Materials / Compare
Plastic ABS vs. Steel AISI 4340
Compare Plastic ABS 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 | 38.1MPasourcetypical | 1,035MPasourcetypical, transverse |
| Ultimate tensile strength | 38.1MPasourcetypical, peak stress (= stress at yield) | 1,140MPasourcetypical, transverse |
| Flexural strength | 61.1MPasourcetypical | not sourced |
| Elongation at break | 4.6%sourcetypical | 18%sourcetypical, transverse |
| Young's modulus (stiffness) | 1.96GPasourcetypical | 200GPasourceMIL-HDBK-5J design value (AISI 4340, quenched and tempered) |
| Density | 1,100kg/m³sourcetypical7.13x lighter | 7,840kg/m³sourcetypical |
| Strength to weight | 34.6kN·m/kg | 132kN·m/kg3.81x higher |
| Stiffness to weight | 1.78MN·m/kg | 25.5MN·m/kg14.3x higher |
| Poisson's ratio | 0.39sourcebase material: ABS family typical (Covestro Part and Mold Design guide, Table 3-1) | 0.32sourceMIL-HDBK-5J design value (AISI 4340, quenched and tempered) |
| Shear modulus | 0.706GPa | 75.7GPa107x stiffer in shear |
| Bulk modulus | 2.97GPa | 185GPa |
| Speed of sound | 1,336m/s | 5,049m/s |
| Thermal | ||
| Thermal conductivity | 0.17W/m·Ksourcebase material: INEOS Styrolution Terluran GP-22 injection-molding ABS, typical | 37.5W/m·Ksourcetypical |
| Thermal expansion | 80–110µm/m·Ksourcebase material: INEOS Styrolution Terluran GP-22 injection-molding ABS, range | 11.3µm/m·Ksourcemean, -18 to 93 °C |
| 100 mm part over a 50 °C swing | 475µm growth | 56.5µm growth8.41x less |
| Specific heat | not sourced | 448J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | not sourced | 10.7mm²/s |
| Thermal shock resistance | 21.2W/m | 11,678W/m551x more resistant |
| Glass transition | 101°Csourcetypical | not sourced |
| Max service temperature | 86.6°CsourceHDT 0.455 MPa (printed specimens) | not sourced |
| Values for | Ultimaker ABS, 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 v5.00, 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 ABS is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic ABS stronger than Steel AISI 4340?
Steel AISI 4340 is stronger: its yield strength is 1,035 MPa against 38.1 MPa for Plastic ABS (27.2x).
Which is lighter, Plastic ABS or Steel AISI 4340?
Plastic ABS is lighter: 1,100 kg/m³ against 7,840 kg/m³ for Steel AISI 4340.
Which is stiffer, Plastic ABS or Steel AISI 4340?
Steel AISI 4340 is stiffer: Young's modulus 200 GPa against 1.96 GPa for Plastic ABS, so the same part in Steel AISI 4340 deflects less under the same load.
Which is lighter for the same job, Plastic ABS or Steel AISI 4340?
For the same stiffness or strength: Plastic ABS 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 ABS | Steel AISI 4340 |
|---|---|---|
| Stiff rod or tie (tension) | 14.3x heavier | lighter |
| Stiff beam (bending) | 42% heavier | lighter |
| Stiff panel or plate | lighter | 1.53x heavier |
| Strong rod or tie | 3.81x heavier | lighter |
| Strong beam | 27% heavier | lighter |
| Strong panel or plate | lighter | 37% 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 ABS or Steel AISI 4340?
Steel AISI 4340 conducts heat better: 37.5 W/m·K against 0.17 W/m·K for Plastic ABS.
Which expands less with temperature?
Steel AISI 4340 expands less: 11.3 µm/m·K against 95 µm/m·K for Plastic ABS.