Materials / Compare
Plastic Polypropylene vs. Stainless 316
Compare Plastic Polypropylene 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 | 33MPasourcetypical, tensile stress at yield ISO 527 | 265MPasourcetypical (representative), annealed 1.0 mm sheet |
| Ultimate tensile strength | not sourced | 583MPasourcetypical (representative), annealed 1.0 mm sheet |
| Elongation at break | not sourced | 61%sourcetypical (representative), annealed, in 2 in. (51 mm) |
| Young's modulus (stiffness) | 1.45GPasourcetypical, tensile modulus ISO 527 | 200GPasourcetypical, in tension |
| Density | 900kg/m³sourcetypical, 23 °C ISO 1183-1 | 8,027kg/m³sourcetypical |
| Strength to weight | 36.7kN·m/kg11% higher | 33kN·m/kg |
| Stiffness to weight | 1.61MN·m/kg | 24.9MN·m/kg15.5x higher |
| Poisson's ratio | 0.42sourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 0.511GPa | 76.9GPa151x stiffer in shear |
| Bulk modulus | 3.02GPa | 167GPa |
| Speed of sound | 1,269m/s | 4,992m/s |
| Thermal | ||
| Thermal conductivity | 0.17–0.22W/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 14.6W/m·Ksource20–100 °C |
| Thermal expansion | 80–100µm/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 16.5µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 450µm growth | 82.5µm growth5.45x less |
| Specific heat | not sourced | 450J/kg·Ksourceat 20 °C |
| Heats up and cools (diffusivity) | not sourced | 4.04mm²/s |
| Thermal shock resistance | 28.6W/m | 821W/m28.7x more resistant |
| Melting point | not sourced | 1,390–1,440°Csourcemelting range |
| Max service temperature | 90°CsourceHDT 0.45 MPa (ISO 75B), unannealed | 871–899°Csourceoxidation (scaling) limit in air |
| Values for | LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO 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 Polypropylene stronger than Stainless 316?
Stainless 316 is stronger: its yield strength is 265 MPa against 33 MPa for Plastic Polypropylene (8.03x).
Which is lighter, Plastic Polypropylene or Stainless 316?
Plastic Polypropylene is lighter: 900 kg/m³ against 8,027 kg/m³ for Stainless 316.
Which is stiffer, Plastic Polypropylene or Stainless 316?
Stainless 316 is stiffer: Young's modulus 200 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in Stainless 316 deflects less under the same load.
Which is lighter for the same job, Plastic Polypropylene or Stainless 316?
For the same stiffness or strength: Plastic Polypropylene 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 Polypropylene | Stainless 316 |
|---|---|---|
| Stiff rod or tie (tension) | 15.5x heavier | lighter |
| Stiff beam (bending) | 32% heavier | lighter |
| Stiff panel or plate | lighter | 1.73x heavier |
| Strong rod or tie | lighter | 11% heavier |
| Strong beam | lighter | 2.22x heavier |
| Strong panel or plate | lighter | 3.15x 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 Polypropylene or Stainless 316?
Stainless 316 conducts heat better: 14.6 W/m·K against 0.195 W/m·K for Plastic Polypropylene.
Which expands less with temperature?
Stainless 316 expands less: 16.5 µm/m·K against 90 µm/m·K for Plastic Polypropylene.