Patent ID: 7762747

Claim:
A titanium carbonitride-based cermet insert containing a titanium carbonitride-based cermet having a microstructure comprising 75 to 90 area % of a hard phase and the balance as a binding phase, wherein the hard phase comprises: (1) a first hard phase having a core-having structure in which a core portion includes a titanium carbonitride phase, and a peripheral portion includes a complex carbonitride phase having Ti, W, and one kind or two kinds of Ta and Nb (to be referred to as (Ti,W,Ta/Nb)CN); (2) a second hard phase having a core-having structure in which both a core portion and a peripheral portion include (Ti,W,Ta/Nb)CN phases; and (3) a third hard phase having a single phase structure including a titanium carbonitride phase, and the binding phase contains a W—Co—Ni-based alloy having a composition comprising, as a ratio in the binding phase and by mass %, at least: 18 to 33 mass % of Co; 20 to 35 mass % of Ni; 5 mass % or less of Ti, and one kind or two kinds of Ta and Nb, the total amount thereof; and 40 to 60 mass % of W.