Materials and Processes Flashcards
What is a suitable nondestructive method for detecting surface cracks in aluminum castings and forgings?
The dye penetrant inspection method detects surface cracks with equal success on aluminum, magnesium, brass, copper, and titanium. It can also be used on ceramics, plastics, and glass.
Briefly describe the steps to be taken when performing a dye penetrant inspection.
Thoroughly clean the metal surface, dry completely, and apply the penetrant. Remove the penetrant from the surface, dry the part, and apply the developer. Inspect and interpret the results.
Briefly describe the procedure for performing a magnetic particle inspection.
Thoroughly clean all grease, oil and dirt from the metal part which must be of magnetic material such as iron or steel. Magnetize the part and then apply the ferromagnetic particles, either held in liquid suspension or in dry powder form, to the area to be inspected. If a discontinuity is present, the magnetized particles will form a pattern in the approximate shape of the discontinuity.
What is the general rule for using self-locking nuts?
Do not use self-locking nuts at joints which subject either the nut or bolt to rotation.
What type of cable is used in primary flight control systems?
Extra flexible 7 x 19 cable. Minimum Diameter 1/8”
How can the correct “grip length” of a bolt be determined?
The grip length is the unthreaded portion of the bolt shank. Generally speaking, the grip length should equal the total thickness of the material being bolted together.
What is the smallest cable that can be used in primary control systems?
Federal regulations state that no cable smaller than one-eighth inch (1/8”) in diameter may be used for this purpose.
What should be the depth of penetration when making a fillet weld?
Penetration should be 25 to 50 percent of the thickness of the base metal.
What should be the width of the weld bead and depth of penetration when making a butt weld?
The bead width should be 3 to 5 times the thickness of the base metal and there should be 100 percent penetration
What system is used to identify AN-type aircraft bolts?
Aircraft bolts have code markings on the bolt heads for identification.
What are the steps for solution heat-treating aluminum alloys?
The alloy must be heated to a predetermined temperature, heat soaked for a specified period of time, and then rapidly quenched to a relatively low temperature.
In what state is aluminum alloy immediately after solution heat-treating and quenching?
The alloy is in a comparatively soft state, so the material must be naturally aged or precipitation hardened.
What is done to prevent certain aluminum alloy rivets from becoming hard after heat-treating and quenching?
The rivets are stored in a refrigerator at a temperature lower than 32°F. The rivets will remain soft for several days.
What are the characteristics of a cold weld?
A cold weld has improper penetration and cold laps caused by the insufficient heat. It appears rough and irregular and its edges are not feathered into the base metal.
What tool is used to measure the outside dimensions of shafts, thickness of sheet metal stock, diameter of drills, and for many other similar applications?
Outside micrometer calipers.
