Patent Application
20070277646
The following is a brief description of the drawings which form a part of this patent application:
Referring to
A steel shank 24 is positioned within the mold before the powder is poured therein. A portion of the steel shank 24 is within the powder mixture 22 and another portion of the steel shank 24 is outside of the mixture 22. Shank 24 has threads 25 at one end thereof, and grooves 25A at the other end thereof.
Referring to the contents of the mold, there are a plurality of discrete diamonds 20 positioned at selected positions within the mold so as to be at selected positions on the surface of the finished product. The matrix powder 22 is a carbide-based powder which is poured into the mold 10 so as to be on top of the diamonds 20. The composition of the matrix powder 22 will be set forth hereinafter.
Once the diamonds 20 have been set and the matrix powder 22 poured into the mold, infiltrant alloy 26 is positioned on top of the powder mixture 22 in the mold 10. Then the top 16 is positioned over the mold, and the mold is placed into a furnace and heated to approximately 2200° F. so that the infiltrant 26 melts and infiltrates the powder mass. The result is an end product wherein the infiltrant bonds the powder together, the matrix holds the diamonds therein, and the composite is bonded to the steel shank.
Referring to
A steel shank 42 is positioned within the mold before the powder mixture is poured therein. A portion of the steel shank 42 is within the powder mixture 40 and another portion of the steel shank 42 is outside of the mixture. The shank 42 has grooves 43 at the end that is within the powder mixture.
Referring to the contents of the mold 30, there are a plurality of carbon blanks 38 positioned at selected positions within the mold so as to be at selected positions on the surface of the finished product. The matrix powder 40 is a carbide-based powder which is poured into the mold 30 so as to be on top of the carbon blanks 38. The composition of the matrix powder 40 will be set forth hereinafter.
Once the carbon blanks 38 have been set and the matrix powder 40 poured into the mold 30, infiltrant alloy 44 is positioned on top of the powder mixture in the mold. Then the top 36 is positioned over the mold, and the mold is placed into a furnace and heated to approximately 2200° F. so that the infiltrant melts and infiltrates the powder mass. The result is an intermediate product wherein the infiltrant bonds the powder together, also bonding the powder mass to the steel shank, and the carbon blanks define recesses in the surface of the infiltrated mass.
The carbon blanks are removed from bonded mass and a diamond composite insert, having a shape like that of the carbon blank, is brazed into the recess to form the end product. Typically, the diamond composite drill head has a layer of discrete diamonds along the side.
Referring to
The following tests were conducted to determine the performance of the inventive compositions as compared to a prior art composition, and in particular, to Prior Art Composition A. In all of the examples set forth below, the mesh size of the components of the metal matrix powder was determined according to ASTM Standard E-11-04, Standard Specification for Wire Cloth and Sieves for Testing Purposes.
For all of the specific examples, the infiltrant that was used to form the metal matrix was MACROFIL 53. The nominal composition of the MACROFIL 53 was 53.0 weight percent copper, 24.0 weight percent manganese, 15.0 weight percent nickel, and 8.0 weight percent zinc. The working temperature was equal to 1177 degrees Centigrade. The solidus temperature was equal to 952 degrees Centigrade, and the liquidus temperature was equal to 1061 degrees Centigrade. This infiltrant is sold by Belmont Metals Inc., 330 Belmont Avenue, Brooklyn, N.Y. 11207, under the name designation “VIRGIN binder 4537D” in 1 inch by ½ inch by ½ inch chunks. This alloy is identified as MACROFIL 53 by applicants' assignee (Kennametal Inc. of Latrobe, Pa. 15650), and this designation will be used in this application. Another suitable infiltrant is MACROFIL 65, which has the following nominal composition: 65 weight percent copper, 15 weight percent nickel, and 20 weight percent zinc. The working temperature was equal to 1177 degrees Centigrade. The solidus temperature was equal to 1040 degrees Centigrade, and the liquidus temperature was equal to 1075 degrees Centigrade. The MACROFIL 65 infiltrant is available through commercial sources that are easily accessible to one skilled in the art.
To form the metal matrix used in the examples herein, the powder mixture was placed in a mold along with MACROFIL 53 infiltrant, and heated at about 2200° F. until the infiltrant had adequately infiltrated the powder mass so as to bond it together. The mass was then allowed to cool. This mass was the body that was tested for abrasion resistance and for strength.
In order to evaluate the properties of the specific metal matrices of the specific examples, applicants performed testing of these specific examples to ascertain the wear resistance properties and the strength properties. The test results presented herein are in the form of a wear resistance index and a strength index. In order to develop these indices, the wear resistance and the strength of the Prior Art Composition A (see Table A below) were ascertained and this value was defined as 100 percent. The wear resistance and the strength of each one the metal matrices of Inventive Examples Nos. 1-11 was measured and then reported herein as a percentage of the wear resistance and strength, respectively, of Prior Art Composition A.
In reference to the testing for wear resistance, two tests were performed to arrive at the wear resistance index. The first test was designed to be along the lines of the Riley-Stoker method (ASTM B611 Standard) and the second test was a slurry erosion test similar to ASTM G76-05 Standard, but using water instead of gas. The test specimens were coins of the metal matrix to be subjected to the test. The test results for the Riley-Stoker method and the test results of the G76-05 slurry erosion test were averaged to arrive at the wear resistance index. The wear resistance testing was the same for the prior art, as well as the inventive examples.
In reference to the testing for the strength, two tests were performed to arrive at the strength index. The first test was designed to be along the general lines of a notched charpy impact test wherein the testing was done along the general lines of ASTM E23-05 or ASTM A370-05 Standard, and the second test was along the ASTM B406-76 Standard to ascertain transverse rupture strength. The test results for the charpy impact test and the test results for the transverse rupture strength test were averaged to arrive at the strength index. The strength testing was the same for the prior art, as well as for the inventive examples.
The prior art commercial matrix powder was designated as Prior Art Composition A. Table A sets forth the composition of the Prior Art Composition A powder.
Tables 1 through 11 set out the test results for inventive Examples 1 through 11. Each table presents the components, the particle size ranges for each component, and the content in weight percent for each component.
The composition including the particle size distribution of Example No. 1 is set forth below in Table 1. The abrasion resistance test results showed that the abrasion resistance of Example No. 1 was 122 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 1 was 100 percent of the strength of the Prior Art Composition A material. As can be seen from a comparison of the Prior Art Composition A material and Example No. 1, the microcrystalline tungsten carbide in the −325 Mesh particle size distribution was replaced with −325 Mesh sintered cobalt (6 weight percent) cemented tungsten carbides. It should be F appreciated that even though the above specific substitution used a sintered cobalt cemented tungsten carbide particles that contained 6 weight percent cobalt, applicants contemplate that the sintered cobalt cemented tungsten carbide particles may contain between about 4 weight percent and about 10 weight percent cobalt.
The composition including the particle size distribution of Example No. 2 is set forth below in Table 2. The abrasion resistance test results showed that the abrasion resistance of Example No. 2 was 118 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 2 was 104 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 2, the macrocrystalline tungsten carbide in the −230+325 Mesh particle size distribution was replaced with −230+325 Mesh sintered cobalt cemented tungsten carbide (6 weight percent) particles.
The composition including the particle size distribution of Example No. 3 is set forth below in Table 3. The abrasion resistance test results showed that the abrasion resistance of Example No. 3 was 116 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 3 was 108 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 3, the macrocrystalline tungsten carbide in the −170+230 Mesh particle size distribution was replaced with −170+230 Mesh sintered cobalt cemented tungsten carbide (6 weight percent) particles.
The composition including the particle size distribution of Example No. 4 is set forth below in Table 4. The abrasion resistance test results showed that the abrasion resistance of Example No. 4 was 121 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 4 was 114 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 4, the macrocrystalline tungsten carbide in the −120+170 Mesh particle size distribution was replaced with −120+170 Mesh sintered cobalt cemented tungsten carbide (6 weight percent) particles.
The composition including the particle size distribution of Example No. 5 is set forth below in Table 5. The abrasion resistance test results showed that the abrasion resistance of Example No. 5 was 122 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 5 was 124 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 5, the macrocrystalline tungsten carbide in the −80+120 Mesh particle size distribution was replaced with −80+120 Mesh sintered cobalt cemented tungsten carbide (6 weight percent) particles.
The composition including the particle size distribution of Example No. 6 is set forth below in Table 6. The abrasion resistance test results showed that the abrasion resistance of Example No. 6 was 134 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 6 was 113 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 6, the macrocrystalline tungsten carbide in the −80+120 Mesh particle size distribution and in the −325 Mesh particle size distribution were replaced with sintered cobalt cemented tungsten carbide (6 weight percent) particles in the same particle size distributions.
The composition including the particle size distribution of Example No. 7 is set forth below in Table 7. The abrasion resistance test results showed that the abrasion resistance of Example No. 7 was 141 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 7 was 117 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 7, the macrocrystalline tungsten carbide in the −80+120 Mesh particle size distribution and the −230+325 Mesh particle size distribution were replaced with sintered cobalt cemented tungsten carbide (6 weight percent) particles in the same particle size distributions.
The composition including the particle size distribution of Example No. 8 is set forth below in Table 8. The abrasion resistance test results showed that the abrasion resistance of Example No. 8 was 135 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 8 was 118 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 8, the macrocrystalline tungsten carbide in the −80+120 Mesh particle size distribution and the −170+230 Mesh particle size distribution were replaced with sintered cobalt cemented tungsten carbide (6 weight percent) particles in the same particle size distributions.
The composition including the particle size distribution of Example No. 9 is set forth below in Table 9. The abrasion resistance test results showed that the abrasion resistance of Example No. 9 was 140 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 9 was 128 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 9, the macrocrystalline tungsten carbide in the −80+120 Mesh particle size distribution and the −120+170 Mesh particle size distribution were replaced with sintered cobalt cemented tungsten carbide (6 weight percent) particles in the same particle size distributions.
The composition including the particle size distribution of Example No. 10 is set forth below in Table 10. The abrasion resistance test results showed that the abrasion resistance of Example No. 10 was 144 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 10 was 123 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 10, the macrocrystalline tungsten carbide in the −80+120 Mesh particle size distribution and in the −120+170 Mesh particle size distribution were replaced with crushed sintered cobalt (6 weight percent cobalt) tungsten carbide particles in the −80+170 Mesh particle size distributions.
The composition including the particle size distribution of Example No. 11 is set forth below in Table 11. The abrasion resistance test results showed that the abrasion resistance of Example No. 11 was 144 percent of the abrasion resistance of the Prior Art Composition A material. The strength test results showed that the strength of Example No. 11 was 112 percent of the strength of the Prior Art Composition A material.
As can be seen from a comparison of the Prior Art Composition A material and Example No. 11, the macrocrystalline tungsten carbide in the −170+325 Mesh particle size distribution (i.e., the combination of the −170+230 Mesh and the −230+326 Mesh and the −325 Mesh particle size distributions) was replaced with −170+325 Mesh crushed sintered cobalt (6 weight percent cobalt) tungsten carbide particles.
In looking at the overall results, it becomes apparent that the materials of the present invention provide increases in both abrasion resistance and strength as compared to the commercial Prior Art Composition A material. A more detailed discussion of these advantages now follows.
It can be seen that because of the substitution of crushed cemented tungsten carbides in the composition, both the wear resistance and the strength of the material experienced an increase as compared to the Prior Art Composition A material. In some cases, only one macrocrystalline tungsten carbide component was replaced with the crushed cemented (cobalt) tungsten carbide. In other cases, more than one macrocrystalline tungsten carbide component was replaced or substituted with the crushed cemented (cobalt) tungsten carbide particles.
Table 12 below compares the results of those compositions in which only one macrocrystalline tungsten carbide component was substituted with crushed cemented (cobalt) tungsten carbide particles. In Table 12, the substitution/weight percent refers to the particle size range (and how much) of the macrocrystalline tungsten carbide particles that was replaced with the crushed cemented (cobalt) tungsten carbide particles. The abrasion resistance is reported in an increase relative to the abrasion resistance of the Prior Art Composition A, and the strength is reported in an increase relative to the strength of the Prior Art Composition A material. More specifically, the abrasion resistance number was determined by performing a Riley-Stoker test and a slurry erosion test, which were normalized relative to the Prior Art Composition A and the normalized numbers averaged. The strength was determined by performing a transverse rupture strength test and an impact toughness test, which were normalized relative to the Prior Art Composition A and the normalized numbers averaged.
It becomes apparent from looking at Examples 1 and 2, that even when the smaller sized macrocrystalline tungsten carbide components are replaced by crushed cemented (cobalt) tungsten carbide particles, there is an increase (i.e., 118-122%) in the abrasion resistance as compared to the Prior Art Composition A material and an increase (up to 104%) in the strength as compared to the Prior Art Composition A material. It is also apparent from looking at the test results for Examples 3 through 5, that substitutions in the medium to larger sizes of particle size ranges provides for significant increases in both the abrasion resistance and strength (e.g., impact toughness). For Examples 3 through 5, the abrasion resistance ranges between 116% and 122% of the abrasion resistance of the Prior Art Composition A material, and the strength ranges between 108% to 124% of the strength of the Prior Art Composition A material.
It should also be noted that there is a general trend that as the particle size for the substituted particle size ranges increases so does the abrasion resistance and the strength. For example, in Example 1, which is a substitution in the −325 Mesh particle size range, the abrasion resistance is equal to 122% of the abrasion resistance of the Prior Art Composition A material and the strength is equal to 100% of the strength of the Prior Art Composition A material. In Example 5, which is a substitution in the −80+120 Mesh particle size range, the abrasion resistance is equal to 122% of the abrasion resistance of the Prior Art Composition A material and the strength is equal to 124% of the strength of the Prior Art Composition A material.
While the results that were obtained with the substitution of a single macrocrystalline tungsten carbide component with crushed cemented (cobalt) tungsten carbide particles were beneficial, applicant found that multiple substitutions, i.e., substitution of multiple particle size ranges of macrocrystalline tungsten carbide with crushed cemented (cobalt) tungsten carbide particles, produced greater benefits, i.e., a larger increase in properties. Table 13 is set forth below.
Table 13 presents a comparison of the results for the examples in which there were two substitutions. Like for Table 12, in Table 13 the substitution/weight percent refers to the particle size range (and how much) of the macrocrystalline tungsten carbide particles that was replaced with the crushed cemented (cobalt) tungsten carbide particles. The abrasion resistance is reported in an increase relative to the abrasion resistance of the Prior Art Composition A, and the strength is reported in an increase relative to the strength of the Prior Art Composition A material.
A review of the test results for Examples 6 through 9 shows that multiple substitutions (in these cases two substitutions) result in an increase in the abrasion resistance relative to the abrasion resistance of the Prior Art Composition A material. The multiple substitutions also result in an increase in the strength as compared to the strength of the Prior Art Composition A material. The largest combined increase in abrasion resistance and strength occurred in Example 9 in which the substitution occurred in adjacent particle size ranges (i.e., −170+230 Mesh and −120+170 Mesh) that were larger particle size ranges. For the material of Example 9, the abrasion resistance was 140% of the abrasion resistance of the Prior Art Composition A material, and the strength was 128% of the strength of the Prior Art Composition A material.
With respect to the substitution of macrocrystalline tungsten carbide by crushed cemented (cobalt) tungsten carbide particles, even single substitution in the smaller particle size ranges resulted in an improvement of the abrasion resistance, but not as much improvement in the strength. The material experienced a greater improvement in the combined properties of abrasion resistance and strength as the substituted particle sizes increased in size. For example, Example 5 had the largest particle size distribution (−80+120 Mesh) and exhibited the greatest overall increase in the combined properties (i.e., a 122% increase in abrasion resistance and a 124% increase in strength).
The substitution of multiple (in this case two) particle size ranges resulted in even better overall improvement due to increases in abrasion resistance and consistent increases in strength. Along the same general line as the single substitution results, it appears that substitutions in the larger particle size ranges resulted in better results. In this regard, Example 9, which had the largest particle size range substitutions, experienced the best overall results with an abrasion resistance equal to 140% of the abrasion resistance of the Prior Art Composition A material and a strength equal to 128% of the strength of the Prior Art Composition A material.
The same trend associated with the multiple substitution of the macrocrystalline tungsten carbide particles with the crushed cemented (cobalt) tungsten carbide particles also existed for a different crushed cemented (cobalt) tungsten carbide particles (crushed sintered cobalt (6 weight percent cobalt) tungsten carbide particles). More specifically, in Example 10 crushed cemented (cobalt) tungsten carbide particles (crushed sintered cobalt (6 weight percent cobalt) tungsten carbide particles) replaced the macrocrystalline tungsten carbide in the −80+120 Mesh particle size range (15 weight percent) and in the −210+170 Mesh particle size range (15 weight percent). The test results were along the lines of Example 9 in that the abrasion resistance was equal to 144% of the abrasion resistance of the Prior Art Composition A material and the strength was equal to 123% of the strength of the Prior Art Composition A material.
Example 11 comprised a triple substitution in which macrocrystalline tungsten carbide particles in the following size ranges were replaced with crushed cemented (cobalt) tungsten carbide particles (crushed sintered cobalt (6 weight percent cobalt) tungsten carbide particles): −170+230 Mesh (15 weight percent) and −230+325 Mesh (15 weight percent) and −325 Mesh (15 weight percent). In Example 11, the abrasion resistance was equal to 144% of the abrasion resistance of the Prior Art Composition A material and the strength was equal to 112% of the strength of the Prior Art Composition A material. These substitutions occurred in the smaller to medium sizes of particle size ranges (e.g., −170+230 Mesh and −230+325 Mesh) as compared to larger particle size ranges (e.g., −80+120 Mesh or −120+170 Mesh). The results of Example 11 appear to be consistent with the overall results that occur when the substitutions include the larger sized particle size range.
It should be appreciated that the crushed cemented tungsten carbide particles may include a binder other than or in addition to cobalt. In this regard, the binder could be any one or more of cobalt or nickel.
It is apparent that applicant has invented a new and useful infiltrant matrix powder that exhibits an improvement in abrasion resistance and strength as compared to a commercially available infiltrant matrix powder. These improvements in abrasion resistance and strength provide for improved performance when used in various applications.
All patents, patent applications, articles and other documents identified herein are hereby incorporated by reference herein. Other embodiments of the invention may be apparent to those skilled in the art from a consideration of the specification or the practice of the invention disclosed herein. It is intended that the specification and any examples set forth herein be considered as illustrative only, with the true spirit and scope of the invention being indicated by the following claims.
