不同气氛对2219铝合金TIG焊接头组织和性能的影响

Effect of Different Shielding Gases on the Microstructure and Properties of 2219 Aluminum Alloy TIG Welding Joint

氩弧TIG焊熔深浅、焊接效率低,难以适用于厚板2219铝合金的焊接。针对此问题,分别采用两面四层氩弧TIG焊工艺和氦弧TIG焊打底两面三层焊接工艺进行焊接,分析了不同工艺对接头组织和力学性能的影响。结果表明:氦弧打底的两面三层焊接接头与两面四层氩弧焊接头相比,由于打底层单次热输入量较大,焊缝过时效区硬度大幅下降,焊缝区等轴晶长大、θ相增多,因此虽然硬度、抗拉强度增大,但是延伸率明显降低。合适的焊接速度和电流可以细化接头处的晶粒,抑制第二相的析出和聚集,从而提高接头的力学性能。

In the paper,as the object,15 mm thick 2219 Aluminum alloy are welded by TIG with helium and argon protecting respectively,and the effect of different processes on the structure and performance of the joints are analyzed.The results show that:compared with joints welded with argon protected,the joints welded with helium protected have a larger hardness in the over-aging zone,due to the larger single-time heat input in the bottom layer.Theαgrains in the weld area grow,and theθ-phase increase,which increases the hardness and tensile strength of the joint,but the elongation decreases significantly.Appropriate welding speed and current can refine the crystal grains and inhibit the precipitation of the second term at the joint,thereby improving the mechanical properties of the joint.