TIG Welding Pipe - Walking the Cup Techniques

Overview

• Walking the Cup: A crucial technique in TIG welding pipe, often a requirement for job interviews in TIG welding.
• Images: Visuals provided to illustrate different walking techniques.

Techniques to Walk the Cup

1. Ratcheting the Cup

   • Similar to using a ratchet on a bolt.
   • Used on flat surfaces to keep arc length close to the puddle.
   • High weld quality, but difficult to master.

2. Wobbling the Cup

   • Side-to-side motion like moving a heavy barrel.
   • Easier than ratcheting, used with larger cups.
   • Less precision due to changing arc length.

3. Sliding the Cup

   • Cup slides to guide tungsten.
   • Used on odd surfaces or in grooves of heavy wall pipes.
   • Combination of sliding and walking depending on surface.

TIG Welding Pipe with an Open Root

• Joint Preparation: Clean and even bevel, mill scale removal.
• Gap Setting: Use TIG wire to maintain uniform gap.

Tacking the Pipe

• Procedure: Place filler wire in groove, tack with TIG torch.
• Techniques: Shake torch slightly, ensure fusion on both bevel sides.
• Feathering Tacks: Smooth out during root pass.
• Contamination: Clean everything, including tungsten.

Pipe Welding Techniques for an Open Root

• Variations: Northern (lay wire, walk over), Southern (feed from inside).
• Technique Depends on Pipe Thickness:
  • Thin wall: Ratchet or wobble.
  • Heavy wall: Slide cup.

Common Problems with Open Root TIG Welds

• Concave Root Surface or Suck Back: Solution involves adjusting speed, amperage, and techniques.

Techniques for Hot Pass and Filler Passes

• Higher Heat Settings: Example, 90 amps for root, 125 amps for hot pass.
• Sliding vs. Walking: Slide on heavy wall, walk on thin.
• Bevel Washing: Ensures filler wire properly fuses.

Cap Welding Techniques

• Ratcheting Preferred: but can wobble.
• Common Issues: Undercut resolved by cleaning weld area.

Key Takeaway: Cleanliness

• Ensuring clean joints, filler wire, and tungsten are essential for quality TIG welds.