Copyright Goodheart-Willcox Co., Inc. 140 Gas Tungsten Arc Welding Handbook 10. Move the torch forward approximately 3/32″ (2.4 mm) and add welding rod again as in Step 8. 11. Continue moving the arc across the joint, adding welding rod as before. A. Maintain the proper torch angles. B. Maintain the proper filler rod angles. 12. Stop the weld at the end of the plate. Remember to hold the torch at the end until the weld cools. Problem Areas and Corrections: 1. Undercut at top of weld crown. Possible cause: Torch angle flat. Solution: Maintain the proper torch angles. Possible cause: Not enough filler metal added to the weld pool. Solution: Add welding rod to the top of the weld pool. 2. Crown sags. Possible cause: Gravity. Solution: Add welding rod to the top of the weld pool. Solution: Do not add welding rod in large amounts. Solution: Move the torch with a slight circular motion to hold pool in position. 3. Penetration is uneven on the centerline of the weld. Possible cause: Torch not centered on the joint. Solution: Keep the electrode centered on the joint. Welding Procedure Number 8-5 Weld joint type: Square-groove butt Position: Vertical uphill Material type: Cold-rolled steel Thickness: 1/16″ (1.6 mm) Filler metal: ER70S-2 or 6 Diameter: .045″–.062″ (1.1 mm – 1.6 mm) Machine setup: DCEN high-frequency start Shielding gas: Argon CFH: 15–25 Tungsten type: 1%, 1.5%, or 2% lanthanated, ceriated, or thoriated Diameter: 1/16″ (1.6 mm) (tapered) Procedure: 1. Prepare and clean the materials. 2. Tack weld the plates together. 3. Align the parts to be welded with the joint in the vertical position. 4. Align the torch to the angles shown in Figure 8-16 and move the torch toward the joint until the tip of the electrode is approximately 1/8″ (3.2 mm) from the surface. 5. Hold the welding rod so the end is approximately 1″ (25.4 mm) from the electrode. 6. Start the arc at low current. Move the torch toward the joint until the tip of the electrode is approximately 1/16″ (1.6 mm) from the surface. 7. Increase the amperage to form a weld pool approximately 3/16″ (4.8 mm) in diameter. 8. Bring the welding rod into the upper part of the pool and melt enough filler metal to form a slight crown on the surface. 9. Draw the welding rod approximately 1/2″ (12.7 mm) away from the weld pool. 10. Move the torch upward approximately 3/32″ (2.4 mm) and add welding rod again as in Step 8. 11. Continue moving upward, adding welding rod as before. 12. Stop the weld at the end of the plate. Remember to hold the torch at the end until the metal cools. Figure 8-16. Torch and welding rod positions for a square-groove butt weld in the vertical position. (Mark Prosser)