Questions for Study and Discussion 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
What are some of the specific advantages of GMAW? Why is DCEP current used for GMAW? What results can be expected if DCEN current is used? How does a constant-voltage (CV) welding machine differ from a constant-current (CC) welding machine? What is the advantage of using a CV welding machine for GMAW? What are the elements that make up air? Why is oxygen generally a harmful element in welding? Why does nitrogen cause the most serious problems in welding? When is argon or an argon-oxygen mixture considered the ideal gas for shielding? When is CO2 better for shielding than an inert gas? How is it possible to determine the proper gas flow for shielding? What happens if the gas flow is allowed to drift from the weld area? What factors must be taken into consideration in selecting the correct diameter welding wire? How is the welding wire fed to the welding gun? What determines the rate at which the wire feed should be set? Why is the correct electrode extension important?
Refer to Chapter 19 in the Welding Skills Workbook for additional exercises.
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234 Welding Skills