Which statement about stainless steel is true?

• A. Stainless steel rusts easily in humid air.
• B. Stainless steel resists corrosion and will not stain other metals when in contact with them.
• C. Stainless steel is softer than lead.
• D. Stainless steel cannot be formed into sheets.

Answer: (B)

Stainless steel’s standout property is its corrosion resistance due to a chromium-rich oxide film that forms on its surface when exposed to oxygen. This passive layer acts like a protective shield, preventing iron from oxidizing and thus stopping rust under typical humid conditions. Because that same film keeps the surface relatively nonreactive, stainless steel usually won’t stain or transfer staining to other metals when they touch it. It’s also a material commonly made into sheets, which is a staple use in sheet metal work.

In contrast, the idea that it rusts easily in humid air goes against how the protective film works, though in very aggressive environments (like with certain chlorides or improper passivation) corrosion can occur. And stainless steel is not softer than lead; in fact it’s much harder and stronger, yet still workable into sheets and other forms.