MAE exam 3 UPDATED Exam Questions
and CORRECT Answers
What is casting - CORRECT ANSWER - Metal is heated to a proper temperature and
melted. This molten metal is then poured into a cavity or mold to cool down and produce the
desired shape.
Important Considerations in Casting - CORRECT ANSWER - • Flow of the molten metal
into the mold cavity
• Solidification and cooling of the metal in the mold
• Influence of the type of mold material
casting Sizes - CORRECT ANSWER - centimeter, gram, meters, tons
What can casting create - CORRECT ANSWER - Parts that are difficult to machine.
complex shapes, hollow sections, and curved surfaces
Molding materials - CORRECT ANSWER - sand metal ceramics
Pouring methods - CORRECT ANSWER - gravity vacuum low pressure or high pressure
Requirements for casting - CORRECT ANSWER - Mold container
Melting process
Pouring Technique
Removal
Finishing
Casting Issues - CORRECT ANSWER - • Solidification Rates
• Fluid Flow
,• Heat Transfer • Defects
Solidification Rate : - CORRECT ANSWER - Where the molten metal is poured into a
mold and allowed to freeze into the desired final shape
Slow cooled joints - CORRECT ANSWER - are more ductile.
Fast-cooled joints - CORRECT ANSWER - fine grain structure and closer grain
boundaries, are more brittle.
Fluid flow gating system - CORRECT ANSWER - Conveys the liquid material to the
mold
Controls of fluid flow - CORRECT ANSWER - ◦ trapping contaminants: oxides and
inclusions (slag/dross)
◦ shrinkage
◦ speed of the liquid / turbulence (to reduce trapped air
Heat transfer - CORRECT ANSWER - When heat from the liquid metal transfers out of
the mold to the surrounding air.
importance of heat transfer - CORRECT ANSWER - • Critical when casting thin sections
• Premature chilling and solidification
What is Shrinkage - CORRECT ANSWER - contraction of molten metal as it cools prior
to solidification. Factors: phase change during liquid to solid, cooling and room temperature
What are risers - CORRECT ANSWER - Added reservoir to compensate for solidification
shrinkage.
, Defects of shrinkage - CORRECT ANSWER - -Metal oxide
Contamination (slag/dross) Shrinkage
Gas porosity
Casting Process issues during extraction - CORRECT ANSWER - Parting line
Drafts
Pattern allowances - CORRECT ANSWER - dimensional modifications that compensate
for shrinkage.
Expendable mold process - CORRECT ANSWER - Where the mold is destroyed to
remove part
Advantages of expendable mold - CORRECT ANSWER - more complex shapes
disadvantage of expendable mold - CORRECT ANSWER - Production rates limited and
time of casting
Permanent Mold Process: - CORRECT ANSWER - ◦ metal mold that can be used again.
advantages of permanent mold - CORRECT ANSWER - Higher production rates
Disadvantages of permanent mold - CORRECT ANSWER - geometries limited
Sand casting - CORRECT ANSWER - uses sand as the mold material cheap nearly all
alloys can be cast sizes range from small to large produced in foundries 70% of all metal castings
sand casting process - CORRECT ANSWER - prepare mold, pour metal, solidify, break
mold, remove casting, clean, heat treat
and CORRECT Answers
What is casting - CORRECT ANSWER - Metal is heated to a proper temperature and
melted. This molten metal is then poured into a cavity or mold to cool down and produce the
desired shape.
Important Considerations in Casting - CORRECT ANSWER - • Flow of the molten metal
into the mold cavity
• Solidification and cooling of the metal in the mold
• Influence of the type of mold material
casting Sizes - CORRECT ANSWER - centimeter, gram, meters, tons
What can casting create - CORRECT ANSWER - Parts that are difficult to machine.
complex shapes, hollow sections, and curved surfaces
Molding materials - CORRECT ANSWER - sand metal ceramics
Pouring methods - CORRECT ANSWER - gravity vacuum low pressure or high pressure
Requirements for casting - CORRECT ANSWER - Mold container
Melting process
Pouring Technique
Removal
Finishing
Casting Issues - CORRECT ANSWER - • Solidification Rates
• Fluid Flow
,• Heat Transfer • Defects
Solidification Rate : - CORRECT ANSWER - Where the molten metal is poured into a
mold and allowed to freeze into the desired final shape
Slow cooled joints - CORRECT ANSWER - are more ductile.
Fast-cooled joints - CORRECT ANSWER - fine grain structure and closer grain
boundaries, are more brittle.
Fluid flow gating system - CORRECT ANSWER - Conveys the liquid material to the
mold
Controls of fluid flow - CORRECT ANSWER - ◦ trapping contaminants: oxides and
inclusions (slag/dross)
◦ shrinkage
◦ speed of the liquid / turbulence (to reduce trapped air
Heat transfer - CORRECT ANSWER - When heat from the liquid metal transfers out of
the mold to the surrounding air.
importance of heat transfer - CORRECT ANSWER - • Critical when casting thin sections
• Premature chilling and solidification
What is Shrinkage - CORRECT ANSWER - contraction of molten metal as it cools prior
to solidification. Factors: phase change during liquid to solid, cooling and room temperature
What are risers - CORRECT ANSWER - Added reservoir to compensate for solidification
shrinkage.
, Defects of shrinkage - CORRECT ANSWER - -Metal oxide
Contamination (slag/dross) Shrinkage
Gas porosity
Casting Process issues during extraction - CORRECT ANSWER - Parting line
Drafts
Pattern allowances - CORRECT ANSWER - dimensional modifications that compensate
for shrinkage.
Expendable mold process - CORRECT ANSWER - Where the mold is destroyed to
remove part
Advantages of expendable mold - CORRECT ANSWER - more complex shapes
disadvantage of expendable mold - CORRECT ANSWER - Production rates limited and
time of casting
Permanent Mold Process: - CORRECT ANSWER - ◦ metal mold that can be used again.
advantages of permanent mold - CORRECT ANSWER - Higher production rates
Disadvantages of permanent mold - CORRECT ANSWER - geometries limited
Sand casting - CORRECT ANSWER - uses sand as the mold material cheap nearly all
alloys can be cast sizes range from small to large produced in foundries 70% of all metal castings
sand casting process - CORRECT ANSWER - prepare mold, pour metal, solidify, break
mold, remove casting, clean, heat treat
