Abstract: Methods of forming bit bodies for earth-boring bits include assembling green components, brown components, or fully sintered components, and sintering the assembled components. Other methods include isostatically pressing a powder to form a green body substantially composed of a particle-matrix composite material, and sintering the green body to provide a bit body having a desired final density. Methods of forming earth-boring bits include providing a bit body substantially formed of a particle-matrix composite material and attaching a shank to the body. The body is provided by pressing a powder to form a green body and sintering the green body. Earth-boring bits include a unitary structure substantially formed of a particle-matrix composite material. The unitary structure includes a first region configured to carry cutters and a second region that includes a threaded pin. Earth-boring bits include a shank attached directly to a body substantially formed of a particle-matrix composite material.

Abstract: Earth-boring tools for drilling subterranean formations include a particle-matrix composite material comprising a plurality of at least partially carburized monotungsten carbide and ditungsten carbide eutectic particles dispersed throughout a matrix material. In some embodiments, the particles are at least substantially fully carburized monotungsten carbide and ditungsten carbide eutectic particles. In further embodiments, the particles are generally spherical or at least substantially spherical. Methods of forming such particles include exposing a plurality of monotungsten carbide and ditungsten carbide eutectic particles to a gas containing carbon. Methods of manufacturing such tools include providing a plurality of at least partially carburized monotungsten carbide and ditungsten carbide eutectic particles or at least substantially completely carburized monotungsten carbide and ditungsten carbide eutectic particles within a matrix material.

Abstract: A cemented carbide tool comprising hard constituents in a binder phase of Co and/or Ni and at least one surface portion and an interior portion in which surface portion the grain size is smaller than in the interior portion is disclosed. The surface portion with the fine grain size has a lower binder phase content than the interior portion. A method to form the cemented carbide cutting tool is also disclosed.

Abstract: A method for manufacturing functionally graded cemented tungsten carbide with hard and wear-resistant surface and tough core is described. The said functionally graded cemented tungsten carbide (WC—Co) has a surface layer having a reduced amount of cobalt. Such a hard surface and tough core structure is an example of functionally graded materials in which mechanical properties are optimized by the unique combination of wear-resistance and toughness. WC—Co with reduced-cobalt surface layer may be fabricated through a carburization heat treatment process following conventional liquid phase sintering. The graded WC—Co thus obtained contains no brittle ? phase.

Abstract: The present invention is a method for producing functionally graded materials that contain a hard phase that is embedded in a metal matrix phase. The material have a continuous gradient of a matrix metal phase. An example of these types of materials include functionally graded cemented tungsten carbide (the hard phase) that has a continuous gradient of cobalt (the matrix metal) from one reference position, for example, one surface of a part, to another reference position, for example, the opposite surface of the part or within the part. The functionally graded materials are sintered via a liquid phase sintering (LPS) technique. In order to achieve the desired continuous gradient of the matrix metal, an initial gradient of one of the chemical elements of the hard phase is designed and built into the part prior to liquid phase sintering.

Abstract: A cemented carbide cutting tool insert/button for mining and construction comprising hard constituents in a binder phase of Co and/or Ni and at least one surface portion and an interior portion in which surface portion the grain size is smaller than in the interior portion is disclosed. The surface portion with the smaller grain size has a lower binder phase content than the interior portion. A method to form the cemented carbide cutting tool insert/button is also disclosed.

Abstract: The present invention provides a method of gel-casting WC—Co cemented carbide powder, where the resulting gelled body can be of complex shape and has a high green density, a good homogeneity and sufficiently good mechanical properties for the gelled body to be demolded and dried without significant shape-distortions and cracking. The method relates to the forming of a gelled body through the gelling of an aqueous slurry of WC—Co cemented carbide powder with good dispersion characteristics, where the gelling is achieved by the temperature induced polymerization reaction between a monomer and a cross-linker, catalyzed by a free-radical initiator. By further subjecting the body to drying, heating, and sintering, a dense cemented carbide body is obtained.

Abstract: Polycrystalline diamond (PCD) carbide composites of this invention have a microstructure comprising a plurality of granules formed from PCD, polycrystalline cubic boron nitride, or mixture thereof, that are distributed within a substantially continuous second matrix region that substantially surrounds the granules and that is formed from a cermet material. In an example embodiment, the granules are polycrystalline diamond and the cermet material is cemented tungsten carbide. PCD carbide composites of this invention display improved properties of fracture toughness and chipping resistance, without substantially compromising wear resistance, when compared to conventional pure PCD materials.

Abstract: A threaded nozzle for use in a cutter bit is disclosed. Threads are either machined into or pressed into a pressed powder nozzle then the nozzle is sintered. Threads of the nozzles of the present invention exhibit improved hardness and have a rougher surface finish than threads machined post-sintering. Shaping of the threads into the nozzle before sintering is also more economical and efficient than post-sintering machining.

Abstract: Provided are a composite wear-resistant member which can be manufactured with a lowered sintering temperature, and thus can prevent the carbonization of a material around super hard particles such as diamond; and a method for manufacturing the member. The member, characterized in that it comprises hard particles comprising diamond particles and WC particles and an iron group metal containing phosphorus as a binding material, wherein the content of phosphorus is 0.01 to 2.0 wt % relative to the total weight of the WC particles and the binding material.

Abstract: A method of sintering a composite body characterized by a transition metal carbide phase (such as a ZrC phase) substantially evenly distributed in a second, typically refractory, transition metal (such as W) matrix at ambient pressures, including blending a first predetermined amount of first transition metal oxide powder (such as ZrO2) with a second predetermined amount of second transition metal carbide powder (such as WC powder). Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body.

Abstract: An earth-boring drill bit having a bit body with a cutting component formed from a tungsten carbide composite material is disclosed. The composite material includes a binder and tungsten carbide crystals comprising sintered pellets. The composite material may be used as a hardfacing on the body and/or cutting elements, or be used to form portions or all of the body and cutting elements. The pellets may be formed with a single mode or multi-modal size distribution of the crystals.

Abstract: A method for manufacturing a cutting insert green body having undercuts includes providing a die cavity formed in closed top and bottom dies; closing a bottom of the die cavity by a bottom punch accommodated in a punch tunnel formed in the bottom die; filling the die cavity with a pre-determined amount of sinterable powder; moving a top punch towards the die cavity through a punch tunnel formed in the top die; compacting the powder by urging the top and bottom punches towards each other, thereby forming the green body; and moving the top die and punch away from the bottom die and punch, thereby enabling removal of the formed green body. An apparatus for manufacturing a cutting insert green body having undercuts includes top and bottom dies which abut each other and top and bottom punches which slide in their respective dies.

Abstract: The present invention relates to a method of making tungsten carbide powder by dissolving at least one organic or inorganic metal salt or compound of at least one of the groups IV, V, and VI of the periodic system preferably Cr, V, Mo and W in at least one polar solvent. Powder of WO3 is added to the solution, the solvent is evaporated, the remaining powder is heat treated in reducing atmosphere, mixed with carbon and carburized.

Abstract: The disclosed is an ultra-hard composite material. The method for manufacturing the ultra-hard composite material includes mixing a metal carbide powder and a multi-element high-entropy alloy powder to form a mixture, green compacting the mixture, and sintering the mixture to form the ultra-hard composite material. The described multi-element high-entropy alloy consists of five to eleven principal elements, with every principal element occupying a 5 to 35 molar percentage of the alloy.

Abstract: This invention is a manual sharpening device for knife blades that creates a micro-serrated edge on the cutting edge of a knife (microscopic saw). There are two types of knife blades on the world market: plain (flat cutting surface) and serrated (undulated cutting surface, also known as saw knives). Each has a wide range of shapes and sizes for various applications. This sharpening tool allows the user to create a cutting edge on any knife that combines the effects of the plain and serrated edge and thereby expands the potential applications of any knife.

Abstract: In a solid precursor evaporation system configured for use in a thin film deposition system, such as thermal chemical vapor deposition (TCVD), a method for preparing one or more trays of solid precursor is described. The solid precursor may be formed on a coating substrate, such as a tray, using one or more of dipping techniques, spin-on techniques, and sintering techniques.

Abstract: The present invention relates to a cutting tool insert for parting, grooving and threading in steel and stainless steels comprising a substrate and a coating. The substrate comprises WC, from about 7.5 to about 10.5 wt-% Co, from about 0.7 to about 1.1 wt-% Cr and from about 100 to about 300 ppm Ti. Ti may partly be replaced by Ta to a weight ratio Ti/Ta of equal to or more than about 0.8. The coating comprises two (Ti,Al)N-layers with different Al/Ti-ratios: an inner AlyTi1-yN-layer with y equals from about 0.4 to about 0.67 with a thickness of from about 0.3 to about 2.5 ?m and an outer AlwT1-wN layer with w equals from about 0.15 to about 0.35 with a thickness of from about 0.5 to about 5.0 ?m.

Abstract: A weldable ultrahard insert can include an ultrahard working layer and a weldable metal layer metallically bonded with the working layer. The ultrahard working layer can be any ultrahard material such as PCD, PCBN, metal carbide, ceramic, diamond, or the like. The weldable ultrahard inserts can be formed by charging a reaction vessel with ultrahard materials, including precursors thereof, and placing a weldable metal layer in the reaction vessel with an optional intermediate layer. The assembly can be subjected to a pressure and a temperature sufficient to metallically bond the weldable metal layer to the ultrahard material. The weldable layer is formed as part of the insert in situ which facilitates subsequent welding of the insert to a tool substrate without risking damage to the ultrahard material.

Abstract: In accordance with the present invention, a method for manufacturing tungsten carbide components is provided. The method includes forming a composite material out of tungsten carbide powder and binder powder, pressing the composite material into a plurality of components, heating the plurality of components, optionally under pressure, to liquefy the binder, cooling the plurality of components until the binder solidifies, optionally grinding each of the plurality of components to a desired size, and cascading the plurality of components in a cascading machine under high energy conditions.

Abstract: A rotary cone bit, having a functionally-engineered surface of this invention, comprises a bit body having at least one leg extending therefrom, and a cone that is rotatably disposed on the leg. The cone typically comprises a plurality of cutting elements that project outwardly therefrom. The cutting elements comprises a cermet material selected from the group consisting of refractory metal carbides, nitrides, borides, carbonitrides and mixtures thereof. A functionally-engineered material is disposed over a surface portion of at least one of the cutting elements to form a wear resistant surface thereon. The wear resistant surface has a hardness that is different than that of the underlying cutting element. The wear resistant surface is provided by forming a conformable material mixture by combining one or more powders selected from the group consisting of cermets, carbides, borides, nitrides, carbonitrides, refractory metals, Co, Fe, Ni, and combinations thereof, with an applying agent.

Abstract: A cemented carbide including WC, a binder phase based on Co, Ni or Fe, and gamma phase, in which said gamma phase has an average grain size <1 ?m. A method of making the cemented carbide is provided in which the powders forming gamma phase are added as mixed cubic carbides of one or more of Ti, Ta, Nb, Zr, Hf and V, and a ratio, fWC, between an amount of WC (in mol fraction of WC) and an equilibrium gamma phase WC content at a sintering temperature (in mol fraction WC) is given by fWC=xWC/xeWC, wherein fWC is 0.6 to 1.0.

Abstract: Polycrystalline diamond (PCD) carbide composites of this invention have a microstructure comprising a plurality of granules formed from PCD, polycrystalline cubic boron nitride, or mixture thereof, that are distributed within a substantially continuous second matrix region that substantially surrounds the granules and that is formed from a cermet material. In an example embodiment, the granules are polycrystalline diamond and the cermet material is cemented tungsten carbide. PCD carbide composites of this invention display improved properties of fracture toughness and chipping resistance, without substantially compromising wear resistance, when compared to conventional pure PCD materials.

Abstract: A sintered cemented carbide body (e.g., a cutting tool) and a method of making the same. The sintered cemented carbide body includes tungsten carbide, a binder phase of at least one metal of the iron group or an alloy thereof, and one or more solid solution phases. Each one of the solid solution phases has at least one of the carbides and carbonitrides of a combination of zirconium, niobium, and tungsten. The method includes the steps of providing a powder mixture that contains tungsten carbide, a binder metal powder comprising at least one metal of the iron group or an alloy thereof, and at least one of the carbides and carbonitrides of both zirconium and niobium including a powder of the carbides or carbonitrides of zirconium and niobium, forming a green compact of said powder mixture, and vacuum sintering or sinter-HIP said green compact at a temperature of from 1400 to 1560° C.

Abstract: The present invention relates to a method of producing tungsten carbide by gas phase direct carburization of a tungsten-oxide containing starting material, wherein the starting material is reacted with a reaction gas at an increased temperature. The starting material is first heated to a first temperature greater than or equal to 600° C., before reacting with a reaction gas while increasing the temperature to a second temperature that does not exceed 850° C., wherein the reaction gas is selected from the group consisting of CO and a COH2 gas mixture comprising up to 20% by volume H2.

Abstract: Preparation, handling, and spray drying, in an economic and environmentally-friendly way, of slurries for the production of tungsten carbide based hard metal tools or components by the powder injection molding or extrusion route is disclosed. The slurry used is based on ethanol-water and contains metal carbide and metallic raw materials as well as stearic acid and a low concentration of polyethylenimine (PEI). The concentration of PEI is 0.01–1 wt % of the raw material weight. This combination results in low-viscous slurries, which require less use of ethanol, energy, manpower, and equipment time in their preparation, handling, and spray drying. The invention also relates to the powder obtained by using the method.

Abstract: There is provided a method of making a composite abrasive compact which comprises an abrasive compact bonded to a substrate. The abrasive compact will generally be a diamond compact and the substrate will generally be a cemented carbide substrate. The composite abrasive compact is made under known conditions of elevated temperature and pressure suitable for producing abrasive compacts. The method is characterised by the mass of abrasive particles from which the abrasive compact is made. This mass has three regions which are: (i) an inner region, adjacent the surface of the substrate on which the mass is provided, containing particles having at least four different average particle sizes; (ii) an outer region containing particles having at least three different average particle sizes; and (iii) an intermediate region between the first and second regions.

Abstract: A formed body prepared by compacting tungsten powders is embedded in a powder mixture capable of performing combustion synthesis, a part of the powder mixture is powerfully heated to ignite the part and perform combustion synthesis, by the heat of formation released, a temperature of a formed body is instantaneously elevated to induce a sintering reaction, and a high temperature state is retained to convert a whole of the formed body into sintered tungsten.

Abstract: W powders and C powders are mixed at a ratio of 1:1, the raw material mixed powder is compacted to prepare a formed body, the formed body is embedded into a powder mixture capable of performing combustion synthesis, a part of the powder mixture is powerfully heated to ignite the part and perform combustion synthesis, and according to heat of formation released, a reaction represented by W+C?WC is induced and the reaction is subjected to combustion synthesis to convert a whole of the formed body into sintered WC.

Abstract: The present invention relates to economic and environment-friendly slurries and their preparation, handling, and spray drying for the production of cemented carbide based hard metals. The slurry is ethanol-water based and contains metallic and metal carbide raw materials as well as polyethylene glycol (PEG) and a very low concentration of polyethylenimine (PEI). The concentration of PEI is 0.01-<0.1% of the raw material weight. As a result, low-viscous slurries are produced which require less use of ethanol, energy, manpower and equipment time in their preparation, handling, and spray drying.

Abstract: A powder blend for use in laser sintering and a method for forming tough, strong, wear-resistant, corrosion-resistant infiltrated metal products are provided. The powder blend comprises a steel alloy, a polymeric binder and a high melting temperature fine particulate which are blended together, then applied layer by layer to a working surface in a laser sintering system, exposed a layer at a time to fuse together the powder until a green part of high strength is formed, and then the green part is infiltrated with a metal infiltrant in a non-reducing gas atmosphere at an effective temperature for an effective period of time. The preferred steel is a mild steel alloy.

Abstract: A nanostructured tungsten carbide bulk material, sintered from tungsten carbide and metal such as cobalt nano-powders, comprises a tungsten carbide and a metallic binder such as cobalt phases. The tungsten carbide phase has nanostructures comprising a plurality of dislocations, twins, stacking faults, dislocation cells, nano-subgrains with preferred orientation or texture, or a combination thereof.

Abstract: The invention proposes a fine grained sintered cemented carbide containing chromium and based on WC and a binder based on Co or CoNiFe, and having at least one additional phase comprising at least one carbide or mixed carbide of tantalum. For improving the high-temperature properties while simultaneously maintaining a good trade-off between hardness and bending strength, it is proposed that the sintered cemented carbide contains approximately 0.3 to 4% Ta, as related to the total mass of the sintered cemented carbide, that the WC has a grain size of between 0.1 and 1.3 &mgr;m, that the binder phase contains the metals W, Cr and Ta, dissolved in solid solution, and that the at least one additional phase comprises a TaC phase visible by optical microscopy. The invention further relates to a powder-metallurgical process for manufacturing the sintered cemented carbide and to the use of the sintered cemented carbide for manufacturing cutting tools having improved high-temperature properties.

Abstract: A method for the synthesis of method for the manufacture of carbide cermet powders, comprises high energy ball milling a mixture of precursor powders and a carbon source, followed by annealing the milled powder mixture. The precursor powders are selected from materials suitable for the formation of cermets, for example silicon, titanium, thorium, hafnium, vanadium, chromium, tungsten, tantalum, niobium, and zirconium-containing materials. The precursors further include a source of carbon. Tungsten cobalt carbide powders produced by this method are submicron-sized (0.2 to 0.4 microns) with internal nanograins (10 to 40 nanometers in diameter).

Abstract: A process of making an article of a tungsten-carbide-cobalt alloy with or without an additive of one or more of tantalum, cobalt-nickel, nickel-tantalum, tantalum-carbide, titanium-carbide, niobium-carbide, chromium-carbide, titanium-nitride and diamond dust. The method includes forming a homogeneous mixture of polygonal-shaped powder tungsten-carbide-cobalt and a polygonal-shaped powder additive and a binder including wax and a high molecular weight polyolefin polymer and injecting the mixture under heat and pressure into a metal injection mold to form a green preform of the article. The green preform is immersed in a linear hydrocarbon or a halogenated hydrocarbon or mixtures to dissolve and remove the wax and convert the green preform into a brown preform which is sintered to remove the remainder of the binder and to densify the brown preform into an article having a density not less than 98%. Various tungsten-carbide articles are disclosed.

Abstract: A method of cryogenic treatment of tungsten carbide containing cobalt. A first step involves pre-treating tungsten carbide with microwave sintering, thereby changing the properties of the tungsten carbide. A second step involves lowering the temperature of the microwave sintered tungsten carbide gradually to cryogenic levels. A third step involves raising the temperature of the microwave sintered tungsten carbide gradually back to ambient temperatures. The described combination of microwave sintering and cryogenic treatment produces significant improvement in impact resistance, erosion and corrosion resistance and wear rate.

Abstract: A thermal spray method for the fabrication of ceramic/metal and ceramic/ceramic hardcoating for wear applications. The method makes use of feedstock powder, composed of micron-scale aggregates of hard phase material particles that are either mixed or coated with a readily fusible nano-scale binder phase material. Thus, during thermal spraying, the nanostructured material undergoes rapid melting while the aggregated material is heated but not necessarily melted. A dense coating is formed when the molten nano-material fills the available pore spaces between the heated and softened aggregates, providing a strong and tough matrix for the consolidated material. Optimal wear properties are achieved when the volume fraction of aggregated particles is high, typically in the range of 0.5-0.9. Aggregated material may be composed of one, two or more particles of difference sizes and/or compositions, with particle size distribution that gives high packing density for the hard phase.

Abstract: There is now provided a cemented carbide grade for rock excavation purposes with 88-96 weight % WC, preferably 91-95% weight % WC, with a binder phase consisting of only cobalt or cobalt and nickel, with a maximum of 25% of the binder being Ni, possibly with small additions of rare earth metals, such as Ce and Y, up to a maximum of 2% of the total cemented carbide. The WC grains are rounded because of the process of coating the WC with cobalt, and not recrystallized or showing grain growth or very sharp cornered grains like conventionally milled WC, thus giving the bodies surprisingly high thermal conductivity. The average grain size should be from 8-30 &mgr;m, preferably from 12-20 &mgr;m. The maximum grain size does not exceed 2 times the average value and no more than 2% of the grains found in the structure are less than half of the average grain size.

Abstract: A cemented carbide insert of a first grade has at least one cutting point consisting of a cemented carbide of a second grade with different composition and/or grain size with an uneven transition zone between the first and second grade.

Abstract: The presently claimed invention relates to a method of making a PcBN cutting tool insert. The method includes the following steps: mixing raw material powders, (e.g., cBN, hBN, TiC, TiN, Ti(C,N), WC, W, C, Co, Co2Al9, Al AlN, Al2O3) with a liquid (e.g., ethanol) and an agent (e.g., polyethylene glycol, PEG) to form a homogeneous slurry with the desired composition; forming spherical powder agglomerates, typically 100 &mgr;m in diameter, preferably by spray drying; pressing said agglomerates to form a body of desired dimensions and density using conventional tool pressing technology; removing the agent from the powder at a suitable temperature and atmosphere; raising the temperature to 1000-1350° C. in vacuum; solid state sintering the body at 1000-1350° C. in vacuum, for 1-90 minutes to form a body with 35-55 vol % porosity; optionally, adding 0.

Abstract: The present invention relates to a method of making a cemented carbide by mixing powder of WC and possibly other powders forming hard constituents and binder phase and pressing agent, drying, pressing and sintering whereby; the mixing is wet mixing with no change in grain size or grain size distribution of the hard constituent powders; the WC grains are coated with binder metal and deagglomerated prior to the mixing. The sintering is made by microwave sintering at 1325-1410° C. with a holding time of 5-15 min. As a result a cemented carbide with improved properties is obtained.

Abstract: A nanostructured tungsten carbide bulk material, sintered from tungsten carbide and metal such as cobalt nano-powders, comprises a tungsten carbide and a metallic binder such as cobalt phases. The tungsten carbide phase has nanostructures comprising a plurality of dislocations, twins, stacking faults, dislocation cells, nano-subgrains with preferred orientation or texture, or a combination thereof.

Abstract: W powders and C powders are mixed at a ratio of 1:1, the raw material mixed powder is compacted to prepare a formed body, the formed body is embedded into a powder mixture capable of performing combustion synthesis, a part of the powder mixture is powerfully heated to ignite the part and perform combustion synthesis, and according to heat of formation released, a reaction represented by W+C→WC is induced and the reaction is subjected to combustion synthesis to convert a whole of the formed body into sintered WC.

Abstract: A fracture and wear resistant rock bit is disclosed, which includes a bit body, and at least one roller cone disposed on the bit body adapted such that at least one row of cutting elements disposed on the at least one roller cone defines a gage row. At least one cutting element disposed on the gage row has a fracture toughness of at least 20 ksi (in)0.5 and a wear number of at least 1.5.

Abstract: Disclosed is a method of making a composite diamond having a cutting edge comprising a diamond compact bonded to a cemented carbide substrate, the diamond compact having a working surface, an edge of which provides the cutting edge, wherein the diamond compact comprises a first phase containing a polycrystalline mass of diamond particles and a second phase containing a diamond catalyst/solvent and ruthenium, which method includes the steps of providing a cemented carbide substrate, providing a layer of diamond particles on a surface of the substrate, providing a source of diamond catalyst/solvent and ruthenium, wherein the source of the diamond catalyst/solvent and ruthenium is the cemented carbide substrate.

Abstract: A corrosion and oxidation resistant cemented carbide contains WC and 6-15 wt. % binder phase whereby the binder phase contains 8-12 wt. % of a corrosion resisting addition with an average WC grain size of 3-10 &mgr;m. Cemented carbide is obtained with selection of a total carbon content of 6.13−((0.05±0.007)×binder phase content in wt. %).

Abstract: A dense cemented carbide product is described. The product is manufactured from WC with a grain size between 0.1 and 0.4 ¼ m, fine grain size cobalt and ruthenium powders. The product is used in PCB machining operations where the addition of 10-25% Ru to the binder phase offers up to 25% wear resistant incrases and up to 100% increase in chipping resistance in PCB routing compared to conventional materials (6% cobalt and 0.4 ¼ m grain size).

Abstract: The present invention relates to a method of making a cemented carbide comprising WC, 6-12 wt. % Co and 0.1-0.7 wt. % Cr, wherein the WC-grains are coated with Cr prior to mixing and no milling takes place during the mixing step. As a result a cemented carbide with improved properties is obtained.

Abstract: As there is disclosed a cemented carbide body comprising WC with an average grain size of <10 ?m in a binder phase. In the cemented carbide body the WC grains can be classified in at least two groups in which a group of smaller grains has a maximum grain size amax and a group of larger grains has a minimum grain size bmin and each group contains at least 10 % of the total amount of WC grains. According to the invention bmin?amax>0.5 ?m and the difference in grain size within each group is >1 ?m.

Abstract: The present invention relates to a method of making a cemented carbide body with a bimodal grain size distribution by powder metallurgical methods including wet mixing, without milling, of WC-powders with different grain size distributions with binder metal and pressing agent, drying, pressing and sintering. The grains of the WC-powders are classified in at least two groups, a group of smaller grains and a group of larger grains. According to the method of the present invention, the grains of the group of smaller grains are precoated with a growth inhibitor with or without binder metal.