US 11,998,992 B2
Surface coated cutting tool having hard coating layer exhibiting excellent chipping resistance
Takuya Ishigaki, Tsukuba (JP); Kousuke Yanagisawa, Naka (JP); Hiroki Nakamura, Joso (JP); and Hisashi Honma, Naka (JP)
Assigned to MITSUBISHI MATERIALS CORPORATION, Tokyo (JP)
Appl. No. 17/279,429
Filed by MITSUBISHI MATERIALS CORPORATION, Tokyo (JP)
PCT Filed Sep. 27, 2019, PCT No. PCT/JP2019/038092
§ 371(c)(1), (2) Date Mar. 24, 2021,
PCT Pub. No. WO2020/067402, PCT Pub. Date Apr. 2, 2020.
Claims priority of application No. 2018-186044 (JP), filed on Sep. 28, 2018; and application No. 2019-146495 (JP), filed on Aug. 8, 2019.
Prior Publication US 2021/0402486 A1, Dec. 30, 2021
Int. Cl. B23B 27/14 (2006.01); B23C 5/16 (2006.01); C23C 16/30 (2006.01); C23C 16/34 (2006.01); C23C 16/36 (2006.01); C23C 16/40 (2006.01); C23C 30/00 (2006.01)
CPC B23B 27/14 (2013.01) [B23C 5/16 (2013.01); C23C 16/308 (2013.01); C23C 16/34 (2013.01); C23C 16/36 (2013.01); C23C 16/403 (2013.01); C23C 30/005 (2013.01); B23B 2224/28 (2013.01); B23B 2224/32 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A surface coated cutting tool comprising:
a tool body; and
a hard coating layer provided on a surface of the tool body, wherein
(a) the hard coating layer includes at least a complex nitride layer or a complex carbonitride layer of Ti and Al having an average layer thickness of 2.0 to 20.0 μm,
(b) when the complex nitride layer or the complex carbonitride layer is represented by a composition formula: (Ti(1-x)Alx)(CyN(i-y)), an average content ratio xavg of Al with respect to a total amount of Ti and Al and an average content ratio yavg of C with respect to a total amount of C and N (where, each of xavg and yavg is an atomic ratio) each satisfy 0.60≤xavg≤0.95 and 0.00≤yavg≤0.05,
(c) when observing a vertical cross section of each of the complex nitride layer or the complex carbonitride layer, an area ratio occupied by crystal grains having an NaCl-type face-centered cubic structure of a complex nitride or a complex carbonitride satisfies 90 area % or more,
(d) when the complex nitride layer or the complex carbonitride layer is bisected into an upper layer side and a lower layer side in a layer thickness direction, in a region on the upper layer side, in a case where a crystal grain size d of each of the crystal grains having the NaCl-type face-centered cubic structure is obtained, crystal grains having the crystal grain size d of 0.01 μm<d≤0.20 μm exist in an area ratio of 10 to 40 area % with respect to an entire area of the complex nitride layer or the complex carbonitride layer in the region on the upper layer side, and
(e) in the region on the bisected upper layer side, an average value L(dsum) of a maximum length L in a direction parallel to the surface of the tool body in each region in which the crystal grains having the NaCl-type face-centered cubic structure and each crystal grain size d of 0.01 μm<d≤0.20 μm are adjacent and connected to each other satisfies L(dsum)≤5.0 μm.