4J29 Kovar alloy is equivalent to GB 4J29, ASTM F15, UNS K94610); KOVAR is a hard glass iron based sealing alloy containing 29% nickel and 17% cobalt. This alloy has a linear expansion coefficient similar to that of hard glass in the range of 20~450 ℃, which can effectively seal and match with the corresponding hard glass. It also has a high Curie point and good low-temperature structural stability. The oxide film of the alloy is dense, easy to weld and melt, has good plasticity, can be cut and processed, and is widely used in the production of electric vacuum components, emission tubes, picture tubes, switch tubes, Transistors, as well as sealed plugs and relay housings. Kovar alloy is more wear-resistant due to its cobalt content. Kovayi is sealed with molybdenum glass, and the surface of the workpiece generally requires gold plating.
Corresponding brand:
| GB/T | AISI/ASTM | JIS | W.NR |
| 4J29 | F15 | EMAS-1001 | 1.3912 |
Chemical composition:
| C | MN | SI | F | S | CU | CR | MO | NI | CQ | FE |
| ≤0.03% | 0.50% | 0.30% | 0.20% | 0.20% | 0.20% | 0.20% | 0.20% | 28.5～29.5% | 16.8～17.8% | Remainder |
Application field:
This alloy is a typical Fe Ni Co hard glass sealing alloy commonly used internationally. Stable performance after long-term use in aviation factories. Mainly used for glass sealing of electronic vacuum components such as emission tubes, oscillation tubes, ignition tubes, magnetrons, transistors, sealed plugs, relays, integrated circuit leads, chassis, casings, brackets, etc. In application, the expansion coefficient of the selected glass and alloy should be matched. Strictly inspect the low-temperature tissue stability according to the usage temperature. During the processing, appropriate heat treatment should be carried out to ensure that the material has good deep drawing and elongation performance. When using forged materials, their airtightness should be strictly inspected.
