5A06铝合金搅拌摩擦焊热流有限元分析

Finite element analysis of heat flow during friction stir welding of 5A06 aluminum alloy

大厚度铝合金板搅拌摩擦焊工程应用时常用双轴肩焊接工具焊接,而双轴肩焊接工具使用寿命较短、易磨损,铝合金厚板单轴肩搅拌摩擦焊在工程实践中具有重要意义。针对5A06铝合金厚板的单轴肩搅拌摩擦焊过程进行了热流有限元分析,建立了大厚度铝合金板热流仿真模型,分析了5A06铝合金焊接时温度场分布特征、焊接热循环曲线特征,焊接前进侧/后退侧热循环曲线及外加热源、冷源对搅拌摩擦焊温度场的影响。结果表明,单轴肩搅拌焊工具插入工件预热初期,轴肩产热占整个搅拌工具产热70%以上,前进侧和后退侧最高温度相差约40℃,同时施加热源和冷源时能够很好地限制板材底部热量的散失以及轴肩附近温度的快速升高,有利于焊缝质量的提升。

Friction stir welding of thick aluminum alloy plate often adopts the biaxial shoulder welding tool,which has a short service life and is easy to wear.Friction stir welding of aluminum alloy plate with single axial shoulder is of great significance in engineering practice.Taking a 5A06 aluminum alloy thick plate as the research object,we carried out finite element analysis of the heat flow of the single axial shoulder friction stir welding process,established a heat flow simulation model for the thick aluminum alloy plate,analyzed the temperature field distribution characteristics,the thermal cycle curve characteristics,the forward side/back side thermal cycle curves and the influence of extra heat/cold source on the friction stir welding temperature field.The results showed that when the single axial shoulder stir welding tool was inserted into the workpiece for preheating,the heat produced by the shoulder accounted for more than 70%of that of the whole stirring tool,and the highest temperature difference between the forward side and the back side was about 40℃.Adding extra heat source and cold source at the same time could well restrict the heat loss at the bottom of the plate and the rapid temperature rise near the shoulder,which was helpful to the improvement of the weld quality.