Materials / Compare
Iron vs. Plastic ABS (bulk/injection)
Compare Iron vs. Plastic ABS (bulk/injection) 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 | 45MPasourcetypical, tensile stress at yield 23 °C |
| Ultimate tensile strength | 290MPasourcetypical, SRA/recrystallization anneal | not sourced |
| Flexural strength | not sourced | 65MPasourcetypical, 23 °C |
| Elongation at break | 38%sourcetypical, gauge 4D0 | 10%sourcenominal strain at break, 23 °C |
| Young's modulus (stiffness) | 207GPasourcetypical, after SRA/recrystallization anneal | 2.3GPasourcetypical |
| Density | 7,860kg/m³sourcetypical | 1,040kg/m³sourcetypical7.56x lighter |
| Strength to weight | 23.7kN·m/kg | 43.3kN·m/kg1.83x higher |
| Stiffness to weight | 26.3MN·m/kg11.9x higher | 2.21MN·m/kg |
| Poisson's ratio | 0.282sourceNIST critically evaluated best value (polycrystalline iron) | 0.39sourcetypical, ABS family (Covestro Part and Mold Design guide, Table 3-1) |
| Shear modulus | 80.7GPa97.6x stiffer in shear | 0.827GPa |
| Bulk modulus | 158GPa | 3.48GPa |
| Speed of sound | 5,132m/s | 1,487m/s |
| Thermal | ||
| Thermal conductivity | 73.2W/m·Ksourcetypical at 20 °C | 0.17W/m·Ksourcetypical |
| Thermal expansion | 13.7µm/m·Ksourcemean, 20-399 °C | 80–110µm/m·Ksourcerange |
| 100 mm part over a 50 °C swing | 68.5µm growth6.93x less | 475µm growth |
| Specific heat | 450J/kg·Ksourcetypical | not sourced |
| Heats up and cools (diffusivity) | 20.7mm²/s | not sourced |
| Thermal shock resistance | 3,447W/m161x more resistant | 21.4W/m |
| Melting point | 1,532°Csourcetypical | not sourced |
| Max service temperature | not sourced | 94°CsourceHDT 1.8 MPa (annealed 4 h/80 °C) |
| 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. | INEOS Styrolution Terluran GP-22 general-purpose injection-molding ABS, ISO typical values (TDS revision 08/01/2022) |
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.
Questions
Is Iron stronger than Plastic ABS (bulk/injection)?
Iron is stronger: its yield strength is 186 MPa against 45 MPa for Plastic ABS (bulk/injection) (4.13x).
Which is lighter, Iron or Plastic ABS (bulk/injection)?
Plastic ABS (bulk/injection) is lighter: 1,040 kg/m³ against 7,860 kg/m³ for Iron.
Which is stiffer, Iron or Plastic ABS (bulk/injection)?
Iron is stiffer: Young's modulus 207 GPa against 2.3 GPa for Plastic ABS (bulk/injection), so the same part in Iron deflects less under the same load.
Which is lighter for the same job, Iron or Plastic ABS (bulk/injection)?
For the same stiffness or strength: Iron is lighter for a stiff rod or tie (tension), stiff beam (bending); Plastic ABS (bulk/injection) is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Iron | Plastic ABS (bulk/injection) |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 11.9x heavier |
| Stiff beam (bending) | lighter | 26% heavier |
| Stiff panel or plate | 1.69x heavier | lighter |
| Strong rod or tie | 1.83x heavier | lighter |
| Strong beam | 2.93x heavier | lighter |
| Strong panel or plate | 3.72x 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 ABS (bulk/injection)?
Iron conducts heat better: 73.2 W/m·K against 0.17 W/m·K for Plastic ABS (bulk/injection).
Which expands less with temperature?
Iron expands less: 13.7 µm/m·K against 95 µm/m·K for Plastic ABS (bulk/injection).