PURPOSE: To improve durability as a tool by preventing chipping of a central blade and eliminating abrasion of a boundary part with the central blade by constituting an outer peripheral blade of a high hard sintered body and the central blade of a super hard alloy, and by forming them in one body.
CONSTITUTION: As a blade body 16, a high hard composite sintered body 20 consisting of a base plate 17 of a super hard alloy and a high hard sintered body 19 containing more than 30volume% of either one of CBN integrally sintered on the surface corresponding to the front in the direction of rotation of a tool, diamond and their mixed body is used. A part of an outer peripheral blade 22 is made of the high hard sintered body 19 and a part of a central blade is made of a super hard alloy, and they are continuously molded and a cutting blade 23 is formed. Consequently, as abrasion resistance property of the outer peripheral blade 22 is maintained and tenacity is given to the part of the central blade 21, chipping of the central blade 21 due to thrust load at the time of cutting and cutting resistance are restrained. Additionally, as the central blade 21 and the outer peripheral blade 22 are integrally formed as the high hard composite sintered body 20, no soldered part is interposed on the boundary between the central blade 21 and the outer peripheral blade 22, and there is no fear of abrasion, either.
NAKANO KOICHI
FUKUOKA HITOSHI
KODERA YUICHI
