Materials / Compare
Steel AISI 4340 vs. Zinc Zamak 3
Compare Steel AISI 4340 vs. Zinc Zamak 3 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 | 1,035MPasourcetypical, transverse | 221MPasourcetypical |
| Ultimate tensile strength | 1,140MPasourcetypical, transverse | 283MPasourcetypical |
| Elongation at break | 18%sourcetypical, transverse | 10%sourcetypical, in 2 in. |
| Young's modulus (stiffness) | 200GPasourceMIL-HDBK-5J design value (AISI 4340, quenched and tempered) | 85.5GPasourcetypical |
| Density | 7,840kg/m³sourcetypical | 6,600kg/m³sourcetypical19% lighter |
| Strength to weight | 132kN·m/kg3.94x higher | 33.5kN·m/kg |
| Stiffness to weight | 25.5MN·m/kg1.97x higher | 13MN·m/kg |
| Poisson's ratio | 0.32sourceMIL-HDBK-5J design value (AISI 4340, quenched and tempered) | 0.27sourcetypical, Zamak 3 hot-chamber die cast |
| Shear modulus | 75.7GPa2.25x stiffer in shear | 33.7GPa |
| Bulk modulus | 185GPa | 62GPa |
| Speed of sound | 5,049m/s | 3,599m/s |
| Thermal | ||
| Thermal conductivity | 37.5W/m·Ksourcetypical | 113W/m·Ksourcetypical3.01x more heat through a fin |
| Thermal expansion | 11.3µm/m·Ksourcemean, -18 to 93 °C | 27.4µm/m·Ksourcetypical |
| 100 mm part over a 50 °C swing | 56.5µm growth2.42x less | 137µm growth |
| Specific heat | 448J/kg·Ksourcetypical | 419J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 10.7mm²/s | 40.9mm²/s3.83x faster |
| Thermal shock resistance | 11,678W/m1.5x more resistant | 7,782W/m |
| Melting point | not sourced | 381–387°Csourcemelting range |
| Values for | Carpenter (Latrobe) Lescalloy 4340 VAC-ARC datasheet; mechanical row for 1100 °F temper; physical properties grade-level | Zamak 3 (ASTM B86 die cast), Nathan Trotter (zinc alloy producer) technical data sheet, typical values |
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 Steel AISI 4340 stronger than Zinc Zamak 3?
Steel AISI 4340 is stronger: its yield strength is 1,035 MPa against 221 MPa for Zinc Zamak 3 (4.68x).
Which is lighter, Steel AISI 4340 or Zinc Zamak 3?
Zinc Zamak 3 is lighter: 6,600 kg/m³ against 7,840 kg/m³ for Steel AISI 4340.
Which is stiffer, Steel AISI 4340 or Zinc Zamak 3?
Steel AISI 4340 is stiffer: Young's modulus 200 GPa against 85.5 GPa for Zinc Zamak 3, so the same part in Steel AISI 4340 deflects less under the same load.
Which is lighter for the same job, Steel AISI 4340 or Zinc Zamak 3?
For the same stiffness or strength: Steel AISI 4340 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Steel AISI 4340 | Zinc Zamak 3 |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 1.97x heavier |
| Stiff beam (bending) | lighter | 29% heavier |
| Stiff panel or plate | lighter | 12% heavier |
| Strong rod or tie | lighter | 3.94x heavier |
| Strong beam | lighter | 2.36x heavier |
| Strong panel or plate | lighter | 1.82x 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, Steel AISI 4340 or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 37.5 W/m·K for Steel AISI 4340.
Which expands less with temperature?
Steel AISI 4340 expands less: 11.3 µm/m·K against 27.4 µm/m·K for Zinc Zamak 3.