BIT LEG AND CONE HARDFACING FOR EARTH-BORING BIT

摘要

An earth-boring bit has a bit body, and a bit leg depending from the bit body with a circumferentially extending outer surface, a leading side and a trailing side. A cone is rotatably mounted on a cantilevered bearing shaft depending inwardly from the bit leg. A first layer of a hardfacing composition of carbide particles dispersed in a nickel-based matrix is formed on the bit leg. A second layer of a hardfacing composition of carbide particles dispersed in an iron-based matrix that is formed on the cone. The first layer of hardfacing is applied by conveying carbide particles in a nickel-based matrix through a pulsed plasma transferred arc process. The second layer of hardfacing is applied with a torch and a hardfacing tube comprising carbide particles held within an iron-based tube.