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2021 №02 (03) DOI of Article
10.37434/tpwj2021.02.04
2021 №02 (05)

The Paton Welding Journal 2021 #02
TPWJ, 2021, #2, 18-26 pages

Influence of heat treatment on the properties of welded joints of V1341 alloy under modeled operating conditions

Authors
L.I. Nyrkova, Т.M. Labur, S.O. Osadchuk, М.R. Yavorska and V.A. Koval
E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua

Abstract
The paper presents the results of comparative studies of corrosion-mechanical resistance of welded joints of V1341 alloy 1.2 mm thick, produced by manual argon-arc welding with free and constricted arc, after different types of heat treatment (HT) — artificial aging and complete cycle heat treatment (hardening and artificial aging). It was shown that artificial aging increases the strength characteristics of welded joints: those produced by free arc — by ~23 %, compared to the base metal, by constricted arc — by ~29 %, but reduces the relative elongation by ~82 % and ~84 %, and the strength coefficient — to 0.77 and 0.71 (0.81 and 0.83 in as-welded state), respectively. The complete cycle of HT provides increase in both strength and ductility. After artificial aging, as well as after a complete heat treatment cycle, the potential difference between the base metal and the HAZ does not exceed the permissible value of 0.05 V (according to GOST 9.005), which will not be dangerous at operation in nonaggressive environments. Artificial aging and full HT cycle do not impair the resistance of welded joints of V1341T alloy to exfoliating corrosion compared to as-welded state, which is assessed as value 2. An increase of resistance to intercrystalline corrosion (ICC) after artificial aging was demonstrated, the maximum depth of which was 0.301 mm for a joint produced by a free arc, and 0.233 mm — for a joint produced by a constricted arc (in as-welded state it was 0.350 mm and 0.47 mm, respectively). After a complete HT cycle, the ICC depth was 0.287 mm and 0.345 mm, respectively. Artificial aging reduces the corrosion-mechanical resistance of welded joints produced by free and constricted arc: the time-to-fracture of the samples was 9 and 12 days, respectively (compared to 45 days in as-welded state), but after a cycle of HT maximum time-to-fracture of welded joints increased to 54 and 31 days, respectively. Welded joints produced by a constricted arc had higher corrosion-mechanical resistance after a complete heat treatment cycle. 14 Ref., 5 Tables, 7 Figures.
Keywords: aluminium alloy, welded joints produced by free and constricted arc welding, mechanical properties, structure, intercrystalline corrosion, exfoliating corrosion, corrosion under constant strain, potentiometry, voltamperometry

Received 18.01.2021

References

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