Fill in the Blanks
1. gas, electric arc, electric resistance
2. 6300, acetylene, oxygen
3. stir welding
4. metal inert gas (MIG) welding
5. DC straight polarity, AC
6. spot, seam
7. argon, argon/helium or argon/nitrogen
8. colorless, odorless, tasteless
9. green, right hand
10. temperature
11. upright, liquid acetone
12. bigger
13. neutral, carburizing, and oxidizing
14. 6300, oxygen
15. backfire, overheating, loose
16. acetylene, oxygen
17. low carbon, low alloy
18. flux
19. silver, oxygen
20. foot pedal, torch mounted
21. longitudinally, radially
22. AC, cleaning action, surface oxides
23. color, silver
24. bead, groove, fillet, and lap joint
25. warping, a buckling
26. inner
27. formed steel patch plate
28. split sleeve
29. nonrepairable, welded
30. larger diameter
2. 6300, acetylene, oxygen
3. stir welding
4. metal inert gas (MIG) welding
5. DC straight polarity, AC
6. spot, seam
7. argon, argon/helium or argon/nitrogen
8. colorless, odorless, tasteless
9. green, right hand
10. temperature
11. upright, liquid acetone
12. bigger
13. neutral, carburizing, and oxidizing
14. 6300, oxygen
15. backfire, overheating, loose
16. acetylene, oxygen
17. low carbon, low alloy
18. flux
19. silver, oxygen
20. foot pedal, torch mounted
21. longitudinally, radially
22. AC, cleaning action, surface oxides
23. color, silver
24. bead, groove, fillet, and lap joint
25. warping, a buckling
26. inner
27. formed steel patch plate
28. split sleeve
29. nonrepairable, welded
30. larger diameter
True or False
1. false. gas, electric arc, and electric resistance welding.
2. false. Most common for material under 3/16
3. true
4. true
5. false. The rod is not consumed during welding
6. true. Plasma arc can cut all electrically conductive metals.
7. false. Never higher than 15 psi.
8. true
9. false. prevents a high pressure flame or fuel mixture being pushed back into either cylinder causing an explosion.
10. true
11. false. The light intensity of arc welding is much higher and different lenses are required.
12. false; welding tips have one hole; cutting tips several holes
13. false. open acetylene valve before the oxygen valve.
14. true; neutral flame at 5,850 °F; carburizing flame at 5,700
15. false; Always turn off the acetylene valve first
16. true
17. false. Maintain a neutral flame for most steels and a slight excess of acetylene for stainless steel
18. true
19. false; magnesium is done with a neutral flame.
20. false; Thoriated and zirconiated electrodes have better electron emission characteristics.
21. true
22. false; DC straight polarity
23. true
24. true
25. false; use welded split sleeve reinforcements.
2. false. Most common for material under 3/16
3. true
4. true
5. false. The rod is not consumed during welding
6. true. Plasma arc can cut all electrically conductive metals.
7. false. Never higher than 15 psi.
8. true
9. false. prevents a high pressure flame or fuel mixture being pushed back into either cylinder causing an explosion.
10. true
11. false. The light intensity of arc welding is much higher and different lenses are required.
12. false; welding tips have one hole; cutting tips several holes
13. false. open acetylene valve before the oxygen valve.
14. true; neutral flame at 5,850 °F; carburizing flame at 5,700
15. false; Always turn off the acetylene valve first
16. true
17. false. Maintain a neutral flame for most steels and a slight excess of acetylene for stainless steel
18. true
19. false; magnesium is done with a neutral flame.
20. false; Thoriated and zirconiated electrodes have better electron emission characteristics.
21. true
22. false; DC straight polarity
23. true
24. true
25. false; use welded split sleeve reinforcements.
Knowledge Application
1. Gas shielded arc welding.
2. If ignited it is extremely hard to extinguish.
3. The weld zone must be shielded with an inert gas.
4. To have the base metal chemically clean without the slightest film of oxide.
5. A neutral flame.
6. Weld a formed steel patch plate over the dented area.
7. Cool the inner sleeve with dry ice or in cold water.
8. By using a larger tip and adjusting the pressures.
9. Gas shielded arc welding.
10. The acetylene, to allow gas in the tip to burn out.
11. Tack welding at intervals along the joint.
12. Turn off the valves and relieve all pressure.
13. They must be re‐heat treated.
14. A low strength weld.
15. metallic arc welding.
16. A gas is used as a shield around the arc to prevent the atmosphere from contaminating the weld.
17. The weld is stronger, more ductile, and more corrosion resistant.
Multiple Choices
1. b
A stream of inert gas such as argon or helium flows out of the torch and envelopes the arc to exclude oxygen from the area and prevent the formation of oxides.
2. c
The filler rod should be of the same composition as the base metal.
3. c
Repair of magnesium by welding is limited by the fact that if it is used as a structural member, it has probably been heat treated. As is true with heat treated aluminum, welding heat treated magnesium does not leave as much strength as the original metal had.
4. c
The oxyacetylene flame for silver soldering should be neutral, but may have a slight excess of acetylene. It must be soft, not harsh.
5. a
It is necessary to use flux in all silver soldering operations because of the necessity for having the base metal chemically clean without the slightest film of oxide to prevent the silver solder from coming into intimate contact with the base metal.
6. c
All welding on an engine mount should be of the highest quality, since vibration tends to accentuate any minor defect. Engine-mount members should preferably be repaired by using a larger diameter replacement tube telescoped over the stub of the original member, using fishmouth and rosette welds.
7. a
A dent at a cluster should be repaired by welding a specially formed steel patch plate over the dented area and surrounding tubes, as shown in the AC43.13-1B.
8. a
Do not weld brazed or soldered parts as the brazing mixture or solder will penetrate the hot steel and weaken it.
9. a
Joints must be mechanically secure before soldering. If a soldered joint is subject to vibration, it can fail.
10. a
Without being tinned, heat cannot readily transfer from the iron to the work.
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