🔍 Key Concepts

• Annealing as a metal heat-treatment process • How copper behaves when heated and softened • Difference between hardening and softening metals

💭 Think About

• Think about what the purpose of annealing is: do you want the copper gasket to become harder or softer and more ductile? • Which cooling method usually goes with hardening (quenching for steels) versus softening (annealing) of metals? • Consider which options would add unwanted elements or surface changes to copper, and which would simply change its internal structure.

✅ Before You Answer

• Be clear on the definition of annealing compared with quenching and tempering • Recall whether rapid cooling usually makes a metal softer or harder • Check which methods (water, oil, carbonizing) are commonly associated with steel, not copper