Materials / Compare
Plastic PMMA vs. Stainless 303
Compare Plastic PMMA 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 | not given (tensile used) | 275MPasourceOutokumpu typical (product P = hot rolled plate, transverse) |
| Ultimate tensile strength | 80MPasourcetypical, 23 °C | 585MPasourceOutokumpu typical |
| Compressive strength | 110MPasourcecompressive yield stress, typical | not sourced |
| Flexural strength | 115MPasourcetypical | not sourced |
| Elongation at break | 5.5%sourcetypical | 35%sourceOutokumpu typical, A5 |
| Young's modulus (stiffness) | 3.3GPasourcetypical, short-term | 200GPasourceat RT (Table 12) |
| Density | 1,190kg/m³sourcetypical | 7,900kg/m³sourceat RT |
| Strength to weight | 67.2kN·m/kg1.93x higher | 34.8kN·m/kg |
| Stiffness to weight | 2.77MN·m/kg | 25.3MN·m/kg9.13x higher |
| Poisson's ratio | 0.37sourcetypical | 0.3sourcedesign value (structural stainless steels) |
| Shear modulus | 1.2GPa | 76.9GPa63.9x stiffer in shear |
| Bulk modulus | 4.23GPa | 167GPa |
| Speed of sound | 1,665m/s | 5,032m/s |
| Thermal | ||
| Thermal conductivity | 0.19W/m·Ksourcetypical | 15W/m·Ksourceat RT |
| Thermal expansion | 70µm/m·Ksource0-50 °C | 16µm/m·Ksourcemean, 20–100 °C |
| 100 mm part over a 50 °C swing | 350µm growth | 80µm growth4.38x less |
| Specific heat | 1,470J/kg·Ksourcetypical | 500J/kg·Ksourceat RT |
| Heats up and cools (diffusivity) | 0.109mm²/s | 3.8mm²/s35x faster |
| Thermal shock resistance | 41.5W/m | 902W/m21.8x more resistant |
| Max service temperature | 80°Csourcemax. permanent service temperature | 871°Csourcecontinuous, scaling limit |
| Values for | Röhm PLEXIGLAS GS 0F00 cast acrylic sheet, typical values at 23 °C / 50 % RH (Röhm Technical Information Ref. No. 211-1) | 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 PMMA stronger than Stainless 303?
Stainless 303 is stronger: its yield strength is 275 MPa against tensile strength 80 MPa for Plastic PMMA (3.44x).
Which is lighter, Plastic PMMA or Stainless 303?
Plastic PMMA is lighter: 1,190 kg/m³ against 7,900 kg/m³ for Stainless 303.
Which is stiffer, Plastic PMMA or Stainless 303?
Stainless 303 is stiffer: Young's modulus 200 GPa against 3.3 GPa for Plastic PMMA, so the same part in Stainless 303 deflects less under the same load.
Which is lighter for the same job, Plastic PMMA or Stainless 303?
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 303 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic PMMA | Stainless 303 |
|---|---|---|
| Stiff rod or tie (tension) | 9.13x heavier | lighter |
| Stiff beam (bending) | 17% heavier | lighter |
| Stiff panel or plate | lighter | 1.69x heavier |
| Strong rod or tie | lighter | 1.93x heavier |
| Strong beam | lighter | 2.91x heavier |
| Strong panel or plate | lighter | 3.58x 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 303?
Stainless 303 conducts heat better: 15 W/m·K against 0.19 W/m·K for Plastic PMMA.
Which expands less with temperature?
Stainless 303 expands less: 16 µm/m·K against 70 µm/m·K for Plastic PMMA.