Materials / Compare
Plastic PMMA vs. Stainless 304
Compare Plastic PMMA vs. Stainless 304 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 | not given (tensile used) | 241MPasourcetypical, annealed, 70 °F (21 °C) |
| Ultimate tensile strength | 80MPasourcetypical, 23 °C | 586MPasourcetypical, annealed, 70 °F (21 °C) |
| Compressive strength | 110MPasourcecompressive yield stress, typical | not sourced |
| Flexural strength | 115MPasourcetypical | not sourced |
| Elongation at break | 5.5%sourcetypical | 55%sourcetypical, annealed, in 2 in. (50.8 mm) |
| Young's modulus (stiffness) | 3.3GPasourcetypical, short-term | 193GPasourcetypical, in tension |
| Density | 1,190kg/m³sourcetypical6.75x lighter | 8,030kg/m³sourcetypical |
| Strength to weight | 67.2kN·m/kg2.24x higher | 30kN·m/kg |
| Stiffness to weight | 2.77MN·m/kg | 24MN·m/kg8.67x higher |
| Poisson's ratio | 0.37sourcetypical | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 1.2GPa | 74.2GPa61.6x stiffer in shear |
| Bulk modulus | 4.23GPa | 161GPa |
| Speed of sound | 1,665m/s | 4,903m/s |
| Thermal | ||
| Thermal conductivity | 0.19W/m·Ksourcetypical | 16.2W/m·Ksourceat 100 °C |
| Thermal expansion | 70µm/m·Ksource0-50 °C | 16.9µm/m·Ksourcemean, 0–100 °C |
| 100 mm part over a 50 °C swing | 350µm growth | 84.5µm growth4.14x less |
| Specific heat | 1,470J/kg·Ksourcetypical | 500J/kg·Ksourcemean, 0–100 °C |
| Heats up and cools (diffusivity) | 0.109mm²/s | 4.03mm²/s37.1x faster |
| Thermal shock resistance | 41.5W/m | 838W/m20.2x more resistant |
| Melting point | not sourced | 1,399–1,454°Csourcemelting range |
| Max service temperature | 80°Csourcemax. permanent service temperature | 899°Csourcecontinuous, oxidation (scaling) limit in air |
| Values for | Röhm PLEXIGLAS GS 0F00 cast acrylic sheet, typical values at 23 °C / 50 % RH (Röhm Technical Information Ref. No. 211-1) | Type 304, annealed flat-rolled (Cleveland-Cliffs 304/304L Product Data Bulletin, May 2021); Poisson's ratio from the Nickel Institute/SCI structural stainless design manual |
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 PMMA stronger than Stainless 304?
Stainless 304 is stronger: its yield strength is 241 MPa against tensile strength 80 MPa for Plastic PMMA (3.01x).
Which is lighter, Plastic PMMA or Stainless 304?
Plastic PMMA is lighter: 1,190 kg/m³ against 8,030 kg/m³ for Stainless 304.
Which is stiffer, Plastic PMMA or Stainless 304?
Stainless 304 is stiffer: Young's modulus 193 GPa against 3.3 GPa for Plastic PMMA, so the same part in Stainless 304 deflects less under the same load.
Which is lighter for the same job, Plastic PMMA or Stainless 304?
For the same stiffness or strength: Plastic PMMA is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Stainless 304 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic PMMA | Stainless 304 |
|---|---|---|
| Stiff rod or tie (tension) | 8.67x heavier | lighter |
| Stiff beam (bending) | 13% heavier | lighter |
| Stiff panel or plate | lighter | 1.74x heavier |
| Strong rod or tie | lighter | 2.24x heavier |
| Strong beam | lighter | 3.24x heavier |
| Strong panel or plate | lighter | 3.89x 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 PMMA or Stainless 304?
Stainless 304 conducts heat better: 16.2 W/m·K against 0.19 W/m·K for Plastic PMMA.
Which expands less with temperature?
Stainless 304 expands less: 16.9 µm/m·K against 70 µm/m·K for Plastic PMMA.