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4j29 Kovar material

  • Author:naky
  • Source:www.diecastingpartsupplier.com
  • Release on :2016-06-22
Expansion coefficient and low temperature performance test sample of tissue stability standards for heating in a hydrogen atmosphere to 900 ℃ ± 20 ℃, insulation 1h, and then heated to 1100 ℃ ± 20 ℃, heat 15min, not more than 5 ℃ / min speed is cooled to below 200 ℃ baked


The alloy is the international typical Fe-Ni-Co hard glass sealing alloys. After long-term use of aviation factories, stable performance. Mainly used in electric vacuum components such as emission control, oscillating tube, igniting tubes, glass magnetron, transistors, seal plug, relay, IC lead, chassis, housings, brackets and other sealing. In the application should be the expansion coefficient of the glass and alloy selection matches. According to the strict inspection of its low temperature stability of the organization. In the process should be an appropriate heat treatment to ensure that the material has good extension of deep-drawing performance. When training materials should be used strictly verify its tightness.


After the heat treatment prescribed by 1.5 alloy processing system, and then by -78.5 ℃ frozen, should not be greater than or equal 4h martensite. But when the alloy composition is not the time, at room temperature or low temperatures will occur in varying degrees of austenite (γ) to acicular martensite (α) change, phase transition accompanied by a volume expansion effect. Expansion coefficient of the alloy increase accordingly, resulting in internal stress of the sealing member surge, and even cause some damage. The main factors affecting the low-temperature alloy microstructural stability of the chemical composition of the alloy. Can be seen from the Fe-Ni-Co ternary phase diagram of nickel is the main element of a stable γ-phase, high nickel content is conducive to stable γ phase. Alloy with total deformation rate increase more organizations tend to be stable. Alloy segregation may also result in local regions γ → α phase transformation. Furthermore coarse grains will also promote the γ → α phase transformation.