Materials / Compare
Plastic HDPE vs. Stainless 303
Compare Plastic HDPE 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 | 24MPasourcetypical, tensile stress at yield 23 °C, 50 mm/min 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) | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 | 200GPasourceat RT (Table 12) |
| Density | 950kg/m³sourcetypical, ISO 1183 | 7,900kg/m³sourceat RT |
| Strength to weight | 25.3kN·m/kg | 34.8kN·m/kg38% higher |
| Stiffness to weight | 0.947MN·m/kg | 25.3MN·m/kg26.7x higher |
| Poisson's ratio | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 0.316GPa | 76.9GPa244x stiffer in shear |
| Bulk modulus | 2GPa | 167GPa |
| Speed of sound | 973m/s | 5,032m/s |
| Thermal | ||
| Thermal conductivity | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 15W/m·Ksourceat RT |
| Thermal expansion | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 16µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 600µm growth | 80µm growth7.5x less |
| Specific heat | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 500J/kg·Ksourceat RT |
| Heats up and cools (diffusivity) | 0.208mm²/s | 3.8mm²/s18.2x faster |
| Thermal shock resistance | 56.9W/m | 902W/m15.9x more resistant |
| Max service temperature | not sourced | 871°Csourcecontinuous, scaling limit |
| Values for | LyondellBasell Hostalen 23050 B high density polyethylene, 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 HDPE stronger than Stainless 303?
Stainless 303 is stronger: its yield strength is 275 MPa against 24 MPa for Plastic HDPE (11.5x).
Which is lighter, Plastic HDPE or Stainless 303?
Plastic HDPE is lighter: 950 kg/m³ against 7,900 kg/m³ for Stainless 303.
Which is stiffer, Plastic HDPE or Stainless 303?
Stainless 303 is stiffer: Young's modulus 200 GPa against 0.9 GPa for Plastic HDPE, so the same part in Stainless 303 deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Stainless 303?
For the same stiffness or strength: Plastic HDPE is lighter for a stiff panel or plate, strong beam, strong panel or plate; Stainless 303 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic HDPE | Stainless 303 |
|---|---|---|
| Stiff rod or tie (tension) | 26.7x heavier | lighter |
| Stiff beam (bending) | 1.79x heavier | lighter |
| Stiff panel or plate | lighter | 37% heavier |
| Strong rod or tie | 38% heavier | lighter |
| Strong beam | lighter | 1.64x heavier |
| Strong panel or plate | lighter | 2.46x 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 HDPE or Stainless 303?
Stainless 303 conducts heat better: 15 W/m·K against 0.445 W/m·K for Plastic HDPE.
Which expands less with temperature?
Stainless 303 expands less: 16 µm/m·K against 120 µm/m·K for Plastic HDPE.