Materials / Compare
Plastic PETG vs. Stainless 303
Compare Plastic PETG vs. Stainless 303 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 | 275MPasourceOutokumpu typical (product P = hot rolled plate, transverse) |
| Ultimate tensile strength | 46.2MPasourcetypical, peak stress (= stress at yield) | 585MPasourceOutokumpu typical |
| Flexural strength | 78.9MPasourcetypical | not sourced |
| Elongation at break | 7.6%sourcetypical | 35%sourceOutokumpu typical, A5 |
| Young's modulus (stiffness) | 1.94GPasourcetypical | 200GPasourceat RT (Table 12) |
| Density | 1,270kg/m³sourcetypical | 7,900kg/m³sourceat RT |
| Strength to weight | 36.4kN·m/kg5% higher | 34.8kN·m/kg |
| Stiffness to weight | 1.53MN·m/kg | 25.3MN·m/kg16.6x higher |
| Poisson's ratio | not sourced | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | not sourced | 76.9GPa |
| Bulk modulus | not sourced | 167GPa |
| Speed of sound | 1,236m/s | 5,032m/s |
| Thermal | ||
| Thermal conductivity | 0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 15W/m·Ksourceat RT |
| Thermal expansion | 51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 16µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 255µm growth | 80µm growth3.19x less |
| Specific heat | 1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed) | 500J/kg·Ksourceat RT |
| Heats up and cools (diffusivity) | 0.127mm²/s | 3.8mm²/s29.9x faster |
| Thermal shock resistance | not sourced | 902W/m |
| Glass transition | 77.4°Csourcetypical | not sourced |
| Max service temperature | 76.2°CsourceHDT 0.455 MPa (printed specimens) | 871°Csourcecontinuous, scaling limit |
| 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. | 1.4305 / UNS S30300, Outokumpu typical values (hot rolled, solution annealed) from 'Steel Grades, Properties and Global Standards'; max service from Carpenter CarTech 303 datasheet |
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 303?
Stainless 303 is stronger: its yield strength is 275 MPa against 46.2 MPa for Plastic PETG (5.95x).
Which is lighter, Plastic PETG or Stainless 303?
Plastic PETG is lighter: 1,270 kg/m³ against 7,900 kg/m³ for Stainless 303.
Which is stiffer, Plastic PETG or Stainless 303?
Stainless 303 is stiffer: Young's modulus 200 GPa against 1.94 GPa for Plastic PETG, so the same part in Stainless 303 deflects less under the same load.
Which is lighter for the same job, Plastic PETG or Stainless 303?
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 303 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic PETG | Stainless 303 |
|---|---|---|
| Stiff rod or tie (tension) | 16.6x heavier | lighter |
| Stiff beam (bending) | 1.63x heavier | lighter |
| Stiff panel or plate | lighter | 33% heavier |
| Strong rod or tie | lighter | 5% heavier |
| Strong beam | lighter | 1.89x heavier |
| Strong panel or plate | lighter | 2.55x 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 303?
Stainless 303 conducts heat better: 15 W/m·K against 0.21 W/m·K for Plastic PETG.
Which expands less with temperature?
Stainless 303 expands less: 16 µm/m·K against 51 µm/m·K for Plastic PETG.