Browsing by Author "Larkin, N"

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    Development of a DC-LSND welding process for GMAW on DH-36 steel
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2013-11-02) Paradowska, AM; Law, M; Larkin, N; Holder, R; Li, H; Kuzmikova, L; Pan, Z; Norrish, J; Shen, C
    The reduction of weld induced distortion has become an important focus of research for the shipbuilding industry with the continuing trend of using thinner plates in the ship's hull and super structure. This paper investigates the use of an active cooling process known as Dynamically Controlled—Low Stress No Distortion (DC-LSND) Welding on medium thickness (5 to 6 mm) DH-36 steel. Thermal profiles are obtained. Hardness, distortion and residual stress measurements are also achieved. Results show that the application of a localized cryogenic cooling source trailing the welding arc can significantly reduce weld induced distortion and residual stress using the GMAW process. And welds done by DC-LSND process show a hardening and brittle tendency. The effect of forced cooling on the weld microstructure is also observed.
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    Neutron diffraction residual stress measurements of weldments for shipbuilding application
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2012-11-15) Shen, C; Paradowska, AM; Larkin, N; Li, H; Pan, Z; Law, M
    Pulsed tandem gas metal arc welding (PT-GMAW) has been identified as a welding process potentially capable of increasing productivity and minimising distortion in ship-building. For this study, the PT-GMAW process was used in pulse-pulse mode to butt-weld DH36 steel in order to determine its suitability as a replacement for standard gas-metal-arc welding and submerged-arc welding in naval shipbuilding. Weld residual stresses often lead to increased distortion, and reduction of fatigue life. Quantitative 3D nondestructive neutron diffraction measurements are vital to fully understand the complexity of this welding procedure and their influence on the weld integrity. This paper presents preliminary study of mechanical properties and residual stresses of the welds and their influence on the distortion and fatigue performance. Residual stress measurements were conducted by neutron diffraction at the OPAL reactor on the strain scanner KOWARI. The challenges of the project will be discussed and future planes will be presented.
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    Neutron diffraction residual stress measurements of welds made with pulsed tandem gas metal arc welding (PT-GMAW)
    (Cambridge University Press, 2014-11-10) Paradowska, AM; Larkin, N; Li, H; Pan, Z; Shen, C; Law, M
    Pulsed tandem gas metal arc welding (PT-GMAW) is being developed to increase productivity and minimise weld-induced distortion in ship-building. The PT-GMAW process was used in pulse–pulse mode to butt-weld two different strength and thickness steels; the residual stress and hardness profiles of the welds are reported and correlated. © International Centre for Diffraction Data 2014
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    Neutron optics upgrades to the residual stress diffractometer, KOWARI
    (Materials Research Forum LLC, 2016-07-03) Reid, M; Olsen, SR; Luzin, V; New, M; Booth, N; Clowes, D; Nguyen, T; Franceschini, F; Ogrin, A; Pangelis, S; Paradowska, AM; Larkin, N; Pan, Z; Hoye, N; Suzuki, H
    In the last 5 years a number of significant enhancements have been implemented on the neutron beam strain scanner Kowari at the OPAL reactor in Sydney Australia. These changes have resulted in reduced beam time losses when conducting experiments due to sample and stage alignment, and optics and sample changes. There have been 3 projects, starting in 2011 with a new manual slit system design and collision recovery system, in 2013 with a series of radial collimators and finally with the delivery. © The Authors