Cemented carbide

The process of combining the carbide particles with the binder is referred to as sintering or hot isostatic pressing (HIP).

During this process, the material is heated until the binder enters a liquid phase while the carbide grains (which have a much higher melting point) remain solid.

The ductility of the metal binder serves to offset the brittleness of the carbide ceramic, resulting in the composite's high overall toughness and durability.

[1] The coefficient of thermal expansion of cemented tungsten carbide is found to vary with the amount of cobalt used as a metal binder.

[2] Carbide is more expensive per unit than other typical tool materials, and it is more brittle, making it susceptible to chipping and breaking.

In recent decades, though, solid-carbide endmills have also become more commonly used, wherever the application's characteristics make the pros (such as shorter cycle times) outweigh the cons (mentioned above).

Mining and tunneling cutting tools are most often fitted with cemented carbide tips, the so-called "button bits".

This category contains a countless number of applications, but can be split into three main areas: Some key areas where cemented carbide components are used: Tungsten carbide has become a popular material in the bridal jewellery industry, due to its extreme hardness and high resistance to scratching.

[3] ThyssenKrupp says [in historical present tense], "Sintered tungsten carbide was developed by the 'Osram study society for electrical lighting' to replace diamonds as a material for machining metal.

Not having the equipment to exploit this material on an industrial scale, Osram sells the license to Krupp at the end of 1925.

[3] Although the marketing pitch was slightly hyperbolic (carbides being not entirely equal to diamond), carbide tooling offered an improvement in cutting speeds and feeds so remarkable that, like high-speed steel had done two decades earlier, it forced machine tool designers to rethink every aspect of existing designs, with an eye toward yet more rigidity and yet better spindle bearings.

Regarding fine-grained hardmetal, an attempt has been made to follow the scientific and technological steps associated with its production; this task is not easy, though, because of the restrictions placed by commercial, and in some cases research, organisations, in not publicising relevant information until long after the date of the initial work.

However, it has been possible to establish that as far back as 1929, approximately 6 years after the first patent was granted, Krupp/Osram workers had identified the positive aspects of tungsten carbide grain refinement.

Pressed plates are sintered at a temperature close to the melting point of the binder metal, which yields a very tight and solid substance.