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针对A7N01铝合金MIG焊接工艺,分别采用纯Ar气体和He-N2-Ar混合气体作为保护气体,并通过拉伸、弯曲、硬度以及疲劳试验分析焊接接头的力学性能。试验结果表明:与纯Ar气体保护焊相比,采用He-N2-Ar混合气体焊接时,A7N01焊接接头在循环寿命为107条件下的疲劳强度提高约9.3%,而接头准静态拉伸性能的改善效果有限,其抗拉强度仅提高约2.5%;在He-N2-Ar混合气体保护条件下,焊接接头疲劳性能改善的主要原因是焊缝气孔数量明显减少,而焊接气孔对接头的准静态抗拉强度影响不大。
For the A7N01 aluminum alloy MIG welding process, pure Ar gas and He-N2-Ar mixed gas were used as the protective gas, and the mechanical properties of the welded joints were analyzed by tensile, flexural, hardness and fatigue tests. The experimental results show that the fatigue strength of A7N01 welded joints increases by about 9.3% with the cycle life of 107 compared with pure Ar gas welding, while the quasi-static tensile properties The tensile strength is only increased about 2.5%. Under the condition of He-N2-Ar mixed gas protection, the fatigue property of the welded joint is improved obviously because the number of the stomata of the weld joint is obviously reduced. However, Tensile strength has little effect.