High quality 4J29 Kovar pipe tube with ASTM F15

4J29 Kovar is A Nickel-Iron-Cobalt, controlled expansion alloy containing 29% Nickel. It’s coefficient of expansion (which decreases with rising temperature to the inflection point), matches the expansion rate of borosilicate glasses and aluminia ceramics. Applications include glass to metal seals in applications requiring high reliability or resistance to thermal shock, ie. high-power transmitting valves, transistor leads and heaters and photography flash bulbs.