厚板双轴肩搅拌摩擦焊温度场及流场数值模拟

Numerical simulation of temperature and flow for bobbin tool friction stir welding of thick plates

针对30 mm厚5A06铝合金双轴肩搅拌摩擦焊的焊接过程,建立温度场及流场的数值模型,计算两种搅拌工具作用下的温度场及流场分布情况。模拟结果发现,双轴肩搅拌摩擦焊接过程中,双轴肩搅拌摩擦焊温度场靠近轴肩区域的温度高,沿板厚中心方向温度逐渐降低,呈哑铃状分布,后退侧温度高于前进侧温度;采用锥形搅拌针焊接时的焊缝温度高于圆柱形搅拌针作用的焊缝。流动场模拟结果表明,工件上、下表面轴肩作用范围内的材料流动最为剧烈,工件内部材料流动相对较弱,采用平行槽结构的搅拌针材料呈横向流动规律,而螺纹结构的搅拌针作用下材料流动较紊乱,材料流动情况与两种搅拌工具作用下的焊缝形貌吻合较好。

The numerical model was established to simulate the 30 mm-thick bobbin tool friction stir welding process, which calculated the temperature field and flow field of two different bobbin tools. It is implied that the high temperature area is near the shoulder, which reduced along the depth to the central plane of the thick plates. The temperature in retreating side is higher than the advancing side. Using the cone-shape probe caused higher temperature than cylinder-shaped tool. It is indicated that material near the FSW shoulder flows more fiercely than inside zone. It flows more turbulently using the screw thread structure than the parallel-grooves probe, which is coincide with the weld shape results.