A great number of applications of tungsten are based on its high melting point and its low vapour pressure. Tungsten remains an excellent material for high-vacuum technology up to the highest temperatures. Low thermal expansion combined with its high melting point and its perfect form stability make tungsten an excellent material for glass seals. The electric resistance of tungsten is important for its use as heater material for high-temperature furnaces. Thanks to its high density gives tungsten a good absorption ability for ionising radiation. At ambient temperature, ordinary tungsten is rather brittle and therefore difficult to process. At higher temperatures (between 200 and 500 °C), however, it changes to a ductile condition. Tungsten's high temperature strength and strain depends on deformation and annealing pretreatment may vary significantly at certain temperatures.
Advantages of W for high temperature applications:
- high melting temperature
- low vapour pressure
- sufficiently high electrical resistance
- low thermal expansion combined with good thermal conductivity
- high E-modulus
Typical areas of application:
- components for the high temperature furnace construction
- parts for the manufacture of quartz glass
- electrodes for the joining technology and lighting industry
