Materials / Compare
Plastic Polycarbonate vs. Stainless 316
Compare Plastic Polycarbonate vs. Stainless 316 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 | 65MPasourcetypical, tensile yield | 265MPasourcetypical (representative), annealed 1.0 mm sheet |
| Ultimate tensile strength | 65MPasourcetypical, stress at break | 583MPasourcetypical (representative), annealed 1.0 mm sheet |
| Flexural strength | 97MPasourcetypical, flexural strength | not sourced |
| Elongation at break | 125%sourcetypical, strain at break | 61%sourcetypical (representative), annealed, in 2 in. (51 mm) |
| Young's modulus (stiffness) | 2.4GPasourcetypical | 200GPasourcetypical, in tension |
| Density | 1,200kg/m³sourcetypical6.69x lighter | 8,027kg/m³sourcetypical |
| Strength to weight | 54.2kN·m/kg1.64x higher | 33kN·m/kg |
| Stiffness to weight | 2MN·m/kg | 24.9MN·m/kg12.5x higher |
| Poisson's ratio | 0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1) | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 0.87GPa | 76.9GPa88.5x stiffer in shear |
| Bulk modulus | 3.33GPa | 167GPa |
| Speed of sound | 1,414m/s | 4,992m/s |
| Thermal | ||
| Thermal conductivity | 0.2W/m·Ksourcetypical, through-plane, 23 C | 14.6W/m·Ksource20–100 °C |
| Thermal expansion | 65µm/m·Ksourcetypical, 23-55 C, parallel and normal | 16.5µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 325µm growth | 82.5µm growth3.94x less |
| Specific heat | 1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766 | 450J/kg·Ksourceat 20 °C |
| Heats up and cools (diffusivity) | 0.142mm²/s | 4.04mm²/s28.4x faster |
| Thermal shock resistance | 51.7W/m | 821W/m15.9x more resistant |
| Melting point | not sourced | 1,390–1,440°Csourcemelting range |
| Glass transition | 144°Csourcetypical, DSC 10 C/min | not sourced |
| Max service temperature | 125°CsourceUL 746B RTI, tensile strength, 1.5 mm | 871–899°Csourceoxidation (scaling) limit in air |
| Values for | Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical values | ATI 316 (UNS S31600), annealed 1.0 mm sheet, ATI technical data sheet (2012); Poisson's ratio from the Nickel Institute/SCI structural stainless design manual |
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 Plastic Polycarbonate stronger than Stainless 316?
Stainless 316 is stronger: its yield strength is 265 MPa against 65 MPa for Plastic Polycarbonate (4.08x).
Which is lighter, Plastic Polycarbonate or Stainless 316?
Plastic Polycarbonate is lighter: 1,200 kg/m³ against 8,027 kg/m³ for Stainless 316.
Which is stiffer, Plastic Polycarbonate or Stainless 316?
Stainless 316 is stiffer: Young's modulus 200 GPa against 2.4 GPa for Plastic Polycarbonate, so the same part in Stainless 316 deflects less under the same load.
Which is lighter for the same job, Plastic Polycarbonate or Stainless 316?
For the same stiffness or strength: Plastic Polycarbonate is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Stainless 316 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic Polycarbonate | Stainless 316 |
|---|---|---|
| Stiff rod or tie (tension) | 12.5x heavier | lighter |
| Stiff beam (bending) | 36% heavier | lighter |
| Stiff panel or plate | lighter | 1.53x heavier |
| Strong rod or tie | lighter | 1.64x heavier |
| Strong beam | lighter | 2.62x heavier |
| Strong panel or plate | lighter | 3.31x 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 Polycarbonate or Stainless 316?
Stainless 316 conducts heat better: 14.6 W/m·K against 0.2 W/m·K for Plastic Polycarbonate.
Which expands less with temperature?
Stainless 316 expands less: 16.5 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.