CA1123822A

CA1123822A - Insert for tool wear surfaces and method of manufacture

Info

Publication number: CA1123822A
Application number: CA337,396A
Authority: CA
Inventors: Robert P. Radtke
Original assignee: NL Industries Inc
Current assignee: NL Industries Inc
Priority date: 1978-11-01
Filing date: 1979-10-11
Publication date: 1982-05-18
Also published as: FR2440245A1; GB2041427B; NO793434L; GB2041427A; FR2440245B1; NL7907924A

Abstract

INSERT FOR TOOL WEAR SURFACES
AND METHOD OF MANUFACTURE

ABSTRACT OF THE DISCLOSURE

An abrasion resistant insert for use in the wear surfaces of a tool body includes a body portion having pockets in its exposed face and a solid matrix formed into each pocket by powder metallurgy. Each matrix includes at least one hard, abrasion resistant particle, for example, a diamond. A method of manufacturing an insert includes the steps of filling the pockets in the body portion with carbide matrix powder having a hard particle disposed therein, placing a binder on the matrix powder and heating the matrix powder and binder to a temperature sufficient to melt the binder so that the binder infiltrates the matrix powder to form the solid matrix.

Description

~i238Z2 BACKGROUND O~ THE INVENTION

1. Field of the Invention The invention rela~es to abrasion resistant inserts for incorporation into wear surfaces of tools, for example, downhole oilfield tools such as drill string stabilizers.
In particular, the invention relates to inserts of the type incorporating exposed or flush hard particles such as dia-monds.

2. Description of the Prior Art It is well known that the wear surfaces of certain tools, for example, downhole oil field tools such as stabilizers, drill bits and roller reamers, may be provided with wear resistant inserts that reduce abrasive wear of the tool~
The inserts are usually press fit into openings in the tool body to provide areas having exceptional abrasion re~istance.
Inserts have been made from solid materials such as sin-tered tungsten carbide which are typically formed by well-known powder metallurgy techniqùes. It has also been proposed to include hard particles, for example, diamonds, into the 20 sintered carbide at the exposèd face of the insert to form an insert having improved abrasion resistance characteristics.
~owever, the manufacturé of such inserts, especially those including diamonds, has proven extremely costly~

3L~2:38~Z

SUMMARY O~ THE INVENTION

In accordance with the present invention there is pro-vided a novel insert for incorporation into the wear surface of a tool body. In a particular embodiment, the insert includes:
(a) a body portion having at least one pocket formed in its exposed surface; and ~b) a solid matrix formed in said at least one pocket and being intimately bonded to the 1~ pocket walls, said matrix including at least one hard particle.
The hard particle in each pocket may be a natural diamond which may be disposed substantially flush with the exposed surface of the insert body or may protrude from the exposed surface to effect cutting. A plurality of hard particles may be disposed in layers within each pocket. In a preferred embodiment, the body portion is formed as a cylinder having serrated edges facilitating press fitting of the body into a mating opening in the wear surface of a tool. According to 2~ this preferred embodiment, the exposed surface of the insert has a plurality of pockets disposed symmetrically along a circle concentric with the outer surface of the insert.
The body portion may be formed by powder metallurgy from a carbide powder such as tungsten carbide or may be formed from other materials such as tool ~teel. Furthermore, the body may comprise an inner body coated with a coating such as titanium carbonitride.

.

In accordance with the present invention there is also provided a novel method of manufacturing an insert from an insert body having at least one pocket in its exposed sur-face which comprises the steps of:
(a) filling the pocket with a matrix powder having at least one hard particle disposed within the matrix pouder;
(b) placing a binder proximate the matrix powder; and ~ (c) heating said matrix powder and binder to a temperature sufficient to melt the binder so that the binder infiltrates the matrix powder.
Accordingly, it is a principle feature of the present invention to provide an insert adapted for press fitting into an opening in the wear surface of a tool to enhance the wear resistance of the tool surface. The insert may comprise a relatively abrasion resistant body portion adapted for press fitting into a mating opening in the tool wear surface. Poc-~ kets are formed in the exposed surface of the insert forholding hard particles, such as diamonds, in place to enhance the abrasion resistance characteristics of the wear surface.
It is a further feature of the present invention to provide an insert having an exposed surface with pockets wherein the pockets are filled with a carbide matrix powder having at least one hard particle disposed therein. The matrix powder is furnaced within the pocket by powder metal-lurgy techniques. One aspect of this feature is that a binder such ~s a copper alloy may infiltrate the matrix powder ::A

~L~IL23~3Z2 during the furnacing operation to provide a solid matrix in intimate contact with the walls of the pocket.
It is still a further feature of the present invention to provide a method of manufacturing an insert wherein the insert body pockets are filled with a carbide matrix powder having diamonds disposed therein and the matrix powder and binder are furnaced at a temperature below that which causes thermal damage to the diamonds.
Still further advantages and meritorious features of the present invention will become apparent from the follow-ing more detailed description.

Z382~

BRIEF DESCRIPTION OF T~E DRAWINGS

Figure 1 is a plan view of the insert body portion.
Figure 2 is a section view taken substantially along line 2-2 of Figure 1.
Figure 3 is an enlarged view of one pocket in-the insert body showing the carbide matrix powder, a diamond and the binder in place prior to furnacing.
Figure 4 shows the pocket of Figure 3 after furnacing.
Figure 5 is a view similar to Figure 4 showing a pocket containing a solid matrix with two diamonds disposed in layers.
Figure 6 is a view similar to Figures 4 and 5 showing a pocket containing a solid matrix with a large number of small diamonds.
Figure 7 is a view similar to Figures 4, 5 and 6 showing a pocket containing a solid matrix with a diamond protruding above the matrix to effect cutting.
Figure 8 is a view of a blade type stabilizer whic~
utili~es different types of inserts, some of which are manu-factured in accordance with the present invention.

3~2Z

DETAILED D~SCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention will now be described with reference to Figures 1-4. Figure 1 is a top view of the insert body utilized in accordance with the present invention. Insert body 10 is substantially cylin~
drical in shape and includes a planar exposed surface 12 which is adapted to substantially form a continuation of the wear surface of a tool when the body 10 is press fit into a mating opening in the tool wear surface. Body 10 further includes cylindrical sidewall portion 16, a substantially flat base 18 and a beveled ring surfaces 22 and 23 connecting the sidewall to the base. Sidewall 16 is preferably formed with a serrated edge comprising protrusions 26 and recesses 30. The serrations facilitate the press fitting of the insert body into a mating opening in the wear surface whereby the material of the tool body, typically steel t may be deformed into the serrations to form an integral lock.
As best shown in Figure 2, an upper tapered ring portion 34 and a circular lip 36 are provided where expo~ed surface 12 meets sidewall 16.

In the illustrated embodiment, exposed surface 12 includes a ring of five pockets 40 which are symmetrically disposed along a circle concentric with the outer surface of body 10.
An inner pocket 44 is formed at the center of the concentric -circles. The spacing between the pockets and the configuration and location of the pockets are not critical provided there is ample space between the pockets so that the structural integ-rity of the body 10 is not affected.

~Li23~32Z

Figure 3 illustrates a single pocket 44 filled with a carbide matrix powder 50, a single, substantially cube-shaped diamond 52 and covered by a binder 56 prior to furnacing of the matrix powder. In a preferred manner of practicing the invention, the matrix powder is a t~ngsten carbide powder.
Binder 56 is selected so that it melts before reaching the maximum furnace temperature and thereby infiltrates the matrix powder in the manner known in the art to form a solid matrix that serves as the continuous phase for supporting the hard 10 particle. In a preferred embodiment, the binder 56 is a cop-per alloy, for example, No. 16 binder manufactured by Entectic Corporation. In the embodiment illustrated in Figure 3, the hard particle contained within the matrix is a single natural diamond 52 which may have a size on the order of 1/10 carat.
Diamond 52 is disposed within the matrix powder su~stantially flush with the exposed surface 12.
In the illustrated embodiment, insert body 10 has a diameter of approximately 9/16 inch and a height of approxi-mately 3/8 inch. This is a standard sized insert for many downhole oil field tool applications; however, other insert sizes, e.g., 3/8 inch diameter, are utilized. Each pocket 40, 44 has a diameter of approximately 0.10 inch and a depth which may vary but, as illustrated, is on the order of 0.20 inch. Diamond 52 illustrated in Figures 3 and 4 is approxi-mately 0.08 inch on a side. Therefore, it can be seen that the upper face 57 of diamond ~ occupies a major portion o~
the exposed portion of pocket 4~. In this case, is desired that diamond face 57 occupy an area in excess o~ 1/2 of the exposed pocket. The primary purpose of the sGlid matrix 50 ~z3~;~2 is to serve as the continuous phase for holding the hard particle, e.g., diamond 52r in place. Therefore, it will be desirable in many applications to utill~e a diamond having a face that will occupy most of the exposed pocket surface, for example, diamond faces occupying up to 90% of even more of the pocket surface. It will be appreciated that irregular shaped diamonds, particularly irregular shaped diamonds having one substantially flat face, may be utilized in place of more uniform cube-shaped diamonds. It will also be appreciated that in the embodiment illustrated in Figures 1-4 the body 10 is considerably harder than solid matrix 50;
therefore, the enhanced abrasion resistant characteristics are provided by the diamond face and not by the solid matrix 50.
A method of manufacturing an insert in accordance with the pxesent invention will now be described with further reference to Figures 1-4. As stated previously, the insert body may be a cemented carbide body formed by powder metall-urgy from, for example, a tungsten carbide powder. The body may also be formed from other powders, e.g~, other carbide powders, or rom other materials such as tool steel. In a particular method of manufacturing an insert body for use with the present inven-tion, the body 10 is manufactured by conventional cold pressing and sintering powder metallurgy techniques. More particularly, a tungsten carbide powder including wax and a binder, for example, cobalt, are cold pressed to shape in a steel dye. The body so formed is next ejected from the dye and is held together at this point by the wax. The body i5 next placed in a dewaxing furnace to drive off the wax at approximately ~00F and then sintered at 3000-3200F whereby the binder, for example, cobalt, g _ ~238~Z

becomes molten to fully densify the material. At this point, the cemented carbide insert body 10, including pockets 40 and 44, is complete and ready to receive the matrix powder and hard particles within each pocket. I-t should be pointed out that the body portion 10 may be made by numerous -techniques, including solid-phase or liquid-phase sintering powder metall-urgy techniques, and that the primary requirement of the body portion is that it have acceptable abrasion resistant charac-teristics, acceptable compressive strength and reasonably high hardness, for example, in the case of a cemented tungsten carbide insert body, a hardness on the order of a Rockwell A
hardness index of 90. When body 10 is a cemented carbide body formed by powder metallurgy, the powder may be othex than tungsten carbide, for example, titanium carbide, vanadium carbide, or a mixture of vanadium carbide and molybdenum carbide. A further means of forming the body is to form the body in two parts comprising an inner body coated with a solid coating such as titanium carbonitride.
After the insert body 10 has been formed with pockets such as pockets 40 and 44, a matrix powder such as tungsten carbide matrix powder is placed within each pocket with a selected number of hard particles disposed within the powder at desired points. Preferably, the matrix powder is chosen so that it will shrink during furnacing somewhat less than the shrinkage of -the body so that the body will shrink around the matrix powder~as it is densified to a solid matrix. The matrix powder is chosen such that after furnacing it will have good impact strength to prevent fractures and will have good wear characteristics so that it will not wash out around ` ~LZ3~322 the hard particles. In order to assure that the matrix powder has properly settled within the pocket prior to furnacing, the insert body may be vibrated.
A binder, for example a copper alloy, is next placed on top of each pocket containing the matrix powder and hard par-ticles. In a preferred manner of practicing in the invention, the binder is selected as a copper alloy No. 16 binder manu-factured by Entectic Corporation. It is preferable that the binder be one that will melt at a temperature below approxi-mately 2200F since natural diamonds will sustain structuraldamage when the diamond is subjected to temperatures essenti-ally in excess of 2200F. A sufficient amount of binder should be placed over each pocket so that when melted the binder will fully infiltrate the matrix powder to give maximum infiltration and maximum density of the final solid matrix. Therefore, pre-ferably an excess of binder is placed above each pocket to ensure maximum infiltration. The binder that melts and does not infiltrate will remain on exposed surface 12. In order to prevent excess melted binder from covering the sidewall 16, a dam (not shown) or other means may be constructed around the perphery of the tool body, for example, at llp 36. An alter-native method of keeping the excess melted binder off of the sidewalls is to coat the sidewall surfaces with a protective coating such as STOP-OFF brand protective coating manufactured by Wall Colmonoy of Detroit, Michigan.
Furnacing of the material within the insert pockets is accomplished at a temperature below 2200F when diamonds are used to constitute all or a part of the hard particles. In a preferred method of practicing the invention with diamonds .

~11--~3~2~

utilized as the hard particles, the insert pockets containing a tungsten carbide powder matrix is furnaced for ten minutes at 2150F utilizing the No. 16 Entectic copper alloy as a binder. It will be appreciated that adequate infiltration of certain binders with various matrix powders can be achieved within a range of approximately 1650F to 2200F without appreciable damage to the structure of natural diamonds. Fur-thermore, it will be appreciated that with the use of other hard particles the furnacing cycle may take place within a 10 temperature range above 2200F.
During furnacing it has been found that the hard par-ticles, for example, diamonds, may tend to float within the matrix powder as it is being infiltrated by the binder.
Therefore, it may be desirable to place a weight or other fix-turing means on the hard particles during furnacing.

~L~23822 ALTE~NATIVE EMBODIMENTS

A first alternative embodiment o~ an insert constructed in accordance with the present invention will be described with reference to Figure 5. Figure 5 illustrates a pocket 44 ~ormed in the insert body wherein a pair of natural, substan-tially cube-shapped diamonds 60, 62 are disposed in layers within the matrix powder. It will be appreciated that during use of tools having wear surfaces incorporating the inserts of the present invention, the wear surface and the insert exposed surface 12 will gradually erode. During this erosion I0 the matrix material 50 withi`n the pockets will also wear down.
Therefore, it may be desirable in some applications to have the hard particles within the pockets disposed in layers so - that when the first layer is worn away another layer will be present to slow the further erosion of the wear surface. It will be appreciated that each layer within the pocket may include more than one hard particles although the embodiment illustrated in Figure 5 includes only one hard particle, a substantially cube-shaped diamond, in each layer.
Figure 6 illustrates a second alternative embodiment of the invention wherein a very large number of hard particles, for example small diamonds 66, are disposed within the matrix.
The so-called "diamond impregnated matrix~ strated in Figure ~ may be used in certain applications to give uniform wear resistant characteristics to the matrix material from the top to the bottom of the pocket.
A third alternative embodiment is illustrated in Figure 7 wherein a single diamond 70 is disposed within the matrix 3~Z2 so as to protrude above the exposed surface 12. This embodi-ment may be utilized where the tool into which the insert is press fit is utilized to perform cutting. In one embodiment with a pocket having a diameter of 0.10 inch it has been found desirable to have the diamond protrude approximately 0.06 inch.

APPLICATIONS OF THE INVENTION

It will be appreciated that inserts manufactured in accordance with the present invention will have application in numerous tools. For example, as shown in Figure 8, a near-bit stabilizer 80 may include three different kinds of inserts.
In the areas designated by reference character A, the inserts on the stabilizer blades are formed with pockets having single diamonds which protrude above the surface of the stabilizer blade as shown, for example, in Figure ~. It will be appre-ciated that the inserts fo~nd in areas A protrude above the stabilizer blade in order to efect cutting at the end por-tions of the blade.
The inserts located in the stabilizer blades in the areas designated by reference character B include pockets having single cube-shaped diamonds which lie flush against the stabi-lizer blade surface as shown, for example, in Figure 4. The inserts in areas B are intended to reduce abrasion without effecting appreciable cutting.
The inserts located on the stabilizer blades in the area designated by reference character C are conventional solid tungsten carbide inserts having no hard particles. These inserts reduce abrasive wear in area C but are not provided with pockets for including hard particles such as diamonds.

3~22 It will be appreciated by those skilled in the art that inserts manufactured in accordance with the present invention may be utilized on other types of drill string stabilizers, on the gauge of drill bits, on roller reamers, and on tool joints and other drill string components. It will also be appreciated that the inserts may be used in mining applica~
tions anywhere there is a wear surface where wear is to be reduced. In general, the invention has application for use as an abrasion resistant element on any body having a surface exposed to abrasive wear conditions.
While the present invention has been disclosed in connec-tion with several illustrated embodiments, it will be apparent to those skilled in the art that numerous modifications may be made without departing from the spirit or scope of t~e present invention. For example, the pockets may incorporate hard par-ticles other than natural diamonds, e.g.,synthetic polycry-stalline diamonds. Furthermore, it will be appreciated that the shape of diamonds utilized within the pockets may be selected according to the particular use of the insert. Typ-ical commercial diamond shapes, e.g., round, tetragonal andcube, may be utilized as well as other shapes. Furthermore, diamonds of different qualities may be used. Also, diamonds having surfaces treated chemically or mechanically may be used in certain applications. While it has been disclosed that the inserts are ~press fit~ into openings in a wear surface, it will be appreciated that the term ~press fit" is deemed to include any means of forcibly inserting the insert into a mating opening, for example, by hammering or by pressing at variable forces. These and other ~arlations are within the ~ spirit and scope of the present invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An insert having sidewalls for engaging a mating opening in a wear surface by press fitting, and having an exposed surface for forming substantially a continua-tion of the wear surface, said insert comprising:
A body portion defining the sidewalls and exposed surface, said body portion having at least one pocket formed in its exposed surface; and a continuous-phase, solid matrix formed in each pocket of said body portion by densification of a matrix powder with a molten binder, each matrix containing a least one hard, abrasion resistant particle, and said binder having a melting point below said matrix powder and said particle, to allow said binder to infiltrate said matrix powder to form said solid continuous-phase matrix, and bond said solid matrix to the pocket walls.

2. An insert as claimed in claim 1 wherein said hard particle is a natural diamond.

3. An insert as claimed in claim 2 wherein said diamond includes a substantially flat surface located proximate the exposed surface.

4. An insert as claimed in claim 1 wherein said matrix includes a plurality of hard particles arranged in layers.

5. An insert as claimed in claim 4 wherein said particles are natural diamonds.

6. An insert as claimed in claim 1 wherein said insert includes serrated sidewall surfaces facilitating press fitting of the insert into a mating opening in a wear surface.

7. An insert as claimed in claim 6 wherein said sidewall surfaces are cylindrical.

8. An insert as claimed in claim 7 wherein said body portion exposed surface includes a plurality of pockets disposed symmetrically along a circle concentric with the outside surface of the insert.

9. An insert as claimed in claim 1 wherein said body portion is formed by powder metallurgy from a carbide composition.

10. An insert as claimed in claim 9 wherein said carbide composition comprises tungsten carbide.

11. An insert as claimed in claim 9 wherein said carbide composition comprises titanium carbide.

12. An insert as claimed in claim 9 wherein said carbide composition comprises vanadium carbide.

13. An insert as claimed in claim 9 wherein said carbide composition comprises a mixture of vanadium carbide and molybdenum carbide.

14. An insert as claimed in claim 1 wherein said body portion comprises tool steel.

15. An insert comprising:
a body portion having at least one pocket formed in its exposed surface, said body portion comprising an inner body coated with a solid coating;
and a matrix formed in said at least one pocket and being intimately bonded to the pocket walls, said matrix including at least one hard particle.--

16. An insert as claimed in claim 15 wherein said coating comprises titanium carbonitride.

17. An insert for use as an abrasion resistant element press fit into a wear surface comprising:
a solid body portion comprising a substantially fully densified powder, said body portion being sized to be press fit into a mating opening in the wear surface, said body portion having an exposed surface which, after press fitting, substantially forms a continuation of the wear surface, said exposed surface having at least one pocket formed therein; and a continuous-phase, solid matrix formed in said at least one pocket by densification of a matrix powder with a molten binder, said binder having a melting point below said matrix powder, to allow said binder to infiltrate said matrix powder to form said solid continuous-phase matrix, said solid matrix being intimately bonded to the pocket walls and including at least one hard particle.

18. An insert as claimed in claim 17 wherein said hard particle is a natural diamond.

19. A method of manufacturing an insert for press fitting into a mating opening in a wear surface, comprising the steps of:
forming an integral insert body having a substan-tially planar exposed surface which, after press fitting, substantially forms a continu-ation of the wear surface, the exposed surface being formed with at least one pocket therein;
said step of forming the insert body being performed by a powder metallurgy technique comprising shaping a powder into a shape approximately the shape of the finished body and densifying the shaped powder by liquid-phase sintering;
filling the pocket with a matrix powder having at least one hard particle disposed within the matrix powder;
placing a binder, having a melting point below said matrix powder, proximate the matrix powder; and heating the matrix powder and binder to a tempera-ture sufficient to substantially melt the binder, so that the binder infiltrates the matrix powder to form a continuous-phase, solid matrix in intimate contact with the pocket walls and serving to hold the hard particle in place.

20. A method of manufacturing an insert for press fitting into a mating opening in a wear surface, comprising the steps of:
forming an insert body having a substantially planar exposed surface which, after press fitting, substantially forms a continuation of the wear surface, the exposed surface being formed with at least one pocket therein;
said step of forming the insert body being performed by a powder metallurgy technique comprising shaping a powder into a shape approximately the shape of the finished body and densifying the shaped powder by liquid-phase sintering;
filling the pocket with a matrix powder having at least one hard particle disposed within the matrix powder;
placing a binder proximate the matrix powder; heating the matrix powder and binder to a temperature sufficient to substantially melt the binder so that the binder infiltrates the matrix powder to form a continuous-phase, solid matrix in intimate contact with the pocket walls and serving to hold the hard particle in place;
the liquid-phase sintering used in forming the body is conducted at temperatures in excess of 2200°F;

said hard particle is a diamond; and said temperature sufficient to substantially melt the binder is below 2200°F.--

21. A method as claimed in claim 19 wherein said hard particle is disposed within the matrix powder substantially flush with the body exposed surface.

22. A method as claimed in claim 19 wherein said hard particle is disposed within said matrix powder to protrude above the body exposed surface.

23. A method as claimed in claim 19 wherein a plurality of hard particles are disposed in layers within the matrix powder.

24. A method of manufacturing an insert from an insert body having a substantially planar exposed surface which, after press fitting into a wear surface, substantially forms a continuation of the wear surface, the exposed surface being formed with at least one pocket therein comprising the steps of:
filling the pocket with a carbide containing matrix powder having at least one diamond disposed within the matrix powder;
placing a binder having a melting temperature below the thermal degradation temperature of diamonds proximate the matrix powder; and heating the binder to a temperature sufficient to melt the binder so that the binder infiltrates and fully densifies the matrix powder to form a continuous-phase, solid matrix in intimate contact with the pocket walls and serving to hold the diamond in place.

25. A stabilizer having a plurality of blades for wipingly engaging a bore hole, each of said blades including at last one opening sized to receive a composite wear resistant, mating insert, at least some of said openings including said composite inserts comprising:
a body portion defining sidewalls and an exposed surface, said sidewalls engaging the blade openings and said exposed surface forming substan-tially a continuation of the blade surface;
said body portion having at least one pocket formed in its exposed surface; and a continuous-phase, solid matrix formed in said pocket by densification of a matrix powder with a molten binder, said solid matrix being intimately bonded to the pocket walls and including at least one hard particle.

26. An insert of the type having sidewalls for engaging a mating opening in a wear surface by press fitting, and having an exposed surface for forming substantially a con-tinuation of the wear surface, said insert comprising:
a body portion defining the sidewalls and exposed surface, said body portion having at least one pocket formed in said exposed surface; and a continuous-phase, solid matrix bonded to each of said pockets by densification of the matrix powder with a molten binder, each matrix con-taining at least one diamond, and said molten binder having a melting temperature below the thermal degradation temperature of diamonds and said matrix powder.