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Kovar expansion alloy 4J29, K94610, 1.3981

Alloy K / K94610 / ASTM F15 Also known as Kovar®*** and Nilo K**, this alloy contains 29% nickel with a 17% cobalt addition. Its composition is tightly controlled within narrow limits to ensure precise and universal thermal expansion and mechanical characteristics. This helps the material provide high integrity glass-to-metal and ceramic-to-metal seals in applications requiring reliability and resistance to thermal shock. Alloy K is often used for the manufacture of hermetic seals with both the harder Pyrex or borosilicate glasses and alumina-type ceramic materials. It finds extensive application in the production of transistors and diodes for lids and closures in a variety of hybrid electronic circuit packages and also in the manufacture of microwave tubes.

Chemical Content request :

Element 4J29 K94610 1.3981
C ≤0.03 ≤0.04 ≤0.05
Si ≤0.30 ≤0.20 ≤0.30
Mn ≤0.50 ≤0.50 ≤0.50
P ≤0.020
S ≤0.020
Ni 28.5~29.5 29.0* 28.0~30.0
Co 16.8~17.8 17.0* 16.0~18.0
Cr ≤0.20 ≤0.20
Cu ≤0.20 ≤0.20
Mo ≤0.20 ≤0.20
Al ≤0.10
Mg ≤0.10
Zr ≤0.10
Ti ≤0.10
Fe   Bal.* Rest



Special Metals Nilo® K
Franch Aperam Alloys Imphy(Imphy Alloys) Dilver P1®
Germany VDM Metals Pernifer® 2918

UNS K94610
Werkstoff Nr 1.3981
DIN 17745 
ASTM F 15 
AMS 7726 Wire 
AMS 7727 Bars and Forgings
AMS 7728 Sheet, Strip and Plate
MIL-I-23011 class 1
AFNOR NF A54-301
S.E.W 385

KOVAR alloys achieve a tight mechanical connection between two materials over a range of temperatures, suitable for glass/ceramic-metal seals in scientific equipment, as well as conductors into glass envelopes for electronic components, such as vacuum tubes (valves), X-rays and Microwave tubes, transistors, diode integrated circuits, etc.


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