Question

Which of the following properties is typically NOT enhanced by the addition of carbon in steel?

• A. Strength
• B. Ductility
• C. Hardness
• D. Corrosion resistance % Corrosion resistance is also generally not enhanced by C. Ductility is more definitively reduced.

Hint:

Effect of Carbon in Steel. Increasing carbon content generally: Increases Strength, Increases Hardness, Decreases Ductility, Decreases Weldability. Corrosion resistance primarily depends on other alloying elements like Cr, Ni.

Answer 1

The Correct Option is B

Steel is an alloy of iron and carbon.
Adding carbon to iron significantly changes its mechanical properties: - Strength: Increasing carbon content generally increases the yield strength and ultimate tensile strength of steel, primarily through interstitial solid solution strengthening and the formation of hard cementite (Fe\(_3\)C) phases.
(Enhanced).
- Hardness: Increasing carbon content increases the hardness of steel, making it more resistant to scratching and indentation.
(Enhanced).
- Ductility: Ductility, the ability of a material to deform plastically without fracturing (measured by elongation or reduction in area), generally *decreases* as carbon content increases.
Higher carbon steels are stronger and harder but more brittle.
(NOT enhanced; it's reduced).
- Corrosion Resistance: Carbon content itself does not significantly enhance the general corrosion resistance of steel.
Alloying elements like Chromium are added specifically for this purpose (e.
g.
, in stainless steels).
(Generally NOT enhanced by carbon alone).
Between options (2) and (4), the reduction in ductility is a much more direct and pronounced consequence of increasing carbon content in steel compared to its effect on corrosion resistance.
Therefore, ductility is the property most definitively NOT enhanced.