SURFACE-COATED CUTTING TOOL WITH RIGID COATING LAYER EXHIBITING EXCELLENT CHIPPING RESISTANCE

• Main Authors: TATSUOKA, Sho, YAMAGUCHI, Kenji, SATO, Kenichi, YANAGISAWA, Kousuke
• Format: Patent
• Language: English; French; German
• Published: 11.04.2018
• 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

Provided is a coated tool in which a hard coating layer has excellent chipping resistance and fracture resistance during high-speed intermittent cutting work and exhibits excellent wear resistance during long-term use. The hard coating layer includes at least a layer of a complex nitride or complex carbonitride expressed by a composition formula: (Ti 1-x Al x ) (C y N 1-y ), a periodic concentration variation is present in crystal grains of a complex nitride or complex carbonitride having a NaCl type face-centered cubic structure in the layer, a direction of the periodic concentration variation includes at least a direction at an angle of 30 degrees or less with respect to a plane parallel to a surface of a tool body, the layer preferably has a columnar structure, an area ratio of a periodic concentration variation of Ti and Al present is 40% by area or more, a period of the concentration variation is 1 to 10 nm, a difference between an average of local maximums and an average of local minimums of a periodically varying amount x of Al is 0.01 to 0.1, fine crystal grains having a hexagonal structure with an average grain size of 0.01 to 0.3 µm are present at grain boundaries between the crystal grains in a ratio of 5% by area or less.