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ASTM Grade 20 or 150 (ISO 150, EN-JL 1020, F11401) Grey Cast Iron

Grade 20 cast iron is grey cast iron in the as-fabricated (no temper or treatment) condition. Grade 20 is the ASTM designation for this material. 150 is the ISO numeric designation. And F11401 is the UNS number. It has the lowest strength compared to the other variants of grey cast iron.

The graph bars on the material properties cards below compare grade 20 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

Compressive (Crushing) Strength

570 MPa 83 x 103 psi

Elastic (Young's, Tensile) Modulus

180 GPa 26 x 106 psi

Elongation at Break

9.6 %

Fatigue Strength

69 MPa 10 x 103 psi

Fracture Toughness

10 MPa-m1/2 9.1 x 103 psi-in1/2

Poisson's Ratio

0.29

Shear Modulus

69 GPa 10 x 106 psi

Shear Strength

180 MPa 26 x 103 psi

Tensile Strength: Ultimate (UTS)

160 MPa 23 x 103 psi

Tensile Strength: Yield (Proof)

98 MPa 14 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 MJ/m3

Resilience: Unit (Modulus of Resilience)

27 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

5.8 points

Strength to Weight: Bending

8.7 points

Thermal Diffusivity

13 mm2/s

Thermal Shock Resistance

6.0 points

Alloy Composition

Iron (Fe)Fe 92.1 to 93.9
Carbon (C)C 3.1 to 3.4
Silicon (Si)Si 2.5 to 2.8
Manganese (Mn)Mn 0.5 to 0.7
Phosphorus (P)P 0 to 0.9
Sulfur (S)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