Q164
For a steel containing 0.8% carbon
A.
There is no critical point
B.
There is only one critical point
AnswerC.
There are two critical points
D.
There can be any number of critical points
Answer: Option B
Solution
Answer: Option B
Solution:
When steels with exactly 0.8% carbon (known as a eutectoid steel), are cooled, the austenitic phase (FCC) of the mixture attempts to revert to the ferrite phase (BCC).There is only one critical point in eutectoid steel which contains 0.8% carbon.