Patent ID: 7320716

Claim:
A method for surface toughening of a ceramics sintered material cutting tool comprising, plastic working said ceramics sintered material cutting tool with an abrasive composed of fine particles, said fine particles having a convexly curved surface and an average particle size of 0.1 μm to 200 μm and a Vickers hardness (HV) ranging from 500 to a value which is the hardness of said sintered material cutting tool plus 50, whereby a uniformly distributed linear dislocation structure is formed in subsurface regions of the ceramics sintered material cutting tool, said plastic working being carried out by shot blasting said sintered material cutting tool with said abrasive particles at a pressure of 0.1 to 0.5 MPa, a shot blasting speed of 20 m/sec to 250 m/sec, a shot blasting amount of 50 g/m to 800 g/m and a shot blasting time of 0.1 sec/cm 2 or more to 60 sec/cm 2 or less.