Method for rolling an annular workpiece having an open cylindrical cross-section in a ring rolling mill and ring rolling mill for carrying out the method

Abstract

The invention relates to a method for rolling a ring-shaped workpiece (5) having an open cylindrical cross-section in a ring rolling machine (1) during a rolling process with inductive heating of the workpiece (5) using at least one inductor (12), which is held at a predefined coupling distance relative to the workpiece (5) and is moved following or driven by the workpiece (5) during the forming process in accordance with the dimensional changes of the workpiece (5), wherein, by means of the inductor (12), an alternating magnetic field, preferably having a frequency of between 4 kHz and 10 kHz, is coupled directly into the workpiece (5). The invention also relates to a ring rolling machine (1) for carrying out the method.

Description

Technical Field

[0001] The present invention relates to a method for rolling annular pieces having an open cylindrical cross-section in a ring rolling mill when the piece is induction heated during the rolling process.

[0002] The present invention relates in particular to a method for manufacturing metal rings having rectangular or shaped cross sections by rolling, the metal rings being made of different steel grades and special alloys, such as titanium-based alloys, nickel-based alloys, copper alloys and aluminum alloys. Background Technology

[0003] For example, induction heating of the workpiece during the rolling process is basically known from patent document US 2012 / 0279268 A1. This publication relates to a method for forging a ring-shaped workpiece while simultaneously electrically heating the workpiece by induction. The method involves partially or completely surrounding the workpiece with a magnetizable core configured as a closed or C-shape, the core being wound with a coil, and applying a low-frequency alternating current in the range of about 1000 Hz or lower to the coil. This method is both cumbersome and complex, especially because it requires surrounding the workpiece with a magnetic or magnetizable core.

[0004] Other prior art is known from patent documents CN 109590417 A, CN 109663821 A and JP 01237036 A.

[0005] A method for rolling annular pieces having an open cylindrical cross-section in a ring rolling mill and a ring rolling mill for carrying out the method are known from EP 3 385 005 A1. Summary of the Invention

[0006] The object of the present invention is to provide a method of the type mentioned at the beginning, wherein compensation for temperature loss in the workpiece during forming can be easily achieved, especially induction heating of the rolled piece during the rolling process with minimal cost.

[0007] Temperature control during rolling aims to address heat loss, particularly heat loss through radiation. As the size of the workpiece or the diameter of the ring increases during rolling, the surface area increases, leading to increased heat loss. According to the invention, these temperature losses should be compensated for.

[0008] This objective is achieved by the method according to the invention and the ring rolling machine according to the invention.

[0009] According to one aspect of the invention, the method includes using at least one sensor that maintains a pre-given and constant coupling distance relative to the rolled piece and moves in a following or driven manner according to changes in the dimensions of the rolled piece during the forming process, wherein an alternating magnetic field, preferably having a frequency between 4 kHz and 10 kHz, is directly coupled into the rolled piece by means of the sensor.

[0010] In the method according to the invention, instead of surrounding or partially surrounding the workpiece with a conductive core, at least one sensor is positioned at a relatively small distance from the workpiece and held there during the rolling process. In this application, this distance is referred to as the coupling distance, and its dimensions are determined such that an alternating magnetic field can be induced in the workpiece, and consequently, the workpiece can be heated.

[0011] The sensor can be constructed as a flat coil, a C-shaped coil, or an L-shaped coil.

[0012] During the rolling process, the sensor is positioned and held at the outer periphery of the rolled piece. The rolled piece, in the form of a double-sided open cylindrical ring, undergoes dimensional changes during the forming process, wherein the ring preferably has a shaped cross-section. The diameter of the annular rolled piece increases, the height of the ring decreases, and the width of the ring also decreases. Therefore, according to the invention, the sensor is moved to follow the dimensional changes of the rolled piece at a constant coupling distance.

[0013] In principle, the sensor can be fixed to a support arm, which, for example, can move together with the mill stand of the axial rolls used in the ring rolling mill as the diameter of the ring-shaped workpiece increases. The support arm can be fixed to the mill stand, for example.

[0014] Alternatively, it can be specified that the sensor is controlled to follow the movement along the motion axis by means of at least one manipulator in at least one linear and / or rotational motion. This can be achieved, in particular, by means of a multi-axis industrial robot, at which at least one sensor may be arranged.

[0015] The method according to the invention specifies that the actual distance between the sensor and the workpiece is sensed during the rolling process, and the coupling distance is automatically adjusted to a target distance based on the actual distance. This adjustment can be performed by a control unit specifically configured for this purpose on the ring rolling mill. Alternatively, the adjustment can be performed by a separate control unit.

[0016] According to the invention, the actual distance between the sensor and the workpiece is detected in a contact manner by means of at least two contact rollers or a distance holder, wherein the distance between the sensor and the workpiece is predetermined by a distance holder that is attached to the workpiece during the rolling process.

[0017] Additionally, non-contact detection of actual distance can be performed using at least one optical sensor.

[0018] In a preferred variation of the method according to the invention, inductive coupling is specified by at least one inductor in the direction of rotation of the workpiece, at least before the main roll of the ring rolling mill or before the axial roll assembly, such that the workpiece is heated accordingly just before the main roll or axial roll assembly engages with it. The invention should be understood to mean that one or more inductors may be located at any point on the periphery of the workpiece within the ring rolling mill.

[0019] In addition, it may be specified that at least two sensors are positioned around the periphery of the rolled piece. For example, if the rolling mill is constructed as a radial-axial rolling mill, the sensors are positioned at least in front of the main roll and axial roll assembly of the rolling mill along the direction of rotation of the rolled piece.

[0020] As mentioned above, it is suitable to guide the sensor at a support arm that preferably has at least two degrees of freedom, preferably three degrees of freedom. Preferably, the sensor is guided not only linearly but also rotatably.

[0021] According to the present invention, during the rolling process, the sensor is moved as the radius of the cylindrical workpiece increases and the axis of rotation shifts.

[0022] Another aspect of the invention relates to a ring rolling mill, preferably configured to perform the method described above. The ring rolling mill is preferably configured as a radial ring rolling mill or a radial-axial ring rolling mill, and includes at least one driven main roll and at least one cored roll, preferably also including at least two axial rolls, and devices for centering the ring-shaped workpiece, the axial rolls being preferably tapered rolls. The ring rolling mill according to the invention is characterized by at least one sensor that can be positioned at the outer periphery of the workpiece at a predetermined coupling distance relative to the workpiece during the rolling process, and can follow the movement according to changes in the dimensions of the workpiece to maintain a constant coupling distance, wherein an alternating magnetic field preferably having a frequency between 4 kHz and 10 kHz can be induced in the workpiece by the sensor. At least one of the axial rolls can be configured as a driven roll.

[0023] The ring rolling mill can be configured as a radial ring rolling mill or a radial-axial ring rolling mill. Only in the latter case does the ring rolling mill according to the invention include axial rolls.

[0024] A swing arm with a centering roller can be provided as a device for centering the rolled workpiece, the centering roller being attached to the outer periphery of the rolled workpiece during the rolling process.

[0025] In a preferred variant of the ring rolling machine according to the invention, the sensor is fixed to the support arm of the manipulator, which can move with at least two degrees of freedom, preferably three degrees of freedom.

[0026] In another advantageous variant of the rolling mill according to the invention, the inductor is arranged at least before the main roll or the axial roll along the rotation direction of the workpiece.

[0027] Alternatively, it may be specified that sensors are arranged in front of the main rolls and the axial rolls along the direction of rotation of the workpiece.

[0028] This invention should be understood to mean that more than two sensors may also be provided around the periphery of the rolled piece. Attached Figure Description

[0029] The invention will now be described with reference to embodiments shown in the accompanying drawings. Wherein:

[0030] Figure 1 A perspective view of the ring rolling machine according to the present invention is shown;

[0031] Figure 2 A top view of the ring rolling machine according to the present invention is shown; and

[0032] Figure 3 A three-dimensional view of the sensor is shown. Detailed Implementation

[0033] The ring rolling mill 1 shown in the accompanying drawings includes a driven main roll 2 and a rolling table 4. The workpiece, designated 5, is constructed as a closed ring, more precisely as a cylindrical body open on both sides. The workpiece 5 has a rectangular cross-sectional profile and rests on the rolling table 4. The workpiece 5 is radially rolled clockwise between the main roll 2 and a cored roll 3, decreasing in wall thickness, and axially rolled, simultaneously decreasing in height. Here, the workpiece 5 is centered in the ring rolling mill 1 by means of a centering roll 7 fixed to a swing arm 6. The workpiece 5 is rolled axially by means of two axial rolls 8. The axial rolls 8 are tapered rolls and supported in an axial frame 10. The axial frame 10 can be moved or adjusted relative to the midpoint of the workpiece 5, which shifts during rolling due to the increase in radius; that is, it can be moved or adjusted radially relative to the workpiece 5.

[0034] In the described embodiment, a support arm 11 is fixed at the axial frame 10, and a sensor 12 is arranged at its distal end, which points radially inward relative to the workpiece 5. As previously mentioned, the sensor 12 may alternatively be fixed at the articulated arm of an industrial robot, which is positioned around the periphery of the ring rolling mill 1.

[0035] As from Figure 3As can be seen, the inductor 12 includes a transformer unit 14 and an induction coil 15 disposed on the substrate 13. The transformer unit 14 is connected to a capacitor bank (not shown) via air-cooled and / or water-cooled cables, and causes electrical matching between the induced voltage and the output voltage of the frequency converter. The frequency converter operates in a frequency range between 4 kHz and 10 kHz. Two distance holders 16 are also disposed on the substrate 13, with the induction coil 15 located between them. The distance holders 16 are configured as contact rolls extending parallel to the axis of rotation of the workpiece 5, with their roll heads 17 held in engagement with the workpiece 5 during the rolling process. The distance holders 16 are water-cooled. A coolant inlet 18 is provided for the aforementioned distance holders through which coolant flows.

[0036] The induction coil, transformer unit, and distance holder 16 are arranged on the substrate in a manner that is both linearly and rotatably adjustable. Because, as described above, the radius of the workpiece 5 increases during the rolling process, and therefore the distance between the induction coil 15 and the workpiece 5 increases, another linear adjustment is provided between the distance holder 16 and the induction coil 15. This adjustability ensures that the distance between the induction coil 15 and the workpiece remains constant.

[0037] In order to guide and hold the sensor 12 with a constant narrow coupling distance relative to the outer periphery of the workpiece 5 throughout the rolling process, the support arm 11 can also be moved radially relative to the workpiece along with the axial frame 10. During the rolling process, the height of the workpiece 5 will decrease on the one hand, and the diameter of the workpiece 5 will increase on the other hand, so the support arm 11 must be adjusted at least radially relative to the workpiece 5.

[0038] Figure 3 The induction coil 15 shown has a generally L-shaped cross-sectional profile, extending below a portion of the lower side of the annular rolled piece 5. According to the invention, the induction coil may also have other geometries. The induction coil 15 does not necessarily have to extend below the lower side of the annular rolled piece 5.

[0039] List of reference numerals

[0040] 1. Ring rolling machine

[0041] 2 Main Rolls

[0042] 3. Rolls with cores

[0043] 4 Rolling table

[0044] 5 Rolled parts

[0045] 6. Swing arm

[0046] 7 centering rollers

[0047] 8 Axial Rolls

[0048] 9. Controls

[0049] 10-axis frame

[0050] 11 Brackets

[0051] 12 Sensors

[0052] 13 substrate

[0053] 14 Transformer Unit

[0054] 15. Induction coil

[0055] 16 Distance Holder

[0056] 17 Roller Head

[0057] 18. Coolant connector.

Claims

1. A method for rolling an annular piece (5) having an open cylindrical cross-section by inductively heating a piece (5) during the rolling process in a ring rolling mill (1) using at least one inductor (12), the inductor maintaining a predetermined coupling distance relative to the piece (5) and moving in a following or driven manner according to changes in the dimensions of the piece (5) during the forming process, wherein, The alternating magnetic field is directly coupled into the workpiece (5) by means of the sensor (12), characterized in that the actual distance between the sensor (12) and the workpiece (5) is sensedly detected during the rolling process, and the coupling distance is automatically adjusted to a target distance according to the actual distance, the actual distance between the sensor (12) and the workpiece is sensedly detected by means of at least two contact rolls or by means of at least two distance holders (16), the distance holders being engaged with the outer periphery of the workpiece.

2. The method according to claim 1, characterized in that, The sensor (12) is positioned and held at the outer periphery of the rolled piece (5) during the rolling process.

3. The method according to claim 1, characterized in that, The sensor (12) moves in a controlled manner along at least one axis of motion with at least one linear motion and / or rotational motion.

4. The method according to claim 2, characterized in that, The sensor (12) moves in a controlled manner along at least one axis of motion with at least one linear motion and / or rotational motion.

5. The method according to any one of claims 1 to 4, characterized in that, Inductive coupling is performed via at least one sensor (12) at least before the main roll (2) or axial roll assembly of the rolling mill (1) in the rotational direction of the rolled piece (5).

6. The method according to any one of claims 1 to 4, characterized in that, Inductive coupling is performed via at least two sensors (12) at least before the main roll (2) and axial roll assembly of the rolling mill (1) in the rotational direction of the workpiece (5).

7. The method according to any one of claims 1 to 4, characterized in that, The sensor (12) is guided at a support arm (11) having at least two degrees of freedom.

8. The method according to claim 7, characterized in that, The support arm (11) has three degrees of freedom.

9. The method according to any one of claims 1 to 4, characterized in that, The alternating magnetic field has a frequency between 4 kHz and 10 kHz.

10. A ring rolling mill (1) for performing the method according to any one of claims 1 to 6, the ring rolling mill having at least one driven main roll (2), at least one cored roll (3), at least two axial rolls (8) and a device for centering a ring-shaped workpiece (5), and having at least one sensor (12) capable of being positioned at the outer periphery of the workpiece (5) at a predetermined coupling distance relative to the workpiece (5) during the rolling process, and capable of following the movement according to changes in the size of the workpiece (5), wherein, The sensor (12) is capable of inducing an alternating magnetic field in the rolled piece (5), characterized in that the sensor (12) has at least two distance holders (16) that can engage with the outer periphery of the rolled piece (5), and a predetermined distance of at least one induction coil (15) relative to the outer periphery of the rolled piece (5) is given in advance, and the position of the induction coil (15) relative to the distance holders (16) can be adjusted.

11. The ring rolling machine according to claim 10, characterized in that, The sensor (12) is fixed to the support arm (11) of the manipulator (9), which is capable of moving in at least two degrees of freedom.

12. The ring rolling machine according to claim 11, characterized in that, The sensor (12) is fixed to the support arm (11) of the manipulator (9), which is capable of moving in three degrees of freedom.

13. The ring rolling machine according to claim 10, characterized in that, The sensor (12) is fixed at the support arm (11) of the axial frame (10) of the ring rolling machine (1).

14. The ring rolling machine according to any one of claims 10 to 13, characterized in that, The sensor (12) is arranged at least in front of the main roll (2) or the axial roll (8) along the rotation direction of the workpiece (5).

15. The ring rolling machine according to any one of claims 10 to 13, characterized in that, Sensors (12) are arranged in front of the main roll (2) and the axial roll (8) respectively along the rotation direction of the workpiece (5).

16. The ring rolling machine according to any one of claims 10 to 13, characterized in that, The ring rolling machine is a radial ring rolling machine or a radial-axial ring rolling machine.

17. The ring rolling machine according to any one of claims 10 to 13, characterized in that, The alternating magnetic field has a frequency between 4 kHz and 10 kHz.

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