Materials / Compare
Iron vs. Steel AISI 1018
Compare Iron 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 | 186MPasourcetypical (0.2% YS), hot rolled + SRA/recrystallization anneal | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 290MPasourcetypical, SRA/recrystallization anneal | 441MPasourceproducer-stated, cold drawn |
| Elongation at break | 38%sourcetypical, gauge 4D0 | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 207GPasourcetypical, after SRA/recrystallization anneal | 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 | 7,860kg/m³sourcetypical | 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 | 23.7kN·m/kg | 47.3kN·m/kg2x higher |
| Stiffness to weight | 26.3MN·m/kg4% higher | 25.4MN·m/kg |
| Poisson's ratio | 0.282sourceNIST critically evaluated best value (polycrystalline iron) | 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 | 80.7GPa7% stiffer in shear | 75.7GPa |
| Bulk modulus | 158GPa | 185GPa |
| Speed of sound | 5,132m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 73.2W/m·Ksourcetypical at 20 °C | 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 | 13.7µm/m·Ksourcemean, 20-399 °C | 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 | 68.5µm growth | 60µm growth14% less |
| Specific heat | 450J/kg·Ksourcetypical | 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) | 20.7mm²/s1.52x faster | 13.6mm²/s |
| Thermal shock resistance | 3,447W/m | 5,473W/m1.59x more resistant |
| Melting point | 1,532°Csourcetypical | not sourced |
| Values for | Cleveland-Cliffs / AK Steel ARMCO Pure Iron Product Data Bulletin (07/2022): Table 1 typical physical properties, Table 2 typical mechanical properties after SRA/recrystallization anneal. | 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 Iron stronger than Steel AISI 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 186 MPa for Iron (2x).
Which is lighter, Iron or Steel AISI 1018?
Iron is lighter: 7,860 kg/m³ against 7,861 kg/m³ for Steel AISI 1018.
Which is stiffer, Iron or Steel AISI 1018?
Iron is stiffer: Young's modulus 207 GPa against 200 GPa for Steel AISI 1018, so the same part in Iron deflects less under the same load.
Which is lighter for the same job, Iron or Steel AISI 1018?
For the same stiffness or strength: Iron is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Steel AISI 1018 is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Iron | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 4% heavier |
| Stiff beam (bending) | lighter | 2% heavier |
| Stiff panel or plate | lighter | 1% heavier |
| Strong rod or tie | 2x heavier | lighter |
| Strong beam | 1.59x heavier | lighter |
| Strong panel or plate | 41% 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 conducts heat better, Iron or Steel AISI 1018?
Iron conducts heat better: 73.2 W/m·K against 51.9 W/m·K for Steel AISI 1018.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 13.7 µm/m·K for Iron.