Materials / Compare
Stainless 303 vs. Steel AISI 1018
Compare Stainless 303 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 | 275MPasourceOutokumpu typical (product P = hot rolled plate, transverse) | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 585MPasourceOutokumpu typical | 441MPasourceproducer-stated, cold drawn |
| Elongation at break | 35%sourceOutokumpu typical, A5 | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 200GPasourceat RT (Table 12) | 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 | 7,900kg/m³sourceat RT | 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 | 34.8kN·m/kg | 47.3kN·m/kg36% higher |
| Stiffness to weight | 25.3MN·m/kg | 25.4MN·m/kg |
| 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 | 76.9GPa2% stiffer in shear | 75.7GPa |
| Bulk modulus | 167GPa | 185GPa |
| Speed of sound | 5,032m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 15W/m·Ksourceat RT | 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 | 16µm/m·Ksourcemean, 20–100 °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 | 80µm growth | 60µm growth33% less |
| Specific heat | 500J/kg·Ksourceat RT | 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) | 3.8mm²/s | 13.6mm²/s3.58x faster |
| Thermal shock resistance | 902W/m | 5,473W/m6.07x more resistant |
| Max service temperature | 871°Csourcecontinuous, scaling limit | not sourced |
| Values for | 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 | 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 303 stronger than Steel AISI 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 275 MPa for Stainless 303 (35%).
Which is lighter, Stainless 303 or Steel AISI 1018?
Steel AISI 1018 is lighter: 7,861 kg/m³ against 7,900 kg/m³ for Stainless 303.
Which is stiffer, Stainless 303 or Steel AISI 1018?
Stainless 303 is stiffer: Young's modulus 200 GPa against 200 GPa for Steel AISI 1018, so the same part in Stainless 303 deflects less under the same load.
Which is lighter for the same job, Stainless 303 or Steel AISI 1018?
For the same stiffness or strength: Steel AISI 1018 is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Stainless 303 | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | about equal | about equal |
| Stiff beam (bending) | about equal | about equal |
| Stiff panel or plate | about equal | about equal |
| Strong rod or tie | 36% heavier | lighter |
| Strong beam | 23% heavier | lighter |
| Strong panel or plate | 17% 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 303 or Steel AISI 1018?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 15 W/m·K for Stainless 303.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 16 µm/m·K for Stainless 303.