Test Your Knowledge
  1. Name the welding processes covered in this chapter that can use a shielding gas to shield the weld area.
  2. What type of welding current can be used with GTAW?
  3. A GTAW electrode is held in the torch by a(n) _____.
  4. GTAW welding power sources are constant _____ machines.
  5. What is the advantage of using a constant voltage power source?
  6. Why is a high-frequency voltage used continually in an ac circuit that is being used for GTAW?
  7. List five reasons why argon is more frequently used for GTAW than helium.
  8. When GTAW, which shielding gas is best for use in cross drafts? Gives the best cleaning action? Provides the greatest heat conductivity?
  9. A regulator controls and measures _____. A flowmeter measures and controls the _____ of gas flow.
  10. The maximum amperage used on a gas-cooled GTAW torch is generally _____ amperes.
  11. What determines the nozzle diameter that should be used for GTAW or GMAW?
  12. What is the advantage of using thoriated tungsten electrodes?
  13. The color coding of a 2% thoriated tungsten electrode is _____.
  14. The arc welding power source used for GMAW and FCAW produces a constant _____.
  15. GMAW power sources have a sloping voltage curve. How much slope should the curve have for use with carbon dioxide (CO2) gas?
  16. Increasing the wire feed rate in GMAW or FCAW increases the _____ in the circuit.
  17. The shielding gas mixture suggested in Figure 7-41 for welding low-alloy steel with the short circuit GMAW process is _____% –_____% He, _____% –_____% Ar, and_____% –_____% CO2.
  18. Which gas produces the deepest penetration when used in GMAW?
  19. To produce better metal transfer through the arc, reduce spatter, and stabilize the arc, _____ and _____ are added to argon or helium.
  20. Describe the following GMAW electrode completely: ER90S-B3L.
  21. What two methods can be used in FCAW to shield the weld from atmospheric contamination?
  22. When feeding a FCAW electrode through the wire feed mechanism, care must be taken not to _____ the flux cored wire.
  23. Describe five functions that flux can perform during flux cored arc welding.
  24. Describe the following FCAW electrode completely: E80T-2.
  25. What number filter lens is recommended for welding steel with the GTAW process and current of 80A? For welding steel using the GMAW process and a current of 220A?