Materials and processes Flashcards
Name some tools that are commonly used to assist in making visual inspection of welds.
Magnifying glass, flashlight, mirror, and possibly a borescope.
What are some of the non-destructive testing methods that may be used on aluminum parts?
Visual, dye penetrant, eddy current, ultrasonic testing and radiography.
What process occurs during the preparation stage of dye penetrant inspection when the penetrating liquid is applied, and then removed from a cracked part?
The penetrant enters the crack by capillary action and remains there until made visible by developer.
Describe the basic steps for conducting a magnetic particle inspection.
Magnetize the part, coat the surface with ferromagnetic particles. If a defect is present the particles align with the defect forming a visible pattern.
The penetration of a fillet weld should be what percentage of thickness of the base metal?
25 to 50 percent
What telltale characteristic are evidence of a cold weld?
Cold weld has rough irregular edges that are not feathered into the base metal and has variations in penetration amount.
A correctly made butt weld will have what bead width and how much penetration?
3 to 5 times the thickness of the base metal and there must be 100% penetration.
Describe the steps involved in a dye penetrant inspection.
Surface is cleaned , and the penetrant is applied and has to sit for a specified time. Penetrant is then removed with a cleaner. Once removed, the part is dried and then developer is applied, results are the inspected.
What inspection method is used for checking a nonferrous metal part for intergranular corrosion?
Eddy current inspection
Why is it important that all parts be thoroughly cleaned before they are inspected by the dye penetrant method?
Any grease or dirt in a fault will keep the penetrant from seeping into the fault
Why is it important to magnetize a part both circularly and longitudinally when inspecting a steel part by the magnetic practical method?
To detect faults that extend across as well as lengthwise within the part.
Why is a piece of steel tempered after it has been hardened?
When steel is hardened it becomes brittle tempering removes some of this brittleness.
Describe the methods of solution heat treatment of an aluminum alloy.
It is placed in a Furnace to a predetermined temperature, and immediately quenched in water. It is soft when it is removed but as it ages it regains it’s hardness
What are two methods of case hardening?
Carburizing and nitriding
What is indicated by the markings on the head of a solid chalk rivets ?
The material they are made of, and their strength
What is the grip length of a bolt?
The length of the unthreaded portion
How can you keep heat treated aluminum alloy rivets soft enough to install after the quenching process?
Keep the rivets in the freezer they will stay soft for a couple of days
In what way are AN standard steel bolts identified?
By the code markings on the bolt head
What is the most commonly used type of aircraft primary control cable?
Extra flexible 7 x 19 cable
For what type of applications are self-locking nuts not allowed?
Can not be used when either the bold or nut is subject to rotation
How do you work harden a piece of metal?
By cold working the metal
Describe the primary difference between a thermosetting and a thermoplastic resin.
Thermosetting resin doesn’t soften when heated and chars or burns rather then melt.
Thermoplastic resins become soft and pliable when heated and harden when cooled
Explain how thermoplastic and thermosetting resins are commonly used in modern aircraft
Thermosetting resins are used as a matrix material in composite structures. Plexiglas is a thermoplastic resin commonly used as windshields and windows
Name one of the types of resins commonly used as a matrix material for aircraft composite laminates.
Epoxy resin
What are some of the materials that are commonly used as a reinforcing component in a composite structure?
Fiberglass, Kevlar, Carbon fiber, linen and paper
What are the reason that alloy steel is responsive to heat treatment is usually less suitable for welding ?
It may become brittle and lose its ductility in the area of the weld
Give one advantage of pre- preg materials other than saving time in the construction or repair of composite components.
Pre-preg fabrics contain the correct amount of matrix
What type of precision measuring instrument can be used to measure the outside dimensions of aircraft parts?
Outside micrometers and vernier calipers
What should be used to make a visual inspection of a weld?
A magnifying glass of at least power of 10
What system is used to identify AN type bolts
They have markings on the top of the bolt head and bolt diameter is measured in 16ths of an inch and length is 8th of an inch
What is a suitable non destructive method for detecting cracks in aluminum castings and forgings
Dye penetrant inspection
How can the correct grip length be determined
It should be equal to the thickness of the materials to be joined
