Materials / Compare
Plastic POM/Acetal vs. Steel AISI 1018
Compare Plastic POM/Acetal vs. Steel AISI 1018 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) | 372MPasourceproducer-stated, cold drawn |
| Ultimate tensile strength | 69MPasourcetypical | 441MPasourceproducer-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 | 15%sourcein 2 in (50.8 mm) |
| Young's modulus (stiffness) | 2.8GPasourcetypical | 200GPasourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Density | 1,420kg/m³sourcetypical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties') | 7,861kg/m³sourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Strength to weight | 48.6kN·m/kg3% higher | 47.3kN·m/kg |
| Stiffness to weight | 1.97MN·m/kg | 25.4MN·m/kg12.9x higher |
| Poisson's ratio | 0.35sourcetypical | 0.32sourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Shear modulus | 1.04GPa | 75.7GPa73x stiffer in shear |
| Bulk modulus | 3.11GPa | 185GPa |
| Speed of sound | 1,404m/s | 5,043m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical | 51.9W/m·Ksourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Thermal expansion | 122µm/m·Ksourcemean, 29 to 60 °C | 12µm/m·Ksourcebase material: unalloyed carbon steel, Ovako family table (S275JR, 'none alloyed structural steels', C <= 0.21%); 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) | 486J/kg·Ksourcebase material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018) |
| Heats up and cools (diffusivity) | 0.192mm²/s | 13.6mm²/s70.7x faster |
| Thermal shock resistance | 52.5W/m | 5,473W/m104x 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 1018 cold drawn bar (Niagara LaSalle, cold-finished bar producer) |
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 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 69 MPa for Plastic POM/Acetal (5.39x).
Which is lighter, Plastic POM/Acetal or Steel AISI 1018?
Plastic POM/Acetal is lighter: 1,420 kg/m³ against 7,861 kg/m³ for Steel AISI 1018.
Which is stiffer, Plastic POM/Acetal or Steel AISI 1018?
Steel AISI 1018 is stiffer: Young's modulus 200 GPa against 2.8 GPa for Plastic POM/Acetal, so the same part in Steel AISI 1018 deflects less under the same load.
Which is lighter for the same job, Plastic POM/Acetal or Steel AISI 1018?
For the same stiffness or strength: Plastic POM/Acetal is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Steel AISI 1018 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic POM/Acetal | Steel AISI 1018 |
|---|---|---|
| Stiff rod or tie (tension) | 12.9x heavier | lighter |
| Stiff beam (bending) | 1.53x heavier | lighter |
| Stiff panel or plate | lighter | 33% heavier |
| Strong rod or tie | lighter | 3% heavier |
| Strong beam | lighter | 1.8x heavier |
| Strong panel or plate | lighter | 2.38x 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 1018?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 0.4 W/m·K for Plastic POM/Acetal.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 122 µm/m·K for Plastic POM/Acetal.