Surface-coated cutting tool and method of producing the same

Patent metadata

Field	Value
Publication number	US-10100403-B2
Application number	US-201615311429-A
Country	US
Kind code	B2
Filing date	Jun 7, 2016
Priority date	Apr 8, 2016
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A surface-coated cutting tool includes a base material and a coating formed on a surface of the base material. The coating includes a first hard coating layer including crystal grains having a sodium chloride-type crystal structure. The crystal grain has a layered structure in which a first layer composed of nitride or carbonitride of Al x Ti 1−x and a second layer composed of nitride or carbonitride of Al y Ti 1−y are stacked alternately into one or more layers. The first layer each has an atomic ratio x of Al varying in a range of 0.76 or more to less than 1. The second layer each has an atomic ratio y of Al varying in a range of 0.45 or more to less than 0.76. The largest value of difference between the atomic ratio x and the atomic ratio y is 0.05≤x−y≤0.5.

First claim

The invention claimed is:

1. A surface-coated cutting tool comprising: a base material; and a coating formed on a surface of the base material, wherein
said coating includes a first hard coating layer including crystal grains having a sodium chloride-type crystal structure,
said crystal grain has a layered structure in which a first layer composed of nitride or carbonitride of Al x Ti 1−x and a second layer composed of nitride or carbonitride of Al y Ti 1−x are stacked alternately into one or more layers,
said first layer each has an atomic ratio x of Al varying in a range of 0.76 or more to less than 1,
said second layer each has an atomic ratio y of Al varying in a range of 0.45 or more to less than 0.76,
a largest value of difference between said atomic ratio x and said atomic ratio y is 0.05≤x−y≤0.5,
said first layer and said second layer adjacent to each other have a total thickness of 3 to 30 nm,
in said crystal grains, when crystal orientation of each said crystal grain is analyzed in a cross section parallel to a normal direction of the surface of said base material using an electron backscatter diffraction system to determine an angle of intersection between a normal to a (200) plane that is a crystal plane of the crystal grain and a normal to the surface of said base material, said crystal grains having said angle of intersection of 0 to 45 degrees are classified in units of 0 degree to 5 degrees to form nine groups, and a frequency that is the sum of areas of said crystal grains included in each group is calculated, a total of said frequencies of four groups including said crystal grains having said angle of intersection of 0 to 20 degrees is 50% or more and 100% or less of a total of said frequencies of all groups, and
a total of said frequencies of two groups including said crystal grains having said angle of intersection of 10 to 20 degrees is 30% or more and 100% or less of a total of said frequencies of said all groups.

2. The surface-coated cutting tool according to claim 1 ,
wherein
said coating includes a second hard coating layer between said base material and said first hard coating layer, and
said second hard coating layer has a thickness of 0.01 to 0.5 μm.

3. The surface-coated cutting tool according to claim 1 , wherein said first hard coating layer has a thickness of 1 to 15 μm.

4. The surface-coated cutting tool according to claim 1 , wherein said first hard coating layer has an indentation hardness by nanoindentation of 28 GPa or more and 38 GPa or less.

5. The surface-coated cutting tool according to claim 1 , wherein said first hard coating layer has an absolute value of compression residual stress of 0.5 GPa or more and 5.0 GPa or less.

6. A method of producing the surface-coated cutting tool of claim 1 , the method comprising:
a first step of preparing said base material; and
a second step of forming said coating including said first hard coating layer by chemical vapor deposition.

7. The method of producing the surface-coated cutting tool according to claim 6 , wherein said second step includes the step of growing said crystal grains while varying a flow rate of one or both of AlCl 3 gas and TiCl 4 gas.

Assignees

• Sumitomo Electric Hardmetal Corp

Inventors

• Paseuth Anongsack
• Imamura Shinya
• Ono Satoshi
• Kanaoka Hideaki

Classifications

• B23B2222/28

  Details of hard metal, i.e. cemented carbide · CPC title

• C23C30/005

  on hard metal substrates · CPC title

• B23B2224/00

  Materials of tools or workpieces composed of a compound including a metal · CPC title

• C23C28/044

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

• B23B2222/16

  Cermet · CPC title