The Paton Welding Journal, 2021, №09



2021 №09 (02)

DOI of Article 10.37434/tpwj2021.09.03

2021 №09 (04)

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The Paton Welding Journal, 2021, #9, 15-19 pages

Some advantages of welded joints of aluminium 1201 alloy produced by friction stir welding

A.G. Poklyatskyi, S.I. Motrunich, I.M. Klochkov and T.M. Labur

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 analyzes the structural features, characteristics of strength and resistance to initiation and propagation of in-service cracks of butt joints on 1201 aluminium alloy of 2 mm thickness, produced by friction stir welding (FSW) and argon-arc welding with nonconsumable electrode (argon TIG). It is shown that in FSW as a result of intensive plastic deformation of metal in the weld nugget, a fine-grained structure with a grain size of 5–6 μm is formed. In the zone of thermomechanical impact, deformed extended grains are observed, oriented in the direction of movement of plasticized metal, as well as small equiaxial grains, the size of which varies within 4–12 μm, whereas at argon TIG welding of this alloy the weld metal has a characteristic cast structure with large (0.20–0.25 mm) dendrites. The absence of beads and reinforcements in the welds produced by FSW, allows avoiding high levels of stress concentration in the places of transition from the weld to base material, which negatively affect the service and life characteristics of welded joints. The peculiarities of formation of permanent joints in the solid phase during FSW also help to reduce the degree of metal softening in the welding zone and increase their ultimate strength, and resistance to initiation and propagation of operational cracks. 15 Ref., 7 Figures.
Keywords: microstructure, hardness, ultimate strength, resistance to initiation and propagation of in-service cracks

Received 08.07.2021

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