What is the carbon content range for medium carbon steels?

• A. 0.30-0.45%
• B. 0.05-0.30%
• C. 0.45-0.75%
• D. 0.75-1.50%

Answer: (A)

Medium carbon steels sit between low-carbon and high-carbon steels in carbon content. The added carbon increases strength and hardness and makes heat treatment more effective, while still preserving enough ductility for forming and some weldability. This balance is why medium carbon steels are typically described as roughly 0.30 to about 0.60 percent carbon. The range 0.30–0.45 percent is a common representation of medium carbon steel, giving enough carbon to boost strength and allow meaningful heat treatment (like quenching and tempering) without making the steel overly brittle or difficult to work with. The other ranges describe low-carbon steels (0.05–0.30%) and high-carbon steels (around 0.60% and up), which explains why this middle range is the best fit for the category.