Materials / Compare
Plastic Polypropylene vs. Stainless 303
Compare Plastic Polypropylene vs. Stainless 303 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 | 275MPasourceOutokumpu typical (product P = hot rolled plate, transverse) |
| Ultimate tensile strength | not sourced | 585MPasourceOutokumpu typical |
| Elongation at break | not sourced | 35%sourceOutokumpu typical, A5 |
| Young's modulus (stiffness) | 1.45GPasourcetypical, tensile modulus ISO 527 | 200GPasourceat RT (Table 12) |
| Density | 900kg/m³sourcetypical, 23 °C ISO 1183-1 | 7,900kg/m³sourceat RT |
| Strength to weight | 36.7kN·m/kg5% higher | 34.8kN·m/kg |
| Stiffness to weight | 1.61MN·m/kg | 25.3MN·m/kg15.7x 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 | 5,032m/s |
| Thermal | ||
| Thermal conductivity | 0.17–0.22W/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 15W/m·Ksourceat RT |
| Thermal expansion | 80–100µm/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 16µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 450µm growth | 80µm growth5.63x less |
| Specific heat | not sourced | 500J/kg·Ksourceat RT |
| Heats up and cools (diffusivity) | not sourced | 3.8mm²/s |
| Thermal shock resistance | 28.6W/m | 902W/m31.6x more resistant |
| Max service temperature | 90°CsourceHDT 0.45 MPa (ISO 75B), unannealed | 871°Csourcecontinuous, scaling limit |
| Values for | LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values | 1.4305 / UNS S30300, Outokumpu typical values (hot rolled, solution annealed) from 'Steel Grades, Properties and Global Standards'; max service from Carpenter CarTech 303 datasheet |
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 303?
Stainless 303 is stronger: its yield strength is 275 MPa against 33 MPa for Plastic Polypropylene (8.33x).
Which is lighter, Plastic Polypropylene or Stainless 303?
Plastic Polypropylene is lighter: 900 kg/m³ against 7,900 kg/m³ for Stainless 303.
Which is stiffer, Plastic Polypropylene or Stainless 303?
Stainless 303 is stiffer: Young's modulus 200 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in Stainless 303 deflects less under the same load.
Which is lighter for the same job, Plastic Polypropylene or Stainless 303?
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 303 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic Polypropylene | Stainless 303 |
|---|---|---|
| Stiff rod or tie (tension) | 15.7x heavier | lighter |
| Stiff beam (bending) | 34% heavier | lighter |
| Stiff panel or plate | lighter | 1.7x heavier |
| Strong rod or tie | lighter | 5% heavier |
| Strong beam | lighter | 2.14x heavier |
| Strong panel or plate | lighter | 3.04x 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 303?
Stainless 303 conducts heat better: 15 W/m·K against 0.195 W/m·K for Plastic Polypropylene.
Which expands less with temperature?
Stainless 303 expands less: 16 µm/m·K against 90 µm/m·K for Plastic Polypropylene.