Materials / Compare
Steel AISI 1018 vs. Plastic UHMWPE
Compare Steel AISI 1018 vs. Plastic UHMWPE 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 | 20MPasourcetypical, tensile stress at yield ISO 527, 50 mm/min |
| Ultimate tensile strength | 441MPasourceproducer-stated, cold drawn | 43MPasourcetypical, tensile stress at break ISO 527, 50 mm/min |
| Elongation at break | 15%sourcein 2 in (50.8 mm) | 465%sourcetypical, nominal elongation at break ISO 527 |
| 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) | 0.66GPasourcetypical, tensile modulus ISO 527, 1 mm/min |
| 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) | 930kg/m³sourcetypical |
| Strength to weight | 47.3kN·m/kg2.2x higher | 21.5kN·m/kg |
| Stiffness to weight | 25.4MN·m/kg35.8x higher | 0.71MN·m/kg |
| 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) | not sourced |
| Shear modulus | 75.7GPa | not sourced |
| Bulk modulus | 185GPa | not sourced |
| Speed of sound | 5,043m/s | 842m/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) | 0.4W/m·Ksourcetypical, unfilled (narrative value, generic Celanese UHMWPE) |
| Thermal expansion | 12µm/m·Ksourcebase material: unalloyed carbon steel, Ovako family table (S275JR, 'none alloyed structural steels', C <= 0.21%); mean 20-300 °C | 200µm/m·Ksourcetypical, 20 to 100 °C (generic Celanese UHMWPE) |
| 100 mm part over a 50 °C swing | 60µm growth16.7x less | 1,000µm 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) | not sourced |
| Heats up and cools (diffusivity) | 13.6mm²/s | not sourced |
| Thermal shock resistance | 5,473W/m | not sourced |
| Melting point | not sourced | 130–138°CsourceDSC 10 K/min |
| Max service temperature | not sourced | 80°Csourcerecommended max constant operating temperature |
| Values for | AISI 1018 cold drawn bar (Niagara LaSalle, cold-finished bar producer) | Celanese GUR 4120 (avg. molecular weight 4.7x10^6 g/mol), typical values on compression-molded specimens; CTE and thermal conductivity from Celanese's generic UHMWPE guide (grade not named) |
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 Plastic UHMWPE?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 20 MPa for Plastic UHMWPE (18.6x).
Which is lighter, Steel AISI 1018 or Plastic UHMWPE?
Plastic UHMWPE is lighter: 930 kg/m³ against 7,861 kg/m³ for Steel AISI 1018.
Which is stiffer, Steel AISI 1018 or Plastic UHMWPE?
Steel AISI 1018 is stiffer: Young's modulus 200 GPa against 0.66 GPa for Plastic UHMWPE, so the same part in Steel AISI 1018 deflects less under the same load.
Which is lighter for the same job, Steel AISI 1018 or Plastic UHMWPE?
For the same stiffness or strength: Steel AISI 1018 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie; Plastic UHMWPE is lighter for a stiff panel or plate, strong beam, strong panel or plate.
| Part that must be | Steel AISI 1018 | Plastic UHMWPE |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 35.8x heavier |
| Stiff beam (bending) | lighter | 2.06x heavier |
| Stiff panel or plate | 26% heavier | lighter |
| Strong rod or tie | lighter | 2.2x heavier |
| Strong beam | 20% heavier | lighter |
| Strong panel or plate | 1.96x 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, Steel AISI 1018 or Plastic UHMWPE?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 0.4 W/m·K for Plastic UHMWPE.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 200 µm/m·K for Plastic UHMWPE.