Abstract
Inert-gas arc welding of pipe and other weld-root beads supplemented by inert-gas inside shielding has improved greatly the deposited-metal quality and degree of penetration, but requires superlative operator skill to achieve reasonably uniform results. The process which is the subject of this paper through precise control of technique, physical dimension, and internal-shielding gas pressure, provides assurance of complete penetration, uniform root-bead inside surface free of undercutting, and desired degree of root-bead reinforcement, with only average operator proficiency. This process of controlled contour-shielded root welding designated as “K-Weld,” has been applied successfully to 9½ in OD × 1⅝ in. wall Type 347 ausfenitic utility main steam lines, and other difficult applications.
