What is the term for steel with carbon content less than 0.8%?

What is the term for steel with carbon content less than 0.8%?

• A. Hyper-eutectoid steel
• B. Eutectoid steel
• C. Hypoeutectoid steel
• D. Ferritic steel

Answer: (C)

The key idea is that steel is classified by carbon content relative to the eutectoid composition, which is about 0.77–0.80% carbon. When the carbon content is less than that, the steel is called hypoeutectoid. Its microstructure consists mainly of ferrite with some pearlite (proeutectoid ferrite plus pearlite), and its properties reflect the dominance of ferrite. Since the question specifies carbon content below 0.8%, the correct term is hypoeutectoid steel. Hyper-eutectoid would mean more than the eutectoid carbon, eutectoid steel would be around the eutectoid composition itself, and ferritic steel describes a structure type rather than a strict carbon-content category.

The key idea is that steel is classified by carbon content relative to the eutectoid composition, which is about 0.77–0.80% carbon. When the carbon content is less than that, the steel is called hypoeutectoid. Its microstructure consists mainly of ferrite with some pearlite (proeutectoid ferrite plus pearlite), and its properties reflect the dominance of ferrite. Since the question specifies carbon content below 0.8%, the correct term is hypoeutectoid steel. Hyper-eutectoid would mean more than the eutectoid carbon, eutectoid steel would be around the eutectoid composition itself, and ferritic steel describes a structure type rather than a strict carbon-content category.