Materials / Compare
Plastic UHMWPE vs. Steel AISI 1018
Compare Plastic UHMWPE 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 | 20MPasourcetypical, tensile stress at yield ISO 527, 50 mm/min | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 43MPasourcetypical, tensile stress at break ISO 527, 50 mm/min | 441MPasourceproducer-stated, cold drawn |
| Elongation at break | 465%sourcetypical, nominal elongation at break ISO 527 | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 0.66GPasourcetypical, tensile modulus ISO 527, 1 mm/min | 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 | 930kg/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 | 21.5kN·m/kg | 47.3kN·m/kg2.2x higher |
| Stiffness to weight | 0.71MN·m/kg | 25.4MN·m/kg35.8x higher |
| Poisson's ratio | not sourced | 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 | not sourced | 75.7GPa |
| Bulk modulus | not sourced | 185GPa |
| Speed of sound | 842m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical, unfilled (narrative value, generic Celanese UHMWPE) | 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 | 200µm/m·Ksourcetypical, 20 to 100 °C (generic Celanese UHMWPE) | 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 | 1,000µm growth | 60µm growth16.7x less |
| Specific heat | not sourced | 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) | not sourced | 13.6mm²/s |
| Thermal shock resistance | not sourced | 5,473W/m |
| Melting point | 130–138°CsourceDSC 10 K/min | not sourced |
| Max service temperature | 80°Csourcerecommended max constant operating temperature | not sourced |
| Values for | 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) | 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 Plastic UHMWPE stronger than Steel AISI 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 20 MPa for Plastic UHMWPE (18.6x).
Which is lighter, Plastic UHMWPE or Steel AISI 1018?
Plastic UHMWPE is lighter: 930 kg/m³ against 7,861 kg/m³ for Steel AISI 1018.
Which is stiffer, Plastic UHMWPE or Steel AISI 1018?
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, Plastic UHMWPE or Steel AISI 1018?
For the same stiffness or strength: Plastic UHMWPE is lighter for a stiff panel or plate, strong beam, strong panel or plate; Steel AISI 1018 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic UHMWPE | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | 35.8x heavier | lighter |
| Stiff beam (bending) | 2.06x heavier | lighter |
| Stiff panel or plate | lighter | 26% heavier |
| Strong rod or tie | 2.2x heavier | lighter |
| Strong beam | lighter | 20% heavier |
| Strong panel or plate | lighter | 1.96x heavier |
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, Plastic UHMWPE or Steel AISI 1018?
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.