- - AGRICULTURE CORE CURRICULUM - - (CLF2000) Advanced Core Cluster: AGRICULTURAL MECHANICS (CLF2250) Unit Title: OXYACETYLENE WELDING ___________________________________________________________________________ (CLF2299) Topic: OXYACETYLENE WELDING Time Year(s) UNIT EXAM 1 hour 1 / 2 / 3 / 4 ___________________________________________________________________________ TOPIC PRESENTATION: OXYACETYLENE WELDING NAME ____________________________________ DATE ____________________________________ PER. ____________________________________ A. True or False 1. _____ A pop will always be heard if the torch acetylene is turned off first when shutting down the torch. 2. _____ Acetylene outlets have right-handed threads. 3. _____ Acetylene is very soluble in acetone. 4. _____ Gas regulators increase low cylinder pressures to high hose pressures. 5. _____ The pressure adjusting screw on a gas regulator should be turned counterclockwise (out) to decrease the pressure. 6. _____ New gas hoses are stored with talcum powder inside, which should be blown out before connecting them to the torch. 7. _____ Keep gloves and protective clothing free of oil and grease to avoid combustion if oxygen comes into contact with them. 8. _____ Fumes from cutting or welding galvanized metal are toxic. 9. _____ Cylinders may be lifted by their valves if care is taken not to drop them. 10. _____ The oxygen tank may be used as a pressure supply to inflate tires or blow off surfaces as long as acetylene is not mixed with the oxygen from the tank. 11. _____ Use soapy water from a soap that does not contain oil to find gas leaks. 12. _____ Never weld or cut on concrete because overheated concrete may crack and explode. 13. _____ In an oxidizing flame, the inner cone will be shorter and the flame will be more noisy than the neutral flame. 14. _____ The neutral flame is the flame of choice for oxyacetylene cutting. 15. _____ A bead may be run without a filler rod. 16. _____ Annealing is the process used to soften steel by heating it to a glowing dark-red color and then quenching it when the desired oxide color on the polished surface is obtained. 17. _____ Brazing uses the same welding apparatus as oxyacetylene welding. 18. _____ Bronze filler rods usually have a higher melting point than the metal being bonded. 19. _____ Flame hardening is a process whereby mild steel is heated to a cherry red glow and then allowed to cool slowly. 20. _____ Tempering is the process used to reduce the hardness and brittleness of steel and to relieve internal stresses. B. Matching 1. _____ Joining metal pieces by melting them a. Work Angle together. 2. _____ The filler rod precedes the torch in b. Oxidation the direction of weld. 3. _____ The torch tip precedes the filler rod c. Backfire in the direction of the weld. 4. _____ The angle of the torch or filler rod d. Flashback perpendicular to the direction of the welding bead. 5. _____ The angle of the torch or filler rod e. Fusion Welding parallel to the direction of welding bead. 6. _____ The momentary burning back of the f. Backhand Welding flame into the tip ending in a loud pop (explosion at the tip). 7. _____ An explosion occurring at the tip g. Forehand Welding accompanied by gases burning back into the hoses and regulator (shrill squealing or hissing). 8. _____ The bonding of two metal objects by h. Lead Angle adhesion with a minimum of alloy. 9. _____ The combining of oxygen with any other i. Oxyacetylene substance. Cutting 10. _____ The rapid oxidation or burning of metal j. Brazing at high temperature C. Multiple Choice 1. _____ Which is NOT a true description of oxygen? a. Oxygen is a colorless gas. b. Oxygen has no smell or taste. c. Oxygen is flammable. d. Oxygen readily supports combustion. 2. _____ Which is NOT a true description of acetylene? a. Acetylene is a colorless gas. b. Acetylene has no smell. c. Acetylene is flammable. d. Acetylene is explosive when compressed above 15 psi. 3. _____ Which of the following statements about oxyacetylene cutting applications is NOT true? a. It can be applied to all carbon steels up to 0.25% carbon. b. It can also be applied to higher carbon steels, but only with some difficulty. c. It can be applied to copper, aluminum, or high-nickel alloys. 4. _____ Which range does an oxygen cylinder gauge read? a. 0-30 psi b. 0-200 psi c. 0-400 psi d. 0-4000 psi 5. _____ Which range does an acetylene working gauge read? a. 0-30 psi b. 0-200 psi c. 0-400 psi d. 0-4000 psi 6. _____ Which range does an oxygen working gauge read? a. 0-30 psi b. 0-200 psi c. 0-400 psi d. 0-4000 psi 7. _____ Which range does an acetylene cylinder gauge read? a. 0-30 psi b. 0-200 psi c. 0-400 psi d. 0-4000 psi 8. _____ Which oxide color on reheated polished steel is the hottest? a. Brown b. Blue c. Straw d. Purple e. Yellow 9. _____ Which color emitted from heated metal would indicate the hottest temperature? a. Cherry Red b. Dark Red c. Black Red d. White e. Yellow 10. _____ Which is the best description of a carbonizing flame? a. Excess amount of oxygen. b. Excess amount of acetylene. c. Equal amounts of oxygen and acetylene. Test Key: A. True or False B. Matching 1. T 1. E 2. F 2. G 3. T 3. F 4. F 4. A 5. T 5. H 6. T 6. C 7. T 7. D 8. T 8. J 9. F 9. B 10. F 10. I 11. T C. Multiple Choice 12. T 1. C 13. T 2. B 14. F 3. C 15. T 4. D 16. F 5. A 17. T 6. B 18. F 7. C 19. F 8. B 20. T 9. D 10. B 7/1/91 OLR/tf #%&C