Grey Cast Iron
Grey cast iron is a cast iron. It has the highest thermal conductivity among the cast irons in the database.
The properties of grey cast iron include eleven 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 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 300
Compressive (Crushing) Strength
570 to 1290 MPa 83 to 190 x 103 psi
Elastic (Young's, Tensile) Modulus
180 GPa 26 x 106 psi
Elongation at Break
9.6 %
Fatigue Strength
69 to 170 MPa 10 to 25 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
69 GPa 10 x 106 psi
Shear Strength
180 to 610 MPa 26 to 88 x 103 psi
Tensile Strength: Ultimate (UTS)
160 to 450 MPa 23 to 65 x 103 psi
Tensile Strength: Yield (Proof)
98 to 290 MPa 14 to 43 x 103 psi
Thermal Properties
Latent Heat of Fusion
280 J/g
Melting Completion (Liquidus)
1380 °C 2510 °F
Melting Onset (Solidus)
1180 °C 2150 °F
Specific Heat Capacity
490 J/kg-K 0.12 BTU/lb-°F
Thermal Conductivity
46 W/m-K 27 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.4 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.9 % IACS
Otherwise Unclassified Properties
Base Metal Price
1.9 % relative
Density
7.5 g/cm3 470 lb/ft3
Embodied Carbon
1.5 kg CO2/kg material
Embodied Energy
21 MJ/kg 9.1 x 103 BTU/lb
Embodied Water
44 L/kg 5.2 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
13 to 37 MJ/m3
Resilience: Unit (Modulus of Resilience)
27 to 240 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
5.8 to 17 points
Strength to Weight: Bending
8.7 to 17 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
6.0 to 17 points
Alloy Composition
| Fe | 92.1 to 93.9 | |
| C | 3.1 to 3.4 | |
| Si | 2.5 to 2.8 | |
| Mn | 0.5 to 0.7 | |
| P | 0 to 0.9 | |
| S | 0 to 0.15 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ISO 185: Grey Cast Irons - Classification
ASTM A48: Standard Specification for Gray Iron Castings
Cast Iron: Physical and Engineering Properties, Harold T. Angus, 1976
Microstructure of Steels and Cast Irons, Madeleine Durand-Charre, 2004
Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015