MAE 364: Exam 1 Review UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
How does solidification of alloys differ from solidification of pure metals? - CORRECT
ANSWER Solidification of pure metals takes place at constant temperature while
solidification of alloys takes place over a range of temperatures.
What does heat of fusion mean in casting? - CORRECT ANSWER In casting, the heat
of fusion is the amount of energy that is involved in the material's phase change from liquid
to solid. In other words, heat of fusion is the value of the amount of heat the metal dissipates
when changing phase from liquid to solid.
Identify the three sources of contraction in a metal casting after pouring - CORRECT
ANSWER 1.) Liquid shrinkage: contraction of the metal after pouring and/or when hot
liquid nears freezing temperature
2.) Solidification shrinkage: shrinkage during phase transformation from liquid to solid
3.) Solid shrinkage: the shrinkage when the casting is cooled from freezing temp to ambient
temperature
Indicate the mathematical equation for the flow curve. - CORRECT ANSWER The
mathematical equation for the flow curve is, σ= Kε^n; where σ=true stress, K=strength
coefficient, ε=true strain, and n=strain hardening exponent.
How does increasing temperature affect the parameters in the flow curve equation? -
CORRECT ANSWER Increasing the temperature decreases K, the strength coefficient
and n, the strain hardening factor.
Indicate some of the advantages of cold working relative to warm and hot working. -
CORRECT ANSWER Greater accuracy, better surface finish, high strength and
hardness, grain flow => desirable directional properties, no heating of work required
What is a tolerance? - CORRECT ANSWER A tolerance is defined as the total amount
by which a specified dimension is permitted to vary.
, What is the difference between a bilateral tolerance and a unilateral tolerance? - CORRECT
ANSWER A bilateral tolerance allows variation in both positive and negative
directions from the nominal dimension, whereas a unilateral tolerance allows the variation
from the nominal dimension to be either positive or negative, but not both.
What is accuracy in measurement? - CORRECT ANSWER Accuracy is the degree to
which the measured value agrees with the true value of the quantity of interest. It is a
measurement procedure that is absent of systematic errors.
What is precision in measurement? - CORRECT ANSWER Precision in measurement
is the degree to which random errors are minimized.
What are some of the reasons why surfaces are important? - CORRECT ANSWER -
Aesthetics
-safety
-friction and wear
-effect of surface of mechanical and physical properties
-mating of components in assembly
-electrical contacts
Define nominal surface. - CORRECT ANSWER The nominal surface is the ideal part
surface represented on an engineering drawing. It is assumed perfectly smooth; perfectly flat
if referring to a planar surface; perfectly round if referring to a round surface, etc.
Define surface texture. - CORRECT ANSWER Surface texture is the random and
repetitive deviations from the nominal surface, including roughness, waviness, lay, and flaws.
How is surface texture distinguished from surface integrity? - CORRECT
ANSWER Surface texture refers only to the surface geometry; surface integrity
includes not only surface but the subsurface layer beneath the surface and the changes in it.
Within the scope of surface texture, how is roughness distinguished from waviness? -
CORRECT ANSWER Roughness consists of the finely-spaced deviations from the
QUESTIONS AND CORRECT ANSWERS
How does solidification of alloys differ from solidification of pure metals? - CORRECT
ANSWER Solidification of pure metals takes place at constant temperature while
solidification of alloys takes place over a range of temperatures.
What does heat of fusion mean in casting? - CORRECT ANSWER In casting, the heat
of fusion is the amount of energy that is involved in the material's phase change from liquid
to solid. In other words, heat of fusion is the value of the amount of heat the metal dissipates
when changing phase from liquid to solid.
Identify the three sources of contraction in a metal casting after pouring - CORRECT
ANSWER 1.) Liquid shrinkage: contraction of the metal after pouring and/or when hot
liquid nears freezing temperature
2.) Solidification shrinkage: shrinkage during phase transformation from liquid to solid
3.) Solid shrinkage: the shrinkage when the casting is cooled from freezing temp to ambient
temperature
Indicate the mathematical equation for the flow curve. - CORRECT ANSWER The
mathematical equation for the flow curve is, σ= Kε^n; where σ=true stress, K=strength
coefficient, ε=true strain, and n=strain hardening exponent.
How does increasing temperature affect the parameters in the flow curve equation? -
CORRECT ANSWER Increasing the temperature decreases K, the strength coefficient
and n, the strain hardening factor.
Indicate some of the advantages of cold working relative to warm and hot working. -
CORRECT ANSWER Greater accuracy, better surface finish, high strength and
hardness, grain flow => desirable directional properties, no heating of work required
What is a tolerance? - CORRECT ANSWER A tolerance is defined as the total amount
by which a specified dimension is permitted to vary.
, What is the difference between a bilateral tolerance and a unilateral tolerance? - CORRECT
ANSWER A bilateral tolerance allows variation in both positive and negative
directions from the nominal dimension, whereas a unilateral tolerance allows the variation
from the nominal dimension to be either positive or negative, but not both.
What is accuracy in measurement? - CORRECT ANSWER Accuracy is the degree to
which the measured value agrees with the true value of the quantity of interest. It is a
measurement procedure that is absent of systematic errors.
What is precision in measurement? - CORRECT ANSWER Precision in measurement
is the degree to which random errors are minimized.
What are some of the reasons why surfaces are important? - CORRECT ANSWER -
Aesthetics
-safety
-friction and wear
-effect of surface of mechanical and physical properties
-mating of components in assembly
-electrical contacts
Define nominal surface. - CORRECT ANSWER The nominal surface is the ideal part
surface represented on an engineering drawing. It is assumed perfectly smooth; perfectly flat
if referring to a planar surface; perfectly round if referring to a round surface, etc.
Define surface texture. - CORRECT ANSWER Surface texture is the random and
repetitive deviations from the nominal surface, including roughness, waviness, lay, and flaws.
How is surface texture distinguished from surface integrity? - CORRECT
ANSWER Surface texture refers only to the surface geometry; surface integrity
includes not only surface but the subsurface layer beneath the surface and the changes in it.
Within the scope of surface texture, how is roughness distinguished from waviness? -
CORRECT ANSWER Roughness consists of the finely-spaced deviations from the
