SUPER-HARD TIP FOR A PICK TOOL AND PICK TOOL COMPRISING SAME

• US 20140361601A1
• Filed: 12/12/2012
• Published: 12/11/2014
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Element Six Abrasives S.A (Element Six (Pty) Ltd.)
• Original Assignee: Element Six Bragance, Element Six Gmbh (Element Six (Pty) Ltd.)
• Inventors: Ries, Bernd Heinrich, Fries, Robert, Jonker, Cornelis Roelof, Bush, Peter
• Granted Patent: US 9,234,423 B2
• Time in Patent Office: Days
• US Class Current: 299/105
• CPC Class Codes: B28D 1/186 Tools therefor, e.g. having exchangeable cutter bits B28D1/181 takes precedence; bits for picks or pick-holders for mining or quarrying E21C35/18
• CPC Class Codes: E21B 10/56 Button-type inserts E21B10/52 takes precedence
• CPC Class Codes: E21C 35/18 Mining picks; Holders therefor planing knives E21C27/44
• CPC Class Codes: E21C 35/183 with inserts or layers of wear-resisting material drill bits with wear-resistant parts E21B10/46
• CPC Class Codes: E21C 35/1835 Chemical composition or specific material

Abstract

A strike tip for a pick tool, comprising a strike structure joined to a substrate at an interface boundary, the strike structure comprising super-hard material and the substrate comprising carbide material. The strike structure has a strike end opposite the interface boundary, the strike end including a rounded apex having a radius of curvature in a longitudinal plane of at least 3.2 mm and at most 6 mm.

Claims

1. A strike tip for a pick tool, comprising a strike structure joined to a substrate at an interface boundary, the strike structure comprising polycrystalline diamond (PCD) material and the substrate comprising carbide material;

the interface boundary being dome-shaped, defined by a convex proximate end boundary of the substrate having a radius of curvature in the longitudinal plane of 5 to 20 mm and being free of a central depression;

the strike structure having a strike end opposite the interface boundary, the strike end including a rounded apex having a radius of curvature in a longitudinal plane of at least 3.2 mm and at most 6 mm; and

the thickness of the strike structure between the apex and the interface boundary opposite the apex being 2.5 to 10 mm.

2. A strike tip as claimed in claim 1, in which the pick tool is for degrading road paving or rock formations in mining operations.

3. A strike tip as claimed in claim 1 or 2, in which the strike structure comprises polycrystalline diamond (PCD) material.

4. A strike tip as claimed in claim 1, in which the PCD material comprises diamond grains having a mean size of at least 15 microns.

5. A strike tip as claimed in any one of the preceding claims, in which at least a region of the strike structure adjacent at least a strike area of the strike end consists of PCD material containing filler material within the interstices between diamond grains, the content of the filler material being greater than 5 weight per cent of the PCD material in the region.

6. A strike tip as claimed in claim 5, in which the strike area includes the apex.

7. A strike tip as claimed in claim 5 or 6, in which the strike area extends over the entire strike end.

8. A strike tip as claimed in any one of the preceding claims, in which the strike structure consists of PCD material containing filler material in interstices between diamond grains, the content of the filler material being uniform throughout the strike structure.

9. A strike tip as claimed in claim 1, in which the strike end has the general form of a spherically blunted cone.

10. A strike tip as claimed in any one of the preceding claims, in which the interface boundary is generally dome-shaped, defined by a convex proximate end of the substrate having a radius of curvature in the longitudinal plane of at least 5 and at most 20 mm.

11. A strike tip as claimed in any one of the preceding claims, in which the thickness of the strike structure between the apex and the interface boundary opposite the apex is at least 2.5 mm and at most 10 mm.

12. A strike tip as claimed in claim 1, in which the height of the strike tip between the apex and a distal end of the strike tip substrate opposite the apex is at least 9 mm.

13. A strike tip as claimed in claim 1, in which the substrate comprises cemented tungsten carbide material including at least 5 weight per cent and at most about 10 weight per cent binder material comprising cobalt.

14. A strike tip as claimed in claim 1, in which the substrate comprises cemented carbide material having Rockwell hardness of at least 88 HRa, transverse rupture strength of at least about 2,500 MPa, magnetic saturation of at least 8 G.cm³/g and at most 16 G.cm³/g and coercivity of at least 6 kA/m and at most 14 kA/m.

15. A strike tip as claimed in claim 1, in which the strike structure comprises a plurality of grades of PCD material arranged as strata in a layered configuration, adjacent strata being directly bonded to each other by inter-growth of diamond grains.

16. A strike tip as claimed in any one of the preceding claims, in which the interface boundary includes a depression in the substrate opposite the apex of the strike structure.

17. A strike tip as claimed in claim 1, in which the substrate comprises an intermediate volume and a distal volume, the intermediate volume disposed between the strike structure and a distal volume and the intermediate volume being greater than the volume of the strike structure and comprising an intermediate material having a mean Young'"'"'s modulus at least 60% that of the super-hard material.

18. An assembly for a pick tool, in assembled, partially assembled or unassembled condition, comprising a strike tip as claimed in claim 1.

19. An assembly as claimed in claim 18, in which the strike tip is joined to a proximate end of an elongate support body, the support body being shrink fit within a bore provided within a steel base.

20. An assembly as claimed in claim 19, in which the support body comprises cemented carbide material including at least 5 weight per cent and at most 10 weight per cent binder material comprising cobalt.

21. An assembly as claimed in claim 20, in which the support body comprises cemented tungsten carbide material having Rockwell hardness of at least 90 HRa, transverse rupture strength of at least 2,500 MPa, magnetic saturation of at least 7 G.cm³/g and at most 11 G.cm³/g and coercivity of at least 6 kA/m and at most 11 kA/m.