DE102009034541B3 - Method and apparatus for stretch forging of twisted parts - Google Patents

Abstract

Method for stretch forging workpieces with the following steps: a) Carrying out a relative movement of a heated and / or flowable metallic workpiece (2) in a stretching direction (V) relative to at least two stretching tools (4A, 4B) by means of at least one gripping device ( 3), b) Rotating the workpiece (2) by means of the gripping device (s) (3) with respect to an axis (A) axially to the stretching direction (V) and / or an axis (A) preferably running through the workpiece (2) by a predetermined angle of rotation (α1), wherein the movements of steps a) and b) can be carried out in any order one after the other or also simultaneously, c) supporting the workpiece (2) in a partial area (22 ', 25') by at least one support element (5A , 5B) a torque support device (5) is brought into abutment with this sub-area (21 ', 24') of the workpiece (2) in a flat or form-fitting manner, d) forming a further sub-area (23, 26) of the workpiece ( 2), which is offset axially to the axis (A) and / or against the stretching direction (V) in relation to the supported partial area (21 ', 24'), in a forming step by moving at least one of the stretching tools (4A, 4B) towards the workpiece (2 ), wherein the at least one support element (5A, 5B) at least partially supports or absorbs a torque exerted on the supported partial area (21 ', 24') during this forming of the further sub-area (23, 26) and thereby a torque load on the .. .

Description

The invention relates to a method and a device for stretch-forging workpieces.

Forging is a hot forming of metallic malleable materials, especially metallic alloys such as steels. Stretch forging, also referred to as stretch forging or in short as stretching, is a method for open-die forging in which in each case only a small part of the workpiece volume is formed between two stretching tools (or drawers) in successive forging steps. During the stretch forging, the workpiece is usually held at one end or at both ends by gripper tongs of manipulators or robots and moved in a stretching direction between the stretching tools in individual steps and then compressed in opposite to the stretching direction successive portions of the stretching tools perpendicular to the stretching direction. The material of the workpiece flows parallel to the stretching direction, so the workpiece is in the cross section perpendicular to the stretching direction thinner and parallel to the stretching direction longer. The stretching tools tend to have crowned or convex curved surfaces and are also referred to as stretch or saddle saddles, the upper saddle being called the upper saddle and the lower saddle the lower saddle. As a result of the successive individual forming processes or "bites", a wavy structure which images the shape of the saddles remains with grooves on the workpiece. The surface of the workpiece is therefore often smoothed in a subsequent operation with smoothing tools, which usually have a larger dimension than the stretching tools. Most of the upper saddle is arranged on a movable upper tool carrier or bear and the lower saddle on a generally immovable lower tool carrier, the Schabotte. But it is also possible that both stretching tools move. As forming machines when stretching usually forging presses or forging hammers are used, where then the stretching tools are provided. To forge back a widening usually unwanted when stretching the workpiece, the forging can be turned by 90 ° after each blow. Stretch forging or stretching is often used as preforming or for material pre-distribution prior to die forging, in which the workpiece is brought to its final shape (for this general state of the art see, for example, Herbert Fritz and Günter Schulze, "vdi-Fertigungstechnik", Springer -Verlag, 5th edition, 2001, pages 402-405).

Typically, rod-shaped or cuboidal blanks are elongated axially during stretch forging and possibly already provided with contours when seen in a longitudinal section in the stretching direction. A twisted or twisted shape of the workpiece can not be produced with such a stretch-forging process according to the prior art.

However, it would be desirable to have preforming of a blank into a preform which is more closely approximated to the final shape for subsequent die-forging in order to produce machined workpieces such as turbine blades, preferably further employing a stretch forge or modified stretch forging.

Out DE 203 11 306 U1 a device for forging a workpiece with handling by two industrial robots is known.

The EP 1 600 227 B1 discloses an apparatus for forging a workpiece, in which synchronously intermittently driven from both ends, wherein an additional drive of the counter-holder, a torsional stress of the workpiece is reduced.

Out GB 840,635 is an apparatus for forging axles or profiled shanks known with two synchronized forging tools and two rotary drives for driving the forging tools.

The invention is therefore, on the basis of the aforementioned object, the object of developing a method for stretch-forging of workpieces and a device for stretch-forging of workpieces so that even twisted workpieces can be produced.

This object is achieved according to the invention by a method having the features of patent claim 1 and by a device having the features of claim 11. Advantageous embodiments and further developments will become apparent from the dependent claims 1 and 11 respectively dependent claims.

• a) Durchführen einer Relativbewegung eines erwärmten und/oder in einem fließfähigen Zustand befindlichen metallischen Werkstückes in einer Reckrichtung relativ zu wenigstens zwei Reckwerkzeugen mittels wenigstens einer Greifeinrichtung,
• b) Drehen des Werkstücks mittels der Greifeinrichtung(en) bezüglich einer axial zur Reckrichtung und/oder einer, vorzugsweise durch das Werkstück verlaufenden, Achse um einen vorgegebenen Drehwinkel, wobei die Bewegungen der Schritte a) und b) in beliebiger Reihenfolge nacheinander oder auch gleichzeitig durchgeführt werden können,
• c) Abstützen des Werkstücks in einem Teilbereich, indem wenigstens ein Stützelement einer Drehmomentabstützeinrichtung mit diesem Teilbereich des Werkstücks flächig oder formschlüssig in Anlage gebracht wird,
• d) Umformen eines weiteren Teilbereiches des Werkstücks, der zum abgestützten Teilbereich axial zur Achse und/oder entgegen der Reckrichtung versetzt ist, in einem Umformschritt durch Zustellen wenigstens eines der Reckwerkzeuge zum Werkstück, wobei das wenigstens eine Stützelement ein bei diesem Umformen des weiteren Teilbereichs auf den abgestützten Teilbereich ausgeübtes Drehmoment wenigstens teilweise abstützt oder aufnimmt und dadurch eine Drehmomentbelastung auf die Greifeinrichtung und/oder auf einen zwischen dem wenigstens einen Stützelement und der Greifeinrichtung liegenden Bereich des Werkstücks reduziert oder verhindert,
• e) Rückholen des oder der zugestellten Reckwerkzeuge(s) sowie vorzugsweise auch des oder jedes Stützelementes vom Werkstück.

The method according to claim 1 is provided for the stretch-forging of workpieces and comprises the following method steps, which are carried out at least once, preferably in a plurality of successions:

• a) performing a relative movement of a heated and / or in a flowable state metallic workpiece in a stretching direction relative to at least two stretching tools by means of at least one gripping device,
• b) rotating the workpiece by means of the gripping device (s) with respect to an axis extending axially to the stretching direction and / or an axis, preferably through the workpiece by a predetermined angle of rotation, wherein the movements of steps a) and b) in any order sequentially or simultaneously can be performed
• c) supporting the workpiece in a partial area by at least one support element of a torque support device being brought into contact with this partial area of the workpiece in a planar or form-fitting manner,
• d) forming a further portion of the workpiece, which is offset to the supported portion axially to the axis and / or opposite to the stretching direction, in a forming step by feeding at least one of the stretching tools to the workpiece, wherein the at least one support element in this forming the further portion on at least partially supports or absorbs the torque exerted on the supported partial region and thereby reduces or prevents a torque load on the gripping device and / or on a region of the workpiece lying between the at least one supporting element and the gripping device,
• e) retrieving the or the delivered stretching tools (s) and preferably also of the or each support element from the workpiece.

• a) eine Reckeinrichtung mit wenigstens zwei Reckwerkzeugen,
• b) wenigstens eine Greifeinrichtung zum Greifen eines Werkstücks, Durchführen einer Relativbewegung des Werkstückes in einer Reckrichtung relativ zu den wenigstens zwei Reckwerkzeugen und Drehen des Werkstücks bezüglich einer axial zur Reckrichtung und/oder einer, vorzugsweise durch das Werkstück verlaufenden, Achse um einen vorgegebenen Drehwinkel,
• c) eine Drehmomentabstützeinrichtung zum Abstützen des Werkstücks in einem Teilbereich mit wenigstens einem Stützelement, das mit diesem Teilbereich des Werkstücks flächig oder formschlüssig in Anlage bringbar oder gebracht ist und bei Umformen eines weiteren Teilbereiches des Werkstücks, der zum abgestützten Teilbereich axial zur Achse und/oder entgegen der Reckrichtung versetzt ist, in einem Umformschritt durch Zustellen wenigstens eines der Reckwerkzeuge zum Werkstück ein bei diesem Umformen des weiteren Teilbereichs auf den abgestützten Teilbereich ausgeübtes Drehmoment wenigstens teilweise abstützt oder aufnimmt und dadurch eine Drehmomentbelastung auf die Greifeinrichtung und/oder auf einen zwischen dem wenigstens einen Stützelement und der Greifeinrichtung liegenden Bereich des Werkstücks reduziert oder verhindert.

The device according to claim 11 is suitable for stretch-forging heated and / or in a flowable state metallic workpieces suitable and intended and in particular provided for carrying out a method according to the invention and comprises

• a) a stretching device with at least two stretching tools,
• b) at least one gripping device for gripping a workpiece, performing a relative movement of the workpiece in a stretching direction relative to the at least two stretching tools and rotating the workpiece with respect to an axis extending axially to the stretching direction and / or an axis extending preferably through the workpiece by a predetermined angle of rotation,
• c) a torque support device for supporting the workpiece in a partial area with at least one support element which can be brought or brought into abutment with this portion of the workpiece surface and form fit and in forming a further portion of the workpiece to the supported portion axially to the axis and / or offset in a forming step by delivering at least one of the stretching tools to the workpiece at least partially supports or absorbs a torque exerted on the supported portion in this forming of the further portion and thereby a torque load on the gripping device and / or one between the at least a support element and the gripping device lying region of the workpiece is reduced or prevented.

The relative movement of two components, such. As the stretching tools and the workpiece in the stretching direction to each other means here and according to general understanding that either any of the two components fixed to an external coordinate system (or reference system), z. As a machine frame, and the other is moved relative to or in the outer coordinate system or that both components are moved relative to the outer coordinate system in a resultant counter-movement.

In a preferred embodiment, the relative movement between the workpiece and the stretching tools is a translation movement axially relative to the axis and / or takes place in the stretching direction about a predetermined axial path axially to the axis. The predetermined axial path for several or all relative movements between the workpiece and stretching tools is preferably constant, but may also vary.

The axial travel is preferably smaller than an axial dimension of the stretching tools, in particular chosen between one third and two thirds of the axial dimension of the stretching tools. As a result, it can be achieved, in particular in a further embodiment, that at least two of the partial regions of the workpiece to be reshaped or formed overlap partially axially with respect to the stretching direction and / or axis.

The rotation angle at each rotation of the workpiece or differential rotation angle between two rotation angles of successive rotation steps is selected according to the desired twist of the workpiece and thus selected constant or variable, in particular from a range between 0.5 ° and 15 °, in particular between 1 ° and 5 ° ,

The supported partial region of the workpiece is preferably a partial region of the workpiece which has already been formed in an earlier forming step.

In a further embodiment, at least one further already formed partial area lies between the supported partial area and the further partial area formed or to be formed by means of the stretching tools.

In a further embodiment, the workpiece of one or two gripping devices in each one assigned, preferably at one Gripping area located at the end of the workpiece and, during the relative movement and / or the rotational movement, held in a position aligned along the axis, which is preferably a substantially horizontal position.

The advancing movement and return movement of the stretching tool or tools and / or of the supporting element (s) takes place in particular vertically and / or perpendicular to the stretching direction and / or to the axis.

The stretching tools generally have mutually facing in the axial direction convex curved or spherical forming surfaces, which are reflected in the workpiece when pressed or hitting as a complementary concave contour.

The at least one support element now preferably has a support surface which is convexly curved in the axial direction and which is adapted to the convexly curved forming surfaces of the stretching elements and thus the concave contour of the formed surface of the workpiece in the mold, and / or substantially over a large area over its axial surface entire axial length can be supported on the workpiece.

The support surface should also be extensively supported on the workpiece in one or each cross-sectional plane perpendicular to the axial direction or to the axis. In one embodiment, the support surface in this cross-sectional plane is essentially inclined by a tilt angle corresponding to the angle of rotation or the difference in rotational angle of the previously or just made rotational movement of the workpiece, in particular with respect to the axis or horizontal, so that the support elements do not have to be rotated. But it is also possible to rotate the support elements adapted to the movement of the gripping device or the workpiece.

The axial length of the or the support elements (s) or its support surface is preferably chosen smaller than the axial length of the stretching elements or their forming surfaces in order to arrange the support elements axially as close to the stretching elements can.

In a preferred variant, prior to the first forming step and / or in the gripping region, the workpiece has a polygonal, in particular rectangular, preferably square, or round, in particular circular, cross section perpendicular to the axis.

The stretching device is or generally comprises a work-bound or bound forming machine, preferably a forging hammer or a forging press, d. H. their stretching tools work either as presses or tied away, or beating or work-bound.

The invention will be explained below with reference to exemplary embodiments. Reference is also made to the drawings, in whose

1 a forging device with a parallelepiped blank before the first forming step in a partially sectioned longitudinal view,

2 the forging device according to 1 in a partially sectioned front view,

3 the forging device according to 1 and 2 in the first forming step in a partially sectioned longitudinal view,

4 the forging device according to 3 in a partially sectioned front view,

5 the forging device according to 1 to 4 before a third forming step with a workpiece rotated by an angle of rotation and with torque support elements engaging in the partial area formed during the first forming step, in a partially sectioned longitudinal view,

6 the forging device according to 5 in a partially sectioned front view,

7 the forging device according to 5 and 6 in the following third forming step with stretching tools pressing into the workpiece,

8th the forging device according to 7 in a partially sectioned front view,

9 the forging device according to 1 to 8th during a sixth forming step with supporting torque support elements in a partially sectioned longitudinal view and

10 the forging device according to 9 in a partially sectioned front view
are each shown schematically. Corresponding parts and sizes are in the 1 to 10 provided with the same reference numerals.

The 1 to 10 show a device for stretch-forging or stretching a first present in the form of a, for example, straight parallelepiped, blank metal workpiece in a twisted, preformed workpiece in different states or process stages. At the same time illustrate the 1 to 10 also a corresponding stretch forging process.

The workpiece is always with you even in the deformed states 2 designated. The blank of the workpiece 2 After it has been heated in an oven for hot forming and thereby brought into a flowable state according to 1 and 2 from a gripping device 3 in one at one end of the workpiece 2 located gripping area 20 gripped and held in a aligned along an axis A position, which is a substantially horizontal position in the illustrated embodiments. The axis A runs longitudinally and centrally through the workpiece 2 , Usually, at the other end of the workpiece 2 provided a further gripping device, which is not shown. If the workpiece 2 however, is relatively short, can also be a single gripping device 3 on only one side of the workpiece 2 suffice.

The at least one gripping device 3 not only keeps the workpiece 2 in the corresponding position along the axis A, but can the workpiece 2 also move in a stretching direction V axially or linearly to the axis A and at the same time the workpiece 2 also rotate about its axis A in a rotational movement D. The angle of rotation to the horizontal is denoted by α.

There are also two stretching tools located above and below the horizontal axis A. 4A and 4B a stretching device 4 provided in a direction perpendicular to the stretching direction V or axis A directed stretching movement R on the workpiece 2 are movable and to reshape the workpiece 2 act on this striking or pressing and after such a forming step again in a return movement from the workpiece 2 out or back are movable. There can only be one or both tools 4A and 4B to be moved. Furthermore, more than two stretching tools can be provided. The stretching movement R does not have to be vertical, but can also be horizontal, for example.

The stretching device 4 also includes an unillustrated, but known drive means for driving the stretching tool or tools (s) 4A and 4B for the stretching movement R and the return movement and possibly corresponding guides. In particular, the stretching device 4 be formed on or with a work-bound or weggebundenen forming machine, preferably with a forging hammer, in particular Oberhammer or counter-impact hammer, or a forging press.

The stretching tools 4A and 4B have axially seen to the axis A an axial length B, which is selected depending on the desired deformation and also depending on the available pressing force or forming energy.

Furthermore, the stretching tools 4A and 4B facing convexly curved or spherical forming surfaces 41 and 42 on, which is in the workpiece 2 when impressed or impact as a complementary concave axial contour map, and are therefore often referred to as saddle saddle.

The illustrated gripping device 3 grips the workpiece 2 by means of two opposing gripping elements 3A and 3B , The gripping angle of the gripping elements 3A and 3B between a common gripping axis G of the two gripping elements 3A and 3B passing through the two gripping elements 3A and 3B as well as through the workpiece 2 runs, on the one hand and the horizontal on the other hand, is denoted by β and in 2 for example, equal to 45 °.

The workpiece 2 has in the illustrated embodiments in the original state as a blank according to 1 and 2 a continuous square cross-section perpendicular to the axis A, that is formed cuboid with a square base.

In the grip area 20 in which the stretching tools 4A and 4B do not intervene over the entire forming process, the workpiece cross-section is maintained, here so the square cross-section. Each gripping element has been adapted to this square workpiece cross-section 3A and 3B in each case two gripper fingers or gripper tongs, which are aligned at 90 ° to each other and each have an intermediate piece on one side of the workpiece 2 attack. As a result, the gripping fingers of the gripping elements 3A and 3B each on one side of the square cross section and the workpiece 2 is in the grip area 20 in which the stretching tools 4A and 4B over the entire forming process do not intervene, form-fitting between the two gripping elements 3A and 3B held like a square in a wrench. For another workpiece cross-section in the grip area 20 also becomes the shape of the gripping elements 3A and 3B adjusted accordingly.

In 1 and 2 is one in the intermediate gap between the two stretching tools 4A and 4B lying part of the workpiece 2 With 21 indicated and indicated by dashed lines. The gripping device 3 is relative to the stretching tools 4A and 4B at rest and the stretching tools 4A and 4B shape the workpiece 2 not yet around. Of the axial distance of the stretching tools 4A and 4B from the gripping device 3 is in 1 denoted by e.

Furthermore, in 1 and 2 two support elements 5A and 5B a Drehmomentabstützeinrichtung 5 seen in a rest position axially approximately in the region of the gripping elements 3A and 3B and their function will be explained later. The axial distance of the stretching tools 4A and 4B from the support elements 5A and 5B is in 1 . 3 . 5 and 7 denoted by d and preferably remains the same, but can also change, in particular become larger, to compensate for any elongations.

In the next stage according to 3 and 4 now become the stretching tools 4A and 4B in the stretching movement R in the sub-area 21 of the workpiece 2 pressed in a first forming step and stretch the workpiece 2 , The reshaped section 21 ' now has the axial length B1, in the illustrated first forming step usually the entire axial length B of the stretching tools 4A and 4B equivalent. The workpiece 2 now has due to this stretching process by means of stretching tools 4A and 4B a cross-sectionally approximately rectangular shape in the partial area 21 ' with a smaller height in the direction of the stretching movement R, but a greater width perpendicular thereto. The cross section changes axially relative to the axis A according to that of the forming surfaces of the stretching tools 4A and 4B embossed or imaged shape. In a typical for a stretching or stretching forging way so the workpiece 2 in the subarea 21 respectively. 21 ' compressed and widened in cross section and also, especially against the stretching direction V, lengthened. Due to the elongation of the workpiece 2 now has the gripping device 3 from the stretching tools 4A and 4B a greater axial distance e '> e.

The stretching tools 4A and 4B will now be in the return movement from the workpiece 2 extended so that this between the stretching tools 4A and 4B can be moved axially further. Now, in an intermediate step, not shown, and still without rotation of the workpiece 2 , the workpiece 2 in the stretching direction V about an axial distance .DELTA.x from the gripping device 3 moved linearly and the stretching tools 4A and 4B engage in a second forming step again in a second portion 22 of the workpiece 2 , which directly adjoins the first, now reshaped section 21 ' connects, one.

The axial travel .DELTA.x can in particular also be smaller than the length B of the stretching tools 4A and 4B , For example, about half the axial length B / 2 of the two stretching tools 4A and 4B correspond.

This causes the stretching tools 4A and 4B in the second forming step also overlapping a part of the already reshaped portion 21 ' further reshape and turn a complementary their forming surfaces concave contour in the longitudinal direction or axial direction of the workpiece in the now transformed second portion 22 ' leave behind. As the penetration depth or forming depth of the stretching tools 4A and 4B In the second forming step is usually chosen as well as in the first forming step, a wavy or grooved structure with an axial contour with two concave troughs, which meet in a peak, emerged.

Now the stretching tools 4A and 4B moved back again and the workpiece 2 in turn, is an axial path, preferably the same axial path .DELTA.x, in the stretching direction V of the gripping device 3 moved linearly in translation.

However, before, after or during this axial displacement movement about the distance Δx along the axis A, the workpiece now becomes 2 from the gripping device 3 additionally rotated by a rotation angle α = α1. This rotation serves to the workpiece 2 to give the desired spin.

The result of the intermediate step described as well as the subsequent displacement and rotational movement about α1 is in 5 and 6 shown. The angle of rotation α is measured counterclockwise with respect to the horizontal, so it was at 1 to 4 α = 0 ° and is now in 5 and 6 α = α1. The gripping angle β decreases accordingly by the rotation angle α1. In the illustrated embodiments, the gripping axis G is directed so that β = 45 ° - α applies.

For the sequence of the rotational angle values in the individual rotational steps αi + 1 = αi + Δα with i ≥ 0 and the differential angle Δα, which depends on the desired twist of the finished workpiece 2 is selected, and is typically between 0.5 ° and 15 °, for example between 1 ° and 5 °, when 360 ° corresponds to one complete revolution.

In the illustrated embodiments, the change or increase in the angle of rotation α per rotation or rotation step of the workpiece 2 equal or constant, ie the difference angle Δα is a constant. This leads to a constant twist of the workpiece 2 , In the illustrated embodiments, Δα = 5 ° and thus α0 = 0 ° and α1 = 5 °, α2 = 10 °, α3 = 15 ° and α4 = 20 °.

However, it is also possible to make the rotational angle change Δα variable, for example increasing or decreasing and / or even not only positive, but also negative (ie reversal of the direction of rotation), if a variable twist in the workpiece 2 wants to produce.

The axial distance d of the stretching tools 4A and 4B from the support elements 5A and 5B is in the position according to 5 stayed the same 1 and 3 because there is no axial relative movement between stretching elements and support elements is provided, which is not excluded in principle.

By impressing or hitting the stretching tools 4A and 4B , what in 7 and 8th is shown, and the deformation forces caused thereby now arises due to the rotated position of the workpiece 2 a torque, which also includes a torsional moment, on the workpiece 2 that extends to the handle area 20 of the workpiece 2 in the gripping device 3 is held, propagates and on the one hand to an undesirable recovery in the already reshaped part 21 ' could lead, on the other hand and especially to an undesirable force on the gripping device 3 leads.

To intercept or support this torque is the already mentioned Drehmomentabstützeinrichtung 5 provided that works as follows.

In the already reshaped subarea 21 ' of the rotated workpiece 2 take action now 5 and 6 and 7 and 8th in addition, on opposite sides, in particular as shown from above and below, the two support elements 5A and 5B the Drehmomentabstützeinrichtung 5 one. The support elements 5A and 5B have convex curved support surfaces 51 and 52 attached to the convexly curved forming surfaces 41 and 42 the stretching elements 4A and 4B are adapted in shape so that the support elements 5A and 5B axially with their support surfaces 51 and 52 over a large area over its entire axial length C on the workpiece 2 can support. The axial lengths C of the support elements 5A and 5B is chosen slightly smaller than the axial length B of the stretching elements 4A and 4B , so that the support elements 5A and 5B as early as possible or close to the stretching elements 4A you 4B can be retracted.

Around the support surfaces 51 and 52 also in one or each of the axial direction or the axis A perpendicular cross-sectional plane according to 6 and 8th large area on the workpiece 2 to be able to support, as in 6 and 8th to recognize the support surfaces 51 and 52 in the cross-sectional plane substantially inclined by the differential rotation angle Δα to the horizontal and thus in the cross-sectional plane approximately parallel to the opposite upper and lower surfaces of the portion 21 ' or the upper and lower sides of the workpiece cross section in the partial area 21 ' because of this subarea 21 ' has also been rotated by the differential rotational angle .DELTA..alpha. and thus its sides are inclined to the horizontal by this differential rotational angle .DELTA..alpha. The completed rotational movement of the workpiece 2 by the angle of rotation Δα after the deformation of the second portion 22 respectively. 22 ' So it is with the inclined support surfaces 51 and 52 balanced when the angle of inclination of the support surfaces 51 and 52 On the one hand and the rotation angle of the supported portion on the other hand coincide. The advantage of these inclined support surfaces is the simple linear feed or retraction and extension movement of the support elements 5A and 5B to the workpiece 2 towards or away from it, without the support elements 5A and 5B with the workpiece 2 have to turn.

But it is also possible, the support elements 5A and 5B and their support surfaces 51 and 52 the rotation of the workpiece 2 to let follow or in each case to turn the angle of rotation, for example by the support elements 5A and 5B together with the gripping device 3 rotates or tunes the respective drives according to each other or synchronized. Although this embodiment is somewhat more expensive, but has advantages especially with variable rotation angle difference .DELTA..alpha. And / or when the number of lying between the portion to be reshaped and the supported portion lying portions should be changed, and can with non-inclined support surfaces as well as again with inclined support surfaces 51 and 52 be combined.

Thus, the workpiece is 2 as in 5 and 6 such as 7 and 8th to see from the two support elements 5A and 5B the support device 5 supported positively on two opposite sides. This causes both the workpiece 2 in between the support elements 5A and 5B and the gripping device 3 lying and / or already reshaped areas and the gripping device 3 against the intervention of the stretching tools 4A and 4B In the subsequent forming step acting torques, which are counted here also torsional moments, secured, because these torques are from the support elements 5A and 5B taken or supported.

After the forming step according to 7 and 8th become the stretching tools 4A and 4B again in the return movement of the workpiece 2 removed and also the support elements 5A and 5B the Drehmomentabstützeinrichtung 5 again from the workpiece 2 far enough away that there is a sufficient gap between both the stretching tools 4A and 4B as well as between the support elements 5A and 5B is generated, through which the workpiece 2 from the gripping device 3 pulled through or can be passed through.

• • axiales Verschieben des Werkstücks 2 um den axialen Weg Δx,
• • Drehung des Werkstücks um den Drehwinkel Δα
• • Abstützen des Werkstücks 2 in einem bereits umgeformten Teilbereich durch Einfahren oder Zustellen der Stützelemente) 5A und 5B der Drehmomentabstützeinrichtung 5
• • Umformen des Werkstücks 2 in einem von dem abgestützten Teilbereich beabstandeten, weiter von der Greifeinrichtung 3 weg liegenden weiteren Teilbereich durch Zustellen der Reckwerkzeuge 4A und 4B,
• • Rückholen von Reckwerkzeugen 4A und 4B und Stützelementen 5A und 5B

bis das Werkstück 2 über die vorgesehene axiale Länge gereckt und gleichzeitig gedrallt worden ist.Now the sequence of the following steps is repeated

• • axial movement of the workpiece 2 around the axial path Δx,
• • Rotation of the workpiece by the angle of rotation Δα
• • supporting the workpiece 2 in an already transformed partial area by retracting or delivering the support elements) 5A and 5B the Drehmomentabstützeinrichtung 5
• • Forming the workpiece 2 spaced apart from the supported portion, farther from the gripping device 3 weg lying further portion by delivering the stretching tools 4A and 4B .
• • Return of stretching tools 4A and 4B and support elements 5A and 5B

until the workpiece 2 Stretched over the intended axial length and has been twisted at the same time.

The 9 and 10 show a state where already three more sub-areas 23 ' . 24 ' and 25 ' of the workpiece 2 were reshaped accordingly. These subareas 23 ' to 25 ' are again each rotated by the rotation angle .DELTA..alpha. In 9 and 10 is a rotation angle α = α4 = 4 Δα reached, so that with Δα = 5 ° applies α4 = 20 ° and β = 25 °. The support elements 5A and 5B the Drehmomentabstützeinrichtung support the sub-area 24 ' down while the stretching tools 4A and 4B just the subarea 26 of the workpiece to be transformed by the partial area 25 ' from the supported section 24 ' is spaced.

In this way, therefore, the entire workpiece is formed piece by piece or step by step in mutually rotated by the rotation angle portions until the end of the area to be formed is reached. The workpiece produced thereby has a twisted basic shape and can be ready forged as a preformed part in a subsequent drop forging operation to a twisted finished part, such as a turbine blade.

The support of the workpiece 2 through the support elements 5A and 5B can take place in a previously formed partial area, which either directly adjoins the partially formed partial area or is spaced therefrom by one or more already formed partial areas, by a sufficient distance between the supporting elements 5A and 5B on the one hand and the stretching tools 4A and 4B on the other hand.

Preferably, an intermediate switching of a reshaped partial region, as shown in the FIG, between the currently formed portion and the thereby supported portion, because in this case the support is close enough to the deformation point and the freedom of movement of the tools is still guaranteed. This is achieved in the illustrated embodiment by the two first forming steps according to 1 to 4 without rotation, where the first intermediate section 22 ' is generated, which then continues successively, and by the inclination of the support surfaces 51 and 52 the support elements 5A and 5B around the angle of rotation Δα. It can also be provided more than two support elements or even a single corresponding to the workpiece encompassing, for example, U-shaped and / or a wrench not unlike, support member.

LIST OF REFERENCE NUMBERS

2

workpiece

3

gripper

3A, 3B

gripping element

4

stretching device

4A, 4B

Reck tool

5

Drehmomentabstützeinrichtung

5A, 5B

supporting

20

Griffin area

21, 22, 23

subregion

21 'to 25'

(reshaped) subarea

26

subregion

41.42

forming surface

51, 52

support surface

A

axis

B

axial length

B1, B2, B3

axial length

C

axial length

G

cross axis

R

Reck movement

V

Direction of rotation

α1, α4

angle of rotation

β

cross angle

Ax

axial way

d, e, e '

axial distance

Claims (22)

Process for the stretch-forging of workpieces, in which the following method steps are carried out at least once, preferably in a plurality of successions: a) carrying out a relative movement of a heated metallic workpiece and / or in a flowable state ( 2 ) in a stretching direction (V) relative to at least two stretching tools ( 4A . 4B ) by means of at least one gripping device ( 3 ), b) turning the workpiece ( 2 ) by means of the gripping device (s) ( 3 ) with respect to an axial direction to the stretching direction (V) and / or one, preferably by the workpiece ( 2 ) extending axis (A) by a predetermined angle of rotation (α1), wherein the movements of steps a) and b) in any order can be carried out sequentially or simultaneously, c) supporting the workpiece ( 2 ) in a subarea ( 22 ' . 25 ' ) by at least one support element ( 5A . 5B ) a torque support device ( 5 ) with this subarea ( 21 ' . 24 ' ) of the workpiece ( 2 ) is brought into contact surface or positive fit, d) reshaping a further subarea ( 23 . 26 ) of the workpiece ( 2 ), which belongs to the supported subarea ( 21 ' . 24 ' ) is offset axially relative to the axis (A) and / or counter to the stretching direction (V), in a forming step by feeding at least one of the stretching tools ( 4A . 4B ) to the workpiece ( 2 ), wherein the at least one support element ( 5A . 5B ) in this reshaping of the further subarea ( 23 . 26 ) on the supported portion ( 21 ' . 24 ' ) exerts or absorbs at least partially exerted torque and thereby a torque load on the gripping device ( 3 ) and / or to one between the at least one support element ( 5A . 5B ) and the gripping device ( 3 ) lying portion of the workpiece ( 2 ) reduces or prevents, e) retrieving the delivered stretching tool or tools (s) ( 4A . 4B ) and preferably also the or each support element ( 5A . 5B ) of the workpiece ( 2 ). Method according to Claim 1, in which the supported subregion ( 21 ' . 24 ' ) a partial area already formed in an earlier forming step ( 21 ' . 24 ' ) of the workpiece ( 2 ). Method according to Claim 1 or Claim 2, in which the relative movement between the workpiece ( 2 ) and stretching tools ( 4A . 4B ) is a translation movement axially of the axis (A). Method according to one of Claims 1 to 3, in which any relative movement between the workpiece ( 2 ) and stretching tools ( 4A . 4B ) in the stretching direction (V) about a predetermined axial path (.DELTA.x) axially to the axis (A). Method according to Claim 4, in which the predetermined axial travel (Δx) in the case of several or all relative movements between the workpiece (Δx). 2 ) and stretching tools ( 4A . 4B ) is constant. Method according to one of the preceding claims, in which at least two of the subregions (reshaped or reshaped) ( 21 . 22 . 23 . 26 . 21 ' to 25 ' ) of the workpiece partially overlap axially with respect to the stretching direction (V) and / or axis (A). A method according to claim 4 or claim 5 or claim 6 when dependent on claim 4 or claim 5, wherein the axial path (Δx) is less than an axial dimension (B) of the stretching tools ( 4A . 4B ), in particular between one third and two thirds of the axial dimension (B) of the stretching tools ( 4A . 4B ) is selected. Method according to one of the preceding claims, in which between the supported portion ( 21 ' . 24 ' ) and at least one further already reshaped partial region lies with the further partial region which has been formed or shaped by means of the stretching tools. Method according to one of the preceding claims, wherein the angle of rotation (α, α1, Δα) with each rotation of the workpiece ( 2 ) is selected according to the desired twist of the workpiece and / or the differential rotational angle (Δα) between two rotational angles of successive rotational steps is chosen constant or variable, and in particular from a range between 0.5 ° and 15 °, in particular between 1 ° and 5 °, is selected. Method according to one of the preceding claims, having at least one of the following features: 2 ) is controlled by one or two gripping devices ( 3 ) in each one associated, preferably at one end of the workpiece ( 2 ), gripping area ( 20 ) and, also during the relative movement and / or the rotational movement, held in a position aligned along the axis (A), which is preferably a substantially horizontal position; - the gripping device ( 3 ) grips the workpiece ( 2 ) by means of two opposing gripping elements ( 3A . 3B ), - the feed movement and return movement of the stretching tool or tools (s) ( 4A . 4B ) and / or supporting elements (s) ( 5A . 5B ) takes place vertically and / or perpendicular to the direction of stretching (V) and / or to the axis (A), - the stretching tool or tools ( 4A . 4B ) work either press-bound or tied away or beating or work-bound, - the stretching tools ( 4A . 4B ) have mutually facing convexly curved or spherical forming surfaces ( 41 . 42 ), which are in the workpiece ( 2 ) when impressing or impinging as a complementary concave contour, - the workpiece ( 2 ) has before the first forming step and / or in the gripping area ( 20 ) a polygonal, in particular rectangular, preferably square, or round, in particular circular, cross-section perpendicular to the axis (A), Device for stretch forging of heated and / or in a flowable state metallic workpieces, in particular for performing a method according to any one of the preceding claims, comprising a) a stretching device ( 4 ) with at least two stretching tools ( 4A . 4B ), wherein for forming a workpiece ( 2 ) at least one of the stretching tools ( 4A . 4B ) to the workpiece ( 2 ) can be delivered or delivered, b) at least one gripping device ( 3 ) for gripping the workpiece ( 2 ), Performing a relative movement of the workpiece ( 2 ) in a stretching direction (V) relative to the at least two stretching tools ( 4A . 4B ) and turning the workpiece ( 2 ) with respect to an axial direction to the stretching direction (V) and / or one, preferably by the workpiece ( 2 ) extending axis (A) by a predetermined angle of rotation (α1), c) a torque support device ( 5 ) for supporting the workpiece ( 2 ) in a subarea ( 22 ' . 25 ' ), which at least one support element ( 5A . 5B ) comprises at least one support surface ( 51 . 52 ) associated with this subarea ( 21 ' . 24 ' ) of the workpiece ( 2 ) can be brought or brought into contact with one another in a planar or positive manner, and that when forming a further sub-region ( 23 . 26 ) of the workpiece ( 2 ), which belongs to the supported subarea ( 21 ' . 24 ' ) is displaced axially relative to the axis (A) and / or opposite to the stretching direction (V), one during the forming of the further partial region (A) 23 . 26 ) by the stretching tools ( 4A . 4B ) on the supported portion ( 21 ' . 24 ' ) exerts or absorbs at least partially exerted torque and thereby a torque load on the gripping device ( 3 ) and / or to one between the at least one support element ( 5A . 5B ) and the gripping device ( 3 ) lying portion of the workpiece ( 2 ) reduced or prevented. Apparatus according to claim 11, in which the relative movement between the workpiece ( 2 ) and stretching tools ( 4A . 4B ) is a translation movement axially to the axis (A) and / or in which any relative movement between the workpiece ( 2 ) and stretching tools ( 4A . 4B ) in the stretching direction (V) about a predetermined axial path (.DELTA.x) axially to the axis (A), wherein the predetermined axial travel (.DELTA.x) in the case of several or all relative movements between the workpiece ( 2 ) and stretching tools ( 4A . 4B ) is preferably constant. Apparatus according to claim 11 or 12, wherein the axial path (Δx) is smaller than an axial dimension (B) of the stretching tools ( 4A . 4B ), in particular between one third and two thirds of the axial dimension (B) of the stretching tools ( 4A . 4B ) is selected. Device according to one of claims 11 to 13, wherein the supported portion ( 21 ' . 24 ' ) a partial area already formed in an earlier forming step ( 21 ' . 24 ' ) of the workpiece ( 2 ) and / or between the supported subregion ( 21 ' . 24 ' ) and at least one further already reshaped partial region lies with the further partial region which has been formed or shaped by means of the stretching tools. Device according to one of claims 11 to 14, comprising at least two gripping devices ( 3 ) for gripping the workpiece ( 2 ) in each one associated, preferably at one end of the workpiece ( 2 ), gripping area ( 20 ). Device according to one of claims 11 to 15, in which the gripping device (s) ( 3 ) the workpiece ( 2 ), even during the relative movement and / or the rotational movement, in a aligned along the axis (A) position or hold, which is preferably a substantially horizontal position. Device according to one of claims 11 to 16, wherein the feed movement and return movement of the stretching tool or tools (s) ( 4A . 4B ) is directed vertically and / or perpendicular to the stretching direction (V) and / or to the axis (A). Device according to one of claims 11 to 17, in which the stretching device ( 4 ) is or comprises a work-bound or bound forming machine, preferably a forging hammer or a forging press. Device according to one of claims 11 to 18, in which the stretching tools ( 4A . 4B ) facing each other in the axial direction convexly curved or spherical forming surfaces ( 41 . 42 ) which extend into the workpiece ( 2 ) when impressed or impinged as a complementary concave contour. Device according to Claim 19, in which the support element or elements (e) 5A . 5B ) in the axial direction convexly curved support surface (s) ( 51 . 52 ) or have, which at the convexly curved forming surfaces ( 41 . 42 ) of the stretching elements ( 4A . 4B ) is or are adapted in the form and / or axially large over substantially its entire axial length (C) on the workpiece ( 2 ) can or can support. Device according to one of Claims 11 to 20, in which the axial length (C) of the support element or elements (s) ( 5A . 5B ) or the support surface (s) ( 51 . 52 ) is smaller than the axial length (B) of the stretching elements ( 4A . 4B ) or its forming surface (s) ( 41 . 42 ). Device according to one of Claims 11 to 21, in which the support surface (s) ( 51 . 52 ) in one or each of the axial direction or the axis (A) perpendicular cross-sectional plane over a large area on the workpiece ( 2 ) and / or in this cross-sectional plane substantially by one of the angle of rotation or the differential rotational angle (Δα) of the rotational movement of the workpiece ( 2 ) is tilted corresponding inclination angle.

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