Camco International, Inc.

Schlumberger Technology Corporation

Camco International (uk) Limited

Harold A Sreshta

Eric F Drake

Nigel Dennis Griffin

A method of thermally treating a preform element, of the kind having a facing table of polycrystalline diamond bonded to a substrate of cemented tungsten carbide, comprises the steps of: (a) heating the element to a soaking temperature of 550-625&deg; C., and preferably about 600&deg; C., (b) maintaining the element at that temperature for at least one hour, and (c) cooling the element to ambient temperature. The resulting preform element has a substrate with a cobalt binder including a substrate interface zone with at least 30 percent by volume of the cobalt binder a hexagonal close packed crystal structure. This reduces the risk of cracking or delamination of the element in use.

Methods of treating preform elements

The present invention relates to a method of forming a powder rod core comprising injecting a powder mix material into a mold, moving the mold to a curing station, and injecting material into a second mold.

Fabrication process for powder composite rod

The present invention is a new method for forming a high density hard facing rod. The rod is particularly suitable for hardfacing downhole tools including both fixed cutter and rolling cutter drill bits, bias pads for downhole rotary steerable systems, and stabilizers, and for other types of tools requiring strong and wear resistant hardfacings. The method includes the steps of: preparing a powder mix comprising carbide and metal powders, a fugitive binder, and other additives to render a moldable rheology; forming the powder mix into a powder core encased with a metal sheath to form a core-sheath assembly; and isostatically compacting the core-sheath assembly to densify the core to at least 65% of theoretical density and mechanically attach the sheath. The core fugitive binder along with residual volatile constituents may be thermally removed with or without vacuum, reducing, or inert environment prior to weld application of the composite rod.

Fabrication process for high density powder composite hardfacing rod

Methods of forming a new wear and abrasion overlay formed with the steel surfaces of components for earth boring bits, and the components formed by the methods are disclosed. The overlay comprises a hard material particulate containing a metal carbide and an alloy steel matrix. The volume fraction of the hard material particulate in the overlay is greater than about 75%, the average particle size of the hard material particulate is between about 40 mesh and about 80 mesh, and the thickness of the overlay is less than about 0.050 inches. The process of manufacture includes the steps of fixing a monolayer of hard material particulate to the surface of a flexible mold, filling the mold with materials and powders, and CIP densifying to form a preform. The preform is then forged to near 100% density in a rapid solid state densification powder metallurgy process. The resulting bit component has an integrally formed overlay with superior physical properties.

Rock bit hardmetal overlay and proces of manufacture

A steel tooth rolling cutter earth boring drill bit includes a bit body with a threaded upper end for attachment to the end of a drill string, and a lower end including three legs extending downwardly from the bit body and with a rolling cutter rotatably mounted on each leg. A layer of wear resistant material is applied to a portion of each rolling cutter and comprises wear resistant particles in a substantially steel matrix. The steel matrix is integrally formed with the cutter in a rapid, solid state densification powder metallurgy (RSSDPM) process, and includes a duplex microstructure comprising from about 10 to 40 volume percent austenite and from about 60 to 90 volume percent martensite. The duplex microstructure may be achieved by incorporating a minor fraction of pure nickel and/or manganese powder in the powder mix used in the process, thereby providing nickel or manganese enrichment of the austenitic zones of the matrix.

Hardmetal facing for earth boring drill bit

Rock bit hardmetal overlay and process of manufacture

A steel tooth rolling cutter earth boring drill bit comprises a bit body with a threaded upper end for attachment to the end of a drill string, and a lower end comprising three legs extending downwardly from the bit body and with a rolling cutter rotatably mounted on each leg. A layer of wear resistant material is applied to a portion of each rolling cutter and comprises were resistant particles in a substantially steel matrix. The steel matrix is integrally formed with the cutter in a rapid, solid state densification powder metallurgy (RSSDPM) process, and comprises a duplex microstructure comprising from about 10 to about 40 volume percent austenite and from about 60 to 90 volume precent martensite. The duplex microstructure may be achieved by incorporating a minor fraction of pure nickel and/or manganese powder in the powder mix used in the process, thereby providing nickel or manganese enrichment of the austenitic zones of the matrix.

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Houston, TX, United States of America

Harold A Sreshta