Threaded steel pipe or tube and production method therefor
AssigneeJfe Steel Corporation
InventorsHiroshi Okano, Kazuki Matsubara, Shusaku Takagi, Nobuyuki Ishikawa
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Abstract
To alleviate stress exerted on a thread portion of a threaded steel pipe or tube during use to prevent fatigue fracture, there is provided a threaded steel pipe or tube having a female thread portion on an inner peripheral surface of at least one end, wherein a maximum value of residual compressive stress at a position of 0.4 mm in a depth direction from a thread bottom of the female thread portion is 100 MPa or more and less than or equal to tensile strength of a material of the threaded steel pipe or tube.
Claims8
A threaded steel pipe or tube having a female thread portion comprising a plurality of thread grooves on an inner peripheral surface of at least one end,
- wherein a maximum value of residual compressive stress at a position of 0.4 mm in a depth direction from each thread bottom of the plurality of thread grooves is 100 MPa or more and less than or equal to tensile strength of a material of the threaded steel pipe or tube.
Dependencies are inferred from the claim text.