Method and apparatus for making cold-pilger-rolled tubes

An apparatus for making a cold-pilger-rolled tube, the apparatus comprising:

• a reciprocating roll frame;
• a thrust block upstream in a travel direction from the roll frame;
• a mandrel extending downstream in the travel direction from the thrust block into the roll frame;
• two grooved pilger rolls rotatable about respective axes in the reciprocating roll frame to compress a workpiece moving in the travel direction against the mandrel extending in the direction through a nip formed between the grooved rolls;
• means for measuring a wall thickness of the workpiece downstream in the travel direction from the rolls as the workpiece passes through the nip;
• and
• means for displacing the thrust block and mandrel in or transverse to the travel direction as the workpiece passes through the nip in accordance with the measured wall thickness to correct nonuniformities in the wall thickness determined from the measured wall thickness.