Materials / Compare
Steel AISI 1018 vs. Steel AISI 1045
Compare Steel AISI 1018 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 | 372MPasourceproducer-stated, cold drawn | 531MPasourceproducer-stated, cold drawn43% stronger |
| Ultimate tensile strength | 441MPasourceproducer-stated, cold drawn | 627MPasourceproducer-stated, cold drawn42% stronger |
| Elongation at break | 15%sourcein 2 in (50.8 mm)25% more ductile | 12%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 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) | 210GPasourcetypical |
| Density | 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) | 7,800kg/m³sourcetypical |
| Strength to weight | 47.3kN·m/kg | 68.1kN·m/kg44% higher |
| Stiffness to weight | 25.4MN·m/kg | 26.9MN·m/kg6% higher |
| Poisson's ratio | 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) | 0.3sourcetypical |
| Shear modulus | 75.7GPa | 80.8GPa7% stiffer in shear |
| Bulk modulus | 185GPa | 175GPa |
| Speed of sound | 5,043m/s | 5,189m/s |
| Thermal | ||
| Thermal conductivity | 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) | 40–45W/m·Ksourcetypical range, ambient |
| Thermal expansion | 12µm/m·Ksourcebase material: unalloyed carbon steel, Ovako family table (S275JR, 'none alloyed structural steels', C <= 0.21%); mean 20-300 °C | 12µm/m·Ksourcetypical, mean 20-300 °C |
| 100 mm part over a 50 °C swing | 60µm growth | 60µm growth |
| Specific heat | 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) | 460–480J/kg·Ksourcetypical range, 50/100 °C |
| Heats up and cools (diffusivity) | 13.6mm²/s17% faster | 11.6mm²/s |
| Thermal shock resistance | 5,473W/m | 6,269W/m15% more resistant |
| Values for | AISI 1018 cold drawn bar (Niagara LaSalle, cold-finished bar producer) | 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 Steel AISI 1018 stronger than Steel AISI 1045?
Steel AISI 1045 is stronger: its yield strength is 531 MPa against 372 MPa for Steel AISI 1018 (43%).
Which is lighter, Steel AISI 1018 or Steel AISI 1045?
Steel AISI 1045 is lighter: 7,800 kg/m³ against 7,861 kg/m³ for Steel AISI 1018.
Which is stiffer, Steel AISI 1018 or Steel AISI 1045?
Steel AISI 1045 is stiffer: Young's modulus 210 GPa against 200 GPa for Steel AISI 1018, so the same part in Steel AISI 1045 deflects less under the same load.
Which is lighter for the same job, Steel AISI 1018 or Steel AISI 1045?
For the same stiffness or strength: Steel AISI 1045 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Steel AISI 1018 | Steel AISI 1045 |
|---|---|---|
| Stiff rod or tie (tension) | 6% heavier | lighter |
| Stiff beam (bending) | 3% heavier | lighter |
| Stiff panel or plate | 2% heavier | lighter |
| Strong rod or tie | 44% heavier | lighter |
| Strong beam | 28% heavier | lighter |
| Strong panel or plate | 20% heavier | lighter |
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 is more ductile, Steel AISI 1018 or Steel AISI 1045?
Steel AISI 1018 stretches further before it breaks: 15% elongation at break against 12% for Steel AISI 1045.
Which conducts heat better, Steel AISI 1018 or Steel AISI 1045?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 42.5 W/m·K for Steel AISI 1045.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 12 µm/m·K for Steel AISI 1045.