高强铝合金的激光-MIG复合焊接的实验研究

以20mm厚的高强铝合金2519-T87为研究对象，研究了激光-MIG复合焊接工艺的工艺参数、坡口形貌以及热处理制度对高强铝合金的平板对接接头的抗拉强度的影响。研究表明：采用类似双U型坡口比国外常用的双V型坡口更有利于复合焊的焊接；保护气体对焊接接头的气孔的形成比较敏感，从而影响焊接接头的抗拉强度，复合焊的保护气体一般采用He气中添加少量的Ar；送丝速度通过改变焊接热输入来影响焊缝组织的晶粒大小以及强化元素的烧损量对焊接接头的强度影响较大。焊后对接头进行合适的热处理，可以显著提升接头的抗拉强度。

Laser-MIG Hybrid Welding on High Strength Aluminum Alloy

The 20 mm thickness high strength aluminum alloy 2519-T87 as the study object was used. It has focused on how the parameters of the laser-arc hybrid welding, groove pattern and the system of heat treatment affect the tensile strength of the butt welding joints. Results indicate that double-U-like groove is useful for hybrid welding used in the oversea; the than the double-V groove shielding gas is sensitive to the formation of the porosity, so as to affect the tensile strength, the shielding gas of the hybrid welding is He and a little of Ar. The wire feed rate is correspond to the heat input. With high heat input, the microstructure of the weld will be coarse and the strengthening elements will be burned loss. By suitable heat treatment, the tensile strength of the post-weld will improve a lot.