Materials / Compare
Stainless 304 vs. Steel AISI 1018
Compare Stainless 304 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 | 241MPasourcetypical, annealed, 70 °F (21 °C) | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 586MPasourcetypical, annealed, 70 °F (21 °C) | 441MPasourceproducer-stated, cold drawn |
| Elongation at break | 55%sourcetypical, annealed, in 2 in. (50.8 mm) | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 193GPasourcetypical, in tension | 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 | 8,030kg/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 | 30kN·m/kg | 47.3kN·m/kg1.58x higher |
| Stiffness to weight | 24MN·m/kg | 25.4MN·m/kg6% higher |
| Poisson's ratio | 0.3sourcedesign value (structural stainless steels) | 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 | 74.2GPa | 75.7GPa2% stiffer in shear |
| Bulk modulus | 161GPa | 185GPa |
| Speed of sound | 4,903m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 16.2W/m·Ksourceat 100 °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 | 16.9µm/m·Ksourcemean, 0–100 °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 | 84.5µm growth | 60µm growth41% less |
| Specific heat | 500J/kg·Ksourcemean, 0–100 °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) | 4.03mm²/s | 13.6mm²/s3.37x faster |
| Thermal shock resistance | 838W/m | 5,473W/m6.53x more resistant |
| Melting point | 1,399–1,454°Csourcemelting range | not sourced |
| Max service temperature | 899°Csourcecontinuous, oxidation (scaling) limit in air | not sourced |
| Values for | Type 304, annealed flat-rolled (Cleveland-Cliffs 304/304L Product Data Bulletin, May 2021); Poisson's ratio from the Nickel Institute/SCI structural stainless design manual | 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 Stainless 304 stronger than Steel AISI 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 241 MPa for Stainless 304 (1.54x).
Which is lighter, Stainless 304 or Steel AISI 1018?
Steel AISI 1018 is lighter: 7,861 kg/m³ against 8,030 kg/m³ for Stainless 304.
Which is stiffer, Stainless 304 or Steel AISI 1018?
Steel AISI 1018 is stiffer: Young's modulus 200 GPa against 193 GPa for Stainless 304, so the same part in Steel AISI 1018 deflects less under the same load.
Which is lighter for the same job, Stainless 304 or Steel AISI 1018?
For the same stiffness or strength: Steel AISI 1018 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 | Stainless 304 | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | 6% heavier | lighter |
| Stiff beam (bending) | 4% heavier | lighter |
| Stiff panel or plate | 3% heavier | lighter |
| Strong rod or tie | 1.58x heavier | lighter |
| Strong beam | 36% heavier | lighter |
| Strong panel or plate | 27% 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, Stainless 304 or Steel AISI 1018?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 16.2 W/m·K for Stainless 304.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 16.9 µm/m·K for Stainless 304.