GAS-METAL-ARC WELDING OF ALUMINIUM AND ITS ALLOYS

众所周知，铝及其合金在使用Ar气氛进行弧焊时，很难获得焊缝金属的无气孔、深熔深和良好的力学性能。对铝及铝镁合金5083进行了Ar-N混合气体保护焊试验，并对其适用性进行了检验。研究结果如下：(1)采用Ar-N混合气体保护，将铝和铝锌合金电极丝焊接在铝板上。研究了保护气体中氮含量和焊丝锌含量对焊缝成形、熔深、气孔、显微组织、硬度和拉伸性能的影响。在氩气保护气体中加入一定量的氮气，焊缝成形良好，熔深深，气孔少。在焊丝中添加锌降低了焊缝金属的气孔率。氮和锌的加入导致了AlN相和锌的…焊缝金属中固溶体较多。维氏硬度随氮锌加入量的增加而增加。焊缝金属的抗拉强度与母材相同或高于母材，但延伸率与母材相同或小于母材，且随氮锌加入量的增加而降低。(2)采用Ar-N混合气体保护，采用Al-Mg合金5183焊条对5083铝镁合金板材进行了焊接。保护气体中氮气含量对钢珠外观的影响。测试了焊缝金属的熔透深度、气孔率、显微组织、硬度和拉伸性能。在氩气保护气体中加入一定量的氮气，焊缝成形良好，熔深深，焊缝金属无气孔。氮的加入在焊缝金属中生成了细小的AlN相。保护气体中氮的加入量超过20%时，焊缝金属的硬度等于或高于母材的硬度。焊缝金属的屈服应力和抗拉强度与母材相近，但延伸率小于母材。较少

It is well known that aluminium and its alloys are very difficult to obtain no porosity, deep penetration and good mechanical properties of the weld metals, when they are arc-welded using an argon atomosphere. An argon-nitorogen mixture gas-metal-arc welding was tried to aluminium and Al-Mg alloy 5083, and the aplicability was examined. The results are as follows.(1) Aluminium plates were welded with aluminium and aluminium-zinc alloy electrode wires using argon-nitrogen gas mixture shielding. The effects of the nitrogen percent in shielding gas and the zinc content of electrode wire on the bead appearance, penetration, porosity, microstructure, hardness and tensile properties of weld metal were examined. Some amount of nitrogen gas addition to the argon shielding gas brought a good bead appearance, deep penetration and less porosity in the weld metal. Zinc addition to the electrode wire decreased the porosity of weld metal. The nitrogen and zinc addition resulted in AlN phase and zinc … More solid solution in the weld metal. The Vickers hardness increased with the nitrogen and zinc addition. The tensile strength of weld metal was equal or higher than those of base metal, but the elongation of weld metal was equal or less than that of base metal and decreased with the nitrogen and zinc addition.(2) Al-Mg alloy 5083 plates were welded with Al-Mg alloy 5183 electrode wire using argon-nitrogen gas mixture shielding. The effects of the nitrogen percent in shielding gas on the bead appearance. penetration depth, porosity, microstructure, hardness and tensile properties of weld metal were examined. Some amount of nitrogen gas addition to the argon shielding gas brought a good bead appearance, deep penetration and no porosity in the weld metal. The nitrogen addition produced fine AlN phase in the weld metal. More than 20% addition of nitrogen into the shielding gas made weld metals having equal or higher hardness than that of the base material. The yield stress and tensile strength of weld metal were close to those base material, but the elongation of weld metal was less than that of base material. Less