Cutting tool

Patent metadata

Field	Value
Publication number	US-11167355-B2
Application number	US-201916637038-A
Country	US
Kind code	B2
Filing date	Jul 5, 2019
Priority date	Oct 15, 2018
Publication date	Nov 9, 2021
Grant date	Nov 9, 2021

Abstract

A cutting tool includes: a substrate including a rake face; and a coating film that coats the rake face, wherein the coating film includes an α-Al2O3 layer disposed on the substrate, the α-Al2O3 layer includes crystal grains of α-Al2O3, an area ratio of crystal grains oriented in (001) among the crystal grains is 50% to 90% in the α-Al2O3 layer at the rake face, and a film residual stress AA determined based on a crystal plane interval of a (001) plane of the α-Al2O3 layer at the rake face is more than 0 MPa and less than or equal to 2000 MPa, and a film residual stress BA determined based on a crystal plane interval of a (110) plane of the α-Al2O3 layer at the rake face is more than or equal to −1000 MPa and less than 0 MPa.

First claim

The invention claimed is:

1. A cutting tool comprising: a substrate including a rake face; and a coating film that coats the rake face, wherein
the coating film includes an α-Al 2 O 3 layer disposed on the substrate,
the α-Al 2 O 3 layer includes crystal grains of α-Al 2 O 3 ,
an area ratio of crystal grains oriented in (001) among the crystal grains is more than 50% and less than 90% in the α-Al 2 O 3 layer at the rake face, and
in a residual stress measurement performed in accordance with a 2θ-sin 2 ψ method using X rays,
a film residual stress A A determined based on a crystal plane interval of a (001) plane of the α-Al 2 O 3 layer at the rake face is more than 0 MPa and less than or equal to 2000 MPa, and
a film residual stress B A determined based on a crystal plane interval of a (110) plane of the α-Al 2 O 3 layer at the rake face is more than or equal to −1000 MPa and less than 0 MPa.

2. The cutting tool according to claim 1 , wherein
the α-Al 2 O 3 layer has a thickness of more than or equal to 1 μm and less than or equal to 20 μm,
in a residual stress measurement performed in accordance with a constant penetration depth method using X rays at a region r 1 interposed between a virtual plane D 1 and a virtual plane D 2 , the virtual plane D 1 being located at a distance d 10 from a surface of the α-Al 2 O 3 layer opposite to the substrate toward the substrate side, the distance d 10 being 10% of the thickness of the α-Al 2 O 3 layer, the virtual plane D 2 being located at a distance d 40 from the surface of the α-Al 2 O 3 layer opposite to the substrate toward the substrate side, the distance d 40 being 40% of the thickness of the α-Al 2 O 3 layer,
a residual stress A determined based on the crystal plane interval of the (001) plane of the α-Al 2 O 3 layer at the rake face is more than or equal to −200 MPa and less than or equal to 2000 MPa, and
a residual stress B determined based on the crystal plane interval of the (110) plane of the α-Al 2 O 3 layer at the rake face is more than or equal to −1500 MPa and less than or equal to 700 MPa, and

a relational expression of A>B is satisfied.

3. The cutting tool according to claim 2 , wherein
a stress distribution of the residual stress A has
a first a region in which the residual stress A is decreased continuously from the surface of the α-Al 2 O 3 layer opposite to the substrate toward the substrate side, and
a second a region which is located at the substrate side relative to the first a region and in which the residual stress A is increased continuously from the surface opposite to the substrate toward the substrate side, and

the first a region and the second a region are continuous to each other via a minimum point of the residual stress A.

4. The cutting tool according to claim 2 , wherein
a stress distribution of the residual stress B has
a first b region in which the residual stress B is decreased continuously from the surface of the α-Al 2 O 3 layer opposite to the substrate toward the substrate side, and
a second b region which is located at the substrate side relative to the first b region and in which the residual stress B is increased continuously from the surface opposite to the substrate toward the substrate side, and

the first b region and the second b region are continuous to each other via a minimum point of the residual stress B.

5. The cutting tool according to claim 1 , wherein
the coating film further includes one or more intermediate layers disposed between the substrate and the α-Al 2 O 3 layer, and
each of the intermediate layers includes a compound that is composed of at least one element selected from a group consisting of a group 4 element, a group 5 element, a group 6 element in a periodic table, Al and Si, and at least one element selected from a group consisting of C, N, B, and O.

Assignees

• Sumitomo Electric Hardmetal Corp

Inventors

• Okuno Susumu
• Imamura Shinya
• Ono Satoshi
• Paseuth Anongsack

Classifications

• C23C28/3455

  with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer · CPC title

• C23C28/044

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

• B23C5/16

  characterised by physical features other than shape · CPC title

• B23B51/00

  Tools for drilling machines · CPC title

• B23B27/14 Primary

  Cutting tools of which the bits or tips {or cutting inserts} are of special material · CPC title