Materials / Compare
Plastic PLA vs. Steel
Compare Plastic PLA vs. Steel 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 | 385MPasourcetypical: mean of 20,295 A992 flange mill-test coupons (1998 SSPC survey), as reported by AISC |
| Ultimate tensile strength | 52.5MPasourcetypical, peak stress (= stress at yield) | 505MPasourcetypical: mean of 20,295 A992 flange mill-test coupons (1998 SSPC survey) |
| Flexural strength | 96.8MPasourcetypical | not sourced |
| Elongation at break | 7.8%sourcetypical | not sourced |
| Young's modulus (stiffness) | 3.25GPasourcetypical | 200GPasourcedesign value (AISC 360-16) |
| Density | 1,240kg/m³sourcetypical | 7,850kg/m³sourcenominal (constructional data) |
| Strength to weight | 42.3kN·m/kg | 49kN·m/kg16% higher |
| Stiffness to weight | 2.62MN·m/kg | 25.5MN·m/kg9.72x higher |
| Poisson's ratio | not sourced | 0.3sourcedesign value (AISC 360-16 Commentary) |
| Shear modulus | not sourced | 76.9GPa |
| Bulk modulus | not sourced | 167GPa |
| Speed of sound | 1,619m/s | 5,048m/s |
| Thermal | ||
| Thermal conductivity | 0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C | 48W/m·Ksourcenominal at 20 °C |
| Thermal expansion | not sourced | 12µm/m·Ksourcenominal (constructional data, no temperature range stated) |
| 100 mm part over a 50 °C swing | not sourced | 60µm growth |
| Specific heat | 1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C | 460–480J/kg·Ksourcebase material: EN S275JR unalloyed structural steel (the EN counterpart of A36), typical, 50/100 °C |
| Heats up and cools (diffusivity) | 0.0874mm²/s | 13mm²/s149x faster |
| Thermal shock resistance | not sourced | 5,390W/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. | Generic structural steel, cited as ASTM A992 (the current US structural grade): ASTM A992 W-shapes; Fy/Fu specified minimums from AISC publications (AISC 360-16 Commentary; Modern Steel Construction); elastic constants AISC 360; physical constants from the bauforumstahl structural-steel EPD, which names A992 among covered product standards. |
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?
Steel is stronger: its yield strength is 385 MPa against 52.5 MPa for Plastic PLA (7.33x).
Which is lighter, Plastic PLA or Steel?
Plastic PLA is lighter: 1,240 kg/m³ against 7,850 kg/m³ for Steel.
Which is stiffer, Plastic PLA or Steel?
Steel is stiffer: Young's modulus 200 GPa against 3.25 GPa for Plastic PLA, so the same part in Steel deflects less under the same load.
Which is lighter for the same job, Plastic PLA or Steel?
For the same stiffness or strength: Plastic PLA is lighter for a stiff panel or plate, strong beam, strong panel or plate; Steel is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic PLA | Steel |
|---|---|---|
| Stiff rod or tie (tension) | 9.72x heavier | lighter |
| Stiff beam (bending) | 24% heavier | lighter |
| Stiff panel or plate | lighter | 1.6x heavier |
| Strong rod or tie | 16% heavier | lighter |
| Strong beam | lighter | 1.68x heavier |
| Strong panel or plate | lighter | 2.34x 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?
Steel conducts heat better: 48 W/m·K against 0.13 W/m·K for Plastic PLA.