Castings and cold-headed steel balls undergo what specific heat treatment process____________________?
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Answer: B. Normalising
Explanation
Normalizing refines coarse grain structures and produces a uniform microstructure. Castings and cold-worked components often possess uneven internal grain sizes. Heating above the critical temperature and air cooling relieves stresses and normalizes grain size. Normalizing involves heating steel above its upper critical temperature followed by air cooling. This process produces a harder and stronger steel than full annealing processes. Cold-headed components develop high internal stresses that are effectively relieved here.
Forged and cast steel parts undergo normalizing to prepare them for final machining. Automotive components require normalized structures to ensure consistent mechanical performance. Structural steel shapes are often normalized to improve toughness and ductility. Tempering relieves stresses in hardened steel but does not refine coarse as-cast grain structures. Annealing involves slow furnace cooling, which results in softer structures than normalizing. None of these is incorrect because normalizing is the correct heat treatment process.
- Subject
- Engineering
- Category
- Chemical Engineering
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- —
- Difficulty
- medium
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