Abstract: An insert chip of an oil-drilling tricone bit includes an insert-chip substrate made of a cemented carbide of a first composition, and further includes a cemented carbide coating layer constituted of at least two stacked coating layers made of a cemented carbide of a composition different from the first composition. The cemented carbide coating layer covers the whole of a cutting edge of the insert-chip substrate. The coating layers each have a thickness, at a tip portion of the cutting edge, in a range from 0.1 mm to 2.5 mm, and the total thickness of the cemented carbide coating layer is in a range from 1 mm to 5 mm. The coating layers include an outermost cemented carbide layer and at least one intermediate coating layer in addition to the outermost cemented carbide layer, and the outermost cemented carbide layer has a hardness higher than that of the at least one intermediate coating layer and of the insert-chip substrate.

Abstract: A coated diamond which is dense and excellent in adherence and enables diamond to exhibit its superior characteristics, a manufacturing method and a composite material of the coated diamond are achieved. The coated diamond includes a diamond (1) and an SiC film (2) coating the diamond (1). The SiC mentioned above is substantially formed of &bgr;-SiC and a value of ratio I (220)/I (111) is at least 0.38 and at most 0.55, I (220) representing peak intensity of Miller index (220) of SiC and I (111) representing peak intensity of Miller index (111) thereof.

Abstract: An insert chip of an oil-drilling tricone bit includes an insert-chip substrate made of a cemented carbide of a first composition, and further includes a cemented carbide coating layer constituted of at least two stacked coating layers made of a cemented carbide of a composition different from the first composition, the cemented carbide coating layer covering the whole of a cutting edge of the insert-chip substrate. The coating layers each have a thickness, at a tip portion of the cutting edge, ranging from 0.1 mm to 2.5 mm and, the total thickness of the cemented carbide coating layer ranges from 1 mm to 5 mm. The coating layers include an outermost cemented carbide layer and at least one coating layer besides the outermost cemented carbide layer and the outermost cemented carbide layer has a hardness higher than that of that at least one coating layer and of the insert-chip substrate.

Abstract: Amorphous carbon coated tools having excellent wear-resistant and anti-adhesion features and methods of producing the same are provided.

Abstract: An amorphous carbon coated tool includes a base material of WC base cemented carbide, and an amorphous carbon film formed on this base material. The cobalt content in the base material is at least 12% by mass. The maximum thickness of the amorphous carbon film is at least 0.05 &mgr;m and not more than 0.5 &mgr;m at the cutting edge. The amorphous carbon film is deposited with graphite as the source material by physical vapor deposition in an atmosphere substantially absent of hydrogen. The amorphous carbon film coated tool superior in wear resistance and adhesion resistance is preferably applicable to rotating tools such as drills, end mills and reamers, indexable inserts used for milling cutters and turning tools, and cutting-off tools such as cutters, knives, or slitters.

Abstract: In a cemented carbide, at least one compound 3 including a carbide, a nitride or carbo-nitride of at least one component selected from IVa, Va and VIa group elements or a solid solution thereof exists in at least some WC crystal grains 1. Preferably the compound 3 is in the form of compound grains 3 comprising a carbide, a nitride or a carbo-nitride of Ti, Zr, Hf or W or a solid solution thereof, having an average grain diameter smaller than 0.3 &mgr;m. The compound grains make up at most 10% of the cross-sectional area of the WC crystal grains that contain the compound grains, while at least 10% of the total cross-sectional area of the cemented carbide is made up of such WC crystal grains that contain the compound grains.

Abstract: The principal object of the present invention is to provide a coated cemented carbide tool whose both properties of breakage resistance and wear resistance are improved and whose life is lengthened. The present invention has been made to achieve this object and is related with a coated cemented carbide cutting tool comprising a substrate consisting of a matrix of WC and a binder phase of an iron group metal and a plurality of coated layers provided on a surface of the substrate, in which (a) an innermost layer, adjacent to the substrate, of the coated layers consists essentially of titanium nitride having a thickness of 0.

Abstract: A coated hard metal for a cutting tool is excellent in wear resistance and chipping resistance. The coated hard metal includes a hard coating layer on a surface of a base material of cemented carbide or cermet. The hard coating layer includes an inner layer (2) on the base material (1), an intermediate layer (3) on the inner layer (2) and an outer layer (4) on the intermediate layer (3). The inner layer (2) consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The intermediate layer (3) consists of Al2O3 or ZrO2. The outer layer (4) consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The thickness of the inner layer (2) is 0.1 to 5 &mgr;m, the thickness of the intermediate layer (3) is 5 to 50 &mgr;m in the case of it being an Al2O3 layer and 0.5 to 20 &mgr;m in the case of it being a ZrO2 layer, and the thickness of the outer layer (4) is 5 to 100 &mgr;m.

Abstract: A material to be cut has a face to be cut with a cutting tool, and a cutout which temporarily brings the cutting tool into a noncontact state. Images of the cutting tool during the period when it attains an exposed state by passing over the cutout are captured with a camera mechanism at an interval of a predetermined delay time .tau.. A plurality of image information items obtained by these capturing operations include temperature change information of each location as the cutting tool gradually passes from the point of instant when it enters the cutout. Therefore, the image information items are arranged in relation to the exposure time from the point of instant, and a two-dimensional temperature distribution of the cutting tool at the point of instance is computed according to the tendency of change in image information.

Abstract: A coated hard metal tool includes a hard metal base material having an edged part on an insert ridge portion defining a connecting portion between a flank and a rake face, and a coating film applied to a surface of the hard metal base material. The coating film has a surface-treated part on the insert ridge portion. The coating film is so formed that Rc1/(Rs1+d)<1.0 and Rc2/(Rs2+d)>1.

Abstract: In a composite material manufactured by connecting a sintered body to a surface of a metal substrate, the connection strength under a high temperature is increased, stress relaxation in the composite material is attained, and the strength, wear resistance and corrosion resistance are improved. The sintered body has a multilayer structure having layers with different compositions, i.e. compositions that vary or differ in a direction perpendicular to the connection surface, and the volume relation between the respective layers of the sintered body and the substrate is (substrate volume.times.0.2).gtoreq.(sintered body volume/number of layers), while the thickness of each layer is at least 0.2 mm and not more than 5 mm.

Abstract: A sintered body having diamond grains dispersed and held in a matrix of cemented carbide or cermet is obtained by direct resistance heating and pressurized sintering. The sintering is performed at a liquid phase generating temperature in a short time, so that the diamond grains are not directly bonded to each other. Thus, a superhard composite member that has excellent hardness and wear resistance can be obtained without employing an ultra high-pressure vessel.

Abstract: A coated hard metal for a cutting tool is excellent in wear resistance and chipping resistance. The coated hard metal includes a hard coating layer on a surface of a base material of cemented carbide or cermet. The hard coating layer includes an inner layer (2) on the base material (1), an intermediate layer (3) on the inner layer (2) and an outer layer (4) on the intermediate layer (3). The inner layer (2) consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The intermediate layer (3) consists of Al.sub.2 O.sub.3 or ZrO.sub.2. The outer layer (4) consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The thickness of the inner layer (2) is 0.1 to 5 .mu.m, the thickness of the intermediate layer (3) is 5 to 50 .mu.m in the case of it being an Al.sub.2 O.sub.3 layer and 0.5 to 20 .mu.m in the case of it being a ZrO.sub.2 layer, and the thickness of the outer layer (4) is 5 to 100 .mu.m.

Abstract: An improved coated hard alloy tool having a substrate made of a hard alloy, and a multi-layer ceramic coating film provided on the surface of the substrate, the coating film including at least one oxide layer. The top several layers of the coating film are missing partially or completely in an area where the tool is brought into frictional contact with a workpiece. At least one oxide layer (such as Al.sub.2 O.sub.3 layer) is included in the missing layers. This increases wear resistance of the coated hard alloy tool.

Abstract: A coated cemented carbide comprising: a substrate comprising a WC-based cemented carbide containing 4 to 10 wt. % of Co as a binder phase; based on a ratio in a mirror-polished texture of a cross section of the cemented carbide, 70% or more of WC crystals as a hard phase being classified into either of a group of fine particles A having a particle size of from 0.1 to 1 .mu.m and a group of coarse particles B having a particle size of from 3 to 10 .mu.m, the area ratio S.sub.A /S.sub.B of the fine particles A to the coarse particles B being in a range of from 0.22 to 0.45; and a coating layer disposed on a surface of the cemented carbide and having a total thickness in a range of from 5 to 100 .mu.m. The coating layer comprises at least one layer comprising at least one selected from the group consisting of: carbides, nitrides, carbonitrides, oxycarbides, and boronitrides of Ti, Zr, and/or Hf; and at least one layer comprising at least one selected from the group consisting of: Al.sub.2 O.sub.

Abstract: An improved coated hard alloy tool having a substrate made of a hard alloy, and a multi-layer ceramic coating film provided on the surface of the substrate, the coating film including at least one oxide layer. The top several layers of the coating film are missing partially or completely in an area where the tool is brought into frictional contact with a workpiece. At least one oxide layer (such as Al.sub.2 O.sub.3 layer) is included in the missing layers. This increases wear resistance of the coated hard alloy tool.

Abstract: A tool or tool insert is formed of a silicon nitride sintered body which contains silicon nitride as well as a sintering aid and is sintered under a pressurized atmosphere. Freely grown .beta.-Si.sub.3 N.sub.4 including .beta.'-SIALON is removed from its sintering surface by steps other than grinding. A tool of a surface-coated silicon nitride sintered body is formed by coating the surface of a base material, which is formed in a manner similar to the above, with a layer of carbide of Ti or the like having a thickness of 0.1 to 10 .mu.m and/or a layer of Al.sub.2 O.sub.3 having a thickness of 0.4 to 10 .mu.m. Tools or inserts formed by a silicon nitride sintered body and the same tools provided with a surface coating have an excellent wear resistance as well as toughness and can be manufactured at a low cost since grinding is avoided.

Abstract: A tool comprised of a silicon nitride sintered body which is excellent in toughness as well as wear resistance can be provided in an economical manner. The novel feature of the tool is that the silicon nitride crystal grains comprise 50 to 90% by volume of hexagonal pillar crystals having a minor axis of at most 1.0 .mu.m and 5 to 30% by volume of hexagonal pillar or columnar crystals having a minor axis of at least 1.5 .mu.m. As the silicon nitride starting powder, there is preferably used a mixture of at least two silicon nitride powders prepared by the imide decomposition method, direct metallic silicon nitriding method and silica reducing method.

Abstract: A drill bit of a diamond-coated sintered body has a substrate mainly composed of Si.sub.3 N.sub.4 or SiC. At least a wear portion of the bit is coated with a diamond layer. If the bit is of the throw-away kind, an insert is removably secured to a shank. At least the insert or a wear portion thereof is coated with a diamond layer. The sintered body contains a prescribed amount of a sintering assistant or aid selected from MgO, Y.sub.2 O.sub.3 and the like. The diamond coating layer has a thickness of at least 0.1 .mu.m.