| 摘要 |
A drill bit has a throw-away drill bit tip in the form of an insert (21, 31) secured to a shank (22, 32) to be mounted in a drilling tool. The insert (21, 31) is disengageably mechanically connected to the shank (22, 32) without any screws. The insert (21, 31) is formed of a silicon carbide whisker reinforced alumina sintered body, and the shank (22, 32) is made of steel. Due to this structure, the insert (21, 31) has an excellent wear resistance and an adhesion resistance. The shank (22, 32) has a sufficient toughness against breakage. Such a drill bit does not require any resharpening for continuous use during bit life.
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