Pulsed tandem gas metal arc welding (PT-GMAW) has the potential to increase productivity and minimize distortion in the fabrication of naval surface ship panels. In this study, the PT-GMAW process was used in pulse-pulse mode to butt joint weld 5-mm DH36,8-mm HSLA65, 9.5-mm 350WT, and 11-mm HSLA65 steel plate with ER70S-6 wire in order to assess its suitability as a replacement for submerged arc welding (SAW) and gas metal arc welding (GMAW) in panel lines of Australian naval shipyards. In the pulse-pulse mode, the wire feed rates for the leading and trailing welding wires are set independently and they alternately transfer metal into a single molten weld pool at deposition rates almost comparable with single-wire SAW. Radiographic inspection and subsequent analyses of the 8-, 9.5-, and 11-mm single-bead butt joint welds unexpectedly showed varying degrees of weld-end solidification cracking, which occurred within ∼30 mm from the run-off tab and was different than weld crater cracking. The percentage of plates with solidification cracking was greater at larger plate thicknesses due mainly to increases in both the weld bead depth:width ratio and joint restraint as plate thickness is increased. Also, relatively low levels of nickel in the weld metal resulted in less severe solidification cracks compared with weld metal with higher levels of nickel. There was no evidence of solidification cracks in the 5-mm welded plates. Potential strategies to overcome weld metal solidification cracking near the run-off tab in the PT-GMAW of steel are presented.
Sterjovski, Z., Bayley, C., Donato, J., Lane, N. & Lang, D. (2014). Weld-end solidification cracking in pulsed-tandem gas metal arc welding of naval steels. Welding Journal, 93 (5), 145-S-152-S.