A drill bit including a bit body having an upper end adapted to be detachably secured to a drill string and at least one leg at its lower end, each leg having a downwardly and inwardly extending journal bearing, at least one roller cone mounted on each journal bearing, at least one cutting element disposed on the at least one roller cone; and a hardfacing overlay on at least a portion of at least one of an inner surface of the at least one roller cone and a surface of the journal bearing, wherein a composition of the hardfacing overlay proximate an outside surface of the hardfacing overlay is different from a composition of the hardfacing overlay proximate an interface between the hardfacing overlay and the at least a portion of at least one of the inner surface of the at least one roller cone and the surface of the journal bearing is disclosed.
CROSS-REFERENCES TO RELATED APPLICATIONS
This application, pursuant to 35 U.S.C. .sctn.119(e), claims priority to U.S. Provisional Application Ser. No. 60/695,975, filed on Jul. 1, 2005. That application is incorporated by reference in its entirety.
