Chapter 12 Knowledge Check

Chapter 12

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

Review Questions

1. The combustion of acetylene and oxygen is the * third * hottest chemical flame burning at about                      .
2. What is the kindling temperature of Acetylene and Oxygen?
   1. 400 °F
   2. 800 °F
   3. 1400 °F
   4. 2000 °F
3. True or False: Can oxy fuel cutting be mechanized?
4. True or False: Fuel hoses are green.
5. What is the maximum pressure that the acetylene regulator should be set to when using acetylene?
   1. 5 psi
   2. 10 psi
   3. 15 psi
   4. 25 psi
6. True or False: Does the regulator show 15 psi as the setting for acetylene?
7. What is soot?
   1. A foot with a sock on it.
   2. Black residue left behind from acetylene that hasn’t completely burned.
   3. Green residue left behind from acetylene that hasn’t completely burned.
   4. Black residue left behind from oxygen not burning completely.
8. What is the first thing you should do when preparing to cut materials with oxy fuel such as oxy-acetylene?
   1. Prestage the oxygen and fuel bottle with the regulator installed for work that will occur the next day on the jobsite.
   2. Wheel in the portable cutting gas bottles, regulator, hoses, and torch to start cutting.
   3. Time is money! And it’s almost the weekend, so the quicker we set up the quicker we go home.
   4. Check your environment for hazards and flammable materials ensuring you have at least 10 feet between cutting operations and your gas cylinders.
9. True or False: Damaged equipment should be replaced.
10. True or False: Oxy fuel cutting is not something that welders need to know how to do.

Answer Key

1. 6000 °F. Other gases like propylene and oxygen can be used for oxy-fuel welding but it burns at a lower temperature, which can make cutting more difficult.
2. 1400 °F.  1400 °F is the kindling temperature which is the temperature at which the fuel gas mixture starts to burn.
3. True. Your school may even have automatic torch machines to aid in beveling pipes and plates. Larger CNC machines consist of tables where materials are placed for cutting, and a computer program is run with the coordinates (path) that the torch will take to make precise cuts.
4. False. The fuel hoses are red while the oxygen hoses are green.
5. 15 psi.15 psi is the maximum pressure the regulator should be set to when using Acetylene gas from a compressed bottle.  This ensures that you are well below the 29.6 psi where acetylene can become shock sensitive and explosive.
6. True. The regulator shows 15 psig above the red background with Acetylene in white letters, and it also shows it on the lower gauge where the background is orange before changing to red above 15 psi in a range marked “Too High.”
7. Black residue left behind from acetylene that hasn’t completely burned.Soot is made of carbon which is black. Soot is not good in areas where stainless steel is used because it can reduce the ability of stainless steel to resist corrosion.
8. Check your environment for hazards and flammable materials ensuring you have at least 10 feet between cutting operations and your gas cylinders. Safety is number one when using compressed gases that can kill or seriously injure you if the work environment caused an explosion or fire.
9. True. Oxy-fuel system should be checked before and after each use. Replace damaged equipment.
10. False. Cutting and preparing material is important to every welder as seen in this Chapter.