Which statement about chromium's role in steel is accurate?

• A. Chromium reduces hardness of steel.
• B. Chromium has no effect on steel.
• C. Chromium provides hardness and toughness to steel.
• D. Chromium makes steel magnetic.

Answer: (C)

Chromium in steel acts to increase hardenability and form hard chromium carbides, which boosts hardness and wear resistance, while also improving the microstructure so toughness can be enhanced in many alloy systems. That combination—hardness and the ability to resist cracking under stress—fits the description of providing hardness and toughness to steel. It certainly has an effect on steel, rather than none, and it isn’t a simple feature like magnetism that can be stated as a universal result—the magnetic behavior depends on the steel’s phase and composition. So the statement that chromium provides hardness and toughness best captures its typical and useful role in steel.