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AssigneeSandvik Intellectual Property AB
InventorsLeif Akesson, Kenneth Westergren
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The present invention relates to coated cutting tool inserts particularly useful for heavy roughing turning operations of very large steel components, such as drive shafts for ships and shafts for wind power plants. The inserts are large with an iC, inscribed circle diameter, of greater than or equal to about 19 mm and a thickness of greater than or equal to about 6 mm with a composition of from about 5 to about 10 wt-% Co, from about 5 to about 12 wt-% cubic carbides or carbonitrides of the metals Ti, Ta and/or Nb, and balance WC with a stratified binder phase enriched surface zone from about 15 to about 40 μm thick. The inserts have an edge rounding before coating of 35-95 μm. The coating comprises a first, innermost layer of TiCxNyOz and a total thickness from about 0.1 to about 1.5 μm, a second layer of TiCxNy with a thickness of from about 4.5 to about 9.5 μm with columnar grains, a third layer of TiCxNyOz with a thickness of from about 0.3 to about 1.5 μm, a fourth layer of a smooth α-Al2O3 with a thickness of from about 4.5 to about 9.5 μm and, a from about 0.1 to about 2 μm thick colored top layer, preferably TiN or ZrN, on the clearance sides. The invention also relates to the method of making such inserts and the use thereof for heavy roughing turning operations of very large steel components.
Coated cutting tool insert comprising a cemented carbide insert body with a stratified binder phase enriched surface zone and a coating wherein
Method of making a coated cutting tool insert comprising a cemented carbide insert body with a stratified binder phase enriched surface zone and a coating comprising providing a cemented carbide insert body with an inscribed circle diameter of greater than or equal to about 19 mm, and a thickness of greater than or equal to about 6 mm, with a carbon content corresponding to a C-porosity in the inner central part of the cemented carbide insert body of from about C06 to about C08, and a Hc-value of from about 9.0 to about 13.5, the stratified binder phase enriched surface zone is from about 15 to about 45 μm thick and the binder phase content of the binder phase enriched surface zone has a maximum of from about 1.5 to about 4 times the nominal binder phase content made by sintering a presintered or compacted body with, for formation of stratified layers, an optimum amount of carbon in an inert atmosphere or in vacuum, for about 15 to about 180 min at from about 1380 to about 1520° C., followed by slow cooling, from about 20 to about 100° C./h, through the solidification region, from about 1300 to about 1220° C.
Dependencies are inferred from the claim text.