Chapter 11 Knowledge Check

Chapter 11

Quiz yourself using the following chapter review questions to check how well you can recall the material.

Review Questions

1. A weld made using only the base metal without filler added is an                     weld.
2. What is one of the main uses of the GTAW process in industry?
   1. Automated welding in automobile manufacturing.
   2. Welding of exotic materials like titanium.
   3. Welding thick sections of steel in shipbuilding.
   4. Out of position welding in outdoor construction.
3. True or False: The welding machine used for GTAW must be a constant voltage power source.
4. True or False: Direct current electrode positive (DCEP) results in the heat being concentrated more on the workpiece.
5. What is the benefit of using a water-cooled torch in GTAW?
   1. It allows use of different tungsten electrode alloys.
   2. It allows the use of a constant voltage power source.
   3. It improves the shielding gas flow.
   4. It prevents overheating during heavy-duty welding.
6. Which shielding gas is commonly used for GTAW?
   1. Oxygen
   2. Argon
   3. Carbon dioxide
   4. Hydrogen
7. Hexavalent chromium is a cancer-causing fume produced when welding chromium-containing alloys (mostly .            steel).
8. Which electrode color indicates 99% pure tungsten?
   1. Gold
   2. Blue
   3. Red
   4. Green
9. True or False: ER70S-2 is a classification for carbon steel filler rods used in both GTAW and GMAW.
10. True or False: Stainless steel welds should have a gray color when done correctly.

Answer Key

1. Autogenous. One of the things that makes GTAW different  is its ability to produce autogenous welds.
2. Welding of exotic materials like titanium. GTAW excels in welding of exotic metals.
3. False. GTAW requires a constant current power source.
4. False. DCEP results in concentrating 30% of the heat in the workpiece and 70% of the heat in the electrode.
5. It prevents overheating during heavy-duty welding. Water cooled torches can weld with higher currents without overheating.
6. Argon. Argon is an inert gas that will not react with other elements, and is an excellent choice for a shielding gas.
7. Stainless. When welding stainless steel or other alloys containing chromium, be sure to use respiratory protection rated for welding.
8. Green. Green indicates 99% pure tungsten?
9. True. “E” refers to “electrode” in GMAW, while “R” refers to filler rod in GTAW.
10. False. A gold or straw color indicates the weld was made with proper heat input.