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Iron Nickel Cobalt Alloy Kovar bright wire

Basic Info

Model No.:  Kovar

Product Description

Model NO.: Kovar

Material: Fe-Ni-Co

surface: bright or black

Trademark: ToLand Alloy

Origin: China

Product Type: Wire

Carbon Content: Low Carbon

length: random, fixed

Specification: 6-300mm


4J29(China); 29H, 29H-B, Techallony(Russia); Kovar, Rodar, Glasseal 29-17(United States); Nilo K, Telcaseal(Great Britain); KV-1, KV-2, KV-3(Japan); Dilver P0, Dilver P1(France); Vacon 12, Silvar 48(Germany).

4J29 expansion alloy, also known as Kovar alloy, is a Nickel Iron alloy with 29% Nickel, 17% Cobalt and the remaining balance is Iron. The expansion characteristics of Kovar match both borosilicate (or Pyrex) glasses and alumina ceramics, making it one of the most popular controlled expansion alloys for hermetic sealing applications. Kovar is produced to ensure good properties for machining and deep drawing, and is a porosity free product. You'll find Kovar in applications such as power tubes, microwave tubes, transistors, diodes, hybrid packages, and other kinds of scientific instruments.


The alloy is widely used as glass sealing for electronic vacuum devices, such as launching tube, oscillating tube, ignitron, magnetron, transistor, sealing plug, relay, leading wire of integrated circuit, chassis, shell, scaffold and so on.

Physical Constants:


Specific gravity (g/cm3): 8.36

Melting point(ºC): 1450

Melting heat(calorie/g): 64

Vapour pressure (μ M): 1× 10-6 (1000ºC)

Specific heat(calorie/g/ºC): 0.105 (0ºC)

0.155 (430ºC)

Heat conductivity(calorie/cm· Sec. · ºC): 0.0395 (30ºC)


Curie temperature (ºC): 435

γ α Phase-transition temperature(ºC): Below -80

Electrical performance:

Resistivity (μ Ω -mm): 49 (25ºC)

Iron Nickel Cobalt Alloy Kovar bright wire

Varieties Steel type

Resistance Alloys for electrical heating Super alloy Welding Wire Corrosion resistant
Rods hot rolling rods Φ8~38mm available available available
Cold-drawn rods ≤50mm available available available
Forged rods Φ38~350mm available available available
Wires Round wires Φ0.3~8mm available available available available available
Non-circle wires Negotiation available available available
Strips Cold rolling 0.15~4×200mm available available available available
Hot rolling 4~22×200mm available available available available
Plates Cold rolling 0.5~4×1000×2000mm available available available
Hot rolling 4~22×1000×2000mm available available available
tubes Φ4~63×0.5~5mm available available
Executive standard: GB, GJB, HB, YB, ASTM, AMSE, negotiation and so on.

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Product Categories : Precision Alloy