ASTM Grade 35 or 250 (ISO 250, EN-JL 1040, F12401) Grey Cast Iron
Grade 35 cast iron is grey cast iron in the as-fabricated (no temper or treatment) condition. Grade 35 is the ASTM designation for this material. 250 is the ISO numeric designation. And F12401 is the UNS number. The graph bars on the material properties cards below compare grade 35 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
180
Compressive (Crushing) Strength
860 MPa 120 x 103 psi
Elastic (Young's, Tensile) Modulus
180 GPa 26 x 106 psi
Elongation at Break
9.6 %
Fatigue Strength
110 MPa 16 x 103 psi
Fracture Toughness
15 MPa-m1/2 14 x 103 psi-in1/2
Poisson's Ratio
0.29
Shear Modulus
69 GPa 10 x 106 psi
Shear Strength
330 MPa 48 x 103 psi
Tensile Strength: Ultimate (UTS)
250 MPa 36 x 103 psi
Tensile Strength: Yield (Proof)
170 MPa 24 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)
21 MJ/m3
Resilience: Unit (Modulus of Resilience)
76 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
9.2 points
Strength to Weight: Bending
12 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
9.5 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
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