SURFACE COATED CUTTING TOOL IN WHICH HARD COATING LAYER DEMONSTRATES EXCELLENT WEAR RESISTANCE IN HIGH SPEED CUTTING PROCESS OF DUCTILE CAST IRON OR THE LIKE

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool in which a hard coating layer demonstrates excellent wear resistance in high speed cutting process of a ductile cast iron or the like.;SOLUTION: A surface coated cutting tool is provided in which, a surface of a tool base body, a lower layer containing a Ti compound layer containing a reformed TiCN layer having at least longitudinal growth crystal system and an upper layer consisting of a reformed Al₂O₃ layer of columnar structure are coated. A ratio value GBLa/Ta of length GBLa(μm) of grain boundary measured about the reformed TiCN layer and layer thickness Ta(μm) of the reformed TiCN layer that is measured is 275-520. A ratio value GBLb/Tb of length GBLb(μm) of grain boundary measured about the reformed Al₂O₃ layer and layer thickness Tb(μm) of the reformed Al₂O₃ layer that is measured is 350-520. Relating to a cutting surface part in a width range of at least 0.5 mm from a blade ridge part consisting of an intersection between a cutting surface and an escape surface, if surface roughness is measured using a laser microscope, arithmetic average roughness Ra is 0.2 μm or less, arithmetical average inclination angle RΔa is 10° or less, root-mean-square inclination angle RΔq is 15° or less, and tensile residual stress of the reformed Al₂O₃ layer by residual stress measurement using XRD is 150 MPa.;COPYRIGHT: (C)2015,JPO&INPIT