Materials / Compare
Plastic HDPE vs. Steel AISI 1045
Compare Plastic HDPE vs. Steel AISI 1045 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 | 531MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | not sourced | 627MPasourceproducer-stated, cold drawn |
| Elongation at break | not sourced | 12%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 | 210GPasourcetypical |
| Density | 950kg/m³sourcetypical, ISO 1183 | 7,800kg/m³sourcetypical |
| Strength to weight | 25.3kN·m/kg | 68.1kN·m/kg2.69x higher |
| Stiffness to weight | 0.947MN·m/kg | 26.9MN·m/kg28.4x higher |
| Poisson's ratio | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.3sourcetypical |
| Shear modulus | 0.316GPa | 80.8GPa256x stiffer in shear |
| Bulk modulus | 2GPa | 175GPa |
| Speed of sound | 973m/s | 5,189m/s |
| Thermal | ||
| Thermal conductivity | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 40–45W/m·Ksourcetypical range, ambient |
| Thermal expansion | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 12µm/m·Ksourcetypical, mean 20-300 °C |
| 100 mm part over a 50 °C swing | 600µm growth | 60µm growth10x less |
| Specific heat | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 460–480J/kg·Ksourcetypical range, 50/100 °C |
| Heats up and cools (diffusivity) | 0.208mm²/s | 11.6mm²/s55.7x faster |
| Thermal shock resistance | 56.9W/m | 6,269W/m110x more resistant |
| Values for | LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values | AISI 1045 cold drawn bar (Niagara LaSalle) for mechanical; Ovako C45 (lists 'SAE 1045' as a similar designation) for physical constants |
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 Steel AISI 1045?
Steel AISI 1045 is stronger: its yield strength is 531 MPa against 24 MPa for Plastic HDPE (22.1x).
Which is lighter, Plastic HDPE or Steel AISI 1045?
Plastic HDPE is lighter: 950 kg/m³ against 7,800 kg/m³ for Steel AISI 1045.
Which is stiffer, Plastic HDPE or Steel AISI 1045?
Steel AISI 1045 is stiffer: Young's modulus 210 GPa against 0.9 GPa for Plastic HDPE, so the same part in Steel AISI 1045 deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Steel AISI 1045?
For the same stiffness or strength: Plastic HDPE is lighter for a stiff panel or plate, strong beam, strong panel or plate; Steel AISI 1045 is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie.
| Part that must be | Plastic HDPE | Steel AISI 1045 |
|---|---|---|
| Stiff rod or tie (tension) | 28.4x heavier | lighter |
| Stiff beam (bending) | 1.86x heavier | lighter |
| Stiff panel or plate | lighter | 33% heavier |
| Strong rod or tie | 2.69x heavier | lighter |
| Strong beam | lighter | 4% heavier |
| Strong panel or plate | lighter | 1.75x 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 Steel AISI 1045?
Steel AISI 1045 conducts heat better: 42.5 W/m·K against 0.445 W/m·K for Plastic HDPE.
Which expands less with temperature?
Steel AISI 1045 expands less: 12 µm/m·K against 120 µm/m·K for Plastic HDPE.