US 12,350,742 B2
Surface-coated cutting tool
Hiroki Nakamura, Joso (JP); Takuya Ishigaki, Joso (JP); Kousuke Yanagisawa, Naka-gun (JP); and Hisashi Honma, Tokyo (JP)
Assigned to MITSUBISHI MATERIALS CORPORATION, Tokyo (JP)
Appl. No. 17/794,489
Filed by MITSUBISHI MATERIALS CORPORATION, Tokyo (JP)
PCT Filed Feb. 3, 2021, PCT No. PCT/JP2021/003917
§ 371(c)(1), (2) Date Jul. 21, 2022,
PCT Pub. No. WO2021/157609, PCT Pub. Date Aug. 12, 2021.
Claims priority of application No. 2020-016659 (JP), filed on Feb. 3, 2020.
Prior Publication US 2023/0109216 A1, Apr. 6, 2023
Int. Cl. B23B 27/14 (2006.01); C23C 16/36 (2006.01)
CPC B23B 27/148 (2013.01) [C23C 16/36 (2013.01); B23B 2228/105 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A surface-coated cutting tool comprising:
a tool body; and
a hard coating layer that includes a Ti—Al complex carbonitride or nitride layer on a surface of the tool body, wherein
(a) a ratio of crystal grains of Ti—Al complex carbonitride or nitride, which has a NaCl type face-centered cubic structure, in the Ti—Al complex carbonitride or nitride layer is 80 area % or more,
(b) in the Ti—Al complex carbonitride or nitride layer, xavg and yavg satisfy 0.60≤xavg≤0.90 and 0.000≤yavg≤0.050, respectively, a composition of the Ti—Al complex carbonitride or nitride layer being represented by a composition formula of (Ti1-xAlx) (CyN1-y), the xavg being an average of x that is an Al content in a total content of Al and Ti, the yavg being an average of y that is a C content in a total content of C and N, and the x, the y, the xavg and yavg being atomic ratios,
(c) the crystal grains which have the NaCl type face-centered cubic structure include crystal grains in which the x repeatedly increases and decreases in a direction perpendicular to the surface of the tool body,
(d) the crystal grains in which the x repeatedly increases and decreases include 10 to 40 area % of crystal grains G1 including a region having a first distance davg1 in which an average distance of the repeated increase and decrease is 40 to 160 nm, and
(e) the crystal grains in which the x repeatedly increases and decreases include 60 area % or more of crystal grains Gs including a region having a second distance davgs in which an average distance of the repeated increase and decrease is 1 to 7 nm.