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51.

The properties of cast iron are regulated by

A.	The composition of raw material	B.	Heating temperature
C.	Heat treatment	D.	Percentage of carbon present
E.	Control of amount, type, size and distribution of various carbon formations

52.

The consitituent which has a powerful softening effect on cast iron and its presence in cast iron reduces the ability of the iron to retain carbon in chemical combination, is

A.	Silicon	B.	Aluminium
C.	Carbon	D.	Sulphur
E.	Chromium

53.

Tensile strength of common varieties of cast iron is in the range

A.	40 - 50 M Pa	B.	50 - 80 M Pa
C.	140 - 500 M Pa	D.	500 - 650 M Pa
E.	650 - 1000 M Pa

54.

The elastic limit of cast iron is

A.	Low	B.	High
C.	Same as that of mild steel	D.	Low compression strength
E.	Close to ultimate breaking strength

55.

Grey iron

A.	Has low ductility	B.	Breaks with appreciable distortion
C.	Has brittleness	D.	Low compression strength
E.	None of the above

56.

In cast irons

A.	Impact strength is high	B.	With static loading the strength in tension is higher than that in compression
C.	With static loading the strength in tension is lower than that in compression	D.	(A) and (B) above
E.	(A) and (C) above

57.

Cast irons are generally specified by

A.	Carbon percentage	B.	Iron percentage
C.	Hardness	D.	Process of manufacture
E.	Tensile strength

58.

In carbon steel castings

A.	The percentage of carbon is less than 1.7%	B.	The percentage of carbon is between 1.7% to 2%
C.	The percentage for alloying elements is controlled	D.	(A) and (C) above
E.	(B) and (C) above

59.

Steel castings

A.	Are weldable	B.	Are not weldable
C.	Have poor endurance properties	D.	Can withstand impact
E.	Cannot withstand impact

60.

High ratio of surface to mass tend to

A.	Produce smaller depths of hardening	B.	Produce greater depth of hardening
C.	Produce only chilled surfaces	D.	Produce non-uniformity in hardness on surface
E.	Produce surface defects