(1. 湖南大學 汽車車身先進設計制造國家重點實驗室，長沙 410082； 2. 湖南大學 機械與運載工程學院，長沙 410082； 3. 寧夏大學 機械工程學院，銀川 750021)
摘 要: 通過建立6063鋁合金多孔分流模擠壓過程的三維有限元模型，研究不同擠壓速度下擠壓力、焊合面溫度、焊合壓力和材料有效應力等參數的演變規(guī)律及其對焊合質量的影響，建立預測鋁合金方管焊合質量的評價模型，并采用膨脹實驗驗證模型的準確性。結果表明：隨著金屬流入分流孔、焊合室和定徑帶，擠壓力逐漸增大并達到峰值，而后緩慢降低；隨著擠壓速度的增大，焊合面溫度、焊合壓力和有效應力逐漸升高，焊合質量系數k值逐漸降低。膨脹結果表明，最大載荷處的位移與k值呈正相關，說明所建立的k值模型具有較高的精度。
關鍵字: 鋁合金；擠壓；多孔分流模；焊合；有限元
（1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China; 2. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China; 3. College of Mechanical Engineering, Ningxia University, Yinchuan 750021, China）
Abstract:The evolution of extrusion pressure, temperature, welding pressure and effective stress of 6063 aluminum alloy were investigated under different extrusion pressures through building up three-dimensional FE simulation during porthole extrusion, and their effect on the quality of the weld seams were evaluated. The evaluation welding quality model was established and its accuracy was verified by expanding tests. FE simulation results reveal that the extrusion pressure increases with the metal flowing into the inlet ports, welding chamber and die bearing. Over the pressure peak, the extrusion pressure decreases continuously. As ram speed increasing, the temperatures, the mean stresses and the effective stresses on the welding plane in the welding chamber increase. k value shows downward trend with the ram speed increasing. Expanding tests confirm that the extrusion at higher ram speed leads to a bad bonding at the longitudinal weld seams, which corresponds to the k value.
Key words: aluminum alloy; extrusion; porthole die; weld; finite element analysis
