Research on the weld performance of 5A03 aluminum alloy with variable gas TIG welding

In the traditional TIG welding process of 5A03 aluminum alloy, the weld is prone to have the problems of low strength and coarse grains. In order to improve the performance of the 5A03 aluminum alloy weld, on the basis of the traditional TIG welding method, by changing the shielding gas supply Method of butt welding experiment on 5A03 aluminum alloy plate with plate thickness of 2.5 mm. After welding, the welds were subjected to tensile test, fracture morphology analysis, observation with polarized light electron microscope and scanning electron microscope, and electrochemical analysis. The results showed that: compared with the welds obtained by traditional welding, the results obtained by 1 Hz variable gas TIG welding The tensile strength of the weld is increased by 18.5 MPa, and the strength is about 10% of that of the traditional weld. The fracture modes of the two welds are plastic fracture. Comparing the weld grain size, it is found that the weld grains obtained under the 1 Hz variable air supply condition are smaller, and the β-phase Al₈Mg₅ presents a dispersed morphology distribution on the aluminum substrate; the electrochemical results analysis shows that the self-corrosion current density of the variable air TIG weld Increased, the capacitive arc radius decreases, and the self-corrosion potential moves to the negative half axis by 0.04 V. The corrosion resistance of the traditional welding seam is better.