Drill bits comprising dual-phase tungsten carbide material
View Patent ↗The invention relates to a drill bit containing tungsten carbide powder having powder particles which have a core of cast tungsten carbide and a shell of tungsten monocarbide.
1. A drill bit which comprises a tungsten carbide powder which consists essentially of powder particles which have a core of cast tungsten carbide and a shell of tungsten monocarbide.
2. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a bound carbon content of 4 to 6 wt. %.
3. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a bound carbon content of 4.5 to 5.5 wt. %.
4. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a bound carbon content of 4.3 to 4.8 wt. %.
5. The drill bit as claimed in claim 4 , wherein the tungsten carbide powder has a free carbon content that does not exceed 0.1 wt. %.
6. The drill bit as claimed in claim 5 , wherein the tungsten carbide powder has a hardness of >2500 HVO.1 and the thickness of the shell of tungsten monocarbide is 0.05 to 0.4 times the average particle size.
7. The drill bit as claimed in claim 6 , wherein the tungsten carbide powder have particles which have a sharp-edged crushed morphology.
8. The drill bit as claimed in claim 6 , wherein the tungsten carbide powder have particles which have a spherical morphology.
9. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a free carbon content that does not exceed 0.1 wt. %.
10. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a particle size determined by Ro-Tap sieve analysis in accordance with ASTM B 214 is up to 3000 μm.
11. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a thickness of the shell of tungsten monocarbide that is 0.05 to 0.4 times the average particle size.
12. The drill bit according to claim 1 , wherein the tungsten carbide powder has a hardness of >2000 HVO.1.
13. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder has a hardness of >2500 HVO.1 and the thickness of the shell of tungsten monocarbide is 0.05 to 0.4 times the average particle size.
14. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder have particles which have a sharp-edged crushed morphology.
15. The drill bit as claimed in claim 1 , wherein the tungsten carbide powder have particles which have a spherical morphology.