SYSTEM, METHOD, AND APPARATUS FOR PASSIVE AND ACTIVE UPDRILL FEATURES ON ROLLER CONE DRILL BITS

摘要

Strategically placed hardfacing material (61, 71, 81, 91, 101, 111, 121) near the shank end (37) of a drill bit (31) above the transition edges (53) provides additional protection for compensator areas and the upper leg surfaces of drill bits during updrilling and/or backreaming operations. The strategically located hardfacing is typically passive in the normal drill mode, but active in the updrill drilling mode and/or backreaming. Alternative designs including other strategic material placement, the formation of hardfacing materials in tooth/wear design shapes, bi-metallic gage, graded composite hardfacing materials, recesses or cavities at edges of the outer diameter, and various methods of applying the material also may be employed.