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: According to the present invention there is provided a method of making a finegrained tungsten carbide—cobalt cemented carbide comprising mixing, milling according to standard practice followed by sintering. By introducing nitrogen at a pressure of more than 0.5 atm into the sintering atmosphere after dewaxing but before pore closure a grain refinement including reduced grain size and less abnormal grains can be obtained.

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: According to the present invention there is provided a method of making a finegrained tungsten carbide—cobalt cemented carbide comprising mixing, milling according to standard practice followed by sintering. By introducing nitrogen at a pressure of more than 0.5 atm into the sintering atmosphere after dewaxing but before pore closure a grain refinement including reduced grain size and less abnormal grains can be obtained.

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: The present invention relates to a coated cemented carbide insert with a binder phase enriched surface zone. The WC-grains have an average grain size in the range 1.0-3.5 &mgr;m, preferably 1.3-3.0 &mgr;m and the number of WC-grains larger than 2 times the average grain size is less than 10 grains/cm2 measured on a representative polished section 0.5 cm2 large, preferably less than 5 grains/cm2, and the number larger than 3 times the average grain size is less than 5 grains/cm2, preferably less than 3 grains/cm2. The cemented carbide is made by powder metallurgical methods and is in particular characterized in that the cooling rate, CR, from the sintering temperature, ST, exhibits the relationship 10<CR·(ST-1300)/1000<17.

Abstract: One or more metal salts of at least one iron group metal containing organic groups are dissolved in at least one polar solvent and complex bound with at least one complex former comprising functional groups in the form of OH or NR3, (R═H or alkyl). In addition, at least one insoluble, reducible salt of at least one iron group metal is suspended in the solution. Hard constituent powder and, optionally, a soluble carbon source are added to the solution. The solvent is evaporated and the powder mass is heat treated in inert and/or reducing atmosphere. As a result, a powder mixture is obtained which, after addition of a pressing agent, can be compacted and sintered according to standard practice to form a body containing hard constituents in a binder phase.

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.

Abstract: The present invention relates to a method of making a cemented carbide with submicron WC grain size with a powder metallurgical technique including milling, pressing and sintering. The method includes milling all components except WC for about three hours, then adding the WC powder and milling for about ten additional hours. In this way a cemented carbide powder with acceptable low compacting pressure is obtained.

Abstract: There is disclosed a cemented carbide insert with excellent properties for machining of steels and stainless steels. The cemented carbide comprises WC and 4-25 wt-% Co. The WC-grains have an average grain size in the range 0.2-3.5 &mgr;m and a narrow grain size distribution in the range 0-4.5 &mgr;m. According to the method of the invention a cemented carbide cutting tool insert is made by mixing powders of WC, TiC, TaC and/or NbC, binder metal and pressing agent, drying preferably by spray drying, pressing to inserts and sintering. The method characterised in that a deagglomerated WC-powder with a narrow grain size distribution is used, that the powders of TiC, TaC and/or NbC are deagglomerated and that the mixing is wet mixing with no change in grain size or grain size distribution.

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 &mgr;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 &mgr;m and the difference in grain size within each group is >1 &mgr;m.

Abstract: One or more organic or inorganic metal salts or compounds of at least one of the groups IV, V and VI of the periodic system, particularly V, Cr, Mo and W, optionally together with one or more organic iron group metal salts, are dissolved in at least one polar solvent and complex bound with at least one complex former comprising functional groups in the form of OH or NR.sub.3, (R=H or alkyl). Hard constituent powder and optionally soluble carbon source are added to the solution. The solvent is evaporated and the remaining powder is heat treated in an inert and/or reducing atmosphere. As a result, coated hard constituent powder is obtained, which after addition of a pressing agent and optionally with other coated hard constituent powders and/or carbon to obtain the desired composition, can be compacted and sintered according to standard practice.

Abstract: One or more metal salts of at least one of Co, Ni and/or Fe is dissolved/suspended in water. To the solution/suspension is added at least one hard constituent powder to form a slurry. The solvent is evaporated, preferably by spray drying, and the resultant powder is heat treated in a reducing atmosphere. As a result, a coated hard constituent powder is obtained which, after addition of a pressing agent, can be compacted and sintered according to standard practice. In addition to or instead of said salt of Co, Ni and/or Fe, a soluble salt of Mo and/or W can be used.

Abstract: There is now provided a cemented carbide button for rock drilling comprising a core and a surface zone surrounding the core whereby both the surface zone and the core contains WC (.alpha.-phase) and a binder phase based on at least one of cobalt, nickel or iron and that the core in addition contains .eta.-phase. In addition, in the inner part of the surface zone situated close to the core, the cobalt content is higher than the nominal content of cobalt and the cobalt content in the outermost part of the surface zone is lower than the nominal and increases in the direction towards the core, up to a maximum usually at the .eta.-phase core. The grain size distribution of the hard constituent in the zone with high cobalt content and in the .eta.-phase core is narrow in contrast to a button of the prior art in which the grain size distribution of the hard constituent in the zone with high cobalt content and the .eta.-phase core is wide.

Abstract: There is disclosed a cemented carbide insert with excellent properties for machining of steels and stainless steels. The cemented carbide comprises WC and 4-25% Co. The WC-grains have an average grain size in the range 0.2-3.5 ?m and a narrow grain size distribution in the range 0-4.5 ?m. According to the method of the invention a cemented carbide cutting tool insert is made by mixing powders of WC, TiC, TaC and/or NbC, binder metal and pressing agent, drying preferably by spray drying, pressing to inserts and sintering. The method characterised in that a deagglomerated WC-powder with a narrow grain size distribution is used, that the powders of TiC, TaC and/or NbC are deagglomerated and that the mixing is wet mixing with no change in grain size or grain size distribution.

Abstract: The present invention relates to a method of making a cemented carbide with submicron WC grain size with a powder metallurgical technique including milling, pressing and sintering. The method includes milling all components except WC for about three hours, then adding the WC powder and milling for about ten additional hours. In this way a cemented carbide powder with acceptable low compacting pressure is obtained.

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.