Materials and Processes Oral Flashcards
What does the code “1100” tell us about aluminum?
99.00 Pure Aluminum
If given an unknown piece of metal, how can you tell if it is titanium or stainless steel?
Two methods can be used: A spark test will give off a brilliant white trace ending in a brilliant white burst. Or moistening the Titanium and using it to draw a line on a piece of glass that leaves a dark line similar in appearance to a pencil mark.
Explain case hardening
It is a heat treating method where the surface of the metal is changed chemically by introducing a high carbide or nitride content producing a hard wear-resistant surface or case over a strong, tough core.
Name the three methods of case hardening
Carburizing, cyaniding, and nitriding
Explain the special characteristics of Alclad 2024-T4
“Alclad and pureclad” are used to designate sheets that consist of an aluminum alloy core coated with a layer of pure aluminum to a depth of approximately 5.5 percent on each side.
Explain the construction of a honeycomb composite material
Honeycomb’s core is made up of paper, nomex, carbon, fiberglass, or metal. The core is sandwiched together between high density laminate or solid face and back and held together with an adhesive.
Compare the tensile strength of a composite aircraft structure and those made of steel or aluminum
Composite aircraft structures have a tensile strength 4 to 6 times that of steel or aluminum.
Explain the term “ice box rivets”
Ice box rivets are 2017-T and 2024-T rivets that have been annealed, and must be kept refrigerated until they are to be driven. This refrigeration delays the hardening of the rivets.
When are “ice box” rivets used?
They are used in aluminum alloy structures where more strength is needed than is obtainable with the same size 2217-T rivet.
Name the two types of heat treatments applicable to aluminum alloys
Heat treatment and precipitation heat treatment.
Artificial aging is another term for what type of heat treatment?
Precipitation heat treatment
Why are corked gaskets the best choice for mating rough surfaces?
They best conform to the uneven or varying space
Name the classes of bolt threads and explain what the differences are between them.
The class of a thread indicates the tolerance allowed in manufacturing. Class 1 is a loose fit, class 2 is a free fit, class 3 is a medium fit and class 4 is a close fit.
When are self-locking nuts used on the aircraft?
To provide tight connections, which will not shake loose under severe vibrations.
What are AN960 and AN970 washers used for?
These plain washers are used to form a smooth bearing surface and act as a shim to obtain the correct grip length for a bolt and nut assembly, prevent damage to the surface material and provide protections against galvanic corrosion
Explain the correct way to line up a hole for use with a cotter pin
Change the washers and try again
Define grip length or range
the length of the unthreaded portion of the bolt shank.
Explain how to determine the correct grip length or range when selecting the bolt
Bolt grip lengths should be equal to the material thickness of the material with the hook scale inserted through the hole. Once this measurement is determined, select the correct grip range by referring to the charts provided by the manufacturer.
Explain the standard positioning for aircraft bolts when installed on an aircraft and why
Unless otherwise specified or required, aircraft bolts must be installed with the head of the bolt facing upward, inward, forward directions. This position prevents the bolt from slipping out if the nut is lost.
Explain the use of helicoils
Used to restore damaged threads.
What specialty fastener is best suited to secure an aircraft cowling
Camloc fasteners are used to secure aircraft cowlings and fairings.
Explain the primary benefit of an MS33737 instrument nut
It reduces magnetic influences in the cockpit.
Explain the industry standard for securing fasteners with safety wire
Arrange the wire so that if the bolt or screw begins to loosen, the force applied to the wire is in the tightening action (Backward S).
