Kovar® Typical Properties & Standards – ASTM F15

Pernifer® 2918, Dilver® P1, Nilo® K

kovar properties physical mechanical expansion chemistry specificationsEFINEA knows how important the properties of Kovar®, ASTM F15 are to you when evaluating this alloy for an application.  As a reference, we have comprised typical key data points to guide customers in their assessment of Kovar®, ASTM F15 Alloy properties.  The tables include the mean coefficient of thermal expansion as annealed, physical, mechanical and chemical properties, as well as specifications.


For further information on Kovar® ASTM F15 Alloy, do not hesitate to call us at 800-348-6268.  Our professional sales team are experts in the materials we sell and will always assist you in finding a solution to your alloy needs.


To download a copy of the EFINEA Kovar® | ASTM F15 Alloy data sheet, or any of our other Controlled Expansion Alloy data sheets, please navigate to the Data Sheets section in our Technical Library.


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Mean Coefficient of Thermal Expansion As Annealed

Temp Range
77°F to
Temp Range
25°C to
30°C to
µm/m • °C
572°F2.85300°C 5.13
662°F2.72350°C 4.89
752°F2.81400°C 5.06400°C4.60 to 5.20*
842°F2.92450°C 5.25450°C5.10 to 5.50*
932°F3.41500°C 6.15
1112°F4.34600°C 7.80
1292°F5.06700°C 9.12
Average coefficient of expansion properties after annealing in hydrogen for one hour at 1650 °F (900°C) at 15 minutes at 2010° F (1099°C) and cooled to room temperature within one hour.
Source: CarTech® Kovar Alloy Data Sheet v. 10/90. *ASTM F15 Table 4

To compare the linear coefficient of thermal expansion across our line of controlled expansion glass and sealing alloys, please refer to the Thermal Expansion Table.

ASTM F15 Alloy (Kovar®) Typical Physical Properties

Densitylb/cu in0.302
Specific Gravity8.36
Curie Temp°F815
Melting Point°F2640
Electrical Resistivity (70°F)ohm-cir mil/ft294
Thermal ConductivityBTU-in/sq. ft-hr-°F 120
W/cm °C0.17
Specific HeatCal/gm °C0.11
BTU/lbm- °F0.11
Source: CarTech® Kovar Alloy Data Sheet v.10/90. | ASTM F15

ASTM F15 Alloy (Kovar®) Typical Mechanical Properties

*Tensile Strengthksi (MPa)75 (517)
**Sheet + Strip, Temper A, Annealedksi (MPa)82 (570) max
**Rod + Wire,
Temper A, Annealed
ksi (MPa)85 (585) max
*Yield Strengthksi (MPa)50 (345)
*Elongation% in 2"30
*Typical Hardness (Annealed) Rockwell B68
Modulus of Elasticityksi (GPa)20,000 (138)
Poisson's Ratio0.317
*Kovar strip tested parallel to the direction of rolling. Material annealed 1830 °F (999°C) for 30 minutes, then furnace cooled.
** Per ASTM F15, Temper A, Annealed
Source: CarTech® Kovar Alloy Data Sheet v.10/90. | ASTM F15

ASTM F15 (Kovar®) Chemistry

Composition %
Iron, nominal53.00
Nickel, nominal29.00
Cobalt, nominal17.00
Manganese, max0.50
Silicon, max0.20
Carbon, max0.04
Copper, max0.20
Chromium, max0.20
Molybdenum, max0.20
Aluminum, max0.10
Magnesium, max0.10
Zirconium, max0.10
Titanium, max0.10
The iron, nickel and cobalt % listed are nominal. They shall be adjusted by the manufacturer so that the alloy meets the requirements for coefficient of thermal expansion
The total aluminum, magnesium, zirconium and titanium shall not exceed 0.20%
Source: ASTM F15-04 (2017) Table 1

ASTM F15 (Kovar®) Specifications

UNS K94610
AMS 1-23011 CL1 MIL 1-23011 CL1

ASTM F15 (Kovar®) Specifications- Historic Cross- Reference

ASTM F1466UNS K94360AMS 7726B, 7727, 7728C

For additional information on specifications of the materials distributed by EFINEA, please visit the websites of the international organizations that develop and publish technical standards: ASTM International and ASM International.

EFINEA supplies the highest quality special purpose metals and alloys.  We stock controlled expansion, refractory, soft magnetic alloys and electronic nickels found in applications for aerospace, aviation, defense, electronics, energy, medical, optical, research and other high-technology industries.