The hot wire process heats the filler wire before it enters the weld pool. 4. How many seconds of gas postflow should be selected if the machine is se...
Chapter 8 1. Which dc electrical polarity, DCEN or DCEP, requires a larger electrode diameter? Why?
2. The best direct current polarity to use for cleaning surface oxides off aluminum or magnesium is DCE___.
3. True or False? The hot wire process heats the filler wire before it enters the weld pool.
4. How many seconds of gas postflow should be selected if the machine is set to deliver 130A?
5. When GTAW 1/8" mild steel, what amperage is suggested when welding a lap joint?
6. Which inert shielding gas generally provides the best surface cleaning action?
7. How many cubic feet per hour (cfh) and liters per minute (L/min) of argon are suggested for this weld?
8. When adjusting a flowmeter, what part of the floating ball is aligned with the desired flow rate line on the flowmeter?
9. What is the exit diameter of a number 4 size gas tungsten arc welding nozzle?
10. List two reasons why a small diameter nozzle is often used.
11. What kind of a tungsten electrode has a yellow band painted on it?
12. A ball is formed on the end of a pure tungsten electrode when welding with _______ current.
13. Name three types of GTAW electrodes used with ac.
14. When grinding a point on a tungsten electrode, in what direction should the grinding marks run?
15. As a general rule, how far should the electrode extend beyond the nozzle?
16. Why is it extremely dangerous to enter a space filled with an inert gas without wearing proper breathing equipment?
17. List and describe three ways of starting the GTAW arc.
18. When gas tungsten arc welding, how is the electrode moved as the filler rod is added?
19. When GTAW, the electrode is held at _______-_______ degrees from the base metal and the filler rod is held at _______-_______ degrees for the base metal.
20. List two causes for rapid tungsten electrode consumption (use).
