| 摘要 |
<p>The present invention provides a method of manufacturing a pipe or tube, comprising the step of rolling the pipe or tube by using a sizing mill comprising a plurality of stands each of which has a plurality of grooved rolls, wherein the grooved rolls are so configured that when tangents are drawn at edge parts facing to each other of adjacent grooved rolls at each stand, assuming that a minimum value of angles defined by the tangents in all stands is ² (deg), an outer diameter of the pipe or tube at an output side of the sizing mill is D (mm), and a thickness of the pipe or tube at the output side of the sizing mill is t (mm), the angle ² satisfies a following formula (1): ² ‰¥ 1.13 × 10 × Ln t / D × 100 + 1.37 × 10 2</p> |
