Pick tool

Patent metadata

Field	Value
Publication number	US-9097111-B2
Application number	US-201214114881-A
Country	US
Kind code	B2
Filing date	May 9, 2012
Priority date	May 10, 2011
Publication date	Aug 4, 2015
Grant date	Aug 4, 2015

Abstract

A pick tool for degrading asphalt or rock, comprising a PCD element; the PCD element comprising a PCD structure ( 20 ) bonded to a cemented carbide support body ( 30 ) at an interface; the PCD structure comprising a first region ( 24 ) and a second region ( 25 ) adjacent the first region, the second region bonded to the first region by intergrowth of diamond grains; the first region ( 24 ) comprising a plurality of alternating strata ( 24 c, 24 t ), each stratum having a thickness in the range of about 30 to 300 microns; the second region comprising a plurality of strata ( 25 a, 25 b ), one or more strata in the second region ( 25 a ) having a thickness greater than the thicknesses of the individual strata in the first region ( 24 c, 24 t ), wherein the alternating strata in the first region ( 24 ) comprise first strata alternating with second strata, the first strata being in a state of residual compressive stress and the second strata being in a state of residual tensile stress.

First claim

The invention claimed is:

1. A pick tool for degrading asphalt, comprising a PCD element; the PCD element comprising a PCD structure bonded to a cemented carbide support body at an interface; the PCD structure comprising a first region and a second region adjacent the first region, the second region bonded to the first region by intergrowth of diamond grains; the first region comprising a plurality of alternating strata, each stratum having a thickness in the range of 30 to 300 microns; the second region comprising a plurality of strata, one or more strata in the second region having a thickness greater than the thicknesses of the individual strata in the first region, wherein the alternating strata in the first region comprise first strata alternating with second strata, the first strata being in a state of residual compressive stress and the second strata being in a state of residual tensile stress; in which the PCD structure defines a working end including a rounded conical apex having a radius of curvature of 1.3 mm to 4 mm and is 2.5 mm to 10 mm thick from the apex to the interface.

2. A pick tool as claimed in claim 1 , in which each stratum has a thickness in the range of about 30 to 200 microns.

3. A pick tool as claimed in claim 1 , in which the strata in the second region have thickness of greater than about 200 microns.

4. A pick tool as claimed in claim 1 , in which the first region comprises three or more different average diamond grain sizes.

5. A pick tool as claimed in claim 1 , in which the strata in the second region comprise diamond grains having an average grain size substantially the same as the average grain size of the diamond grains in the first region.

6. A pick tool as claimed in claim 1 , in which the first strata are formed of a diamond mix having three or more different average diamond grain sizes and the second strata are formed of a diamond mix having the same three or more average diamond grain sizes, in which the first strata have a different ratio of diamond grain sizes in the mix from the second strata.

7. A pick tool as claimed in claim 1 , in which the first strata are formed of a diamond mix having a first average grain size and the second strata are formed of a diamond mix having a second average grain size.

8. A pick tool as claimed in claim 1 , in which strata in the first region comprise at most 20 weight per cent nano-diamond powder grains.

9. A pick tool as claimed in claim 1 , in which strata in the second region comprise at most 20 weight per cent nano-diamond powder grains.

10. A pick tool as claimed in claim 1 , in which strata in the first region comprise salt.

11. A pick tool as claimed in claim 1 , in which strata in the first region comprise borides or carbide compounds of at least one of Ti, V or Nb.

12. A pick tool as claimed in claim 1 , in which strata in the first region comprise at least one of the metals Pd or Ni.

13. A pick tool as claimed in claim 1 , in which strata in the second region comprise salt.

14. A pick tool as claimed in claim 1 , in which strata in the second region comprise borides or carbide compounds of at least one of Ti, V or Nb.

15. A pick tool as claimed in claim 1 , in which strata in the second region comprise at least one of the metals Pd or Ni.

16. A pick tool as claimed in claim 1 , in which the PCD structure has a longitudinal axis, the strata in the first region lying in a plane substantially perpendicular to the longitudinal axis.

17. A pick tool as claimed in claim 1 , in which the PCD structure has a longitudinal axis, the strata in the second region lying in a plane substantially perpendicular to the longitudinal axis.

18. A pick tool as claimed in claim 1 , in which at least some of the strata are substantially planar, curved, bowed or domed.

19. A pick tool as claimed in claim 1 , in which the PCD structure has a longitudinal axis, the strata in the first region lying in a plane at an angle to the longitudinal axis.

20. A pick tool as claimed in claim 1 , in which the PCD structure has a longitudinal axis, the strata in the second region lying in a plane at an angle to the longitudinal axis.

21. A pick tool as claimed in claim 1 , in which the volume of the first region is greater than the volume of the second region.

22. A pick tool as claimed in claim 1 , in which one or more of the strata intersect a working surface or side surface of the PCD structure.

23. A pick tool as claimed in claim 1 , in which each of the strata is formed of one or more respective PCD grades having a TRS of at least 1,200 MPa; the PCD grade or grades in adjacent strata having a different coefficient of thermal expansion (CTE).

24. A pick tool as claimed in claim 1 , in which one or more of the strata comprise a PCD grade having a CTE of at least 4 microns per degree centigrade.

25. A pick tool as claimed in claim 1 , in which a thermally stable region extends a depth of at least 50 microns from a surface of the PCD structure; the thermally stable region comprising at most 2 weight per cent of catalyst material for diamond.

26. A pick tool as claimed in claim 1 , in which the radius of curvature is 1.3 mm to 3.2 mm.

27. A pick tool as claimed in claim 26 , in which the PCD structure has a side forming a 35 degree to 55 degree angle with a central longitudinal axis of the PCD element.

Assignees

• Jonker Cornelis Roelof
• Bowes David Christian
• Shabalala Thembinkosi
• Can Nedret
• Element Six Abrasives Sa

Inventors

• Jonker Cornelis Roelof
• Bowes David Christian
• Shabalala Thembinkosi
• Can Nedret

Classifications

• B01J2203/068

  Crystal growth · CPC title

• B01J3/062

  characterised by the composition of the materials to be processed · CPC title

• B01J2203/062

  Diamond · CPC title

• E21C35/1837

  characterised by the shape · CPC title

• B25D2222/72

  Stone, rock or concrete · CPC title