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

Grade 20 cast iron is a type of grey cast iron. It is furnished 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). The length of each bar shows the given value as a % of the largest value in the relevant set.

## Mechanical Properties

Brinell Hardness

160

Compressive (Crushing) Strength

570 *MPa* 83 *x 10 ^{3} psi*

Elastic (Young's, Tensile) Modulus

180 *GPa* 26 *x 10 ^{6} psi*

Elongation at Break

0.52 *%*

Fatigue Strength

69 *MPa* 10 *x 10 ^{3} psi*

Fracture Toughness

10 *MPa-m ^{1/2}* 9.1

*x 10*

^{3}psi-in^{1/2}Poisson's Ratio

0.29

Shear Modulus

69 *GPa* 10 *x 10 ^{6} psi*

Shear Strength

180 *MPa* 26 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

160 *MPa* 23 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

98 *MPa* 14 *x 10 ^{3} psi*

## Thermal Properties

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*

## Otherwise Unclassified Properties

Base Metal Price

1.9 *% relative*

Density

7.5 *g/cm ^{3}* 470

*lb/ft*

^{3}Embodied Carbon

1.5 *kg CO _{2}/kg material*

Embodied Energy

21 *MJ/kg* 9.1 *x 10 ^{3} BTU/lb*

Embodied Water

44 *L/kg* 5.2 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

0.72 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

27 *kJ/m ^{3}*

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 *m ^{2}/s*

Thermal Shock Resistance

6.0 *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