Definition
A metal that contains iron as its principal element. Ferrous metals include steel, carbon steel, alloy steel, stainless steel, and cast iron. Most ferrous metals are magnetic and, unless alloyed or treated, are prone to rust and corrosion.
Plain English
A metal that is made mostly of iron. Steel and cast iron are the common examples.
Context Anchor
Seen in aircraft maintenance discussions about materials, corrosion, welding, fasteners, and structural parts.
Derivation
From the Latin ferrum, meaning iron. The chemical symbol for iron, Fe, comes from the same root. So 'ferrous' simply means 'of iron.'
Why Pilots Care
Ferrous metals can introduce corrosion risks and magnetic interference with compasses or instruments if used in the wrong locations on the aircraft.
Intuition Check
Ferrous does not mean “any metal.” It specifically means a metal that contains iron.
Example Sentence 1
The technician used a magnet to quickly check whether the bracket was a ferrous metal before selecting the correct corrosion inhibitor.
Example Sentence 2
Mechanics avoid placing ferrous metal tools near the magnetic compass during preflight checks to prevent deviation errors.