EP3436205A1

EP3436205A1 - Cold pilger rolling mill and method for producing a pipe

Info

Publication number: EP3436205A1
Application number: EP17713954.0A
Authority: EP
Inventors: Christofer HEDVALL; Udo RAUFFMANN; Thomas FROBÖSE
Original assignee: Sandvik Materials Technology Deutschland GmbH
Current assignee: Alleima GmbH
Priority date: 2016-04-01
Filing date: 2017-03-28
Publication date: 2019-02-06
Also published as: CN109070158A; US10974295B2; WO2017167750A1; JP7208009B2; CN117324371A; KR102343158B1; JP2019510639A; CA3018020A1; US20190151916A1; DE102016106035A1; KR20180132754A

Abstract

The invention relates to a cold pilger rolling mill (7') for cold-forming a bloom (11) to form a cold-hardened pipe (25), comprising a roll stand (1) having rollers (2) rotatably mounted thereon. In this respect, an object of the invention is to permit the rolling of long blooms that is as efficient as possible, without reducing the quality of the pipes to be produced. According to the invention, in order to achieve this object, the cold pilger rolling mill is to be configured in such a way that the cold pilger rolling mill has an unwinding device (26), wherein the unwinding device is configured and arranged in front of the front mandrel thrust block in the feed direction of the bloom such that a spindle, which can be rotated about an axis perpendicular to the feed direction of the bloom and with the bloom wound on same, can be received thereon, and during an operation of the cold pilger rolling mill, the bloom can be unwound and supplied between the chuck of the front mandrel thrust block and the mandrel bar to the feed clamping slide and the roll stand.

Description

Cold pilger rolling mill and method of making a pipe

The present invention relates to a cold pilger rolling mill for cold working a billet to a work hardened tube having a rolling stand with rollers rotatably mounted thereon, the rolling stand being in a direction parallel to a longitudinal axis of the billet between a reversing point in a feed direction of the billet and a feed direction of the billet Moving the rear turning point is motor driven back and forth, wherein the rollers during a reciprocating motion of the billet perform a rotational movement, so that the rollers in an operation of the cold pilger rolling mill roll the billet to a tube, a rolling mandrel, wherein the rolling mandrel of a Mandrel is supported at a rear end of the mandrel in the direction of advance of the mandrel such that in one operation of the cold pilger rolling mill, the billet is rolled from the rolls over the mandrel, at least one feed tension slide with a feed chuck attached thereto for receiving the billet, wherein the feed tension slide is reciprocable in a direction parallel to the longitudinal axis of the billet between a reversing point in the advance direction of the doll and a return point in the advancing direction of the doll such that the billet advances one step in an operation of the cold pilger rolling mill Direction to the roll mandrel learns, the feed chuck is up in such a way and zufahrbar that it releases or clamps the billet, and with at least one mandrel abutment with a chuck for holding the mandrel bar, with a front mandrel abutment in the feed direction of the billet before the feed tensioning slide is arranged in such a way that the mandrel rod can be held fast by the chuck of the front mandrel abutment in an operation of the cold pilger rolling mill, wherein the chuck of the front mandrel abutment can be driven up in the radial direction, so that a chunk between the chuck and the mandrel rod e is feasible. Moreover, the present invention relates to a method of manufacturing a tube by cold forming a billet in a cold pilger rolling mill having a rolling stand with rollers rotatably mounted thereon, a mandrel held by a mandrel bar, at least one mandrel stop holding the mandrel bar and at least one feed chuck with a feed chuck for receiving the mandrel Luppe with the steps:

a) driving on a chuck of a forward direction of the lance front mandrel abutment in the radial direction and passing a first billet through the front mandrel abutment, b) supplying the first billet to the feed tension slide and receiving the first billet by driving the feed chuck in the radial direction and clamping the first billet by moving the feed chuck in the radial direction at a forward feed point of the feed chuck, c) after complete execution the first billet by the front mandrel abutment driving the chuck of the front mandrel abutment in the radial direction such that the front mandrel abutment holds the mandrel rod carrying the mandrel,

d) rolling the first billet through the rolls over the rolling mandrel to a work hardened tube by incrementally advancing the first billet by means of the feed chuck and oscillating the roll stand back and forth between a front and a rear reversal point with the rolls.

For the production of precise metal tubes, in particular of steel, an extended hollow cylindrical blank is usually cold reduced in the fully cooled state by compressive stresses. In this case, the blank is formed into a tube with a defined reduced outer diameter and a defined wall thickness.

The most common pipe reduction method is known as cold pilgering, the blank being called a billet. The billet is rolled over a calibrated, i. pushed the inner diameter of the finished tube, rolling mandrel while calibrated from the outside of two calibrated, i. comprising the outer diameter of the finished tube defining rollers and rolled in the longitudinal direction over the rolling mandrel.

During cold pilgering, the billet undergoes incremental advance toward or beyond the mandrel, while the rolls are reciprocated horizontally over the mandrel and thus over the billet. The horizontal movement of the rollers is predetermined by a rolling stand on which the rollers are rotatably mounted. The roll stand is reciprocated in known Pilgerwalzanlagen by means of a crank mechanism in a direction parallel to the rolling mandrel, while the rollers themselves receive a rotational movement through a fixed relative to the rolling rack, engage firmly with the roller axes connected gears.

The feeding of the billet over the mandrel is carried out by means of a feed tension slide, which allows a translational movement in a direction parallel to the axis of the rolling mandrel.

At the beginning of the rolling process, the billet is pushed by a loading driver with rollers in the chuck of the feed tension slide. At the front in the direction of advance of the doll Point of reversal of the roll stand, which is also referred to as Eilauftotpunkt, the rolls reach an angular position in which the billet can be accommodated in the so-called inlet pockets of the rolls and between the rolls. The conically calibrated rollers stacked on top of one another in the rolling mill roll over the billet by rolling back and forth on the billet in the feed direction of the feed tension slide. In this case, during a rolling stroke of the roll stand, the pair of rolls moves a distance L from the front reversal point to the rearward reversing point of the rolling stand, also referred to as the discharge dead center, and extends the billet over the rolling mandrel held inside the billet.

The rollers and the rolling mandrel are calibrated so that the gap between the roller and rolling mandrel in the area of the working caliber of the rollers steadily decreases from the wall thickness of the billet to the wall thickness of the finished rolled tube. In addition, the outer diameter defined by the rolls decreases from the outer diameter of the billet to the outer diameter of the finished pipe and the inner diameter defined by the roll mandrel decreases from the inner diameter of the billet to the inner diameter of the pipe. In the adjoining region of the smoothing caliber of the rollers no reduction of the wall thickness of the tube to be produced takes place, but only a smoothing of the surface of the tube to be produced. Arriving at the outlet dead center, the finished rolled tube is released from the outlet pockets of the rollers.

An advancement of the billet between the rolls takes place either only at the front reversal point or both at the front and at the rear reversal point of the roll stand. By repeatedly rolling over each pipe section, i. Feed steps, which are significantly smaller than the distance of the roll stand between the front and rear reversal point, a uniform wall thickness and roundness of the tube, a high surface quality of the tube and uniform inner and outer diameter are achieved.

In order to obtain a uniform shape of the finished tube, the billet undergoes an incremental feed, intermittent rotation about its axis. The rotation of the billet takes place at both reversal points of the mill stand, i. then when the billet is released from the inlet and outlet pockets of the rolls, instead.

From the state of the art cold pilger rolling mills are known, which can work on billets with a length of up to about 15 m. However, if pipes of high quality, ie a uniform wall thickness and a high surface quality of the inner and outer surface, with a length of beyond 150 m needed so such pipes can not be produced in a cold pilger rolling mill according to the prior art. A manufacture of one-piece pipes with a length of more than 150 m in a cold pilger rolling mill requires a cold forming of billets whose length exceeds the length of Luppen, which can be rolled with conventional equipment, significantly exceeds. Compared with the prior art, it is therefore an object of the present invention to provide an apparatus and a method which make it possible to cold-roll billets having a length of 30 m or more. Another object of the present invention relates to a space-saving machining of billets having a length of 30 m or more, so that high-quality long pipes can be manufactured in a cold pilger rolling mill, and hence avoiding high costs due to the necessity of large workshops. Another object of the present invention is to roll long billets as efficiently as possible without reducing the quality of the pipes to be produced.

At least one of these objects is achieved by a cold pilger rolling mill for cold forming a billet to a work hardened tube having a rolling stand with rollers rotatably mounted thereon, the rolling stand in a direction parallel to a longitudinal axis of the billet between a forward in a feed direction of the billet reversing point and a in the feed direction of the Luppe rear reversing point is driven by a motor driven back and forth, wherein the rollers during a reciprocating motion of the billet perform a rotational movement, so that the rollers in an operation of the cold pilger rolling mill roll the billet to a tube, a rolling mandrel, said Roll mandrel is supported by a mandrel at a rear end of the mandrel in the direction of advance of the mandrel such that in one operation of the cold pilger rolling mill, the billet is rolled from the rolls over the mandrel, at least one feed tension slide with a feed chuck attached thereto in which the feed tension slide is reciprocable in a direction parallel to the longitudinal axis of the billet between a forward reversal point in the advance direction of the doll and a rearward reversing point in the advancing direction of the doll such that the billet advances one step in an operation of the cold pilger rolling mill experiences in one direction to the mandrel, wherein the feed chuck in such a radially up and is zufahrbar that it releases the chine or clamped, and with at least one mandrel abutment with a chuck for holding the mandrel bar, wherein a front mandrel abutment in the feed direction of Luppe is arranged in front of the feed clamping slide such that the mandrel rod is firmly held in an operation of the cold pilger rolling mill of the chuck of the front mandrel abutment, wherein the chuck of the front mandrel abutment is movable in the radial direction, so that a lump between the front mandrel Bearing and the mandrel bar is guided, and wherein the cold pilger rolling mill has an unwinding device, wherein the unwinding device is configured and arranged in the feed direction of the billet in front of the front mandrel abutment, that rotatable about an axis perpendicular to the feed direction of the doll Spindle with the coil wound thereon can be accommodated and unwindable in an operation of the cold pilger rolling mill and between the chuck of the front mandrel abutment and the mandrel bar the feed clamping slide and the rolling stand can be fed. In particular, lumps with a length of more than 30 m require a considerable amount of space when inserted into the cold pilger rolling mill. By means of the unwinding device according to the invention, a billet previously wound onto a spindle about a first axis can be introduced in a space-saving manner into the cold pilger rolling mill. In one embodiment, the unwinding device has a straightening device which, during the operation of the device, directs the wound, ie curved, slug, ie straightens it. An example of such a straightening device is a straightening machine, in particular a roll or skew rolling straightening machine. In this way, during unwinding of the billet, it is directed and at the same time loaded through the front mandrel abutment into the doll bed between the front mandrel repeller and feed chuck or between the front and rear mandrel abutments.

The unwinding device according to the invention for the billet thus ensures a more compact design of the overall arrangement of the cold pilger rolling mill, whereby the operating costs are further reduced.

In one embodiment of the invention, the distance between the unwinding device and the front end of the front mandrel abutment is less than the distance between the rear end of the front mandrel abutment and the forward end of the feed chuck feed of the rear feed chute at the rear reversal point of the rear chuck slide. In a further embodiment, the distance between the unwinding device and the front end of the front mandrel abutment is smaller than the distance between the rear end of the front mandrel abutment and the front end of the back mandrel abutment.

In one embodiment of the present invention, the forward mandrel abutment is at least 30 meters apart from the feed chuck as measured with the feed chuck at its rear reversal point.

Such a selected distance of the front mandrel abutment from the feed chuck allows the processing of slugs with a length of 30 m or more in a cold pilger rolling mill according to the invention. In this case, in one embodiment, the distance between the front mandrel abutment and the feed chuck is measured between that in the feed direction of the The rear end of the chuck of the front mandrel abutment and the front end of the feed chuck of the feed chute, the feed chuck being at its rear reversal point. The previously defined distance is at least 30 m and makes it possible to arrange a billet between the front mandrel abutment and the feed chuck of the feed tension slide so that both the chuck of the front mandrel abutment and the feed chuck of the feed tension slide closed, ie can be closed without clamping the billet or pinch. Accordingly, the distance between the front mandrel abutment and feed chuck approximately describes the length of the billet, which can be loaded into and rolled with the cold pilger rolling mill according to the invention.

When inserting the billet in the cold pilger rolling mill, the front mandrel abutment is opened by the chuck of the mandrel abutment is driven in the radial direction, so that the billet between the front mandrel abutment and the mandrel bar can be passed in the direction of the mandrel to. After the billet has left the front mandrel abutment, the chuck of the front mandrel abutment is retracted to hold the mandrel bar.

If in the sense of the present application of front and rear positions is mentioned, these positions are from the perspective of a viewer who looks along the billet in the direction of advance of the doll.

In one embodiment of the present invention, the distance between the front mandrel abutment and the feed chuck, measured with the feed chuck at its rear reversal point, is at least 40 m and in another embodiment at least 50 m.

In one embodiment of the present invention, the material of the mandrel bar of the cold pilger rolling mill has a tensile strength of 1000 N / mm ² or more, or 1500 N / mm ² or more.

In another embodiment of the present invention, the mandrel bar is a tube having an outer diameter, an inner diameter and a wall thickness. Tensile strength is a property of a material and describes the maximum mechanical tensile stress that the material endures before it breaks. The tensile strength is measured on the basis of the maximum achievable tensile force relative to the original cross-section of the sample to be measured. The mandrel supporting the mandrel must receive high forces during rolling of the billet, so that the material of which the mandrel is made must have high strength in terms of tensile strength.

Suitable materials for this purpose are, for example, tempered steels according to DIN EN 100 83, which receive high tensile and fatigue strength by tempering, ie hardening and tempering. The carbon content of tempered steels is usually between 0.2 and 0.65%, with different alloy contents of chromium, manganese, molybdenum and nickel mixed in different proportions depending on the intended use. Examples of alloyed tempered steels with a tensile strength of more than 1000 N / mm ² are the steel grades 42 CrMo 4, 34 CrNiMo 6 and 30 CrNiMo 8.

In addition, in one embodiment of the present invention, the mandrel bar has an elongation of 10% or less, and in one embodiment, 5% or less.

The elongation is an indication of the relative change in length of a sample under load, for example by a force or by a change in temperature. Also, a high extensibility of the mandrel bar is required in rolling to prevent the mandrel bar from breaking due to a large elongation. As well as high tensile strength, tempered steels are also suitable for ductility. For example, the tempered steel 30 CrNiMo 8 in addition to a tensile strength of 1000 N per mm ² and an elongation of 10% or less, and thus is suitable as a material for the mandrel bar according to the invention. In a further embodiment of the present invention, the cold pilger rolling mill has two feed clamping carriages each having a feed chuck attached thereto and a controller, wherein the controller is designed such that it controls the movement of the two feed chucks so that the chop always in a continuous operation of the cold pilger rolling mill alternately of one of the feed chuck is clamped and in the direction of the mandrel to stepwise advanceable, the front mandrel abutment of the feed chuck of the feed direction of the billet rear feed tension slide, measured with the feed tension slide at its rear reversing point, a distance of at least 30 m. In this way, a higher, ie continuous throughput of Luppen is made possible by the cold pilger rolling mill. This makes the rolling process more efficient and less expensive by saving on operating costs. In addition, no feed chuck with a long travel is needed, but the entire required travel is divided into two Subsections, so that each of the two feed tension slide only has to cover each one of the sections.

In another embodiment of the present invention, the cold pilger rolling mill has a rear mandrel abutment with a chuck for holding the mandrel in the advancing direction of the billet between the forward reversing point of the feed tension slide and the front mandrel abutment, the rear mandrel abutment spaced from the front mandrel abutment by at least 30 m has, in such a way that the mandrel bar during operation of the cold pilger rolling mill of at least one chuck of the front mandrel abutment or the rear mandrel abutment is firmly held.

The distance between the front and rear mandrel abutment is defined in one embodiment as the distance between the rear end of the front mandrel abutment in the advancing direction of the billet and the front end of the rear mandrel abutment in the advancing direction of the billet. A billet having a maximum length of this distance can therefore be loaded between the front and rear mandrel abutments, i. are arranged, while the chucks of the front and the rear mandrel abutment are closed and hold the mandrel bar, i. without pinching the doll. The provision of a back mandrel abutment between the front reversal point of the feed chute and the front mandrel abutment in addition to the front mandrel abutment enables the processing of a plurality of long lands, i. with a length of 30 m or more, in a continuous operation. If a billet has already completely passed through the rear mandrel abutment and is being rolled over the mandrel, the rear mandrel abutment is retracted to support the mandrel bar. The front mandrel abutment no longer needs to hold the mandrel bar and, in contrast to the rear mandrel abutment, can be driven up so that another chunk can be fed to the cold pilger rolling mill.

In one embodiment, the cold pilger rolling mill, in addition to a rear and a front mandrel abutment on two feed clamping slide, each with a feed chuck.

The cold pilger rolling mill according to the invention is consequently suitable for an efficient and cost-effective cold pilering of long slugs with a length of 30 m or more. In another embodiment of the present invention, each feed carriage of the cold pilger rolling mill is configured to feed a billet weighing 100 kg / m or more. In one embodiment of the invention, each feed chuck is configured to receive a billet having a weight in a range of between 100 kg / m and can feed 150 kg / m. In order to be able to advance particular Luppen with a length of at least 30 m and a weight per length between 100 kg / m and 150 kg / m with a feed tension slide, in one embodiment, the feed tension slide a correspondingly strong linear drive for advancing the billet on the rolling mandrel on. In addition, the chuck also has a correspondingly strong rotary drive for rotating the billet about its longitudinal axis.

In a further embodiment of the present invention, each feed carriage of the cold pilger rolling mill is designed such that it can advance a billet with a weight of 125 kg / m or more.

In one embodiment of the present invention, a winding device is arranged in the feed direction of the billet behind the rolls of the rolling mill, wherein the winding device for the tube produced in the rolling mill bending means for bending the tube such that it can be wound around a first axis, and a Holding frame, wherein the bending means and the first axis is pivotally received on the holding frame about a substantially parallel to the first axis and parallel to a longitudinal axis of a roller received between the rollers second axis. Such a space-saving design also reduces the cost of long tubes considerably, as can be dispensed with as a result of winding long tubes from a take-up on very large and especially very long halls.

Such a take-up device also makes it possible to pick up the finished tube that has emerged from the cold pilger rolling mill and to bend it in such a way that it can be wound up on a helical path. This arrangement saves a considerable amount of time in the production of steel tubes which are dimensioned so that they can be wound up. The expiring from the rolling mill tube can already be wound while introduced in the same strand still a doll in the pilgrim's mouth and formed between the rollers. In addition, the take-up device allows a considerable space saving for the cold pilger rolling mill as such, since in the manufacture of the pipe not the entire length of its full length must first run out of the rolling mill before it can be unwound or shot. An essential aspect of the take-up device is that the flexure and the first axis are pivotally mounted about a second axis. In this way, the winding device can pivot a movement, which the tube or the billet during rolling by the feed driven carriage performs, understand and the tube can be wound up without twisting. Without a corresponding pivotable mounting of the bending device and the first axis, there would be a twisting of the tube during winding and an associated significant loss of quality in the finished tube.

The second axis about which the bending device and the first axis are pivotably received on the holding frame, is parallel to the axis of symmetry of the finished outgoing from the rolling mill tube. In one embodiment, the second axis coincides with the axis of symmetry of the finished pipe leaving the mill stand.

In a further embodiment of the invention, the bending device and the first axis are driven by a motor to pivot about the second axis. Although the pivoting movement of the bending device can in principle also be effected by the pivoting movement of the finished tube leaving the rolling stand, a motor drive largely prevents the tube from undergoing torsional stresses when it is wound up. A detailed description of embodiments of such a winding device can be found in the German patent application 10 2009 045 640 A1.

In a further embodiment of the present invention, the feed chuck of the feed chuck is designed to be pivotable by motoring and takes up the chute pivotable about its longitudinal axis, and the cold pilger rolling mill also has a control which is set to operate the chuck during operation of the take-up chuck Bending device and the first axis of the winding pivoted synchronously with the same angular velocity. In such an embodiment, the bending device is accommodated on the holding frame so as to be able to be pivoted about the second axis by a motor. The "electronic wave" between the feed tension slide and the take-up device allows almost torsion-free winding of the finished tube.

Such a space-saving design also reduces the cost of long tubes considerably, as can be dispensed with as a result of winding long tubes from a take-up on very large and especially very long halls.

In a further embodiment of the present invention, the cold pilger rolling mill has an annealing furnace, which is designed such that in one operation of the cold pilger rolling mill, the billet is at a temperature in the range of 1000 ° C to 1200 ° C or in the range of 1050 ° C heated to 1 150 ° C. In one embodiment, the annealing furnace is designed in such a way that a billet wound on a spindle can be annealed in the annealing furnace. In one embodiment, therefore, the annealing furnace is a shaft furnace. In an alternative embodiment, the billet is heated in length in a continuous furnace to the temperatures listed above.

In a further embodiment of the present invention, the cold pilger rolling mill has a second cold pilger rolling mill for cold forming a billet such that a billet is deformable in the second cold pilger rolling mill to form the billet entering into an embodiment of the cold pilger rolling mill discussed above, such that the cold pilger rolling mill previously discussed is rolling mill is a two or more times rolled pipe.

In a further embodiment, each of the chuck of the individual mandrel abutment openings for inserting clamping jaws in such a way that at least three clamping jaws of a mandrel abutment engage the mandrel. This enables a simple, uncomplicated fixing of the mandrel bar by accessing the clamping jaws, so that during operation of the cold pilger rolling mill at least one mandrel abutment holds the mandrel bar, while the clamping jaws of the other mandrel abutments can be opened to pass a billet.

In one embodiment, the chucks of the respective mandrel abutments alternate the mandrel bar. Such alternate retention of the mandrel bar permits continuous operation in the cold pilger rolling mill so that one mandrel abutment holds the mandrel bar while the other mandrel abutments facilitate passage of a billet.

In accordance with the present invention, at least one of the above objects is also achieved by a method of manufacturing a tube by cold forming a billet in a cold pilger rolling mill having a rolling stand with rollers rotatably mounted thereon, a rolling mandrel held by a mandrel bar, at least one mandrel bar holding one Mandrel abutment and at least one feed tension slide with a feed chuck for receiving the billet with the steps:

a) driving on a chuck of a mandrel in the feed direction of the billet

Abutment in the radial direction and passing a first billet through the front mandrel abutment between the chuck of the front mandrel abutment and the mandrel bar,

b) after fully passing the first billet through the front mandrel abutment, driving the chuck of the front mandrel abutment in the radial direction such that the front mandrel abutment holds the mandrel bar carrying the mandrel, Feeding the first billet to a feed tension slide and picking up the first billet by driving the feed chuck in the radial direction and clamping the first billet by moving in the radial direction at a forward feed direction of the billet reversal point of the feed chute and

Rolling the first billet through the rolls over the rolling mandrel to a work hardened tube by incrementally advancing the first billet by means of the feed chuck and oscillating the roll stand back and forth between a leading and trailing reversal point with the rolls;

wherein prior to step a) in a step a ') providing the first billet wound on a spindle and unwinding of the first billet from the spindle with an unwinding takes place. Apart from the fact that the chuck of the mandrel abutment first closed, i. can be closed when the billet has completely passed through the chuck, the above numbering does not necessarily determine the order of the steps to be performed. In particular, feeding the billet to the feed chuck already takes place when the chuck of the front mandrel abutment is opened.

In one embodiment, when unwound, the billet wound on the mandrel passes through bending rolls which straighten the billet longitudinally again before the billet passes through the front mandrel abutment. The straight bending of the billet from its curved initial shape by the bending rolls takes place during the loading of the billet in the cold pilger rolling mill, i. while performing the billet through the anterior mandibular abutment, instead.

Such a method saves, as well as a take-up, a lot of space in the hall in which the cold pilger rolling mill stands, and consequently lowers the manufacturing costs for the long tubes manufactured in the cold pilger rolling mill.

The method according to the invention makes it possible to machine a long billet, in particular of billets with a length of 30 m or more, in a cold pilger rolling mill and consequently to transform the billet into a one-piece cold-worked tube having a length of at least 300 m. The finished tube has a very high quality due to the manufacturing process in a cold pilger rolling mill. This represents a significant advance over the prior art since prior art cold pilger mills can only machine billets up to a length of about 15 meters and consequently can only make tubes in one piece to a certain length. Therefore, in one embodiment of the present invention, the first billet has a length of 30 m or more.

An embodiment of the method according to the invention relates to a method for producing a tube with the additional step after step a) and before step b):

e) driving a chuck of a backward in the feed direction of the billet and between the front reversal point of a forward feed direction of the billet feed chute and the front mandrel abutment mandrel abutment in the radial direction, the rear mandrel abutment of the front mandrel abutment has a distance of at least 30 m, and Passing the first billet through the back mandrel abutment, the rolling of the first billet through the rolls above the mandrel into a work hardened tube in step d) by advancing the first billet alternately by means of the forward feed chuck from a forward turning point to a rear turning point the front feed tension slide and with the aid of a forward feed tension slide in the feed direction of the doll from a front reversal point to a rear reversal point of the rear feed tension slide and oscillatory forward and backward movements n of the roll stand is between a front and a rear reversal point with the rollers,

and wherein the method additionally comprises the steps of:

f) after fully passing the first billet through the rear mandrel abutment, driving the chuck of the rear mandrel abutment in the radial direction such that the rear mandrel abutment holds the mandrel bar carrying the mandrel,

g) during the rolling of the first billet unwinding of a second, on a wound about an axis perpendicular to the feed direction of the doll spindle spindle arranged unwound,

h) driving the chuck of the front mandrel abutment and passing the second billet through the front mandrel abutment into the area between the front mandrel abutment and the back mandrel abutment,

i) after fully passing the second billet through the front mandrel abutment, retracting the chuck of the front mandrel abutment so that the front mandrel abutment holds the mandrel bar carrying the mandrel; j) driving the chuck of the rear mandrel abutment;

k) passing the second billet through the rear mandrel abutment, I) feeding the second billet to the front feed chuck and picking up the second chunk in the feed chuck of the front feed chuck and clamping the second chunk by driving the feed chuck of the front feed chuck in the radial direction, m) driving the feed chuck of the rear feed chuck in the radial direction,

n) stepwise advancement of the second billet alternately with the aid of the front feed tension slide and the rear feed tension slide with the second set clamped in place,

o) after complete discharge of the tube finished from the first billet from the rolling stand inserting the second billet into the rolling stand; and p) rolling the second billet through the rolls over the rolling mandrel to a work hardened tube by incrementally advancing the second billet alternately by means of the back feed chute and the front feed chute, and oscillating the roll stand back and forth between a front and a backward reversal point with the rollers.

Such a method enables cold pilgering of long billets, i. Blades having a length of 30 m or more, in a continuous operation, so that a first billet is rolled, while a second billet is already introduced into the cold pilger rolling mill. This is made possible in particular by the presence of two mandrel abutments. A mandrel abutment must always be closed in such a way that it holds the mandrel bar during rolling. In the case of two mandrel abutments, one forward and one back, a mandrel abutment holds the mandrel bar firmly in place while the other mandrel abutment is open to pass a second stake. The operation in the cold pilger rolling mill is thus accelerated by the presence of at least two mandrel abutment.

While the front and the rear feed clamping slide advances the second billet alternately in the direction of the rolling mandrel, the first billet also receives a further advance in the direction of the rolling mandrel. The advance of the first billet takes place in this stage of the process indirectly by the alternating linear drive of the front and rear feed chute by the first billet is pushed by the advanced with the front and the rear feed clamping slide second billet. A further embodiment of the present invention relates to a method for producing a tube, in which a winding of an already finished rolled part of the billet takes place simultaneously with the rolling of a part of the billet to be rolled to a work-hardened tube with the steps of: bending an already finished rolled part of the billet in a bender, spirally winding an already finished rolled part of the billet about a first axis and pivoting the bender received on a support frame and the first axis about a substantially to the first axis vertical and parallel to a longitudinal axis of a roller received between the rollers Luppe second axis such that the pivoting takes place at the same angular velocity as a pivoting of the billet about its longitudinal axis during the rolling of the billet takes place.

In the method of this type, the already rolled part of a billet, i. the part of the already finished tube wound with the aid of a winding around a first axis, while at the same time a further part of the billet is still rolled out of the rolling stand on the roll stand rollers on the rolling mandrel and possibly another part of the billet still in the direction of Pilgrims mouth is introduced. The winding in the winding takes place in such a way that the already finished tube is first curved in a bending device. As a result of the curvature, the tube is then spirally wound around a first axis, wherein in addition to the winding, the bending device and the first axis are pivoted about a second axis. The second axis extends substantially perpendicular to the first axis and parallel to a longitudinal axis of a received between the rollers Luppe. In one embodiment, the second axis coincides with the longitudinal axis of the received billet. In addition, the pivoting of the bending device and the first axis about the second axis at the same angular velocity as a pivoting of the billet about its longitudinal axis, so that twisting of the tube during winding and an associated significant loss of quality is avoided in the finished tube. A further embodiment of the method according to the invention for producing a pipe is characterized in that prior to the passage of the billet through the front mandrel abutment, the billet wound on a spool is heated to a temperature in a range of 1000 ° C to 1200 ° C. In particular, in one embodiment of the method according to the invention, the billet is heated to a temperature in a range of 1050 ° C to 1 150 ° C.

In a further embodiment of the method according to the invention before the annealing of the billet further cold forming of the billet in a second cold pilger rolling mill such that the finished tube is prepared by multiple cold forming a billet. By a multiple cold forming a billet, the tensile strength of the finished tube is further increased, so that the finished tube after repeated cold forming a billet has an increased load capacity. Further advantages, features and applications of the present invention will become apparent from the following description of embodiments thereof and the accompanying figures. Figure 1 shows a schematic side view of the construction of a cold pilger rolling mill with an unwinding device according to an embodiment of the present invention.

Figure 2 shows a schematic side view of the construction of a cold pilger rolling mill with an unwinding device, a front and a rear mandrel abutment and two feed clamping slide according to another embodiment of the present invention.

Figure 3 shows a schematic side view of the structure of a cold pilger rolling mill with an unwinding device, a front and a back mandrel abutment, two feed clamping slide and a winding device according to another embodiment of the present invention.

In the figures, identical elements are designated by identical reference numerals.

In Figure 1, the structure of a cold pilger rolling mill according to the invention is shown schematically in a side view. The cold pilger rolling mill 7 consists of a rolling mill 1 with an upper roll 2 and a lower roll 3, a calibrated rolling mandrel 4 (in the figure, the position of the rolling mandrel is denoted by the reference numeral 4), a mandrel 4 carrying the mandrel 4, a feed clamping slide fifth with a feed chuck 12 for receiving a billet 1 1, a front mandrel abutment 15 with a chuck 19 and a discharge chuck 18 with a chuck 22. In the illustrated embodiment, the cold pilger rolling mill on a linear motor 6 as a direct drive for the feed clamping slide 5 on. Like all embodiments of FIGS. 1 to 3, the cold pilger rolling mill 7 has an unwinding device 26 for spreading the billet 11. The unwinding device 26 ensures that a on a spindle 27 wound around a to the feed direction of the doll 1 1 axis 28 wound doll is unwound. In this case, a motor-driven rotation of the spindle 27 takes place about the first axis 28 in the direction of the illustrated arrow, so that the ball wound on the spindle 27 is guided between five bending rolls 32a. Three bending rolls 32a are arranged in an upper row and two bending rolls 32a are arranged in a lower row. The bending rolls 32a bend the passed billet uniformly and in respectively opposite directions such that the billet between the bending rolls 32a is bent and straightened before being passed through the chuck 19 of the front mandrel abutment 15. The straightening of the billet 1 1 from its curved starting length takes place during the loading of the billet 1 1 through the front mandrel abutment 15 in the cold pilger rolling mill 7.

The integration of an unwinding device 26 in the cold pilger rolling mill as shown in the figures and thus the Abwickeins in the rolling process is particularly advantageous in Luppen with a length of 30 m or more. By unwinding a wound arranged doll 1 1 of the spindle 27 and a simultaneous feeding of the billet 1 1 to and through the front mandrel abutment 15 can save a lot of space in a hall in which the cold pilger rolling mill is located.

During cold pilgering on the cold pilger rolling mill shown in FIG. 1, the billet 11 undergoes a gradual advance in the direction of the rolling mandrel 4 towards or beyond it, while the rolls 2, 3 rotate over the rolling mandrel 4 and thus over the billet 1 1 horizontally reciprocated. In this case, the horizontal movement of the rollers 2, 3 through the roll stand

I specified, on which the rollers 2, 3 are rotatably mounted. The roll stand 1 is by means of a crank drive 23 via a push rod 24 in a direction parallel to the longitudinal axis of the billet between a front in the feed direction of the billet 1 1 reverse point 9, this is also referred to as Einlauftotpunkt ET, and one in the feed direction of the billet 1 1 rear Turning point 10, this is also referred to as the discharge dead center AT, reciprocated. The rollers 2, 3 themselves receive their rotational movement through a relative to the rolling stand 1 fixed rack (not shown), in the fixedly connected to the roller axes gears (not shown) engage. The feed of the billet 1 1 on the rolling mandrel 4 is carried out with the aid of the feed tension slide 5, which allows a translational movement in a direction parallel to the axis of the billet 1 1. The feed tension slide 5 thereby performs a reciprocating motion between a direction of feed of the billet 1 1 front reversal point 13 and in the feed direction of the billet

I I rear reversing point 14 off. The travel of the feed tension slide 5 between the two reversal points 13, 14 is 24 m in the embodiment of FIG.

Once the billet 1 1 has left the front mandrel abutment 15, the chuck 19 of the front mandrel abutment 15 is closed in the radial direction, ie closed, so that the chuck 19, the mandrel 8 firmly clamped. In this case, the front mandrel abutment 15 in Figure 1 of the feed chuck 12 of the feed tension slide 5, when the feed tensioning slide 5 is located at its rear reversal point 14, a distance of 36 m. This distance is measured between the forward direction of the billet rear end of the chuck 19 of the front mandrel abutment 15 and the forward direction of the billet front end of the feed chuck 12 of the feed tension slide when this is at his rear reversing point 14 is located. A billet with a maximum length of 36 m could thus be placed between the front mandrel abutment 15 and the feed chuck 12 of the feed chute 5 located at its rear reversal point 14, without the chunk of the chuck 19 of the front mandrel abutment 15 or the feed chuck 12 of the feed chute 5 would be clamped or clamped.

The mandrel 8 in Figure 1 consists of the material 30 CrNiMo 8 and has a tensile strength of 1000 N / mm ² and an elongation of 8%. At the front in the feed direction of the billet 1 1 turning point 9 of the roll stand 1, the Luppel 1 enters between the rollers 2, 3 and is of the inlet exchanges (not shown) of the rollers 2, 3 added. The rolling mill 1 arranged one above the other conical calibrated rollers 2, 3 rolled over the billet 1 1 by rolling on the billet 1 1 in the feed direction of the feed tension slide 5 back and forth. The roller pair moves during a rolling stroke by a distance L from the front in the feed direction of the rolling stand 1 (entry dead center ET) to the feed direction of the doll rear reversal point 10 (outlet dead center AT) of the rolling stand 1. This corresponds to Figure 1 of a rotation of the rollers at an angle of 280 °. The roller pair 2, 3 stretches the billet 1 1 over the rolling mandrel 4 held inside the billet 11. The rolls 2, 3 and the rolling mandrel 4 are calibrated in such a way that the gap between the rolls 2, 3 and the rolling mandrel 4 in FIG the working caliber zone of the rollers 2, 3 steadily reduced by the wall thickness of the billet 1 1 to the wall thickness of the finished rolled tube 25. In addition, the outer diameter defined by the roll from the outer diameter of the billet to the outer diameter of the finished pipe and the inner diameter defined by the rolling mandrel from the inner diameter of the billet to the inner diameter of the pipe decreases. After the working caliber zone of the rollers 2, 3 follows the smoothing caliber zone of the rollers 2, 3, in which a smoothing of the surface of the tube 25 to be produced takes place. Upon reaching the rear turning point 10 of the rolling mill 1, the discharge pocket (not shown) of the rolls 2, 3 releases the finished rolled tube. In order to obtain a uniform shape of the finished tube 25, the billet learns 1 1 next to a feed an intermittent rotation about its longitudinal axis. The rotation of the billet 1 1 takes place at both reversal points 9, 10 of the roll stand 1. By multiple rolling over each pipe section a uniform wall thickness and roundness of the tube and uniform inner and outer diameter are achieved.

The finished tube 25 is taken up by a chuck 22 of a discharge clamping slide 18 and pulled out of the cold pilger rolling mill 7. FIG. 2 shows a schematic structure of another cold pilger rolling mill 7 'according to the invention in a side view. In contrast to FIG. 1, however, the cold pilger rolling system 7 'illustrated in FIG. 2 has two feed clamping carriages 5, 5', each with one feed chuck 12, 12 'for receiving a billet 11. The two feed clamping slides 5, 5 'can be moved between their front 13, 13' and rear reversal points 14, 14 'in each case by 12 m and are characterized in comparison to the feed tension slide 5 shown in Figure 1 accordingly by a smaller travel.

The advance in the feed direction of the billet 11 feed clamping slide 5 'has already advanced the billet to just before his rear reversal point 14' in the direction of the rolling mandrel 4. The feed direction of the billet 1 1 rear feed tensioning carriage 5 is the front feed tensioning carriage 5 'counter to the feed direction of the billet, so that the front feed tensioning slide 5', when he arrived at its rear reversal point 14 ', the rear feed tension slide 5 at the front reversal point thirteenth the doll 1 1 can pass. After the inclusion of the billet 1 1 of the rear feed tension slide 5 this would in the next step, the billet 1 1 gradually in the direction of the mandrel 4 to move, while the front feed clamping slide 5 'would return to its front reversing point 13' to another Pick up the lupe 1 1 '. In this way, a continuous operation of the rolling mill is enabled, which avoids dead times in the return of a single feed tension slide 5 as shown in Figures 1 and 2 from its rear to its front reversal point.

In contrast to the cold pilger rolling mill 7 shown in FIG. 1, the cold pilger rolling mill 7 'from FIG. 2 also has, in addition to the front mandrel abutment 15, a mandrel abutment 16 in the direction of advance of the billet 11. The rear mandrel abutment 16 is arranged between the front reversal point 13 'of the front feed tension slide 5' and the front mandrel abutment 15 and, like the front mandrel abutment 15, has a chuck 20 for holding the mandrel 8. The billet 1 1 in Figure 2 has already left the front mandrel abutment 15, so that the chuck 19 of the front mandrel abutment 15 is closed and the mandrel 8 firmly clamped. The chuck 20 of the rear mandrel abutment 16, however, is driven up and lets the billet 1 1 pass between the chuck 20 and mandrel 8.

In FIG. 2, the distance between the front mandrel abutment 15, measured at the rear end of the chuck 19 in the feed direction of the chunk, and the rear mandrel abutment 16 is 38 m, while the stalk 1 1 shown in FIG. 2 has a length of 37 m. Accordingly, the billet 1 1 between the front 15 and rear mandrel abutment 16 are arranged and the chucks 19, 20 of both mandrel abutment 15, 16 can be fed without the chuck 19, 20 clamp the billet 1 1. FIG. 3 shows a cold pilger rolling system 7 "according to the invention in a schematic side view, which in addition to the two feed clamping carriages 5, 5 ', the front 15 and the rear mandrel abutment 16 still has a winding device 30 in comparison to the cold pilger rolling mill 7' shown in FIG ,

In order to be able to wind the finished tube 25 into a transportable form behind the rolling stand 1, a winding device 30 is additionally provided in the cold pilger rolling mill 7 "shown in Figure 3. The winding device 30, which is shown schematically in Figure 3, consists of a holding frame 33 and a bending device 31. The bending device 31 has three bending rollers 32b, which are all motor-driven in the illustrated embodiment and frictionally engage the finished tube 25 into engagement.

The already finished rolled part of the billet, i. the part of the already finished tube 25 is initially received by a chuck 22 of a discharge chuck 18 and pulled in the direction of the take-up device 30. As soon as a part of the already finished tube 25 gets between the bending rolls 32b of the bending device 31 of the winding device 30, this part of the finished tube 25 is first curved by two bending rolls 32b arranged above the finished tube 25 and a bending roll 32b arranged below the finished tube 25. As a result of a motor-driven rotation of the winding device 30 in the direction of the arrow shown in Figure 3, the curved portion of the finished tube 35 is wound spirally around a first axis 34 around.

The bending device 31 and the three bending rolls 32b are also pivotally attached to the holding frame 33 about a second axis 35 which coincides with the longitudinal axis of the finished tube 25 emerging from the export clamping slide 18. In this case, the pivoting movement of the bending rolls 32b about the second axis 35 takes place by means of a motor drive. The simultaneous taking place with the winding pivoting is performed at the same angular velocity as the pivoting movement of the billet 1 1 about its longitudinal axis during the rolling of the billet 1 1. Both Verschwenkbewegungen therefore take place synchronously to each other. This has the advantage that a twisting of the finished tube 35 during winding completely, but at least substantially, is avoided and the finished tube 25 is wound without torsional stresses during rolling. In addition, an annealing furnace 29 is provided in the same workshop in which the billet 1 1 is annealed before entering the pilgrim rolling mill 7 "'and after a first rolling in a second cold pilger rolling mill. For purposes of the original disclosure, it is to be understood that all such features as will become apparent to those skilled in the art from the present description, drawings, and claims, even if concretely described only in connection with certain other features, both individually and separately any combination with other of the features or feature groups disclosed herein are combinable, unless this has been expressly excluded or technical conditions make such combinations impossible or pointless. On the comprehensive, explicit representation of all conceivable combinations of features is omitted here only for the sake of brevity and readability of the description. While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description is exemplary only and is not intended to limit the scope of the invention as defined by the claims. The invention is not limited to the disclosed embodiments.

Variations of the disclosed embodiments will be apparent to those skilled in the art from the drawings, the description and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are claimed in different claims does not exclude their combination. Reference signs in the claims are not intended to limit the scope of protection.

LIST OF REFERENCE NUMBERS

I rolling stand

2, 3 upper, lower roller

4 rolling mandrel

5 feed tension slides

6 linear motor

7, 7 ', 7 "cold pilger rolling mill

8 mandrel

9 front reversal point of the roll stand

10 rear turning point of the rolling stand

I'm a doll

12 feed chuck

13 front reversal point of the feed tension slide 14 rear reversal point of the feed tension slide

15 front spine abutment

16 rear spine abutment

18 outlet tension slide for finished pipe

19, 20, 22 chucks

23 crank drive

24 push rod

25 finished pipe

26 unwinding device

27 spindle

28 first axis (unwinding device)

29 annealing furnace

30 take-up feed

31 bending device

32a, 32b bender

33 holding frame

34 first axle (take-up device)

35 second axle (take-up device)

Claims

P a n t a n s p r e c h e

Cold pilger rolling mill (7, 7 ', 7 ") for cold forming a billet (1 1) to a work hardened tube (25) with a roll stand (1) with rotatably mounted rollers (2, 3),

wherein the roll stand (1) in a direction parallel to a longitudinal axis of the billet (1 1) between a in a feed direction of the billet (1 1) front reversal point (9) and in the feed direction of the doll rear reversal point (10) is driven by a motor and is movable,

wherein the rollers (2, 3) during a reciprocating movement of the billet (1 1) perform a rotational movement, so that the rollers (2, 3) in an operation of the cold pilger rolling mill (7, 7 ', 7 ") the billet ( 1 1) roll to a tube (25), a rolling mandrel (4),

wherein the rolling mandrel (4) is supported by a mandrel rod (8) on a rear end of the mandrel rod (8) in the feed direction of the billet such that in one operation of the cold pilger rolling mill (7, 7 ', 7 ") the billet (11) is rolled by the rollers (2, 3) over the rolling mandrel (4),

at least one feed tension slide (5) with an attached feed chuck (12) for receiving the lead (1 1),

wherein the feed tension slide (5) in a direction parallel to the longitudinal axis of the billet (1 1) between a in the feed direction of the billet (1 1) front reversal point (13) and in the feed direction of the doll rear reversal point (14) so reciprocally movable is that the billet (1 1) undergoes a stepwise advance in one direction on the rolling mandrel (4) in an operation of the cold pilger rolling mill (7, 7 ', 7 "),

wherein the feed chuck (12) can be opened and closed in the radial direction in such a way that it releases or clamps the chunk (11),

and at least one mandrel abutment with a chuck for holding the mandrel bar (8),

wherein a front mandrel abutment (15) in the feed direction of the billet (1 1) in front of the feed tension carriage (5) is arranged such that the mandrel bar (8) in an operation of the cold pilger rolling mill (7, 7 ', 7 ") of the chuck (19 ) of the front mandrel abutment (15) is firmly held,

wherein the chuck (19) of the front mandrel abutment (15) in the radial direction is retractable, so that a billet (1 1) between the chuck (19) and the mandrel rod (8) can be passed,

characterized in that

the cold pilger rolling mill (7, 7 ', 7 ") has an unwinding device (26), wherein the unwinding device (26) designed in such a way and in the feed direction of the billet (1 1) before the front mandrel abutment (15) is arranged, that on her to a to the feed direction of the billet (1 1) vertical axis (28) rotatable spindle (27) with the wound thereon doll (1 1) is receivable and in an operation of the cold pilger rolling mill (7, 7 ', 7 "), the billet (1 1) unwound and between the chuck (19) of the front mandrel abutment (15) and the mandrel bar (8) the feed clamping slide (5) and the roll stand (1) can be fed.

Cold pilger rolling mill (7, 7 ', 7 ") according to claim 1, characterized in that the front mandrel abutment (15) of the feed chuck (12), measured with the feed tension slide (5) at its rear reversal point (14), a distance of at least 30 m.

Cold pilger rolling mill (7, 7 ', 7 ") according to claim 1 or 2, characterized in that the mandrel bar (8) has a tensile strength of 1000 N or more.

Cold pilger rolling mill (7, 7 ', 7 ") according to one of the preceding claims, characterized in that the mandrel rod (8) has an elongation of 10% or less.

Cold pilger rolling mill (7 ', 7 ") according to one of the preceding claims, characterized in that the cold pilger rolling mill (7', 7") comprises two feed clamping carriages (5, 5 ') each having a feed chuck (12, 12') attached thereto and a controller wherein the controller is configured such that it controls the movement of the two feed carriages (5, 5 ') such that the lugs (11, 11') in a continuous operation of the cold pilger rolling mill (7 ', 7 ") respectively alternately by one of the feed chuck (12, 12 ') are clamped and in the direction of the rolling mandrel (4) are gradually advanced, the front mandrel abutment (15) of the feed chuck (12) in the feed direction of the billet rear feed tension slide (5) , measured with the feed tension slide (5) at its rear reversal point (14), a distance of at least 30 m.

Cold pilger rolling mill (7 ', 7 ") according to one of the preceding claims, characterized in that the cold pilger rolling mill (7', 7") a rear mandrel abutment (16) with a chuck (20) for holding the mandrel rod (8) in the feed direction of the billet (1 1) between the front reversal point (13) of the feed tension slide (5) and the front mandrel abutment (15), wherein the rear mandrel abutment (16) from the front mandrel abutment (15) has a distance of at least 30 m such that Mandrel (8) during operation of the cold pilger rolling mill (7 ', 7 ") of at least one chuck (19, 20) of the front mandrel abutment (15) or the rear mandrel abutment (16) is festhaltbar.

Cold pilger rolling mill (7, 7 ', 7 ") according to one of the preceding claims, characterized in that each feed slide (5, 5') of the cold pilger rolling mill (7, 7 ', 7") is designed such that it has a billet (11 ) with a weight of 100 kg / m or more can advance.

Cold pilger rolling mill (7 ") according to one of the preceding claims, characterized in that a winding device (30) in the feed direction of the finished tube (25) behind the rollers (2, 3) of the cold pilger rolling mill (7") is arranged, wherein the Aufwickelvorrich- device (30) for the tube (25) manufactured in the cold pilger rolling mill (7 "), a bending device (31) for bending the tube (25) such that it can be wound around a first axis (34), and a holding frame (33) wherein the bending device (31) and the first axis (34) are parallel to a second axis parallel to the first axis (34) and parallel to a longitudinal axis of a billet (11) received between the rollers (2, 3) ( 35) is pivotally received on the holding frame (33).

Kaltpilgerwalzanlage (7 ") according to one of the preceding claims, characterized in that the cold pilger rolling mill (7") has an annealing furnace (29) which is designed such that it in a state of the cold pilger rolling mill in a wound state, the billet (1 1) heated to a temperature in a range of 1000 ° C to 1200 ° C.

0. A method for producing a tube (25) by cold forming a billet (1 1) in a cold pilger rolling mill (7, 7 ', 7 ") with a roll stand (1) rotatably mounted thereon rollers (2, 3), one of Mandrel (4), at least one mandrel abutment (15, 16) holding the mandrel rod (8) and at least one feed chuck (5) with a feed chuck (12) for receiving the stake (11), comprising

a) driving a chuck (19) in the feed direction of the billet (1 1) front mandrel abutment (15) in the radial direction and passing a first billet (1 1) through the front mandrel abutment (15) between the chuck (19) of the front mandrel abutment (15) and the mandrel bar (8),

b) after the complete introduction of the first billet (11) through the front mandrel abutment (15), the chuck (19) of the front mandrel abutment (15) is driven in the radial direction such that the front mandrel abutment (15) engages the rolling mandrel (4) holding the mandrel (8), c) feeding the first billet (1 1) to a feed clamping slide (5) and receiving the first billet (1 1) by driving the feed chuck (12) in the radial direction and clamping the first billet (1 1) by closing the feed chuck (12 ) in the radial direction on a direction of advance of the billet (1 1) front reversal point (13) of the feed tension slide (5), d) rolling out of the first billet (1 1) by the rollers (2, 3) above the rolling mandrel (4) a work hardened tube (25) by stepwise advancing the first billet (1 1) by means of the feed tension slide (5) and oscillating back and forth of the rolling mill (1) between a front (9) and a rear reversal point (10) with the rollers (2, 3),

characterized in that

before the step a) in a step a ') providing the first billet (1 1) wound on a spindle (27) and unwinding of the first billet (1 1) from the spindle (27) with an unwinding device (26) ,

A method of manufacturing a pipe according to claim 10, characterized in that the first billet (1 1) has a length of 30 m or more.

A method of producing a pipe according to claim 10 or 11, characterized by the additional step after step a) and before step b): e) driving up of a chuck (12 ') in the direction of advance of the billet (11) between the front reversal point (13 ') of a forward feed chute (5') and the front mandrel abutment (15) in the feed direction of the billet (1) in the radial direction, the rear mandrel abutment (16) of the front mandrel abutment (15) has a distance of at least 30 m, and passing through the first mandrel (1 1) by the rear mandrel abutment (16),

wherein the rolling of the first billet (1 1) by the rollers (2, 3) above the rolling mandrel (4) to a work hardened tube (25) in step c) by advancing the first billet (1 1) alternately by means of the front Feed tension slide (5 ') from a front reversal point (13') to a rear reversal point (14 ') of the front feed tension slide (5') and with the aid of a forward feed tension carriage (5) in the advancing direction of the doll from a front reversal point (14) to a rear reversal point (13) of the rear feed tension slide (5) and oscillatory back and forth movement of the roll stand (1) between a front (9) and a rear turning point (10) with the rollers (2, 3),

and wherein the method additionally comprises the steps of: f) after the complete introduction of the first billet (11) through the rear mandrel abutment (16), the chuck (20) of the rear mandrel abutment (16) is moved in the radial direction such that the rear mandrel abutment (16) engages the rolling mandrel (4). holding the mandrel (8),

g) during the rolling of the first billet (11) unwinding of a second billet (11 ') wound on a spindle (27') rotatable about an axis (28) perpendicular to the feed direction of the billet,

h) driving the chuck (19) of the front mandrel abutment (15) and passing the second billet (11 ') through the front mandrel abutment (15) into the area between the front mandrel abutment (15) and the rear mandrel abutment (16), i ) after complete passage of the second billet (11 ') through the front mandrel abutment (15), closing of the chuck (19) of the front mandrel abutment (15) such that the front mandrel abutment (15) carries the mandrel (4) 8) holds,

j) driving the chuck (20) of the rear mandrel abutment (16),

k) passing the second billet (11 ') through the rear mandrel abutment (16), I) feeding the second billet (11') to the front feed chuck (5 ') and receiving the second chunk (11') in the Feed chuck (12 ') of the front feed chute (5') and clamping the second chunk (1 1 ') by feeding the feed chuck (12') of the front feed chuck (5 ') in the radial direction,

m) ascending the feed chuck (12) of the rear feed tension slide

(5) in the radial direction,

n) incrementally advancing the second billet (11 ') alternately with the aid of the forward feed tension slide (5') and the rear feed tension slide (5) with the second billet (11 ') clamped in,

o) after the complete emergence of the first billet (1 1) finished rolled tube (25) from the rolling stand (1) introducing the second billet (1 1 ') in the roll stand (1) and

p) rolling out of the second billet (1 1 ') by the rollers (2, 3) over the rolling mandrel

(4) to a work hardened tube (25 ') by stepwise advancement of the second billet (1 1') alternately by means of the rear feed tension slide (5) and the front feed tension slide (5 ') and oscillating back and forth of the roll stand (1) between a front (9) and a rear reversal point (10) with the rollers (2, 3). A method of manufacturing a pipe according to claim 10 or 11, characterized by winding up an already finished rolled part (25) of the billet during the rolling of a part of the billet to be rolled (1 1) to a work hardened pipe (25) with the steps :

Curving an already finished rolled part (25) of the billet in a bending device (31), spirally winding an already finished rolled part (25) of the billet around a first axis (34), and

Pivoting the bending device (31) and the first axis (34) received on a holding frame (33) about a substantially perpendicular to the first axis (34) and to a longitudinal axis of a billet (11) received between the rolls (2, 3) ) parallel second axis (35) such that the pivoting at the same angular velocity as a pivoting of the billet (1 1) about its longitudinal axis during the rolling of the billet (1 1).

A method of producing a pipe according to any one of claims 10 to 13, characterized in that prior to the passage of the billet (1 1) through the front mandrel abutment (15) on a spindle (27) arranged coiled (1 1) to a temperature is heated in a range of 1000 ° C to 1200 ° C.

A method for producing a pipe according to claim 14, characterized in that before heating the billet further cold forming of the billet (1 1) takes place in a second cold pilger rolling mill such that the finished tube (25) by multiple cold forming a billet (1 1) will be produced.