Manufacturing method of low residual stress seamless steel pipe for cutting rings with excellent straightness and roundness

摘要

PPROBLEM TO BE SOLVED: To provide a method for manufacturing a seamless steel pipe with low residual stress, which is long, keeps appropriate straightness and provides a ring cut from itself having excellent circularity. PSOLUTION: The method for manufacturing the seamless steel pipe with low residual stress superior in straightness and circularity includes moving the seamless steel pipe in the axial direction while rotating the seamless steel pipe around the central axis, when annealing it. In the above method, the seamless steel pipe is a thin-wall seamless steel pipe having a ratio (D/T) of an outside diameter to a wall thickness of 13 or more. PCOPYRIGHT: (C)2006,JPO&NCIPI