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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.

Iron (Fe)Fe 73.6 to 79
Chromium (Cr)Cr 14 to 15.5
Nickel (Ni)Ni 4.5 to 5.5
Copper (Cu)Cu 2.5 to 3.2
Silicon (Si)Si 0 to 1.0
Manganese (Mn)Mn 0 to 0.7
Niobium (Nb)Nb 0 to 0.35
Carbon (C)C 0 to 0.070
Nitrogen (N)N 0 to 0.050
Phosphorus (P)P 0 to 0.035
Sulfur (S)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