This set of Basic Foundry Questions and Answers focuses on “Centrifuging Processes”.
1. In centrifugal castings, the molten metal is introduced into a ___________ mould.
a) Rotating
b) Static
c) Swinging
d) Heating
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Explanation: The essential feature of centrifugal casting is the introduction of liquid metal into a rotating mould. The force responsible for it is the centrifugal force which plays a major role in shaping and feeding of the casting.
2. True centrifugal castings are __________ in shape.
a) Straight
b) Square
c) Round
d) Rectangular
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Explanation: The true centrifugal castings are straight and have uniform inner diameter is produced by spinning the mold about its own axis. It is rotated either vertically or horizontally as needed to do it.
3. The metal is poured in the inner surface of the mold cavity.
a) True
b) False
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Explanation: A cylindrical mold is utilized in the true centrifugal casting and is made to rotate on its own axis at such a speed that the metal is poured is thrown to the outer surface of the mould cavity. The metal solidifies to form a hollow cylinder.
4. In the De Lavaud casting process, the coolant used is ___________
a) Water
b) Resin
c) Aerated water
d) Inert gases
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Explanation: The De Lavaud process makes use of the metal moulds. The machine contains an accurately machined metal mould (die), entirely surrounded by the cooling water to keep it cool and to increase the production.
5. The De Lavaud machine is highly locomotive.
a) True
b) False
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Explanation: The De Lavaud machine makes use of the metal moulds. This machine is mounted on wheels and it can be moved lengthwise. This is placed on a slightly inclined track to increase flexibility.
6. True centrifugal castings can be prepared in ___________ moulds.
a) Metal
b) Sand
c) Metal and sand
d) Sand and chemical
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Explanation: Metal moulds prove to be economical when larger quantities of castings are required to be produced. The true centrifugal castings may be produced in metal or sand lined moulds, depending largely upon the quantity desired.
7. The _____________ parts are cast in centrifuge castings.
a) Symmetrical
b) Asymmetrical
c) Identical
d) Non-Identical
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Explanation: Parts not symmetrical about any axis of rotation may be cast in the group of moulds arranged in a circle to balance each other. The axis of mold and that of rotation does not coincide with wach other. The set up is revolved around centre to induce pressure on the metal moulds.
8. There are a lot of limitations on the castings produced by the centrifuge castings.
a) True
b) False
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Explanation: In centrifuge castings, the shape of the castings imposes no special limitations in this process and an almost unlimited variety of smaller shapes can be cast using this process.
9. _________ molding is used to produce valve bodies in centrifuge casting.
a) Stack
b) Straight
c) Hand
d) Machine
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Explanation: In centrifuge castings, when the castings in multiple layers one above the other are produced in one mould, the method is called stack molding. It is used for producing valves bodies, plugs, yokes etc.
10. High spinning is needed in semi-centrifuge casting.
a) True
b) False
View Answer
Explanation: Spinning speeds in the semi centrifuge casting need not be as high as those used for true centrifuge castings. A linear speed of the order of 180-200 rpm at the outside edge of the casting is generally recommended.
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