Of all the metals, tungsten is the most difficult to melt and the least volatile, so it is called a "high-melting metal," with a melting point of up to 3,380 degrees and a boiling point of 5,927 degrees.
The Latin word for tungsten means "foam in the mouth of a Wolf." How could tungsten be associated with a carnivore? It turns out that long ago, when tin was refined from ore, it was found that whenever the ore contained a heavy brown stone, the yield of tin dropped sharply. Turns out this heavy stone eats tin like a Wolf eats sheep. So tungsten is called "Wolf foam." Tungsten is about 1 in 100,000 parts of the earth's crust. There are ferrous tungsten manganese ore in nature (also called wolframite) and yellow gray calcium tungstate ore (also called scheelite), China's tungsten reserves occupy the first place in the world. China's Nanling, is the world's richest tungsten ore zone, especially in the southwest of The Yangtze River, known as the "metal town". Dayu in Jiangxi and Shizhuyuan in Hunan have the world's largest tungsten mines. Tungsten was discovered as early as the 18th century, but it was not until 1850 that wohler made pure metal tungsten. But since then it has been widely used. In addition to filament, it is also used as a high-performance cutting tool.
In 1864, Marchett, an Englishman, was the first to add 5% tungsten to steel to produce an alloy that kept its high hardness unchanged. The cutting speed of metal can be increased from 5 meters per minute to 7.5 meters per minute by using this steel as a tool. Due to the development of high speed steel with different tungsten content, the cutting speed is gradually increased. Over more than 40 years, tungsten steel tools have increased metal cutting speeds to 35 meters per minute, increasing cutting capacity by a factor of six.
In 1907, the development of "Staley" cemented carbide, an alloy based on tungsten, chromium and cobalt, made it possible to achieve even higher cutting speeds.
Modern supercarbides are produced from tungsten carbide and some other elemental carbides by sintering. It is difficult to melt metal (tungsten, tantalum, titanium, molybdenum, etc.) carbide hard particles, with one or several iron group elements (cobalt, nickel or iron) powder mixed molding, and then made by sintering.
Cemented carbide is the strongest alloy in the world. There are two kinds of cemented carbides widely used at present: the first kind is tungsten carbide based alloy with cobalt as binder; The second type is a tool steel as a binder titanium carbide base alloy.
When carbide is used as a tool, its hardness will not be reduced even at 1000 degrees. As a result, high-speed cutting can be carried out, cutting speed per minute up to 2000 meters, more than 100 times higher than ordinary carbon steel tools, than tungsten steel tools are also 15 times higher. It produces a die that can be stamped more than 3 million times and is 60 times more durable than ordinary alloy steel dies.