04969378 is referenced by 26 patents and cites 7 patents.

A roller cutter (28) for a rotary drill bit (10) and method of making, utilizing an ion nitriding hardening process for the external surface (42) and the internal bearing surfaces (33, 34, 38) in the central cavity (30) of the roller cutter (28). The roller cutter (28) is made from a through hardenable steel and the ion nitrided hardened layer (77) has a total thickness less than around 0.030 inch. Hardened layer (77) has a relatively thick inner stratum (80) and a relatively thin outer surface stratum (78). The outer stratum (78) is formed of Fe.sub.4 N having a thickness no greater than around 0.0004 inch to form an outer surface which is ductile and has a relatively low friction coefficient.

Title
Case hardened roller cutter for a rotary drill bit and method of making
Application Number
7/420872
Publication Number
4969378
Application Date
October 13, 1989
Publication Date
November 13, 1990
Inventor
Eric F Drake
Pearland
TX, US
Mou Chih Lu
Houston
TX, US
Agent
Dodge Bush & Moseley
Assignee
Reed Tool Company
TX, US
IPC
B21K 5/02
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