What material symbol is frequently used in drawings to represent all metals?

• A. Cast iron
• B. Aluminum
• C. Steel
• D. Copper

Answer: (A)

In drawings, a single metal symbol serves as a quick shorthand for the material family. Cast iron has historically been used as that generic metal symbol because it was the most common metal in many early parts, so the symbol became a convenient stand-in for metal in general. When you see this symbol, it signals that the part is made of metal, with the exact material typically specified elsewhere in notes or a bill of materials. If a particular metal is required, you’ll see aluminum, steel, copper, or another specific material named explicitly rather than relying on the generic metal symbol.