| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a weld steel pipe having excellent buckling resistance. <P>SOLUTION: The method for production of the weld steel pipe includes a step of preparing an original pipe to be welded, and a step of expanding the whole length of the original pipe using a pipe-expanding head so that the undulation wavelength ratio D defined by formula (1): D=p/λ becomes 0.8 or less or 1.8 or more to obtain the weld steel pipe. In the formula (1), p is an undulation wavelength of the weld steel pipe in an axial direction, and λ is the buckling wavelength of Timoschenko defined by formula (2): λ=3.44×(r×t)<SP POS="POST">1/2</SP>(wherein r and t are respectively the inner diameter and thickness of the weld steel pipe). <P>COPYRIGHT: (C)2013,JPO&INPIT |
