SURFACE-COATED CUTTING TOOL HAVING EXCELLENT DEFECT RESISTANCE

• Main Author: TATSUOKA SHO
• Format: Patent
• Language: English; Japanese
• Published: 25.04.2019
• Subjects: BORING; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; MILLING; PERFORMING OPERATIONS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING; TURNING

To provide a surface-coated cutting tool in which a hard coating layer has excellent chipping resistance, defect resistance, and oxidation resistance in a high-speed intermittent heavy steel cutting work such that an impulsive high load acts on a cutting blade.SOLUTION: A hard coating layer is provided on a surface of a substrate comprising a tungsten carbide-based hard metal, a carbonitride titanium-based cermet, and a cubic boron nitride-based superhigh pressure sintered body. The hard coating layer comprises a layer of a composite nitride of Al and Ti or a composite carbonitride, and includes a composite part comprising a matrix part which has a triangular shape in a plane perpendicular to a layer thickness direction, and a peripheral part in which an oxide or an oxynitride containing at least one element of Al and Zr is arranged on the matrix part. In the composite part, an area ratio of an equivalent crystal face, which is represented by {111} face, in a crystal grain having a NaCl type face-centered cubic structure is 35 area % or more in total when performing texture observation from a front side of the layer of composite nitride or composite carbonitride by electron beam back scattering diffraction method (EBSD method).SELECTED DRAWING: Figure 1 【課題】切刃に対し衝撃的な高負荷が作用する鋼の高速断続重切削加工において、硬質被覆層がすぐれた耐チッピング性、耐欠損性、耐酸化性を有する表面被覆工具を提供する。【解決手段】炭化タングステン基超硬合金、炭窒化チタン基サーメット、立方晶窒化ホウ素基超高圧焼結体からなる基体表面に硬質被覆層が設けられ、前記硬質被覆層は、ＡｌとＴｉの複合窒化物または複合炭窒化物層よりなり、層厚方向に垂直な面内において三角形状を有するマトリックス部と、前記マトリックス部にＡｌとＺｒの少なくとも一つの元素を含む酸化物または酸窒化物が配置されてなる周辺部とからなる複合部を含み、前記複合部は、複合窒化物または複合炭窒化物層の表面側から電子線後方散乱回折法（ＥＢＳＤ法）にて組織観察を行った際に、前記ＮａＣｌ型の面心立方構造を有する結晶粒において、{１１１}面で表される等価な結晶面の面積率が、全体の３５面積％以上である表面被覆切削工具。【選択図】図１