| 摘要 |
近年來鋼鐵工業逐年蓬勃發展，無縫鋼管的製造技術也日趨成熟，目前最普遍的無縫鋼管製作方法為鋼管的熱擠壓製程，而本研究的主軸在於無縫鋼管熱擠壓製程中的擴孔製程，其原理是將胚料的內徑由小孔擴充為大孔的過程，本文利用有限元素分析軟體進行擴孔製程的研究，在研究的過程中為了取得材料參數，規畫了圓柱壓縮實驗與圓環壓縮實驗，分別取得不鏽鋼304L的應力應變曲線和材料與模具間的介面摩擦係數，而在圓柱壓縮實驗的部分會有端面效應的產生，本文根據文獻的方法校正材料的應力應變曲線，確實得到合理的結果。將實驗取得的資料匯入有限元素分析軟體中，可讓分析的模型更為準確，而模型當中擴孔力的模擬值也和產線的實際數據作比較驗證。在模擬成果方面，首先調整胚料起始溫度和擴孔速度兩項參製程參數分別對擴孔力的影響進行模擬討論，結果顯示胚料起始溫度對於擴孔力影響較為顯著。最後改變擴孔錐的外型設計，分別固定擴孔錐長度和擴孔錐下部直徑，改變擴孔錐的錐度進行模擬討論，發現在擴孔錐外型設計方面影響擴孔力最關鍵的因素是擴孔錐的錐度。
關鍵字：擴孔、端面效應、有限元素分析
The steel industry thrives in recent years, and
seamless steel tube manufacturing technology matures. The most
common method of producing seamless steel tubes is hot extrusion
process. This study targeted at the hole expansion process which
is one of the hot extrusion process of seamless steel tubes. The
principle is that the inner diameter of billet is expanded to a
large hole. The finite element analysis software is employed to
simulate hole expansion process in the thesis. In order to
obtain material parameters, a cylindrical compression test and a
ring compression experiments were planned. The stress-strain
curve of 304L stainless steel can be obtained by the former, and
the friction coefficient of the interface between the mold and
material can be obtained by the later. The end effect occurs in
the cylindrical compression, so the stress-strain curves are
calibrated according to the literature, and the result after
calibration is reasonable. Importing the experimental data into
finite element analysis software allows more accurate analysis
of the model, and the reaming force value of simulation is
verified with the actual data. In the simulation results, first
discuss the relationship of initial billet temperature and
reaming speed between reaming forces. The results showed the
initial billet temperature has more significant effect to the
reaming force. Finally, change the taper of reaming cone. Fixing
the length and the bottom diameter of reaming cone, and then
changing the taper of the reaming cone. According to the
simulation and discussion, in the changing of the reaming cone
shape, the key point of the reaming force is the taper of the
reaming cone.
Key words：hole expansion, end effect, finite element analysis
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