# ACI-ASTM CA40 (SCS2A, J91153) Cast Stainless Steel

ACI-ASTM CA40 steel is a martensitic stainless steel formulated for casting. It is typically furnished in the heat treated (HT) condition. CA40 is the designation in both the ACI and ASTM systems for this material. J91153 is the UNS number.

It has a fairly low base cost among cast martensitic stainless steels. In addition, it has the lowest ductility and a moderately low embodied energy.

The graph bars on the material properties cards below compare ACI-ASTM CA40 steel to: cast martensitic stainless steels (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

310

Elastic (Young's, Tensile) Modulus

190 *GPa* 28 *x 10 ^{6} psi*

Elongation at Break

10 *%*

Fatigue Strength

460 *MPa* 66 *x 10 ^{3} psi*

Poisson's Ratio

0.28

Shear Modulus

76 *GPa* 11 *x 10 ^{6} psi*

Tensile Strength: Ultimate (UTS)

910 *MPa* 130 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

860 *MPa* 120 *x 10 ^{3} psi*

## Thermal Properties

Melting Onset (Solidus)

1500 *°C* 2730 *°F*

Specific Heat Capacity

480 *J/kg-K* 0.11 *BTU/lb-°F*

Thermal Conductivity

25 *W/m-K* 14 *BTU/h-ft-°F*

Thermal Expansion

10 *µm/m-K*

## Electrical Properties

Electrical Conductivity: Equal Volume

3.0 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

3.5 *% IACS*

## Otherwise Unclassified Properties

Base Metal Price

7.4 *% relative*

Density

7.7 *g/cm ^{3}* 480

*lb/ft*

^{3}Embodied Carbon

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

Embodied Energy

28 *MJ/kg* 12 *x 10 ^{3} BTU/lb*

Embodied Water

100 *L/kg* 12 *gal/lb*

## Common Calculations

PREN (Pitting Resistance)

14

Resilience: Ultimate (Unit Rupture Work)

89 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

1910 *kJ/m ^{3}*

Stiffness to Weight: Axial

14 *points*

Stiffness to Weight: Bending

25 *points*

Strength to Weight: Axial

33 *points*

Strength to Weight: Bending

27 *points*

Thermal Diffusivity

6.7 *m ^{2}/s*

Thermal Shock Resistance

33 *points*

## Alloy Composition

Fe | 81.5 to 88.3 | |

Cr | 11.5 to 14 | |

Si | 0 to 1.5 | |

Mn | 0 to 1.0 | |

Ni | 0 to 1.0 | |

C | 0.2 to 0.4 | |

Mo | 0 to 0.5 | |

P | 0 to 0.040 | |

S | 0 to 0.040 |

All values are % weight. Ranges represent what is permitted under applicable standards.

## Followup Questions

## Similar Alloys

## Further Reading

ASTM A743: Standard Specification for Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application

Advances in Stainless Steels, Raj et al. (editors), 2010

Welding Metallurgy and Weldability of Stainless Steels, John C. Lippold and Damian J. Kotecki, 2005

Corrosion of Stainless Steels, A. John Sedriks, 1996