exam 3 Flashcards
Of the following steels, the one with the highest maximum hardness is?
a steel with 1 weight percent carbon
true or false. if cooling is too rapid, it is possible to surpress the formation of phases predicted by an equilbrium phase diagram.
true
What has the higher yield strength, an alloy that is cold worked 25% or 35%
35%
Which would have a higher yield strength, an alloy that was cold rolled 25% or hot rolled 25%
cold rolled 25%
true or false. The strength of a precipitation hardened alloy is lower than that of an as-solidefied alloy
false
Why is mertensite ever used in the as-quenched condition?
because it is too brittle
What is the heat -treatment it is given after quenching is called?
Tempering
true or false. The formation of a glass in ceramics is predicted by the phase diagram
false
true or false. The strength of a precipitation hardened alloy is lower than that if an as-solidified alloy.
false
What is the most probable decomposition product from austenite in a very slow cooled steel or cast iron.
pearlite
ture or false. Martensite forms when austenite is cooled very quickly in a steel or cast iron
true
true or false. Martensite does not form by a diffusional process
true
True or false. In general the strength of steel increases as ther carbon concentration decreases
False
What mechanical properties increase during cold working.
Ultamite tensile strength, 0.2% offset yield strength, and hardness
What are the three phases of heat treatment
- solutionize
- quench
- age
What is true for the recovery stage of annealing?
the corrosion resistance increases and the residual stress increases
What alloys are eutectic a and b at room temperature
- 30% and 70%
- 71.9% and 28.1%
- 80% and 20%
What increases the modulus of a metal
neither cold or hot working
What increases the hardness of a metal
cold working
What will close up porosity in a metal
both cold and hot working
What will give residual stress in a metal
both cold and hot working
What will give significant texture in a material
cold working
What will give recovery of electrical conductivity
recovery
What will give reduction in residual stress
recovery
What will give better surface finish
cold working
Which gives the greatest change in mechanical properties
recrystallization
What structure is most likely to form in a steel that is slowly cooled through the eutectoid
pearlite
Which crve represents a faster cooling rate and a higher undercooling
curve a
Which transformation that occurs during cooling through the eutectoid in steel would occur with the highest quench rate
martensite
Which transformation that occurs during cooling through the eutectoid in steel would occur with the highest hardness
martensite
Would a hot worked 30% or cold worked 20% plate have a higher yield strength?
cold worked 20%
Would a hot worked 30% or cold worked 20% plate have a higher ultamite tensile strength?
cold worked 20%
Would a hot worked 30% or cold worked 20% plate have a higher hardness?
Cold worked 20%
Would a hot worked 30% or cold worked 20% plate have a higher tensile modulus?
they would have the same
Would a hot worked 30% or cold worked 20% plate have the best corrosion resistance?
hot worked 30%
What direction would have the highest strength before rolling
they would have the same
