Hardfacing composition for earth-boring bits

a technology of earthboring bits and compositions, applied in the field of earthboring bits hardfacing compositions, can solve the problems of premature cracking and flaking of hardfacing, inadequate hardness and wear resistance, premature eroded hardfacing, etc., and achieve good wear resistance and fracture toughness.

Inactive Publication Date: 2001-04-10
BAKER HUGHES INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

It is a general object of the present invention to provide an improved hardfacing for use in earth-boring bits and other applications having a need for good wear resistance in combination with good fracture toughness.

Problems solved by technology

A hardfacing composition that is extremely hard and wear-resistant may lack fracture toughness, causing the hardfacing to crack and flake prematurely.
Conversely, a hardfacing with adequate fracture toughness, but inadequate hardness and wear resistance, is eroded prematurely and fails to serve its purpose.

Method used

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  • Hardfacing composition for earth-boring bits

Examples

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example

The following quantities and sizes of granular carbide materials were provided:

Spherical sintered tungsten carbide pellets comprising tungsten carbide particles or grains sintered with a 6% by weight cobalt binder and provided by Kennametal, Inc. of Fallon, Nev., in the following sizes and percentages by weight:

ASTM Mesh Size Range Mean +16 0-5% 3% -16 / +20 40-50% 47% -20 / +30 40-50% 47% -30 0-5% 3%

Crushed sintered tungsten carbide, also provided by Kennametal, Inc., in the following sizes and percentages by weight:

ASTM Mesh Size Range Mean +20 0-5% 3% -20 / +30 90-100% 94% -30 0-5% 3%

Spherical cast carbide pellets, manufactured by WOKA Schweisstechnik GmbH, of Willich, Germany, in the following sizes and percentages by weight:

ASTM Mesh Size Range Mean +40 0-5% 3% -40 / +60 90-100 94% -60 0-5% 4%

The carbide granules were blended, by tumbling in a barrel mill, together with 4% by weight silicomanganese, 0.5% by weight niobium and 0.36% by weight resinox. After the initial blending, alcohol...

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Abstract

A hardfacing composition comprises at least 60% by weight of hard metal granules including a quantity of sintered carbide pellets and a quantity of cast carbide pellets. The cast and sintered carbides are selected from the group of carbides consisting of chromium, molybdenum, niobium, tantalum, titanium, tungsten, and vanadium carbides and alloys and mixtures thereof. The balance of the hardfacing composition is matrix metal with traces of flux or deoxidizer, and alloying elements. All percentages given are pre-application ratios.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to the composition of hardfacing materials applied to surfaces subjected to abrasive wear to increase their wear resistance. More particularly, the present invention relates to hardfacing compositions applied to one or more surfaces of an earth-boring bit of the rolling cutter variety.2. Background InformationIt is a long-standing practice in the design and manufacture of earth-boring bits to apply wear-resistant hardfacing materials to the surfaces of such bits that are subjected to abrasive wear during drilling operations. In earth-boring bits of the rolling cutter variety, these surfaces include the teeth of bits of the milled or steel tooth variety, the gage surfaces of the rolling cutters, and the shirttails of the bit legs comprising the bit body.In the past, these hardfacing compositions generally comprise carbides of the elements of Groups IVB, VB, and VIB in a matrix metal of iron, cobalt, or ...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): B23K35/32B23K35/24C22C1/05C23C4/10E21B10/46E21B10/50B22F1/12B22F1/148C23C30/00
CPCB22F2999/00B23K35/327C22C1/051C23C4/10C23C30/005E21B10/50B22F9/04C22C29/08C22C33/02B22F1/148B22F1/12B22F1/065B22F3/10C22C29/06B22F9/082
Inventor SCHADER, KEVIN W.OVERSTREET, JAMES L.MASSEY, ALAN J.JONES, RONALD L.SCOTT, DANNY E.
Owner BAKER HUGHES INC
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