| US 7,469,618 B2 | ||
| Maintaining carburized case during neutral to the core heat treatment processes | ||
| Manikiran Bandi, Pearland, Tex. (US) | ||
| Assigned to Smith International, Inc., Houston, Tex. (US) | ||
| Filed on Aug. 25, 2005, as Appl. No. 11/211,261. | ||
| Claims priority of provisional application 60/605976, filed on Aug. 31, 2004. | ||
| Prior Publication US 2006/0042837 A1, Mar. 02, 2006 | ||
| Int. Cl. E21B 10/22 (2006.01) | ||
| U.S. Cl. 76—108.2 [175/371] | 14 Claims |
| 1. A method of manufacturing a component for a drill bit, comprising the following steps:
coating a first surface of the component while leaving a second surface of the component uncoated;
exposing the component to a first elevated temperature in an environment with a first concentration of carbon;
coating the second surface of the component; and exposing the component to a second elevated temperature in an environment with a second concentration of carbon;
wherein the first carbon concentration is approximately 0.6% to 0.9% and the second carbon concentration is approximately
0.13% to 0.22%.
|