Mixing coal dust with moulding sand results in
A.blackening of the mould
B.strong mould
C.good air venting
D.none of the above
Category: Foundry Technology Mcqs
Hot spots are generally found in castings
A.having abrupt variation in section
B.with uniform cross-section
C.symmetrical about two axes
D.small in weight but large in volume
Flux used in cupola while melting cast iron is
A.lime stone
B.coke slurry
C.molasses
D.any of the above
Which of the following defect may occur due to improper design of gating system?
A.Cold shuts
B.Rough surfaces
C.Misruns
D.any of the above
On drying, wood
A.expands
B.shrinks
C.changes colour
If an old casting is to be used as a pattern, to account for various allowances.
A.casting is shaken while withdrawing from mould
B.the surfaces are lagged with thin strips of wood or leater
C.the castings are cleaned and made smooth
D.to provide draw screws, holes can be drilled and tapped in the castings
Alloy containing 70% nickel and 30% copper is known as
A.hastalloy
B.monel metal
C.N-c alloy
D.permalloy
Moisture content of the moulding sand is commonly
A.1% – 4%
B.2% – 8%
C.5% – 15%
Generally for the melting of cast iron, electric furnaces are not used because
A.cast iron is in the form of broken pieces
B.cast iron requires higher temperature for heating
C.the rate of heating required for melting cast iron connot be provided by electric furnaces
D.It is expensive to use electricity for melting of cast iron
Contraction of metal starts at the end of
A.liquid stage
B.mushy stage
C.plastic stage
D.solid stage
