Hardening of selected areas of an earth boring rockbit

摘要

Bearing surfaces or other selected areas of component parts of a rotary cone earth boring rockbit are carburized or otherwise surface enriched by the sequential steps of coating the selected surface area to be enriched with a non-water based composition capable of effecting a corrosive protective seal thereabout; covering the coated area with a predetermined applied thickness of a carbonaceous paste; drying the paste and thereafter, subjecting the component part to an elevated temperature below which the coating is pyrolyzed to fully austenize the part and achieve a desired case depth followed by quenching, tempering, and finished machining as required.