Abstract: The present invention relates to a coated body such as a cutting tool insert comprising a wear resistant coating and a cemented carbide body particularly useful for the machining of cast iron parts by turning, milling or drilling at high speeds. The cemented carbide body consists of WC, 3.5-9 wt-% Co and <2 wt-% carbides of Ta, Ti and Nb. It has a core containing finely distributed eta phase islands and an intermediate zone 50-250 &mgr;m thick essentially free of eta phase and with nominal Co content whereby the binder phase in the intermediate zone is present as smaller original islands and larger islands transformed from original eta phase. These latter Co-islands therefore have a size and distribution essentially the same as that of the eta phase in the core. There may be present a thin surface zone free of eta phase with a Co content lower than the nominal Co-content.

Abstract: The present invention relates to coated silicon nitride based cutting tools and a method of making the same. By a carburizing heat treatment prior to the deposition of the coating, an improved bonding strength of the coating is obtained. A continuous or semicontinuous transition zone of 2-10 &mgr;m thickness is formed between the substrate and the inner layer of the coating in which transition zone the glass phase is replaced by the material of the inner layer.

Abstract: The present invention relates to a method for sintering of a silicon nitride based material using gas pressure sintering technique. It has been found that using a sintering atmosphere containing nitrogen and 0.1-10 vol-% carbon monoxide a cutting tool material is obtained with improved properties, particularly increased edge toughness, when machining heat resistant alloys.

Abstract: A sintered body of titanium-based carbonitride alloy according to the invention comprises carbonitride hard constituents in 5-25% binder phase where the hard constituents contain, in addition to Ti, one or more of the metals Zr, Hf, V, Nb, Ta, Cr, Mo and/or W and the binder phase is based on cobalt and/or nickel. The sintered body has at least one outer surface with a <50 .mu.m thick surface layer of a titanium-rich cubic carbonitride. Below this layer there is a <100 .mu.m thick binder phase enrichment zone. The binder phase content can be >1.2 of that in the inner part of the body D. Under the binder phase enrichment zone, there is a <250 .mu.m thick binder phase depleted zone C. The binder phase content in this zone has a lowest level <0.9 of the binder phase content in the inner part of the body D.Such sintered bodies are manufactured by heat treatment in an atmosphere of N.sub.2 and/or NH.sub.3 possibly in combination with at least one of CH.sub.4, CO and CO.sub.2 at 1100.degree.-1350.

Abstract: The present invention relates to a sintered body for chip forming machining containing at least one hard constituent comprising a carbide, nitride and/or carbonitride of a metal of group IVB, VB or VIB in the periodical system and a binder metal based upon Co, No and/or Fe, in which the body comprises a core containing eta-phase or an intermediate phase, substantially free of carbon and/or nitrogen surrounded by a hard constituent- and binder phase-containing surface zone, free of said eta-phase or intermediate phase.

Abstract: An improved process for the production of coated cemented carbide products is disclosed. A cemented carbide substrate is treated to form a metal carbide, nitride or carbonitride coating. The coated substrate is heat treated at a temperature close to or near the melting point of the binder metal of the cemented carbide to diffuse elements from the substrate into the coating. An intermediate (second) metal carbide, nitride or carbonitride coating is thereafter applied and the portion of the second is oxidized, nitrided or sulfided without detrimentally affecting the adherence of the second coating. Thereafter, a wear-resistant oxide (e.g., aluminum oxide) coating is applied to form the improved coated carbide product.

Abstract: An improved process for the production of coated cemented carbide products is disclosed. A cemented carbide substrate is treated to form a metal carbide, nitride or carbonitride coating. During the last part of this treatment or subsequent thereto, a sulfur-and/or nitrogen-containing gas is added to the atmosphere to form a sulfide-and/or nitride - containing layer on the coating. Thereafter, a wear-resistant oxide (e.g., aluminum oxide) coating is applied to form the improved coated cemented carbide product.

Abstract: The present invention relates to a sintered body for chip forming machining containing at least one hard constituent comprising a carbide, nitride and/or carbonitride of a metal of group IVB, VB or VIB in the periodical system and a binder metal based upon Co, No and/or Fe, in which the body comprises a core containing eta-phase or an intermediate phase, substantially free of carbon and/or nitrogen surrounded by a hard constituent- and binder phase-containing surface zone, free of said eta-phase or intermediate phase.