ISOTHERMAL FORGING PLANT

Description

[0001] The invention relates to a system for isothermal forging of near-net-shape metallic 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.

[0002] Processes and equipment for the isothermal forging of near-net-shape metallic semi-finished products under vacuum are generally known in the prior art. In these processes, also known as HIF (Hot Isothermal Forging), materials such as titanium or molybdenum alloys, 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. Such a manufacturing process is known, for example, from US 5,933,951A.

[0003] The HIF process is characterized in particular by the fact that both the forging tools and the workpieces are heated under vacuum to the temperature that allows superplastic deformation of the workpiece before 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 load a heated vacuum forging chamber with the preheated workpiece.

[0004] Known isothermal forging systems are complex because reliably achieving the vacuum pressure of less than 0.05 mbar required for the forging process and maintaining low leakage rates is costly.

[0005] Due to the fact that a long preheating time for the workpieces and a long heating time for the tools are required, the cycle times for the production of the individual parts as well as the changeover times for the systems in the event of a necessary tool change are large.

[0006] A generic system is known, for example, from US 3,893,318 A. Further prior art is known from publications US 3,698,219 A and JP S59 225840 A.

[0007] The invention is based on the objective of providing a system of the type mentioned above that is characterized by low leakage losses. The invention is further specifically based on the objective of providing a system of the type mentioned above that enables short cycle and changeover times when carrying out the isothermal forging process.

[0008] The problem is solved by a system with the features of claim 1. Advantageous embodiments of the invention are set out in the dependent claims.

[0009] According to one aspect of the present invention, a system for the isothermal forging of near-net-shape metal semi-finished products under vacuum and / or a protective gas atmosphere is provided, comprising at least one forging press. This press includes at least one press ram extending into a vacuum forging chamber, at least one upper die, and at least one lower die. The system also includes at least one workpiece exchange chamber, which is gas-tightly connected to the vacuum forging chamber, and a plurality of airlock chambers for supplying, heating, and / or cooling workpieces, which are also gas-tightly connected to the workpiece exchange chamber. The vacuum forging chamber has at least one round cross-sectional contour. Preferably, the vacuum forging chamber and at least the workpiece exchange chamber are designed to be evacuated and are each connected to a vacuum source.

[0010] In the context of the present invention, "gas-tight" refers in particular to a tightness that allows for evacuation.

[0011] A round cross-sectional contour is particularly advantageous for the mechanical strength of the structure when subjected to negative pressure. Furthermore, resulting round transitions, connections, and penetrations are easier to seal with lower leakage losses.

[0012] 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 as well as round openings.

[0013] In the preferred embodiment of the system according to the invention, the vacuum forging chamber is designed as a substantially cylindrical chamber with round passages and connections, wherein the transitions to the upper and lower end faces are preferably also rounded. Any maintenance openings provided in the vacuum forging chamber are also preferably designed as circular or oval openings with corresponding closures.

[0014] In a particularly advantageous variant of the system according to the invention, the workpiece exchange chamber and the lock chambers also have round cross-sections.

[0015] The vacuum forging chamber, the workpiece exchange chamber, and the airlock chambers can be gas-tightly connected to one another via round connecting elements and / or feedthroughs. In this way, a tubular modular system can be provided. Furthermore, several workpieces can be simultaneously prepared, heated, and fed into the vacuum forging chamber.

[0016] According to the invention, 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 preheated and stored in the tool change chamber. The heating time for a tool can, for example, be up to 24 hours, so the design of the system with a tool change chamber has the advantage that a changeover to other tools can be carried out with minimal time loss. The tool change chamber can also be provided with a plurality of feed chambers for introducing different upper tools and different lower tools under vacuum.The lock chambers of the tool change chamber are also expediently designed to be gas-tight relative to the tool change chamber by means of appropriately designed vacuum slides.

[0017] The lock chambers of the workpiece exchange chamber and / or the tool exchange chamber can, for example, be closed off from the atmosphere with circular hatches.

[0018] The vacuum slide valves are expediently equipped with round slide plates.

[0019] In a particularly advantageous embodiment of the system according to the invention, a plurality of vacuum pumps are provided, arranged below a cabin floor, preferably in a basement. Such an arrangement makes it possible to position the vacuum pumps directly below each individual chamber of the system, thus minimizing the number and length of vacuum lines required, as well as the number of vacuum distribution units, which also contributes to reducing leakage losses. If the vacuum pumps were arranged above the cabin floor, longer pipe runs would be necessary, as the lines would have to be routed around the system and the individual chambers could not be connected directly.

[0020] 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.

[0021] Preferably, the workpiece change chamber, the airlock chambers, and preferably also the tool change chamber are assembled as tubular components in a modular design, so that the system can be expanded by the required number of airlock chambers. Several tubular components can, for example, be joined together to form a tunnel-shaped workpiece change chamber. Likewise, several tubular components can be joined together to form a tunnel-shaped tool change chamber. Tubular airlock chambers can be connected to both sides of the tool change chamber and / or the workpiece change chamber.

[0022] At least one horizontally movable manipulator for handling workpieces is arranged in the workpiece change chamber. Similarly, a movable manipulator for handling tools may be provided in the tool change chamber.

[0023] The insertion of the press ram into the vacuum forging chamber expediently includes water cooling.

[0024] In a preferred and advantageous embodiment of the system according to the invention, the pressure stage of the vacuum forging chamber in the area of ​​the press ram passage comprises at least two sealing flanges which interact internally with a sealing system of the press ram. The flanges are preferably connected to each other via at least one stainless steel bellows, preferably via two such bellows.

[0025] The invention is explained below with reference to an exemplary embodiment and the accompanying drawings.

[0026] They show: Figure 1 is a partial sectional view through a system according to the invention, Figure 2 is a top view of the system according to the invention, Figure 3 is a schematic perspective view of the system according to the invention, Figure 4 is a schematic sectional view showing the press ram as well as the upper and lower tools of the forging press, Figure 5 is a perspective partial sectional view of the vacuum forging chamber and the tool change chamber connected thereto, Figure 6 is a schematic representation of a lock chamber designed as a heating chamber and Figure 7 is a perspective view of a vacuum slide valve.

[0027] The in Figure 1The depicted system for isothermal forging of semi-finished metal products 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 for forming a heated semi-finished product 7. In the system according to the invention, the press ram 4 is hydraulically displaceable vertically or axially, being sealed in a passage 8 of the vacuum forging chamber 3. The invention is to be understood as also allowing the press ram to be mechanically displaceable.

[0028] The vacuum forging chamber 3 is connected on one side to a workpiece exchange chamber 9 and on the other side to a tool exchange chamber 10. First airlock chambers 11 are connected to the workpiece exchange chamber 9, while second airlock chambers 12 are connected to the tool exchange chamber. The vacuum forging chamber 3, the workpiece exchange chamber 9, the tool exchange chamber 10, and the first and second airlock chambers 11 and 12 are each evacuatable and gas-tight, or can be connected to one another. For this purpose, all chambers 3, 9, 10, 11, and 12 are connected to vacuum pumps 13, which are located in a basement 15 below a forge floor 14.

[0029] Semi-finished products 7 can be introduced into the workpiece exchange chamber 9 via the first airlock chambers 11, and finished forged products can be removed from the workpiece exchange chamber 9. This is accomplished by means of a manipulator 16 that moves linearly and essentially horizontally within the workpiece exchange chamber 9. The workpiece exchange chamber 9 is designed as a tubular tunnel for handling the semi-finished products 7 and the finished products, having a round, circular cross-section, which connects it to a correspondingly designed opening in the vacuum forging chamber 3. The first airlock chambers 11 are also designed as tubular components with a round, circular cross-section, which connect them laterally to correspondingly designed openings in the workpiece exchange chamber 9.

[0030] The first airlock chambers 11 are gas-tight to the outside against the atmosphere by means of appropriately designed round hatches 18 and can be closed off from the workpiece exchange chamber 9 via vacuum slide valves 23. At least some of the first airlock chambers 11 are equipped with heating devices 19 for preheating the semi-finished products 7.

[0031] A first lock chamber 11, designed as a heating chamber, is located in Figure 6 This is shown. It comprises the heating device designated 19 and a hydraulically lowerable hood 20, which encloses the semi-finished product 7 during the heating process in order to accelerate the heating process. The heating device 19 is designed as a heating plate with at least one resistance heating element.

[0032] The second lock chambers 12 are designed in accordance with the first lock chambers 11 and are each laterally connected to the tool change chamber 10. The tool change chamber 10 is also a tubular component with a circular cross-section, connected to a correspondingly designed opening in the vacuum forging chamber 3. The vacuum forging chamber 3 can be sealed 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 inserted into and removed from the tool change chamber 10 via the second lock chambers 12. For this purpose, a horizontally movable lifting carriage 17 is preferably provided in the tool change chamber 10. The lifting carriage 17 moves the tools into the vacuum forging chamber 3, where they are coupled to the press ram 4 by a corresponding lifting movement.

[0033] The vacuum forging chamber 3 has, as can be seen in particular from the illustration in Figure 5 As can be seen, it has a circular cross-section and is designed as an approximately cylindrical housing. The transitions of the cylindrical wall of the vacuum forging chamber 3 to the upper and lower end faces may be rounded. In this respect, the illustration is as follows. Figure 5 simplified and this detail is from Figure 5 not apparent. For the sake of simplicity, parts of the front columns 2 of the forging press 1 are shown in Figure 5 also not shown.

[0034] As can be seen from the representation according to Figure 5 As can be seen, the vacuum slides comprise 23 circular slide plates 24, which are located in the Figure 5are shown closed. 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 each side. In the Figure 5 In the illustrated variant of the system, two second lock chambers 12 are connected to the tool change chamber 10. According to the invention, the tool change chamber 10 can be extended 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 corresponding modular design is provided for the workpiece change chamber 9 and the first lock chambers 11 connected to it.

[0035] As this is shown in the representation in Figure 3As can be seen, the workpiece change chamber 9 and the tool change chamber 10 are each provided with end-face openings, which can also be closed with hatches 18. Furthermore, the vacuum forging chamber 3 is provided with a maintenance opening 21, which is closed by a maintenance door 22. The maintenance opening 21 and the maintenance door 22 are also round, as these contours are easier to seal and require less force.

[0036] In the forging process, the semi-finished products 7 are first introduced into one or more of the first lock chambers 11 by means of a manipulator, lifting trolley, or the like. When the relevant lock chamber 11 is opened, it is sealed gas-tight with respect to the workpiece exchange 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, connected to the workpiece exchange chamber 9 by actuating the vacuum slide 23. The heated semi-finished product 7 is then taken over by the manipulator 16 and, as described in Figure 4The workpiece is inserted into the lower die 6 of the forging press 1. To shape the forging, the upper die 5 and the lower die 6 are closed by actuating the press ram 4. After completion of the forging, it is removed again by the manipulator 16 and placed in a first cooling chamber 11 for later removal. Reference symbol list

[0037] 1 Forging press 2 Columns 3 Vacuum forging chamber 4 Press ram 5 Upper tool 6 Lower tool 7 Semi-finished product 8 Feedthrough 9 Workpiece changing chamber 10 Tool changing chamber 11 First lock chambers 12 Second lock chambers 13 Vacuum pumps 14 Forge floor 15 Plant basement 16 Manipulator 17 Lifting trolley 18 Hatches 19 Heating system 20 Hood 21 Maintenance opening 22 Maintenance door 23 Vacuum slide valve 24 Slide plate

Claims

1. Plant for isothermal forging of metallic semi-finished products, which are close to final shape, under vacuum and / or protective-gas atmosphere, with at least one forging press (1), which comprises at least one press ram (4) extending in a vacuum forging chamber (3), at least one upper tool (5) and at least one lower tool (6), with at least one workpiece change chamber (9), which is gas-tightly connected with the vacuum forging chamber (3), and with a plurality of lock chambers (11, 12), which are gas-tightly connected with the workpiece change chamber (9), for preparation and / or heating and / or cooling of workpieces, wherein at least the vacuum forging chamber (3) has at least one round cross-sectional profile, characterised by at least one tool change chamber (10) connected with the vacuum forging chamber (3).

2. Plant according to claim 1, characterised in that the vacuum forging chamber (3) is configured as a substantially cylindrical chamber with round through-passages and connections.

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

4. Plant according to any one of claims 1 to 3, characterised in that the vacuum forging chamber (2), the workpiece change chamber (9) and the lock chambers (11, 12) are gas-tightly connected together by way of round through-passages.

5. Plant according to claim 1, characterised in that the tool change chamber (10) has at least one round cross-section and is configured as a tubular component.

6. Plant according to any one of claims 1 to 5, characterised in that further lock chambers (12) are connected with the tool change chamber (10) by way of vacuum slide valves (23).

7. Plant according to claim 6, characterised in that the vacuum slide valves (23) have round slide valve plates (24).

8. Plant according to any one of claims 1 to 7, characterised in that this comprises a plurality of vacuum pumps (13) arranged below a metallurgical plant floor (14), preferably in a plant basement (15).

9. Plant according to any one of claims 1 to 8, characterised in that at least one respective vacuum pump (13) is arranged below the vacuum forging chamber (3) and below the workpiece change chamber (9) as well as preferably also below the tool change chamber (10).

10. Plant according to any one of claims 1 to 9, characterised in that the workpiece change chamber (9), the lock chambers (11, 12) and preferably also the tool change chamber (10) are combined as tubular components in modular mode of construction.

11. Plant according to any one of claims 1 to 10, characterised 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.

12. Plant according to any one of claims 1 to 11, characterised in that at least one horizontally movable manipulator (16) for manipulating the workpieces is arranged at least in the workpiece change chamber (9).