Technological watch: Materials used in the tooling field : Composite tools of the cermet type (carbides)

Omnipresent in machining (cutting, milling, drilling, turning, ...), carbide has all the necessary qualities in terms of hardness and heat resistance for working a very wide range of materials such as high-speed steel, copper alloys or titanium alloys, at both conventional and high speeds. Reinforced with polycrystalline diamond or boron nitride coatings, for example, carbide tools are suitable for extreme applications on materials up to 70 HRC hardness.

The characteristic composition of carbide places it in the category of cermets, a family of metal matrix composites with ceramic reinforcement, designed to combine the optimum properties of a ceramic, such as hardness, abrasion resistance and resistance to high temperatures, with those of a metal, such as the ability to undergo plastic deformation (ductility).

Carbide particles, consisting of carbon molecules and an element other than oxygen, are bound together by a metallic binder. The most common metals are nickel, molybdenum, tungsten and cobalt. One of the most commonly used forms is that of tungsten carbide ('hard phase'), combined with cobalt (metallic binder). The hundred or so grades available on the market are obtained by varying the proportions of the hard phase of the carbide and the metallic binder.

Cemented Carbide Tooling

A cemented carbide is a cermet-type metal matrix composite in which the matrix is cobalt and the reinforcement is usually tungsten carbide (WC), titanium carbide (TiC) or tantalum carbide (TaC). The terms carbide and tungsten carbide in an industrial context generally refer to this type of cermets.

Cemented carbide cutting tools generally produce surfaces with a better finish than with HSS or other tool steels. They can withstand higher temperatures at the interface between the workpiece and the cutting tool, allowing higher machining speeds to be achieved. Cemented carbide is generally better at cutting tough materials such as carbon steel and stainless steel, as well as in situations where other cutting tools would wear out faster, such as in high production.

Technical economic progress announced for carbide tools

The overall performance offered by carbide tools seems to promise them a strong predominance on the machining market.

The greater control of tooling performance also opens up the market to the manufacture of customised machining tools, with the development of customised carbide tools at competitive prices.

The development and manufacture of this range of tools should also benefit from the increasing use of additive manufacturing.

There is also a growing demand for smaller tungsten carbide cutting tools, particularly small-diameter carbide milling cutters, associated with the evolution of industrial production towards lighter and more compact products and components, requiring micro-precision machining processes adapted to the new products of the digital and connected economy (electronics, aeronautics, medical, etc.).

Re-tooling, re-sharpening and reconditioning of existing carbide cutting tools seems to be an attractive area for investment, which should add to the sustainable and cost-competitive efforts of the carbide tool market as a whole.