| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool improved in the quality of a cut surfce in cutting low carbon non-lead free-cutting steel and improved in quality exceeding a level achieved in the conventional low carbon free-cutting steel. SOLUTION: In this cutting tool, the cutting edge roundness of one or both of a main cutting edge and a sub-cutting edge has a radius of 50μm or less, the partial or whole surface layer of the surface coming into contact with a material to be cut is coated with a hard film. The hard film contains N: 40 to 60% in atom % and Ti: 40 to 60% in atom %. The hard film further contains 40% or less one or two kinds of Al and Zr in atom %. When the cutting tool is used in cutting low-carbon non-lead free-cutting steel, since the steel is hard to cohere to the cutting edge, a built-up edge is hardly formed, and the cutting edge roundness has a radius of 50μm or less, whereby good surface roughness not obtained in the past can be achieved and the breakage of the cutting edge is hardly caused to obtain an extremely favorable tool life. COPYRIGHT: (C)2006,JPO&NCIPI
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