Materials / Compare
Plastic PLA vs. Steel AISI 4340
Compare Plastic PLA vs. Steel AISI 4340 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 | 52.5MPasourcetypical | 1,035MPasourcetypical, transverse |
| Ultimate tensile strength | 52.5MPasourcetypical, peak stress (= stress at yield) | 1,140MPasourcetypical, transverse |
| Flexural strength | 96.8MPasourcetypical | not sourced |
| Elongation at break | 7.8%sourcetypical | 18%sourcetypical, transverse |
| Young's modulus (stiffness) | 3.25GPasourcetypical | 200GPasourceMIL-HDBK-5J design value (AISI 4340, quenched and tempered) |
| Density | 1,240kg/m³sourcetypical6.32x lighter | 7,840kg/m³sourcetypical |
| Strength to weight | 42.3kN·m/kg | 132kN·m/kg3.12x higher |
| Stiffness to weight | 2.62MN·m/kg | 25.5MN·m/kg9.73x higher |
| Poisson's ratio | not sourced | 0.32sourceMIL-HDBK-5J design value (AISI 4340, quenched and tempered) |
| Shear modulus | not sourced | 75.7GPa |
| Bulk modulus | not sourced | 185GPa |
| Speed of sound | 1,619m/s | 5,049m/s |
| Thermal | ||
| Thermal conductivity | 0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C | 37.5W/m·Ksourcetypical |
| Thermal expansion | not sourced | 11.3µm/m·Ksourcemean, -18 to 93 °C |
| 100 mm part over a 50 °C swing | not sourced | 56.5µm growth |
| Specific heat | 1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C | 448J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.0874mm²/s | 10.7mm²/s122x faster |
| Thermal shock resistance | not sourced | 11,678W/m |
| Melting point | 152°Csourcetypical | not sourced |
| Glass transition | 59.1°Csourcetypical | not sourced |
| Max service temperature | 58.8°CsourceHDT 0.455 MPa (printed specimens) | not sourced |
| Values for | Ultimaker PLA, 3D-printed specimens, XY (flat) orientation; 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 dated April 20, 2022. | Carpenter (Latrobe) Lescalloy 4340 VAC-ARC datasheet; mechanical row for 1100 °F temper; physical properties grade-level |
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 PLA is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic PLA stronger than Steel AISI 4340?
Steel AISI 4340 is stronger: its yield strength is 1,035 MPa against 52.5 MPa for Plastic PLA (19.7x).
Which is lighter, Plastic PLA or Steel AISI 4340?
Plastic PLA is lighter: 1,240 kg/m³ against 7,840 kg/m³ for Steel AISI 4340.
Which is stiffer, Plastic PLA or Steel AISI 4340?
Steel AISI 4340 is stiffer: Young's modulus 200 GPa against 3.25 GPa for Plastic PLA, so the same part in Steel AISI 4340 deflects less under the same load.
Which is lighter for the same job, Plastic PLA or Steel AISI 4340?
For the same stiffness or strength: Plastic PLA is lighter for a stiff panel or plate, strong panel or plate; Steel AISI 4340 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie, strong beam.
| Part that must be | Plastic PLA | Steel AISI 4340 |
|---|---|---|
| Stiff rod or tie (tension) | 9.73x heavier | lighter |
| Stiff beam (bending) | 24% heavier | lighter |
| Stiff panel or plate | lighter | 1.6x heavier |
| Strong rod or tie | 3.12x heavier | lighter |
| Strong beam | 15% heavier | lighter |
| Strong panel or plate | lighter | 42% 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 PLA or Steel AISI 4340?
Steel AISI 4340 conducts heat better: 37.5 W/m·K against 0.13 W/m·K for Plastic PLA.