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Density of Iron and Iron Alloys

The density of pure iron at room temperature is 7.874 g/cm³ (approximately 491.5 lb/ft³, 0.2845 lb/in³). The chart below lists representative densities for common iron alloys. Values can vary with composition, graphite morphology (for cast irons), porosity, and processing.

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Grams per cubic centimeter
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Constants: 1 g/cm³ = 0.036127292 lb/in³ = 62.4279606 lb/ft³ = 1000 kg/m³.

Density of Iron and Iron Alloys at Room Temperature
Material Density (g/cm³) Density (lb/in³)
Pure iron 7.874 0.2845
Ingot iron 7.866 0.2842
Wrought iron 7.70 0.278
Gray cast iron 7.15 Note-1 0.258 Note-1
Malleable iron 7.27 Note-2 0.262 Note-2
Ductile (nodular) iron 7.15 0.258
High-nickel iron (Ni-Resist) 7.50 0.271
High-chromium white iron 7.40 0.267

Note-1: Gray cast iron typically ranges 6.95–7.35 g/cm³ (0.251–0.265 lb/in³).

Note-2: Malleable iron typically ranges 7.20–7.34 g/cm³ (0.260–0.265 lb/in³).

Physical Properties of Iron

  • Appearance: Silvery-white to gray metal; ductile and malleable.
  • Melting point: 1538 °C.
  • Magnetism: One of the three naturally ferromagnetic elements at room temperature (with nickel and cobalt).
  • Chemical behavior: Reacts with oxygen and moisture to form iron(III) oxide, Fe2O3 (“rust”). Rusting is a chemical change.

FAQs

How are lb/in³ values obtained?
Multiply g/cm³ by 0.036127292 to convert to lb/in³.
Why do cast irons show wider density ranges?
Graphite morphology, alloying elements, and porosity influence the final density of cast irons.

Reference