Drill bit having diamond impregnated inserts primary cutting structure

摘要

An earth-boring bit comprises a bit body bit body in which are mounted a plurality of cutting structures inserts, wherein at least a portion of the cutting structures comprise diamond-impregnated inserts having a total thermal exposure of less than 25 minutes above 1500° F. The diamonds can be natural or synthetic diamond. The bit body itself may be diamond-impregnated, in which case it is preferred that the diamonds in the inserts make up at least 40% of the total diamond in the bit.