Engineering :: Foundry Technology

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71.

Graphite is sprinkled on to the surface of green sand moulds to

A.	exclude the burn out effect	B.	improve surface finish
C.	minimize surface finish	D.	reduce the number of blow holes

72.

Which of the following is used to increase refractoriness of sand?

A.	Graphite	B.	Silica flour
C.	Iron free zirconium	D.	all of the above

73.

Which of the following is used as protective admixture in moulding sand for magnesium castings?

A.	Boric acid	B.	Sublimed sulphur
C.	Fluoric additives	D.	Any of the above

74.

Head storage capacity of moulding sand can be increased by adding?

A.	graphite	B.	chromite
C.	magnesium powder	D.	any of the above

75.

Addition of saw dust to moulding sand increases its

A.	gas permeability	B.	refractoriness
C.	cohesiveness	D.	all of the above

76.

Shatter test is a measure of

A.	sand toughness	B.	sand adhesiveness
C.	sand cohesiveness	D.	none of the above

77.

Which of the following is a screen?

A.	Shovel	B.	Riddle
C.	Rearner	D.	Slick

78.

A slick is mainly used for

A.	making openings in mould	B.	providing openings in the mould
C.	repairing and finishing of mould	D.	removing pattern from the mould

79.

Swab is used for

A.	applying water to the mould around the edge of the pattern	B.	shaking pattern to facilitate its with drawl from the mould
C.	repairing and finishing of mould	D.	none of the above

80.

Which of the following facilitates shaking and lifting large pattern from the mould?

A.	Trowel	B.	Swab
C.	Bellows	D.	Ripping plate