| 摘要 |
A drill bit that includes a bit body, at least one roller cone attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on the at least one roller cone is disclosed. At least one of the plurality of cutting elements includes a first area defining a trailing edge, a second area proximate the first area defining a main wear surface, and a third area proximate the second area and defining a leading edge relief zone. Further, an insert for a drill bit that includes a contact portion adapted to contact an earth formation, the contact portion including a first area defining a relieved trailing edge, a second area defining a main wear surface, and a third area proximate the second area and defining a leading edge relief zone. Further, including an insert for a drill bit wherein a surface of the second area is a curved surface having a radius of curvature substantially equal to a radius of a borehole is also disclosed.
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