| 摘要 |
PROBLEM TO BE SOLVED: To prevent break and dipping by using a specific throwaway tip. SOLUTION: A tip is constituted of a carbonitride titanium-based cermet wherein a hard phase occupies 75-95 area %, and the remainder is composed of a joining phase and an inevitable impurity, the hard phase has core structure where core and peripheral parts are practically composed of a composite carbonitride of Ti and M (M is one or two or more kinds of Ta, Nb, V, W, and Zr) and the joining phase is composed of a Co-Ni-W based alloy containing 15-35 wt.% W, 10-50 wt.% Ni, 20-70 wt.% Co in the joining phase (W+Ni+Co=90 wt.% or more). An angle between a rake face and a flank in the cutting edge ridge part of this tip is set 65-75 deg., and this tip is fitted to a ringlike tool main body at an axial rake angle of 15-30 deg. (a tilted angle to the axial line of the tool main body).
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