How does heat treatment on metal prevent rusting?

Heat treatment can enhance the corrosion resistance of metals by altering their microstructure and improving mechanical properties. Processes like quenching and tempering create a hard, stable surface that reduces the likelihood of rust formation. Additionally, heat treatment can relieve internal stresses and create a protective oxide layer, further preventing moisture penetration and rust. However, it's important to note that while heat treatment can improve resistance, it doesn't eliminate the need for protective coatings or maintenance in corrosive environments.