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151.

The process of austempering results in the formation of

A.	Carburized structure	B.	Nitride structure
C.	Martensitic structure	D.	Bainite structure
E.	Superhand structure

152.

If steel is slowly cooled in furnace, the structure obtained is

A.	Pearlite	B.	Sorbite
C.	Troosite	D.	Acicular
E.	Martensite

153.

If steel is quenched in water, the structure obtained is

A.	Pearlite	B.	Sorbite
C.	Troosite	D.	Acicular
E.	Martensite

154.

If steel is quenched in oil the structure obtained is

A.	Pearlite	B.	Sorbite
C.	Troosite	D.	Acicular
E.	Martensite

155.

If steel is cooled in still air, the structure obtained is

A.	Pearlite	B.	Sorbite
C.	Troosite	D.	Acicular
E.	Martensite

156.

In case of eutectoid steels which one of the following structures has the maximum hardness?

A.	Pearlite	B.	Sorbite
C.	Troosite	D.	Acicular
E.	Martensite

157.

One of the objects of annealing is

A.	To soften the metal	B.	to improve machinability
C.	To refine grain structure	D.	To refine internal stresses
E.	All above

158.

In normalising steel is heated 40-50 C

A.	Above room temperature	B.	Above the upper transformation range
C.	Above the lower transformation range	D.	Below the upper transformation range
E.	Below the lower transformation range

159.

The process in which steel is heated 20? to 40?C below the lower critical temperature, held there for a prolonged period and then allowed to cool slowly in the furnace is known as

A.	Normalising	B.	Annealing
C.	Spheroidising	D.	Tempering
E.	Austempering

160.

The process of reheating the hardened steel to some temperature below the critical range, followed by any rate of cooling is known as

A.	Tempering	B.	Annealing
C.	Austempering	D.	Normalising
E.	Spheroidising