ME215 Exam 2 Study Guide Questions
with Actual Answers 2026-2027
Updated.
Annealing - Answer - Cooling in furnace
- Cost effective and time consuming
- The furnace imposes cooling conditions at all locations
- Result in identical structures and properties
Normalizing - Answer - Cooling in air
- Cooling will be different in different locations
- Properties will vary between the surface and interior
Process Anneal - Answer - Cooling in air
Recrystallization Anneal - Answer - Recrystallization is induced after a material has been cold
worked to reduce strain hardening effects
- Induces a change in size, shape and distribution
Stress-Relief Anneal - Answer - Reduces residual stresses
- Materials are heated and then slow cooled
- Microstructures and mechanical properties remain unchanged
Spheroidizing Anneal - Answer - Slow cooling
- For high carbon materials
Heat Treatment - Answer - A process of controlled heating and cooling of materials for the
purpose of altering their structures and properties, which changes in physical and mechanical
properties can be introduced with no change in product shape
Processing heat treatments are used to... - Answer - increase strength
- prepare the material for fabrication
- improve machining characteristics
- reduce forming forces
- restore ductility for further processing
,Heat Treatments for Nonferrous Metals - Answer Three purposes
- Produce a uniform, homogenous structure
- Provide a stress relief
Induce recrystallization
Solid-Solution Strengthening - Answer Substitutional solutions or interstitial solutions
Strain Hardening - Answer Increases strength by plastic deformation
Grain Size Refinement - Answer Metals with smaller grains tend to be stronger
Precipitation hardening or Age hardening - Answer Strength is obtained from a
nonequilibrium structure
Dispersion Hardening - Answer Dispersing second-phase particles through a base material
Phase transformations - Answer Heated to form a single phase at an elevated temperature
and subsequently transform to one or more low temperature phases upon cooling (austenite ->
martensite)
Precipitation Hardening - Answer - Most effective mechanism to strengthen nonferrous
metals
- Non-equilibrium heat treatment procedure
Process of Precipitation Hardening - Answer Three-step Sequence: solution treatment ->
quench -> aged
Coherency - A Coherent Precipitate - Answer The crystallographic planes of the parent
structure are continuous through the precipitate cluster, and the solute aggregate tends to
distort the lattice to a substantial surrounding regiong
Non-Coherency (Overage) - Answer Second phase particles have their own crystal structure
and distinct interphase boundaries
Overaging - Answer The decrease in hardness and strength of precipitation or age hardened
materials
, Aging Step - Answer Divide precipitation-hardening materials into two types: natural aging
materials (ages at room temperature) and artificial aging material (requires elevated
temperature to produce aging)
Tempering - Answer To sacrifice strength and hardness for ductility and toughness
Age Hardening - Answer To sacrifice toughness and ductility for strength
Continuous Cooling Transformations (CCT) - Answer The modification of ttt diagram, shows
the phase and composition of steels upon cooling as functions of temperature and time
Jominy Test - Answer The hardenability test - a material is heated and quenched from one
end, then hardness along the material length is determined
Carbon Content - Answer The larger carbon content the higher strength, the higher hardness
Alloy Additions - Answer Related to the amounts and types of alloying elements; Primary
reason to add an alloying element is to increase hardenability
Quench Media - Answer Quenchants are the medium in which a material is quenched
Stages of Quenching - Answer Formation of the vapor jacket -> Nucleate boiling phase ->
Conduction and convection
Quenchant Consideration - Answer - Water is an effective quenching medium because of its
high heat of vaporization and relatively high boiling point
- Brine is similar to water as a quenchant medium
- Oil is utilized if slower quenching rates are desired
- Water based polymer quenchants have properties between oil and water and brine
- Other slow cooling quenchants: Molten salt baths, cooling in air, bury the hot material in sand,
etc.
Residue Stress - Answer - Exist in a part independent of an applied stress
- Undesirable residual stresses result in cracking, warping, dimensional changes
Causes of dimensional changes during heat treatment - Answer - Thermal expansion during
heating and thermal contraction during cooling
- Volume expansion and contraction
with Actual Answers 2026-2027
Updated.
Annealing - Answer - Cooling in furnace
- Cost effective and time consuming
- The furnace imposes cooling conditions at all locations
- Result in identical structures and properties
Normalizing - Answer - Cooling in air
- Cooling will be different in different locations
- Properties will vary between the surface and interior
Process Anneal - Answer - Cooling in air
Recrystallization Anneal - Answer - Recrystallization is induced after a material has been cold
worked to reduce strain hardening effects
- Induces a change in size, shape and distribution
Stress-Relief Anneal - Answer - Reduces residual stresses
- Materials are heated and then slow cooled
- Microstructures and mechanical properties remain unchanged
Spheroidizing Anneal - Answer - Slow cooling
- For high carbon materials
Heat Treatment - Answer - A process of controlled heating and cooling of materials for the
purpose of altering their structures and properties, which changes in physical and mechanical
properties can be introduced with no change in product shape
Processing heat treatments are used to... - Answer - increase strength
- prepare the material for fabrication
- improve machining characteristics
- reduce forming forces
- restore ductility for further processing
,Heat Treatments for Nonferrous Metals - Answer Three purposes
- Produce a uniform, homogenous structure
- Provide a stress relief
Induce recrystallization
Solid-Solution Strengthening - Answer Substitutional solutions or interstitial solutions
Strain Hardening - Answer Increases strength by plastic deformation
Grain Size Refinement - Answer Metals with smaller grains tend to be stronger
Precipitation hardening or Age hardening - Answer Strength is obtained from a
nonequilibrium structure
Dispersion Hardening - Answer Dispersing second-phase particles through a base material
Phase transformations - Answer Heated to form a single phase at an elevated temperature
and subsequently transform to one or more low temperature phases upon cooling (austenite ->
martensite)
Precipitation Hardening - Answer - Most effective mechanism to strengthen nonferrous
metals
- Non-equilibrium heat treatment procedure
Process of Precipitation Hardening - Answer Three-step Sequence: solution treatment ->
quench -> aged
Coherency - A Coherent Precipitate - Answer The crystallographic planes of the parent
structure are continuous through the precipitate cluster, and the solute aggregate tends to
distort the lattice to a substantial surrounding regiong
Non-Coherency (Overage) - Answer Second phase particles have their own crystal structure
and distinct interphase boundaries
Overaging - Answer The decrease in hardness and strength of precipitation or age hardened
materials
, Aging Step - Answer Divide precipitation-hardening materials into two types: natural aging
materials (ages at room temperature) and artificial aging material (requires elevated
temperature to produce aging)
Tempering - Answer To sacrifice strength and hardness for ductility and toughness
Age Hardening - Answer To sacrifice toughness and ductility for strength
Continuous Cooling Transformations (CCT) - Answer The modification of ttt diagram, shows
the phase and composition of steels upon cooling as functions of temperature and time
Jominy Test - Answer The hardenability test - a material is heated and quenched from one
end, then hardness along the material length is determined
Carbon Content - Answer The larger carbon content the higher strength, the higher hardness
Alloy Additions - Answer Related to the amounts and types of alloying elements; Primary
reason to add an alloying element is to increase hardenability
Quench Media - Answer Quenchants are the medium in which a material is quenched
Stages of Quenching - Answer Formation of the vapor jacket -> Nucleate boiling phase ->
Conduction and convection
Quenchant Consideration - Answer - Water is an effective quenching medium because of its
high heat of vaporization and relatively high boiling point
- Brine is similar to water as a quenchant medium
- Oil is utilized if slower quenching rates are desired
- Water based polymer quenchants have properties between oil and water and brine
- Other slow cooling quenchants: Molten salt baths, cooling in air, bury the hot material in sand,
etc.
Residue Stress - Answer - Exist in a part independent of an applied stress
- Undesirable residual stresses result in cracking, warping, dimensional changes
Causes of dimensional changes during heat treatment - Answer - Thermal expansion during
heating and thermal contraction during cooling
- Volume expansion and contraction
