标题：Variation of chemical composition of high strength low alloy steels with different groove sizes in multi-pass conventional and pulsed current gas metal arc weld depositions
摘要：Abstract 25 mm thick micro-alloyed {HSLA} steel plate is welded by multi-pass {GMAW} and P-GMAW processes using conventional V-groove and suitably designed narrow gap with 20 mm (NG-20) and 13 mm (NG-13) groove openings. The variation of weld metal chemistry in the multi pass {GMA} and P-GMA weld depositions are studied by spark emission spectroscopy. It is observed that the narrow groove {GMA} weld joint shows significant variation of weld metal chemistry compared to the conventional V-groove {GMA} weld joint since the dilution of base metal extends from the deposit adjacent to groove wall to weld center through dissolution by fusion and solid state diffusion. Further, it is noticed that a high rate of metal deposition along with high velocity of droplet transfer in P-GMAW process enhances the dilution of weld deposit and accordingly varies the chemical composition in multi-pass P-GMA weld deposit. Lower angle of attack to the groove wall surface along with low heat input in NG-13 weld groove minimizes the effect of dissolution by fusion and solid state diffusion from the deposit adjacent to groove wall to weld center. This results in more uniform properties of NG-13 P-GMA weld in comparison to those of NG-20 and {CG} welds.
关键词：Pulsed current; Narrow gap; Weld metal chemistry
