What property is affected by the addition of carbon to mild steel?

What property is affected by the addition of carbon to mild steel?

• A. Hardenability
• B. Ductility
• C. Toughness
• D. Corrosion resistance

Answer: (A)

Hardenability is the property affected by adding carbon to mild steel. Carbon content controls how deeply steel can harden during heat treatment. As carbon increases, more of the steel can transform to martensite when quenched, so hardness develops not just at the surface but deeper into the material. This is why carbon-rich steels can achieve higher hardness after quenching, while very low-carbon mild steel remains relatively soft after the same treatment. Ductility and toughness typically decrease as carbon rises, and corrosion resistance isn’t significantly improved by simply adding carbon, so the main effect tied to carbon content in this context is the hardenability.

Hardenability is the property affected by adding carbon to mild steel. Carbon content controls how deeply steel can harden during heat treatment. As carbon increases, more of the steel can transform to martensite when quenched, so hardness develops not just at the surface but deeper into the material. This is why carbon-rich steels can achieve higher hardness after quenching, while very low-carbon mild steel remains relatively soft after the same treatment. Ductility and toughness typically decrease as carbon rises, and corrosion resistance isn’t significantly improved by simply adding carbon, so the main effect tied to carbon content in this context is the hardenability.