ACI-ASTM CB7Cu-2 (J92110) Cast Stainless Steel
ACI-ASTM CB7Cu-2 steel is a precipitation-hardening stainless steel formulated for casting. CB7Cu-2 is the designation in both the ACI and ASTM systems for this material. J92110 is the UNS number.
It can have a moderately low ductility among iron alloys. In addition, it has a moderately high heat capacity and a fairly low electrical conductivity.
The properties of ACI-ASTM CB7Cu-2 steel include six common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare ACI-ASTM CB7Cu-2 steel to: cast precipitation-hardening 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
300 to 420
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
5.7 to 11 %
Fatigue Strength
420 to 590 MPa 61 to 85 x 103 psi
Poisson's Ratio
0.28
Shear Modulus
75 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
960 to 1350 MPa 140 to 200 x 103 psi
Tensile Strength: Yield (Proof)
760 to 1180 MPa 110 to 170 x 103 psi
Thermal Properties
Latent Heat of Fusion
280 J/g
Melting Completion (Liquidus)
1430 °C 2600 °F
Melting Onset (Solidus)
1380 °C 2520 °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
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
2.1 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.4 % IACS
Otherwise Unclassified Properties
Base Metal Price
13 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
2.6 kg CO2/kg material
Embodied Energy
38 MJ/kg 16 x 103 BTU/lb
Embodied Water
130 L/kg 15 gal/lb
Common Calculations
PREN (Pitting Resistance)
15
Resilience: Ultimate (Unit Rupture Work)
71 to 120 MJ/m3
Resilience: Unit (Modulus of Resilience)
1510 to 3600 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
34 to 48 points
Strength to Weight: Bending
28 to 35 points
Thermal Diffusivity
4.6 mm2/s
Thermal Shock Resistance
32 to 45 points
Alloy Composition
Among cast stainless steels, the composition of ACI-ASTM CB7Cu-2 steel is notable for including niobium (Nb) and copper (Cu). Niobium is primarily used to improve yield strength, particularly at elevated temperatures. Copper is primarily used to improve resistance to acids.
| Fe | 73.6 to 79 | |
| Cr | 14 to 15.5 | |
| Ni | 4.5 to 5.5 | |
| Cu | 2.5 to 3.2 | |
| Si | 0 to 1.0 | |
| Mn | 0 to 0.7 | |
| Nb | 0 to 0.35 | |
| C | 0 to 0.070 | |
| N | 0 to 0.050 | |
| P | 0 to 0.035 | |
| S | 0 to 0.030 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A747: Standard Specification for Steel Castings, Stainless, Precipitation Hardening
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