Materials / Compare
Iron vs. Plastic UHMWPE
Compare Iron 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 | 186MPasourcetypical (0.2% YS), hot rolled + SRA/recrystallization anneal | 20MPasourcetypical, tensile stress at yield ISO 527, 50 mm/min |
| Ultimate tensile strength | 290MPasourcetypical, SRA/recrystallization anneal | 43MPasourcetypical, tensile stress at break ISO 527, 50 mm/min |
| Elongation at break | 38%sourcetypical, gauge 4D0 | 465%sourcetypical, nominal elongation at break ISO 527 |
| Young's modulus (stiffness) | 207GPasourcetypical, after SRA/recrystallization anneal | 0.66GPasourcetypical, tensile modulus ISO 527, 1 mm/min |
| Density | 7,860kg/m³sourcetypical | 930kg/m³sourcetypical8.45x lighter |
| Strength to weight | 23.7kN·m/kg10% higher | 21.5kN·m/kg |
| Stiffness to weight | 26.3MN·m/kg37.1x higher | 0.71MN·m/kg |
| Poisson's ratio | 0.282sourceNIST critically evaluated best value (polycrystalline iron) | not sourced |
| Shear modulus | 80.7GPa | not sourced |
| Bulk modulus | 158GPa | not sourced |
| Speed of sound | 5,132m/s | 842m/s |
| Thermal | ||
| Thermal conductivity | 73.2W/m·Ksourcetypical at 20 °C | 0.4W/m·Ksourcetypical, unfilled (narrative value, generic Celanese UHMWPE) |
| Thermal expansion | 13.7µm/m·Ksourcemean, 20-399 °C | 200µm/m·Ksourcetypical, 20 to 100 °C (generic Celanese UHMWPE) |
| 100 mm part over a 50 °C swing | 68.5µm growth14.6x less | 1,000µm growth |
| Specific heat | 450J/kg·Ksourcetypical | not sourced |
| Heats up and cools (diffusivity) | 20.7mm²/s | not sourced |
| Thermal shock resistance | 3,447W/m | not sourced |
| Melting point | 1,532°Csourcetypical | 130–138°CsourceDSC 10 K/min |
| Max service temperature | not sourced | 80°Csourcerecommended max constant operating temperature |
| Values for | Cleveland-Cliffs / AK Steel ARMCO Pure Iron Product Data Bulletin (07/2022): Table 1 typical physical properties, Table 2 typical mechanical properties after SRA/recrystallization anneal. | 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 Iron stronger than Plastic UHMWPE?
Iron is stronger: its yield strength is 186 MPa against 20 MPa for Plastic UHMWPE (9.3x).
Which is lighter, Iron or Plastic UHMWPE?
Plastic UHMWPE is lighter: 930 kg/m³ against 7,860 kg/m³ for Iron.
Which is stiffer, Iron or Plastic UHMWPE?
Iron is stiffer: Young's modulus 207 GPa against 0.66 GPa for Plastic UHMWPE, so the same part in Iron deflects less under the same load.
Which is lighter for the same job, Iron or Plastic UHMWPE?
For the same stiffness or strength: Iron 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 | Iron | Plastic UHMWPE |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 37.1x heavier |
| Stiff beam (bending) | lighter | 2.1x heavier |
| Stiff panel or plate | 24% heavier | lighter |
| Strong rod or tie | lighter | 10% heavier |
| Strong beam | 1.91x heavier | lighter |
| Strong panel or plate | 2.77x 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, Iron or Plastic UHMWPE?
Iron conducts heat better: 73.2 W/m·K against 0.4 W/m·K for Plastic UHMWPE.
Which expands less with temperature?
Iron expands less: 13.7 µm/m·K against 200 µm/m·K for Plastic UHMWPE.