Materials / Compare
Plastic PETG vs. Steel AISI 1018
Compare Plastic PETG vs. Steel AISI 1018 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 | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 46.2MPasourcetypical, peak stress (= stress at yield) | 441MPasourceproducer-stated, cold drawn |
| Flexural strength | 78.9MPasourcetypical | not sourced |
| Elongation at break | 7.6%sourcetypical | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 1.94GPasourcetypical | 200GPasourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Density | 1,270kg/m³sourcetypical | 7,861kg/m³sourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Strength to weight | 36.4kN·m/kg | 47.3kN·m/kg30% higher |
| Stiffness to weight | 1.53MN·m/kg | 25.4MN·m/kg16.7x higher |
| Poisson's ratio | not sourced | 0.32sourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Shear modulus | not sourced | 75.7GPa |
| Bulk modulus | not sourced | 185GPa |
| Speed of sound | 1,236m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 51.9W/m·Ksourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Thermal expansion | 51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 12µm/m·Ksourcebase material: unalloyed carbon steel, Ovako family table (S275JR, 'none alloyed structural steels', C <= 0.21%); mean 20-300 °C |
| 100 mm part over a 50 °C swing | 255µm growth | 60µm growth4.25x less |
| Specific heat | 1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed) | 486J/kg·Ksourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Heats up and cools (diffusivity) | 0.127mm²/s | 13.6mm²/s107x faster |
| Thermal shock resistance | not sourced | 5,473W/m |
| Glass transition | 77.4°Csourcetypical | not sourced |
| Max service temperature | 76.2°CsourceHDT 0.455 MPa (printed specimens) | not sourced |
| 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. | AISI 1018 cold drawn bar (Niagara LaSalle, cold-finished bar producer) |
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 Steel AISI 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 46.2 MPa for Plastic PETG (8.05x).
Which is lighter, Plastic PETG or Steel AISI 1018?
Plastic PETG is lighter: 1,270 kg/m³ against 7,861 kg/m³ for Steel AISI 1018.
Which is stiffer, Plastic PETG or Steel AISI 1018?
Steel AISI 1018 is stiffer: Young's modulus 200 GPa against 1.94 GPa for Plastic PETG, so the same part in Steel AISI 1018 deflects less under the same load.
Which is lighter for the same job, Plastic PETG or Steel AISI 1018?
For the same stiffness or strength: Plastic PETG is lighter for a stiff panel or plate, strong beam, strong panel or plate; Steel AISI 1018 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic PETG | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | 16.7x heavier | lighter |
| Stiff beam (bending) | 1.64x heavier | lighter |
| Stiff panel or plate | lighter | 32% heavier |
| Strong rod or tie | 30% heavier | lighter |
| Strong beam | lighter | 1.54x heavier |
| Strong panel or plate | lighter | 2.18x 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 Steel AISI 1018?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 0.21 W/m·K for Plastic PETG.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 51 µm/m·K for Plastic PETG.