What does 'H' in an alloy designation stand for?

What does 'H' in an alloy designation stand for?

• A. Non-heat-treated
• B. Heat-treated
• C. Hardened
• D. Highly tempered

Answer: (A)

The letter H in an alloy designation indicates hardness achieved by cold work (strain hardening). This means the metal has been strengthened through plastic deformation at room temperature rather than by heating it. That’s why the option describing it as hardened through cold work is the best fit. Heat-treated corresponds to tempering or aging processes denoted by T, not H. Non-heat-treated is typically labeled differently (often O or F in some systems), and highly tempered isn’t a standard designation. So, the correct idea is that the alloy is hardened by cold working.

The letter H in an alloy designation indicates hardness achieved by cold work (strain hardening). This means the metal has been strengthened through plastic deformation at room temperature rather than by heating it. That’s why the option describing it as hardened through cold work is the best fit. Heat-treated corresponds to tempering or aging processes denoted by T, not H. Non-heat-treated is typically labeled differently (often O or F in some systems), and highly tempered isn’t a standard designation. So, the correct idea is that the alloy is hardened by cold working.