Soft Magnetic Alloy Polished Rod 4 J29 Alloy

4 j29 overview
4 j29 alloy is also called the Kovar Kovar alloy. The alloy in the 20 ~ 450 C has close to silicon boron hard glass linear expansion coefficient, high Curie temperature, and have good organizational stability at low temperature. Alloy oxide film density, can cover glass infiltration. And not to the role of mercury, suitable for use in mercury discharge appearance. Material is main seal structure for vacuum electronic devices.
Edit this paragraph 4 j29 material mark
4 j29.
Edit this paragraph 4 j29 similar grades
Russia America Britain France, Germany, Japan
29 h Kovar KV Nilo K - 1 Dilver P0 Vacon 12
29 h Rodar KV - 2
29-17 Techallony Glasseal Telcaseal KV - 3 Dilver P1 Silvar 48
Edit this paragraph 4 j29 material technical standards
YB/T 5231-5231 "iron nickel and cobalt glass sealed 4 j29 alloy and 4 j44 technical conditions".
Edit this paragraph 4 j29 chemical composition
C or less 0.03% Mn Si acuities were 0.50% and 0.30% or less P 0.020% S 0.020% Cu 0.20% or less or less or less Cr Mo acuities were 0.20% and 0.20% or less
Ni Co = 16.8 = 28.5 ~ 29.5% ~ 17.8%
Fe = allowance
Under the condition of average linear expansion coefficient reach standard, allow the content of nickel and cobalt deviation range given in table 1 and 2. Aluminum, magnesium, zirconium and titanium content is more than 0.10%, the total amount should be no greater than 0.20%.
Edit this paragraph 4 j29 heat treatment system
The expansion coefficient and low temperature stability of the standard of performance test sample, heated to 900 C in hydrogen atmosphere - 20 C, insulation 1 h, and then heated to 1100 C+ 20 C, the heat preservation for 15 min, is not greater than 5 C / min speed cold to below 200 C.
Edit this paragraph 4 j29 application and special requirements
The alloy is international typical Fe - Ni - Co alloy hard glass sealing. Via air factory use for a long time, stable performance. Mainly used in electric vacuum components such as tubes, oscillation tubes, ignitron, magnetron, transistors, the wires of a sealing plug, relays, integrated circuits, chassis, casing glass seal, support, etc. That should be chosen in the application of matching expansion coefficient of glass and metal. According to the using temperature strictly check its organizational stability at low temperature. In the process of processing should be proper heat treatment, to ensure that the material has good deep drawing extension performance. When use forged materials should strictly the air tightness test.
Edit this paragraph 4 j29 alloy structure
Alloy after heat treatment system to deal with, as stipulated in the 1.5 78.5 C and then frozen, there should not be a martensite structure is greater than or equal to 4 h. But when the alloy composition is not at the time, will happen under normal temperature or low temperature varying degrees of austenite (gamma) to acicular martensite (alpha), phase change with the volume expansion effect. Higher corresponding expansion coefficient of metal, causing the internal stress of sealing a surge, even causing the damage. Main factors affecting the stability of alloy cold organization is alloy chemical composition. From Fe - Ni - Co can be seen in the ternary phase diagram, is stable gamma phase of the main elements of nickel, nickel content on the high side for gamma phase stability. With the increase of alloy total deformation rate the stabilized its organization. Alloy composition segregation can also cause gamma - alpha phase transition in the local area. In addition coarse grains can promote gamma - alpha phase transition.