Materials / Compare
Plastic POM/Acetal vs. Steel AISI 1045
Compare Plastic POM/Acetal 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 | 69MPasourcetypical (single ASTM D638 tensile strength) | 531MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 69MPasourcetypical | 627MPasourceproducer-stated, cold drawn |
| Compressive strength | 124MPasourcecompressive stress at 10% deformation | not sourced |
| Flexural strength | 99MPasourceflexural yield strength, typical | not sourced |
| Elongation at break | 75%sourcetypical | 12%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 2.8GPasourcetypical | 210GPasourcetypical75x stiffer |
| Density | 1,420kg/m³sourcetypical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties') | 7,800kg/m³sourcetypical |
| Strength to weight | 48.6kN·m/kg | 68.1kN·m/kg40% higher |
| Stiffness to weight | 1.97MN·m/kg | 26.9MN·m/kg13.7x higher |
| Poisson's ratio | 0.35sourcetypical | 0.3sourcetypical |
| Shear modulus | 1.04GPa | 80.8GPa77.9x stiffer in shear |
| Bulk modulus | 3.11GPa | 175GPa |
| Speed of sound | 1,404m/s | 5,189m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical | 40–45W/m·Ksourcetypical range, ambient |
| Thermal expansion | 122µm/m·Ksourcemean, 29 to 60 °C | 12µm/m·Ksourcetypical, mean 20-300 °C |
| 100 mm part over a 50 °C swing | 610µm growth | 60µm growth10.2x less |
| Specific heat | 1,465J/kg·Ksourceaverage -18 to 100 °C, Delrin acetal resins (not grade-specific) | 460–480J/kg·Ksourcetypical range, 50/100 °C |
| Heats up and cools (diffusivity) | 0.192mm²/s | 11.6mm²/s60.3x faster |
| Thermal shock resistance | 52.5W/m | 6,269W/m119x more resistant |
| Melting point | 175°Csourcecrystalline melting point | not sourced |
| Max service temperature | 125°CsourceHDT 1.8 MPa (annealed) | not sourced |
| Values for | DuPont Delrin 100 acetal homopolymer, Table 2 'Typical Properties of Delrin Acetal Resins' (ASTM methods), Delrin Design Guide Module III hosted on delrin.com | 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 POM/Acetal stronger than Steel AISI 1045?
Steel AISI 1045 is stronger: its yield strength is 531 MPa against 69 MPa for Plastic POM/Acetal (7.7x).
Which is lighter, Plastic POM/Acetal or Steel AISI 1045?
Plastic POM/Acetal is lighter: 1,420 kg/m³ against 7,800 kg/m³ for Steel AISI 1045.
Which is stiffer, Plastic POM/Acetal or Steel AISI 1045?
Steel AISI 1045 is stiffer: Young's modulus 210 GPa against 2.8 GPa for Plastic POM/Acetal, so the same part in Steel AISI 1045 deflects less under the same load.
Which is lighter for the same job, Plastic POM/Acetal or Steel AISI 1045?
For the same stiffness or strength: Plastic POM/Acetal 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 POM/Acetal | Steel AISI 1045 |
|---|---|---|
| Stiff rod or tie (tension) | 13.7x heavier | lighter |
| Stiff beam (bending) | 1.58x heavier | lighter |
| Stiff panel or plate | lighter | 30% heavier |
| Strong rod or tie | 40% heavier | lighter |
| Strong beam | lighter | 41% heavier |
| Strong panel or plate | lighter | 1.98x 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 POM/Acetal or Steel AISI 1045?
Steel AISI 1045 conducts heat better: 42.5 W/m·K against 0.4 W/m·K for Plastic POM/Acetal.
Which expands less with temperature?
Steel AISI 1045 expands less: 12 µm/m·K against 122 µm/m·K for Plastic POM/Acetal.