Which element is commonly found in stainless steel?

Which element is commonly found in stainless steel?

• A. Chromium
• B. Iron
• C. Copper
• D. Zinc

Answer: (A)

Stainless steel owes its corrosion resistance to chromium. When chromium is present in the alloy (typically around 10.5% or more), it forms a thin, adherent chromium oxide film on the surface. This passive layer acts as a barrier to water, oxygen, and ions, preventing rust. The film is self-healing: if the surface is scratched, its formation continues to re-passivate the metal. Iron alone would rust in such environments, so the chromium-containing oxide film is what makes steel “stainless.” Copper and zinc aren’t the defining elements for this property—zinc is mainly used to galvanize steel, and copper appears only in some specialized grades. Thus, chromium is the element commonly found in stainless steel.

Stainless steel owes its corrosion resistance to chromium. When chromium is present in the alloy (typically around 10.5% or more), it forms a thin, adherent chromium oxide film on the surface. This passive layer acts as a barrier to water, oxygen, and ions, preventing rust. The film is self-healing: if the surface is scratched, its formation continues to re-passivate the metal. Iron alone would rust in such environments, so the chromium-containing oxide film is what makes steel “stainless.” Copper and zinc aren’t the defining elements for this property—zinc is mainly used to galvanize steel, and copper appears only in some specialized grades. Thus, chromium is the element commonly found in stainless steel.