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In this study, hydrogen was determined in the ER5183 wires for MIG welding, and the effect of hydrogen in the wires on the tensile strength as well as the fracture behavior of Al–Mg MIG weld were investigated in order to clarify the affecting mechanism by hydrogen, which provided a reasonable range of hydrogen content in ER5183 welding wires. The results showed that, with the increasing hydrogen content, the tensile strength of the corresponding welds decreased accordingly. During the fracture process of the weld, hydrogen played serious roles as follows, accelerating the fracture process, promoting the formation of pores and causing the decohesion of the inclusion and matrix. By the mechanisms mentioned above, hydrogen changed the feature of fracture morphology from dimples to various defects. Considering the high tensile strength as well as the fine microstructure of the welds, the hydrogen content of the ER5183 welding wires should be controlled below 0.18 μg/g. • Determining the hydrogen content in the ER5183 welding wires for MIG welding. • Investigating the effect of hydrogen content on the tensile strength as well as the fracture behavior of Al–Mg MIG weld. • Finding the decohesion phenomenon, crack and porosity in the weld microstructure. • Giving a reasonable range of hydrogen content in ER5183 aluminum welding wire. [ABSTRACT FROM AUTHOR]

This work focused on the influence of hydrogen content on the microstructure and mechanical properties of ER5183 Al-Mg-Mn alloy wires for aluminum alloy welding. The hydrogen content of the ER5183 wires was measured, the macroscopic and microscopic morphologies of fractures were observed as well as the microstructure of the wires, and the tensile strength of the wires was also tested and investigated. The experimental results demonstrated three typical irregular macroscopic fractures of the wires appeared during the drawing process when the hydrogen content exceeded 0.23 μg/g. In the meantime, the aggregated pores were observed in the microstructure of the ϕ5.2 mm wire with the hydrogen content of 0.38 μg/g. Such defects may become the origin of cracks in subsequent processing and tensile tests. Moreover, higher hydrogen content in the ϕ5.2 mm welding wire will bring obvious changes in the fracture surface, which are internal cracks and micropores replacing the original uniform and compact dimples. With the higher hydrogen content, the tensile strength and plastic strain rate of ϕ1.2 mm wires would decrease. At the same time, unstable crack propagation would occur during the process of plastic deformation, leading to fracture. Considering the mechanical properties and microstructure, the hydrogen content of the ER5183 wires should be controlled below 0.23 μg/g. [ABSTRACT FROM AUTHOR]

As a light-weighting structural material, aluminum alloy is being applied in the automobile and high-speed train, the property of which however is affected by the content of hydrogen, and much importance has been attached to the impact property of aluminum alloy. In this study, hydrogen was determined in ER5183 welding wire and afterwards the effect of hydrogen content on the impact property of Al–Mg MIG weld is investigated to clarify the mechanism of hydrogen action which provided a reasonable control range of hydrogen content in aluminum welding wire. The results show that the impact toughness of the weld is decreased with the increasing hydrogen content. In addition, the decohesion of impurities from the matrix and the formation of porosity are also observed in the weld. The morphology of impact fracture appears facet and porosity due to the "hydrogen-enhanced localized plasticity" effect on plasticity. Considering the good impact property as well as the fine microstructure of the weld, hydrogen content of the ER5183 welding wires should be controlled below 0.18 μg/g. • Introducing hydrogen by using ER5183 welding wires into Al–Mg weld. • Studying the effect of hydrogen embrittlement on impact properties of Al–Mg weld. • Investigating the influence of hydrogen on morphology of impact fracture of Al–Mg weld. • Describing the hydrogen-induced dislocation motion and multiplication phenomenon. • Giving a reasonable range of hydrogen content in ER5183 aluminum welding wire. [ABSTRACT FROM AUTHOR]