FIELD OF THE INVENTION
The present invention is directed to mineral grinding articles. More particularly, the present invention is directed to mineral grinding articles having a plurality of particles dispersed in a material having reduced hardness compared to the plurality of particles.
BACKGROUND OF THE INVENTION
Coal crusher rolls are used to crush coal which is fed to a boiler for producing steam, reducing the size of the coal units from about 20 mm to about 200 mesh size. During the crushing process, the grinding surfaces of the coal crusher rolls become worn due to the inherent abrasive nature of the coal which is being crushed. Coals which have elevated ash content are typically more abrasive than coals with lower ash content, and may cause faster erosion of the grinding surfaces of the coal crusher roles, both by attrition and wear from the crushing loads applied on the coal crusher rolls. Further degradation of the coal crusher rolls may be caused by contaminants in the coal supply such as iron and stone, which may cause sudden impacts when introduced into the coal crusher.
Coal crusher rolls may be encased in sinter-cast materials to extend the useful life, but such solutions are expensive and are limited in the increase in useful life they provide.
BRIEF DESCRIPTION OF THE INVENTION
In an exemplary embodiment, a mineral grinding article includes a support portion having a support portion hardness, and a grinding portion disposed on the support portion, wherein the grinding portion includes a grinding surface. The grinding portion further includes a plurality of segmented wear strip, and the

plurality of segmented wear strips includes a matrix having a matrix hardness and a plurality of particles having a particle hardness dispersed in the matrix. The particle hardness is greater than the matrix hardness and is greater than the support portion hardness.
In another exemplary embodiment, a mineral grinding article includes a cast portion having a cast portion hardness and a grinding surface, and a plurality of particles having a particle hardness dispersed in the cast portion. The cast portion includes a material selected from the group consisting of chrome-iron alloy including, by weight, at least about 30% chrome, cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel, cast steel, locomotive wheel steel, or combinations thereof. The particle hardness is greater than the cast portion hardness.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an assembly, according to an embodiment of the present disclosure.
FIG. 2 is an expanded perspective view of the mineral grinding article of FIG. 1, according to an embodiment of the present disclosure.
FIG. 3 is a sectional view along lines 3-3 of the mineral grinding article of FIG. 1, according to an embodiment of the present disclosure.

FIG. 4 is a sectional view along lines 4-4 of the mineral grinding article of FIG. 2, according to an embodiment of the present disclosure.
FIG. 5 is a sectional view along lines 5-5 of the mineral grinding article of FIG. 1, according to an embodiment of the present disclosure.
Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.
DETAILED DESCRIPTION
Provided are exemplary mineral grinding articles, and methods for forming the mineral grinding articles. Embodiments of the present disclosure, in comparison to articles and methods not utilizing one or more features disclosed herein, decrease costs, increase process efficiency, increase durability, increase reliability, increase service lifetime, decrease erosion, decrease wear, or a combination thereof.
Referring to FIGS. 1-4, in one embodiment, a mineral grinding article 100 includes a support portion 300 having a support portion hardness, and a grinding portion 302 disposed on the support portion 300, wherein the grinding portion 302 includes a grinding surface 306. The grinding portion 302 further includes a plurality of segmented wear strips 200, and the plurality of segmented wear strips 200 includes a matrix 400 having a matrix hardness and a plurality of particles 402 having a particle hardness dispersed in the matrix 400. The particle hardness is greater than the matrix hardness and is greater than the support portion hardness.
The support portion hardness is an average hardness of the support portion 300 determined at a support portion surface 304 proximal to the grinding portion 302. The matrix hardness may be less than the support hardness, about equal to the

support hardness, or greater than the support portion hardness, and the particle hardness is greater than the matrix hardness and the support hardness. The grinding surface 306 is distal across the grinding portion 302 from the support portion surface 304.
The support potion surface 304 may include any suitable material structure, including, but not limited to, a weld hardfaced structure, a weld overlaid structure, a cold sprayed structure, a laser cladded structure, a coated structure, a cast structure, a composite structure, or combinations thereof.
The support portion 300 may include any suitable material, including, but not limited to, a chrome-iron alloy including, by weight, at least about 30% chrome, cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel (MANGALLOY®), cast steel, locomotive wheel steel, the composition of the matrix 400, or combinations thereof. In one embodiment, the support portion 300 includes the plurality of particles 402. The plurality of particles 402 may be randomly dispersed in the support portion, multi-modally dispersed in the support portion 300, essentially uniformly dispersed in the support portion, uniformly dispersed in the support portion 300, dispersed in the support portion per a predetermined pattern, or combinations thereof. As used herein, "multi-modally dispersed" indicates a region having a greater concentration and a region having a lesser concentration, and "essentially uniformly dispersed" indicates a variance in concentration of less than about 20%, alternatively, less than about 15%, alternatively less than about 10%, alternatively less than about 5%, alternatively less than about 1%. "Multi-modally dispersed" further may refer to the distribution of different sizes within the plurality of particles 402.
The at least one grinding portion 302 may be disposed directly on the support portion surface 304 or may be disposed on an intermediate layer (not shown). The

support portion 300 may include any suitable structural composition. The support portion 300 may be hollow (FIG. 2) or may be solid throughout (FIG. 3.) In one embodiment (FIG. 3), the support portion 300 includes a first layer 308 having a first layer hardness, and a second layer 310 having a second layer hardness. The second layer hardness may be greater than the first layer hardness or lesser than the first layer hardness. The support portion 300 may further include any suitable number of additional layers. In one embodiment, the support portion 300 includes a first layer 308 and a second layer 310, the second layer 310 being disposed between the first layer 308 and the grinding portion 302, wherein the second layer hardness is greater than the first layer hardness and the second layer hardness is less than, greater than, or about equal to the matrix hardness.
The first layer 308 may include any suitable material, including, but not limited to, cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel (MANGALLOY®), cast steel, locomotive wheel steel, or combinations thereof. The first layer 308 may include any suitable diameter, including, but not limited to, a first layer average diameter 312 of between about 10 mm and about 3 m, alternatively between about 25 mm and about 2.5 m, alternatively between about 50 mm and about 2 m.
The second layer 310 may include any suitable material, including, but not limited to, a chrome-iron alloy including, by weight, at least about 30% chrome, cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel (MANGALLOY®), cast steel, locomotive wheel steel, or combinations thereof. The second layer 310 may include any suitable thickness, including, but not limited to, a second layer thickness 314 of between about 0.1 mm and about 50 mm, alternatively between about 0.1 mm and about 10 mm, alternatively between

about 0.25 mm and about 5 mm, alternatively between about 0.5 mm and about 3 mm.
The mineral grinding article 100 may be any suitable article. In one embodiment, the mineral grinding article 100 is a grinding roll 102. The grinding roll 102 may be an independent component or the grinding roll 102 may be a component of a grinding apparatus 104, such as, but not limited to, a bowl mill, a ball and race mill, a drum and ball mill, a coal crusher, or combinations thereof. In one embodiment, the grinding apparatus 104 is a coal grinding apparatus, and the grinding roll 102 is a coal grinding roll.
The plurality of particles 402 may include any suitable particles. In one embodiment, the plurality of particles 402 includes a plurality of ceramic particles. Suitable ceramic particles may include, but are not limited to, particles formed from a material including metal carbides, metal borides, metal oxides, boron nitrides, boron carbides, boron carbon nitrides, zirconia toughened aluminas, silicon carbides, silicon nitrides, silicon oxy-nitrides, silicon aluminum oxy-nitrides, sintered derivatives thereof, or combinations thereof. In one embodiment, wherein the support portion includes the plurality of particles 402, the plurality of particles 402 includes a first composition in the plurality of segmented wear strips 200 and a second composition in the support portion 300, and the first composition is distinct from the second composition or the first composition is substantially identical to the second composition.
The plurality of particles 402 may include any suitable particle size distribution, including, but not limited to, a particle size distribution of up to about 10 nm, alternatively up to about 20 nm, alternatively up to about 25 nm, alternatively up to about 10 mm, alternatively up to about 20 mm, alternatively up to about 25 mm, alternatively from about 1 nm to about 25 mm, alternatively from about 1 nm to about 25 nm, alternatively from about 1 mm to about 25 mm. In one

embodiment, the plurality of particles 402 includes a plurality of fine particles having a fine particle size distribution up to about 25 nm, and a plurality of coarse particles having a coarse particle size distribution from about 1 mm to about 25 mm, the plurality of fine particles and the plurality of coarse particles being intermixed. The plurality of fine particles and the plurality of coarse particles may be intermixed within the plurality of particles 402 and be distributed to optimize protection against erodent abrasive particles having different sizes. The plurality of fine particles in the plurality of particles 402 may also fill in gaps which may be present between the plurality of coarse particles in the plurality of particles 402, thereby enhancing the resistance of the plurality of particles 402 to erosion and abrasion.
In one embodiment, the plurality of particles 402 in the mineral grinding article 100 is essentially free of oxidation and decarburization chemical structure modifications. As used herein, "essentially free" indicates that less than about 20%, by weight, of the plurality of particles 402 are oxidized or decarburized, alternatively less than about 15%, by weight, alternatively less than about 10%, by weight, alternatively less than about 5%, by weight, alternatively less than about P/o, by weight, alternatively less than about 0.5%, by weight.
The matrix 400 may include any suitable material, including, but not limited to, cobalt-chromium alloys, nickel-chromium alloys, nickel aluminum alloys, iron-chromium alloys, iron-chromium-aluminum alloys, nickel-aluminum-chromium alloys, nickel-chromium-boron-silicon alloys, cobalt-chromium-boron-silicon alloys, iron-chromium-boron-silicon alloys, Hadfield steels, or combinations thereof.
The plurality of particles 402 may be randomly dispersed in the matrix 400, multi-modally dispersed in the matrix 400, essentially uniformly dispersed in the matrix 400, uniformly dispersed in the matrix 400, dispersed in the matrix 400 per

a predetermined pattern, or combinations thereof. Under operating conditions, the predetermined pattern at the grinding surface 306 may result in a three-dimensional pattern formed by the differential abrasion of the plurality of particles 402 and the matrix 400, which may be designed to provide additional operational enhancements. The predetermined pattern may be any suitable pattern, including, but not limited to, a hexagonal "honey-comb" lattice, a pentagonal lattice, a quadrilateral lattice, a triangular lattice, a striped pattern, a zig-zag pattern, or combinations thereof, which may form, respectively, after operational wear, a honey-comb texture, a pentagonal texture, a cuboid texture, a pyramidal texture, a ridged texture, a zig-zag ridged texture, or combinations thereof. In another embodiment, a higher concentration of the plurality of particles is disposed in regions of the plurality of segmented wear strips 200 where the mineral grinding article 100 is subjected to greater wear during operation, such as, by way of example, the middle of the mineral grinding article 100 relative to the edges of the mineral grinding article 100.
The plurality of segmented wear strips 200 may be secured to the support portion 300 by any suitable joining configuration, including, but not limited to, mechanical attachment to the support portion 300, welding to the support portion 300, forming a weld 410 joining the plurality of segmented wear strips 200 to the support portion 300, brazing to the support portion 300, forming a braze layer 412 joining the plurality of segmented wear strips 200 to the support portion 300, or combinations thereof. The support portion 300 may include a lip 206 above, below, or both above and below (shown) the plurality of segmented wear strips 200, or the plurality of segmented wear strips 200 may span the grinding surface 306 (not shown). The plurality of segmented wear strips 200 may be adjacent to one another and contacting one another (shown), or may include spacing interspersed between the plurality of segmented wear strips 200 (not shown).

Mechanical attachment may include, but is not limited to, fastening with a fastener 202, such as bolts (shown) or rivets, by fitted joints, or combinations thereof. In one embodiment (FIGS. 2 and 4), the fastener 200 attaches the plurality of segmented wear strips 200 to the support portion 300 from an interior face 204 of the mineral grinding article 100, wherein the fastener 200 does not penetrate the entire strip thickness 404. Fitted joints may include, but are not limited to, bridle joints, finger joints, dovetail joints, dado joints, groove joints, tongue and groove joints, mortise and tenon joints, splice joints, half lap spice joints, bevel lap splice joints, tabled splice joints, and tapered finder splice joints, or combinations thereof.
Welding and brazing may include any suitable welding or brazing technique, including, but not limited to, brazing with braze filler, brazing with braze foil, brazing with braze tape, brazing with pre-sintered preforms, spot welding, resistance spot welding, resistance seam welding, projection welding, flash welding, upset welding, arc welding, shielded metal arc welding, gas tungsten arc welding, gas metal arc welding, submerged arc welding, plasma arc welding, flux cored arc welding, bare metal arc welding, electroslag welding, laser welding, electron beam welding, ultrasonic welding, friction welding, stir friction welding, gas welding, oxyacetylene welding, oxygen/propane welding, oxyhydrogen welding, pressure gas welding, resistance welding, hot isostatic pressure welding, induction welding, laser-hybrid welding, hybrid welding, tribrid welding, electrogas welding, or combinations thereof.
The plurality of segmented wear strips 200 may be removably attached to the support portion 300 or permanently attached to the support portion 300. As used herein, "removably attached" indicates that the plurality of segmented wear strips 200 are removable without damaging the support portion 300, and "permanently attached" indicates that removal of the plurality of segmented wear strips 200

would damage the support potion 300.
The plurality of segmented wear strips 200 may include a strip thickness 404 of up to about 100 mm, alternatively between about 0.25 mm and about 100 mm, alternatively between about 0.5 mm and about 75 mm, alternatively between about 1 mm and about 50 mm, alternatively between about 0. 25 mm and about 20 mm, alternatively between about 10 mm and about 50 mm, alternatively between about 45 mm and about 75 mm, alternatively between about 85 mm and about 100 mm. In one embodiment, wherein the mineral grinding article 100 includes a round conformation, the plurality of segmented wear strips 200 includes a strip width 406 of up to about 25% of a diameter of the mineral grinding article 100. In another embodiment, the plurality of segmented wear strips 200 includes a strip height 408 of at least about 80% of the grinding surface 306 of the mineral grinding article 100.
In one embodiment, the plurality of particles 402 is dispersed in the matrix 400 at a density (average, by weight) of at least about 50%, alternatively at least about 55%), alternatively at least about 60%>, alternatively at least about 65%, alternatively at least about 75%, alternatively at least about 80%, alternatively at least about 85%, alternatively at least about 90%, alternatively between about 50%) to about 99%), alternatively between about 60% to about 95%, alternatively between about 75% to about 94%, alternatively between about 85% to about 93%, alternatively between about 90% to about 95%, alternatively about 93%.
Referring to FIGS. 1 and 5, in one embodiment, a mineral grinding article 100 includes a cast portion 500 having a cast portion hardness and a grinding surface 306, and a plurality of particles 402 having a particle hardness dispersed in the cast portion 500. The particle hardness is greater than the cast portion hardness. The cast portion 500 may include any suitable material, including, but not limited to, a chrome-iron alloy including, by weight, at least about 30% chrome, cast iron,

spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel (MANGALLOY®), cast steel, locomotive wheel steel, or combinations thereof. In one embodiment, the plurality of particles 402 includes a plurality of ceramic particles. Suitable ceramic particles may include, but are not limited to, particles formed from a material including metal carbides, metal borides, metal oxides, boron nitrides, boron carbides, boron carbon nitrides, zirconia toughened aluminas, silicon carbides, silicon nitrides, silicon oxy-nitrides, silicon aluminum oxy-nitrides, sintered derivatives thereof, or combinations thereof.
The plurality of particles 402 may be randomly dispersed in the cast portion 500, multi-modally dispersed in the cast portion 500, essentially uniformly dispersed in the cast portion 500, uniformly dispersed in the cast portion 500, dispersed in the cast portion 500 per a predetermined pattern, or combinations thereof. Under operating conditions, the predetermined pattern at the grinding surface 306 may result in a three-dimensional pattern formed by the differential abrasion of the plurality of particles 402 and the cast portion 500, which may be designed to provide additional operational enhancements. The predetermined pattern may be any suitable pattern, including, but not limited to, a hexagonal "honey-comb" lattice, a pentagonal lattice, a quadrilateral lattice, a triangular lattice, a striped pattern, a zig-zag pattern, or combinations thereof, which may form, respectively, after operational wear, a honey-comb texture, a pentagonal texture, a cuboid texture, a pyramidal texture, a ridged texture, a zig-zag ridged texture, or combinations thereof. In another embodiment, a higher concentration of the plurality of particles is disposed in regions of the cast portion 500 where the mineral grinding article 100 is subjected to greater wear during operation, such as, by way of example, the middle of the mineral grinding article 100 relative to the edges of the mineral grinding article 100.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

WE CLAIM
1. A mineral grinding article, comprising:
a support portion having a support portion hardness; and
a grinding portion disposed on the support portion, the grinding
portion including a plurality of segmented wear strips, the plurality of
segmented wear strips including:
a matrix having a matrix hardness; and
a plurality of particles having a particle hardness dispersed in the
matrix, the particle hardness being greater than the matrix
hardness and greater than the support portion hardness,
wherein the grinding portion further includes a grinding surface.
2. The mineral grinding article as claimed in claim 1, wherein the support portion includes the plurality of particles.
3. The mineral grinding article as claimed in claim 2, wherein the plurality of particles includes a first composition in the plurality of segmented wear strips and a second composition in the support portion, and the first composition is distinct from the second composition.
4. The mineral grinding article as claimed in claim 2, wherein the plurality of particles includes a first composition in the plurality of segmented wear strips and a second composition in the support portion, and the first composition is substantially identical to the second composition.
5. The mineral grinding article as claimed in claim 1, wherein the plurality of segmented wear strips is mechanically attached to the support portion.
6. The mineral grinding article of claim 5, wherein the plurality of segmented wear strips is attached to the support portion from an interior face of the mineral grinding article.

7. The mineral grinding article as claimed in claim 1, wherein the plurality of segmented wear strips is welded to the support portion.
8. The mineral grinding article as claimed in claim 1, wherein the plurality of segmented wear strips is removably attached to the support portion.
9. The mineral grinding article as claimed in claim 1, wherein the support portion includes:
a first layer having a first layer hardness; and
a second layer having a second layer hardness greater than the first
layer hardness;
wherein the second layer is disposed between the first layer and the at
least one grinding portion.
10. The mineral grinding article as claimed in claim 9, wherein the first layer includes a material selected from the group consisting of cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel, cast steel, locomotive wheel steel, and combinations thereof.
11. The mineral grinding article as claimed in claim 9, wherein the second layer includes a material selected from the group consisting of chrome-iron alloy including, by weight, at least about 30% chrome, cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel, cast steel, locomotive wheel steel, the matrix, and combinations thereof.
12. The mineral grinding article as claimed in claim 1, wherein a support portion surface includes a material structure selected from the group consisting of weld hardfaced, weld overlaid, cold sprayed, laser cladded, coated, cast, composite, and combinations thereof.

13. The mineral grinding article as claimed in claim 1, wherein the plurality of segmented wear strips includes a strip thickness of up to about 100 mm.
14. The mineral grinding article as claimed in claim 1, wherein the mineral grinding article is a coal grinding roll.
15. The mineral grinding article as claimed in claim 1, wherein the plurality of particles includes a plurality of ceramic particles, the plurality of ceramic particles being selected from the group consisting of metal carbides, metal borides, metal oxides, boron nitrides, boron carbides, boron carbon nitrides, zirconia toughened aluminas, silicon carbides, silicon nitrides, silicon oxy-nitrides, silicon aluminum oxy-nitrides, sintered derivatives thereof, and combinations thereof.
16. The mineral grinding article as claimed in claim 1, wherein the matrix includes a material selected from the group consisting of cobalt-chromium alloys, nickel-chromium alloys, nickel aluminum alloys, iron-chromium alloys, iron-chromium-aluminum alloys, nickel-aluminum-chromium alloys, nickel-chromium-boron-silicon alloys, cobalt-chromium-boron-silicon alloys, iron-chromium-boron-silicon alloys, Hadfield steels, and combinations thereof.
17. The mineral grinding article as claimed in claim 1, wherein the plurality of particles is essentially uniformly dispersed in the matrix.
18. The mineral grinding article as claimed in claim 1, wherein the plurality of particles is dispersed non-uniformly in the matrix, according to a predetermined pattern.
19. The mineral grinding article as claimed in claim 1, wherein the plurality of particles includes a plurality of fine particles having a fine particle size distribution up to about 25 nm, and a plurality coarse of particles having a coarse particle size distribution from about 1 mm to about 25 mm, the plurality of fine particles and the plurality coarse of particles being intermixed.

20. A mineral grinding article, comprising:
a cast portion having a cast portion hardness, the cast portion including a material selected from the group consisting of chrome-iron alloy including, by weight, at least about 30% chrome, cast iron, spheroidal graphite iron, white cast iron, cast iron including niobium, cast iron including chromium, cast iron including titanium, Hadfield steel, cast steel, locomotive wheel steel, and combinations thereof; and a plurality of particles having a particle hardness dispersed in the cast portion, the particle hardness being greater than the cast portion hardness, wherein the cast portion further includes a grinding surface.