Cutting insert and method for production thereof

Patent metadata

Field	Value
Publication number	US-9238267-B2
Application number	US-201214240146-A
Country	US
Kind code	B2
Filing date	Sep 17, 2012
Priority date	Sep 16, 2011
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

Cutting insert made of hard metal, cermet or ceramic substrate body with multi-layer coating applied thereto by CVD methods. The coating has a total thickness of 5 to 40 μm and, starting from the substrate surface, has one or more hard material layers, an alpha aluminum oxide (α-Al 2 O 3 ) layer of a layer thickness of 1 to 20 μm and optionally at least portion-wise over the α-Al 2 O 3 layer one or more further hard material layers as decorative or wear recognition layers. The α-Al 2 O 3 layer has a crystallographic preferential orientation characterized by a texture coefficient TC (0 0 12)≧5 for the (0 0 12) growth direction.
The α-Al 2 O 3 layer has an inherent stress in the region of 0 to +300 MPas, and the substrate within a region of 0 to 10 μm from the substrate surface has an inherent stress minimum in the region of −2000 to −400 MPas.

First claim

The invention claimed is:

1. A cutting insert:
a hard metal, cermet or ceramic substrate body; and
a multi-layer coating which is applied thereto by means of CVD methods of a total thickness of 5 to 40 μm and which starting from a surface of the substrate body has one or more hard material layers, over the hard material layers an alpha aluminium oxide (α-Al 2 O 3 ) layer of a layer thickness of 1 to 20 μm and optionally at least portion-wise over the α-Al 2 O 3 layer one or more further hard material layers as decorative or wear recognition layers,
wherein the α-Al 2 O 3 layer has a crystallographic preferential orientation, characterised by a texture coefficient TC (0 0 12)≧5 for the (0 0 12) growth direction with

TC
⁡

(

0

0

12

)

=

I
⁡

(

0

0

12

)

I
0

⁡

(

0

0

12

)

⁡

[

1
n

⁢

∑

n
-
1

n

⁢

I
⁡

(
hkl
)

I
0

⁡

(
hkl
)

]

-
1

,

wherein
I(hkl) are the intensities of the diffraction reflections measured by X-ray diffraction,
I 0 (hkl) are the standard intensities of the diffraction reflections in accordance with pdf card 42-1468,
n is the number of reflections used for the calculation, and
the following reflections are used for the calculation of TC(0 0 12):
(0 1 2), (1 0 4), (1 1 0), (1 1 3), (1 1 6), (3 0 0) and (0 0 12),

wherein the α-Al 2 O 3 layer has an inherent stress in the region of 0 to +300 MPas, and
wherein the substrate within a region of 0 to 10 μm from the surface of the substrate body has an inherent stress minimum in the region of −2000 to −400 MPas.

2. A cutting insert according to claim 1 wherein the production of the cutting insert includes the substrate body being subjected to a dry or wet jet blasting treatment using a granular jet blasting agent after application of the multi-layer coating.

3. A cutting insert according to claim 1 wherein the hard material layers arranged over the surface of the substrate body and under the α-Al 2 O 3 layer and the hard material layers arranged at least portion-wise optionally over the α-Al 2 O 3 layer comprise carbides, nitrides, oxides, carbonitrides, oxynitrides, oxycarbides, oxycarbonitrides, borides, boronitrides, borocarbides, borocarbonitrides, borooxynitrides, borooxocarbides or borooxocarbonitrides of the elements of groups IVa to Vila of the periodic system and/or aluminium and/or mixed metal phases and/or phase mixtures of the afore-mentioned compounds.

4. A cutting insert according to claim 1 wherein the hard material layers arranged over the surface of the substrate body and under the α-Al 2 O 3 layer comprise TiN, TiCN and/or TiAlCNO, wherein the hard material layers respectively involve layer thicknesses in the region of 0.1 μm to 15 μm.

5. A cutting insert according to claim 1 wherein the hard material layers arranged over the substrate surface and under the α-Al 2 O 3 layer and comprising TiN, TiCN and/or TiAlCNO are together of a total layer thickness in the region of 3 μm to 16 μm.

6. A cutting insert according to claim 1 wherein the multi-layer coating starting from the surface of the substrate body has the following layer succession: TiN—TiCN—TiAlCNO-α-Al 2 O 3 , wherein optionally a TiN layer, a TiCN layer, a TiC layer or a combination thereof are provided at least portion-wise over the α-Al 2 O 3 layer.

7. A cutting insert according to claim 1 wherein, within a region from the outermost surface region to a depth of 10 μm from the outermost surface of the substrate body, the substrate body has an inherent stress minimum of at least −400 MPas, preferably at least −600 MPas.

8. A cutting insert according to claim 1 wherein the substrate body comprises hard metal, containing 4 to 12% by weight of Co, Fe and/or Ni, optionally 0.5 to 10% by weight of cubic carbides of the metals of groups IVb, Vb and VIb of the periodic system, or combinations thereof, and WC as the balance.

9. A cutting insert according to claim 1 wherein the substrate body comprises hard metal and has a surface zone which is enriched with Co binder phase in relation to a nominal overall composition of the substrate body and which is depleted of cubic carbides and which starting from the surface of the substrate body is of a thickness of 5 μm to 30 μm, wherein a content of Co in the surface zo

Assignees

• Walter Ag

Inventors

• Stiens Dirk
• Ruppi Sakari
• Fuhrmann Thomas

Classifications

• C23C16/403 Primary

  of aluminium, magnesium or beryllium · CPC title

• C23C30/005

  on hard metal substrates · CPC title

• C23C28/044

  coatings specially adapted for cutting tools or wear applications · CPC title

• C23C16/56

  After-treatment · CPC title

• Y10T428/24975

  No layer or component greater than 5 mils thick · CPC title