Craft · 6 pages · 12 min
Why annealing softens it again
Heating work-hardened copper grows new grains and erases the hardness cold work put in.
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From the opening
Annealing softens work-hardened copper by heating it until new grains grow and replace the strained ones, clearing out most of the tangled dislocations. The copper can be cooled in water afterward and still be soft, because it does not harden in a quench the way carbon steel does. The opening covers new grains replace strained crystals, dull red is the working heat, and a water quench leaves copper soft.
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Inside
- New grains replace strained crystals
- Dull red is the working heat
- A water quench leaves copper soft
- Too much heat coarsens the grains
- Where the idea stops applying
- A distinction worth keeping
Sources
- Recrystallization annealing of copper
- Quench response unlike carbon steel