321 Stainless Steel Heat Treatment Processes

AQs:

1. What is the solution annealing temperature for 321? 920-1150°C, followed by water or air quenching.

2. Why is rapid cooling necessary after annealing? To prevent carbide precipitation and maintain corrosion resistance.

3. Can 321 be hardened by heat treatment? No, it is austenitic and cannot be hardened by quenching; only cold working increases strength.

4. Is stress relief treatment needed for 321? Yes, after heavy cold working (≥15% deformation) to reduce residual stresses.

5. What happens if 321 is heated below 920°C? Partial carbide precipitation may occur, reducing corrosion resistance slightly.