Following cold working operations, metallic components are usually subjected to what treatment for stress relief__________________?
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Answer: D. annealing
Explanation
Cold working deforms metal below its recrystallization temperature, leaving high internal residual stresses behind. Annealing heats the cold-worked metal to a specific elevated temperature for stress relief. This thermal treatment allows atoms to rearrange and relieve locked-in internal mechanical stresses effectively. Cold working increases material hardness and strength through extensive dislocation entanglement within the crystal structure. Annealing involves controlled heating followed by slow cooling to restore ductility and relieve internal strain. The stress-relief annealing temperature remains below the critical recrystallization threshold to preserve strength.
Cold-drawn steel rods and stamped sheet metal parts require annealing to prevent post-machining distortion. Unrelieved internal stresses can cause manufactured parts to warp or crack over time during storage. Proper heat treatment ensures dimensional stability and prepares components for subsequent manufacturing steps. Hot working takes place above the recrystallization temperature and does not constitute a stress-relief treatment. Tempering is a specific heat treatment applied primarily to hardened martensitic steels to improve toughness. Normalizing refines grain structure in steels by heating above the upper critical temperature and air cooling.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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