Materials and Processes Flashcards
What does the magnetic particle inspection basic process consist of?
The basic process consists of
1) magnetizing a part
2)applying ferromagnetic particles to the surface to be inspected.
If a discontinuity is present, the particles will form a recognizable pattern on the surface.
What nondestructive testing methods could be used for detecting surface cracks in aluminum fittings?
Dye penetrant, radiography (x-ray), eddy current, ultrasonic testing, and visual inspection.
What occurs during the preparation stages when penetrant inspection liquid is applied to, and then removed, from a part that is cracked?
The penetrating liquid enters the crack and remains there in order to make the crack visible after developer is applied.
What is the procedure for performing penetrant inspection?
1) Clean the surface
2) Apply penetrant
3) Remove the penetrant with emulsifier or cleaner
4) Dry the part
5) Apply developer
6) Inspect and interpret results
How may AN standard steel bolts be identified?
AN bolts can be identified by the code markings on the bolt head
What do the markings on the heads of solid shank rivets indicate?
The material of which they are made and their strength
How can the recommended torque for a bolt or nut be determined when torque values are not called out in the maintenance procedure?
From the information contained in the standard torque table.
What does the grip length of a bolt correspond to?
The thickness of the material being fastened with the bolt.
What may be accomplished to prevent heat treated aluminum alloy rivets from becoming hard after the quenching sequence?
Store the rivets in the refrigerator at a temperature lower than 32 degrees (F). They will remain soft for several days.
Where may self locking nuts NOT be used?
At joints which subject either the nut or bolt to rotation.
What is the difference between a general purpose bolt and a close tolerance bolt?
Close tolerance bolts are machines more accurately than general purpose bolts.
What type of cable is commonly used in primary control systems?
Extra flexible 7x9 stainless steel cable
How is work hardening obtained?
By cold working metal
What width would a welding bead have and what should be the depth of penetration in a butt weld?
The bead width should be 3 to 5 times the thickness of the base metal and 100 percent penetration for a butt weld.
What are the undesirable characteristics of a cold weld?
A cold weld has improper penetration with rough and irregular cold laps not feathered into the base metal
What are the penetration requirements for a fillet weld?
A fillet weld should be 25 to 50 percent of the thickness of the base metal
What precision measuring instruments are used to measure outside dimensions?
Outside micrometer calipers and Vernier calipers
Why should a micrometer be periodically calibrated?
1) Continually sliding objects between the anvil and spindle may wear the surfaces
2) If it is dropped, its accuracy may be affected
3) If the spindle is overtighened, the frame may be permanently sprung (bent)
Why is alloy steel that is responsive to heat treatment usually less suitable for welding?
Because of its tendency to become brittle and lose its ductility in the welded area
What is the main difference between thermoplastic and thermosetting resins(plastics)?
Thermoplastic resins can be softened by heat and become hard again when cooled down. Thermosetting resins do not soften when heated and will char and burn rather than melt.
What are some of the purposes for which thermoplastic and thermosetting resins are commonly used in modern aircraft?
Thermoplastic acrylic (plexiglas) is commonly used for windshields and side windows.
Thermosetting resins are commonly used as the matrix material in composites.
Name one substance commonly used as the matrix material in structural composite laminates.
1) Aramid (Kevlar)
2) Fiberglass
3) Graphite (or carbon) fiber
Name one substance commonly used as the matrix material in structural composite laminates
Polyester resin and Epoxy resin
Name on advantage of using pre-impregnated materials in the construction of repair of composite components (Besides saving time)
1) Prepreg fabric contains the proper amount of matrix
2) The reinforcing fibers are completely and evenly permeated with matrix.
3) The matrix has the correct proportions of resin and hardener.
