Materials / Compare
Plastic PETG vs. Stainless 304
Compare Plastic PETG vs. Stainless 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 | 46.2MPasourcetypical | 241MPasourcetypical, annealed, 70 °F (21 °C) |
| Ultimate tensile strength | 46.2MPasourcetypical, peak stress (= stress at yield) | 586MPasourcetypical, annealed, 70 °F (21 °C) |
| Flexural strength | 78.9MPasourcetypical | not sourced |
| Elongation at break | 7.6%sourcetypical | 55%sourcetypical, annealed, in 2 in. (50.8 mm) |
| Young's modulus (stiffness) | 1.94GPasourcetypical | 193GPasourcetypical, in tension |
| Density | 1,270kg/m³sourcetypical6.32x lighter | 8,030kg/m³sourcetypical |
| Strength to weight | 36.4kN·m/kg21% higher | 30kN·m/kg |
| Stiffness to weight | 1.53MN·m/kg | 24MN·m/kg15.7x 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 | 1,236m/s | 4,903m/s |
| Thermal | ||
| Thermal conductivity | 0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 16.2W/m·Ksourceat 100 °C |
| Thermal expansion | 51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 16.9µm/m·Ksourcemean, 0–100 °C |
| 100 mm part over a 50 °C swing | 255µm growth | 84.5µm growth3.02x less |
| Specific heat | 1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed) | 500J/kg·Ksourcemean, 0–100 °C |
| Heats up and cools (diffusivity) | 0.127mm²/s | 4.03mm²/s31.7x faster |
| Thermal shock resistance | not sourced | 838W/m |
| Melting point | not sourced | 1,399–1,454°Csourcemelting range |
| Glass transition | 77.4°Csourcetypical | not sourced |
| Max service temperature | 76.2°CsourceHDT 0.455 MPa (printed specimens) | 899°Csourcecontinuous, oxidation (scaling) limit in air |
| Values for | Ultimaker PETG, 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 v1.00, April 29, 2022. | 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.
Plastic PETG is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic PETG stronger than Stainless 304?
Stainless 304 is stronger: its yield strength is 241 MPa against 46.2 MPa for Plastic PETG (5.22x).
Which is lighter, Plastic PETG or Stainless 304?
Plastic PETG is lighter: 1,270 kg/m³ against 8,030 kg/m³ for Stainless 304.
Which is stiffer, Plastic PETG or Stainless 304?
Stainless 304 is stiffer: Young's modulus 193 GPa against 1.94 GPa for Plastic PETG, so the same part in Stainless 304 deflects less under the same load.
Which is lighter for the same job, Plastic PETG or Stainless 304?
For the same stiffness or strength: Plastic PETG is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Stainless 304 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic PETG | Stainless 304 |
|---|---|---|
| Stiff rod or tie (tension) | 15.7x heavier | lighter |
| Stiff beam (bending) | 1.58x heavier | lighter |
| Stiff panel or plate | lighter | 36% heavier |
| Strong rod or tie | lighter | 21% heavier |
| Strong beam | lighter | 2.1x heavier |
| Strong panel or plate | lighter | 2.77x 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 PETG or Stainless 304?
Stainless 304 conducts heat better: 16.2 W/m·K against 0.21 W/m·K for Plastic PETG.
Which expands less with temperature?
Stainless 304 expands less: 16.9 µm/m·K against 51 µm/m·K for Plastic PETG.