Shrinkage allowance on pattern is provided to compensate for shrinkage...
Since metal shrinks on solidification and contracts further on cooling to room temperature, linear dimensions of patterns are increased in respect of those of the finished casting to be obtained. This is called the “shrinkage allowance”. So, the temperature of solid phase drops from freezing to room temperature.
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Shrinkage allowance on pattern is provided to compensate for shrinkage...
Explanation:
Shrinkage allowance is an important factor in pattern making. It is provided to compensate for the shrinkage that occurs during the cooling and solidification of the metal in the casting process. The shrinkage allowance is added to the pattern dimensions to ensure that the final cast part has the desired size and shape.
The shrinkage allowance is based on the type of metal being cast and the temperature changes that occur during the casting process. The correct answer is option C because the shrinkage allowance is provided to compensate for the shrinkage that occurs when the temperature of the solid phase drops from freezing to room temperature.
The following are the temperature changes that occur during the casting process and how they affect the shrinkage allowance:
1. Pouring Temperature: The temperature of liquid metal when it is poured into the mold.
2. Freezing Temperature: The temperature at which the metal begins to solidify.
3. Solidification: The process by which the metal changes from a liquid to a solid state.
4. Room Temperature: The temperature of the environment in which the casting is allowed to cool and solidify.
The shrinkage allowance is based on the difference in temperature between the freezing temperature and the room temperature. As the metal cools and solidifies, it shrinks in size. The amount of shrinkage depends on the type of metal being cast and the temperature changes that occur during the casting process.
Conclusion:
In conclusion, the correct answer to the question is C. The shrinkage allowance is provided to compensate for the shrinkage that occurs when the temperature of the solid phase drops from freezing to room temperature. This is an important factor in pattern making and ensures that the final cast part has the desired size and shape.
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