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US 6,187,421 B1Granted
Coated tool of cemented carbide
AssigneeSumitomo Electric Industries, Ltd.
InventorsHideki Moriguchi, Akihiko Ikegaya, Kazuo Yamagata
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AssigneeSumitomo Electric Industries, Ltd.
InventorsHideki Moriguchi, Akihiko Ikegaya, Kazuo Yamagata
Estimating the term…
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 0.1 to 3 μm, (b) on a mirror-polished cross-sectional microstructure of the said tool, an average crack interval in the coated film on a ridge of a cutting edge and/or rake face is smaller than an average crack interval in the coated layer on a flank face, (c) at least 50% of the cracks in the coated film on the said ridge of the cutting edge and/or rake face have ends of the cracks in the said innermost titanium nitride layer, in a layer above the titanium nitride layer or in an interface between these layers and (d) an average crack length in the coated film on the said ridge of the cutting edge and/or rake face is shorter than an average film thickness on the flank face. According to the present invention, quantitatively specifying the crack intervals and positions of the ends of the cracks in the coated layer results in excellent breakage resistance as well as wear resistance.
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 0.1 to 3 μm, (b) on a mirror-polished cross-sectional microstructure of the said tool, an average crack interval in the coated film on a ridge of a cutting edge and/or rake face is smaller than an average crack interval in the coated layer on a flank face, (c) at least 50% of the cracks in the coated film on the said ridge of the cutting edge and/or rake face have ends of the cracks in the said innermost titanium nitride layer, in a layer above the titanium nitride layer or in an interface between these layers and (d) an average crack length of in the coated film on the said ridge of the cutting edge and/or rake face is shorter than an average coated film thickness on the flank face.
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 a substrate, in which (a) an innermost layer, adjacent to the substrate, of the coated layers consists essentially of titanium nitride having a thickness of 0.1 to 3 μm, which is further coated with at least one alumina layer of 0.5 to 10 μm, (b) on a mirror-polished cross-sectional microstructure of the tool, an average crack interval in the coated film on a ridge of a cutting edge is smaller than an average crack interval in the coated layer on a flank face, (c) at least 50% of the cracks in the coated film on the said ridge of the cutting edge have ends of the cracks, at the substrate side, in the said innermost titanium nitride layer, in a layer above the titanium nitride layer or in an interface between these layers, (d) an average crack length in the coated film on the said ridge of the cutting edge is shorter than an average coated film thickness on the flank face and (e) at least one of the said alumina layers is removed or polished on at least a part of the ridge of the cutting edge.
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 0.1 to 3 μm, which is further coated with titanium carbonitride layer of columnar structure with an aspect ratio of at least 5, having a thickness of 3 to 30 μm, and further is coated with at least one alumina layer with a thickness of 0.5 to 10 μm, (b) on a mirror-polished cross-sectional microstructure of the said tool, at least 50% of ends of cracks at the surface side in the coated film on a ridge of a cutting edge and/or rake face are not penetrated to the surface of the coated film, (c) at least 50% of the cracks in the coated film on the said ridge of the cutting edge and/or rake face have ends of the cracks, at the substrate side, in the said innermost titanium nitride layer, in a layer above the titanium nitride layer or in an interface between these layers and (d) an average crack length in the coated film on the said ridge of the cutting edge and/or rake face is shorter than an average coated film thickness on the flank face, (e) an average crack inerval in the said titanium carbonitride layer on the said ridge of the cutting edge and/or rake face is at most 10 μm and (f) an average crack interval in the said alumina film on the said ridge of the cutting edge and/or rake face is at least two times as large as an average crack interval in the said titanium carbonitride layer.
Dependencies are inferred from the claim text.