Method and apparatus for the preparation of seamless tubes with a large ratio of diameter to strengthen people

摘要

The plant includes a continuous rolling mill followed by a tube widening unit (I) and then a finishing mill for calibrating or reducing the tube. Unit (I) includes a pair of profiled discs which rotate in opposite directions and between which is a rotary, conical mandrel used with the discs to reduce and then increase the dia. of the tube leaving the continuous mill. Both discs are eccentric w.r.t. the axis of the tube. The entry angle (Oe) of the tube into unit (I) is pref. 1.5-3 degrees, whereas its exit angle (Os) is pref. 4-9 degrees, esp. 4-6 degrees. The max. tube dia. which can be obtd. from a continuous prodn. line can be increased at relatively low investment cost.