Copyright Goodheart-Willcox Co., Inc. Chapter 8 Manual Welding Techniques 137 5. Increase the amperage and form a weld pool approximately 3/16″ (4.8 mm) in diameter. 6. Move the torch forward while: A. Maintaining the weld pool size B. Maintaining the torch height C. Maintaining the torch angles 7. Stop the weld at the end of the plate. A. Do not lift the torch away from the plate. Postflow gas will protect the hot metal during the cooling period. Problem Areas and Corrections 1. Uneven top weld width and depression. Possible cause: Variation in welding speed. Solution: Maintain a consistent travel speed. Possible cause: Heat buildup in the weld pool. Solution: Maintain travel speed to reduce heat. 2. Uneven contour. Possible cause: Incorrect torch angle. Solution: Align the torch vertically over the weld. 3. Uneven penetration or lack of penetration. Possible cause: Insufficient amperage. Solution: Increase amperage. Possible cause: Variable torch height. Solution: Keep the torch the same height above the weld pool. Possible cause: Variable travel speed. Solution: Maintain a travel speed that keeps the weld pool a consistent size. Welding Procedure Number 8-2 Weld joint type: Bead on plate Position: Flat Material type: Cold-rolled steel Thickness: 1/16″ (1.6 mm) Filler metal: ER70S-2 or 6 Diameter: .045″ (1.1 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. Raise the part to be welded 1/8″ (3.2 mm) above the table with metal blocks. 3. Align the torch to the angles shown in Figure 8-13 and lower the torch until the electrode tip is approximately 1/8″ (3.2 mm) from the top surface. Figure 8-12. Torch position for an autogenous weld in the flat position. (Mark Prosser) Figure 8-13. Torch and welding rod positions for running a bead on a plate in the flat position. (Mark Prosser)