ACI-ASTM CN3MN (J94651) Cast Stainless Steel
ACI-ASTM CN3MN steel is an austenitic stainless steel formulated for casting. Cited properties are appropriate for the heat treated (HT) condition. CN3MN is the designation in both the ACI and ASTM systems for this material. J94651 is the UNS number.
It has a fairly high tensile strength among cast austenitic stainless steels. In addition, it has a fairly high embodied energy and a moderately high base cost.
The graph bars on the material properties cards below compare ACI-ASTM CN3MN 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
210 GPa 30 x 106 psi
Elongation at Break
39 %
Fatigue Strength
250 MPa 37 x 103 psi
Poisson's Ratio
0.28
Shear Modulus
80 GPa 12 x 106 psi
Tensile Strength: Ultimate (UTS)
620 MPa 89 x 103 psi
Tensile Strength: Yield (Proof)
300 MPa 43 x 103 psi
Thermal Properties
Latent Heat of Fusion
310 J/g
Maximum Temperature: Corrosion
430 °C 800 °F
Maximum Temperature: Mechanical
1100 °C 2010 °F
Melting Completion (Liquidus)
1460 °C 2650 °F
Melting Onset (Solidus)
1410 °C 2560 °F
Specific Heat Capacity
460 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
13 W/m-K 7.3 BTU/h-ft-°F
Thermal Expansion
16 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
1.8 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.0 % IACS
Otherwise Unclassified Properties
Base Metal Price
33 % relative
Density
8.1 g/cm3 500 lb/ft3
Embodied Carbon
6.2 kg CO2/kg material
Embodied Energy
84 MJ/kg 36 x 103 BTU/lb
Embodied Water
200 L/kg 24 gal/lb
Common Calculations
PREN (Pitting Resistance)
46
Resilience: Ultimate (Unit Rupture Work)
200 MJ/m3
Resilience: Unit (Modulus of Resilience)
210 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
21 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
3.4 mm2/s
Thermal Shock Resistance
14 points
Alloy Composition
Among cast stainless steels, the composition of ACI-ASTM CN3MN steel is notable for containing comparatively high amounts of nickel (Ni) and molybdenum (Mo). Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion. Molybdenum is used to facilitate tempering. In addition, it offers modest bonuses to a wide range of material properties.
| Fe | 41.4 to 50.3 | |
| Ni | 23.5 to 25.5 | |
| Cr | 20 to 22 | |
| Mo | 6.0 to 7.0 | |
| Mn | 0 to 2.0 | |
| Si | 0 to 1.0 | |
| Cu | 0 to 0.75 | |
| N | 0.18 to 0.26 | |
| P | 0 to 0.040 | |
| C | 0 to 0.030 | |
| S | 0 to 0.010 |
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