Materials / Compare
Iron vs. Plastic PLA
Compare Iron vs. Plastic PLA 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 | 186MPasourcetypical (0.2% YS), hot rolled + SRA/recrystallization anneal | 52.5MPasourcetypical |
| Ultimate tensile strength | 290MPasourcetypical, SRA/recrystallization anneal | 52.5MPasourcetypical, peak stress (= stress at yield) |
| Flexural strength | not sourced | 96.8MPasourcetypical |
| Elongation at break | 38%sourcetypical, gauge 4D0 | 7.8%sourcetypical |
| Young's modulus (stiffness) | 207GPasourcetypical, after SRA/recrystallization anneal | 3.25GPasourcetypical |
| Density | 7,860kg/m³sourcetypical | 1,240kg/m³sourcetypical6.34x lighter |
| Strength to weight | 23.7kN·m/kg | 42.3kN·m/kg1.79x higher |
| Stiffness to weight | 26.3MN·m/kg10x higher | 2.62MN·m/kg |
| Poisson's ratio | 0.282sourceNIST critically evaluated best value (polycrystalline iron) | not sourced |
| Shear modulus | 80.7GPa | not sourced |
| Bulk modulus | 158GPa | not sourced |
| Speed of sound | 5,132m/s | 1,619m/s |
| Thermal | ||
| Thermal conductivity | 73.2W/m·Ksourcetypical at 20 °C | 0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C |
| Thermal expansion | 13.7µm/m·Ksourcemean, 20-399 °C | not sourced |
| 100 mm part over a 50 °C swing | 68.5µm growth | not sourced |
| Specific heat | 450J/kg·Ksourcetypical | 1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C |
| Heats up and cools (diffusivity) | 20.7mm²/s237x faster | 0.0874mm²/s |
| Thermal shock resistance | 3,447W/m | not sourced |
| Melting point | 1,532°Csourcetypical | 152°Csourcetypical |
| Glass transition | not sourced | 59.1°Csourcetypical |
| Max service temperature | not sourced | 58.8°CsourceHDT 0.455 MPa (printed specimens) |
| Values for | Cleveland-Cliffs / AK Steel ARMCO Pure Iron Product Data Bulletin (07/2022): Table 1 typical physical properties, Table 2 typical mechanical properties after SRA/recrystallization anneal. | 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. |
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 Iron stronger than Plastic PLA?
Iron is stronger: its yield strength is 186 MPa against 52.5 MPa for Plastic PLA (3.54x).
Which is lighter, Iron or Plastic PLA?
Plastic PLA is lighter: 1,240 kg/m³ against 7,860 kg/m³ for Iron.
Which is stiffer, Iron or Plastic PLA?
Iron is stiffer: Young's modulus 207 GPa against 3.25 GPa for Plastic PLA, so the same part in Iron deflects less under the same load.
Which is lighter for the same job, Iron or Plastic PLA?
For the same stiffness or strength: Iron is lighter for a stiff rod or tie (tension), stiff beam (bending); Plastic PLA is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Iron | Plastic PLA |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 10x heavier |
| Stiff beam (bending) | lighter | 26% heavier |
| Stiff panel or plate | 1.59x heavier | lighter |
| Strong rod or tie | 1.79x heavier | lighter |
| Strong beam | 2.73x heavier | lighter |
| Strong panel or plate | 3.37x 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).
Which conducts heat better, Iron or Plastic PLA?
Iron conducts heat better: 73.2 W/m·K against 0.13 W/m·K for Plastic PLA.