WO2016091530A1 - Method for producing pipes - Google Patents

Abstract

The invention relates to a method for producing pipes, wherein a sheet-metal plate (1), which is flat or is bent at at least one edge (2), undergoes at least two shaping processes, of which in the first shaping process the sheet-metal plate (1) is formed into a U shape in a U press (100) in that a punch (4) impresses the sheet-metal plate (1) in a central region, while surrounding regions lie at least partially on at least one support (5, 6) and the legs of the sheet-metal plate formed into a U shape are pressed toward each other by lateral actuators (5, 6), by means of at least one pressing surface (15, 16) in each case, and in the second shaping process the sheet-metal plate (1) formed into a U shape is converted into a pipe shape in an O press by means of half-shell tools that move toward each other. In order to improve the U forming of the sheet-metal plate, the actuators (5, 6) according to the invention press the legs (20, 21) of the sheet-metal plate (1) formed into a U shape in at least a first and a second pressing operation, which occur one after the other.

Description

 Method for producing pipes Description:

The invention relates to a method for producing pipes, wherein a flat or at least one edge bent sheet metal plate undergoes at least two forming processes, of which in the first forming process, the sheet metal plate is deformed in a U-press U-shaped by a punch the metal plate in depresses a central area while surrounding

 Areas at least partially rest on at least one carrier and lateral actuators, each with at least one pressing surface, the legs of the U-shaped sheet metal plate are pressed to each other, and in the second forming process, the U-shaped metal plate in an O-press, with each other moving Haibschalenwerkzeugen in a tube shape

is converted.

As is known, in a longitudinal tube pipes with a

Diameter of 16 "(406 mm) - 64" (1625 mm) and wall thicknesses of 6.4 mm - 38.0 mm produced.

 In longitudinal pipe production, plates made of rolled heavy plates are frequently used as base material. The basic material varies in its chemical composition as a function of wall thickness,

Pipe dimension and intended use. The physical properties or surface properties of the end product are already largely defined by the base material.

In the longitudinal tube process, the longitudinal edges of the sheets are often first prepared for the subsequent process. Here, for example, the

Chamfered edges for a later welding process or the sheets are slightly bent for easier handling in the O-press, for example. Subsequently, the sheets are deformed in the so-called U-O-E process (U-forming, O-forming, expanding).

 The U-shaped bent sheet metal is to be transported by the U-press in the longitudinal direction of the sheet in the O-press. However, it is the case that, especially in the case of thin sheets and higher strengths of the base material, today's forming process into a U-shaped profile is unsatisfactory. The sheet metal is still pressed centrally by a punch over its entire length today, while it is supported laterally. Even at maximum deformation pressure by simultaneously or subsequently acting lateral actuators, ie with a force in which the legs of the U-shaped sheet metal plate just do not buckle above the punch, but the sheet springs back on the parallel position of the legs. This means that the legs are V-shaped and the opening dimension of the U-shaped profile is too large for the diameter of the semi-circular upper tool of the O-press. D. h., The U-shaped profile of the metal plate is not to be transported in its longitudinal direction in the open O-press, when the legs of the U-shaped preformed metal plate are not at least parallel. As soon as the opening area of the legs opens in a V-shape, it is too wide to accommodate the

Haibschalenwerkzeuge the O-press to be able to drive together.

This problem is explained in part very clearly in EP1698407B1. There, it is suggested that the problem be addressed by the

Legs of the U-shaped profile on the roller table, so the transport from the U-press to the O-press further compressed. This

Method is particularly complex, because on the forcibly engagable guide rollers must also be applied in addition to a large force on the legs of the U-shaped profile. The transport routes between the two presses are so very complicated and expensive.

The object of the invention is therefore to improve the U-deformation of the metal plate. It is also the object of the invention to facilitate the transition from U to O deformation. With regard to the method, the object is achieved in that the

 Actuators in at least a first and a second pressing operation, which take place in succession, the legs of the U-shaped deformed

Press metal plate to each other.

This gives the possibility to better influence the shape of a U-shaped profile of the metal plate. Depending on the material and the thickness of the sheet metal, the pressing operations of the actuators can be carried out so that the legs of the profile of the sheet metal plate emerging from the U-press are in the desired parallelism (± 2.5 °). The plastic deformation of the metal plate is by at least a second pressing operation

the actuators much safer to achieve. As a result, the profiles are much easier to insert in the longitudinal direction in the O-press.

Preferably, the actuators and the U-shaped deformed sheet metal plate are offset relative to each other in height between the at least two pressing operations of the actuators.

 Here is an additional way to initiate the plastic deformation of the metal plate at a second location and thus to increase the effectiveness of the shaping.

It is advantageous if the U-shaped deformed metal plate is supported at its web after the first forming process by a height-adjustable support.

 Alternatively or additionally, it is of particular advantage if the U-shaped sheet metal plate at its web already during the first

 Forming process is supported by a height-adjustable support. A height-adjustable support is suitable to keep the metal plate in a defined position during the pressing operation of the actuators. In this case, the backup of the situation can be improved by the punch as an anvil again. In any case, however, it is possible to determine the height at which the actuators act on the legs of the metal sheet for shaping.

It is particularly advantageous if the U-shaped deformed metal plate at its web after the first forming process by a height-adjustable

Support is supported.

In addition, it is preferred if the height-adjustable support by

Method for the relative height difference between the actuators and the U-shaped deformed sheet metal plate provides.

 A shift of the already once U-shaped deformed metal plate is ensured by the simplified height adjustment. In this case, the U-shaped metal plate is supported with its web on the support and can be adjusted in height in such a way that a pre-determined and / or precalculated optimum height for the initiation of the forces can be adjusted and adjusted by the actuator.

Preferably, the pressing surface is defined by the peripheral surface of a

preferably rotatably arranged rotary body formed.

This ensures that the pressing surface can act on it even during the deformation of the metal plate without friction. Damage to the metal plate and the pressing surface of the actuator are thus avoided.

In a preferred manner, during the first pressing operation of the actuators, the punch remains within the U-shaped contour of the sheet metal plate and serves as an abutment surface for the legs in one region.

This is especially true if the shape of the punch head is designed to be complementary to the desired shape of the metal plate, so he sets the shape of the U-profile. As a result, too strong compression of the legs, which can lead to buckling of the web, excluded.

Advantageously, it is ensured that the stamp is removed before the second pressing operation of the actuators from the U-shaped contour of the metal plate.

In particular, if the force application of the actuators is then set much higher than in the first pressing operation, the upper edges of the sheet metal plate can be moved closer to each other because of the missing punch. As a result, even after resilience of the legs, a substantially parallel position of the legs can be achieved.

In some cases, it is advantageous if additional auxiliary actuators are used offset in height to the actuators.

 With a support of the metal plate to the auxiliary actuators, it is possible that the actuators themselves can bend the metal plate around a convex outer contour of the punch around. The number or intensity of the pressing operations of the actuators preferably takes place as a function of the thickness and / or the material of the sheet metal plate.

It is therefore possible to set the required pressures and attack heights of the actuators for different materials or plate thicknesses. The springback behavior of the metal plate is dependent on the thickness of the sheet and the material.

After a short period of experience in production or in the experiment, the necessary adjustment parameters have been determined for the deformation of the metal sheets and can be used again and again. A false production is thereby largely avoided.

It is particularly advantageous if the setting of a height difference between the actuators and the U-shaped sheet metal plate in the at least two pressing operations of the actuators by means of a control that stores a value for the applicable height difference depending on the material and the thickness of the metal plate having.

The process is almost completely automated.

The invention is explained in more detail below with reference to embodiments with reference to the drawing (s). In this shows

Figure 1 is a schematic, partially sectioned view of a

 Device for exercising the invention

 Method, Figure 2a to 2f is a schematic sequence in a stepwise

 Representation of a first embodiment of the method according to the invention and

3a to 3f, a schematic sequence in a stepwise

 Representation of a second embodiment of the method according to the invention.

The device shown in Fig. 1, also referred to as U-press 100, is intended for the bending of rectangular in plan sheet metal plates 1. These may have bent longitudinal edges 2.

In Fig. 1, a metal plate 1 has been indicated. The bending process makes of such a sheet metal blank 1 a preform having a substantially U-shaped cross-section, as required for the manufacture of large pipes. In general, it is sheet metal plates 1 of relatively thick sheets, so that high deformation forces and reaction forces are to be absorbed. The desire, however, is that even thinner sheets of higher quality, which often expand after compression, springing back to form a U-profile with parallel legs (± 2.5 °), so that the profile in

Moved longitudinally in a subsequent process step in an O-press can be inserted.

In the basic structure, the device in Figure 1 consists of a

Press frame 3, one working in a vertical bending plane

Vertical bending beam, hereinafter referred to as punch 4, and two under

Interposition of the sheet metal blank 1 to be formed in a horizontal plane against each other working Horizontal bending beam, hereinafter called actuators 5, 6. The stamp and the actuators can in the context of the invention also consist of several individual elements, for. B. a series of punches or a number of individual actuators. For some method steps, it may also be useful, not shown further

Actuators, hereinafter called auxiliary actuators, in another

additional geometric height. The actuators and the

Auxiliary actuators can communicate with each other via gears or joints.

The stamp has as a vertical bending beam at least two drives 7, 8, one at each end. This is indicated in the figure 1 only by the double numbering, because the drives are in the blade depth

behind each other. Also here are more drives in series connected single stamps possible. The drives are formed in this embodiment by cylinder-piston assemblies. There are also conceivable electrical or spindle drives here. Similarly, the actuators have actuators 9, 10, 11, 12, which are typically implemented by cylinder-piston assemblies. All drives are controlled by a common, not shown control. They act as indicated by the double arrows in two directions.

The stamp 4 presses in the production process, the metal plate 1 centrally downwards and thereby forms a web of the future U-profile. The sides of the metal plate 1 rest on carriers 17, 18, which are also formed by the actuators 5, 6 in this embodiment. The actuators each have a pressing surface 15, 16, which in the exemplary embodiment according to FIG. 1 corresponds to a circumferential surface of a rotational body, in this case a rotatable roller.

The web is formed by "dipping" the stamp 4 into the sheet-metal plate 1. It can rest on a support 22 during the pressing operation of the stamp 4 or following the pressing of the stamp 4. This support 22 is designed such that it with a

Height adjustment 23 is coupled. This height adjustment 23 includes a

Carrier 24 and other drives 27, usually piston-cylinder arrangements. The stroke of the support 22 may extend so far down that the punch 4 can be completely lifted out of the interior of the U-shaped sheet metal plate 1. To the top, the stroke should extend so far that a finished U-shaped sheet metal plate 1 in the

 Essentially horizontally out of the U-press can be removed.

The sequence of figures 2a to 2f explains in chronological order the method according to the invention in a first example. The sequence of figures 3a to 3f shows the inventive method in a second example. All figures of the two sequences are taken from a mathematical calculation model that can represent the exact bend of the sheet metal plate, and are except for the

Necessary simplifies to clarify the process better. Both process variants according to the invention would be feasible on a device according to FIG.

Therefore, Figure 2a shows only a metal plate 1 with slightly bent edges 2. This metal plate lies on supports 17, 18, which occupy the function of the actuators 5, 6 later. Above the stamp 4 starts with the

Stamp head 13 to press on the metal plate. The force is initiated by the drives 7, 8, not shown on the punch neck.

Figure 2b shows a later stage. The metal plate is U-shaped deformed and is now supported by the web 19 on the support 22 from. The legs 20, 21 are compressed via the actuators. The indicated

Force arrows show that the metal plate is pressed on both sides of the punch head 13 until the plate edges abut the punch neck.

In Figure 2c we learn that despite the previous

Squeezing the thighs up to the punch neck, these spread apart after removing the actuators back springing too far, as that they could retract into an O-press. The desired U-shape of the metal plate, with a leg parallelism of ± 2.5 °, is not yet reached. Rather, one speaks here of a V-shape.

Therefore, as shown in Figure 2d, the punch removed from the inner contour of the metal plate.

According to Figure 2e, the actuators are active again. In this second

But pressing the leg can be brought together a little closer because both punch head and punch neck were removed.

As a result, results after the withdrawal of the actuators, a uniform U-profile with parallel legs This can on the

height-adjustable support can be lifted up to the side

can be transported away.

A variant of the method according to the invention, the figures 3a to 3f in time sequence.

Since you want to deform a particularly thin sheet of high-quality steel, which has a particularly strong springback, the process is to the already known components even more

Auxiliary actuators 25, 26 supported.

The process begins as in the first example with a first pressing operation, so that the figures 3b and 3c substantially the figures 2b and 2c

correspond. From Figure 3c, the process is different from the first

 Embodiment. The height-adjustable support 22 is namely lowered, while the punch 4 and also the actuators maintain their position. Thus, a relative height offset between the sheet metal plate and actuators occurs between the first and the subsequent second pressing operation of the actuators.

The actuators and the auxiliary actuators become the legs

subsequently - shown in Figure 3e - clearly closer to the leg ends attacking the second time pressed the punch head. So that the sheet does not buckle, the auxiliary actuators support the process by supporting the sheet deeper than the actuators.

As a result (Figure 3f) is again obtained an ideal U-shaped contour of the metal plate, which is suitable for further processing in an O-press.

The relative height offset between the metal plate and actuators is deposited in dependence on the plate thickness and their material in a controller, not shown, and preferably approached automatically. Decisive for a better deformability is therefore in both

Embodiments of the staggered second pressing operation of

Actuators, after springback of the metal plate from the first

Pressing process is initiated. It is particularly advantageous if the actuators at the two pressing operations at different

Attack leg positions.

LIST OF REFERENCE NUMBERS

 1 sheet metal plate

 2 Rounded edge

 3 press frame

4 stamps

 5 actuator

 6 actuator

 7 punch drive

8 punch drive

9 actuator drive

10 actuator drive

1 1 actuator drive

12 actuator drive

13 stamp head

 14 stamp neck

 15 pressing area

 16 pressing surface

 17 carriers

 18 carriers

 19 footbridge

 20 thighs 1

 21 thighs 2

 22 support

 23 Height adjustment of the support

24 carriers of the height adjustment

25 auxiliary actuator

 26 auxiliary actuator

 27 Drive of height adjustment 100 U-press

Claims

claims: Method for producing pipes, wherein a flat sheet metal plate (1) bent on at least one edge (2) passes through at least two forming processes, of which in the first forming process, the sheet metal plate (1) in a U-press (100) is U-shaped deformed by a punch (4) presses the metal plate (1) in a central region, while surrounding areas at least partially on at least one carrier (5, 6) rest and lateral actuators (5, 6), each with at least one pressing surface (15, 16), the legs of the U-shaped deformed metal plate are pressed to each other, and in the second forming process, the U-shaped sheet metal plate (1) is converted into a tube shape in an O-press, with mutually moving sheath-shell tools, characterized in that the actuators (5, 6) in at least a first and a second pressing operation, which take place one behind the other, the legs (20, 21) of the U-shaped deformed sheet metal plate (1) to each other press. A method according to claim 1, characterized in that between the at least two pressing operations of the actuators, the actuators and the U-shaped deformed metal plate are offset relative to each other in height. A method according to claim 1 or 2, characterized in that, the U-shaped sheet metal plate at its web after the first Forming process is supported by a height-adjustable support. 4. The method according to any one of claims 1 to 3, characterized in that the U-shaped deformed metal plate (1) is supported at its web (19) during the first forming process by a height-adjustable support (22). 5. The method according to claim 3 or 4, characterized in that the height-adjustable support (22) by processes for the relative height difference between the actuators (5, 6) and the U-shaped deformed metal plate (1). 6. The method according to any one of claims 1 to 5, characterized in that the pressing surface (15, 16) through the peripheral surface of a  preferably rotatably arranged rotary body is formed. 7. The method according to any one of claims 1 to 6, characterized in that the punch (4) during the first pressing operation of the actuators (5, 6) within the U-shaped contour of the metal plate (1) remains and in an area as a stop surface for the legs (20, 21) is used. 8. The method according to any one of claims 1 to 7, characterized in that the punch (4) before the second pressing operation of the actuators (5, 6) from the U-shaped contour of the metal plate (1) is removed. 9. The method according to any one of claims 1 to 7, characterized in that height offset from the actuators (5, 6) further auxiliary actuators (25, 26) are used. 10. The method according to any one of claims 1 to 9, characterized in that the number or intensity of the pressing operations of the actuators (5, 6) in dependence on the thickness and / or the material of the sheet metal plate (1). Method according to one of claims 2 to 10, characterized in that the adjustment of a height difference between the actuators (5, 6) and the U-shaped sheet metal plate (1) in the at least two pressing operations of the actuators (5, 6) by means of a controller takes place, which stores a value for the height difference to be applied  Has dependence on the material and the thickness of the metal plate (1).