Electric resistance welded steel pipe or tube and production method therefor

Abstract

Provided is a high-strength electric resistance welded steel pipe or tube having excellent SSC resistance. An absolute value of circumferential residual stress on a pipe or tube inner surface of the electric resistance welded steel pipe or tube is 10 MPa or more, and an absolute value of shear residual stress on the pipe or tube inner surface is 300 MPa or less. In a steel microstructure at a wall thickness center of a base metal portion of the electric resistance welded steel pipe or tube, a total volume fraction of ferrite and bainite is 90% or more and an average crystal grain size is 9.0 um or less. In a steel microstructure at a position 0.1 mm radially outward from the pipe or tube inner surface of the base metal portion, a total volume fraction of ferrite and bainite is 95% or more.

Dependencies are inferred from the claim text.