Question 17: Which of the following is the correct order of rates for air, water, oil, and furnace?
a) Air, water, oil, furnace
b) Water, oil, air, furnace
c) Water, oil, furnace, air
d) Oil, water, furnace, air
e) Air, furnace, oil, water
Question 18: Which of these microstructure arrangements is going from high to low strengths?
a) Martensite, tempered martensite, pearlite, spheroidite, ferrite
b) Tempered martensite, spheroidite, martensite, pearlite, ferrite
c) Martensite, pearlite, tempered martensite, spheroidite, ferrite
d) Martensite, pearlite, spheroidite, tempered martensite, ferrite
e) Martensite, tempered martensite, spheroidite, pearlite, ferrite
Question 19: What is the main difference between tempered martensite and spheroidite?
a) The type of phases present
b) The volume fraction of cementite particles
c) The shape of cementite particles (plate-like vs. sphere-like)
d) The size of the cementite particles
e) The composition of the cementite particles
Question 20: What is the main reason for performing a Jominy End-Quench test?
a) To determine the hardness of the material
b) To determine the hardenability of the material
c) To form a fully martensitic sample
d) To form a sample with many types of microstructures
e) To determine the effect of heat treatment on a sample's hardness
Question 21: Why is it more difficult to have a fully martensitic sample when the sample is thick?
a) Because the critical cooling rate to form martensite cannot be reached in the middle of the sample
b) Because in thick samples, the martensitic transformation does not have time to cover the entire volume of the sample
c) Because in thick samples, there are more chances for elements to segregate, which in turn will affect the hardenability of the sample
d) Because the volume expansion of martensite prevents it from forming in the bulk of thick samples
e) Because thick samples have larger grains which prevent the formation of the martensitic phase