History of tungsten

In the beginning

Tungsten, like all the elements having a higher atomic number than iron (Z>26), cannot be formed by nuclear fusion processes in stars, as is the case for those elements with a lower atomic number, but originates only by neutron or proton absorption of already existing bigger nuclei. These capture processes with extremely high fluxes of neutrons and protons which occur exclusively in massive stars (>8 times the solar mass) during the end of their life cycle. Massive stars end in a supernova explosion whereby certain amounts of their mass are distributed to the surrounding space, including also the tungsten atoms formed.

Stars of more than eight times the solar mass have to end in a supernova explosion to create the conditions necessary for the formation of the element tungsten.

Wolfram

Wolframite is one of the commercially important minerals for tungsten production.

“It tears away the tin and devours it like a wolf devours a sheep.”

In the Middle Ages (16th century) tin miners in the Saxony-Bohemian Erzgebirge in Germany reported about a mineral which often accompanied tin ore (tinstone). From experience, it was known that the presence of this mineral reduced the tin yield during smelting. Today, we know that this mineral was wolframite, one of the commercially important minerals for tungsten production.

“Wolffshar” was the ancient name for wolframite, because of its black colour and hairy appearance.

Georgius Agricola was the first to report about this new fossil (Spuma Lupi) in his book “De Natura Fossilium”, published in 1546. Foam appeared on the surface of the tin melt and a heavy deposit formed in the smelting stove, which retained the valuable tin. “It tears away the tin and devours it like a wolf devours a sheep”, a contemporary wrote in the symbolic language of those times. The miners gave this annoying ore German nicknames like “wolffram”, “wolform”, “wolfrumb” and “wolffshar” (because of its black colour and hairy appearance).

Tungsten

Carl Wilhelm Scheele (1742-1786)

In the 18th century geology and mineralogy developed into popular science and stones were collected for inspection. Professor Axel Fredrik Cronstedt in Uppsala received heavy stones from all around Sweden. Heavy stone in Swedish is called “Tung-Sten”.

In 1781, Carl Wilhelm Scheele managed to extract a still “unknown earth” from a heavy stone from the Bispberg iron mine, named Bispberg Tungsten. He called this new compound tungstic acid, and he is considered the discoverer of tungsten oxide. In recognition of his discovery, the other important mineral for tungsten production (besides wolframite) is called scheelite.

Professor Torbern Bergman in Uppsala suggested preparing the corresponding metal by charcoal reduction of the obtained tungstic acid. Being a famous professor, he himself was too busy with other things and did not perform the respective experiments.

Cover of Scheele’s publication from 1781; Images courtesy of the Library & Information Centre, Royal Society of Chemistry.

The tungsten ore now called scheelite is named after Carl Wilhelm Scheele.

Discovery of the element

Brothers Juan José Elhuyar (1745-1796) and Fausto Elhuyar (1755-1833) featured on a commemorative Spanish stamp. Copyright Sociedad Estatal de Correos y Telégrafos, SA.

At the same time in 1781/1782, the Spanish nobleman, Juan José de D´Elhuyar, studied metallurgical chemistry with Professor Bergman and gathered information about the work on the mineral tungsten.

Back in Spain in 1783, Juan José analysed a wolfram species from a tin mine in Zinnwald/Saxony and showed it to be an iron and manganese salt of a new acid. He also concluded that wolfram contained the same acid as Scheele had gained from tungsten. He then reduced the oxide to the new metal by heating it with charcoal, as had been recommended by his teacher, Professor Bergman.

His discovery, jointly with his brother Fausto Jermin, was published in 1783 by the Royal Society of Friends of the Country in the City of Victoria (“Analysis quimico del volfram, y examen de un Nuevo metal, que entra en su composition por D Juan Joséf y Don Fausto de Luyart de la Real Sociedad Bascongada”).  The new metal was named volfram after the mineral used for analysis.

Early tungsten development

Robert Oxland’s work opened the way to industrialisation.

Oxland patent dated 1847

Thereafter, an increasing number of scientists explored the new chemical element and its compounds. However, the price for the metal was still very high and the time was not yet ripe for promising applications.

In 1847, a patent was granted to the engineer Robert Oxland (1820–1899). This included the preparation of sodium tungstate, formation of tungstic acid, and the reduction to the metallic form by oil, tar or charcoal.

The work constituted an important step in modern tungsten chemistry and opened the way to industrialisation.

But tungsten was still a bit of a curiosity.

Excerpts from “Playbook of Metals” by John Henry Pepper, 1861.
Download a copy courtesy of Science History Institute.

Tungsten in steel

Robert Forester Mushet (1811-1891), father of the self-hardening steel in 1868. Image courtesy Sheffield Industrial Museums Trust.

Frederick Winslow Taylor (1856-1915), patented high speed steel in 1898. Image Wikipedia.

The first tungsten-containing steels were patented in 1858, leading to the first self-hardening steels in 1868.

High speed steels, with tungsten additions up to 20%, were first exhibited at the World Exhibition in Paris in 1900 and revolutionised engineering practice in the early 20th century. Such steels (Taylor- and White) are still used today in practically every machine shop in the world.

Early tungsten-containing steel production. Image courtesy Black Dwarf Lightmoor Publications / Keith Lloyd Webb.

Tungsten filaments in light bulbs

Early 20th century advertising posters for light bulbs with tungsten filaments. Tungsram image Wikimedia Commons. Philips image Wikimedia Commons.

The advent of electrical lighting offered another industrial opportunity for the element tungsten as filaments for light bulbs

The advent of electric lighting at the end of the 19th century, based on Thomas Alva Edison’s inventions in America and Werner Siemens’ work in Europe, offered another industrial opportunity for the element tungsten as filaments for light bulbs. Alexander Just and Franz Hanaman patented their manufacturing of “squirted” tungsten filaments in 1904 (BP: No. 23,899). Until 1911, most light bulbs in Europe and the USA were equipped with such filaments. The lamps produced significantly more light than the carbon filament lamps, with about a third of the energy required.

The real breakthrough came with William David Coolidge’s 1909 patent for General Electric in the US to produce ductile tungsten via a process called powder metallurgy today. Tungsten metal powder is pressed and sintered at high temperature to create solid tungsten bars, which could be swaged and hammered to smaller diameters and finally drawn to tungsten wire for use as filament in incandescent lamps. This allowed the production of big quantities of the highest quality.

Drawing tungsten wire using diamond drawing dies

William David Coolidge (1873-1975), originator of modern powder metallurgy. Image courtesy Harvard Square Library.

Tungsten carbide in tools

No one could have imagined the enormous breakthrough for cemented carbide products in the tooling industry all over the world.

To produce drawing dies with diamond-like hardness but improved toughness was the driving force for the development of cemented carbides in the 1920s.

This led to the invention of a material combining the hardness of tungsten carbide with the toughness of cobalt in 1923. The German Osram Study Group filed the patent, which was the birth of a material, still today called cemented carbide or hardmetal. At this time, no-one, even the most optimistic, could imagine the enormous breakthrough for this material in the tooling industry.

Friedrich Krupp AG was the first company to market the new material as tool material in 1927, under the brand WIDIA, which means “like diamond” (WIe DIAmant). After World War 2, a huge market opened in the growing economies and cemented carbides contributed as tool materials and construction parts for their industrial development.

Hardmetal production in Krupp’s WIDIA factory around 1930. Images courtesy of Widia-Handbuch 1936.

Tungsten the tooling element

 

Today tungsten can be called the element of tooling, as most high performance tools contain tungsten.

Tungsten made steel the better tooling material and increased the performance dramatically, as early as 1900. Together with carbon, as tungsten carbide, tungsten is the main constituent in hardmetal or cemented carbide, which has been the tooling material of choice since its invention in 1923.

Several technical improvements, such as coating of the hardmetal with thin layers of aluminum oxide (1974), titanium carbide (1969), titanium nitride (1970) and diamond (since the 1980s) further improved the performance, as did optimisation of the tool geometry and the combination of all these (ie multilayercoating, material compounds etc).

But the common denominator is still the use of tungsten.

Key improvements in machining performance. Training Handbook Metal Cutting Technology Sandvik Coromant C-2920:40 en-GB © AB Sandvik Coromant 2017; figure on page H45

Despite many years of tool development, tungsten is still a key element to achieve outstanding system performance.

Today tungsten can be called the element of tooling, as most high performance tools contain tungsten

Download the history of tungsten

For more information on the discovery and evolution of tungsten, download a PDF excerpt from the 134 page Tungsten brochure, published in 2009. To receive a free copy of the printed brochure, contact the ITIA Secretariat (info@ita.info) and provide your postal address.

Download the history of tungsten carbide / hardmetals

Tungsten carbide / cobalt hardmetals are key applications for tungsten. They originate from a patent of the Osram Study Group, filed in 1923.  On the “Hardmetal Century Celebrtation”, hosted by OMCD Group in Italy in 2023, ITIA presented “The story of tungsten and hardmetal from discovery, development to challenges and opportunities” for these unique materials.  

Main banner courtesy of NASA and the Space Telescope Science Institute (STScI). Historical company brochure images courtesy of Professor W D Schubert collection – original brochures copyright of respective companies.