Abstract: A small drill includes one chip-discharging flute which is helically formed in the exterior surface of a cutting portion of the small drill. The small drill also includes a flute-shaped portion which is formed in the front region of the chip-discharging flute in the rotating direction, which is connected to the chip-discharging flute, and which is open at the exterior surface of the cutting portion. The core diameter ratio d/D, in percent, of the small drill is set to 60% or more, and a margin angle ? thereof is set to 120° or more.

Abstract: A small drill includes one chip-discharging flute which is helically formed in the exterior surface of a cutting portion of the small drill. The small drill also includes a flute-shaped portion which is formed in the front region of the chip-discharging flute in the rotating direction, which is connected to the chip-discharging flute, and which is open at the exterior surface of the cutting portion. The core diameter ratio d/D, in percent, of the small drill is set to 60% or more, and a margin angle &thgr; thereof is set to 120° or more.

Abstract: A cermet cutting tool, and process for producing the same, comprising a substrate formed from titanium carbo-nitride based cermet, and a hard coating layer of average thickness 0.5.about.20 .mu.m, formed onto the surface of the cermet substrate comprising a lower layer formed from at least one layer of a compound selected from the group consisting of titanium carbide (TiC), titanium nitride (TiN), titanium carbo-nitride (TiCN), titanium carbo-oxide (TiCO) and titanium carbo-oxi-nitride (TiCNO), and aluminum oxide (Al.sub.2 O.sub.3). Additionally, at least one of the layers comprising the hard coating layer is a titanium carbo-nitride layer, and at least one layer of this titanium carbo-nitride layer comprises a longitudinal growth crystal structure, and a further layer comprises a granular crystal structure. In the method of fabrication, chemical vapor deposition is performed using a reaction gas composed of 1.about.5% of TiCl.sub.4, 0.1.about.1% of CH.sub.3 CN, 0.about.25% of N.sub.

Abstract: A TiCN-based cermet cutting insert superior in toughness with improved wear resistance includes a binding phase and at least two hard dispersion phases. One of the hard dispersion phases includes one of a duplex and triplex structure having a core structure containing at least one of titanium carbonitride and a carbonitride solid solution of Ti and one of a V, Cr, Ti, Nb, Zr, W and Mo (hereinafter referred to as a (Ti,M)CN. The other hard dispersion phase includes a single structure wherein the core structure is composed of at least one of (Ti,M)CN or (Ti,M)CN and TiCN.

Abstract: A TiCN-based cermet cutting insert superior in toughness with improved wear resistance includes a binding phase and at least two of four hard dispersion phases. One of the two hard dispersion phases includes at least one of a duplex or triplex phase structure with a core of a composite carbonitride solid solution and a single-phase structure of a composite carbonitride solid solution. The other hard dispersion phase includes one of a hard dispersion phase of titanium carbonitride and a hard dispersion phase which includes a single-phase structure of titanium carbonitride.

Abstract: The present invention discloses a cermet cutting tool, and process for producing the same, comprising a substrate formed from titanium carbo-nitride based cermet, and a hard coating layer of average thickness 0.5.about.20 .mu.m, formed onto the surface of the cermet substrate comprising a lower layer formed from at least one layer of a compound selected from the group consisting of titanium carbide (TiC), titanium nitride (TIN), titanium carbo-nitride (TiCN), titanium carbo-oxide (TiCO) and titanium carbo-oxi-nitride (TiCNO), and aluminum oxide (Al.sub.2 O.sub.3). Additionally, at least one of the layers comprising the hard coating layer is a titanium carbo-nitride layer, and at least one layer of this titanium carbo-nitride layer comprises a longitudinal growth crystal structure.

Abstract: A TiCN-based cermet cutting insert superior in toughness with improved wear resistance includes a binding phase and at least two hard dispersion phases. One hard dispersion phases includes a core of TiCN while the other hard dispersion phases includes a core of a carbonitride solid solution of Ti and one of a V,Hf,Cr, Ta,Nb, Zr, W and Mo.

Abstract: There is disclosed a surface coated cermet blade member which includes a cermet substrate and a hard coating of an average thickness of 0.5 to 20 .mu.m formed thereon. The substrate contains, apart from unavoidable impurities, a binder phase of 5 to 30% by weight of at least one of cobalt, nickel, iron and aluminum, and a hard dispersed phase of a balance carbo-nitride of metals. The metals are titanium, tungsten and at least one of tantalum, niobium, vanadium, zirconium, molybdenum and chromium. The substrate includes a surface portion having a hardness greater than an interior portion. The hard coating may be composed of one or more coating layers. Each coating layer is formed of TiX or Al.sub.2 O.sub.3, where X denotes at least one element of carbon, nitrogen, oxygen and boron.

Abstract: A blade member for cutting-tools includes a cermet substrate which contains, apart from unavoidable impurities, a binder phase and a hard dispersed phase. The binder phase contains 5% to 30% by weight of cobalt and/or nickel. The hard dispersed phase contains a balance composite carbonitride of titanium and one or more of the elements tungsten, molybdenum, tantalum, niobium, hafnium and zirconium. The composite carbo-nitride satisfies the relationship 0.2.ltoreq.b/(a+b).ltoreq.0.7, where a and b denote atomic ratios of carbon and nitrogen, respectively. The substrate includes a hard surface layer in which the maximum hardness is present at a depth between 5 .mu.m and 50 .mu.m from a substrate surface thereof. The substrate surface has a hardness of 20% to 90% of the maximum hardness.

Abstract: A blade member for cutting-tools includes a cermet substrate which contains, apart from unavoidable impurities, a binder phase and a hard dispersed phase. The binder phase contains 5% to 30% by weight of cobalt and/or nickel. The hard dispersed phase contains a balance composite carbonitride of titanium and one or more of the elements tungsten, molybdenum, tantalum, niobium, hafnium and zirconium. The composite carbo-nitride satisfies the relationship 0.2.ltoreq.b/(a+b).ltoreq.0.7, where a and b denote atomic ratios of carbon and nitrogen, respectively. The substrate includes a hard surface layer in which the maximum hardness is present at a depth between 5 .mu.m and 50 .mu.m from a substrate surface thereof. The substrate surface has a hardness of 20% to 90% of the maximum hardness.

Abstract: An end mill formed of a tungsten carbide-base sintered hard alloy comprising a binder phase including a Co-base alloy, and a hard disperse phase consisting essentially of WC in proportions of:binder phase: 6-23 wt. %, andhard disperse phase: 77-94 wt %,the binder phase having a composition of:Cr: 1-15 wt. %,W: not more than 5 wt. %, andthe balance of Co and inevitable impurities, the hard disperse phase having a mean grain size of 0.5-2 .mu.m.

Abstract: A cermet has a hard phase and a binder phase. The hard phase is formed by about 70% to about 95% by weight of elements including titanium, tantalum, tungsten, carbon and nitrogen. The elements have atomic ratios so as to satisfy the relationships of 0.05.ltoreq.b/(b+a).ltoreq.0.20, 0.04.ltoreq.c/(c+a).ltoreq.0.20 and 0.15.ltoreq.y/(x+y).ltoreq.0.60, where a, b, c, x and y denote atomic ratios of titanium, tantalum, tungsten, carbon and nitrogen, respectively. The binder phase is formed by about 5% to about 30% by weight of at least one metal of cobalt and nickel. Additionally, there is disclosed a process for producing such a cermet.