Copyright Goodheart-Willcox Co., Inc. Chapter 8 Gas Metal and Flux Cored Arc Welding 239 22. True or False? The travel angle for FCAW–S should be very large in order to ensure good shielding gas coverage. 23. True or False? FCAW is welded vertically downhill. 24. True or False? Gas metal arc spot welding on thin metal can be performed in any position. 25. True or False? Ozone, a toxic gas, is produced during GMAW and FCAW. Apply and Analyze 1. Which gun angle results in the deepest penetration—forehand or backhand? 2. What factors must be considered when choosing a shielding gas? 3. Why is good ventilation important when using CO 2 gas? 4. Why is argon usually mixed with small amounts of oxygen or carbon dioxide when the spray transfer method is used on carbon steel? 5. What argon fl ow rate should be used to weld 1/4″ (6.4 mm) thick carbon steel? 6. Why should gas fl ow rates for CO 2 and argon be increased for out-of-position welding? 7. Explain why downhill FCAW is diffi cult to perform. 8. Why are several narrow beads recommended for overhead welds with FCAW or GMAW? 9. What is the advantage of spot welding with GMAW over resistance spot welding? 10. How can the condition of excessively wide beads be corrected? Critical Thinking 1. Three common weave patterns are described in the text, oval, W- and Z-weave. Think of another weave pattern that you have used or could use. What would be a good application for your weave pattern? 2. Compare GMAW and FCAW–S to another welding process. You pick the other welding process. Are GMAW and FCAW–S processes more or less expensive than the other welding process? Consider equipment cost, material cost, and labor cost. Explain your conclusion. Experiment 1. Weld a root pass on a groove weld in the fl at position using GMAW. Deliberately produce some whiskers. What happens to the arc, the electrode wire, and the keyhole when whiskers are being produced? Where is the electrode located when the whiskers are produced?