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211.

In a specimen of hardened steel, hard and soft spots indicate

A.	Fre carbon	B.	Uneven heating
C.	Non-uniform composition of steel	D.	Presence of pearlite
E.	Presence of cementite

212.

If a medium carbon hardened steel shows pearlite structure it may be concluded that

A.	Steel contains impurities	B.	Steel has been slowly cooled in furnace
C.	Steel has been quenched in oil	D.	Steel has been quenched in water

213.

Which of the following structure is least hard?

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

214.

The unit of diffusion coefficient is

A.	metre second	B.	metre second-1
C.	metre2 second-1	D.	metre-2 second-1

215.

If a sample of steel shows unsymmetrical deformation of a piece in quenching, the probable cause could be

A.	Excessive proportion of alloying elements	B.	Non-uniform heating or cooling
C.	Impure quenching oil	D.	Low temperature during heating
E.	Low specific heat of quenching oil

216.

Ferrite is

A.	Amorphous and brittle	B.	Soft and ductile
C.	Hardenable under rapid cooling	D.	Present in abundance in high carbon steel

217.

Which of the following affects the hardenability of steel?

A.	Austenitic composition	B.	Austenitic grain size
C.	Amount, nature and distribution of undissolved or insoluble particles in austenite	D.	All of the above

218.

The depth of hardening is affected by

A.	Size of specimen	B.	Hardenability of steel
C.	Quenching medium	D.	All of the above

219.

Local hardening of steel can be done by all of the following EXCEPT:

A.	induction hardening	B.	flame hardening
C.	stepped uniform heating	D.	resistance heating

220.

Hardening by carburizing is limited to

A.	0.05 mm	B.	0.1 mm
C.	2 mm	D.	5 mm