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328.0 (SC82A, A03280) Cast Aluminum

328.0 aluminum is an aluminum alloy formulated for casting. 328.0 is the Aluminum Association (AA) designation for this material. A03280 is the UNS number. Additionally, the SAE designation is 327. Older literature may refer to this material as ASTM SC82A or Red X-8.

The properties of 328.0 aluminum include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare 328.0 aluminum to: ANSI/AA cast aluminums (top), all aluminum alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Brinell Hardness

60 to 82

Elastic (Young's, Tensile) Modulus

72 GPa 10 x 106 psi

Elongation at Break

1.6 to 2.1 %

Fatigue Strength

55 to 80 MPa 8.0 to 12 x 103 psi

Poisson's Ratio


Shear Modulus

27 GPa 3.9 x 106 psi

Tensile Strength: Ultimate (UTS)

200 to 270 MPa 29 to 40 x 103 psi

Tensile Strength: Yield (Proof)

120 to 170 MPa 17 to 25 x 103 psi

Thermal Properties

Latent Heat of Fusion

510 J/g

Maximum Temperature: Mechanical

180 °C 350 °F

Melting Completion (Liquidus)

620 °C 1140 °F

Melting Onset (Solidus)

560 °C 1050 °F

Solidification (Pattern Maker's) Shrinkage

1.3 %

Specific Heat Capacity

890 J/kg-K 0.21 BTU/lb-°F

Thermal Conductivity

120 W/m-K 70 BTU/h-ft-°F

Thermal Expansion

22 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

30 % IACS

Electrical Conductivity: Equal Weight (Specific)

99 % IACS

Otherwise Unclassified Properties

Base Metal Price

10 % relative


2.7 g/cm3 170 lb/ft3

Embodied Carbon

7.8 kg CO2/kg material

Embodied Energy

140 MJ/kg 62 x 103 BTU/lb

Embodied Water

1070 L/kg 130 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

2.8 to 5.0 MJ/m3

Resilience: Unit (Modulus of Resilience)

92 to 200 kJ/m3

Stiffness to Weight: Axial

15 points

Stiffness to Weight: Bending

51 points

Strength to Weight: Axial

21 to 28 points

Strength to Weight: Bending

28 to 34 points

Thermal Diffusivity

50 mm2/s

Thermal Shock Resistance

9.2 to 12 points

Alloy Composition

Among cast aluminum alloys, the composition of 328.0 aluminum is notable for including chromium (Cr). Chromium is used to limit grain growth during hot working or heat treatment, which improves ductility and toughness. Chromium also reduces the alloy's susceptibility to stress corrosion cracking. If the alloy is anodized, the presence of chromium will tend to add a yellow tint to the film.

Aluminum (Al)Al 84.5 to 91.1
Silicon (Si)Si 7.5 to 8.5
Copper (Cu)Cu 1.0 to 2.0
Zinc (Zn)Zn 0 to 1.5
Iron (Fe)Fe 0 to 1.0
Manganese (Mn)Mn 0.2 to 0.6
Magnesium (Mg)Mg 0.2 to 0.6
Chromium (Cr)Cr 0 to 0.35
Nickel (Ni)Ni 0 to 0.25
Titanium (Ti)Ti 0 to 0.25
Residualsres. 0 to 0.5

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

ASTM B618: Standard Specification for Aluminum-Alloy Investment Castings

ASTM B26: Standard Specification for Aluminum-Alloy Sand Castings

Iron in Aluminium Alloys: Impurity and Alloying Element, N. A. Belov et al., 2002

Handbook of Aluminum Bonding Technology and Data, J. D. Minford, 1993