Materials / Compare
Steel vs. Plastic TPU
Compare Steel 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 | 385MPasourcetypical: mean of 20,295 A992 flange mill-test coupons (1998 SSPC survey), as reported by AISC | not given (tensile used) |
| Ultimate tensile strength | 505MPasourcetypical: mean of 20,295 A992 flange mill-test coupons (1998 SSPC survey) | 23.7MPasourcetypical, stress at break |
| Flexural strength | not sourced | 4.1MPasourcetypical |
| Elongation at break | not sourced | not sourced |
| Young's modulus (stiffness) | 200GPasourcedesign value (AISC 360-16) | 0.067GPasourcetypical |
| Density | 7,850kg/m³sourcenominal (constructional data) | 1,220kg/m³sourcetypical |
| Strength to weight | 49kN·m/kg2.52x higher | 19.4kN·m/kg |
| Stiffness to weight | 25.5MN·m/kg464x higher | 0.0549MN·m/kg |
| Poisson's ratio | 0.3sourcedesign value (AISC 360-16 Commentary) | not sourced |
| Shear modulus | 76.9GPa | not sourced |
| Bulk modulus | 167GPa | not sourced |
| Speed of sound | 5,048m/s | 234m/s |
| Thermal | ||
| Thermal conductivity | 48W/m·Ksourcenominal at 20 °C | not sourced |
| Thermal expansion | 12µm/m·Ksourcenominal (constructional data, no temperature range stated) | not sourced |
| 100 mm part over a 50 °C swing | 60µm growth | not sourced |
| Specific heat | 460–480J/kg·Ksourcebase material: EN S275JR unalloyed structural steel (the EN counterpart of A36), typical, 50/100 °C | not sourced |
| Heats up and cools (diffusivity) | 13mm²/s | not sourced |
| Thermal shock resistance | 5,390W/m | not sourced |
| Melting point | not sourced | 217°Csourcetypical |
| Max service temperature | not sourced | 50.3°CsourceHDT 0.455 MPa (printed specimens) |
| Values for | Generic structural steel, cited as ASTM A992 (the current US structural grade): ASTM A992 W-shapes; Fy/Fu specified minimums from AISC publications (AISC 360-16 Commentary; Modern Steel Construction); elastic constants AISC 360; physical constants from the bauforumstahl structural-steel EPD, which names A992 among covered product standards. | 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 Steel stronger than Plastic TPU?
Steel is stronger: its yield strength is 385 MPa against tensile strength 23.7 MPa for Plastic TPU (16.2x).
Which is lighter, Steel or Plastic TPU?
Plastic TPU is lighter: 1,220 kg/m³ against 7,850 kg/m³ for Steel.
Which is stiffer, Steel or Plastic TPU?
Steel is stiffer: Young's modulus 200 GPa against 0.067 GPa for Plastic TPU, so the same part in Steel deflects less under the same load.
Which is lighter for the same job, Steel or Plastic TPU?
For the same stiffness or strength: Steel 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 panel or plate.
| Part that must be | Steel | Plastic TPU |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 464x heavier |
| Stiff beam (bending) | lighter | 8.49x heavier |
| Stiff panel or plate | lighter | 2.24x heavier |
| Strong rod or tie | lighter | 2.52x heavier |
| Strong beam | about equal | about equal |
| Strong panel or plate | 1.6x 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).