DE2030802A1 - Process for reducing the stretching of pipes - Google Patents

Description

M 558

June 10, 1970 Li / Hel.

Company Friedrich Kooks,, 4 Düsseldorf, Freiligrathstrasse 1

Process for reducing the stretching of pipes

The invention relates to a method for reducing the creep Pipes, the Sohwachstellen, especially transversely su - flow direction have horizontal seams. Such cross seams occur inevitably in the case of mother pipes from longitudinal pipe welding systems in which, in continuous operation, the metal strips that are deformed into tubes are welded to one another in front of the system to form an endless belt will. Solo transverse seams are also created when seamless tubes are in front the stretch reduction to achieve large mother pipe lengths are welded together.

With stronger reductions it often happens that such weak spots tear when passing through the rolling mill as they are opposite have a lower tensile strength than the raw material.

Tube ruptures are very unpleasant in stretch-reducing mills because the continuous workflow is disrupted. When the scatter reducing mill, as is often the case, it is connected directly after a pipe welding system and with this in a continuous process works together, the entire system has to be shut down in the event of a pipe rupture large outsole lengths. Furthermore, as a result of pipe ruptures When cutting the pipes into certain lengths behind the reducing mill, different pipe sections that ensure the continuous process hinder in the further finishing and have to be sorted out. This pipe section «can even be so extremely short that they are

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jam in the roller tables and cooling beds, causing significant Malfunctions in the workflow or damage to the equipment can occur *

The invention is based on the problem of reducing stretching In any case, to avoid that pipe tears occur at the weak points.

Invention according to this object is achieved in that the train in Streokreduzierwalawerk lowered when going through a weak point will. This ensures that the weak points are not as before be exposed to the full tensile stress occurring in the stretch-reducing mill. A possibly larger scrap of pipes as a result of wall thicknesses lying outside the tolerance range, which are caused by the reduction of the tension in an area on both sides of the transverse seam, can be accepted in favor of the safer workflow be taken.

The transverse seams are preferably determined automatically before they enter the stretch-reducing mill, for example with the aid of the Eddy current method, so that the train of the rolling mill can be controlled automatically.

If the stretch-reducing mill is equipped with a group drive, the train can pass through the group of the be lowered at the highest move. With a single drive, the train only needs between the scaffolding when passing through the weak point to whom the Schwaohstelle is currently located, are lowered, which means the length of the neck can be kept very short.

The invention is illustrated in the drawing, for example and described in detail below with reference to the drawing.

According to the drawing, in which an application example of the invention

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is shown in a schematic representation, a stretch-reducing mill operates 2 together with a pipe welding system 4. The one in the direction of the arrow 6 incoming sheet metal strip 8 is initially in a Welding device 10 each with the preceding sheet metal strip 12 welded together to form an endless band. The connection is made Via a butt weld 14 »which is transverse to the direction of the Tape through the system.

The tape then runs through the pipe welding system 4, in which it is with Deformed with the help of rollers 14 to form a slotted tube and with a Induction welding device 16 is welded. '

The pipe 18 continuously running out of the pipe welding system then passes through any heating device 20 in which the tube is uniformly brought to the temperature required for reducing the stretching is brought. The heated pipe now runs through the Stretch-reducing mill 2, behind which it is with the help of a flying Saw 22 is cut into the required pipe lengths.

The stretch reducing mill 2 shown in the drawing is with a group drive is provided, which is fed via a main motor 24 providing a basic speed and an additional motor 26, whereby the additional motor, depending on the direction of rotation, adds an additional speed to the basic speed via a corresponding differential gear | or subtracted from it.

Immediately "v_ 'the reducing mill 2 is a sensing device 28 provided which automatically determines the passage of a transverse seam 14 and forwards a signal to the auxiliary motor 26. By this signal, the additional motor 26 is briefly during the run the transverse seam 14 is regulated by the reducing roller mill 2 in such a way that the 3ug is lowered in the pipe and thus the transverse seam 14 running through is not stressed too much. Pipe ruptures are in use of the method according to the invention are as good as excluded.

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It is true that the pipe is in one area on both sides of the transverse seam 14 have a somewhat thicker wall thickness as a result of the reduced train, so that the pipe ends cut from these parts may be outside the tolerance range. These pipes which can be easily identified by previously applied markings, can later be sorted out without difficulty.

The committee lengths can be kept short that the
Tension is not regulated down when the weak point enters the rolling mill, but only when it passes through the stands, between which the greatest tension is built up. Correspondingly, the tension can be increased again immediately when the weak point has passed through these scaffolding.

The inventive method is a continuous and A trouble-free process sequence is ensured in relation to pipe runs, which is particularly important in the system shown in the drawing, which is composed of several individual devices.

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Claims (3)

203G802 patent claims 1./ Process for reducing the stretching of pipes »the weak parts, in particular weld seams lying transversely to the direction of passage, characterized in that the Tension in the stretch-reducing mill is lowered when passing through the weak points. 2. The method according to claim 1, d a d u rc hh g e k e η η ζ e i c hn e t, that the weak point is automatically determined before entering the stretch-reducing mill. 3. Method according to claim 1 or 2, when used in a stretch-reducing mill with group drive, thereby marked ei c hn et, since 3 the pull when passing through the weak point the group of the largest train is lowered. 4- The method according to claim 1 or 2, when used in a stretch-reducing mill with single drive, d a d u r oh ge k e η η ζ e i c h η e t, that the tension when passing through the weak point is only lowered between the scaffolding between which there is the vulnerability is currently located. 109853/0857 Blank page