The essential constituent of a hardened steel is______.

A)
pearlite
B)
austenite
C)
troostite
D)
martensite

Correct Answer : Option (D) :   martensite

Recently Updated in Engineering Materials Questions
Babbit metal contains
A)
92% tin, 6% copper and 2% antimony
B)
88% tin, 4% copper and 8% antimony
C)
66% tin, 30% copper and 4% antimony
D)
50% tin and 50% antimony

Correct Answer :   88% tin, 4% copper and 8% antimony

What is the result of full annealing of hypoeutectoid steels?
A)
Bainite
B)
Silicon
C)
Cementite
D)
Coarse pearlite

Correct Answer :   Coarse pearlite

Explanation : Hypoeutectoid steels are heated above the A3 line and then cooled in the furnace. Then it removed from the furnace and then cooled at room temperature. This results in coarse pearlite with excess ferrite.

A fine grained steel
A)
is less tough and has a less tendency to distort during heat treatment
B)
is less tough and has a greater tendency to distort during heat treatment
C)
is more ductile and has a less tendency to distort during heat treatment
D)
is more ductile and has a greater tendency to distort during heat treatment

Correct Answer :   is more ductile and has a less tendency to distort during heat treatment

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