AISI 1045 cold drawn bar (Niagara LaSalle) for mechanical; Ovako C45 (lists 'SAE 1045' as a similar designation) for physical constants
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 1045 stronger than Zinc Zamak 3?
Steel AISI 1045 is stronger: its yield strength is 531 MPa against 221 MPa for Zinc Zamak 3 (2.4x).
Which is lighter, Steel AISI 1045 or Zinc Zamak 3?
Zinc Zamak 3 is lighter: 6,600 kg/m³ against 7,800 kg/m³ for Steel AISI 1045.
Which is stiffer, Steel AISI 1045 or Zinc Zamak 3?
Steel AISI 1045 is stiffer: Young's modulus 210 GPa against 85.5 GPa for Zinc Zamak 3, so the same part in Steel AISI 1045 deflects less under the same load.
Which is lighter for the same job, Steel AISI 1045 or Zinc Zamak 3?
For the same stiffness or strength: Steel AISI 1045 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 1045
Zinc Zamak 3
Stiff rod or tie (tension)
lighter
2.08x heavier
Stiff beam (bending)
lighter
33% heavier
Stiff panel or plate
lighter
14% heavier
Strong rod or tie
lighter
2.03x heavier
Strong beam
lighter
1.52x heavier
Strong panel or plate
lighter
31% 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 1045 or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 42.5 W/m·K for Steel AISI 1045.
Which expands less with temperature?
Steel AISI 1045 expands less: 12 µm/m·K against 27.4 µm/m·K for Zinc Zamak 3.