ASTM F15 (1.3981, K94610) Fe-Ni-Co Sealing Alloy
ASTM F15 Fe-Ni-Co is an iron alloy formulated for controlled thermal expansion. ASTM F15 is the defining standard for this material. K94610 is the UNS number. Additionally, the EN chemical designation is FeNi28Co18Mn. And the AFNOR (French) designation is A54-301.
It has the highest base cost among low-expansion iron alloys. In addition, it has the highest electrical conductivity and can have the highest tensile strength.
The properties of ASTM F15 Fe-Ni-Co include five 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 ASTM F15 Fe-Ni-Co to: low-expansion iron alloys (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
190 GPa 28 x 106 psi
Poisson's Ratio
0.3
Shear Modulus
73 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
520 to 880 MPa 75 to 130 x 103 psi
Thermal Properties
Curie Temperature
430 °C 810 °F
Latent Heat of Fusion
270 J/g
Melting Completion (Liquidus)
1410 °C 2570 °F
Melting Onset (Solidus)
1450 °C 2640 °F
Specific Heat Capacity
460 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
17 W/m-K 9.8 BTU/h-ft-°F
Thermal Expansion
6.0 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
3.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
4.0 % IACS
Otherwise Unclassified Properties
Base Metal Price
49 % relative
Density
8.3 g/cm3 520 lb/ft3
Embodied Carbon
5.2 kg CO2/kg material
Embodied Energy
71 MJ/kg 30 x 103 BTU/lb
Embodied Water
190 L/kg 23 gal/lb
Common Calculations
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
23 points
Strength to Weight: Axial
17 to 29 points
Strength to Weight: Bending
17 to 24 points
Thermal Diffusivity
4.5 mm2/s
Thermal Shock Resistance
32 to 55 points
Alloy Composition
| Fe | 50.3 to 56 | |
| Ni | 28 to 30 | |
| Co | 16 to 18 | |
| Mn | 0 to 0.5 | |
| Si | 0 to 0.2 | |
| Cr | 0 to 0.2 | |
| Mo | 0 to 0.2 | |
| Cu | 0 to 0.2 | |
| Al | 0 to 0.1 | |
| Ti | 0 to 0.1 | |
| Zr | 0 to 0.1 | |
| Mg | 0 to 0.1 | |
| C | 0 to 0.040 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM F15: Standard Specification for Iron-Nickel-Cobalt Sealing Alloy
Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005