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20 Cards in this Set
- Front
- Back
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Why is TIG welding preferred over oxyacetylene welding for building and repairing welded steel tube aircraft structure
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The heat is concentrated in the weld and does not cause as much distortion as gas welding
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What are two types of electric resistance welding used in aircraft construction
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Spot welding, inseam welding
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Why is it important that the pressure of the gas in acetylene cylinder be kept low
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becomes unstable when it is kept under pressure of more than about 15 psi
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What determines the amount of heat that is put into a weld by an
oxy-acetylene torch? |
The size of the orifice in the torch tip
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What is the difference in the appearance of an oxidizing flame, a neutral flame, and a reducing flame produced by an oxy-acetylene torch
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1.)oxidizing flame: pointed inner cone & torch makes a hissing noise.
2.) neutral flame: rounded inner cone & no feather around the inner cone. 3.) reducing flame:definite feather around the inner cone |
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What is meant by tack welding
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small welded spots to hold the material together until the final bead is run
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Why must thick plates of metal be preheated before they are welded
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preheating minimizes the stresses
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Why is it important that all traces of the welding flux be removed after a piece of aluminum or magnesium is welded
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Flux is corrosive
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What is the function of the inert gas that is used in TIG and MIG welding
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the inert gas forms a shield to keep oxygen away from the weld puddle so oxides cannot form and weaken the weld
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What is the difference between brazing and welding
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brazing: the base metal is not melted but is covered with a low melting point alloy.
welding: the base metal is melted |
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What is used as the electrode in TIG welding
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A small-diameter tungsten wire
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Is a heat treated steel part normally repairable by welding
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No welding destroys the heat treatment
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What is the function of the flux in brazing and soldering
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Flux: covers the cleaned and heated metal to keep oxygen away from it. Oxides keep the solder or brazing material from adhering to the surface of a metal
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What kind of solder is recommended for soldering electrical wire
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60/40 resin core solder
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What kind of flame should be used when gas welding aluminum
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A soft neutral oxy Hydrogen flame
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What is an acceptable acetylene line pressure to use when welding with an oxy acetylene rig
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About 5 psi
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What kind of flame should be used when gas welding stainless steel
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A slightly carburizing flame
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How much should the bead penetrate the material when welding two pieces of steel with a butt weld
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The joint should have 100% penetration
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What is meant by a soft flame
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when the pressures of the gases are low enough the flame does not make a noise and does not blow the puddle
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What must be done to an aircraft fuel tank before it can be repaired by welding
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The gas fumes must all be purged from the tank by running live steam threw it for at least 30 minutes, by soaking it in hot water, or by filling it was nitrogen or carbon dioxide
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