Browsing by Author "Norrish, J"

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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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    Hardness-tensile property relationships for HAZ in 6061-T651 aluminum
    (American Welding Society, 2014-08) Stathers, PA; Hellier, AK; Harrison, RP; Norrish, J
    High-strength aluminum is used extensively in industry, with welding being a widely used fabrication method. This work focuses on welding of 6061-T651 aluminum and establishment of the hardness–tensile properties relationship in the heat-affected zone (HAZ) of a gas metal arc weld using 4043 filler material. Test welds were prepared from 12.7-mm-thick plate with a single-V weld preparation. Base plate temperatures were measured with an array of eight embedded thermocouples during welding, relating temperature to properties at intervals from the weld. Through-thickness slices 1.7 mm thick were removed, by electric discharge machining, from the plate parallel to the weld at 2-mm intervals and extending from the weld centerline to 40 mm. into the HAZ and base plate. Tensile samples were prepared from these slices, and tensile properties and hardness values measured to establish a relationship between these two parameters. Both EQUOTIP (portable hardness tester) and Vickers microhardness measurements were conducted and related to tensile properties. Although a significant body of work exists relating tensile properties to hardness, no previous study was found that used this approach. Most work appeared to use cross-weld tensile tests, which only give the point of lowest strength. Sections of base plate material having a different thickness (31.75 mm) from that of the welded samples, and from a different source, were thermally aged to four hardness values and the hardness–tensile relationship was also established for this material. These results were compared with those of the HAZ samples; the results were found to fall within the scatter band of HAZ results.