UNS K94200 (FeNi42, 1.3917) Low Expansion Alloy
K94200 alloy is an iron alloy formulated for controlled thermal expansion. 1.3917 is the EN numeric designation for this material. FeNi42 is the EN chemical designation. And K94200 is the UNS number.
The properties of K94200 alloy include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare K94200 alloy 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
140 GPa 21 x 106 psi
Elongation at Break
5.0 to 32 %
Poisson's Ratio
0.34
Shear Modulus
54 GPa 7.8 x 106 psi
Shear Strength
330 to 410 MPa 48 to 60 x 103 psi
Tensile Strength: Ultimate (UTS)
500 to 710 MPa 73 to 100 x 103 psi
Tensile Strength: Yield (Proof)
270 to 650 MPa 39 to 94 x 103 psi
Thermal Properties
Curie Temperature
350 °C 660 °F
Melting Onset (Solidus)
1440 °C 2620 °F
Specific Heat Capacity
500 J/kg-K 0.12 BTU/lb-°F
Thermal Conductivity
15 W/m-K 8.7 BTU/h-ft-°F
Thermal Expansion
5.0 µm/m-K
Other Material Properties
Density
8.2 g/cm3 510 lb/ft3
Electrical Conductivity: Equal Volume
2.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
3.0 % IACS
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
35 to 130 MJ/m3
Resilience: Unit (Modulus of Resilience)
250 to 1460 kJ/m3
Stiffness to Weight: Axial
9.8 points
Stiffness to Weight: Bending
21 points
Strength to Weight: Axial
17 to 24 points
Strength to Weight: Bending
17 to 22 points
Thermal Diffusivity
3.7 mm2/s
Thermal Shock Resistance
49 to 70 points
Followup Questions
Further Reading
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