Materials / Compare
Nickel Inconel 718 vs. Stainless 303
Compare Nickel Inconel 718 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 | 1,207MPasourcetypical, 1.0 in. hot-rolled bar, 0.2% offset | 275MPasourceOutokumpu typical (product P = hot rolled plate, transverse) |
| Ultimate tensile strength | 1,389MPasourcetypical, 1.0 in. bar | 585MPasourceOutokumpu typical |
| Elongation at break | 20%sourcetypical, 1.0 in. bar | 35%sourceOutokumpu typical, A5 |
| Young's modulus (stiffness) | 200GPasourcetypical, 21 °C, annealed + aged | 200GPasourceat RT (Table 12) |
| Density | 8,221kg/m³sourcenominal, annealed and aged | 7,900kg/m³sourceat RT |
| Strength to weight | 147kN·m/kg4.22x higher | 34.8kN·m/kg |
| Stiffness to weight | 24.3MN·m/kg | 25.3MN·m/kg4% higher |
| Poisson's ratio | 0.294sourcetypical, 21 °C, annealed + aged | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 77.3GPa | 76.9GPa |
| Bulk modulus | 162GPa | 167GPa |
| Speed of sound | 4,932m/s | 5,032m/s |
| Thermal | ||
| Thermal conductivity | 11.4W/m·Ksourcetypical, 21 °C, annealed + aged (calculated from resistivity per footnote a) | 15W/m·Ksourceat RT |
| Thermal expansion | 13.2µm/m·Ksourcetypical, mean 21-93 °C, annealed + aged | 16µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 66µm growth21% less | 80µm growth |
| Specific heat | 435J/kg·Ksourcetypical, 21 °C | 500J/kg·Ksourceat RT |
| Heats up and cools (diffusivity) | 3.19mm²/s | 3.8mm²/s19% faster |
| Thermal shock resistance | 3,680W/m4.08x more resistant | 902W/m |
| Melting point | 1,260–1,336°Csourcemelting range | not sourced |
| Max service temperature | 704°Csourceupper use temperature stated by producer | 871°Csourcecontinuous, scaling limit |
| Values for | INCONEL alloy 718, standard grade, 1750 °F/1 hr anneal + 1325 °F/8 hr F.C. to 1150 °F aged; Special Metals bulletin SMC-045 typical values | 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 Nickel Inconel 718 stronger than Stainless 303?
Nickel Inconel 718 is stronger: its yield strength is 1,207 MPa against 275 MPa for Stainless 303 (4.39x).
Which is lighter, Nickel Inconel 718 or Stainless 303?
Stainless 303 is lighter: 7,900 kg/m³ against 8,221 kg/m³ for Nickel Inconel 718.
Which is stiffer, Nickel Inconel 718 or Stainless 303?
Nickel Inconel 718 is stiffer: Young's modulus 200 GPa against 200 GPa for Stainless 303, so the same part in Nickel Inconel 718 deflects less under the same load.
Which is lighter for the same job, Nickel Inconel 718 or Stainless 303?
For the same stiffness or strength: Nickel Inconel 718 is lighter for a strong rod or tie, strong beam, strong panel or plate; Stainless 303 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate.
| Part that must be | Nickel Inconel 718 | Stainless 303 |
|---|---|---|
| Stiff rod or tie (tension) | 4% heavier | lighter |
| Stiff beam (bending) | 4% heavier | lighter |
| Stiff panel or plate | 4% heavier | lighter |
| Strong rod or tie | lighter | 4.22x heavier |
| Strong beam | lighter | 2.58x heavier |
| Strong panel or plate | lighter | 2.01x 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, Nickel Inconel 718 or Stainless 303?
Stainless 303 conducts heat better: 15 W/m·K against 11.4 W/m·K for Nickel Inconel 718.
Which expands less with temperature?
Nickel Inconel 718 expands less: 13.2 µm/m·K against 16 µm/m·K for Stainless 303.