Method for increasing compression stress or reducing internal tension stress of a CVD, PCVD or PVD layer and cutting insert for machining
AssigneeWidia GmbH
InventorsHartmut Westphal, Volkmar Sottke
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Abstract
A method of increasing the compressive stress or of reducing the tensile residual stress of a CVD layer, a PCVD layer or PVD layer and a cutting insert for machining. The invention relates to a method of increasing the compressive residual stress or of reducing the tensile residual stress of a hard material outer layer or a hard material outermost layer in which the coated substrate after coating is subjected to a dry blast treatment using a granular blast agent that, according to the invention, has a maximum diameter of 150 μm.
Claims10
A method of increasing the compressive residual stress or of reducing the tensile residual stress of an outer hard material layer or an outermost hard material layer, comprising the steps of:
- applying at least one hard material layer as said outer or outermost layer by means of CVD, PCVD or PVD to a hard metal substrate body, a cermet substrate body or a ceramic substrate body;
- subjecting the coated substrate body after coating to a dry blast treatment using spray-formed hard metal granulate as a granular blast agent in the form of round grains with a maximum diameter of 150 μm.
A cutting insert for machining comprised of a hard metal substrate body, a cermet substrate body or a ceramic substrate body with a single layer or multilayer coating of carbides, nitrides, carbonitrides, oxycarbonitrides and/or borides of the elements of groups IVa to VIa of the periodic system, boron-containing hard material compounds and/or oxidic compounds of aluminum and/or zirconium which are applied by a PCVD process or a CVD process wherein the compressive residual stress in the outer or outermost layer is 4.5 to 10 Gpa provided by training a spray formed hard metal granulate composed of round grains of a particle size of 5 to 50 μm in a compressed air stream at a pressure of 6×105 Pa to 7×105 Pa perpendicularly against said coating.
Dependencies are inferred from the claim text.