Materials / Compare
Nickel Inconel 718 vs. Steel AISI 1018
Compare Nickel Inconel 718 vs. Steel AISI 1018 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 | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 1,389MPasourcetypical, 1.0 in. bar | 441MPasourceproducer-stated, cold drawn |
| Elongation at break | 20%sourcetypical, 1.0 in. bar | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 200GPasourcetypical, 21 °C, annealed + aged | 200GPasourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Density | 8,221kg/m³sourcenominal, annealed and aged | 7,861kg/m³sourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Strength to weight | 147kN·m/kg3.1x higher | 47.3kN·m/kg |
| Stiffness to weight | 24.3MN·m/kg | 25.4MN·m/kg5% higher |
| Poisson's ratio | 0.294sourcetypical, 21 °C, annealed + aged | 0.32sourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Shear modulus | 77.3GPa2% stiffer in shear | 75.7GPa |
| Bulk modulus | 162GPa | 185GPa |
| Speed of sound | 4,932m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 11.4W/m·Ksourcetypical, 21 °C, annealed + aged (calculated from resistivity per footnote a) | 51.9W/m·Ksourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Thermal expansion | 13.2µm/m·Ksourcetypical, mean 21-93 °C, annealed + aged | 12µm/m·Ksourcebase material: unalloyed carbon steel, Ovako family table (S275JR, 'none alloyed structural steels', C <= 0.21%); mean 20-300 °C |
| 100 mm part over a 50 °C swing | 66µm growth | 60µm growth10% less |
| Specific heat | 435J/kg·Ksourcetypical, 21 °C | 486J/kg·Ksourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Heats up and cools (diffusivity) | 3.19mm²/s | 13.6mm²/s4.26x faster |
| Thermal shock resistance | 3,680W/m | 5,473W/m49% more resistant |
| Melting point | 1,260–1,336°Csourcemelting range | not sourced |
| Max service temperature | 704°Csourceupper use temperature stated by producer | not sourced |
| 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 | AISI 1018 cold drawn bar (Niagara LaSalle, cold-finished bar producer) |
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 Steel AISI 1018?
Nickel Inconel 718 is stronger: its yield strength is 1,207 MPa against 372 MPa for Steel AISI 1018 (3.24x).
Which is lighter, Nickel Inconel 718 or Steel AISI 1018?
Steel AISI 1018 is lighter: 7,861 kg/m³ against 8,221 kg/m³ for Nickel Inconel 718.
Which is stiffer, Nickel Inconel 718 or Steel AISI 1018?
Nickel Inconel 718 is stiffer: Young's modulus 200 GPa against 200 GPa for Steel AISI 1018, 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 Steel AISI 1018?
For the same stiffness or strength: Nickel Inconel 718 is lighter for a strong rod or tie, strong beam, strong panel or plate; Steel AISI 1018 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate.
| Part that must be | Nickel Inconel 718 | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | 5% heavier | lighter |
| Stiff beam (bending) | 5% heavier | lighter |
| Stiff panel or plate | 5% heavier | lighter |
| Strong rod or tie | lighter | 3.1x heavier |
| Strong beam | lighter | 2.1x heavier |
| Strong panel or plate | lighter | 1.72x 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 Steel AISI 1018?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 11.4 W/m·K for Nickel Inconel 718.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 13.2 µm/m·K for Nickel Inconel 718.