EVERYTHING Flashcards
1
Q
What does EMC stand for?
A
Engineering, Materials and Components
2
Q
What two forms are available of stainless steel?
A
Wrought and cast iron
3
Q
Stainless steel does not usually have less than how much iron?
A
50%
4
Q
What is Galvanic Corrosion?
A
2 dissimilar metals in contact with each other in the presence of an electrolyte
(One is the anode, other is cathode)
5
Q
Does the anode or cathode corrode?
A
Anode
6
Q
What are the 3 main crystalline lattice structures?
A
FCC, BCC, and HCP
7
Q
What crystalline lattice structure is considered ductile and give an example.
A
FCC, ex. iron
8
Q
What crystalline lattice structure is considered strong and hard and give an example.
A
BCC, ex. iron
9
Q
What crystalline lattice structure is prone to hardening and give an example.
A
HCP, ex. zinc
10
Q
What is polymorphic/allotropic?
A
Can exist in more than one crystalline structure.
Ex. Iron - BCC to FCC when heated
11
Q
What are the properties of a metal that is more ferrite?
A
Softer/more ductile
12
Q
What are the properties of a metal that is more cementite?
A
More hard/brittle
13
Q
Coarse grain structures are stronger or weaker than fine grain structures?
A
Weaker. Fine grain structures are stronger
14
Q
What type of grain structure is better for machinability?
A
Coarse-grained but the surface quality isn’t as good
15
Q
What is tensile strength?
A
Max stress applied by pulling/stretching prior to fracture
16
Q
What is the lightest of all commercial metals?
A
Magnesium
17
Q
Titanium is how much lighter than steel?
A
45%
18
Q
What material is the best conductor of heat and electricity?
A
Silver
19
Q
What two elements make up air and what percentage of each?
A
19% oxygen and 81% nitrogen
20
Q
What is the triple point?
A
When material can exist as a solid, liquid and a gas in equilibrium
21
Q
How do you know the atomic number?
A
Number of protons
22
Q
How do you know the mass number?
A
Protons plus neutrons in the nucleus
23
Q
What is the mass of a proton?
A
One
24
Q
What determines the element?
A
Number of protons
25
How much does an electron weigh?
1/1840 of a proton
26
What is the mass of a neutron?
One
27
What is the only element without a neutron?
Hydrogen with one proton
28
Define element:
Pure substance with chemically identical atoms
29
Define compound:
2+ elements chemically combined
30
Define ionic bond:
The attraction between 2 oppositely charged ions
31
Define covalent bond:
A chemical bond of a stable balance between attractive/repulsive forces
32
Define metallic bond:
Electromagnetic interaction between delocalized electrons and positive ions
33
Define amorphous:
Solid as such as glass that solidify but don’t take a crystalline structure
34
What is the carbon content of wrought iron?
Usually below 0.08%
35
What is the carbon content of cast iron?
Between 2 and 6.67%
36
Define composite and give 3 examples
2+ elements to produce a different substance. 1) polymer 2) metal 3) ceramic
37
What is a common example of a laminate material?
Fiberglass
38
Define polymorphic/allotropic:
Can exist in more than one crystalline structure
39
What does the equilibrium phase diagram show us?
What happens to a material by increasing the temp/carbon
40
What is the opposite of strength?
Ductility
41
Define hardness:
Ability to withstand surface indentation
42
Define impact resistance in one word:
Toughness
43
If a material is more ferrite, it will be…
Softer and more ductile
44
If a material is more cementite it will be…
Harder and more brittle
45
Austentite only exists at a high temp of between…
910 and 1400 degrees C
46
Ferrite is ferromagnetic below what temp?
768 degrees C
47
What type of grains are the strongest?
Fine grained
48
What type of grain can be more easily deformed?
Coarse grained
49
What type of grains machine better?
Machinability but surface quality isn’t as good
50
What type of grain ferrous material is easier to harden by heat treat than the other of same composition?
Coarse grained
51
Define tensile strength:
Max strength applied by pulling/stretching prior to failure
52
Define fatigue strength:
Ability to undergo cyclic stresses without failure
53
Define yield strength:
The stress a material can withstand without permanent deformation OR the point at which it will no longer return to original dimensions
54
Define discontinuity:
An interruption in normal physical structure/configuration of an article
55
Define pipe:
Inadequate amount of molten metal as ingot solidifies (not enough)
56
Define blowhole:
Multiple porosities that have joined, bursting through surface and into each other
57
When multiple porosities or blowholes are present and the material has been rolled, what are they referred to as?
Seams
58
Define stringers:
Inclusions that’s have been thinned and lengthened in direction of rolling or any other further process of operation
59
What is added to remove oxygen in the deoxidization of steel processing?
Silicon and aluminum
60
What is added to remove oxygen from steel processing?
Silicon and aluminum
61
5 Common Ingot Discontinuities:
1) blowhole
2) centreline shrinkage
3) segregation
4) porosity
5) inclusions
62
Which furnace is for primary processing and which is for secondary?
Primary: Blast Furnace
Secondary: Open Hearth Furnace (OHF)
63
What is generally what happens when pre-treating steel?
Oxygen forced into molten metal to push out carbon
64
In CONTINUOUS CASTING, molten metal is solidified into 1 of 3 things. What are the 3 things?
Billet, bloom or slab
65
Define billet:
Steel shape whose cross-sectional area is less than 36 square inches
66
Define bloom:
Larger than 36 square inches
67
Define slab:
Rectangular steel shape with width at least 3x it’s thickness
68
Inherent discontinuities happen during what process?
Casting
69
Define cheek:
Intermediate flash inserted between cope and drag to help in moulding difficult shapes
70
Define core:
Separate piece inserted into cavity to form an opening in casting
71
Define chaplets:
Small metal pieces used to hold the core in place
72
Define progressive solidification:
Freezing of liquid is from outside towards centre
73
Define directional solidification:
Freezing of liquid from one part of casting to another
74
Define what a chill is the casting process:
Device made from metal, inserted into mould to hasten solidification
75
Define segregation:
An irregular distribution of molten metal. Alloying elements didn’t blend properly
76
Define cold shut:
Different streams of metal, already cooling but not fusing together
77
Define cold shot:
Rapidly poured metal causing turbulence and not fusing (metal splashing on sides of walls which dry before the rest)
78
Define a hot/cold crack:
Lots of stress pulling on each other
79
Define misrun:
Not enough molten metal
80
What casting discontinuity is found commonly in thick to thin section transitions or abrupt changes in section?
Hot tears
81
What is the result of cold working?
A harder product with lower ductility
82
Define forging:
Metal is shaped by individual and intermittent application of pressure
83
What happens to grains in the rolling process?
They’re elongated and compressed
84
Define extrusion:
Compressing metal and polymer beyond elastic limit then forcing them through and opening or die
85
What is the reverse process of extruding? And define it:
Drawing: pulling metal though a die
86
What are the 4 types of stress?
Shear, tensile, compressive and torsional
87
Describe what a lamination would look like:
Flat, extremely thin and generally parallel
88
What is caused by non metallic inclusions in billets/blooms that have been thinned and lengthened?
Stringers
89
What casting discontinuity is shaped like chevrons?
Cupping (serious of internal ruptures)
90
Describe a forging lap:
Smooth, wavy lines that are not usually very pronounced but do not adhere to base
91
Describe hydrogen flakes:
Short, internal fissures that are super thin and aligned parallel with the grain
92
Pickling is done prior to what?
Plating/cladding
93
How are flash line tears caused?
Improper trimming of flash or a dull trimming tool
94
How are grinding cracks positioned on the material?
Right angles to the direction of grinding
95
What 2 discontinuities are caused by diffusion of hydrogen during operations?
Pickling and plating cracks
96
For a fracture to occur, what must happen to the material?
Material is pushed past ELASTIC LIMIT resulting in plastic deformation
97
How many different stresses are there and what are they?
1) tension, 2) compression, 3) bending, 4) shear, 5) torsion
98
What is the factor of safety and how is it achieved?
The relationship between actual stress and ultimate strength (divide actual stress from unlimited strength)
99
Define fatigue:
Progressive stress caused by cyclic loading
100
If a material has reached its elastic limit or yield point, what will happen to it?
Won’t return to original shape
101
Plastic deformation is when a load…
Exceeds elastic limit/yield point
102
What is the purpose of the stress-strain curve?
To identify a material as ductile or brittle
103
Brinell, Rockwell and vickers are all hardness tests that are apart of what subcategory?
Resistance to penetration
104
What does the brinell hardness test use?
A 10 mm diameter hard steel ball OR carbide sphere of spherical load
105
What does the Rockwell hardness test use?
Depth of an impression from a diamond cone shaped indenter
106
What is measured in the vickers hardness test?
Measures microhardness in shallow penetration using a square shaped pyramid indenter
**most accurate
107
Cold working does what to the crystal structure?
Compacts crystal structure
108
Elevating temps start to do what to the grains?
Reform the grains
109
Normalizing is used after casting, rolling or forging to do what 3 things?
1) refine grain size, 2) produce a uniform microstructure and 3) improve mechanical properties
110
What type of electrode provides a filler metal?
Consumable electrode
111
What is not melted in flow bonding welding?
Base metal
112
Define cyclic loading:
Repeated/fluctuating stresses BELOW tensile strength
113
What initiates fatigue cracking?
Cyclic loading
114
Define over stress:
Exceeds ultimate strength
115
4 typical service related discontinuities:
1) fatigue cracks/failure
2) over-stress cracks/failure
3) creep failure
4) thermal fatigue failure
116
Fatigue cracks/failure are formed under what?
Cyclic stress
117
Over-stress cracks/failure are what type of failure?
Mechanical
118
Define creep failure:
Tendency of materials to move/deform permanently while under stress
119
Why does thermal fatigue failure happen?
Fracture from presence of temp gradients which will vary with time
120
What causes erosion corrosion?
An aggressive chemical environment and high fluid velocity
121
Define cavitation:
Implosion in cavities of liquid against metal
122
Explain filliform:
Localized and in high humidity conditions.. wormlike appearance
123
Define corrosion fatigue:
Fluctuated stress in a corrosive environment
124
Define stress-corrosion cracking:
Metal subject to constant low TENSILE stresses in corrosive environment
125
Does the anode or the cathode corrode?
Anode
126
Name 3 common anodes:
Zinc, magnesium and aluminum
127
The cathode acts as a what and removes electrons from metal?
Depolarizer
128
Name 5 common cathodes:
Stainless steel, silver, gold, platinum and copper
129
Describe what happens in galvanic corrosion:
Electrons leave the corroding material (anode) and enter the non corroding material (cathode) where negative ions are formed
