Density of Aluminium Alloy 6061
| Value | 2700 kg/m³ |
| Status | Measured: ± 20 kg/m³ (0.0074 relative) |
| Source | ASM Handbook, Vol. 2: Properties of Nonferrous Alloys |
| Categories | Material PropertiesEngineering & Trademechanics |
| kilogram per cubic meter | 2,700 kg/m³ |
| gram per cubic centimeter | 2.7 g/cm³ |
| gram per milliliter | 2.7 g/mL |
| kilogram per liter | 2.7 kg/L |
| pound per cubic foot | 168.55549 lb/ft³ |
| pound per US gallon | 22.532592 lb/gal |
Learning zone
Pure aluminium is 2698 kg/m³ and the common wrought alloys sit within a percent of it: 6061 at 2700, 5052 at 2680, 7075 at 2810 because of the zinc. The number every designer actually uses is the ratio — aluminium is roughly one third the weight of steel, so a section of identical geometry weighs a third as much. That is the whole argument for aluminium ladders, truck bodies and heat sinks.
The trap is finishing the sentence there. Aluminium's stiffness is also about one third of steel's (69 GPa against 200 GPa), so an identical section is three times as flexible. Equal-weight aluminium members have to be made deeper or thicker to match stiffness, which is why aluminium structures look chunky. Weight advantage is real; stiffness advantage is not, and deflection rather than strength usually governs the redesign.