ACI-ASTM CA40 (SCS2A, J91153) Cast Stainless Steel
ACI-ASTM CA40 steel is a martensitic stainless steel formulated for casting. Cited properties are appropriate for 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 moderately low embodied energy among cast martensitic stainless steels. In addition, it has a moderately low base cost and a moderately high electrical conductivity.
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). 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
310
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
10 %
Fatigue Strength
460 MPa 66 x 103 psi
Poisson's Ratio
0.28
Shear Modulus
76 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
910 MPa 130 x 103 psi
Tensile Strength: Yield (Proof)
860 MPa 120 x 103 psi
Thermal Properties
Latent Heat of Fusion
280 J/g
Maximum Temperature: Corrosion
390 °C 730 °F
Maximum Temperature: Mechanical
750 °C 1390 °F
Melting Completion (Liquidus)
1440 °C 2620 °F
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
7.5 % relative
Density
7.7 g/cm3 480 lb/ft3
Embodied Carbon
2.0 kg CO2/kg material
Embodied Energy
28 MJ/kg 12 x 103 BTU/lb
Embodied Water
100 L/kg 12 gal/lb
Common Calculations
PREN (Pitting Resistance)
14
Resilience: Ultimate (Unit Rupture Work)
89 MJ/m3
Resilience: Unit (Modulus of Resilience)
1910 kJ/m3
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 mm2/s
Thermal Shock Resistance
33 points
Alloy Composition
Among cast stainless steels, the composition of ACI-ASTM CA40 steel is notable for containing comparatively high amounts of chromium (Cr) and silicon (Si). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Silicon content is typically governed by metallurgical processing concerns, but it can also be added for the purpose of improving oxidation resistance.
| 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
Welding Metallurgy and Weldability of Stainless Steels, John C. Lippold and Damian J. Kotecki, 2005
Corrosion of Stainless Steels, A. John Sedriks, 1996
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010