| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel plate for welded steel pipe and a welded steel pipe by which, in the static fracture of a high-strength welded steel pipe having a strength of≥750 MPa circumferential tensile strength, a base material part stably becomes a fracture origin and hereby the base material part having homogeneous metallic structure and mechanical properties certainly becomes a fracture origin at the static fracture of a steel pipe for pipeline. SOLUTION: In the steel plate for welded steel pipe, cross-direction tensile strength at both ends in a cross direction is≥750 MPa in the central part in a cross direction and also the difference between tensile strength at both ends and that in the central part is≥20 MPa. COPYRIGHT: (C)2003,JPO
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