Copyright Goodheart-Willcox Co., Inc. Chapter 8 Manual Welding Techniques 139 6. Start the arc at low current. Lower the torch until the electrode tip is approximately 1/16″ (1.6 mm) from the surface. 7. Increase the amperage and form a weld pool approximately 1/4″ (6.5 mm) in diameter. 8. Bring the rod into the front edge of the pool and melt enough rod to form a slight crown on the surface. 9. Draw the rod approximately 1/2″ (12.7 mm) away from the weld pool. 10. Move the torch forward approximately 3/32″ (2.4 mm) and add rod again as in Step 8. 11. Continue moving the arc across the joint, adding rod as before. A. Maintain the proper torch angles. B. Keep the electrode on the centerline of the joint. 12. Stop the weld at the end of the plate. Be sure to fill the crater completely. Remember to hold the torch at the end until the weld cools. Problem Areas and Corrections: 1. Uneven top weld width and low crown. Possible cause: Variation in travel speed. Solution: Maintain a consistent travel speed. Possible cause: Heat buildup in the weld pool. Solution: Increase the travel speed as the plates get hotter. Possible cause: Variation in adding rod. Solution: Add rod to form a crown. 2. Undercut. Possible cause: Torch not aligned vertically. Solution: Maintain a 90° work angle. Possible cause: Not enough filler metal added to the weld pool. Solution: Add rod to the center of the weld pool. 3. Penetration uneven or lack of penetration. Possible cause: Inconsistent travel speed. Solution: Maintain a consistent travel speed. Possible cause: Inconsistent filler metal application. Solution: Add filler metal to form a crown. Possible cause: Insufficient amperage. Solution: Increase amperage and add more filler metal. Possible cause: Inconsistent torch height. Solution: Maintain a consistent torch height. Possible cause: Improper torch position or angle. Solution: Maintain the proper torch angles and position the torch on the centerline of the joint. Welding Procedure Number 8-4 Weld joint type: Square-groove butt Position: Horizontal 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 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 horizontal position. 4. Align the torch to the angles shown in Figure 8-15 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 as shown in Figure 8-15 and position it 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 rod into the upper part of the weld pool and melt enough rod to form a slight crown. 9. Draw the rod approximately 1/2″ (12.7 mm) away from the pool. Figure 8-15. Torch and welding rod positions for a square- groove butt weld in the horizontal position. (Mark Prosser)