This set of Casting, Forming and Welding Multiple Choice Questions & Answers (MCQs) focuses on “Properties of Moulding Sand”.
1. Which of the following is not a characteristic property of any moulding sand?
c) Green strength
d) Dry strength
Explanation: Flowability, green strength and dry strength are few of the characteristic properties of moulding sand, but not hardenability.
2. What does a mould having adequate green strength, does not have?
a) Ability to retain its shape
b) Ability not to get distorted
c) Ability not to collapse
d) Ability to retain hardness
Explanation: For a mould to be having an adequate amount of green strength, it must have retaining ability or the ability to get distorted or to collapse. A mould having adequate green strength does not have the ability to retain hardness.
3. Dry sand does not have the strength for what functions?
a) To withstand corrosion forces
b) To withstand pressure of molten metal
c) To be able to retain its shape
d) To be able to retain the hardenability
Explanation: Dry sand has its strength for various purposes like, to withstand pressure of molten metal, to withstand corrosion forces and to be able to retain its shape. But it does not have it for being able to retain the hardenability.
4. Hot strength is seen at what temperature?
a) Above 212°F
b) Above 312°F
c) Above 412°F
d) Above 512°F
Explanation: Hot strength basically is the strength of the sand which is present inside the mould cavity. It is observed that, the hot strength of any material is at 212°F or above it.
5. Which of the following would not happen if hot strength is not enough?
a) The mould may get hardened
b) The mould may get enlarged
c) The mould may get eroded
d) The mould may crack
Explanation: If there is not an adequate amount of hot strength provided, then the mould may get enlarged, the mould may get eroded and the mould may crack, but the mould will not get hardened.
6. Why should the moulding sand be porous?
a) For gases to enter
b) For gases to escape
c) For water to enter
d) For water to escape
Explanation: A moulding sand is the one in which, the sand is known to have holes in it and also it is known for holding some amount of moisture content. A moulding should be having pores and should be permeable, so that the gases have a free path for escaping.
7. Which of the following is not a defect if permeability is not enough?
b) Gas holes
c) Mould blast
d) Surface blows
Explanation: If the permeability or the porosity is less or the permeability is found to be inadequate or the porosity is found to be absent, then brittleness is not the defect it has, but it may have, gas holes or mould blasts or surface blows.
8. In green sand what is the amount of water used?
Explanation: In green sand, the amount of clay that is needed in percentage composition is around 15% to 30%. The amount of water in terms of percentage composition is about 5%.
9. What is the amount of clay needed in green sand?
a) 5% – 10%
b) 5% – 15%
c) 15% – 30%
d) 25% – 40%
Explanation: In green sand, the amount of clay needed in terms of percentage composition is approximately in between 15% to 30% and the amount of water needed in terms of percentage composition is somewhere around 5%.
10. Parting sand is a type of moulding sand.
Explanation: Parting sand is one of the many types of moulding sand which contains silica, sand and burnt sand.
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