Kovar 29 alloy 4J29 kovar metal china supplier kovar plate ring manufacture
Chemical compostion of Kovar 29/4J29
Description of Kovar 29/4J29
Kovar alloy is a vacuum melted, iron-nickel-cobalt, low expansion alloy whose chemical composition is controlled within narrow limits to assure precise uniform thermal expansion properties. Extensive quality controls are employed in the manufacture of this alloy to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining.
Applications of Kovar 29/4J29
Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials.
This alloy has found wide application in power tubes, microwave tubes, transistors and diodes. In intergrated circuits, it has been used for the flat pack and the dual-in-line package.
Physical Properties of kovar 29
Specific gravity.......................................8.36 Curie temperature
Density °F.................................................... 815
Kovar alloy is magnetic at all temperatures below the Curie point. Magnetic properties will depend upon heat treatment; the lower the hardness, the higher the permeability values and lower hysteresis loss. Examples of permeability properties are shown in the following chart:
1830°F (999°C) 30 min. - FC Permeability
2010°F (1099°C) 20 min. - FC Permeability
500 1000 2000 5000 10000 12000
1000 1400 2000 2300 3400 3000
1900 3500 5800 10000 8200 5000
Thermal Expansion Properties of Kovar29/ 4J29
The following are the average coefficient of expansion properties after annealing in hydrogen for 1 hr at 1650°F (900°C) and 15 minutes at 2010°F (1099°C) and cooled to room temperature within 1 hr. Material heat treated using this procedure should not exhibit any transformation when cooled to -112°F (-80°C) for 4 hrs. This was determined by means of metallographic examination.
Mean coefficient of thermal expansion as annealed.10(-6)/°C
Tested parallel to the direction of rolling. Material annealed 1830°F for 30 minutes,furnace cooling:
% Elongation in 2"
Hardness Rockwell B
After Processing And Before Packing
1. Chemical Compositon Inspection
3.Metallurgical Microscope Inspection.
4.Physical Property Inspection
6.Heterogeinity Of Carbides
7.Other test needs by negotitate
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