Method permitting the increase of operations of cold pilger mills and an apparatus for the embodiment of this method
AssigneeVallourec
InventorPierre Peytavin
Life of this patent
Estimating the term…
Abstract
The method consists of a cold pilgrim rolling mill to effect a recoil movement of the chuck upstream followed by a return to its original position, at least once per rolling cycle. The period during which the chuck is withdrawn with respect to its rolling position is used advantageously for example to carry out the rotation of the chuck and/or to cause a lubricant under pressure to circulate between the chuck and the pipe. The method is applied particularly to the rolling of pipes with a large section, with high reduction rates.
Claims5
A recoil apparatus for use on a cold pilger mill having a mandrel connected to a mandrel holding shaft, the mandrel located in a pipe blank contacted by grooved rolls which are mounted in a rolls carriage effecting an oscillating movement along the rolling axis of the pipe blank, the recoil apparatus recoiling the mandrel upstream from the pipe blank and thereafter returning the mandrel to its initial position, the recoil apparatus comprising:
- a shaft pincer mounted on the mill slideably with respect to the rolling axis, the shaft pincer seizing the mandrel holding shaft near its upstream end;
- an articulated holding part connected at a downstream position to the shaft pincer and at an upstream position to the mill, the articulated holding part having at least one pivoted joint along its length;
- and
- means connected to the pivoted joint for periodically pivoting the articulated holding part about its pivoted joint thereby temporarily shortening the distance between the shaft pincer and the upstream position of the mill connected to the articulated holding part;
- whereby the mandrel, holding shaft and shaft pincer are periodically shifted upstream and returned to their initial position.
An improved method for cold rolling a pipe blank on a pilger mill, the pilger mill comprising grooved rolls mounted on a rolls carriage to work the blank along the rolling axis between an upstream dead center and a downstream dead center, the pipe blank having a mandrel with decreasing diameter from upstream to downstream located therein, the method comprising the steps of:
- working the blank between the grooved rolls between the upstream dead center and dwonstream dead center;
- periodically advancing the mandrel upstream a distance of about 2-10 times the distance the blank is periodically advanced downstream and returning the mandrel;
- whereby an annular passage between the blank and mandrel is momentarily increased or created and reduced in size.
Dependencies are inferred from the claim text.