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UNS K93600 (FeNi36, 1.3912) Low Expansion Alloy

K93600 alloy is an iron alloy formulated for controlled thermal expansion. 1.3912 is the EN numeric designation for this material. FeNi36 is the EN chemical designation. And K93600 is the UNS number.

It has the lowest electrical conductivity and can have the highest ductility among low-expansion iron alloys.

The properties of K93600 alloy include three 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 K93600 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 20 x 106 psi

Elongation at Break

5.0 to 35 %

Shear Strength

320 to 380 MPa 47 to 55 x 103 psi

Tensile Strength: Ultimate (UTS)

480 to 810 MPa 69 to 120 x 103 psi

Tensile Strength: Yield (Proof)

280 to 750 MPa 40 to 110 x 103 psi

Thermal Properties

Curie Temperature

250 °C 480 °F

Maximum Temperature: Mechanical

440 °C 820 °F

Melting Onset (Solidus)

1430 °C 2610 °F

Specific Heat Capacity

520 J/kg-K 0.12 BTU/lb-°F

Thermal Conductivity

13 W/m-K 7.5 BTU/h-ft-°F

Thermal Expansion

7.3 µm/m-K

Other Material Properties


8.1 g/cm3 510 lb/ft3

Electrical Conductivity: Equal Volume

2.2 % IACS

Electrical Conductivity: Equal Weight (Specific)

2.4 % IACS

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

21 to 280 MJ/m3

Resilience: Unit (Modulus of Resilience)

280 to 2050 kJ/m3

Stiffness to Weight: Axial

9.4 points

Stiffness to Weight: Bending

21 points

Strength to Weight: Axial

16 to 28 points

Strength to Weight: Bending

17 to 24 points

Thermal Diffusivity

3.1 mm2/s

Thermal Shock Resistance

34 to 57 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