MakeItFrom.com
Menu (ESC)

ACI-ASTM CG8M (J93000) Cast Stainless Steel

ACI-ASTM CG8M steel is an austenitic stainless steel formulated for casting. Cited properties are appropriate for the heat treated (HT) condition. CG8M is the designation in both the ACI and ASTM systems for this material. J93000 is the UNS number.

It has a moderately high thermal conductivity among cast austenitic stainless steels. In addition, it has a fairly high ductility and a moderately high tensile strength.

The graph bars on the material properties cards below compare ACI-ASTM CG8M steel to: cast austenitic 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

180

Elastic (Young's, Tensile) Modulus

200 GPa 29 x 106 psi

Elongation at Break

45 %

Fatigue Strength

280 MPa 40 x 103 psi

Impact Strength: V-Notched Charpy

110 J 81 ft-lb

Poisson's Ratio

0.28

Shear Modulus

79 GPa 11 x 106 psi

Tensile Strength: Ultimate (UTS)

550 MPa 80 x 103 psi

Tensile Strength: Yield (Proof)

300 MPa 44 x 103 psi

Thermal Properties

Latent Heat of Fusion

300 J/g

Maximum Temperature: Corrosion

420 °C 790 °F

Maximum Temperature: Mechanical

1020 °C 1860 °F

Melting Completion (Liquidus)

1450 °C 2640 °F

Melting Onset (Solidus)

1400 °C 2550 °F

Specific Heat Capacity

470 J/kg-K 0.11 BTU/lb-°F

Thermal Conductivity

16 W/m-K 9.3 BTU/h-ft-°F

Thermal Expansion

16 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

2.0 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.3 % IACS

Otherwise Unclassified Properties

Base Metal Price

20 % relative

Density

7.9 g/cm3 490 lb/ft3

Embodied Carbon

4.1 kg CO2/kg material

Embodied Energy

56 MJ/kg 24 x 103 BTU/lb

Embodied Water

160 L/kg 19 gal/lb

Common Calculations

PREN (Pitting Resistance)

31

Resilience: Ultimate (Unit Rupture Work)

210 MJ/m3

Resilience: Unit (Modulus of Resilience)

220 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

25 points

Strength to Weight: Axial

19 points

Strength to Weight: Bending

19 points

Thermal Diffusivity

4.3 mm2/s

Thermal Shock Resistance

12 points

Alloy Composition

Among cast stainless steels, the composition of ACI-ASTM CG8M steel is notable for containing a comparatively high amount of molybdenum (Mo). Molybdenum is used to facilitate tempering. In addition, it offers modest bonuses to a wide range of material properties.

Iron (Fe) 58.8 to 70
Chromium (Cr) 18 to 21
Nickel (Ni) 9.0 to 13
Molybdenum (Mo) 3.0 to 4.0
Manganese (Mn) 0 to 1.5
Silicon (Si) 0 to 1.5
Carbon (C) 0 to 0.080
Phosphorus (P) 0 to 0.040
Sulfur (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 Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002

Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984

ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994

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

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015