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Annealing versus quenching
Short answer
Annealing uses slow furnace cooling to produce soft, ductile coarse pearlite, relieving stresses and improving machinability. Quenching uses rapid cooling to form hard, brittle martensite, greatly increasing hardness and strength but requiring subsequent tempering to reduce brittleness.
Differentiate between annealing and quenching.
| Point | Annealing | Quenching |
|---|---|---|
| Heating | Above upper critical temperature | Above upper critical temperature |
| Cooling | Very slow (in furnace) | Very rapid (in water, brine or oil) |
| Structure obtained | Coarse pearlite + ferrite | Martensite |
| Hardness | Low, soft | Very high |
| Ductility | High | Very low, brittle |
| Strength | Lower | High |
| Internal stress | Relieved | High stress; cracks and distortion may occur |
| Machinability | Improved | Poor |
| Purpose | Soften, refine grain, relieve stress | Harden for wear resistance |
| Follow-up | Not needed | Must be tempered |
✓ Answer checked by Claude Opus 5.5 (high effort)
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