Can you explain the answer of this question below:Shrinkage allowance on pattern is provided to compensate for shrinkage whenA:the temperature of liquid metal drops from pouring to freezing temperatureB:the metal changes from liquid to solid state at freezing temperatureC:the temperature of solid phase drops from freezing to room temperatureD:the temperature of metal drops from pouring to room temperatureThe answer is c.

Question

Answer

Shrinkage allowance on a pattern is provided to compensate for shrinkage when the temperature of the solid phase drops from freezing to room temperature. This is the correct answer because shrinkage occurs during the solidification process of a metal casting.

Explanation:
- Shrinkage refers to the reduction in size or volume of a material as it cools and solidifies. When a metal changes from its liquid state to a solid state, it undergoes a contraction in volume due to the rearrangement of atoms.
- The cooling process starts when the liquid metal is poured into the mold. As the temperature of the metal drops from pouring temperature to the freezing temperature, it begins to solidify. During this phase, the metal undergoes shrinkage due to the rearrangement of its atomic structure.
- However, the solidification process does not stop at the freezing temperature. The metal continues to cool down from the freezing temperature to the room temperature, and further contraction or shrinkage occurs during this phase.
- The shrinkage allowance on the pattern compensates for this additional shrinkage that occurs as the temperature of the solid phase drops from the freezing temperature to the room temperature.
- By providing a slightly larger pattern size, the shrinkage allowance ensures that the final solid cast metal will have the desired dimensions after the cooling and solidification process.
- The amount of shrinkage allowance depends on various factors such as the type of metal being cast, its composition, and the specific casting process used.
- It is important to accurately determine and incorporate the shrinkage allowance in the pattern design to ensure that the final cast part meets the required dimensional specifications.
- Failure to consider the shrinkage allowance can result in undersized castings, which may lead to dimensional inaccuracies and functional issues in the final product.
- Therefore, the shrinkage allowance on the pattern compensates for the shrinkage that occurs as the temperature of the solid phase drops from the freezing temperature to the room temperature, ensuring the desired dimensions of the final cast metal.

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