Threaded Joint for Oil and Well Pipe and Method for Manufacturing Same

Author:  Maeda, Jun
Source:  US Patent US 2007/0132238 A1
Doc ID:  2007041
Year of Publication:  2007
Abstract:  
A threaded joint for an oil well pipe in which a conventional threaded joint for an oil well pipe is improved so that sufficient fatigue fracture strength is secured, and a method for manufacturing the same are provided. An axial-direction residual stress of a threaded bottom part is set to -400 MPa or less as a value of X-ray stress analysis between a surface and a part with a depth of 40 flm.