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Automotive Grey Cast Iron

Automotive grey cast iron is a cast iron. It can have the lowest tensile strength among the cast irons in the database.

The properties of automotive grey cast iron include nine common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare automotive grey cast iron to: cast irons (top), all iron 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

160 to 280

Elastic (Young's, Tensile) Modulus

180 GPa 26 x 106 psi

Elongation at Break

9.6 to 14 %

Poisson's Ratio


Shear Modulus

69 to 70 GPa 10 x 106 psi

Tensile Strength: Ultimate (UTS)

140 to 290 MPa 20 to 43 x 103 psi

Tensile Strength: Yield (Proof)

94 to 200 MPa 14 to 30 x 103 psi

Thermal Properties

Latent Heat of Fusion

260 to 280 J/g

Melting Completion (Liquidus)

1380 to 1390 °C 2510 to 2540 °F

Melting Onset (Solidus)

1340 to 1350 °C 2440 to 2470 °F

Specific Heat Capacity

490 J/kg-K 0.12 BTU/lb-°F

Thermal Conductivity

41 to 43 W/m-K 24 to 25 BTU/h-ft-°F

Thermal Expansion

12 to 14 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.4 to 7.6 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.8 to 9.1 % IACS

Otherwise Unclassified Properties

Base Metal Price

1.9 to 3.0 % relative


7.5 to 7.6 g/cm3 470 lb/ft3

Embodied Carbon

1.5 to 1.7 kg CO2/kg material

Embodied Energy

21 to 24 MJ/kg 8.9 to 10 x 103 BTU/lb

Embodied Water

44 to 51 L/kg 5.2 to 6.1 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

18 to 25 MJ/m3

Resilience: Unit (Modulus of Resilience)

25 to 110 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

5.2 to 11 points

Strength to Weight: Bending

8.0 to 13 points

Thermal Diffusivity

11 to 12 mm2/s

Thermal Shock Resistance

4.2 to 8.6 points

Followup Questions

Further Reading

ASTM A159: Standard Specification for Automotive Gray Iron Castings

SAE J431: Automotive Gray Iron Castings

Cast Iron: Physical and Engineering Properties, Harold T. Angus, 1976

Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993

Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008