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4J29 (Kovar) is a seamless tube made of iron nickel cobalt fixed expansion glass sealing alloy, with the domestic grade 4J29 and internationally recognized Kovar. It is mainly used for precise thermal expansion matching with borosilicate hard glass and high airtight vacuum sealing. It is a core pipe material for semiconductor, electric vacuum, and aviation precision sealing.
The common grades of 4J29 are:
National standard: 4J29, American standard: Kovar/UNS K94610, Russian standard: 29 НК, German standard: Vacon12, Execution standard: YB/T 5231-2014;
The main heat treatment process of 4J29 (Kovar) is hydrogen protected annealing: holding at 900 ℃ for 1 hour → holding at 1100 ℃ for 15 minutes, slowly cooling to below 200 ℃ before being removed from the furnace to stabilize the expansion coefficient, eliminate stress, and ensure the sealing life.
Typical application scenarios of 4J29:
Semiconductor devices, electric vacuum devices, aerospace, instrumentation, new energy, vacuum equipment, high and low temperature precision pressure sealed pipelines, etc;
