The graphic illustrations below show that the mechanical properties of the carbide mainly depend on the binder content (Co) and the WC grain size. Hardness, i.e. wear resistance, increases inversely proportional to the fracture toughness. This means that the harder the material the more it reacts to notch tensions and impact stress (the impact resistance parameter, which cannot be precisely defined, correlates with the fracture toughness of the material). On the other hand, the transverse rupture strength does not directly depend on the hardness but rather on the WC grain size and the cobalt content. The adhesive wear (tendency to stick), however, decreases with the grain size and the cobalt content of the carbide used. The list of the mentioned interdependencies, which could be extended at will for other wear and failure mechanisms, show that it is only possible to choose the correct carbide grade following a systematic procedure and/or based on experience with similar applications.
