Carbide is the most widely used class of high-speed machining (HSM) tool material, such material is produced by powder metallurgy process, made of hard carbide (usually tungsten carbide WC) particles and the soft texture of the metal-binding agents components. Currently, there are hundreds of different components of WC-based cemented carbide, most of them are used cobalt (Co) as a binder, nickel (Ni) and chromium (Cr) element is also commonly used binding agent, may be added other additional Some alloying elements. Today, I will introduce the main milling process of carbide cutting tools.

Tungsten carbide powder is obtained by tungsten (W) powder obtained by carburizing. Tungsten carbide powder characteristics (especially the particle size) depends on the temperature and time of the feedstock tungsten powder particle size and carburization. Chemical control is also critical, the carbon content must be kept constant (close to the weight ratio of 6.13% of the stoichiometric value). By a subsequent step in order to control of particle size, may be added a small amount of vanadium and / or chromium prior to carburizing treatment. Different processing conditions and different downstream end-processing requires the use of specific combinations of tungsten carbide grain size, carbon content, vanadium content and chromium content, by a combination of these changes, can produce a variety of tungsten carbide powder. Carbide cutting tools, for example, tungsten carbide powder manufacturer ATI Alldyne company produced a total of 23 kinds of standard grades of tungsten carbide powder, and customized according to user requirements tungsten carbide powder varieties up to 5 times more than standard grades of tungsten carbide powder.
    

In the tungsten carbide powder and a metal binder were mixed together to produce a grade of carbide milled powder, it is possible using a variety of different combinations. The most common cobalt content of 3% to 25% (by weight), whereas in the case of the need to enhance the corrosion resistance of the tool, is necessary to add nickel and chromium. In addition, you can also add other alloying elements, and further improve the metal binder. For example, adding ruthenium in WC-Co cemented carbide, may be made without reducing its hardness premise significantly improve its toughness. Increase the binding agent content can also increase the toughness of cemented carbide, but it will reduce its hardness.

Reduce the size of tungsten carbide particles can improve the hardness of the material, but in the sintering process, the tungsten carbide particle size must remain unchanged. During sintering, the tungsten carbide particles by dissolving and re-precipitation process combined with growing up. In the actual sintering process, in order to form a fully dense material, the metal binder to become liquid (called liquid phase sintering). By the addition of other transition metal carbides, including vanadium carbide (VC), chromium carbide (Cr3C2), titanium carbide (TiC), tantalum carbide (TaC) and niobium carbide (NbC), tungsten carbide particles can grow up control speed. These are usually metal carbide when the tungsten carbide powder and a metal binding agent were mixed together was added milled, although vanadium carbide and chromium carbide may be formed at the time of carburized tungsten carbide powder.

Recycled scrap carbide materials can also produce grades of tungsten carbide powder. Carbide waste recycling and reuse in the carbide industry has a long history, is an important part of the economy as a whole chain of the industry, it helps to reduce material costs, conserve natural resources and avoid waste material-free harmful disposal. Carbide generally used by APT (ammonium paratungstate) process, or by a zinc recovery process after grinding for reuse. These "regenerated" tungsten carbide powder typically has better predictable density, because the surface area is smaller than directly formed by the carburization process of the tungsten carbide powder.

 Tungsten carbide powder and binder mixed metal milling processing conditions is critical process parameters. The two most commonly used technique is the milling and ultrafine grinding mill. Both processes make the milled powder were uniformly mixed, and to reduce the particle size. In order to suppress subsequent workpiece has sufficient strength to maintain the shape of the workpiece, and the operator can pick up a workpiece or robot operation, when the milling is usually also need to add an organic binding agent. Chemical composition of carbide cutting tools such binding agents can affect the density and strength pressed into the workpiece. In order to facilitate the operation, it is best to add high-strength bond, but this will result in lower pressing density, and may cause lumps, causing defects in the final product.

After the completion of milling, spray-dried powder will typically produce agglomerate together by an organic binder free flowing agglomerates. By adjusting the composition of the organic binder, can be customized mobility and charge density of these clumps needed. By filtering out the coarse or finer particles, the agglomerates can be further customized particle size distribution, to ensure that it has good fluidity at mount mold cavity.