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Hardfacing having coated ceramic particles or coated particles of other hard materials

Imported: 23 Feb '17 | Published: 22 Oct '02

James Edward Boyce

USPTO - Utility Patents

Abstract

Hardfacing to protect wear surfaces of drill bits and other downhole tools having coated cubic boron nitride particles or coated particles of other ceramic, superabrasive or superhard materials dispersed within and bonded to a matrix deposit. The coating on the ceramic particles or particles of other hard materials may be formed from materials and alloys such as tungsten carbide, and tungsten carbide/cobalt and cermets such as metal carbides and metal nitrides. The coated particles are preferably sintered and have a generally spherical shape. The coated particles are pre-mixed with selected materials such that welding and cooling will form both metallurgical bonds and mechanical bonds within the solidified matrix deposit. A welding rod may be prepared by placing a mixture of selected hard particles such as coated cubic boron nitride particles, hard particles such as tungsten carbide/cobalt, and loose filler material into a steel tube. A substrate may be hardfaced by progressively melting the welding rod onto a selected surface of the substrate and allowing the melted material to solidify and form the desired hardfacing with coated cubic boron nitride particles dispersed within the matrix deposit on the substrate surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its advantages thereof, reference is now made to the following brief description, taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts, in which:

FIG. 1 is an enlarged schematic drawing in section with portions broken away showing a coated hard particle such as a coated cubic boron nitride particle dispersed within and bonded to a matrix deposit in accordance with teachings of the present invention;

FIG. 2 is a schematic drawing in section with portions broken away showing a coated hard particle such as a coated cubic boron nitride particle dispersed within and bonded to a matrix deposit to form hardfacing on a substrate in accordance with teachings of the present invention;

FIGS. 3A and 3B are schematic drawings in elevation and in section with portions broken away showing a hollow welding rod with a filler having coated hard particles such as coated cubic boron nitride particles and other hard materials disposed therein in accordance with teachings of the present invention;

FIG. 4 is a schematic drawing in section and in elevation showing a drill bit with hardfacing formed in accordance with the teachings of the present invention at a downhole location in a wellbore;

FIG. 5 is a schematic drawing in elevation showing another type of drill bit with hardfacing formed in accordance with teachings of the present invention;

FIG. 6 is a drawing partially in section and partially in elevation with portions broken away showing a cutter cone assembly and support arm of the rotary cone bit of FIG. 5 having layers of hardfacing formed in accordance with teachings of the present invention;

FIG. 7 is a drawing partially in section and partially in elevation with portions broken away showing the cutter cone assembly and support arm of FIG. 6 with additional layers of hardfacing formed in accordance with the teachings of the present invention;

FIG. 8 is a schematic drawing showing an isometric view of a rotary cone drill bit having milled teeth with layers of hardfacing formed in accordance with teachings of the present invention;

FIG. 9 is an enlarged, schematic drawing partially in section and partially in elevation with portions broken away showing a support arm and cutter cone assembly with milled teeth having layers of hardfacing formed in accordance with teachings of the present invention; and

FIG. 10 is an isometric drawing with portions broken away showing a milled tooth covered with a layer of hardfacing incorporating teachings of the present invention.

Claims

1. A welding rod for use in forming a layer of hardfacing on a substrate to protect the substrate from abrasion and wear, comprising:

2. A welding rod comprising:

3. A welding rod for use in forming a layer of hardfacing on a substrate to protect the substrate from abrasion and wear, comprising:

4. The welding rod of claim 3, further comprising carbon nitride particles mixed with the coated hard particles.

5. The welding rod of claim 3, wherein the sintered coating on the selected hard particles further comprises tungsten carbide.

6. The welding rod of claim 3, further comprising: