| 摘要 |
A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned in recesses therein having polycrystalline diamond cutting elements mounted on said inserts. The inserts each also have a metal reinforcing shroud secured on the supporting face providing a reinforcement for the polycrystalline diamond cutting elements which is not subject to notch fracture. Each shroud is arranged so that a wall of the associated recess reinforces the shroud against shear forces and reinforces the stud against fracture.
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