| 摘要 |
<p>Disclosed are: a mandrel mill provided with a plurality of rolling stands, in which the rolling stands are provided with three grooved rolls, the three grooved rolls constitute a groove by the rolled surfaces, and when the diameter of the groove bottoms of the grooved rolls is defined as DR, the distance from the center of the groove to the groove bottoms of the grooved rolls is defined as DC/2, and the roll diameter ratio is defined as DR/DC, the set value of the roll diameter ratio DR/DC is not more than 3.7, and the set value thereof is desirably not more than 3.4; and a method for manufacturing a seamless pipe including a process for stretching and rolling a pipe material by the mandrel mill. Controlling the set value of the roll diameter ratio DR/DC in any of the rolling stands makes it possible to suppress the occurrence of overfill during the stretching and rolling of the pipe material.</p> |
