What is Tungsten Carbide?
Although called as a “Hard Metal”, Tungsten Carbide by itself is actually a powder, you need a binder, like Nickel or Cobalt to form a composite material with hard particles of Tungsten Carbide embedded in it.
Tungsten Carbide Chemical Formula
The chemical formula for Tungsten Carbide is WC, where symbol ‘W’ come from its earlier name, Wolfram, and ‘C’ is for Carbon.
The History of Tungsten Carbide
Tungsten carbide is around 100 years old. Lohmann and Voigtländer applied for a patent for cast carbide in 1914. In 1923, Karl Schröder and Heinrich Baumhauer made it possible to patent sintered carbide, which was bought by the Osram company in German.
In 1926, hard metal came onto the market under the name Wiedia (Wie Diamant) from Krupp Hartmetall.
Tungsten Carbide Manufacturing Process
Tungsten Carbide is created using the Powder Metallurgy process, where tungsten carbide in the form of powder and cobalt is mixed using ball mill, and then the binder is added to hold the two powders to bind each other, then the next step is the compaction or pressing.
During the compaction processes, the isostatic hydraulic presses are used to compact the powder into a form of suitable with the desired design of the finished product.
In this way, this compacted powder combination can be easily worked using conventional metal working tools. The work process here is often referred to as “Green Machining”. Care must be taken in this process, because there are fine powder particles which can cause health hazards. The effective extraction methods are needed in this process.
After the “Green Machining” process, the compacted powder is ready to be sintered. Usually this is done in a vacuum furnace at temperatures between 1300 to 1600 degrees Celsius.
The sintering process will produce a fused Tungsten Carbide and cobalt matrix to produce a dense and very “Hard Metal”.
After this sintering process, this Hard Metal becomes very difficult to be worked further, so it can only be machined by diamond grinding. This is a relatively expensive process of micro machining because it takes quite a long time, and it is not possible to remove most of the unwanted Hard Metal material with this process.
Applications of Tungsten Carbide
Tungsten Carbides has many applications, ranging from the industrial sector such as metal machining, wear-resistant parts in the mining and oil industry (drill tools, etc.), metal forming tools, cutting tip in saw blades, bullets and sabot-projectiles in military weapons, and now it has been widely applied to consumer goods such as wedding rings and watch boxes, as well as the ball on a ballpoint pen.