Normalizing is a process of heat treating iron-base metals only.

• A. Aluminum alloys only
• B. Iron-base metals only
• C. Copper alloys only
• D. All metals

Answer: (B)

Normalizing is a heat treatment used to refine the grain structure and relieve internal stresses in iron-base alloys. It works by heating steel or cast iron above the critical (austenite) temperature and then allowing it to cool in air, which produces a finer, more uniform microstructure and improved toughness. This transformation relies on the iron–carbon phase relationships that govern steels and cast irons, something non-ferrous metals don’t exhibit in the same way. Aluminum alloys, copper alloys, and other metals use different heat treatment schemes (like solution treatment and aging for aluminum, annealing or precipitation hardening for copper) rather than normalization. Because the process depends on austenite formation in iron-rich systems, it applies to iron-base metals only.