Introduction And Ferrous Materials Flashcards

1
Q

What is the definition of density?

A

The measure of mass per unit volume

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2
Q

What is the definition of fatigue?

A

When a metal is subjected to cyclic loads, it will start to crack after sufficient repetitions

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3
Q

What is the definition of elasticity?

A

When a material returns to its original shape after the deforming force has been removed

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4
Q

What is the definition of Unit Stress?

A

The force per unit area

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5
Q

Name the three simple stresses

A

Tensile
Compressive
Shear

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6
Q

What is combined stress?

A

A combination of tensile and shear stresses
Or
A combination of compressive and shear stresses

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7
Q

What is tensile stress?

A

The stretching or lengthening effect on a material

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8
Q

What is compressive stress?

A

The compressive or shortening effect on a material

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9
Q

What is shear stress?

A

The effect caused by layers on a material to slide over each other from opposite directions

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10
Q

What does Poisson’s Ratio state?

A

That the more the material is stretched, the thinner the material gets

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11
Q

What is the definition of hardness?

A

The ability to resist penetration/wear or cutting action

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12
Q

What is the definition of strength?

A

The ability to withstand forces which tend to deform the metal in any direction

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13
Q

What is the definition of plasticity?

A

The ability for a metal to be reshaped

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14
Q

What is the definition of ductility?

A

The ability to be drawn (stretched) into thinner sections without breaking

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15
Q

What is the definition of malleability?

A

The ability of a material to be beaten, rolled or stretched into a new shapw without breaking

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16
Q

What is the definition of toughness?

A

The ability to deform without breaking

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17
Q

What is the definition of Brittleness?

A

The ability to break easily when deformed/hammered

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18
Q

What is the definition of conductivity?

A

The ability to transmit heat or energy

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19
Q

What is the definition of durability?

A

The ability for a metal to withstand forces applied over a period of time

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20
Q

What are metallic materials?

A

A substance containing metal or a metal itself

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21
Q

What is a non-metallic material?

A

A substance containing no metal

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22
Q

What is a ferrous material?

A

A substance containing iron or any alloy that also contains iron

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23
Q

What is a non-ferrous material?

A

A metal which contains very little or no iron

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24
Q

What are the 4 elastic properties?

A

Elastic limit
Yield Strength
Ultimate Tensile Strength
Breaking Point of Sample

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25
Q

What is the Elastic Limit?

A

The maximum point of stress to which a material may be subjected and still return to its original shape.

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26
Q

What is the Yield Strength?

A

The maximum stress that can be applied without permanent deformation

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27
Q

What is the Ultimate Tensile Strength?

A

The maximum value of Tensile Stress that a material can withstand without breaking

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28
Q

What is the Breaking Point of a Sample?

A

The Modulus of Elasticity : the ratio of stress to strain within the proportional limit of a material in tension or compression

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29
Q

What are the three lightweight materials used for aircraft?

A

Aluminium
Magnesium
Titanium

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30
Q

What is a crystal?

A

A rigid body in which the constituent particles are arranged in a repeating system

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31
Q

What is a basic building block of a crystal called?

A

A Unit Cell

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32
Q

What does BCC stand for and how many atoms does it have in its unit cell?

A

Body centred cubic

9 atoms on the corners of the cube and one in the centre

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33
Q

What does FCC stand for and how many atoms are in its unit cell?

A

Face centred cubic

14 atoms on the corners and the centre of each face

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34
Q

What does HCP stand for and how many atoms does it have in its unit cell?

A

Hexagonal Close Packed

17 atoms

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35
Q

Name some examples of FCC types

A
Iron if ABOVE 910 degrees Celcius
Aluminium
Copper
Gold
Nickel
Silver
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36
Q

Name some examples of BCC types

A

Iron if BELOW 919 degrees Celcius

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37
Q

Name examples of some HCP types

A

Cobalt
Magnesium
Titanium
Zinc

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38
Q

What is an example of a ferrous material?

A

Steel

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39
Q

What is the base material for steel?

A

Iron

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40
Q

What is iron primarily alloyed with to make steel?

A

Carbon

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41
Q

What are characteristics of pure iron?

A

Soft
Malleable
Ductile

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42
Q

How is cast iron formed?

A

Molten iron alloyed with 2% of carbon and is poured into a mould

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43
Q

How is steel made?

A

Pure iron is melted in a blast furnace and introduced to carbon with other alloying elements to achieve desired characteristics

44
Q

Why is cast iron not favourable?

A

It is not strong

45
Q

Name some examples of alloying ingredients for steel and their alloying properties

A

Carbon - primary hardening agent
Sulphur - decreases ductility
Silicon - de oxidiser
Phosphorous - increases strength and hardness
Chromium - increases corrosion and oxidisation resistance

46
Q

What are the carbon percentages for LCS, MCS and HCS?

A

LCS - 0.1 -0.3%
MCS - 0.3 - 0.5%
HCS - 0.5 - 1.05%

47
Q

How are the types of steels represented?

A

As a 4 digit number

48
Q

What do the first and last 2 number denote in the material designation?

A

First 2- steel and alloys used

Last 2 - the % of carbon

49
Q

What are the designations based on?

A

The AISI numbers and SAE numbers

50
Q

What does AISI mean?

A

American Iron and Steel Institute

51
Q

What does SAE stand for?

A

System of Automated Engineers

52
Q

What must steel have for heat treatment to happen?

A

Must have carbon

53
Q

What type of heat treatment is used to decrease the hardness of steel?

A

Tempering

54
Q

What is the process to harden steel?

A

The material is heated above critical temperature allowing carbon to dispense uniformly in the iron matrix
The alloy is then cooled rapidly by quenching it in a quenching medium

55
Q

What are the three types of quenching mediums?

A

Water
Oil
Brine

56
Q

What is the most rapid quench medium?

A

Brine

57
Q

What is the steel known as if the quench is too quick?

A

Martensitic

58
Q

What characteristics does a martensitic structure have?

A

It is the hardest alloy

Too brittle for aircraft use

59
Q

What affects the hardness of steel?

A

The amount of carbon

60
Q

If there is more carbon in steel, the steel is…

A

More hard

61
Q

What are the different types of heat treatment?

A
Tempering
Annealing
Hardening
Normalising
Quenching
62
Q

What is annealing?

A

Heating a material and allowing it to cool slowly to increase softness and toughness and relieve internal stresses

63
Q

What is normalising?

A

When you heat steel to 100F above its upper critical unit, soak it for a given time and then cool it at room temp

64
Q

What are the names of the groups that steel is divided into depending on their structure?

A

Ferrite
Austenite
Cementite
Pearlite

65
Q

What are the three GENERAL groups that steel is divided into based on their structure ?

A

Ferrite
Austenite
Martensitic

66
Q

What does CRES stand for?

A

Corrosion Resistant Steel

67
Q

What process makes a substance less corrosive?

A

The addition of Chromium

68
Q

How are CRES identified?

A

By 3 digit numbers

200
300
400

69
Q

What are the 200 and 300 series known as?

A

Austenite

70
Q

What are the 2 types of 400 series known as?

A

Ferrite

Martensitic

71
Q

What type of series is commonly used in aircraft?

A

300 Austenite

72
Q

What are the 4 disadvantages of CRES?

A

Difficult to cut
Greater coefficient of expansion
Experienced technicians required
Not suitable in high temperature environments

73
Q

What sort of alloy is an Austenite?

A

Chromium-nickel and chromium-nickel-manganese alloys

74
Q

What sort of properties does an Austenite have?

A
18% or more chromium than nickel 
3.5%-22% of nickel
Contains stabilising alloys
200-300 series
Cold work
Strain hardened
Non magnetic
75
Q

What properties does a 400 series Ferrite have?

A
Contains 15% - 30% chromium
BCC
400 series
Small amounts if aluminium
Magnetic
Annealed and relatively low strength
76
Q

What properties does a Martensitic 400 series have?

A
400 series
12%-18% chromium
High Carbon content
Heat treatable
Least corrosion resistant
77
Q

Precipitation Hardening (steel) properties

A
Little carbon
15%-17% chromium
4%-7% nickel 
Solution heat treated
Can be hardened to very high strengths
Corrosion resistant
78
Q

What is the base alloy of a high strength low carbon steel?

A

Iron

79
Q

Name an advantage of High Strength Low Carbon Steels

A

Can be hardened to very high strengths

80
Q

What type of series is used on the landing gear?

A

300M

81
Q

What is hydrogen embrittlement and what sort of materials are mainly used for it?

A

The process for hydrogen to get into the grain boundaries of steel. The carbon reacts with the hydrogen in steel and increases the pressure and causes it to crack.

Mainly ferrous and titanium alloys

82
Q

What are the 2 steel alloy precautions?

A

Stress concentrations

Hydrogen embrittlements

83
Q

What are the precautions to take for stress concentrations?

A

The misuse of tools leading to scratches and general damage to surface finish

84
Q

What is a precaution to take for hydrogen embrittlement?

A

Ensure all precautions are taken to prevent embrittlement

85
Q

What are methods to surface protect CRES materials?

A

Cadmium plates
Zinc spray
Chromium

86
Q

What does surface protection on CRES materials do?

A

Avoid galvanic corrosion of light alloys

87
Q

What is galvanic corrosion potential?

A

The measure of how dissimilar metals will corrode when placed against each other in an assembly

88
Q

The further apart the metals in the corrosive list, the…?

A

The stronger the ability to corrode

89
Q

Which metal will corrode?

A

The metal higher in the list

90
Q

What is steel case hardening not suitable for?

A

Non- ferrous material

91
Q

What is case hardening?

A

The process of hardening the surface

92
Q

How many processes are there for case hardening and what are they?

A

4 processes

Carburising
Flame hardening
Induction hardening
Nitriding

93
Q

Which out of the two processes of case hardening is the most common?

A

Caruburising

94
Q

What is carburising?

A

Carburising produces a thin layer of high carbon steel around a softer low carbon steel core by introducing the material to carbon

95
Q

How many carburising methods are there and what are they called?

A

3 methods

Pack carburising
Gas carburising
Liquid carburising

96
Q

What is the process of pack carburising?

A

Heats up the component to 1700F temperatures whilst it is packed into a carbon rich materials such as charcoal. The carbon from the charcoal then penetrates the surface of the metal which causes it to harden

97
Q

For pack carburising, what is the quenching medium?

A

Quenching medium is oil

Water causes the hard case to peel

98
Q

What is the process of gas carburising?

A

Component is placed in a basket and then into a furnace and is passed through a suitable carbon rich gas. Carbon penetrates the surface and makes it harder.

99
Q

What is the process of liquid carburising?

A

The component is heated at a suitable temperature then immersed into a hot salt bath at 900 degrees C

100
Q

What is flame hardening?

A

Heat treatment for uniform compositions

The surface is heated to above upper temperatures by means of oxyacetylene torches and then quenched with a water jet built into an assembly

101
Q

What is induction hardening?

A

The whole circumference of a material is heated simultaneously by an induction coil and quenched with a water jet built into an assembly

102
Q

What is nitriding and its process?

A

The introduction of nitrogen to a substance For an improved surface finish

It heats up the material to 1000F in an ammonia rich environment. The ammonia breaks down and nitrogen is released and penetrates the surface of the material.

103
Q

The selection of materials should be a compromise between…?

A

The cost and quality

104
Q

What are the material characteristics of iron?

A

It is dense, soft and malleable

105
Q

What is the process used to relieve stress in high strength steel after machining?

A

Normalising

106
Q

If hydrogen embrittlement is suspected in a material, what should you do ?

A

Heat it up

107
Q

What does heating up the material do if you suspect hydrogen embrittlement?

A

Reverts the material back to its normal state