CEMENTED CARBIDE TOOL AND MANUFACTURING METHOD OF THE SAME

• Main Authors: KANDA OSAMU, MATSUMOTO TAKUYA
• Format: Patent
• Language: English; Japanese
• Published: 07.09.2015
• Subjects: BORING; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; TRANSPORTING; TURNING

PROBLEM TO BE SOLVED: To provide a cemented carbide tool and a manufacturing method of the same provided with a protective film which is hardly scraped and is hardly peeled.SOLUTION: A cemented carbide tool 1a includes a base material 2 formed of hard metal, and a protective film 3a which is formed on the base material 2, has a thickness of 3.0 μm or more, and is formed of metal nitride. The protective film 3a includes a metal nitride film 31a, a metal nitride film 32a, and a metal nitride film 33a. The metal nitride film 31a is formed on the base material 2, has a thickness of 0.5-3.0 μm, and has a linear thermal expansion coefficient larger than a linear thermal expansion coefficient of the base material 2. The metal nitride film 32a is formed on the metal nitride film 31a, has a thickness of 0.5-3.0 μm, and has a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient of the metal nitride film 31a. The metal nitride film 33a is formed on the metal nitride film 32a, has a thickness of 0.5-3.0 μm, and has a linear thermal expansion coefficient larger than the linear thermal expansion coefficient of the metal nitride film 32a. 【課題】削れにくく、かつ、剥がれにくい保護膜を備える超硬工具およびその製造方法を提供する。【解決手段】超硬工具１ａは、超硬合金からなる基材２と、基材２上に形成され、３．０μｍ以上の厚さを有し、金属窒化物からなる保護膜３ａと、を備える。保護膜３ａは、金属窒化膜３１ａと、金属窒化膜３２ａと、金属窒化膜３３ａとを含む。金属窒化膜３１ａは、基材２上に形成され、０．５〜３．０μｍの厚さを有し、基材２の線熱膨張係数よりも大きい線熱膨張係数を有する。金属窒化膜３２ａは、金属窒化膜３１ａ上に形成され、０．５〜３．０μｍの厚さを有し、金属窒化膜３１ａの線熱膨張係数よりも小さい線熱膨張係数を有する。金属窒化膜３３ａは、金属窒化膜３２ａ上に形成され、０．５〜３．０μｍの厚さを有し、金属窒化膜３２ａの線熱膨張係数よりも大きい線熱膨張係数を有する。【選択図】図１