RU2729480C1 - Expanded adjustment of moulding press of jco type - Google Patents

Abstract

FIELD: metal forming.SUBSTANCE: group of inventions relates to metal forming, particularly, to production of seam pipes from thick metal sheets on a pipe-forming press. Metal sheet lying on lower tool, applying bending force by means of upper tool, made with possibility of lifting and lowering, is progressively deformed into seam pipe, having longitudinal edges located opposite to each other with gap for subsequent welding of longitudinal seam. Besides, a seam pipe is made, which has a non-round shape of the rough workpiece, for which at least at one bending operation acting on the inner side of the metal sheet on the left and right respectively relative to the middle specified by the longitudinal axis of the upper tool, forming is performed. For each metal sheet, an individual contour is determined, after which using a geometrical model for the right and left side of the seam pipe, determining the angle of rotation and/or length of rotation, as well as the yield point on each side of the metal sheet. Then value of bending operation acting respectively on left and right sides on inner side of metal sheet is determined.EFFECT: accuracy of pipe geometrical dimensions is provided.7 cl, 4 dwg

Description

The present invention relates to a method for making seam pipes from metal sheets, in particular from thick metal sheets, according to which the metal sheet is fed to a pipe-forming press, in which said metal sheet lying on a lower tool by applying a bending force by means of an upper tool configured lifting and lowering, progressively deform into a seam pipe having longitudinal edges located opposite each other with a gap for subsequent welding of a longitudinal seam. In addition, the present invention relates to a device for carrying out said method.

The method used in practice for the manufacture of pipes from metal sheets is a method of forming pipes with progressive stages of forming or, respectively, bending on pipe-forming presses. As a rule, a pipe-forming or, respectively, a pipe-bending press contains in the main frame a lower tool consisting of two supporting or, respectively, bending elements located in the lateral direction next to each other at a certain distance, and an upper tool that can be installed opposite the lower the tool is mounted on a bending punch capable of lifting and lowering, and extends along the entire length of the metal sheet, and through which a bending force can be applied to the metal sheet lying on the lower tool.

The production of a pipe or pipe of a large diameter by the sequential molding process requires many consecutive working steps. In the first step, the steel sheet is pre-bent at the longitudinal edges, usually in a separate press brake. Pre-bending of the longitudinal edges is performed so that the radius of the pipe when deformed into a seam pipe in the area of the future seam - where the longitudinal edges of the steel sheet bent into the pipe lie opposite each other with a gap to weld the longitudinal seam - is formed uniformly. Then the metal sheet, previously bent in this way, is fed into a pipe-forming press, where the actual bending process is performed. In this case, as a result of pressing the upper part of the press to the metal sheet, a bending force is applied, and under the influence of the bending punch and the upper forming tool located on it, the metal sheet is deformed. This process is repeated several times until the metal sheet is deformed into a seam pipe.

DE 4215807 C2 discloses a pipe-bending or pipe-forming press in the form of a frame structure. Punson, made in the form of a bending tool, is guided vertically in the side posts of the frame. This upper bending tool is fixed to the cylinder-piston units by means of a cardan joint with low mobility and by means of these units is supported on the upper cross member of the frame. The supporting elements of the lower bending tool rest on the table, which also rests on the cylinder-piston units acting coaxially with the upper cylinder-piston units. Cylinder-piston assemblies acting against each other are designed to prevent table deflection even in case of bending of the lower frame cross member under the press working load. For this, more or less pressure is applied to the individual cylinder-piston units.

It turned out that with the progressive molding process, a big problem is a large residual joint gap of approximately 130 to 170 mm and largely dependent on the width of the punch, especially in the case of thick-walled pipes having machine thickness, for example, 40 mm, as well as stresses in the suture pipe. Large butt widths require large closing forces in a tack welder, and due to the high stresses in the tack welded pipe and residual stresses in the fully welded pipe, there is a risk of rupture of the tack seam or the weld seam. If a joint width is found that is too wide, experienced operators can close the joint as much as possible by manually activating the tube-forming press again to overcome this predicament. This method of operation not only takes a lot of time and therefore degrades performance, but also cannot be performed with reproducible good quality.

From EP 2529849 A2, a method and device are known by which a seam pipe is produced having a non-circular rough billet shape, for which at least one bending operation acting on the inner side of a metal sheet, respectively, on the left and right relative to the middle defined by the longitudinal axis of the upper tool immersed in a translationally deformable metal sheet, less deformation is carried out compared to other bending operations, and by applying a closing force that purposefully acts from the outside on a non-circular blank of a rough shape in each of the sections, previously less formed on both sides of the specified middle, a finished suture pipe. In a device for plastic deformation of a metal sheet into a non-circular billet of a rough shape, and then for plastic deformation into a suture pipe, a lower tool is provided, equipped with means made with the possibility of changing the direction of rotation of these means, and a punch made with the possibility of acting from the outside on the positioned billet of a rough shape ...

In addition, R 2543657 discloses a method of manufacturing longitudinally welded pipelines, which includes forming the main contour of a rough tube from rough rolled stock, then joining the longitudinal side edges of the deformed rough tube, welding the bridges and welding said side edges in the closed position to form a longitudinal connecting seam, and also the expansion of the manufactured pipe to maintain the outer contour, and according to which, after the outer contour of the rough pipe is formed, its subsequent shaping is carried out in at least two stages, and at the first stage from the initial position in which the gap between the lateral edges of the rough pipe is at the upper point periphery, rotate the pipe at an angle of 50 to 60 ° and fix it in this position, then a compressive load is applied in the upper region of the outer surface, evenly distributed along the length of the rough pipe, causing a vertical displacement of the specified region in the nap equalizing the axis of the rough tube by the value Δ = 0.1-0.4 S, where S is the size of the gap between the lateral edges of the rough tube, which appears after the main contour is formed, and then the load is reduced, and at the second stage of additional molding, the rough tube is rotated around axes in the opposite direction, at the same angle relative to the vertical position of the gap, as in the first stage, fix the roughing pipe in this position, and then in the upper region of the outer surface of the roughing pipe apply a compressive load evenly distributed along the entire length of the roughing pipe, causing vertical displacement of this area in the direction of the axis of the rough pipes by the same value Δ as in the first stage, and if after both stages of additional shaping of the rough pipe the clearance between the side edges is greater than the maximum value allowed for the given assortment, at least two more additional steps are performed. forming the rough tube as in the first two stages.

In practice, however, it has been found that differences in yield strength along the length of the metal sheet result in slightly different seam pipes being fed to the closing press after molding. Seam pipes have parts of larger or smaller radii, which manifests itself in the form of different joint widths. However, the radii can also be different on the left and right, which is problematic in that optimal operation of the closing press requires adjustment of parameters both from pipe to pipe and from left to right.

Therefore, the present invention is based on the task of creating a method and apparatus of the type mentioned above, which do not have the above drawbacks, in particular even in the case of thick-walled pipes and pipes with a small diameter, for example, about 800 mm, to ensure production in a simple manner and with a reproducible quality of seam pipes, having the shape of a circular cylinder.

This problem is solved thanks to the method with the features of claim 1 and the device with the features of claim 5 of the claims.

Thus, by deliberately producing a non-circular rough shape made to size, less deformed in some areas, for example, with a bend of 12 ° instead of 24 °, the most rounded geometry of the seam pipe can be formed with a minimum joint. Namely, due to the less deformed sections, a condition is created so that the closing force applied then from the outside also acts more effectively in these less deformed sections than in other sections of the pipe, and as a result, as much as possible, a circular seam pipe can be produced having the desired tight closed (compressed) gap. Unlike the case of dependence on operator experience, while maintaining the same quality, both reproducibility and productivity are improved.

Both for preforming, which is non-circular in some areas, and for final or, respectively, finishing molding, two bending operations, or, respectively, two closing (compression) processes, namely, even in the final molding by means of the closing force, may be sufficient, applied to the left and right of the gap or, respectively, the joint.

In accordance with the invention, individual parameters of rotation and pressure are determined for each individual pipe and, accordingly, for the two sides of the metal sheet to be formed. For the seam pipe, an individual contour must be defined in order to determine specific parameters for positioning the seam pipe, in particular the angle of rotation or also the length of rotation, based on the actual position of the pipe, by means of a corresponding geometric model for the left and right sides of the seam pipe. In addition, in accordance with the invention, by real-time evaluation of the displacement versus pressure curve, an inference can be made about the actual yield strength and therefore the required travel (feed) values for both the left and right sides of the metal sheet. Thus, both during positioning and when closing from pipe to pipe, as well as to the left and to the right, different parameters are used for the turns or, accordingly, the press stroke, and only in exceptional cases and with absolutely the same material yield strength throughout the metal sheet. the same parameters are used for the swivel or stroke of the press.

This requires measuring devices for determining the actual geometry, which can advantageously be located in the form of measuring robots at the end of the pipe in the closing presses. In accordance with the invention, the control must provide in real time the values calculated for the displacement and pressure in order to effect control of the stroke depending on the yield strength.

In a preferred embodiment of the invention, an even number of steps are selected in the molding press, so that, if necessary, closure can be achieved with only one closure step. For this, as is already known from the prior art, the first side must be made with reduced immersion depths in order to achieve non-roundness, but then the second side is preferably deformed like a conventional tube, in particular a round tube. Since the last stage of the second side with an even total number of stages is not in the middle of the pipe, but with lateral displacement relative to the middle of the pipe, geometric feasibility can be achieved without hitting the support pipe too hard against the deforming punch. For this, it is preferable to choose a not too small final clearance in order to avoid undesirable contact between the deforming punch and the section of the support tube.

In a further preferred embodiment of the invention, an asymmetrical preform with an even number of steps can also be produced in a JCO-type molding press, which until now could only be done with an odd number of molding steps. Thus, the last stage of plastic deformation is no longer in the middle of the seam tube, and a collision between the edges of the seam tube and the deforming punch can be prevented.

An advantage of the invention is that during the closure process each individual pipe can be responded to individually, i.e. the turns and strokes of the press are made in accordance with specific dimensions in order to achieve the most uniform result possible when plastic deforming the metal sheet into a seam pipe. Thus, in general, a better quality is achieved, since the seam pipes with a more uniform shape are fed into the tack welding machine and, accordingly, more uniform pipes are formed during the tack welding process. Differences in the contour of the seam pipe, which could arise when using rigid machine parameters, are minimized. The multiple closings known from the prior art and previously required can be avoided, so that the productivity of the device according to the invention can be increased. If an asymmetric rough blank is produced in a molding press with an even number of steps, closing can be limited to even one step if necessary.

An advantageous arrangement according to the invention provides that the non-circular blank of the rough shape is positioned by turning clockwise or counterclockwise in the final manufacturing step before applying the closing force. Thus, depending on the positioning, the closing force is applied to the non-circular blank of the rough shape next to the joint or, respectively, the gap, to the left or to the right of it.

In a preferred embodiment of the invention, the less deformed portion to the right of the middle pivots to about 3 o'clock and the less deformed portion to the left of the middle to about 9 o'clock. With this pre-positioned position of the non-circular rough blank, the maximum bending moment for the final shaping can be achieved on the support members of the lower tool.

The object on which the invention is based is achieved by the device in that there are provided means for measuring the actual geometry of the deformed metal sheet, which are connected to a control device adapted to provide real-time measured values for both the forming pressure and the amount of deformation stroke, in order to thereby be able to carry out stroke adjustment depending on the yield point.

Preferably, for plastic deformation of the metal sheet into a non-circular billet of a rough shape, and then for plastic deformation into a seam pipe, a lower tool is provided, equipped with means capable of changing their direction of rotation, and a punch configured to act from outside on the positioned billet of a rough shape.

Thus, the finished seam pipe can be produced from sheet metal only on one pipe-forming press or, respectively, a pipe-forming machine. In this case, the change in the direction of rotation makes it possible to accurately position the non-circular rough workpiece so that the closing force acts at the point of action, i.e. on both sides of the joint. In this case, the bending punch of the pipe-forming press can also be immediately used to apply the closing force to the rough mold from the outside. If necessary, the press can be re-equipped with a closing punch.

A preferred embodiment of the invention for increasing productivity provides that a closing press is installed behind at least one pipe-forming press producing a non-circular billet of a rough shape, comprising a lower tool equipped with means adapted to change the direction of their rotation, and as an upper tool containing a punch , made with the ability to act from the outside on the positioned non-circular blank of the rough shape. Thus, in the process flow behind the pipe-forming press, from which the non-circular billet of the rough shape is pushed out, a closing press is installed, in which the supplied non-circular billet of the rough shape is installed in at least two successive stages (at one stage - to the right, next to the seam or , respectively, by the gap, at another stage - to the left next to the seam or, respectively, by the gap) is plastically deformed into a finished seam pipe. Thus, the preforming of the metal sheet into a non-circular shape can be performed at a location independent of the final forming into a seam pipe.

The rotating means of the lower tool in accordance with one proposal of the invention are made in the form of two rollers located at a distance from each other, made with the possibility of bringing them into rotation. Changing the direction of rotation of the rollers allows the non-circular rough shape to be positioned for final shaping with optimized force application. Due to this chronological sequence, on the one hand during pre-forming in a tube-forming press and on the other hand during final production in a closing press, one downstream closing press can serve two tube-forming presses.

One embodiment of the invention provides that the rotating rollers are spring-suspended. The support of the non-circular rough workpiece on the lower tool of the closing press can be improved by a stationary support element provided between the rollers.

Additional features and details of the invention result from the claims and the following description of an embodiment of the invention shown in the drawings based on two separate presses. Wherein

in FIG. 1 schematically shows the manufacture of a seam pipe in accordance with the invention, by first making a sized non-circular blank of a rough shape on a conventional pipe-forming press (a), making a finished seam pipe from a non-circular blank of a rough shape in a cover press installed behind the pipe-forming press (b), and a dimensional diagram of a finished seam pipe made in accordance with the invention as shown above in FIG. 1 (c);

in FIG. 2 as a detail of FIG. 1 shows a closing press with a non-circular rough billet installed in it;

in FIG. 3A, 3B schematically show additional shaping or, respectively, plastic deformation of a non-circular blank of a rough shape from a pipe-forming press in at least two bending operations in a closing press, namely, at the first bending operation by applying a force to the non-circular blank of a rough shape on the right, next to the joint or, respectively, the gap (FIG. 3A), and in the second bending operation by applying a force to the left, next to the joint or, respectively, the gap (FIG. 3B) after turning the non-circular blank of the rough shape; and

in FIG. 4a, 4b schematically show two alternative variants of manufacturing an asymmetric blank of a rough shape by the method according to the invention, in which an even number of plastic deformation steps is used.

Plastic deformation of the metal sheet 3 into a seam pipe 104 having a significantly smaller joint or gap 111 (see FIG. 1c) is carried out on a pipe press 1 according to FIG. 1a. However, this is carried out under the condition that in one section of the metal sheet lying to the right and left of the longitudinal axis of the bending punch 7 and, therefore, near the joint or, respectively, the gap 11, the bending operation is carried out with less bending of the metal sheet than on the other bending operations. Thus, there are definitely two portions less deformed according to the bending operation, as shown in FIG. 2, so that a non-circular blank with a rough shape 13 is deliberately achieved, but sized for the final plastic deformation.

The non-circular billet of the rough shape 13, thus produced in the pipe-forming press 1 in the first stage, after being dispensed or ejected from the pipe-forming press 1, is fed into a closing press 14 installed downstream of it in the technological process and shown in FIG. 2b. The closing press 14 comprises a bottom tool 15 consisting of two spaced apart rollers 16a, 16b that can be rotated to change their direction of rotation, as shown in FIG. 2b with bidirectional arrows, and a stationary support member 17 bridging the gap between the rollers 16a, 16b. The rotating rollers 16a, 16b can be supported by resilient means 18 (see FIG. 3). Opposite the lower tool 15 is an upper tool 20 provided with a punch 19. By means of the punch 19, a closing force is applied to the non-circular blank of the rough shape 13 from the outside to produce a finished substantially circular seam tube 104.

To this end, the non-circular blank of the rough shape 13 is positioned by means of rotating rollers 16a, 16b so that the less deformed portion 12b located on the right next to the joint or gap 11, respectively, is at the 3 o'clock position, as indicated in FIG. 3 with a horizontal dash-dotted line.

The flow of this first closing bending operation is shown in FIG. 3A, which shows from left to right the positioned non-circular blank of the rough shape 13, the application of the closing force by means of the punch 19 and the punch 19 raised after the application of the force.

A second bending operation for closing is shown in FIG. 3B in the same sequence as above. To optimize the bending moment, the non-circular rough shape 13, in this case still non-circular in its left half, is positioned so that the less deformed portion 12a located on the left next to the joint or gap 11, respectively, is positioned at 9 o'clock. In this case, the closing force F (image in the center) applied by means of the punch 19 now on this side of the blank of the rough shape 13, brings the non-circular blank of the rough shape 13 into the final, substantially circular shape of the finished seam tube 104, having a significantly lower joint or, respectively, gap 111 (image on the right).

FIG. 4A and 4B show the manufacture of unsymmetrical rough blanks with an even (FIG. 4B) or odd (FIG. 4A) number of steps. FIG. 4A in 21 steps, i.e. 21 of the molding process, a so-called potato shape is formed on the side A with a bending punch 7 on the metal sheet 3, and a round half-shape on the side B. While the so-called potato shape on side A does not cause the metal sheet 3 to collide with the bending punch 7, the metal sheet 3 on the side B, on which a substantially circular shape has been made in the metal sheet 3, collides with the bending punch 7. FIG. ... 4B clearly shows the advantage of making an asymmetrical rough blank in 20 steps, i.e. in the process of an even number of stages. Neither side A, on which the so-called potato shape was made on the metal sheet 3, nor on the side B, which with the deforming punch 7 was plastically deformed into a substantially round rough billet shape, does the metal sheet 3 collide with the deforming punch 7 , since the last stage of plastic deformation occurs along the dash-and-dot line 21, therefore, with a lateral displacement relative to the middle of the pipe. As a result, a strong impact on the punch 7 of the seam pipe 4 can be prevented. Thus, the last stage of plastic deformation is no longer in the middle of the seam pipe 4, and a collision between the edges of the seam pipe 4 and the punch 7 can be prevented.

List of reference symbols

1 pipe forming press

2 hem fold

3 sheet metal

4; 104 suture tube

5a, 5b support element

6 bottom tool

7 bending punch

8 forming tool

9 top tool

10a, b counter support

eleven; 111 joint / gap

12a, b less deformed areas

13 non-round shape

14 closing press

15 bottom tool

16a, b rotating rollers

17 support element

18 elastic

19 punch

20 top tool

21 dash and dot line

Claims (28)

1. A method of manufacturing seam pipes (4; 104) from thick metal sheets (3), including feeding the sheet metal (3) to the bottom tool of the pipe-forming press (1), preliminary formation of a rough workpiece of a non-circular shape (13) by plastic deformation of the metal sheet (3) by the action of the upper tool on the inner side of the metal sheet (3), respectively, to the left and right relative to the middle specified by the longitudinal axis of the upper tool, and the final shaping of the rough billet of a non-circular shape (13) by applying a closing force that purposefully acts from the outside on the rough billet of a non-circular shape in each of the sections that were previously less deformed on both sides of the specified middle, to obtain a finished seam pipe (4; 104) with longitudinal edges located opposite each other with a gap (11; 111) for subsequent welding of a longitudinal seam, characterized in that an individual contour is determined for each deformable metal sheet, after which, using the geometric model for the right and left sides of the suture pipe, the angle of rotation and / or the length of rotation is determined as parameters for positioning the support pipe for determination by recording and evaluation in real time from the curve of the displacement versus pressure during plastic deformation of the yield strength on each side metal sheet and the magnitude of the bending force, respectively, on the left and right on the inside of the metal sheet. 2. The method according to claim 1, characterized in that the rough blank of non-circular shape (13) at the stage of final production before applying the closing force (F) is positioned by turning it clockwise or counterclockwise. 3. A device for the manufacture of seam pipes (4; 104) from thick metal sheets (3) by the method according to claim 1 or 2, containing pipe-forming press (1), equipped with a lower tool (6; 15) and an upper tool, the punch of which (9, 19) is made with the possibility of lifting and lowering for plastic deformation of a metal sheet (3) into a rough workpiece of a non-circular shape (13) and for plastic deformation of a rough workpiece of a non-circular shape (13) into a seam pipe (104), while the lower tool (15) is equipped with means made with the possibility of changing the direction of their rotation, and the punch (9, 19) is made with the possibility of acting on the inner side of the metal sheet (3) when forming a rough workpiece of a non-circular shape (13) and impacting from the outside on a positioned rough workpiece of a non-circular shape (13), characterized in that it is equipped with means for measuring the individual contour of the deformable metal sheet (3), which are connected to a control device capable of outputting real-time measured values of the bending force and the feed amount to enable adjustment of the stroke depending on the yield strength. 4. The device according to claim 3, characterized in that the control device is designed to control separately each separate operation of plastic deformation of the metal sheet (3). 5. A device according to claim 3 or 4, characterized in that that the lower tool (15) contains two rollers (16a, 16b) located at a distance from each other and made with the possibility of bringing them into rotation, and a support element (17) provided between said rollers. 6. The device according to claim 5, characterized in that that the rollers (16a, 16b) are mounted with resilient means (18). 7. A device for the manufacture of seam pipes (4; 104) from thick metal sheets (3) by the method according to claim 1 or 2, containing sequentially installed at least one pipe-forming press (1) for plastic deformation of a metal sheet (3) into a rough billet of non-circular shape (13) and a closing press (14) for plastic deformation of a rough billet of non-circular shape (13) into a finished seam pipe, while pipe-forming press (1) is equipped with the upper tool for plastic deformation of the metal sheet (3) into a rough workpiece of non-circular shape (13), which is configured to act on the inner side of the metal sheet (3) by lifting and lowering, and a lower tool (6) containing means made with the possibility of changing the direction of their rotation, and the closing press (14) is equipped with a lower tool (15) containing means made with the possibility of changing the direction of their rotation, and an upper tool (20), the punch (19) of which is configured to act from the outside on a positioned rough workpiece of a non-circular shape (13) , wherein it contains means for measuring the actual geometry of the deformed metal sheet (3), which are connected to a control device configured to output real-time measured values of the bending force and the feed amount to allow the stroke to be adjusted depending on the yield strength.

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