多孔穴鋁合金管件擠製之有限元素分析

Finite Element Analysis of Multi-Hole Extrusion of　Aluminum-Alloy Tubes

莊文章(Wen-Chang Chuang)

指導教授 ： 陳復國

國立臺灣大學/工學院/機械工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01387

摘要

鋁合金由於具有密度低、強度強之特點，目前因輕量化方面之應用而成長快速，而無縫管件擠製製程適合量產高強度、焊接不易之鋁合金空心製品，因此本論文利用有限元素模擬探討鋁合金之無縫管件擠製。
首先針對單孔穴無縫管件擠製，初步探討各製程參數對擠壓力及材料溫度的影響，以暸解無縫管件擠製成形的製程特性，接下來本論文利用分析後的單孔穴擠製模型之模具進行實際之實驗驗証，藉由比較模擬結果及實驗所得到之數據，以驗証有限元素軟體DEFORM對無縫管件擠製之適用性。
多孔穴無縫管件擠製應用於高強度合金時，因擠製壓力甚大，且材料流動對心軸而言並非均勻對稱，以致使心軸偏心，經本研究進行初步模擬後，發現材料流動會使初始製程的出口管件發生彎曲偏斜的現象，並且造成心軸兩側的正向壓力有所差異，而再針對可能影響出口材料流動之各項參數進行分析後，可知孔穴數目以及孔穴位置配置之影響甚鉅，並且由模擬可在孔穴作用區域的形心附近找到流動情形較佳的孔穴位置，能讓心軸內外側的受力差異明顯減少。
最後藉由DEFORM軟體之模具受力分析模組，即可看出心軸偏心情形的改善，而本論文所獲得之研究成果可提供鋁合金擠製成形業者進行製程規劃以及模具設計時的參考。

關鍵字

A7075鋁合金 ； 擠壓成形 ； 多孔穴 ； 模具設計 ； 無縫管件 ； 有限元素法

並列摘要

The superior properties of aluminum-alloy attracted attentions from the light-trend industry recently. Although the principal manufacturing process of the aluminum-alloy hollow products has been extruded by using porthole dies, the seamless extrusion with a mandrel has considerable potential because of its competitive productivity and performance. So the seamless extrusion process of aluminum-alloy tubes at elevated temperatures was studied in the present study by the finite element analysis and experiments.
The trend of processing load and temperature on single-hole die extrusion was studied at first, the finite element software DEFORM was employed to simulate the hollow tubes processes. The experiment of single-hole die extrusion was practiced to verify the analyzed results. The experimental results obtained in the present study show good agreement with simulations. It shows the finite element software DEFORM is suitable to process of seamless tube extrusion.
In order to increase the productivity, multi-hole die with several mandrels is applied. But the defects, which are the bias of mandrel and the unbalanced thickness of production caused by material flow are critical issues. The influence of important process parameters such as the temperature, extrusion speed, production dimension, billet size, number and position of holes on die are analyzed by simulations. According to the results of analysis, it shows the serious effect could be caused by the number and position of holes on die. Besides, the material flow is better when the hole is near the focus of action area. The bias phenomenon of mandrel could be improved after die stress analysis by the software DEFORM. The results of this study can be reference resources for related academic research and can also be used to develop related products for industry production.

並列關鍵字

A7075 aluminum-alloy ； Extrusion ； Die design ； Seamless tube ； Finite element method

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