Uses and applications of tungsten

Tungsten carbide  Industry

Tungsten is an important alloying element that is widely used in the production of various steels. Common steels containing tungsten include high-speed steels, tungsten steels and tungsten-cobalt magnetic steels with high magnetisation strength and coercivity, which are mainly used in the manufacture of various tools such as carbide drills, carbide milling cutters, carbide wire drawing dies, negative and positive dies.

Tungsten carbide-based cemented carbide

Tungsten carbides are often used in a number of cemented carbides because of their high wear resistance and refractoriness, while their hardness is close to that of diamond. Currently the largest consumer of tungsten, tungsten carbide-based carbide is a powder metallurgical product made by sintering tungsten carbide micron-sized powder and metal binders (e.g. cobalt, nickel, molybdenum) in a vacuum furnace or hydrogen reduction furnace. Tungsten carbide-based cemented carbides are broadly classified into four categories: tungsten carbide-cobalt, tungsten carbide-titanium carbide-cobalt, tungsten carbide-titanium carbide-tantalum (niobium)-cobalt carbide and steel-junction cemented carbide. These tungsten carbide-based cemented carbides are mainly used in the manufacture of cutting tools, mining tools and wire drawing dies, etc.

Thermally strong and wear-resistant alloys

Tungsten has the highest melting point of all metals and is very hard, so it is often used to produce thermally strong and wear-resistant alloys. For example, alloys of tungsten and chromium, cobalt and carbon are often used to produce high strength and wear-resistant parts such as aero-engine valves and turbine impellers, while alloys of tungsten and other refractory metals (such as tantalum, niobium, molybdenum and rhenium) are often used to produce high thermal strength parts such as aero-rocket nozzles and engines.

Due to its high density and high hardness, tungsten has become an ideal material for making high specific gravity alloys. These high specific gravity alloys are divided into major series such as W-Ni-Fe, W-Ni-Cu, W-Co, W-WC-Cu, W-Ag, etc. according to their composition characteristics and usage. They are widely used in the aerospace, aviation, military, oil drilling, electrical instrumentation, medical and other industries, such as the manufacture of armour, heat sinks, balance hammers for control rudders and contact materials such as gate switches, circuit breakers, spot welding electrodes, etc.

Electronics or pure tungsten or copper tungsten

Tungsten and its alloys are widely used in the electronics and power supply industries because of its high malleability, low evaporation rate, high melting point and high electron emission capacity. For example, tungsten filaments are widely used in the manufacture of light bulb filaments, such as incandescent and tungsten iodide lamps, because of their high luminosity and long service life. Tungsten filaments are also used in the manufacture of direct hot cathodes and grids for electronic oscillation tubes and in the manufacture of side hot cathode heaters for various electronic devices. Tungsten's properties also make it suitable for TIG welding and other electrode materials for such work.

Chemical industry

Compounds of tungsten are often used as catalysts and inorganic colours, for example tungsten disulphide is used as a lubricant and catalyst in the manufacture of synthetic gasoline, bronze coloured tungsten oxide is used in painting, and calcium or magnesium tungsten is commonly used in phosphors.

Other applications

As tungsten has similar thermal expansion properties to boron silicate glass, it is used to make glass or metal seals. Tungsten's low sensitivity means that it is used to make high-purity tungsten gold jewellery. In addition, tungsten is also used in radiological medicine and some musical instruments use tungsten wire for their bronze rings.