Materials / Compare
Iron vs. Plastic TPU
Compare Iron vs. Plastic TPU 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 | not given (tensile used) |
| Ultimate tensile strength | 290MPasourcetypical, SRA/recrystallization anneal | 23.7MPasourcetypical, stress at break |
| Flexural strength | not sourced | 4.1MPasourcetypical |
| Elongation at break | 38%sourcetypical, gauge 4D0 | not sourced |
| Young's modulus (stiffness) | 207GPasourcetypical, after SRA/recrystallization anneal | 0.067GPasourcetypical |
| Density | 7,860kg/m³sourcetypical | 1,220kg/m³sourcetypical6.44x lighter |
| Strength to weight | 23.7kN·m/kg22% higher | 19.4kN·m/kg |
| Stiffness to weight | 26.3MN·m/kg480x higher | 0.0549MN·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 | 234m/s |
| Thermal | ||
| Thermal conductivity | 73.2W/m·Ksourcetypical at 20 °C | not sourced |
| Thermal expansion | 13.7µm/m·Ksourcemean, 20-399 °C | not sourced |
| 100 mm part over a 50 °C swing | 68.5µm growth | not sourced |
| 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 | 217°Csourcetypical |
| Max service temperature | not sourced | 50.3°CsourceHDT 0.455 MPa (printed specimens) |
| 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. | Ultimaker TPU 95A, 3D-printed specimens, XY (flat); Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS (file v5.00), April 29, 2022. |
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.
Plastic TPU is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Iron stronger than Plastic TPU?
Iron is stronger: its yield strength is 186 MPa against tensile strength 23.7 MPa for Plastic TPU (7.85x).
Which is lighter, Iron or Plastic TPU?
Plastic TPU is lighter: 1,220 kg/m³ against 7,860 kg/m³ for Iron.
Which is stiffer, Iron or Plastic TPU?
Iron is stiffer: Young's modulus 207 GPa against 0.067 GPa for Plastic TPU, so the same part in Iron deflects less under the same load.
Which is lighter for the same job, Iron or Plastic TPU?
For the same stiffness or strength: Iron is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie; Plastic TPU is lighter for a strong beam, strong panel or plate.
| Part that must be | Iron | Plastic TPU |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 480x heavier |
| Stiff beam (bending) | lighter | 8.63x heavier |
| Stiff panel or plate | lighter | 2.26x heavier |
| Strong rod or tie | lighter | 22% heavier |
| Strong beam | 1.63x heavier | lighter |
| Strong panel or plate | 2.3x 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).