Method for pilger rolling of tubes and mill for effecting same

Abstract

In the process of rolling a tubular billet with a mandrel is displaced in the rolling direction as it is simultaneously rotated about its longitudinal axis. Then a portion of the billet is advanced between the working rolls and is drawn over the mandrel during backward movement of the billet together with the mandrel. During forward movement of the billet with the mandrel, the billet is displaced relative to the mandrel in the same direction for a distance equal to that covered by the billet portion fed into the gap between the working rolls. The backward movement of the billet with the mandrel is effected at a speed substantially close to the peripheral speed of the working rolls at the starting moment of the drafting operation. The pilger mill comprises a stationary stand with continuously rotating working rolls. The mill also incorporates a billet feeding and turning mechanism and a billet gripping jaw kinematically linked with each other. The billet gripping jaw has screw nuts coaxially positioned therein and cooperating with a lead screw mounted together with the mandrel rod in a carriage. A tube turning mechanim has a tube gripping means accommodated in its body. Feeding and turning shafts in the billet feeding and turning mechanism are made hollow and formed with openings to receive respectively the lead screw and mandrel rod coaxially arranged therein.

Dependencies are inferred from the claim text.