MSE 220 VERIFIED STUDY GUIDE
Steels - Answers - Iron-Carbon alloyws
Plain Carbon Steels - Answers - contain only residual concentrations of impurities other
than carbon and a little manganese
Steel categories - Answers - -Low-Carbon Steels - Less than .25 wt % C. Strengthen by
cold work. Soft and weak but are ductile and tough. machinable, weldable, and least
expensive of all steels.
Microstructure: ferrite and pearlite.
-Medium-Carbon Steels - concentrations between .25 and .6 wt %. Micro structure is
tempered martensite.
High-Carbon Steels - concentrations between .6 and 1.4 wt % C. hardest, strongest,
and least ductile of carbon steels. Always used in hardened and tempered conditions.
Wear resistant (Cutting sharp edges).
Stainless Steels - Answers - Highly resistant to corrosion in variety of environments.
Concentration of at least chromium (11 wt%). Divided into three classes: martensitic,
ferritic, or austentitic.
Cast Irons - Answers - Carbon content above 2.14 wt % (usually between 3.0 and 4.5
wt %). Easily melted and amenable to casting. Most convenient fabrication technique.
Very brittle.
Gray Iron - Answers - Carbon and Silicon content; (2.5-4.0 wt% C and 1.0-3.0 wt% Si).
Graphite exists in form of flakes. Weak and brittle because of tips of flakes. Strength
and ductility high under compression loads. Effective in damping vibrational energy.
High resistance to wear. High fluidity in molten state, easy to cast with intricate shapes.
Casting shrinkage is low; least expensive of all metallic materials.
Ductile/Nodular Iron - Answers - Graphite forms in the shape of spherelike particles
instead of flakes. Adding magnesium and or cerium to gray iron before casting. Matrix
phase surrounding particles is pearlite or ferrite. Normally pearlite. Stronger and more
ductile than gray iron.
White Cast Iron - Answers - Low-silicon cast irons (less than 1.0 wt % Si) and rapid
cooling rates. Cementite forms instead of graphite. Very hard and wear-resistant
surface. Low ductility.
Malleable Iron - Answers - White iron is an intermediary in the production of this. Heated
between 800/900 and held for long time to produce graphite surrounded by ferrite or
pearlite.
, Ferrous Alloys - Answers - 1. Abundant in earths crust
2. Easy to process, extract, fabricate
3. Least expensive to produce.
Limitations:
1. high density
2. low electrical conductivity properties
3. susceptible to corrosion in common environments.
Cast Alloys - Answers - So brittle that forming or shaping by appreciable deformation is
not possible and must be casted
Wrought Alloy - Answers - Can be amenable to mechanical deformation
Brasses - Answers - Copper + substitutional impurity zinc: FCC crystal structure. soft,
ductile, easily cold worked.
Bronzes - Answers - Copper + substituional impurity tin: strong than brasses. High
degree of corrosion resistance.
Aluminum alloys - Answers - Low density, high electrical and thermal conductivities, and
resistance to corrosion. High ductility. FCC crystal structure.
Magnesium Alloys - Answers - Lowest density of all structural metals. HCP crystal
structure. soft, low elastic modulus. Unstable and susceptible to corrosion. Fine powder
ignites easily when heated in air.
Titanium - Answers - Low density, high melting point, extremely strong, highly ductile
and easily forged and machined. HCP crystal structure.
Refractory Metals - Answers - Has extremely high melting temperatures because of
strong interatomic bonding.
Superalloys - Answers - Can withstand exposure to severely oxidizing environments
and high temperatures for reasonable time periods.
Noble Metals - Answers - Expensive, soft, ductile, oxidation resistant. Used in jewelry.
Nickel alloys - Answers - Highly resistant to corrosion.
Hot Working - Answers - Deformation is achieved at temperature above that at which
recrystalization occurs
Cold Working - Answers - Deformation below recrystalization temperatures. Increases
strength, decreases ductility because of metal strain hardens. Higher quality than hot
working.
Steels - Answers - Iron-Carbon alloyws
Plain Carbon Steels - Answers - contain only residual concentrations of impurities other
than carbon and a little manganese
Steel categories - Answers - -Low-Carbon Steels - Less than .25 wt % C. Strengthen by
cold work. Soft and weak but are ductile and tough. machinable, weldable, and least
expensive of all steels.
Microstructure: ferrite and pearlite.
-Medium-Carbon Steels - concentrations between .25 and .6 wt %. Micro structure is
tempered martensite.
High-Carbon Steels - concentrations between .6 and 1.4 wt % C. hardest, strongest,
and least ductile of carbon steels. Always used in hardened and tempered conditions.
Wear resistant (Cutting sharp edges).
Stainless Steels - Answers - Highly resistant to corrosion in variety of environments.
Concentration of at least chromium (11 wt%). Divided into three classes: martensitic,
ferritic, or austentitic.
Cast Irons - Answers - Carbon content above 2.14 wt % (usually between 3.0 and 4.5
wt %). Easily melted and amenable to casting. Most convenient fabrication technique.
Very brittle.
Gray Iron - Answers - Carbon and Silicon content; (2.5-4.0 wt% C and 1.0-3.0 wt% Si).
Graphite exists in form of flakes. Weak and brittle because of tips of flakes. Strength
and ductility high under compression loads. Effective in damping vibrational energy.
High resistance to wear. High fluidity in molten state, easy to cast with intricate shapes.
Casting shrinkage is low; least expensive of all metallic materials.
Ductile/Nodular Iron - Answers - Graphite forms in the shape of spherelike particles
instead of flakes. Adding magnesium and or cerium to gray iron before casting. Matrix
phase surrounding particles is pearlite or ferrite. Normally pearlite. Stronger and more
ductile than gray iron.
White Cast Iron - Answers - Low-silicon cast irons (less than 1.0 wt % Si) and rapid
cooling rates. Cementite forms instead of graphite. Very hard and wear-resistant
surface. Low ductility.
Malleable Iron - Answers - White iron is an intermediary in the production of this. Heated
between 800/900 and held for long time to produce graphite surrounded by ferrite or
pearlite.
, Ferrous Alloys - Answers - 1. Abundant in earths crust
2. Easy to process, extract, fabricate
3. Least expensive to produce.
Limitations:
1. high density
2. low electrical conductivity properties
3. susceptible to corrosion in common environments.
Cast Alloys - Answers - So brittle that forming or shaping by appreciable deformation is
not possible and must be casted
Wrought Alloy - Answers - Can be amenable to mechanical deformation
Brasses - Answers - Copper + substitutional impurity zinc: FCC crystal structure. soft,
ductile, easily cold worked.
Bronzes - Answers - Copper + substituional impurity tin: strong than brasses. High
degree of corrosion resistance.
Aluminum alloys - Answers - Low density, high electrical and thermal conductivities, and
resistance to corrosion. High ductility. FCC crystal structure.
Magnesium Alloys - Answers - Lowest density of all structural metals. HCP crystal
structure. soft, low elastic modulus. Unstable and susceptible to corrosion. Fine powder
ignites easily when heated in air.
Titanium - Answers - Low density, high melting point, extremely strong, highly ductile
and easily forged and machined. HCP crystal structure.
Refractory Metals - Answers - Has extremely high melting temperatures because of
strong interatomic bonding.
Superalloys - Answers - Can withstand exposure to severely oxidizing environments
and high temperatures for reasonable time periods.
Noble Metals - Answers - Expensive, soft, ductile, oxidation resistant. Used in jewelry.
Nickel alloys - Answers - Highly resistant to corrosion.
Hot Working - Answers - Deformation is achieved at temperature above that at which
recrystalization occurs
Cold Working - Answers - Deformation below recrystalization temperatures. Increases
strength, decreases ductility because of metal strain hardens. Higher quality than hot
working.
