Materials and Processes Flashcards
Content in chapters 7, 10, and 11 for this course (108 cards)
1
Q
Define NDI
A
Nondestructive inspection
2
Q
Define NDT
A
Nondestructive testing
3
Q
What is the objective of NDI/NDT?
A
To determine the airworthiness of a component without damaging or rendering it unairworthy.
4
Q
What is liquid penetrant inspection?
A
A nondestructive test for defects open to the surface in parts made of any nonporous material.
5
Q
What are the two types of dye used in liquid penetrant tests?
A
Visible and flourescent
6
Q
What is in a visible penetrant kit?
A
Dye penetrant, dye remover emulsifier, and developer.
7
Q
What are the steps for performing a penetrant inspection?
A
- Clean the surface thoroughly.
- Apply penetrant.
- Remove penetrant with remover emulsifier or cleaner.
- Dry the part.
- Apply the developer.
- Inspect and interpret results.
8
Q
What can cause false indications in a liquid penetrant inspection?
A
Accumulations of unwashed penetrant or where parts press fit to each other.
9
Q
What are eddy current inspections used for?
A
Detect surface cracks, pits, subsurface cracks, corrosion on inner surfaces, and to determine alloy and heat-treat condition.
10
Q
What is ultrasonic inspection?
A
A NDI technique that uses sound energy moving through the test specimen to detect flaws.
11
Q
What are the two basic methods used for ultrasonic inspection?
A
Immersion testing and contact testing.
12
Q
Describe the immersion testing method used in ultrasonic inspection.
A
The part under examination and the search uni are completely immersed in a liquid couplant, such as water or other suitable fluids.
13
Q
Describe the contact testing method used in ultrasonic inspection.
A
The part under examination and the search unit are coupled with a viscous material, liquid, or a paste that wets both the face of the search unit and the material under examination.
14
Q
What are the three basic ultrasonic inspection methods?
A
Pulse echo, through transmission, and resonance
15
Q
How does the pulse echo ultrasonic inspection method detect flaws in a material?
A
Flaws are detected by measuring the amplitude of signals reflected and the time required for these signals to travel between specific surfaces and the discontinuity.
16
Q
How does the through transmission ultrasonic inspection method detect flaws in a material?
A
Through transmission inspection uses two transducers, one to generate the pulse and another placed on the opposite surface to receive it.
17
Q
What is the resonance ultrasonic inspection method?
A
The resonance method is used principally for thickness measurements when the two sides of the materal being tested are smooth and parallel and the backside is inaccessible.
18
Q
What is magnetic particle inspection?
A
A method of detecting invisible cracks and other defects in ferromagnetic materials.
19
Q
Where in a part is magnetic particle inspection able to detect defects?
A
On or near the surface.
20
Q
What are the two magnetizing operations used in magnetic particle inspection?
A
Circular magnetization and longitudinal magnetization.
21
Q
Why are two separate magnetizing operations required for magnetic particle inspections?
A
To locate a defect in a part it is essential that the magnetic lines of force pass approximately perpendicular to the defect.
22
Q
What types of plating can interfere with magnetic particle inspection?
A
Chromium and nickel plating generally do not interfere with indications of cracks open to the surface of the base metal, but prevent indications of fine discontinuities, such as inclusions.
23
Q
What are the two methods used in magnetic particle inspection?
A
Continuous inspection method and residual inspection method
24
Q
What inspection method is preferred for a magnetic particle inspection? Why?
A
Continous inspection method; the continous inspection method provides greater sensitivity than the residual inspection method.
25
What is the continuous inspection method when referring to magnetic particle inspection?
A part is magnetized and the indicating medium is applied while the magnetizing force is maintained.
26
What is the residual inspection method when referring to magnetic particle inspection?
A part is magnetized and the indicating medium is applied after the magnetizing force has been removed.
27
What are the principal distinguishing features of indications?
Shape, buildup, width, and sharpness of outline.
28
Define SAE
Society of Automotive Engineers
29
Define AISI
American Iron and Steel Institute
30
How is the thickness of sheet metal measured?
Thousandths of an inch.
31
What is considered low carbon steel?
Steel containing carbon in percentages ranging from 0.10 to 0.30 percent.
32
What is considered medium carbon steel?
Steel containing carbon in percentages ranging from 0.30 to 0.50 percent.
33
What is considered high carbon steel?
Steel containing carbon in percentages ranging from 0.50 to 1.05 percent.
34
What property changes occur when nickel is added to steel?
Nickel increases the hardness, tensile strength, and elastic limit of steel without appreciably decreasing the ductility.
35
What property changes occur when chromium is added to steel?
Chromium increases the hardness, strength, adds corrosion-resistant properties, and is particularly adaptable for heat-treated forgings.
36
What is the corrosion resistant steel most often used in aircraft construction known as and why?
18-8 steel; its content is 18 percent chromium and 8 percent nickel.
37
What is Inconel?
A nickel-chromium-iron alloy closely resembling stainless steel.
38
What are nonferrous aircraft metals?
All metals that have elements other than iron as its base or principal constituent.
39
What are the two general classes of aluminum?
Casting alloys (those suitable for casting in sand, permanent mold, or die castings). Wrought alloys (those which may be shaped by rolling, drawing, or forging).
40
What class of aluminum alloys are used most in aircraft construction?
Wrought alloys; being used for stringers, bulkheads, skin, rivets, and extruded sections.
41
Describe how the four-digit index system for wrought aluminum alloys works.
The first digit of a designation indicates the alloy type. The second digit indicates specific alloy modifications. The last two digits are used to indicate the hundredths of 1 percent above the original 99 percent designated by the first digit.
Examples: 1100 - 99.00% pure aluminum with one control over individual impurities. 1130 - 99.30% pure aluminum with one control over individual impurities. 1275 - 99.75% pure aluminum with two controls over individual impurities.
42
What are the three distinct groups used when designating wrought aluminum alloys?
The 1xxx group, the 2xxx through 8xxx group, and the 9xxx group (which is currently unused).
43
What is the major alloying element used in the formation of wrought aluminum designated as part of the 2xxx group?
Copper
44
What is the major alloying element used in the formation of wrought aluminum designated as part of the 3xxx group?
Manganese
45
What is the major alloying element used in the formation of wrought aluminum designated as part of the 4xxx group?
Silicon
46
What is the major alloying element used in the formation of wrought aluminum designated as part of the 5xxx group?
Magnesium
47
What is the major alloying element used in the formation of wrought aluminum designated as part of the 6xxx group?
Magnesium and silicon
48
What is the major alloying element used in the formation of wrought aluminum designated as part of the 7xxx group?
Zinc
49
What is the major alloying element used in the formation of wrought aluminum designated as part of the 8xxx group?
Other elements
50
How does titanium compare to aluminum and stainless steel in terms of elasticity, density, and elevated temperature strength?
Titanium falls between aluminum and stainless steel in regards to these properties.
51
Is titanium magnetic or nonmagnetic?
Nonmagnetic
52
The electrical resistance of titanium is comparable to what other material?
Stainless steel
53
What is copper primarily used for in aircraft?
In the electrical system for bus bars, bonding, and as safety wire.
54
What is heat treatment and what is its purpose?
Heat treatment is a series of operations involving the heating and cooling of metals in the solid state. Its purpose is to change a mechanical property, or combination of mechanical properties, so that the metal is more useful, serviceable, and safe for a definite purpose.
55
What are the most common forms of heat treatment for ferrous metals?
Hardening, tempering, normalizing, annealing, and casehardening.
56
What heat treatment options are available for nonferrous metals?
Most nonferrous metals can be annealed and many can be hardened. None can be tempered or normalized.
57
What is the only nonferrous metal that can be casehardened?
Titanium
58
What does hardening do to the properties of the metal?
Hardening increases the hardness and strength of the metal but makes it less ductile.
59
What does the hardening process consist of?
The hardening treatment consists of heating the steel to a temperature just above the upper critical point, soaking for the required length of time, and then cooling it rapidly by plunging the hot steel into oil, water, or brine.
60
What does tempering do to the properties of the metal?
Tempering reduces the brittleness imparted by hardening and produces definite physical properties within the metal.
61
What does the tempering process consist of?
Temperature is increased toward the low critical point. Tempering is always conducted at temperatures below the low critical point of the steel. The minimum time at the tempering temperature should be 1 hour, with 1 hour added for each additional inch of thickness. The steel is usually cooled in still air after being removed from the furnace.
62
What does annealing do to the properties of the metal?
Annealing produces a fine-grained, soft, ductile metal without internal stresses or strains. Annealing is the opposite of hardening.
63
What does the annealing process consist of?
The metal is heated to just above the upper critical point, soaked at that temperature, and cooled very slowly in the furnace.
64
What does normalizing do to the properties of the metal?
Normalizing removes the internal stresses set up by heat treating, welding, casting, forming, or machining.
65
What does the normalizing process consist of?
Heating the steel above the upper critical point and cooling in still air.
66
How is the soft or annealed condition in aluminum alloys designated?
The soft or annealed condition is designated O.
67
How is the strain hardened aluminum alloy designated?
Strain hardened condition is designated H.
68
How often are specifications marked on aluminum-alloy sheets?
Approximately every square foot of material.
69
What are the two different types of heat treatments used with aluminum alloys?
Solution heat treatment and precipitation heat treating.
70
What are the steps used in solution heat treatment?
1. Heating to a predetermined temperature.
2. Soaking at temperature for a specified length of time.
3. Rapidly quenching to a relatively low temperature.
71
What are the steps used in precipitation heat treatment?
1. Heating to a predetermined temperature.
2. Soaking at temperature for a specified length of time.
3. Rapidly quenching to a relatively low temperature.
4. Aging or precipitation hardening either spontaneously at room temperature, or because of a low temperature thermal treatment.
72
What is the annealing procedure for aluminum alloys?
Heating the alloys to an elevated temperature, holding or soaking them at this temperature for a length of time depending upon the mass of the metal, and then cooling in still air.
73
Why are aluminum alloys annealed?
Annealing leaves the metal in the best condition for cold working. It may be necessary to anneal a part several times during the forming process to avoid cracking.
74
What are the two major classes of transparent plastics?
Thermoplastic and thermosetting plastics.
75
What are the defining characteristics of thermoplastics?
Thermoplastic materials soften when heated and harden when cooled.
76
What are the defining characteristics of thermosetting plastics?
Thermosetting plastics harden upon heating, and reheating has no softening effect. These plastics cannot be reshaped once being fully cured by the application of heat.
77
Transparent plastics are manufactured in what two forms?
Monolithic (solid) and laminated.
78
What are laminated transparent plastics?
Laminated transparent plastics are made from transparent plastic face sheets bonded by an inner layer material.
79
What do composite materials consist of?
A combination of reinforcement, such as a fiber, whisker, or particle, surrounded and held in place by a resin forming a structure.
80
What are the advantages of composite materials?
* High strength-to-weight ratio
* Fiber-to-fiber transfer of stress allowed by chemical bonding
* Longer life than metals
* Higher corrosion resistance
* Greater design flexibility
* Bonded construction eliminates joints and fasteners
* Easily repairable
81
What are the disadvantages of composite materials?
* Inspection methods difficult to conduct, especially delamination detection
* Cost
* Very expensive processing equipment
* Great variety of materials, processes, and techniques
* Products often toxic and hazardous
* Lack of standardized methodology for construction and repairs
82
Define AN
Air Force-Navy
83
Define NAS
National Aircraft Standard
84
Define MS
Military Standard
85
Aircraft bolts, screws, and nuts are threaded in what series?
American National Coarse (NC) American National Fine (NF) American Standard Unified Coarse (UNC) American Standard Unified Fine (UNF)
86
How are threads designated?
By the number of times the thread rotates around a 1-inch length of a bolt or screw. Ex: 1/4-28 is a 1/4 inch diameter bolt with 28 threads per inch
87
What are the different classes of thread and what are their fits?
* Class 1 is a loose fit
* Class 2 is a free fit
* Class 3 is a medium fit
* Class 4 is a close fit
88
What classes of threads are used most in aviation?
Class 2 (most aircraft screws) Class 3 (most aircraft bolts)
89
What head styles are available for AN bolts?
hex head, Clevis, and eyebolt
90
What head styles are available for NAS bolts?
hex head, internal wrenching, and countersunk head
91
What head styles are available for MS bolts?
hex head and internal wrenching
92
What is a hex head aircraft bolt and what is it used for?
AN-3 through AN-20
An all-purpose structural bolt used for general applications involving tension or shear loads where a light drive fit is permissible.
93
What are close tolerance bolts and what are their designations?
Close tolerance bolts are machined more accurately than the general-purpose bolt. They are used in applications where a tight drive fit is required.
Hex head: AN-173 through AN-186
100º countersunk head: NAS-80 through NAS-86
94
What are internal wrenching bolts and what are their designations?
Internal wrenching bolts are fabricated from high-strength steel and are suitable for use in both tension and shear applications. When used in steel parts the bolt hole must be slightly countersunk. In Dural material, a special heat-treated washer must be used to provide an adquate bearing surface for the head.
MS-20004 through MS-20024 or NAS-495
95
How are AN standard steel bolts marked for identification?
AN standard steel bolts are marked with either a raised dash or asterisk or a single raised dash.
96
How are AN aluminum-alloy bolts marked for identification?
AN Aluminum-alloy bolts are marked with two raised dashes.
97
What does the bolt part number AN3DD5A represent?
* AN - Designates that it is an Air Force-Navy standard bolt
* 3 - Shank diameter in sixteenths of an inch (3/16")
* DD - Indicates the material is 2024 aluminum alloy
* 5 - Length in eighths of an inch (5/8")
* A - Indicates that the shank is undrilled.
98
What is a Clevis bolt?
The Clevis bolt has a round head and is either slotted to receive a common screwdriver or recessed to receive a phillips screwdriver. This type of bolt is used only where shear loads occur and never in tension.
99
What is an eyebolt?
The eyebolt is a special-purpose bolt used where external tension loads are to be applied. It is designed for the attachment of devices, such as the fork of a turnbuckle, a Clevis, or cable shackle. The threaded end may or may not be drilled for safetying.
100
What is a Jo-bolt?
Jo-bolt is a trade name for an internally threaded three-piece blind fastener. It consists of three parts: a threaded steel-alloy bold, a threaded steel nut, and an expandable stainless steel sleeve. When driving is complete, a portion of the bold breaks off.
101
What are lockbolts?
Lockbolts are used to attach two materials permanently. They are lightweight and are equal in strength to standard bolts.
102
What are the three types of lockbolts commonly used?
The pull type, the stump type, and the blind type.
103
What is a pull type lockbolt?
A type of lockbolt that requires a special pneumatic "pull gun" to be used for installation.
104
What is a stump type lockbolt?
A type of lockbolt that requires a standard pneumatic riveting hammer and a bucking bar for installation.
105
What is a blind type lockbolt?
A type of lockbolt that is used when only one side of the work is accessible and , generally, where it is difficult to drive a conventional rivet. It is installed with a special pneumatic "pull gun" like the pull type lockbolt.
106
What are the two general groups of aircraft nuts?
Non-self-locking and self-locking
107
What is a non-self-locking nut?
Nuts that must be safe tied by external locking devices such as cotter pins, safety wire, or locknuts.
108
