| 摘要 |
The present invention relates to a process and an apparatus for manufacturin g tubes, preferably from high-strength steels or special alloys, using the cold pilge r step-by-step process, with two roll stands that can be driven, at least intermittently, b ack and forth in opposite directions by crank drives, said roll stands having tapering groove d rolls that are driven by rack-and-pinion systems and roll over the rolled stock with altern ating directions of rotation. The present invention is characterised in that the greater part of the shapi ng work is performed on the first roll stand and a lesser part is performed on the second roll, w here additional smoothing is carried out; and in that in both roll stands reducing rolling i s carried out over a mandrel that is matched to the roll calibre; and in that the angular offset of the crank drive systems is so selected that the shaping zone on the first stand does not coi ncide in time with the shaping zone of the second stand. The present invention also relates to a machine for carrying out the process .
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