Materials and processes Flashcards
What is suitable nondestructive testing method for detecting surface cracks on aluminum casing and forgings
The die penetrant inspection method to Detect surface cracks with equal success on aluminum, magnesium, press, copper and titanium. It can also be used on ceramics, plastic and glass
List the steps in a die penetrate inspection
- thoroughly clean the material surface. Two. Apply the penetrant for the specific 12 time. Three. Remove the penetrant with water and emulsifying cleaner. Four. Dry the part. Five. Apply to developer. Six. Inspect the results.
Describe the procedure for performing a magnetic particle inspection
Thoroughly clean all grease oil and dirt from the metal which must be a Farias material such as iron or steel. Magnetize the part 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, demagnetize particles will form a pattern in the approximate shape of the discontinuity
What are two types of self locking nuts
Fiber lock, elastic stop nuts
What is the general rule for using a self locking nut
Do not use self locking nuts at joints which are subject to rotation
What type of cable is used in primary control systems
Extra flexible 7 x 19 cable
How can the correct grip length of a bolt be determined
The grip length should equal the total thickness of the material being joined together. The grip of the bolt is the unthreaded portion of the bolt Shank
The length an AN Standard bolts are measured in what fraction
8
What does the triangle mean on the head of a steel bolt
Close tolerance bolt
What numbers are used for close tolerance bolts
AN– 173 Through AN- 186 For hex head bolts, and NAS-80 through NAS - 86 for countersunk
What is the difference between a standard bolt in a close tolerance bolt
A close tolerance bolt is machined two more precise dimensions and is used in high performance applications
A solid rivet diameter is always measured in what fraction
32nd of an inch
Describe a Rivnut
Threaded body that is riveted to the aircraft structure
What is the purpose of a channel nut and nut plate
Both nuts allow a screw or bolt to be installed without needing to hold the nut with a wrench
What are common materials for Cotter pins to be made from
Low carbon steel, and stainless steel
What is the smallest cable that can be used in primary control systems
1/8 inch in diameter
What should be the depth of penetration when making a fillet weld
Penetration should be 25 to 50% of the thickness of a base metal
What precision measuring instruments are used to measure outside dimensions
Outside micrometer and veneer calipers
What term describes a metal that is based on iron
Ferrous alloy
What should be the width of the weld bead and depth of penetration when making a butt weld
The beed with should be 3 to 5 times the thickness of the base metal and there should be 100% penetration
What system is used to identify AN type Aircraft bolts
Aircraft bolts have code markings on the bolt head for identification. Bolt diameter is measured in sixteenths of an inch and length is measured in eighths of an inch
What is the difference between a close tolerance and regular AN bolts
Close tolerance bolts are used in applications where the bolted joint is subjected to severe vibrations and load reversals. Also, close tolerance bolts our machine to more precise standards and must be driven in by a hammer
What are the steps for solution heat treating aluminum alloy’s
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 quenched
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. They are also called icebox rivets
What do you rivet had markings Indicate
The Alloway of the rivet
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 area of the weld
Why should Steel be normalized after welding or machining
To remove internal stresses of the metal, thereby reducing brittleness
What are two methods of case hardening
Carburizing and nitriding
What are the Characteristics of a cold weld
A cold weld has improper penetration and cold lapse caused by insufficient heat. It appears rough and irregular and it’s edges are not feathered into the Base metal
What tools are used to measure the outside dimensions of shafts, thickness of sheet metal stock, diameter of drills, and for many other similar applications
Outside micrometer or caliber
What should be used to make a visible inspection of a weld
A magnifying glass of at least 10 power
Name some types of nondestructive testing used on nonferrous materials
Eddy current, die penetrant, x-ray, coin tap, and visual inspection
What is the most common type of corrosion
Surface corrosion
What does a 1/4- 20 Bolt mean
The bolt diameter and thread count
