Carbide is a metal that's used to make many types of tools, including saw blades, drill bits and dental drilling tips. It comes in different grades--ranked from soft to hard--and each has its own unique properties that influence how it withstands shock, wear and heat.
The two primary properties in carbide that affect its behavior in cutting applications are hardness and toughness. The former translates to the ability of a tool to resist high temperatures during metalcutting, while the latter reflects its resistance to pressure and impact.
Tungsten promotes hardness, while carbon increases it even further and cobalt intensifies its toughness characteristics. Depending on the percentage of cobalt, carbide can be very brittle (grades C-2 and C-3) or highly durable with light impact strength (grades P-5 and P-6).
Grain size and composition play an important role in determining the carbide's hardness and other properties. Grades that have a higher percentage of binder metal and coarser tungsten carbide grain sizes tend to produce lower hardness values.
Various amounts of grain growth inhibitors are used to increase the fracture toughness of submicron and near-nano cemented carbides. The degree of the effect depends on the WC mean grain size, the amount of the grain growth inhibitors and their chemical composition.
During sintering, the sintering process binds the tungsten carbide grains with a metal binder, usually cobalt, to form a denser and harder product. Once the sintering is complete, the part can be machined using diamond wheel grinding or electrical discharge machining techniques.