Which property of moulding sand ensures that the sand retains its shape and hardness at high temperatures when the molten metal is poured into the mould?
DSSSB - 2023,
Answer: B
Refractoriness is the property of moulding sand that makes it retain its shape and strength at the high temperature of molten metal without melting or fusing. Adhesiveness is the ability to stick to other materials such as the moulding box, permeability is the ability to let gases escape, and cohesiveness is the ability of sand grains to stick together. So refractoriness is the property in question.
Silica sand is widely used because it fuses at about 1700 degrees Celsius, well above the pouring temperature of cast iron.
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