Ngk Spark Plug Company, Limited

Mitsubishi Materials Corporation

Hiroaki Takashima

Kei Takahashi

Atsushi Komura

Toshiyuki Taniuchi

Masafumi Fukumura

Tomoaki Shindo

A cermet insert having a structure composed of a hard phase and a binding phase and, as a sintered body composition, containing Ti, Nb and/or Ta, and W in a total amount of Ti in terms of carbonitride, Nb and/or Ta in terms of carbide and W in terms of carbide of 70 to 95 wt. % of an entirety of the microstructure, and containing W in terms of carbide in an amount of 15 to 35 wt. % of the entirety of the microstructure, the sintered body composition further containing Co and/or Ni. The hard phase has one or two or more of the phases: (1) a first hard phase of a core-having structure whose core portion contains a titanium carbonitride phase and a peripheral portion containing a (Ti, W, Ta/Nb)CN phase, (2) a second hard phase of a core-having structure whose core portion and peripheral portion both contain a (Ti, W, Ta/Nb)CN phase, and (3) a third hard phase of single-phase structure including a titanium cabonitride phase. Moreover, the titanium carbonitride phase includes a W-rich phase unevenly distributed in the titanium carbonitride phase.

Cermet insert and cutting tool

One aspect of this titanium carbonitride-based cermet insert has a microstructure including 75 to 90 area % of a hard phase and the balance as a binding phase, wherein the hard phase includes a first hard phase in which a core-having structure includes a TiCN phase and a peripheral portion includes a (Ti,W,Ta/Nb)CN phase, a second hard phase including a (Ti,W,Ta/Nb)CN phase, and a third hard phase including a TiCN phase, and the binding phase contains 18 to 33% of Co, 20 to 35% of Ni, 5% or less of Ti and Ta and/or Nb, and 40 to 60 mass % of W. In another aspect of this cermet insert, a total of an amount of Ti converted as carbonitride, an amount of Ta and/or Nb converted as carbide, and an amount of W converted as carbide is 70 to 95 mass %, an amount of W converted as carbide is 20 to 35 mass %, and Co and Ni are 5 to 30 mass %, this cermet insert has a microstructure including a hard phase containing (Ti,W,Ta/Nb)CN and a binding phase containing, as main components thereof, W and Co and/or Ni, and 40 to 65 mass % of the W is contained in the hard phase. This cutting tool includes a holder and the cermet insert described above held and fixed by the holder.

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Komaki, Japan

Hiroaki Takashima