回彈改善 現象， 採用上述建立之 V 型彎曲模具進行實驗，沖頭圓角分別選用 最大圓角 R11 及 R6，溫度採用三種溫度區間，分別為 150 度、250 度、350 度，由本論文第四章 4.2.1 節之 V 型彎曲成形實驗可得知 A6061-T6 因強度較 A6061-O 高，其回彈角度明顯地比 A6061-O 來得 嚴重，然而以汽車結構件應用需求而言，A6061-T6 較能滿足其強度 需求，因此T6 更有探討回彈改善之價值，故此節將針對 A6061-T6 進行溫成形實驗探討。預計比較 A6061-A6061-T6 在不同溫成形製程條件 下，對回彈改善的趨勢，另外也將板件分成壓延方向平行板材長軸方 向(longitude direction, LD)以及垂直板材長軸方向(transverse direction, TD)，探討壓延方向對溫成形角度的影響差異。如圖 5.37 為 V 型彎曲

圖5. 39 V 型彎曲實驗過程

圖 5. 40 V 型彎曲實驗板件成品

圖 5. 41 GOM ATOS 逆向掃描

圖5. 42 GOM Inspect 回彈分析

可得知沖頭圓角R11 的溫成形條件下，雖然與沖頭圓角 R6 之條

room 150 250 350

回彈角度(度)

room 150 250 350

回彈角度(度)

板材溫度(°C)

A6061-T6之溫成形回彈改善趨勢

LD TD

圖5. 46 A6061-T6 在沖頭圓角 R11 與 R6 溫成形回彈改善比率

因文獻[42]可知，溫成形製程可使得鋁合金 A6061-T6 的成形極限提 升，另一方面也可以抑制回彈現象。

150 250 350

改善比率(%)

板材溫度(°C)

A6061-T6之溫成形回彈改善比率

R11 R6

第六章 結論

立鋁合金A6061-O 與 A6061-T6 之材料模型，包括 Hill48 與 Barlat91 等降伏準則搭配 Yoshida 硬化準則。使用求得之材料模型進行 V 型彎 曲與 U 型帽狀引伸之模擬，並且搭配相對應之成形實驗進行模擬驗 證，進而探討最適合鋁合金A6061-O 與 A6061-T6 之材料模型。以 V 型彎曲而言，各材料模型預測之回彈量皆與實驗達到準確預測。而以 U 型帽狀引伸而言，則是以考慮到包辛格效應之 Yoshida 模型搭配

Hill48 或 Barlat91 兩材料模型對於預測 A6061-T6 側壁捲曲有著較準 確的預測。後續本論文使用Barlat91 搭配 Yoshida 模型進行探討鋁合 金 A6061-T6 之回彈改善方法。使用姚順偉[29]的阻料條設計流程探 討屬於鋁合金A6061-T6 之阻料條設計，先探討合適的變壓料力範圍，

參考文獻

[1] European Aluminum Association, (https://www.european-aluminium.eu)

[2] European Aluminum Association, “Aluminium Cars –Unlockin the Light –Weighting Potential”

[3] Ducker Worldwide, LLC. (www.ducker.com)

[4] Drive Aluminum,( http://www.drivealuminum.org/aluminum-101/driving-aluminum/)

[5] European Aluminum Association, (https:// www.european-aluminum.eu/resource-hub)

[6] European Aluminum Association, “The Aluminum Automotive Manual Applications - Car body - Body structures”.

[7] AUDI AG, (www.audi.com/en.html)

[8] P. Appendino, C. Badini, F. Marino, A. Tomasi, “6061 Aluminum alloy-SiC particulate composite: a comparison between aging behaviour in T4 and T6 treatments”, Materials Science and Engineering, A135, pp. 275-279, 1991.

[9] P. Appendino, F. Marino, A. Tomasi, “Natural aging characteristics of aluminum alloy 6061 reinforced with SiC whiskers and particles”, Materials Science arid Engineering, pp. 99-107, 1991.

[10] F. T. Chee, and M. R. Said, “Effect of Hardness Test on Precipitation Hardening Aluminium Alloy 6061-T6”, Journal of Science, pp276-286, 2009

[11] P. Guillon, X. Roizard, P. Belliard, “Experimental methodology to

study tribological aspects of deep drawing-application to aluminum alloy sheets and tool coatings”, Tribology International, 34, pp757-766, 2001.

[12] W. Xu, X. Gao, B. Zhang, L. Yang, “Study on Frictional Behavior of AA 6XXX with Three Lube Conditions in Sheet Metal Forming,” SAE Technical Paper, 2018.

[13] F. Ozturk , E. Esener, S. Toros, C. R. Picu , “Effects of aging parameters on formability of 6061-O alloy”, Materials & Design, 2010 [14] V. K.Barnwal, R. Raghavan, A. Tewari ,K. Narasimhan, S. K.

Mishra, ”Effect of microstructure and texture on forming behaviour of AA-6061 aluminium alloy sheet”, Materials Science & Engineering, pp56-65, 2017

[15] V. K. Barnwal, A. Tewari, K. Narasimhan, and S. K. Mishra, “Effect of plastic anisotropy on forming behavior of AA-6061 aluminum alloy sheet”, Journal of Strain Analysis for Engineering Design, 2016 [16] J. T. Gau, G. L. Kinzel, “A new model for springback prediction in

which the Bauschinger effect is considered”, International Journal of Mechanical Sciences, 43, pp.1813-1832, 2001.

[17] O. O. Jr, “Springback in high strength anisotropic steel”, 6th International LS-DYNA Users Conference Simulation, 2000

[18] T. Uemori, S. Sumikawa, T. Naka, N. Ma and F. Yoshida, “Influence of Bauschinger Effect and Anisotropy on Springback of Aluminum Alloy Sheets”, Materials Transactions, vol. 58, No. 6, pp. 921-926, 2017.

[19] F. Yoshida, T. Uemori and K. Fujiwara, “Elastic-plastic behavior of steel sheet under in-plane cyclic tension-compression at large strain”,

International Journal of Plasticity, Vol. 18, pp. 633–659,2002.

[20] F. Yoshida and T. Uemori, “A model of large-strain cyclic plasticity describing the Bauschinger effect and workhardening stagnation”, International Journal of Plasticity, vol. 18, pp. 661–686, 2002.

[21] 蔡恒光, ”先進高強度鋼板反覆拉壓與雙軸拉伸變形特性之研究”, 國立台灣大學機械工程研究所博士論文, 2012.

[22] F. Barlat, J. Lian,“Plastic behavior and stretchability sheet metals.

PartI ： A yield function for orthotropic sheets under plane stress condition”, International Journal of Plasticity, 5, pp. 51-66, 1989.

[23] D. J. Lege, F. Barlat, J. C. Brem, “Characterization and modeling of the mechanical behavior and formability of A 2008-T4 sheet sample”, International Journal of Mechanical Sciences, 7, pp. 549-563, 1989.

[24] F. Barlat, D. J. Lege, J. C. Brem, “A six-component yield function for anisotropic materials”, International Journal of Plasticity, 7, pp. 693-712, 1991.

[25] F. Barlat, J. C. Brem, J. Liu, “On crystallographic texture gradient and its mechanical consequence in rolled aluminum-lithium sheet”, Scripta Metallurgica et Materialia, 27, pp. 1121-1126, 1992.

[26] H. Laurent, R. Greze, P. Y. Manach, S. Thuillier, “Influence of constitutive model in springback prediction using the split-ring test”, International Journal of Machanical Sciences, 51, pp. 233-245, 2009.

[27] R. Li and K. J. Weinmann, “Formability in Non-Symmetric Aluminium Panel Drawing Using Active Drawbeads”, CIRP Annals - Manufacturing Technology, vol. 48, pp. 209-212, 1999.

Through Post-Stretch Forming”, International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, pp. 495-502, 2004.

[29] 姚順偉, “先進高強度鋼板之沖壓成形回彈改善研究”, 國立台灣 大學機械工程研究所碩士論文, 2017.

[30] Z. Chen, G. Fang, and J. Q. Zhao,” Formability Evaluation of Aluminum Alloy 6061-T6 Sheet at Room and Elevated Temperatures”, Journal of Materials Engineering and Performance, 2017

[31] Material Property Data ,( http://www.matweb.com/)

[32] 林建維, “鋁合金板件沖壓成形之研究”, 國立台灣大學機械工程 研究所碩士論文, 2011.

[33] GOM ATOS Core introduction ,( https://www.gom.com/metrology-systems/atos/atos-core.html)

[34] B. P. Justusson, D. M. Spagnuolo, and J. H. Yu, “Assessing the Applicability of Digital Image Correlation (DIC) Technique in Tensile Testing of Fabric Composites”, Army research laboratory, 2013 [35] W. Muhammad, “Measurement of Plastic Strain Ratio Using Digital

Image Correlation”, Journal of Testing and Evaluation, 2017.

[36] R. Hill, “Constitutive modelling of orthotropic plasticity in sheet metals”, Journal of the Mechanics and Physics of Solids, vol. 38, pp.

405-417, 1990.

[37] F. Barlat, J. C. Brem, J. W. Yoon, K. Chung, R. E. Dick, D. J. Lege, F.

Pourboghrat, S. H. Choi, and E. Chu, “Plane stress yield function for aluminum alloy sheets-part1”, International Journal of Plasticity, vol.

19, pp. 1297-1319, 2003.

[38] J. W. Yoon, F. Barlat, R. E. Dick, K. Chung, and T. J. Kang, “Plane stress yield function for aluminum alloy sheets—part2”, International Journal of Plasticity, vol. 20, pp. 495-522, 2004.

[39] 蘇昱竹, “先進高強度鋼板沖壓成形回彈現象之研究” , 國立台灣 大學機械工程研究所碩士論文,2007.

[40] V. K. Barnwal, R. Raghavan, A. Tewari, K. Narasimhan, S. K. Mishra,

“Effect of microstructure and texture on forming behaviour of AA-6061 aluminium alloy sheet”, Materials Science and Engineering, vol.

679, pp. 56-65, 2017.

[41] S. G. Xu, M. L. Bohn, and K. J. Weinmann, “Drawbeads in sheet metal stamping-A review”, SAE Technical Paper, 1997.

[42] V. Simões, H. Laurent, M. Oliveira, and L. Menezes, “The influence of warm forming in natural aging and springback of Al-Mg-Si alloys”, International Journal of Material Forming, pp. 57–68, 2018

[43] 鄭耀偉, “高溫摩擦試驗設備改良與熱沖壓摩擦特性研究”, 國立 交通大學機械工程學系碩士論文, 2018

[44] J. Hardell, B. Prakash, Kurt Steinhoff, “High Temperature Tribological Studies on Surface Engineered Tool Steel and High,” Metal Forming, pp. 665-670, 2009.

在文檔中 鋁合金板件沖壓成形之回彈分析與改善研究 (頁 152-0)