Smx forging strategy

Abstract

The invention relates to a method for radial forging of a workpiece from an initial state to an end state, preferably following a pass schedule multiple times from an initial state to an end state, by means of a radial forging machine, comprising forging tools arranged around the periphery of the workpiece, preferably four forging tools, wherein the radial forging machine is designed and configured to perform the radial forging in at least three modes of operation, which comprise: A) radial forging in the spiral mode, B) radial forging in the straight mode and C) radial forging in the flat mode, and characterised in that the shaping of the workpiece from an initial state to an end state is a sequence of radial forging passes, wherein at least two of the three different modes of operation are applied in succession. The invention further relates to a radial forging machine for carrying out this method.

Description

[0001] Forging strategy SMX

[0002] The invention relates to a method for radial forging of a workpiece from an initial state to a final state by means of a radial forging machine, comprising forging tools arranged around the circumference of the workpiece, preferably four forging tools, and a radial forging machine for carrying out such a method.

[0003] Radial forging machines are well known to those skilled in the art and feature several, usually four, tools that typically act on the workpiece simultaneously. This virtually completely prevents workpiece expansion; thus, the radial forging process typically only results in workpiece elongation during the forming process from an initial state to a final state with the corresponding geometries.

[0004] Once the workpiece has been formed across its entire length, it is referred to as a single pass. During a pass, the workpiece is formed by repeated tool action; this action can also be referred to as a stroke or tool stroke. The entire forming process of the workpiece is usually carried out through sequential pass sequences in the form of a pass schedule. A pass schedule thus consists of several passes and describes the development of the workpiece geometry from the initial state to the desired final state.

[0005] The forming process on a radial forging machine can essentially be divided into two types of forming: forming, in which the workpiece structure is developed to achieve the required workpiece quality while maintaining the highest possible productivity; and finishing, in which the surface is optimized accordingly. When finishing round cross-sections, a small angle of rotation with a small workpiece feed is typically used to achieve the smoothest and most attractive surface possible.

[0006] In the radial forging machines in question, a number of forging strategies or operating modes are known, as follows:

[0007] A) The most widespread strategy involves carrying out workpiece forming in a spiral forging mode. After each tool stroke, the workpiece is rotated by a defined angle and moved in such a way that in the following stroke, an area that has not yet been fully formed is formed with the help of the tools. This means that the tool completely covers the surface of the workpiece throughout the entire pass. In this spiral forging mode, the movement, i.e. the possible feed, is limited by the maximum tool length and the angle of rotation for the workpiece. With this spiral forging strategy, all forging tools, preferably four, are always in motion during each stroke and thus take part in the forming process, forming the workpiece into the same shape.

[0008] B) Another well-known forging strategy also involves all, preferably four, forging tools forming the workpiece with each stroke, but with no workpiece rotation between strokes. This strategy is called straight-through mode and bears some similarities to common forging processes on open-die forging presses. By omitting the workpiece rotation after a stroke, it is possible to increase the feed rate compared to the spiral forging strategy. For example, when forging an octagonal cross-section, the workpiece surface is not completely overforged in this pass.

[0009] C) A forging strategy for radial forging machines that has rarely been used so far is one in which the tools are controlled in pairs. In this case, opposing tools are controlled together and participate in the forming process, while other tools are controlled at a different time or with a different target dimension. This forging strategy is also referred to as flat mode. In flat mode, it is also possible for a tool pair to remain at a target dimension during the pass, at least limiting the free lateral material flow caused by the tool pair fully participating in the forming process.

[0010] Typically, one of the three forging strategies mentioned above is used to form a workpiece. After the desired forming process has been completed, a finishing process is usually performed to ensure an attractive surface. This involves forming the workpiece around its perimeter to create a workpiece with the desired final geometry, surface finish, and appearance.

[0011] Based on the prior art described above, it was an object of the invention to provide a method for radial forging of a workpiece and a radial forging machine designed and configured to carry out this method, which result in an optimized pass schedule and an optimized workpiece quality.

[0012] This object is achieved according to the invention with a method comprising the features of claim 1 and a radial forging machine comprising the features of claim 10. Advantageous embodiments of the invention are set forth in particular in the dependent claims.

[0013] According to the invention, a method is provided for radial forging of a workpiece from an initial state to a final state, wherein the radial forging is preferably carried out several times following a pass schedule from an initial state to a final state by means of a radial forging machine which comprises forging tools arranged around the circumference of the workpiece. Preferably, four forging tools are arranged around the circumference of the workpiece. The radial forging machine is designed and configured such that it can carry out the radial forging in at least three operating modes, namely A) in spiral mode, B) in straight mode and C) in flat mode. According to the invention, the forming of the workpiece from an initial state to a final state takes place in a sequence of radial forging passes, wherein at least two of the three different operating modes are applied consecutively, i.e. directly and without an intermediate pass.

[0014] The invention refers to a pass as a sequence of forming processes in a predetermined operating mode over the entire length of the workpiece or at least a predetermined partial length of the workpiece. According to the invention, the method for radial forging should comprise at least two different and successive operating modes, for example a first pass in spiral mode, followed by a second pass in straight mode, followed in turn by a third pass in spiral mode, optionally followed by a flat mode. Any conceivable combination of operating modes in the pass sequence is encompassed by the concept of the invention, as long as two consecutive passes implement different operating modes. This means that pass sequences in which several consecutive passes implement the same operating mode, but then followed by a different operating mode, are also encompassed by the concept of the invention.Optionally and preferably, at the end of the forming process within the method according to the invention, surface optimization is achieved by a finishing pass. According to the invention, the finishing pass is not considered as a forming operation and therefore does not represent a separate operating mode. The method according to the invention can improve local deformation and thus improve product quality. Likewise, the process chain can be shortened by reducing pre-forging processes. The method according to the invention allows a forming process that is optimally adapted to the workpiece and its material quality, in particular with the best possible forging of the workpiece as a whole and taking into account the deformation distribution within the workpiece.

[0015] It is preferred if the application and / or sequence of the different operating modes depends on the workpiece material. The requirements that must be considered specifically for certain materials can advantageously be taken into account when preparing the pass schedule. It is particularly preferred if different materials can be grouped into material classes that can, if necessary, be subjected to the same sequence of operating modes. These material classes include, for example, carbon steels, heat-treatable steels, high-speed steels, cold-work steels, hot-work steels, rust- and acid-resistant steels, nickel-based alloys, high-temperature steels, and titanium alloys, to name just a few.For each material class, there may be special requirements regarding the radial forging process, which can then influence the selection of the operating modes and the sequence of the operating modes to be used, depending on the material.

[0016] In this context, it is preferred if, in the spiral mode, the workpiece is rotated at a predetermined angle around its longitudinal axis after each forging tool stroke. It is preferred if all forging tools participate in the forming process, preferably evenly. In an equally preferred embodiment of the invention, in the straight-ahead mode, no rotation of the workpiece around its longitudinal axis occurs after each tool stroke. It is particularly preferred in this context if all forging tools participate in the forming process, preferably evenly.

[0017] In a further preferred embodiment of the invention, in the flat mode of operation, only one forming operation takes place by forging tools arranged opposite one another, preferably by two forging tools arranged opposite one another from a total of four forging tools arranged around the circumference of the workpiece. In the flat mode, the tools that do not participate, or only participate to a limited extent, in a first forming operation can be controlled differently in terms of time or in terms of the forming amount than the forging tools described above that do participate in the forming. Likewise, the forging tools that do not participate in the forming operation can only be positioned close to the workpiece in order to at least limit, and preferably completely prevent, lateral spreading of the workpiece during the radial forging process.Finally, the forging tools that do not participate in the forming process can, of course, remain in an initial position and not make contact with the workpiece, at least for a limited period of time.

[0018] The method according to the invention is preferably carried out using a control device designed and configured to calculate an optimal pass sequence for the workpiece and then specify it to the radial forging machine such that the optimal pass sequence is carried out. In this context, it is particularly preferred if the control of the radial forging machine is carried out on the basis of a pass schedule calculation program that generates an optimal pass sequence taking into account the optimal forging strategies. Preferably, in addition to the starting and ending geometry of the workpiece, the starting temperature, for example the furnace temperature, and particularly preferably also the material grade are specified. The technology program can then calculate the best pass sequence using all possible forging strategies.It is particularly preferred if the intermediate dimensions after each tool stroke, as well as the forging strategy, are calculated in such a way that the best strain distribution is achieved at the end of the pass sequence. This can be achieved, for example, by comparing the strain distribution at the end of the process and calculating all possible combinations of pass sequences and passes in different operating modes. The forging strategy is preferably designed taking into account the system force and the available tool geometries.

[0019] A particularly suitable technology program for pass schedule calculation for such purposes is the Comforge® technology package, which, with data from all industrially relevant materials, has all the prerequisites for calculating the corresponding forging schedules. Comforge® provides plant operators with a comprehensive database of trouble-free and technologically proven forging processes. It is particularly advantageous if an automation system monitors and controls all plant components, control devices, and sensors. With appropriate application of the Comforge® technology package, the forging process from start to finish - the geometry of the forming process, the forces acting during it and the temperatures to be observed, as well as the time for each pass - can be pre-calculated and modeled for the entire forging process.

[0020] According to a second aspect of the present invention, a radial forging machine is provided for carrying out the method according to the first aspect of the invention. According to the invention, the radial forging machine is provided with a control device designed and configured to control the radial forging machine based on a pass schedule calculation program. This pass schedule calculation program preferably takes into account the starting and desired final geometry, the starting temperature of the radial forging process, and the material quality of the workpiece itself. In this context, it is particularly preferred if the pass schedule calculation program also takes into account intermediate dimensions of the workpiece with the aim of achieving an optimal strain distribution on the workpiece.According to the invention, the plant operator is provided with a method and a radial forging machine intended for this purpose, which are capable of enabling optimal forming of the workpiece adapted to the material quality and using a sequence of comparatively easily controllable processes.

Claims

Patent claims:

1. A method for radial forging a workpiece from an initial state to a final state, preferably multiple times following a pass schedule from an initial state to a final state, by means of a radial forging machine comprising forging tools arranged around the circumference of the workpiece, preferably four forging tools, wherein the radial forging machine is designed and configured to carry out the radial forging in at least three operating modes, which include A) radial forging in spiral mode, B) radial forging in straight mode and C) radial forging in flat mode, characterized in that the forming of the workpiece from an initial state to a final state takes place as a sequence of radial forging passes, wherein at least two of the three different operating modes are applied consecutively.

2. Method according to claim 1, characterized in that the forming of the workpiece comprises a repeating sequence of different operating modes, preferably beginning with operating mode A), followed by operating mode B), then again operating mode A), or beginning with operating mode B), followed by operating mode A), then again operating mode B), particularly preferably finally followed by operating mode C).

3. Method according to one of the preceding claims, characterized in that all three different operating modes are used in the forming of the workpiece from an initial state to a final state.

4. Method according to one of the preceding claims, characterized in that the application and / or the sequence of the operating modes depends on the material of the workpiece.

5. Method according to one of the preceding claims, characterized in that the final pass is a finishing pass to adjust the surface optimization.

6. Method according to one of the preceding claims, characterized in that in operating mode A) of the spiral mode, the workpiece is rotated at a predetermined angle of rotation about its longitudinal axis after each forging tool stroke, wherein preferably all forging tools participate in the forming.

7. Method according to one of the preceding claims, characterized in that in operating mode B) of the straight-ahead mode, no rotation of the workpiece takes place after each tool stroke, wherein preferably all forging tools participate in the forming.

8. Method according to one of the preceding claims, characterized in that in the operating mode C) of the flat mode, only opposing forging tools, preferably two opposing forging tools of four forging tools arranged around the circumference of the workpiece, participate in the forming.

9. Method according to claim 8, characterized in that the forging tools not participating in the forming are positioned against the circumference of the workpiece in order to at least limit a lateral widening of the workpiece. Radial forging machine for carrying out the method according to one of the preceding claims, characterized in that the radial forging machine is connected to a control device that is designed and configured to calculate an optimal pass sequence for the workpiece and to specify it to the radial forging machine. Radial forging machine according to claim 10, characterized in that the control device is designed and configured to control the radial forging machine based on a pass schedule calculation program that takes into account the starting and desired end geometry as well as the starting temperature of the radial forging process and the material quality of the workpiece. Radial forging machine according to claim 10 or 11, characterized in that the pass schedule calculation program takes into account not only the starting and end geometry but also intermediate dimensions of the workpiece with the aim of achieving an optimal strain distribution in the workpiece.Radial forging machine according to one of claims 10 to 12, characterized in that the control of the radial forging machine takes into account the maximum machine force and the geometries of the available forging tools. Radial forging machine according to one of claims 10 to 13, characterized in that in the operating mode (C) of the flat mode, in which only opposing forging tools, preferably two opposing forging tools of four forging tools arranged around the circumference of the workpiece, can be controlled such that they participate in the forming, wherein the forging tools do not participate in the forming. participating forging tools can be adjusted to the circumference of the workpiece in such a way that lateral widening of the workpiece is at least limited.