Power Engineering 2A2 - Part 1 Exam Questions And Answers 100% Pass
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Power Engineering
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Power Engineering
Power Engineering 2A2 - Part 1 Exam
Questions And Answers 100% Pass
3 defined groups/categories of Metallurgy? - answer- Extractive
- Mechanical
- Physical
Define 'Extractive' Metallurgy. - answer- The study of extraction and purification of metals
from their ores. This includes a stepped pro...
Power Engineering 2A2 - Part 1 Exam
Questions And Answers 100% Pass
3 defined groups/categories of Metallurgy? - answer✔- Extractive
- Mechanical
- Physical
Define 'Extractive' Metallurgy. - answer✔- The study of extraction and purification of metals
from their ores. This includes a stepped process which can utilize Pyrometallurgy,
Hydrometallurgy or Electrometallurgy
Define Pyrometallurgy: - answer✔- Melting the ore in a furnace to release the metal
Define Hydrometallurgy: - answer✔- Dissolving the metal from the ore and recovering it as a
powder
Define Electrometallurgy: - answer✔- Dissolving the metal from the ore with the use of
electricity, plate the metal out of solution
What is Mechanical Metallurgy? - answer✔- The study of the techniques and mechanical forces
that shape and make finished forms of metal
- The study of the effects of stress, time and temperature
What is Physical Metallurgy? - answer✔- The study of the structure of metals - property of
metals are intimately related to their structures
- The physical metallurgy - or structure of a metal - can be changed by modifying chemical
composition, alloys and heat treatments
General characteristics of 'Metals'? - answer✔- Good conductors of heat and electricity
- Generally malleable and ductile
- Occur naturally in ores in the form of chemical compounds such as sulphides or oxides
What are Noble Metals? - answer✔- A metal that resists chemical action and does not corrode
or oxidize, and is not easily attacked by acids
Metals can exist in 3 common physical states depending on what? - answer✔Temperature and
pressure
Describe 'latent heat of fusion' in relation to metals. - answer✔- Het energy is added until
temperature no longer increases and the cohesive bonds holding the individual atoms together
break. This causes the metal to melt.
The main concern with metallurgy and industry is...? - answer✔- The complexity of the solid-to
liquid-to solid phase changes metals go through as they are refined
- The chemical and physical properties exhibited by them during these transitions
Define 'Unit Cells' in relation to the atomic structure of metals. - answer✔- When a metal
changes state from molten to solid, the rigid atomic structure of the atoms settles in 1 of 3
possible configurations:
1) Face-centered cubic (FCC) unit cells
2) Body-centered cubic (BCC) unit cells
3) Close Packed Hexagonal (CPH) unit cells
Face-centered Cubic (FCC) unit cells? - answer✔- 14 atoms make up the FCC cell
- Properties include: high ductility, low shear, low tensile strength, but good thermal and
electrical conductivity
Define Ductility: - answer✔- A measure of a metals ability to undergo significant plastic
deformation before rupture, which may be expressed as elongation or percent area reduction
from a tensile test.
- Often characterized by a materials ability to be stretched into a wire
Define Malleability: - answer✔- A materials ability to deform under compressive stress; often
characterized by a materials ability to form a thin sheet by hammering or rolling - without
fracture.
Both ductility and malleability are aspects of a materials...? - answer✔- Plasticity: the extent to
which a solid material can be plastically deformed without fracture
- The plasticity is dependant on temperature and pressure
Ductility and malleability are not always coextensive. True or False? - answer✔True. Gold is
both ductile and malleable while Lead has a very low ductility but high malleability.
What is Shear Strength? - answer✔- The strength of a material or component against the type
of yield or structural failure when the component fails in shear.
What is Shear Load? - answer✔- A force that tends to produce a sliding failure on a material
along a plane that is parallel to the direction of the force.
Metals that have FCC unit cell structures in the solid state? - answer✔- Gold, aluminum, silver,
lead, nickel, gamma iron (iron between temperatures 910 - 1390 deg.C)
# of atoms contained in a BCC structure? - answer✔9 atoms total
Characteristics of metals with the Body-centered cubic structure? - answer✔- High strength
- Low ductility
- Very resistant to shear deformities
Examples of BCC metals? - answer✔Chromium, tungsten, molybdenum, vanadium, alpha iron
(solid state iron below 910 deg.C) and delta iron (iron above 1390 deg.C)
How many atoms make up a Close-packed hexagonal structure? - answer✔17 atoms total
Characteristics of CPH structured unit cells? - answer✔Intermediate strength and Intermediate
ductility
Materials that possess CPH unit cell structures? - answer✔Zinc, magnesium, cadmium, titanium
When molten metal cools and solidifies, what action do unit cells take? - answer✔- Unit cells
become packed together to form 3 dimensional crystals that occupy a space lattice.
Further growth of these crystals form dendrites (evergreen tree looking crystals)
Properties of materials with small grain size? - answer✔- High tensile strength
- Highly ductile
Properties of materials with large grain size? - answer✔- High creep/deformation resistance
under constant loading
- More prone to cracking
Shear strength of metals is primarily determined by the type of Unit Cell Structure exhibited.
True or False? - answer✔True.
1) HIGH ATOM PACKED DENSITY FCC structures are very ductile (easy to elongate) with a low
shear strength - Ex.) Lead.
2) LOW ATOM PACKED DENSITY BCC structures have high hardness and a high shear strength.
Ex.) Iron
Opposite of metal hardness is...? - answer✔- A hard metal is does not possess TOUGHNESS.
- Hardness: resistance to deformation
What is Polymorphism and what does it have to do with metals? - answer✔- The ability of a
metal to change its unit cell structure through varying temperature ranges.
- Most metals exhibit this property; most important for the study of iron.
What is the allotropy of Iron? - answer✔- The change in atomic cell structure dependant on
temperature
- Various physical forms of metals can affect their: melting point, hardness, metal solubility, and
alloying chemistry.
Properties of pure Iron? - answer✔- Relatively soft
- Ductile
- Low strength
- Possesses few of the noble properties commonly associated with steel
Percentage carbon content in Carbon Steels and Cast Iron? - answer✔Carbon Steels: Alloys
containing 2% or less carbon
Cast Iron: 2% - 6% carbon
Three grades of Carbon Steel? - answer✔Low carbon steel: .04% to .30% carbon (mild steel)
Medium carbon steel: .31% to .60% carbon steel
High carbon steel: .61% to 1-1.50% carbon steel (tool steel)
Steel properties as carbon content increases? Decreases? - answer✔1) Hardness and brittleness
increase as carbon content increases
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