	US 12,448,850 B2
	Bearing materials for tricone bit rolling elements
Swetha Suresh, Chennai (IN); Gary C. Yerby, Morton, IL (US); Chetan V. Dahiwal, Chennai (IN); Thomas J. Yaniak, Peoria, IL (US); Michael A. Pershing, Washington, IL (US); Todd M. Blindt, Canton, IL (US); Scott A. Johnston, East Peoria, IL (US); Timothy F. Nusz, Wyoming, IL (US); Akilan Appavu, Chennai (IN); and Benjamin J. Bargfrede, Chicago, IL (US)
Assigned to Caterpillar Inc., Peoria, IL (US)
Appl. No. 18/293,064
Filed by Caterpillar Inc., Peoria, IL (US)
PCT Filed Jul. 20, 2022, PCT No. PCT/US2022/037656 § 371(c)(1), (2) Date Jan. 29, 2024, PCT Pub. No. WO2023/009357, PCT Pub. Date Feb. 2, 2023.
Claims priority of application No. 202111034145 (IN), filed on Jul. 29, 2021.
Prior Publication US 2024/0337160 A1, Oct. 10, 2024
Int. Cl. E21B 10/22 (2006.01)

CPC E21B 10/22 (2013.01)

11 Claims

9. A method of increasing the wear resistance of a roller cone drill bit, the method comprising:

adding a plurality of rolling elements to a bearing assembly within at least one cone of the roller cone drill bit;

wherein each rolling element of the plurality of rolling elements has a surface hardness of HRC 59-63, a hardened depth that is 0.5 mm to 3.0 mm deep, and is derived from a low carbon bearing steel material;

wherein the hardened depth is measured from the surface of each rolling element; and

wherein the low carbon bearing steel material has, by weight percent, from 0.12% to 0.25% carbon;

wherein the hardened depth comprises a carburized layer having a carbon content of at least 0.35% by weight at a depth of 0.5 mm to 3.0 mm from the surface of each rolling element.