Avtomaticheskaya Svarka (Automatic Welding), #2, 2020, pp.50-56
Influence of scandium on mechanical properties of welded joints of D16 alloy produced using filler wires of different alloying systems
A.G. Poklyatskii1, V.E. Fedorchuk1, S.I. Motrunich1, Yu.V. Falchenko1, G.P. Kisla2
E.O. Paton Electric Welding Institute of the NAS of Ukraine. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine.
NTTU «Igor Sikorskii KPI». 37 Peremohi Prosp., 03056, Kyiv, Ukraine.
The impact of scandium in filler wires of SvAMg6, Sv1201 and SvAK5 type, as well as arc oscillations, caused by electric current passage through the filler section, on weld structure formation was studied in nonconsumable electrode argon-arc welding of sheet aluminium alloy D16. Curves of metal hardness distribution in the welding zone are shown and strength limits of welded joints and weld metal after natural ageing of the samples are determined. It is shown that use of scandium filler wires, similar to standard batch-produced ones, leads to formation of a fine-grained dendritic structure of weld metal. However, the subdendritic structure does not form even in welding with arc oscillations, because of a low (0.15 – 0.17%) scandium content in welds. Use of scandium-containing filler wires can lower the degree of weld metal softening at lowering of the total content of the main alloying elements in them. Positive impact of scandium additives together with application of arc oscillations on the degree of softening and ultimate strength of weld metal is noticeable at application of filler wire of Al-Si alloying system. However, the maximum level of strength, both of the welded joints and the weld metal, is ensured in nonconsumable electrode argon-arc welding of D16 alloy 2 mm thick using batch-produced filler wires SvAMg6 and SvMg63. 21 Ref., 2 Tabl., 3 Fig.
Keywords: D16 aluminium alloy, nonconsumable electrode argon-arc welding with arc oscillations, scandium, microstructure, hardness, ultimate strength
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