DE2001880A1 - Joining lengths of strip for spiral tube mfe - Google Patents

Abstract

Wastage is reduced on spirally welded tube by joining successive sheets or plates so that the joint runs transverse to the axis of the finished tube. This is accomplished by cutting the strip at an angle to its centre line that is complementary to the winding angle of the strip. Plates may be rolled diagonally to produce a parallelogram shape to fit the above requirements.

Description

"Method of making a tape for the manufacture of pipes with helical weld seam and preliminary product "The invention relates to a method for making a band of great length all several bands of shorter length or Sheets for the production of pipes with a helical weld seam and a preliminary product for the procedure.

Long strips are commonly used to manufacture pipes with longitudinal or spiral seam by cropping and welding several strips together made at right angles to the longitudinal extension of the ligaments. The point of this manipulation is to be able to operate the pipe welding continuously zii and the start-up and To reduce energy losses.

In connection with the rolling of welded strips or sheets it is also already known to CLOSE the belts at an angle of 70 to nO to crop and weld their longitudinal extension, which should be avoided, that the weld seam in the subsequent rolling at the same time over the entire width is detected and causes an increased roller load.

This task is for bending a belt into a helical one Slotted tube of no importance, since also a right-angled or approximately right-angled butt seam running to the longitudinal direction of the strip because of the acute angle in the bending roll apparatus incoming strip not evenly over the entire width under the bending rollers device.

The present invention, however, assumes that a right-angled or an approximately right-angled butt seam on the finished welded pipe over a may extend considerable pipe length. This seam is undesirable and not permitted on high quality pipes. In many cases, it must be made from the finished product be separated out, whereby a poor output is caused. this applies especially if for reasons of pipe dimensions or material quality is not assumed from strips but from relatively short sheets. task of the invention is the loss associated with severing the butt joint to keep it as small as possible and thus improve the yield.

Under this task, the inventive method is only for the production of a band of great length for the production of tubes with a helical Weld seam meaningful. The production of the large 1> angular band takes place by cropping and joining individual shorter strips or sheets under one Angle that is different from 900 to the longitudinal extension of the strip or sheet. The invention is characterized in that the cropping and joining the Ribbons or sheets approximately below the EomAement - the addition to the right angle - the angle of entry which the direction of the longitudinal extension of the band and the rearward one Extension of the tube when the band is bent into a helical slot tube includes. Usually an inlet angle of about 25 to 650 is aimed for, which in the individual case depends on the bandwidth and the pipe diameter.

Already through this acquisition it is avoided that on the slowly working Pipe welding machine made a loss piece in more or less close succession will. In addition, it is assumed that sheets or strips are cut at right angles the loss can be used elsewhere as a sheet metal.

An even greater distribution is achieved if by belts or in particular Sheet metal is assumed, which already takes the form of a rallelogramrns when rolling have or received, with the short knot roughly below the complement of the inlet angle to extend the length of the strip or sheet. It will be because of it as well suggested, in the case of the above assumptions of metal sheets with a parallelogram shape that are made by diagonal rolling or ton of sheet metal or to run out of strips, which are produced by the fact that the sheet metal production used slabs e.g. continuously cast slabs at such an angle from the strand or cut off from the raw slab and, as usual, predominantly in its longitudinal direction are rolled out so that parallelogram-shaped sheets arise, the short edges of which run approximately below the complement of the inlet angle to the longitudinal axis of the sheet.

An exemplary embodiment is explained in more detail with reference to the drawing: The tube 2 is manufactured from the strip 1. This tape runs into the pipe production at the inlet angle 3. In the interruption 4 the auxiliary equipment be arranged for pipe production. The end 'of volume 1 and the beginning of subsequent band 5, are on the dashed lines 6 and 7 at the angle 8, which together with the inlet angle 3 results in a right angle, cropped and put together.

The type of cropping and joining is not essential for the process, E.g. the joining is done by submerged arc welding. Also in sections or continuous stapling is / is held sufficiently. Angenonimen in this example is that the sheets already had a corresponding approximate bevel during rolling and have been delivered with the dead ends as preliminary products for the process. One recognizes that the cropping ends cannot be much larger than with the right-angled cropping. The main advantage, however, is seen in that they welded together the butt joint 9 on the finished pipe 2 formed in a perpendicular to the pipe axis standing level and separated from the finished product without great loss can be.

- patent claims -

Claims (4)

Claims: 1. A method for producing a large tape Length from strips or sheets for the production of pipes with a helical weld seam by plucking and joining the strips or sheets at an angle that is different from 900 to the longitudinal extent of the strip or sheet, characterized in that that the cropping and juxtaposition of the strips or sheets approximately below the complement of the inlet angle takes place, which the direction of the longitudinal extension of the strip with the rearward extension of the tube axis when the band is bent into a helical shape Include slotted tube. 2. The method according to claim 1, characterized in that the tapes or sheets already have or receive the shape of a parallelogram during Walsen, with the kdræeren edges approximately below the complement of the inlet angle to the longitudinal extension of the strip or sheet. 3. The method according to claim 2, characterized in that of metal sheets with parallelogram shape is assumed, which are generated by diagonal rolling. 4. The method according to claim 2, characterized in that of metal sheets is assumed with parallelogram shape, which are generated in that the for Sheet metal production used slab e.g. continuously cast slab at such an angle cut from the strand or from the raw slab and, as usual, predominantly in theirs Is rolled out in the longitudinal direction so that parallelogram-shaped sheets are produced short edges approximately below the complement of the inlet angle to the longitudinal axis of the sheet get lost. Pre-product for a process according to Claims 1 to 4, consisting from a sheet metal with a parallelogram shape, which is produced by diagonal Walsen.