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采用手工交流钨极氩弧焊、ER5356焊丝和2A12铝合金板材制备了焊接接头疲劳试样,进行了弯曲疲劳试验,并通过扫描电镜、金相显微镜等显微分析方法对焊接接头试样的疲劳断裂特征和焊接缺陷进行了综合分析。结果表明,因焊接规范不当、操作技术不熟、温度掌握不准等原因,铝合金手工钨极氩弧焊容易产生微裂纹、气孔、夹渣和未熔合等焊接缺陷,这些焊接缺陷的存在增加了焊接接头疲劳裂纹萌生和扩展速度,从而降低了焊接接头的抗疲劳断裂性能。最后分析了控制焊接缺陷产生的方法。
Tensile specimens of welded joints were prepared by manual exchange TIG welding, ER5356 welding wire and 2A12 aluminum alloy plates. The bending fatigue tests were carried out. The fatigue of the welded joint samples was analyzed by microscopic analysis methods such as scanning electron microscopy and metallographic microscope Fracture characteristics and welding defects were analyzed. The results show that due to improper welding specifications, unfamiliar operating techniques and inaccurate temperature control, the welding defects such as micro-cracks, pores, slag inclusions and unmelting easily occur in the aluminum alloy GTAW. The existence of these welding defects is increased The fatigue crack initiation and propagation speed of welded joints, thus reducing the fatigue fracture resistance of welded joints. Finally, the method of controlling the welding defects is analyzed.