Materials / Compare
Aluminum vs. Stainless 303
Compare Aluminum vs. Stainless 303 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 | 275MPasourceOutokumpu typical (product P = hot rolled plate, transverse) |
| Ultimate tensile strength | 310MPasourcetypical | 585MPasourceOutokumpu typical |
| Elongation at break | 17%sourcetypical, in 4D, 0.500 in dia specimen | 35%sourceOutokumpu typical, A5 |
| Young's modulus (stiffness) | 68.3GPasourcetypical | 200GPasourceat RT (Table 12) |
| Density | 2,700kg/m³sourcenominal | 7,900kg/m³sourceat RT |
| Strength to weight | 102kN·m/kg2.94x higher | 34.8kN·m/kg |
| Stiffness to weight | 25.3MN·m/kg | 25.3MN·m/kg |
| Poisson's ratio | 0.33sourcetypical (handbook physical constant) | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 25.7GPa | 76.9GPa3x stiffer in shear |
| Bulk modulus | 67GPa | 167GPa |
| Speed of sound | 5,030m/s | 5,032m/s |
| Thermal | ||
| Thermal conductivity | 167W/m·Ksourcetypical, 20 °C | 15W/m·Ksourceat RT |
| Thermal expansion | 23.6µm/m·Ksourcetypical, mean 20-100 °C | 16µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 118µm growth | 80µm growth48% less |
| Specific heat | 896J/kg·Ksourcetypical, at 100 °C | 500J/kg·Ksourceat RT |
| Heats up and cools (diffusivity) | 69mm²/s18.2x faster | 3.8mm²/s |
| Thermal shock resistance | 19,159W/m21.2x more resistant | 902W/m |
| Melting point | 582–652°Csourcesolidus-liquidus | not sourced |
| Max service temperature | not sourced | 871°Csourcecontinuous, scaling limit |
| Values for | 6061-T6/T651, Kaiser Aluminum typical properties (sheet, coil & plate datasheet); Poisson from MIL-HDBK-5J | 1.4305 / UNS S30300, Outokumpu typical values (hot rolled, solution annealed) from 'Steel Grades, Properties and Global Standards'; max service from Carpenter CarTech 303 datasheet |
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 Stainless 303?
Aluminum is stronger: its yield strength is 276 MPa against 275 MPa for Stainless 303 (0%).
Which is lighter, Aluminum or Stainless 303?
Aluminum is lighter: 2,700 kg/m³ against 7,900 kg/m³ for Stainless 303.
Which is stiffer, Aluminum or Stainless 303?
Stainless 303 is stiffer: Young's modulus 200 GPa against 68.3 GPa for Aluminum, so the same part in Stainless 303 deflects less under the same load.
Which is lighter for the same job, Aluminum or Stainless 303?
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.
| Part that must be | Aluminum | Stainless 303 |
|---|---|---|
| Stiff rod or tie (tension) | about equal | about equal |
| Stiff beam (bending) | lighter | 1.71x heavier |
| Stiff panel or plate | lighter | 2.05x heavier |
| Strong rod or tie | lighter | 2.94x heavier |
| Strong beam | lighter | 2.93x heavier |
| Strong panel or plate | lighter | 2.93x 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 Stainless 303?
Aluminum conducts heat better: 167 W/m·K against 15 W/m·K for Stainless 303.
Which expands less with temperature?
Stainless 303 expands less: 16 µm/m·K against 23.6 µm/m·K for Aluminum.