Patent EP0185537A2 successfully refreshed from Google Patents.
EP0185537A2
Expired / Lapsed
EP
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Improvements in or relating to cutting structures for rotary drill bits
Assignee: Camco Drilling Group Ltd
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Filing: 1985-12-16
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Granted: —
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Expires: 2005-12-16
Abstract
Abstract A method of forming a cutting structure for a rotary drill bit comprises brazing a thermally stable polycrystalline diamond cutting element (10) to a carrier (11), the carrier being formed of a material such that. at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material. A suitable material is silicon carbide.
Inventors
- 👤 Michael Thomas Wardley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 21:57
CPC Classifications
B; B23; B23K; B23K31/00; B23K31/02; B23K31/025; B24; B24D; B24D3/00; B24D3/007; C; C04; C04B; C04B37/00; C04B37/003; C04B37/006; C04B2237/00; C04B2237/02; C04B2237/12; C04B2237/122; C04B2237/124; C04B2237/30; C04B2237/32; C04B2237/36; C04B2237/363; C04B2237/365; C04B2237/50; C04B2237/72; C04B2237/76
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
75 words
A method of forming a cutting structure for a rotary drill bit comprising brazing a thermally stable polycrystalline diamond cutting element (10) to a carrier, characterised in that the carrier (11) is formed of a material such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material.
Claim 2
Independent Claim
75 words
A method of forming a cutting structure for a rotary drill bit comprising brazing a thermally stable polycrystalline diamond cutting element (10) to a carrier, characterised in that the carrier (11) is formed of a material such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material.
Claim 3
Dependent Claim
35 words
A method according to Claim 1, characterised in that the difference in coefficient of thermal expansion between said carrier material and the polycrystalline diamond material is less than 3 x 10- 6 / o c.
Claim 4
Dependent Claim
15 words
A method according to Claim 2, characterised in that the carrier material is silicon carbide.
Claim 5
Dependent Claim
25 words
A method according to Claim 3, characterised in that the brazing material used to braze the cutting element to the carrier is a copper/phosphorus alloy.
Claim 6
Dependent Claim
25 words
A method according to Claim 3, characterised in that the brazing material used to braze the cutting element to the carrier is a germanium/silicon alloy.
Claim 7
Dependent Claim
14 words
A method according to Claim 5, characterised in that the germanium/silicon alloy includes titanium.
Claim 8
Independent Claim
36 words
A method according to any of Claims 1 to 6, characterised by the preliminary step, prior to brazing the cutting element to the carrier, of coating the cutting element with a material to facilitate the brazing.
Claim 9
Dependent Claim
32 words
A method according to Claim 7, characterised in that the material with which the cutting element is coated is a copper-based alloy including an element selected from crhomium, vanadium, titanium or boron.
Claim 10
Dependent Claim
45 words
A method according to Claim 7, characterised by the steps of applying the coating material to the surface of the cutting element by vapour deposition, and then heating the cutting element until the coating material reacts with the polycrystalline diamond material of the cutting element.
Claim 11
Dependent Claim
18 words
A method according to Claim 9, characterised in that the coating material is chromium, titanium, zirconium or silicon.
Claim 12
Independent Claim
27 words
A method according to any of Claims 1 to 10, characterised in that the cutting element comprises a flat circular disc of thermally stable polycrystalline diamond material.
Claim 13
Independent Claim
47 words
A method according to any of Claims 1 to 11, characterised in that the carrier comprises a substantially cylindrical stud (11, Figure 1a) having a flat surface inclined at an angle to the longitudinal axis of the stud, to which surface the cutting element (10) is brazed.
Claim 14
Dependent Claim
71 words
A cutting structure for a rotary drill bit including a thermally stable polycrystalline diamond cutting element (10) brazed to a carrier, characterised in that the carrier (11) is formed of a mterial such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material.
Claim 15
Dependent Claim
71 words
A cutting structure for a rotary drill bit including a thermally stable polycrystalline diamond cutting element (10) brazed to a carrier, characterised in that the carrier (11) is formed of a mterial such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond material is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material.
Claim 16
Dependent Claim
104 words
A rotary drill bit comprising a bit body having a shank for connection to a drill string and an inner channel for supplying drilling fluid to the face of the bit, the bit body carrying a plurality of cutting structures, characterised in that each cutting structure includes a thermally stable polycrystalline diamond cutting element brazed to a carrier, the carrier being formed of a material such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond materiel is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material.
Claim 17
Dependent Claim
104 words
A rotary drill bit comprising a bit body having a shank for connection to a drill string and an inner channel for supplying drilling fluid to the face of the bit, the bit body carrying a plurality of cutting structures, characterised in that each cutting structure includes a thermally stable polycrystalline diamond cutting element brazed to a carrier, the carrier being formed of a material such that, at the brazing temperature, the difference in coefficient of thermal expansion between said material and the polycrystalline diamond materiel is less than the difference in coefficient of thermal expansion between tungsten carbide and the polycrystalline diamond material.
References Cited (Backward Citations)
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