Which property describes the hardenability of a metal alloy, its ability to be hardened by heat treatment?

Which property describes the hardenability of a metal alloy, its ability to be hardened by heat treatment?

• A. Hardenability
• B. Hardness
• C. Elasticity
• D. Conductivity

Answer: (A)

Hardenability describes the metal’s ability to form a hardened structure throughout its volume during heat treatment. It is about how deeply and uniformly hardness can develop after quenching, not just how hard the surface is at a single moment. This property depends on alloy chemistry and transformation kinetics: certain alloying elements slow down the transformation to softer phases and enable martensite to form deeper inside the piece, while others don’t promote deep hardening as effectively. That’s why a steel with high hardenability can become martensitic deeper into a long bar after the same quench, whereas a low-hardnessability steel may only harden near the surface. The concept is often quantified by tests like the Jominy end-quench test, which links cooling rate to the resulting hardness profile. By contrast, hardness is the measure of resistance to indentation at a given condition, elasticity is the ability to deform elastically and return to the original shape, and conductivity refers to the ability to conduct heat or electricity.

Hardenability describes the metal’s ability to form a hardened structure throughout its volume during heat treatment. It is about how deeply and uniformly hardness can develop after quenching, not just how hard the surface is at a single moment. This property depends on alloy chemistry and transformation kinetics: certain alloying elements slow down the transformation to softer phases and enable martensite to form deeper inside the piece, while others don’t promote deep hardening as effectively. That’s why a steel with high hardenability can become martensitic deeper into a long bar after the same quench, whereas a low-hardnessability steel may only harden near the surface. The concept is often quantified by tests like the Jominy end-quench test, which links cooling rate to the resulting hardness profile.

By contrast, hardness is the measure of resistance to indentation at a given condition, elasticity is the ability to deform elastically and return to the original shape, and conductivity refers to the ability to conduct heat or electricity.