ASTM Grade 325 Grey Cast Iron
Grade 325 cast iron is grey cast iron in the as-fabricated (no temper or treatment) condition. The graph bars on the material properties cards below compare grade 325 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
230
Elastic (Young's, Tensile) Modulus
180 GPa 26 x 106 psi
Elongation at Break
9.6 %
Poisson's Ratio
0.29
Shear Modulus
69 GPa 10 x 106 psi
Tensile Strength: Ultimate (UTS)
370 MPa 54 x 103 psi
Tensile Strength: Yield (Proof)
260 MPa 37 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)
32 MJ/m3
Resilience: Unit (Modulus of Resilience)
180 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
14 points
Strength to Weight: Bending
15 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
14 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
Further Reading
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