The preferred embodiments are directed toward methods and apparatus for manufacturing components for earth-boring drill bits. In the preferred embodiments, a portion of the component is coated and the component is exposed to a carbon-rich environment at an elevated temperature. During this exposure, some portions of the component are not coated. The preferred embodiments further comprise coating the areas that were exposed to the carbon-rich environment and exposing the component to an elevated temperature in an environment with carbon present. In one embodiment, a drill leg is coated (with the exception of the journal pin) and then exposed to a carbon-rich environment at an elevated temperature. In this embodiment, the journal pin is then coated and the drill leg is exposed to an elevated temperature with a percentage of carbon that is less than the initial carbon-rich environment.
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims the benefit of 35 U.S.C. 111(b) provisional application Ser. No. 60/605,976 filed Aug. 31, 2004, and entitled Maintaining Carburized Case During Neutral To The Core Heat Treatment Processes
