74 GMAW/FCAW Handbook Copyright Goodheart-Willcox Co., Inc. • Weave bead pattern. The weave bead pattern is also called a wash bead pattern or an oscillation bead pattern. The term oscillation refers to side- to-side movement. The weld is wider than a stringer bead and requires a dwell (wait) of the gun at the end of each weave to fill the metal fi into the weld without undercut. See Figure 7-13. Weld Schedules The welding of component parts requires a combination of many parameters and variables. See Figure 7-14. To document all the materials, wire sizes, types of gases, and techniques used to make a weld, these items are listed on a form called a weld schedule, Figure 7-15. Butt Joint Goodheart-Willcox Publisher Figure 7-12. Stringer bead patterns. The bead on the left is called a backstep or zigzag technique and requires a dwell point on each swing backward. Dwell points are marked with dots. The circular bead technique on the right does not have any dwell points. V-Groove Joint Goodheart-Willcox Publisher Figure 7-13. Weave bead patterns. The weave bead pattern is prone to undercut at the outer edges of the weld and requires a hold or dwell point as indicated by the dots. GMAW Welding Variables Welding Variables to Change Penetration Deposition Rate Bead Size Bead Width Increase Decrease Increase Decrease Increase Decrease Increase Decrease Wire Feed Speed— Amperage ↑ ↓ ↑ ↓ ↑ ↓ No effect No effect Voltage Little effect Little effect No effect No effect No effect No effect ↑ ↓ Travel Speed Little effect Little effect No effect No effect ↓ ↑ ↑ ↓ Wire Stickout ↓ ↑ ↑ ↓ ↑ ↓ ↓ ↑ Wire Size ↓ ↑ ↓ ↑ No effect No effect No effect No effect Gas % of CO2 ↑ ↓ No effect No effect No effect No effect ↑ ↓ Torch Angle Backhand Forehand No effect No effect No effect No effect Backhand Forehand ↑ Increase ↓ Decrease Goodheart-Willcox Publisher Figure 7-14. Adjusting welding parameters and techniques affects the weld.