(19)
(11)EP 3 587 609 A8

(12)CORRECTED EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(15)Correction information:
Corrected version no 1 (W1 A1)

(48)Corrigendum issued on:
18.03.2020 Bulletin 2020/12

(43)Date of publication:
01.01.2020 Bulletin 2020/01

(21)Application number: 19769977.0

(22)Date of filing:  29.01.2019
(51)International Patent Classification (IPC): 
C22C 29/08(2006.01)
B23B 51/00(2006.01)
C22C 1/05(2006.01)
B23B 27/14(2006.01)
B23C 5/16(2006.01)
(86)International application number:
PCT/JP2019/002981
(87)International publication number:
WO 2019/207876 (31.10.2019 Gazette  2019/44)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(30)Priority: 26.04.2018 JP 2018085641

(71)Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
Osaka-shi, Osaka 541-0041 (JP)

(72)Inventors:
  • FUKAE, Kosuke
    Osaka-shi Osaka 5410041 (JP)
  • GOTOU, Hiroaki
    Osaka-shi Osaka 5410041 (JP)
  • MICHIUCHI, Masato
    Osaka-shi Osaka 5410041 (JP)
  • TSUDA, Keiichi
    Osaka-shi Osaka 5410041 (JP)

(74)Representative: Boult Wade Tennant LLP 
Salisbury Square House 8 Salisbury Square
London EC4Y 8AP
London EC4Y 8AP (GB)

  


(54)CEMENTED CARBIDE, CUTTING TOOL CONTAINING SAME, AND PRODUCTION METHOD FOR CEMENTED CARBIDE


(57) Cemented carbide contains first hard-phase particles containing WC, second hard-phase particles which contain carbonitride containing at least Ti and Nb, and a metallic binder phase containing an iron-group element. The second hard-phase particle includes a granular core portion and a peripheral portion which covers at least a part of the core portion. The core portion contains composite carbonitride expressed as Ti1-X-YNbXWYC1-ZNZ, where X is not smaller than 0.1 and not greater than 0.2, Y is not smaller than 0 and not greater than 0.05, and Z is not smaller than 0.3 and not greater than 0.6. The peripheral portion is different in composition from the core portion. The cemented carbide has an absolute value of a difference not greater than 10, between a ratio (%) of an area occupied by the second hard-phase particles at a surface thereof and a ratio (%) of an area occupied by the second hard-phase particles in a region extending from the surface by 0.5 mm in a direction of depth.