Materials / Compare
Aluminum vs. Steel AISI 1045
Compare Aluminum vs. Steel AISI 1045 strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 276MPasourcetypical, 0.2% offset, .500 in dia specimen | 531MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 310MPasourcetypical | 627MPasourceproducer-stated, cold drawn |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | 12%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 68.3GPasourcetypical | 210GPasourcetypical3.07x stiffer |
| Density | 2,700kg/m³sourcenominal | 7,800kg/m³sourcetypical |
| Strength to weight | 102kN·m/kg1.5x higher | 68.1kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg | 26.9MN·m/kg6% higher |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.3sourcetypical |
| Shear modulus | 25.7GPa | 80.8GPa3.15x stiffer in shear |
| Bulk modulus | 67GPa | 175GPa |
| Speed of sound | 5,030m/s | 5,189m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 40–45W/m·Ksourcetypical range, ambient |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 12µm/m·Ksourcetypical, mean 20-300 °C |
| 100 mm part over a 50 °C swing | 118µm growth | 60µm growth1.97x less |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 460–480J/kg·Ksourcetypical range, 50/100 °C |
| Heats up and cools (diffusivity) | 69mm²/s5.95x faster | 11.6mm²/s |
| Thermal shock resistance | 19,159W/m3.06x more resistant | 6,269W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | AISI 1045 cold drawn bar (Niagara LaSalle) for mechanical; Ovako C45 (lists 'SAE 1045' as a similar designation) for physical constants |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is Aluminum stronger than Steel AISI 1045?
Steel AISI 1045 is stronger: its yield strength is 531 MPa against 276 MPa for Aluminum (1.92x).
Which is lighter, Aluminum or Steel AISI 1045?
Aluminum is lighter: 2,700 kg/m³ against 7,800 kg/m³ for Steel AISI 1045.
Which is stiffer, Aluminum or Steel AISI 1045?
Steel AISI 1045 is stiffer: Young's modulus 210 GPa against 68.3 GPa for Aluminum, so the same part in Steel AISI 1045 deflects less under the same load.
Which is lighter for the same job, Aluminum or Steel AISI 1045?
For the same stiffness or strength: Aluminum is lighter for a stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Steel AISI 1045 is lighter for a stiff rod or tie (tension).
| Part that must be | Aluminum | Steel AISI 1045 |
|---|---|---|
| Stiff rod or tie (tension) | 6% heavier | lighter |
| Stiff beam (bending) | lighter | 1.65x heavier |
| Stiff panel or plate | lighter | 1.99x heavier |
| Strong rod or tie | lighter | 1.5x heavier |
| Strong beam | lighter | 1.87x heavier |
| Strong panel or plate | lighter | 2.08x heavier |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, Aluminum or Steel AISI 1045?
Aluminum conducts heat better: 167 W/m·K against 42.5 W/m·K for Steel AISI 1045.
Which expands less with temperature?
Steel AISI 1045 expands less: 12 µm/m·K against 23.6 µm/m·K for Aluminum.