Through the comparison test of 5059 Al-Mg alloy 4 mm automatic TIG welding, it is concluded that when the heat input is 13.8 kJ/cm, the weld microstructure is a large equiaxed crystal structure with dendritic growth within the crystal, and the average grain size is about 2.56. The second phase contains 7.78%Mg and 9.20%Mn, according to the energy spectrum (EDS) in the weld zone. The tensile strength of the joint is less than 330 MPa. When the heat input is reduced to 12.5 kJ/cm, by adjusting the working state of the welding pressure frame tool, the welding test plate can be effectively pressed and the weld cooling rate can be improved. The weld microstructure is small equiaxed crystal structure, which is arranged in a regular strip, and the average grain size is about 4.91. It was found that the second phase contained 11.10%Mg and 8.86%Mn, and the joint formed a metal compound strengthening phase containing Mg and Mn, dispersed in the aluminum matrix, and the content of Mg and Mn was high. The microhardness of the weld zone could reach more than 90% of the microhardness of the substrate, and the tensile strength of the joint could meet 330 MPa.
Al-Mg alloyTIG weldingheat inputgrain size numberroom temperature tensile property
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