| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide the manufacturing method of a seamless steel tube excellent in dimensional accuracy even when a mandrel mill is used. SOLUTION: In the manufacturing method of the seamless steel tube the dimensions of the tube body of which is finished with a hot stretch reducer after making a hollow tube stock by piercing a steel billet and elongating the hollow tube stock with the mandrel mill 5, the outside diameter is continuously measured at plural places of the outer periphery of the hollow tube stock (sheel) 8 on the outlet side of the mandrel mill and the interval between the rolls 6 and number of revolution of the rolls 6 at each stand of the mandrel mill 5 are adjusted so that those measured values are within the target range.</p> |
