ACI-ASTM CB6 (J91804) Cast Stainless Steel
ACI-ASTM CB6 steel is a martensitic stainless steel formulated for casting. Cited properties are appropriate for the heat treated (HT) condition. CB6 is the designation in both the ACI and ASTM systems for this material. J91804 is the UNS number.
It has a moderately low electrical conductivity among cast martensitic stainless steels. In addition, it has a moderately low thermal conductivity and a fairly high ductility.
The graph bars on the material properties cards below compare ACI-ASTM CB6 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
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Elongation at Break
18 %
Fatigue Strength
410 MPa 59 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
40 %
Shear Modulus
77 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
880 MPa 130 x 103 psi
Tensile Strength: Yield (Proof)
660 MPa 96 x 103 psi
Thermal Properties
Latent Heat of Fusion
280 J/g
Maximum Temperature: Corrosion
410 °C 770 °F
Maximum Temperature: Mechanical
870 °C 1600 °F
Melting Completion (Liquidus)
1440 °C 2620 °F
Melting Onset (Solidus)
1390 °C 2540 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
17 W/m-K 9.8 BTU/h-ft-°F
Thermal Expansion
10 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.6 % IACS
Otherwise Unclassified Properties
Base Metal Price
12 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
2.5 kg CO2/kg material
Embodied Energy
36 MJ/kg 15 x 103 BTU/lb
Embodied Water
130 L/kg 15 gal/lb
Common Calculations
PREN (Pitting Resistance)
17
Resilience: Ultimate (Unit Rupture Work)
150 MJ/m3
Resilience: Unit (Modulus of Resilience)
1110 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
32 points
Strength to Weight: Bending
26 points
Thermal Diffusivity
4.6 mm2/s
Thermal Shock Resistance
31 points
Alloy Composition
Among cast stainless steels, the composition of ACI-ASTM CB6 steel is notable for containing comparatively high amounts of chromium (Cr) and nickel (Ni). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion.
| Fe | 74.4 to 81 | |
| Cr | 15.5 to 17.5 | |
| Ni | 3.5 to 5.5 | |
| Mn | 0 to 1.0 | |
| Si | 0 to 1.0 | |
| Mo | 0 to 0.5 | |
| C | 0 to 0.060 | |
| P | 0 to 0.040 | |
| S | 0 to 0.030 |
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 of Stainless Steels, Erich Folkhard et al., 2012
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