Suzhou Xunshi New Material Co., Ltd
SUZHOU XUNSHI NEW MATERIAL CO., LTD CHOOSE XUNSHI, CHOOSE HIGH PERFORMANCE
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Kovar Controlled Expansion Alloy Hot Forged Round Bar for Glass Sealing Application
A-ONE ALLOY keeps in stock Kovar hot fogerd round bar from diameter 20mm to diameter 300mm. And we could make fast delivery for customized sizes as well as forged pieces.
Kovar controlled expansion alloy, most likely know as 4J29 in China, is a Nickel Iron alloy with 29% Nickel, 17% Cobalt and the remaining balance is Iron.
Kovar controlled expansion alloy, was invented to meet the need for a reliable glass-to-metal seal, which is required in electronic devices such as light bulbs, vacuum tubes, cathode ray tubes, and in vacuum systems in chemistry and other scientific research area.
Kovar has thermal expansion similar to glass. Meanwhile its nonlinear thermal expansion curve can often be made to match a glass. This makes it the most popular controlled expansion alloy so far.
Chemical compostion of Kovar
| Alloy | % | Ni | Cr | Co | Cu | C | Mn | Si | P | S | Mo | Fe |
| Kovar | Min | 28.5 | 16.8 | Rem | ||||||||
| Max | 29.5 | 0.2 | 17.8 | 0.20 | 0.03 | 0.50 | 0.30 | 0.02 | 0.02 | 0.20 |
The average linear expansion coefficient(10-6C)
| 20~100°C | 20~300°C | 20~400°C | 20~450°C | 20~500°C | 20~530°C | 20~600°C |
| — | — | 4.6~5.2 | 5.1~5.5 | — | — | — |
Applications of Kovar
Forms available at A-ONE ALLOY