Which elements make difference to tungsten carbide grades
Straight tungsten carbide grades: containing only tungsten carbide and cobalt, are the strongest and most wear-resistant. Generally they are used for machining cast iron and nonmetals. The size of the tungsten carbide particles and the percentage of cobalt used determine the qualities of tungsten carbide tools:
- The finer the grain particles, the lower the tool toughness
- The finer the grain particles, the higher the tool hardness
- The higher the hardness, the greater the wear resistance
- The lower the cobalt content, the lower the tool toughness
- The lower the cobalt content, the higher the hardness
For maximum tool life, always select a tungsten carbide grade with the lowest cobalt content and the finest grain size possible that gives satisfactory performance without breakage
Crater-resistant grades: contain titanium carbide and tantalum carbide in addition to the basic components of tungsten carbide and cobalt. These grades are used for machining most steels.
The addition of titanium carbide provides resistance to tool cratering. The higher the titanium content, the greater is the resistance to cratering.
- As the titanium carbide content is increased, the toughness of the tool is decreased.
- As the titanium carbide content is increased, the abrasive wear resistance at the cutting edge is lowered.
- Tantalum carbide additions have effects similar to tungsten carbide on the resistance to cratering and strength.
- Tantalum carbide gives good crater resistance without affecting the abrasive wear resistance.
- The addition of tantalum carbide increases the tool’s resistance to deformation.