| 摘要 |
PURPOSE:To provide a sintered hard alloy member excellent in toughness, wear resistance, and plastic deformation resistance, which is improved in machinability in a region from finishing to semifinishing machining, by forming a surface layer having specific composition just under the hard coated layer of sintered hard alloy base material composed of iron group metals and WC etc. CONSTITUTION:On the surface of a sintered hard alloy base material consisting of 5-30% by vol. one or more iron group metals as bonding-phase-forming components, if necessary, 30% or less carbide, nitride, or carbonitride of two or more members of IVa, Va, VIa group metals, and NaCl type crystal structural component of a solid soln. composed of these two or more material described above, and WC and inevitable impurities is formed a single- or multilayer hard coating (1-20mum in thickness) comprising carbide or carbonitride, Al2O3, and a solid soln. composed of two or more of these materials. In addn., the base material surface portion (1- 50mum in thickness) just under the coating layer is composed of 80-99% by vol. carbide or carbonitride and NaCl type crystal structure component described above, 20-1% iron group metal, thereby forming a hardened surface layer having Vickers hardness 5-50% higher than that of the inner part of the base material. |
