Isothermal forging system

Abstract

The invention relates to a system for isothermally forging metal semifinished products close to the final contours using a vacuum and / or a protective gas atmosphere, comprising at least one forging press (1) which comprises at least one press ram (4) that extends into a vacuum forging chamber (3), at least one upper tool (5), and at least one lower tool (6); at least one workpiece changing chamber (9) which is connected to the vacuum forging chamber (3) in a gas-tight manner; and a plurality of lock chambers (11, 12) for preparing and / or heating and / or cooling workpieces, said lock chambers being connected to the workpiece changing chamber (9) in a gas-tight manner, wherein at least the vacuum forging chamber (3) has at least one round cross-sectional contour.

Description

[0001] Isothermal forging plant

[0002] The invention relates to a plant for the isothermal forging of near-net-shape metal semi-finished products under vacuum and / or protective gas atmosphere with at least one forging press comprising at least one press ram extending into a vacuum forging chamber, at least one upper tool and at least one lower tool.

[0003] Processes and systems for isothermal forging of near-net-shape metal semi-finished products under vacuum are generally known in the art. In these processes, also known as HIF (Hot Isothermal Forging), titanium or molybdenum materials or so-called superalloys are forged into shape at high temperatures with low deformation rates under superplastic conditions. Turbine blades, for example, are manufactured in this way. One such manufacturing process is known, for example, from US Pat. No. 5,933,951 A.

[0004] The HIF process is particularly distinguished by the fact that both the forging tools and the workpieces are heated under vacuum to a temperature that allows superplastic deformation of the workpiece prior to the forging process. It is known to preheat the semi-finished products to be formed in a manipulator tunnel before the forging process and to feed the preheated workpiece into a heated vacuum forging chamber.

[0005] Existing isothermal forging systems are complex, as reliably achieving the vacuum pressure of less than 0.05 mbar required for the forging process and maintaining low leakage rates are challenging. Due to the long preheating times for the workpieces and the long heating times for the tools, the cycle times for the production of individual parts and the system changeover times for any necessary tool changes are long.

[0006] The invention is therefore based on the object of providing a system of the type mentioned above that is characterized by low leakage losses. Furthermore, the invention is particularly based on the object of providing a system of the type mentioned above that enables short cycle and changeover times when carrying out the isothermal forging process.

[0007] The object is achieved by a system having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims.

[0008] According to one aspect of the present invention, a plant is provided for the isothermal forging of near-net-shape metal semi-finished products under vacuum and / or a protective gas atmosphere, comprising at least one forging press, which comprises at least one press ram extending into a vacuum forging chamber, at least one upper tool and at least one lower tool, with at least one workpiece changing chamber which is connected in a gas-tight manner to the vacuum forging chamber and with a plurality of lock chambers for the provision and / or heating and / or cooling of workpieces which are connected in a gas-tight manner to the workpiece changing chamber, wherein at least the vacuum forging chamber has at least one round cross-sectional contour.

[0009] Preferably, the vacuum forging chamber and at least the workpiece changing chamber are designed to be evacuatable and are each connected to a vacuum source.

[0010] Gas-tight, in the context of the present invention, refers in particular to a tightness that allows for evacuation. A round cross-sectional contour is particularly advantageous with regard to the mechanical strength of the structure when subjected to negative pressure. Furthermore, the resulting round transitions, connections, and feedthroughs are easier to seal and result in lower leakage losses.

[0011] In the system according to the invention, it can be provided that the vacuum forging chamber has a circular cross-sectional contour and round passages and round openings.

[0012] In the preferred variant of the system according to the invention, the vacuum forging chamber is designed as a substantially cylindrical chamber with round passages and connections, with the transitions to the upper and lower end faces preferably also being rounded. Any maintenance openings provided in the vacuum forging chamber are also preferably circular or oval openings with corresponding closures.

[0013] In a particularly advantageous variant of the system according to the invention, the workpiece changing chamber and the lock chambers also have round cross-sections.

[0014] The vacuum forging chamber, the workpiece change chamber, and the lock chambers can be connected in a gas-tight manner via round connectors and / or feedthroughs. This creates a tubular, modular system. Furthermore, multiple workpieces can be prepared, heated, and fed into the vacuum forging chamber in parallel.

[0015] Preferably, at least one tool change chamber is provided, which is also designed as a tubular component with a circular cross-section. A tool change chamber, which is connected to the vacuum forging chamber, for example, diametrically opposite the workpiece change chamber, has the advantage that tools for converting the forging press to other components can be kept preheated in the tool change chamber. The heating time for a tool can be up to 24 hours, for example, so that the design of the system with a tool change chamber has the advantage that conversion to other tools can be carried out with little loss of time. The tool change chamber can also be provided with a plurality of lock chambers for the introduction of various upper tools and various lower tools under vacuum.The lock chambers of the tool change chamber are also expediently designed to be gas-tight and lockable relative to the tool change chamber by means of appropriately designed vacuum slides.

[0016] The lock chambers of the workpiece change chamber and / or the tool change chamber can, for example, be closed off from the atmosphere with circular hatches.

[0017] The vacuum slides are conveniently equipped with round slide plates.

[0018] In a particularly advantageous variant of the system according to the invention, a plurality of vacuum pumps are provided, which are arranged below a furnace floor, preferably in a plant basement. Such an arrangement makes it possible to arrange the vacuum pumps directly below the individual chambers of the system, so that the number of required vacuum lines, the length of the vacuum lines, and the number of required vacuum distributors can be minimized, which also contributes to reducing leakage losses. Arranging the vacuum pumps above the furnace floor would require longer line runs, since the lines would have to be laid around the system and the individual chambers could not be connected directly.

[0019] At least one vacuum pump can be arranged directly below the vacuum forging chamber and below the workpiece changing chamber and preferably also below the tool changing chamber.

[0020] Preferably, the workpiece change chamber, the lock chambers, and preferably also the tool change chamber are assembled as tubular components in a modular design, so that the system can be expanded to include as many lock chambers as required. For example, several tubular components can be combined to form a tunnel-shaped workpiece change chamber. Likewise, several tubular components can be combined to form a tunnel-shaped tool change chamber. Tubular lock chambers can be connected to both sides of the tool change chamber and / or the workpiece change chamber.

[0021] At least one horizontally movable manipulator for handling the workpieces is arranged in the workpiece changing chamber. A movable manipulator for handling the tools can also be provided in the tool changing chamber.

[0022] The passage of the press ram into the vacuum forging chamber advantageously includes water cooling.

[0023] In a preferred and advantageous embodiment of the system according to the invention, the pressure stage of the vacuum forging chamber comprises at least two sealing flanges in the area of ​​the press ram passage, which interact with a sealing system of the press ram on the inside. The flanges are preferably connected to one another via at least one stainless steel bellows, preferably via two such bellows.

[0024] The invention is explained below using an embodiment with reference to the accompanying drawings.

[0025] They show:

[0026] Figure 1 is a partial sectional view through a system according to the invention,

[0027] Figure 2 is a plan view of the system according to the invention,

[0028] Figure 3 is a schematic perspective view of the system according to the invention,

[0029] Figure 4 is a schematic sectional view showing the press ram as well as the upper and lower tools of the forging press,

[0030] Figure 5 is a perspective partial sectional view of the vacuum forging chamber and the tool changing chamber connected to it,

[0031] Figure 6 is a schematic representation of a lock chamber designed as a heating chamber and

[0032] Figure 7 is a perspective view of a vacuum slide valve.

[0033] The system for isothermal forging of metal semi-finished products shown in Figure 1 comprises a forging press 1 with four columns 2 and a press ram 4 extending into a vacuum forging chamber 3 with an upper tool 5 (see Figure 4), which interacts with a lower tool 6 arranged in the vacuum forging chamber 3 to form a heated semi-finished product 7. In the system according to the invention, the press ram 4 is hydraulically displaceable vertically or axially, and is sealed in a passage 8 of the vacuum forging chamber 3. The invention is to be understood in such a way that the press ram can also be mechanically displaced.

[0034] The vacuum forging chamber 3 is connected, on the one hand, to a workpiece change chamber 9 and, on the other hand, to a tool change chamber 10. First lock chambers 11 are connected to the workpiece change chamber 9, while second lock chambers 12 are connected to the tool change chamber. The vacuum forging chamber 3, the workpiece change chamber 9, the tool change chamber 10, as well as the first and second lock chambers 11, 12, are each evacuatable and connected to one another in a gas-tight manner. For this purpose, all chambers 3, 9, 10, 11, 12 are connected to vacuum pumps 13, which are located below a furnace corridor 14 beneath the plant in a plant basement 15.

[0035] Semi-finished products 7 can be introduced into the workpiece changing chamber 9 via the first lock chambers 11, and finished forged products can be removed from the workpiece changing chamber 9. This is accomplished by means of a manipulator 16 that can be moved linearly and essentially horizontally within the workpiece changing chamber 9. The workpiece changing chamber 9 is designed as a tubular tunnel for handling the semi-finished products 7 and the finished products. The tunnel has a round, circular cross-section, with which it is connected to a correspondingly designed opening in the vacuum forging chamber 3. The first lock chambers 11 are also designed as tubular components that have a round, circular cross-section, with which they are laterally connected to correspondingly designed openings in the workpiece changing chamber 9.The first lock chambers 11 are sealed gas-tight against the atmosphere by appropriately designed round hatches 18 and can be sealed against the workpiece changing chamber 9 by means of vacuum slide valves 23. At least some of the first lock chambers 11 are provided with heating devices 19 for preheating the semi-finished products 7.

[0036] A first lock chamber 11 designed as a heating chamber is shown in Figure 6. This comprises the heating device designated 19 and a hydraulically lowerable hood 20, which encloses the semi-finished product 7 during the heating process to accelerate the heating process. The heating device 19 is designed as a heating plate with at least one resistance heating element.

[0037] The second lock chambers 12 are designed correspondingly to the first lock chambers 11 and are each laterally connected to the tool change chamber 10. The tool change chamber 10, likewise a tubular component with a circular cross-section, is connected to a correspondingly designed opening in the vacuum forging chamber 3. The vacuum forging chamber 3 can be closed off from both the workpiece change chamber 9 and the tool change chamber 10 by means of a vacuum slide valve 23. Tools, upper tools 5 on the one hand and lower tools 6 on the other, can be introduced into and removed from the tool change chamber 10 through the second lock chambers 12. For this purpose, a horizontally movable lifting carriage 17 is preferably provided in the tool change chamber 10. The tools are moved into the vacuum forging chamber 3 by the lifting carriage 17, where they are coupled to the press ram 4 by a corresponding lifting movement.

[0038] The vacuum forging chamber 3 has, as can be seen particularly from the illustration in Figure 5, a circular cross-section and is designed as an approximately cylindrical housing. The transitions from the cylindrical wall of the vacuum forging chamber 3 to the upper and lower end faces can be rounded. In this respect, the illustration according to Figure 5 is simplified, and this detail is not visible in Figure 5. For reasons of simplification, parts of the front columns 2 of the forging press 1 are also not shown in Figure 5.

[0039] As can be seen from the illustration in Figure 5, the vacuum slides 23 comprise circular slide plates 24, which are shown closed in Figure 5. Via the second lock chambers 12, which can also be closed with hatches 18, an upper tool 5 and a lower tool 6 can be inserted into or removed from the tool change chamber 10 on either side of the tool change chamber 10. In the variant of the system shown in Figure 5, two second lock chambers 12 are connected to the tool change chamber 10. According to the invention, the tool change chamber 10 can be expanded by appropriately designed tubular components, to which further second lock chambers 12 are then connected, so that a large number of tools can be preheated in a ready position.A correspondingly modular structure is provided for the workpiece changing chamber 9 and the first lock chambers 11 connected to it.

[0040] As can be seen from the illustration in Figure 3, the workpiece changing chamber 9 and the tool changing chamber 10 are each provided with front-end openings, which can also be closed with hatches 18. In addition, the vacuum forging chamber 3 is provided with a maintenance opening 21, which is closed with a maintenance door 22. The maintenance opening 21 and the maintenance door 22 are also round, since these contours can be sealed more easily and with less force. In the forging process, it is provided that the semi-finished products 7 are first introduced into one or more of the first lock chambers 11 by means of a manipulator, lifting truck or the like. When the respective lock chamber 11 is opened, it is sealed gas-tight with respect to the workpiece changing chamber 9 by means of a vacuum slide 23.The first lock chamber 11 is then closed and, after appropriate evacuation and preheating of the semi-finished product 7 by means of a heating device 19, is connected to the workpiece changing chamber 9 by actuating the vacuum slide 23. The heated semi-finished product 7 is then taken over by the manipulator 16 and, as shown in Figure 4, inserted into the lower tool 6 of the forging press 1. For the purpose of forming the forged part, the upper tool 5 and the lower tool 6 are closed by actuating the press ram 4. After completion of the forged part, it is again removed by the manipulator 16 and placed in a first lock chamber 11 for cooling and subsequent removal.

[0041] List of reference symbols

[0042] 1 forging press

[0043] 2 pillars

[0044] 3 vacuum forging chamber

[0045] 4 press rams

[0046] 5 Upper tool

[0047] 6 Lower tool

[0048] 7 Semi-finished products

[0049] 8 Implementation

[0050] 9 Workpiece changing chamber

[0051] 10 tool change chamber

[0052] 11 first lock chambers

[0053] 12 second lock chambers

[0054] 13 vacuum pumps

[0055] 14 Hut corridor

[0056] 15 plant cellars

[0057] 16 Manipulator

[0058] 17 pallet trucks

[0059] 18 hatches

[0060] 19 Heating device

[0061] 20 hood

[0062] 21 Maintenance opening

[0063] 22 Maintenance door

[0064] 23 vacuum slide valves

[0065] 24 Slide plate

Claims

Patent claims 1. Plant for isothermal forging of near-net-shape metal semi-finished products under vacuum and / or protective gas atmosphere with at least one forging press (1) comprising at least one press ram (4) extending into a vacuum forging chamber (3), at least one upper tool (5) and at least one lower tool (6), with at least one workpiece exchange chamber (9) which is gas-tightly connected to the vacuum forging chamber (3) and with a plurality of lock chambers (11, 12) for providing and / or heating and / or cooling workpieces which are gas-tightly connected to the workpiece exchange chamber (9), wherein at least the vacuum forging chamber (3) has at least one round cross-sectional contour.

2. System according to claim 1, characterized in that the vacuum forging chamber (3) is designed as a substantially cylindrical chamber with round passages and connections.

3. System according to one of claims 1 or 2, characterized in that the workpiece exchange chamber (9) and the lock chambers (11 , 12) have round cross-sections.

4. Plant according to one of claims 1 to 3, characterized in that the vacuum forging chamber (3), the workpiece exchange chamber (9) and the lock chambers (11 , 12) are connected to each other gas-tight via round feedthroughs.

5. System according to one of claims 1 to 4, characterized by at least one tool change chamber (10) which is connected to the vacuum forging chamber (3).

6. System according to claim 5, characterized in that the tool change chamber (10) has at least a round cross-section and is designed as a tubular component.

7. System according to one of claims 1 to 6, characterized in that further lock chambers (12) are connected to the tool change chamber (10) via vacuum slides (23).

8. System according to claim 7, characterized in that the vacuum slides (23) have round slide plates (24).

9. Plant according to one of claims 1 to 8, characterized in that it comprises a plurality of vacuum pumps (13) which are arranged below a shed floor (14) preferably in a plant basement (15).

10. System according to one of claims 1 to 9, characterized in that at least one vacuum pump (13) is arranged below the vacuum forging chamber (3) and below the workpiece changing chamber (9) and preferably also below the tool changing chamber (10).

11. Plant according to one of claims 1 to 10, characterized in that the workpiece exchange chamber (9), the lock chambers (11 , 12) and preferably also the tool exchange chamber (10) are assembled as tubular components in a modular design. A system according to any one of claims 1 to 11, characterized in that at least some of the lock chambers (11, 12) each have at least one heating device (19) for heating the workpieces or a tool. A system according to any one of claims 1 to 12, characterized in that at least one horizontally movable manipulator (16) for handling the workpieces is arranged at least in the workpiece exchange chamber (9).

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