| 摘要 |
PURPOSE: To provide a surface coating cemented carbide alloyed cutting tool that combines both of surpassing wear resistance and anti-crackedness, aside from being high hardness and high strength. CONSTITUTION: In a cutting tool is made up of installing those of 4a, 5a, 6a family metals of a periodic table and a carbide, a nitride, an oxide, a borite of one type or more than two types of metal elects selected from an A1 group and a film compound of one type single layer or mare than two types of plural layers of a compound consisting of these metal elements on the surface of a base body made up of a binder phase and inevitable impurities consisting of one type or more than two types among hard phase, ferrous metals using tungsten carbide as the main ingredients, each maximum grain size of the hard phase is less than 2μm. In this constitution, a volumetric percentage of each grain of less than 1μm in grainsize in the hard phase should be such one as being increased toward the surface from the inner part.
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