Materials / Compare
Plastic UHMWPE vs. Stainless Steel 304
Compare Plastic UHMWPE vs. Stainless Steel 304 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 | 241MPasourcetypical, annealed, 70 °F (21 °C) |
| Ultimate tensile strength | 43MPasourcetypical, tensile stress at break ISO 527, 50 mm/min | 586MPasourcetypical, annealed, 70 °F (21 °C) |
| Elongation at break | 465%sourcetypical, nominal elongation at break ISO 527 | 55%sourcetypical, annealed, in 2 in. (50.8 mm) |
| Young's modulus (stiffness) | 0.66GPasourcetypical, tensile modulus ISO 527, 1 mm/min | 193GPasourcetypical, in tension |
| Density | 930kg/m³sourcetypical8.63x lighter | 8,030kg/m³sourcetypical |
| Strength to weight | 21.5kN·m/kg | 30kN·m/kg40% higher |
| Stiffness to weight | 0.71MN·m/kg | 24MN·m/kg33.9x higher |
| Poisson's ratio | not sourced | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | not sourced | 74.2GPa |
| Bulk modulus | not sourced | 161GPa |
| Speed of sound | 842m/s | 4,903m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical, unfilled (narrative value, generic Celanese UHMWPE) | 16.2W/m·Ksourceat 100 °C |
| Thermal expansion | 200µm/m·Ksourcetypical, 20 to 100 °C (generic Celanese UHMWPE) | 16.9µm/m·Ksourcemean, 0–100 °C |
| 100 mm part over a 50 °C swing | 1,000µm growth | 84.5µm growth11.8x less |
| Specific heat | not sourced | 500J/kg·Ksourcemean, 0–100 °C |
| Heats up and cools (diffusivity) | not sourced | 4.03mm²/s |
| Thermal shock resistance | not sourced | 838W/m |
| Melting point | 130–138°CsourceDSC 10 K/min | 1,399–1,454°Csourcemelting range |
| Max service temperature | 80°Csourcerecommended max constant operating temperature | 899°Csourcecontinuous, oxidation (scaling) limit in air |
| 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) | 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 |
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 Stainless Steel 304?
Stainless Steel 304 is stronger: its yield strength is 241 MPa against 20 MPa for Plastic UHMWPE (12.1x).
Which is lighter, Plastic UHMWPE or Stainless Steel 304?
Plastic UHMWPE is lighter: 930 kg/m³ against 8,030 kg/m³ for Stainless Steel 304.
Which is stiffer, Plastic UHMWPE or Stainless Steel 304?
Stainless Steel 304 is stiffer: Young's modulus 193 GPa against 0.66 GPa for Plastic UHMWPE, so the same part in Stainless Steel 304 deflects less under the same load.
Which is lighter for the same job, Plastic UHMWPE or Stainless Steel 304?
For the same stiffness or strength: Plastic UHMWPE is lighter for a stiff panel or plate, strong beam, strong panel or plate; Stainless Steel 304 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic UHMWPE | Stainless Steel 304 |
|---|---|---|
| Stiff rod or tie (tension) | 33.9x heavier | lighter |
| Stiff beam (bending) | 1.98x heavier | lighter |
| Stiff panel or plate | lighter | 30% heavier |
| Strong rod or tie | 40% heavier | lighter |
| Strong beam | lighter | 1.64x heavier |
| Strong panel or plate | lighter | 2.49x 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 Stainless Steel 304?
Stainless Steel 304 conducts heat better: 16.2 W/m·K against 0.4 W/m·K for Plastic UHMWPE.
Which expands less with temperature?
Stainless Steel 304 expands less: 16.9 µm/m·K against 200 µm/m·K for Plastic UHMWPE.