Coated PCBN cutting inserts
AssigneeKennametal PC Inc.
InventorsEdward J. Oles, Kent L. Reiner, Alfred S. Gates, Jr., Edward T. Mohrbach
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Abstract
A cutting tool and method for machining hardened steel including a substrate of polycrystalline cubic boron nitride having one or more layers of a hard refractory coating containing aluminum. The coating may contain a titanium aluminum nitride layer applied by a physical vapor deposition (PVD). Alternatively, the coating may include a layer of aluminum oxide applied by chemical vapor deposition.
Claims35
A coated cutting tool for machining hardened steel comprising:
- a substrate comprising polycrystalline cubic boron nitride having a rake surface and a flank surface and a cutting edge for machining hardened steel having a Rockwell C hardness greater than 45;
- and
- a coating applied to said substrate by one of a PVD or CVD technique, or a combination thereof, comprising at least one layer containing Al.
A coated cutting tool for machining hardened material having a hardness value greater than about 45 Rc comprising:
- a substrate comprising polycrystalline cubic boron nitride having a rake surface with a surface roughness of no greater than about 10 microinches Ra;
- a coating of about 2-20 μm in thickness applied to said substrate by one of a PVD or CVD technique comprising at least one layer containing Al;
- and
- said coating having a Rockwell A indent adhesion strength of greater than or equal to 60 kg to said rake surface of said substrate.
A method of finish machining a hardened steel having a hardness greater than 45 Rc comprising the steps of:
- providing a coated cutting tool comprising a brazed substrate of polycrystalline cubic boron nitride brazed to a cemented carbide substrate, said brazed substrate having a coating comprising at least one layer containing Al applied thereto by one of a PVD or CVD technique or a combination thereof;
- and
- machining the hardened steel using said coating cutting tool at a depth of cut of no more than 0.050 inch.
A coated cutting tool for machining hardened steel comprising:
- a composite insert comprising a body made from a WC containing material having a substrate of a polycrystalline boron nitride material brazed therein and defining a cutting edge on said substrate;
- said body having a rake surface and a flank surface bordering said substrate, wherein said rake surface has a surface roughness in an uncoated condition of no more than about 10 microinches Ra;
- a coating applied to said substrate by a PVD technique in a thickness of about 2-5 μm comprising at least one layer containing Al;
- and
- said coating having a Rockwell A indent adhesion strength of greater than or equal to 60 kg to said rake surface of said substrate.
Dependencies are inferred from the claim text.