Coated cutting tool insert
AssigneeSeco Tools AB
InventorsAndreas Larsson, Anette Sulin, Lena Pettersson
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Abstract
Coated cemented carbide inserts (cutting tool), particularly useful for milling at high cutting speeds in steels and milling in hardened steels are characterised by a WC—Co cemented carbide containing NbC and TaC and a W-alloyed binder phase and a coating including a first, innermost layer of TiCxNyOz with equiaxed grains, a second layer of TiCxNyOz with columnar grains and at least one layer of Al2O3 composed primarily of the κ-phase.
Claims13
A cutting tool insert comprising a cemented carbide body and a coating, the body having a composition comprising 7.9-8.6 wt % Co, 0.5-2.1 wt % of a total amount of cubic carbides of the metals Ta and Nb, the ratio of the weight concentrations of Ta to Nb is 1.0-12.0, and balance WC, with a mean intercept length of 0.4-0.9 μm, and the binder phase being alloyed with W corresponding to an S-value of 0.81-0.95, and said coating comprises
- a first, innermost layer of TiCxNyOz with 0.7≦x+y+z≦1, with equiaxed grains and a total thickness <1 μm,
- a second layer of TiCxNyOz with 0.7≦x+y+z≦1, with a thickness of 0.5-7 μm with columnar grains,
- at least one layer of Al2O3 primarily composed of the κ-phase and having a thickness of 0.2-5 μm.
A method of making a cutting tool insert, the method comprising forming a cemented carbide body with a composition comprising 7.9-8.6 wt % Co, 0.5-2.1 wt % of a total amount of cubic carbides of the metals Ta and Nb, the ratio of the weight concentrations of Ta to Nb of 1.0-12.0, and balance WC with a mean intercept length in the range 0.4-0.9 μm, and the binder phase being alloyed with W corresponding to an S-value of 0.81-0.95, and applying a coating to the body, the coating comprising
- a first, innermost layer of TiCxNyOz with 0.7≦x+y+z≦1, with equiaxed grains and a total thickness <1 μm,
- a second layer of TiCxNyOz with 0.7≦x+y+z≦1, with a thickness of 0.5-7 μm, with columnar grains,
- at least one layer of Al2O3 primarily composed of the κ-phase and having a thickness of 0.2-5 μm.
Dependencies are inferred from the claim text.