Browsing by Author "van Duin, S"

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    Mechanical characterization of advanced welding processes applied to DH36 butt welds
    (Engineers Australia, 2017-01-01) Levieil, B; Paradowska, AM; Bridier, F; Sterjovski, Z; van Duin, S
    The welding processes currently used in the defence shipbuilding industry are a major source of hull distortion, and may often result in costly rework. In the past decade, a number of novel welding techniques have shown the potential to reduce welding induced distortion. In particular, Tandem-Gas Metal Arc Welding (T-GMAW) may influence the distribution of residual stresses introduced by the welding and, thus, the distortion. In this study, T-GMAW and GMAW were used to fabricate 1m long butt weld specimens made of 5mm DH36 steel. A comparison of the measured out-of-plane distortion for both processes is presented in this paper. The use of T-GMAW reduced the peak longitudinal distortion by 25% and the angular distortion by 33%. The residual stresses profiles of the two processes were characterized at ANSTO using the neutron diffraction strain scanning instrument "KOWARI" and have shown very little difference between the processes. Microstructural characterization, impact toughness and hardness testing were also carried out and shown very little difference between the two processes. Furthermore, the use of T-GMAW process allowed to double the welding speed in comparison to GMAW. The use of T-GMAW for naval shipbuilding could thus allow cost savings and shortened manufacturing delays due both to a higher welding speed and a reduced amount of rework.
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    Neutron diffraction residual stress determinations on Intermetallic alloy components produced by wire-arc additive manufacturing (WAAM)
    (Elsevier, 2019-10-01) Shen, C; Reid, M; Liss, KD; Pan, ZX; Ma, Y; Cuiuri, D; van Duin, S; Li, HJ
    The Wire-Arc Additive Manufacturing (WAAM) process is an increasingly attractive method for producing porosity-free metal components. However, the residual stresses and distortions resulting from the WAAM process are major concerns as they not only influence the part tolerance but can also cause premature failure in the final component during service. The current paper presents a method for using neutron diffraction to measure residual stresses in Fe3Al intermetallic wall components that have been in-situ additively fabricated using the WAAM process with different post-production treatments. By using averaging methods during the experimental setup and data processing, more reliable residual stress results are obtained from the acquired neutron diffraction data. In addition, the present study indicates that the normal residual stresses are significant compared to normal butt/fillet welding samples, which is caused by the large temperature gradient in this direction during the additive layer depositions. © 2019 Elsevier B.V.