| 摘要 |
PROBLEM TO BE SOLVED: To provide a UOE steel pipe for line pipe, which is suitable for a steel pipe for high strength line pipe which is laid in a discontinuous permafrost zone and is excellent in deformability. SOLUTION: The UEO steel pipe for line pipe excellent in deformability is characterized in that the tensile strength in the axial direction of pipe is≥620 MPa and the relationship of a strain-hardening coefficient n from the strain of 1% and uniform elongation in the axial direction of the pipe, a nominal tube diameter D, a nominal thickness t and the coefficient of variationαof the outside diameter of the pipe satisfies expression (1):α=ΔG/D×100, whereinΔG is difference between the maximum value and the minimum value of the outside diameter of the pipe from the pipe end to 0.7D on the same base line, a=0.0255, b=-0.1476, c=0.2607, d=-0.0217, e=0.0007 and f=-0.0085. COPYRIGHT: (C)2009,JPO&INPIT
|
