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采用Al-Si药芯焊丝,研究了纯Al与镀锌钢板的TIG熔-钎焊工艺,分析了接头的界面结构特征及其性能。研究结果表明,在40～60 A的低焊接电流条件下,即可成功实现纯Al与镀锌钢板的TIG熔-钎焊。当焊接电流为40 A时,只有在焊缝/Fe母材结合界面存在Al-Fe-Si三元金属间化合物,厚度约为2 μm,靠近Al母材的焊缝金属由α-Al树枝晶和网状Al-Si共晶组成。当焊接电流增大时,焊缝/Fe母材结合界面金属间化合物中的Fe含量明显增加,可能发生了由Al_9Fe_2Si_2向Al_8Fe_2Si的转变,厚度增至约5 μm,Fe母材表面铺展边沿的焊缝金属中也出现大量长条状金属间化合物,而焊缝金属中心位置至Al母材之间区域没有金属问化合物。Al/Fe接头的抗拉强度系数接近80%,接头断裂发生在Al母材热影响区位置,没有发生在界面金属间化合物层的情况。
The Al-Si flux-cored wire was used to study the TIG fusion-brazing process of pure Al and galvanized steel. The interfacial structural characteristics and properties of the joints were analyzed. The results show that TIG fusion-brazing of pure Al and galvanized steel can be successfully achieved at low welding current of 40-60 A. When the welding current is 40 A, the Al-Fe-Si ternary intermetallic compound is only existed at the weld / Fe matrix bonding interface and the thickness is about 2 μm. The weld metal close to the Al base is composed of α-Al dendrites And reticular Al-Si eutectic composition. When the welding current increases, the content of Fe in intermetallics at the weld / Fe matrix interface increases obviously, and the transformation from Al 9 Fe 2 Si 2 to Al 8 Fe 2 Si may occur, and the thickness increases to about 5 μm. There are also a large number of long strip-like intermetallics in the seam metal, and there is no metallic intermetallic compound in the area between the center of the weld metal and the Al matrix. The tensile strength coefficient of the Al / Fe joint is close to 80%, and the joint fracture occurs in the heat affected zone of the Al base material and does not occur in the interface intermetallic compound layer.