Tungsten derives its name from the Swedish “Tung Sten,” which translates to “heavy stone.” Tungsten is a metal that is gray-white in color. This metal is stable and exhibits high resistance to acids and bases. Tungsten possesses the highest melting temperature among metals. These properties make tungsten valuable for many applications, including electrical, manufacturing, construction and chemical.
Light bulb filaments are one of the most well-known applications of tungsten. Tungsten finds its largest commercial application in the lamp industry. Tungsten is capable of tolerating very high temperatures and has extremely low vapor pressure, properties which contribute to increased luminosity and long life of the bulb. Domestic lamps, vehicle lamps and reflector lamps used in projectors and floodlights are some examples of applications where tungsten filaments are used. Specialty lamps such as those for video camera lights, airport runway markers, medical equipment and fiber-optic systems also use tungsten.
When mixed with other metals, tungsten results in alloys with special properties that are useful for a variety of applications. Alloys of cobalt and chromium with tungsten are called stellites, which exhibit excellent wear-resistant properties. Stellites are used in bearings, pistons and valve seats, as well as in applications that require materials with tough wear-resistant properties. When mixed with heavy concentrations of tungsten, molybdenum, tantalum and rhenium, the metals nickel, iron or cobalt form superalloys. Superalloys exhibit several special properties including high temperature tolerance, high corrosion resistance and excellent welding properties. Applications of superalloys include marine vehicles, the turbine blades of aircraft engines, and turbine vanes and blades in stationary power supplies.
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Tungsten and Steel
The addition of tungsten makes steel stronger. Tungsten increases steel’s hardness and cutting capacity. Tungsten is the primary alloy component in steels used for tools and construction. Steel alloys with tungsten are used for cutting and making metal components. As such, it is important that these steel alloys possess excellent hardness properties over a wide range of temperatures.
Tungsten finds many applications in laboratories. It serves as a reagent in the form of high purity sodium tungstate in biochemical analysis. As sodium metatungstate, the metal is used in mineralogy for preparing heavy liquids for separating minerals on the basis of their density. Granules of high purity tungsten are used as an accelerator in the process of determining carbon and sulfur in metals.