Method of welding nickel or nickel alloy products

A pipe welding method that deposits second and subsequent weld beads in welding the circumference of butt-jointed pipes, at least one of the pipes comprising nickel or a nickel alloy, said pipe welding method comprising the steps of:

• generating an arc between the pipes to be welded together and a tungsten electrode held by a welding torch, the pipes serving as a positive pole and the tungsten electrode serving as a negative pole;
• emitting a shielding gas from a confining gas nozzle concentric with the tungsten electrode;
• and
• oscillating a first filler wire integrally with the welding torch in a direction perpendicular to the weld line with a predetermined amplitude and frequency and moving the first filler wire along the weld line while feeding the tip thereof to a part of the molten pool directly below the arc, and oscillating a second filler wire at the same frequency as the first filler wire but 180.degree. out of phase with the oscillation of the first filler wire, and moving the second filler wire along the weld line while feeding the tip thereof into the molten pool.

A pipe welding method that welds the circumference of butt-jointed pipes, at least one of the pipes comprising nickel or a nickel alloy, said pipe welding method comprising the steps of:

• generating an arc between the pipes to be welded together and a tungsten electrode held by a welding torch, the pipes serving as a positive pole and the tungsten electrode serving as a negative pole;
• emitting a shielding gas that comprises an argon-based mixed gas that contains at least one of hydrogen and helium from a confining gas nozzle concentric with the tungsten electrode and thereby confining the apparent flaring angle of the arc to a maximum of 80 degrees;
• and
• applying a first welding pass by moving the welding torch along the weld line while feeding the tip of a first filler wire into a part of the molten pool directly below the arc;
• and
• applying second and subsequent welding passes by confining the arc through said step of emitting the shielding gas, oscillating the first filler wire integrally with the welding torch in a direction perpendicular to the weld line with a predetermined amplitude and frequency and moving the first filler wire along the weld line while feeding the tip thereof to a part of the molten pool directly below the arc, and oscillating a second filler wire at the same frequency as the first filler wire but 180.degree. out of phase with the oscillation of the first filler wire, and moving the second filler wire along the weld line while feeding the tip thereof into the molten pool.