Rolling mill stand for rolling metal strip

Abstract

The present invention relates to a mill stand (100) for rolling metal strip (200), comprising: a small work roll (110) and a large work roll (120) arranged opposite each other, the small work roll and the large work roll together opening a roll gap for rolling the metal strip (200); an auxiliary roll (111) on which the small work roll (110) is supported, wherein the small work roll (110) has a smaller diameter than the auxiliary roll (111) and the auxiliary roll (111) has a smaller diameter than the large work roll (120). According to the invention, a support device (150) for the small work roll (110) and an adjustment device (160) for horizontally adjusting the support device (150) relative to the small work roll (110) are arranged.

Description

TECHNICAL FIELD

[0001] The invention relates to a rolling stand for rolling a metal strip, and to a rolling train having a plurality of rolling stands according to the invention arranged one after the other in the direction of material flow. BACKGROUND

[0002] The invention relates in particular to a rolling stand having an odd number of rolls, further in particular three, five or seven rolls. In contrast to conventional two-high stands, four-high stands or six-high stands having two, four or six rolls respectively, in the rolling stand according to the invention on either the upper side or the lower side of the metal strip to be rolled, the conventional upper work roll or lower work roll is replaced by a small work roll and an additional roll. Such rolling stands are basically known from the prior art.

[0003] Japanese patent application JP 2010075985 discloses a rolling stand having five rolls, wherein the upper work roll is in particular small, in particular smaller than the lower work roll. Arranging a work roll of smaller diameter shows the advantage that high-strength steels having a large deformation resistance can thereby be rolled more easily, since the required rolling force can be reduced due to the smaller work roll diameter.

[0004] Japanese patent application JP 61245904 A also discloses a mill stand with five rolls arranged vertically overlapping each other, wherein the upper work roll has a smaller diameter than the lower work roll. This Japanese patent application specifically recommends this stand configuration for asymmetrical rolling of electroplated steel sheets. Since the electroplated steel sheet has different deformation resistances on its upper and lower surfaces, it is recommended to use different work roll circumferential speeds to roll such a sheet, such as by using work rolls of different diameters at the same drive speed. The second upper work roll has the same diameter as a conventional work roll; that is, if the first and second work rolls are arranged vertically overlapping each other, they together have a greater height than a single conventional work roll. The work roll with the smaller diameter is arranged on the side of the electroplated material to be rolled that has greater deformation resistance; conversely, the work roll with the larger diameter is arranged on the side of the electroplated material that has less deformation resistance. The work roll with the smaller diameter can be oscillated relative to the conventional work roll with the larger diameter; in particular, the smaller work roll can oscillate outwards from the vertical force line. In other words, the smaller work rolls can be arranged either in the vertical force transmission direction or swung out, depending on the requirements; in the latter case, the mill stand can operate as a standard four-stand mill, where two opposing work rolls each have the same diameter. In this regard, the mill stand disclosed in Japanese Patent Application JP 61245904 A expands the possibilities of rolling. However, the switching between the two described types of roll planetary positions requires not only the smaller diameter work roll to swung in or out, but also the vertical movement of the two rolls arranged above the smaller work roll within the mill stand.

[0005] Furthermore, refer to European patent application EP 0 114 795 A. This application discloses a conventional four-high mill stand with a total of four rolls arranged in an overlapping manner, namely, two inner work rolls with the roll gap widened, an upper support roll arranged above the upper work roll, and a lower support roll arranged below the lower work roll. For the two work rolls that appear to have the same diameter, each is provided with a double-sided horizontal hydraulic support device, wherein support tiles are respectively pressed against the surface of one of the work rolls, and wherein lubricant is pumped into the gap between the support tiles and the respective work roll by means of a pump device. The disclosed horizontal support device is particularly used to improve the overall horizontal stiffness or stability of the stand, which is especially beneficial for cold rolling thin strips with high deformation resistance. Summary of the Invention

[0006] The objective of this invention is to improve a known mill stand with an odd number of rolls arranged in an overlapping manner, so as to effectively prevent lateral bending of the small work rolls.

[0007] This task is solved by a mill stand for rolling metal strip according to the invention. The mill stand has: a small work roll and a large work roll arranged opposite each other, the small work roll and the large work roll together opening a roll gap for rolling the metal strip; an auxiliary roll supporting the small work roll via the auxiliary roll, wherein the small work roll has a smaller diameter than the auxiliary roll; a support device for the small work roll that operates at least on one side in the horizontal direction; and an adjustment device for horizontally adjusting the support device relative to the small work roll; the auxiliary roll has a smaller diameter than the large work roll, the small work roll and the auxiliary roll are arranged in a replacement insert connected to each other and rotatable relative to each other, the total height of the replacement insert having the small work roll and the auxiliary roll at least partially corresponding to the diameter of the large work roll. Accordingly, the mill stand according to the invention is characterized by having a support device and an adjustment device for the small work roll, the support device operating at least on one side in the horizontal direction; the adjustment device for horizontally adjusting the support device relative to the small work roll.

[0008] Preferably, the support device supports the small working rollers not only on one side, but on both sides.

[0009] By installing the necessary support devices, lateral bending of the small work rolls is effectively prevented, thereby improving the overall rigidity of the mill stand with an odd number of rolls. Due to the stability of the additional rolls arranged between the small work rolls and the second support roll or the second intermediate roll, the efficiency required for the support devices to stabilize the entire mill stand is lower than the efficiency required to stabilize the work rolls in a conventional mill stand with four or six rolls arranged vertically and horizontally, in which the two work rolls each have the same diameter.

[0010] Within the meaning of this invention, the term "work roll" is understood as a roll that directly contacts the workpiece and performs the forming work.

[0011] The device is equipped with work rolls of different sizes. The work roll referred to in this application as the large work roll corresponds to the work roll typically used in practice.

[0012] When using a small work roll to replace the large work roll, an additional roll is always used in conjunction, resulting in a roll set with an odd number of rolls.

[0013] Within the framework of this description, the term "adjusting device" refers not only to a device, preferably hydraulically operated, for variably adjusting the support device, particularly its supporting tiles, relative to the small work roll, but also specifically to a static, i.e. non-variable, holding device for fixing the position of the support device on the small work roll.

[0014] According to the present invention, the size ratio is determined to be that the small work roll has a smaller diameter than the auxiliary roll and the auxiliary roll has a smaller diameter than the large work roll.

[0015] The mill stand according to the invention may alternatively have or not have support rolls and / or intermediate rolls.

[0016] In a first preferred variant embodiment, a first support roller for supporting a large work roll and a second support roller for supporting an additional roll are provided, wherein both support rollers have a larger diameter than the large work roll. Particularly preferred in this arrangement is that the two support rollers have the same diameter.

[0017] In a further variant embodiment, a first intermediate roll is provided between the large work roll and the first support roll, and a second intermediate roll is provided between the auxiliary roll and the second support roll, wherein the first intermediate roll has a diameter larger than the large work roll and smaller than the first support roll, and the second intermediate roll has a diameter larger than the auxiliary roll and smaller than the second support roll. Particularly preferred in this arrangement is that the two intermediate rolls have the same diameter.

[0018] Various driving concepts are feasible in this invention for driving the rolls of the rolling mill stand.

[0019] In one variant embodiment, the mill stand has only one drive unit for rotating the large work roll. This drive unit may optionally additionally drive an auxiliary roll. When driving both the large work roll and the auxiliary roll simultaneously, it is important to note that the drive unit drives both rolls in the same direction of rotation and, if necessary, at comparable speeds.

[0020] In a further variant embodiment, the mill stand has a drive mechanism for rotating the first support roll and / or the second support roll. It should be noted that when both the first and second support rolls are driven simultaneously, the drive mechanism drives both rolls in the same direction of rotation, respectively.

[0021] In a further variant embodiment, the mill stand has a drive mechanism for rotating the first intermediate roll and / or the second intermediate roll. It should be noted that when both the first and second intermediate rolls are driven simultaneously, the drive mechanism drives both rolls in the same direction of rotation, respectively.

[0022] Generally, the advantage here is that, in the case of an odd number of rolls in the mill stand according to the invention, it is ensured that the two work rolls that jointly open the roll gap work together without touching each other on the ground.

[0023] Advantageously, the small working roll and the auxiliary roll are rotatably supported in the replacement insert.

[0024] According to a further embodiment, the support device has at least one support tile for pressing against the small work roller at least on one side, preferably on both sides. A pump device is provided for pumping fluid into the gap between the at least one support tile and the small work roller. The support device is advantageously located inside the replacement insert. This saves space and is particularly significant because, according to the invention, the support device is provided only for the small work roller.

[0025] The fluid pumped into the gap, preferably in the form of a cooling lubricant, acts as a hydrostatic cushion and also effectively cools the small work roll. The gap dimensions and the stability of the horizontal support can be varied by setting the fluid pressure and / or by adjusting the fluid's volumetric flow rate. Setting and adjusting the pressure and / or flow rate are used here to establish optimal horizontal support.

[0026] Since the required replacement inserts only involve small work rolls and auxiliary rolls, the flatness adjustment mechanisms of all other rolls outside the replacement inserts, namely support rolls and / or intermediate rolls, can remain functional without alteration; this involves, for example, bending cylinders for bending rolls, continuously variable crown (CVC) adjustment devices for axial displacement, adjustment devices for horizontal displacement, or zone cooling devices.

[0027] Advantageously, the external geometry, particularly the overall height, of the replacement insert with the small work roll and auxiliary roll corresponds at least partially and largely to the external geometry, particularly the diameter, of the large work roll located on the opposite side, or the diameter of a conventional two-roll, four-roll, or six-roll mill stand. This allows for particularly easy implementation of the invention within a modern framework. In new equipment, deviations relative to the large work roll up to 30%, preferably up to 20%, are permissible. With the necessary replacement insert, the conversion from a conventional two-roll mill stand with two overlapping rolls, a four-roll mill stand with four overlapping rolls, or a six-roll mill stand with six overlapping rolls to the mill stand according to the invention with an odd number of rolls, a small work roll, and auxiliary rolls is very easy and rapid, because the replacement insert, based on its dimensions, fits well into existing mounting bases for conventional work roll assemblies. In this respect, the mill stand can be very flexibly expanded in terms of its rolling possibilities through the necessary replacement insert. This also applies to configurations that revert to traditional two-roll, four-roll, or six-roll stands.

[0028] This invention can also be used to extend rolling schemes in single-row or tandem stands, in unidirectional or reverse operation. When using a mill stand according to the invention with only one driven roll, the influence of the asymmetrical roll gap ratio (small and large work rolls with different diameters) on the microstructure must be considered. The effect on the microstructure of the strip to be rolled under so-called traction drive comes from the displacement of the flow boundary between the driven and unelectrified work rolls. This can be further actively influenced by setting the speed or torque of the individual drive. The horizontal offset of the small work roll and the offset of the entire insert or other rolls are set or adjusted according to the process model and / or by taking into account necessary parameters, especially the measured strip tension, rolling force, and / or rolling torque, by setting the displacement / movement of the support rolls.

[0029] Furthermore, the mill stand according to the invention achieves higher rolling speeds than conventional mill stands, especially compared to well-known multi-roll mill stands; thus, rolling speeds exceeding 800 m / min are possible, for example. Of course, for products other than thin strips made of high-strength steel, normal operating modes can still be performed within limitations. The mill stand according to the invention is particularly suitable for the cold rolling of high-strength thin metal strips.

[0030] By using a clamping device, the relative horizontal offset of the small working roller and the auxiliary roller of the replacement insert is adjusted so that the lateral force acting on the support tile is minimized or set within a range meaningful for the load. Here, in single-drive or dual-drive systems, the measured motor current can be used to calculate the horizontal force. This is not entirely possible in gear drives due to unknown torque distortion.

[0031] When the replacement insert is positioned above the metal strip: the roller gap friction is generally smaller on the upper side due to a large pool of cooling lubricant, so the risk of slippage from transmitting drive power through the lower side is smaller.

[0032] When the insert is positioned below the metal strip, only a small portion of the cooling lubricant exiting from the support tiles reaches the strip. A conventional cooling lubrication system or a system for purging the strip can be installed on the upper side, as is known.

[0033] For small, undriven work rolls, the reduction of roll gap friction can be achieved by applying additional cooling lubricant, applying concentrate / additive, or applying cooling lubricant with an increased concentrate / additive content.

[0034] The replacement plug-in can be integrated as a whole into a bending system or an axial / horizontal displacement system. Attached Figure Description

[0035] The invention and its technical field are further explained below with reference to the accompanying drawings. It should be noted that the invention should not be limited to the embodiments shown. In particular, unless explicitly stated otherwise, aspects of the subject matter explained in the drawings can be extracted and combined with other components and knowledge derived from this description and / or the drawings. It should be specifically noted that the drawings and, in particular, the scale shown are merely illustrative. The same reference numerals describe the same subject matter, and thus, explanations derived from other drawings may be referenced as supplementary if necessary. The drawings show:

[0036] Figure 1 Variant embodiments of the rolling mill stand according to the present invention;

[0037] Figure 2 Small work rolls and auxiliary rolls are arranged in various planetary positions on the mill stand according to the invention on the upper side of the metal strip; and

[0038] Figure 3 Small work rolls and auxiliary rolls are arranged in various planetary positions on the mill stand according to the invention on the underside of the metal strip. Detailed Implementation

[0039] exist Figure 1 The right half of the image shows a variant embodiment of a mill stand 100 according to the invention for rolling metal strip 200. The mill stand has a small work roll 110 and an auxiliary work roll 111 effectively connected thereto, as well as a large work roll 120. As per [reference to...] Figure 1 As can be seen, the small work roll 110 and the large work roll 120 widen the roll gap for rolling the metal strip 200. The auxiliary roll 111 has a larger diameter than the small work roll 110, but a smaller diameter than the large work roll 120 which is arranged opposite to the small work roll 110.

[0040] Advantageously, the sum of the diameters of the small work roll 110 and the auxiliary roll 111—in a vertically overlapping arrangement—largely corresponds to the diameter of the large work roll 120. This makes it easier to replace the conventional work roll, whose diameter is equivalent to the sum of the diameters of the two rolls 110, 111, especially when both are rotatably arranged in the replacement insert 130. The conventional work roll 140 and its fittings or bearing housing 141 are shown for comparison in the left half. According to the invention, the external geometry, especially the total height, of the replacement insert 130 having two rolls 110, 111 corresponds to the external geometry, especially the diameter, of the opposite work roll 120 and the conventional work roll 140. Thus, the simple replacement operation can be very simple and quick.

[0041] Ideally, equality is desired, although deviations may already exist due to wear zones on the inserted rolls. Furthermore, design flaws may also introduce deviations. A total of up to 20% upward and downward deviation is tolerable.

[0042] In addition Figure 1 As can be seen, the small working roller 110 is preferably supported horizontally on both sides by means of a horizontal support device 150 to prevent horizontal or lateral bending. For this purpose, the support device 150 is adjusted relative to the small working roller 110 by means of, for example, a hydraulically operated adjustment device 160. More precisely, not the entire support device 150, but only its support tiles 155 are arranged against the small working roller 110. Furthermore, a pump device 170 is arranged to pump fluid or cooling lubricant into the gap 175 between the support tiles 155 and the small working roller 110. Preferably, as Figure 1 As shown, this is done on both sides of the small work roll 110.

[0043] Figure 2 Various embodiments of the mill stand 100 according to the invention are shown in subfigures a) to i), wherein small work rolls 110, each supported by an auxiliary roll 111, are arranged above the metal strip 200 to be rolled. Embodiment a) is consistent with the preceding reference. Figure 1 The first embodiment described. This embodiment is characterized in that only the large work roll 120, arranged below the metal strip 200, is rotated in the direction indicated by the arrow. All other rolls of the mill stand 100, particularly the small work rolls 110, are not rotated. Unlike embodiment a), in embodiment b), both the large work roll 120 and the auxiliary roll 111, arranged below the metal strip 200, are rotated in the direction indicated by the arrow.

[0044] according to Figure 2 c) to Figure 2 Each of the embodiments in e) relates to a mill stand with five rolls. Compared to the foregoing embodiments, these embodiments additionally include a first support roll 180 and a second support roll 185. The first support roll 180 is in effective connection with the large work roll 120 and has a larger diameter than the large work roll. Conversely, the second support roll 185 is in effective connection with the auxiliary roll 111 and has a larger diameter than the auxiliary roll. The drive concepts of embodiments 2c) and 2d) are consistent here with the drive concepts of embodiments 2a) and 2b). For embodiment 2e), only the first support roll 180 can be driven to rotate in the direction of rotation indicated by the arrow, or only the second support roll 185, or both the first support roll 180 and the second support roll 185 can be driven to rotate simultaneously.

[0045] according to Figure 2 f) to Figure 2Each of the embodiments in i) relates to a rolling mill stand with seven rolls. (This is in contrast to the foregoing embodiments.) Figure 2 c) to Figure 2 Compared to embodiments e), these embodiments additionally include a first intermediate roller 190 and a second intermediate roller 195. The first intermediate roller 190 is arranged between the first support roller 180 and the large work roller 120 and has a diameter larger than the large work roller 120 and smaller than the first support roller 180. The second intermediate roller 195 is arranged between the second support roller 185 and the auxiliary roller 111 and has a diameter larger than the auxiliary roller 111 and smaller than the second support roller 185. The driving concepts of embodiments 2f) and 2g) are consistent with those of embodiments 2a) to 2d). For embodiments 2h) and 2i), the first support roller 180 can be driven in the direction of rotation indicated by the arrow, or alternatively, only the first intermediate roller 190, or only the second support roller 185, or alternatively, only the second intermediate roller 195, or both the first support roller 180 and the second support roller 185 can be driven in rotation simultaneously, or alternatively, both the first intermediate roller 190 and the second intermediate roller 195 can be driven in rotation simultaneously.

[0046] Figure 3 Various embodiments of the mill stand 100 according to the invention are shown in subfigures a) to i), wherein small work rolls 110, each supported by an auxiliary roll 111, are arranged below the metal strip 200 to be rolled. For this purpose, previously referred to... Figure 2 The statements made regarding the embodiments shown therein are in accordance with Figure 3 The same or similar implementations also apply.

[0047] The combination of features defined in the independent claims does not limit the invention, and any other combination of any particular feature among all the disclosed individual features can also define the invention. This means that, in principle, almost every individual feature in the independent claims can be deleted or replaced by at least one of the individual features disclosed elsewhere in this application. In this regard, the independent claims should be understood as merely a first drafting attempt of the invention.

[0048] Reference Signs

[0049] 100 rolling mill stands

[0050] 110 Small Working Roller

[0051] 111 Additional Roller

[0052] 120 large work roll

[0053] 130 Replacement Plugin

[0054] 140 Traditional Work Roller

[0055] 141 Assembly / Bearing Housing

[0056] 150 Hydraulic support device

[0057] 155 Supporting tiles

[0058] 160 Adjustment device

[0059] 170 Pump unit for cooling lubricant

[0060] 175 gap

[0061] 180 First support roller

[0062] 185 Second support roller

[0063] 190 First intermediate roll

[0064] 195 Second Intermediate Roll

[0065] 200 metal strip

Claims

1. Rolling mill stand (100) for rolling a metal strip (200), the rolling mill stand having: a small work roll (110) and an oppositely arranged large work roll (120), which together span a roll gap for rolling a metal strip (200); an additional roll (111) via which the small work roll (110) is supported, wherein the small work roll (110) has a smaller diameter than the additional roll (111); a support device (150) for the small work roll (110) which acts at least unilaterally in horizontal direction; and an adjustment device (160) for horizontally adjusting the support device (150) relative to the small work roll (110); characterized in that the additional roll (111) has a smaller diameter than the large work roll (120), the small work roll (110) and the additional roll (111) are arranged in succession and rotatably relative to each other in a replacement insert (130), the total height of the replacement insert (130) with the small work roll (110) and the additional roll (111) corresponds at least partially to the diameter of the large work roll (120), wherein the total height of the replacement insert (130) with the small work roll (110) and the additional roll (111) deviates from the diameter of the large work roll (120) by up to 30%.

2. Rolling mill stand (100) according to claim 1, characterized in that the total height of the replacement insert (130) with the small work roll (110) and the additional roll (111) deviates from the diameter of the large work roll (120) by up to 20%.

3. Rolling mill stand (100) according to claim 1 or 2, characterized in that the rolling mill stand is provided with a first backup roll (180) for supporting the large work roll (120) and a second backup roll (185) for supporting the additional roll (111), wherein both backup rolls (180, 185) have a larger diameter than the large work roll (120).

4. Rolling mill stand (100) according to claim 3, characterized in that both backup rolls (180, 185) have the same diameter.

5. Rolling mill stand (100) according to claim 3, characterized in that a first intermediate roll (190) is provided which is arranged between the large work roll (120) and the first backup roll (180), wherein the first intermediate roll (190) has a larger diameter than the large work roll (120) and a smaller diameter than the first backup roll (180); and a second intermediate roll (195) is provided which is arranged between the additional roll (111) and the second backup roll (185), wherein the second intermediate roll (195) has a larger diameter than the additional roll (111) and a smaller diameter than the second backup roll (185). both intermediate rolls (190, 195) have the same diameter.

6. Rolling mill stand (100) according to claim 5, characterized in that the rolling mill stand is provided with:

7. The rolling stand (100) according to claim 5, characterized in that a drive device for rotationally driving the large work roll (120); or a drive device for rotationally driving the first backup roll (180) and / or the second backup roll (185); or a drive device for rotationally driving the first intermediate roll (190) and / or the second intermediate roll (195). the drive device is additionally used for rotationally driving the additional roll (111). ​ 8. Rolling mill stand (100) according to claim 7, characterized in that ​ 9. Rolling mill stand (100) according to claim 8, characterized in that In the event of driving the large work roll (120) and additionally driving the additional roll (111), the drive device rotates both rolls (111, 120) in the same rotational direction, respectively.

10. Rolling mill stand (100) according to claim 8, characterized in that In the event of driving the large work roll (120) and additionally driving the additional roll (111), the drive device rotates both rolls (111, 120) in the same rotational direction and at a corresponding rotational speed, respectively.

11. Rolling mill stand (100) according to claim 7, characterized in that In the event of driving the first backup roll (180) and the second backup roll (185), the drive device rotates both backup rolls (180, 185) in the same rotational direction, respectively.

12. Rolling mill stand (100) according to claim 7, characterized in that In the event of driving the first intermediate roll (190) and the second intermediate roll (195), the drive device rotates both intermediate rolls (190, 195) in the same rotational direction, respectively.

13. Rolling mill stand (100) according to claim 1 or 2, characterized in that The support device (150) has at least one support tile (155) for pressing at least unilaterally against the small work roll (110); and the rolling mill stand is provided with a pump device (170) for pumping fluid into a gap (175) between the at least one support tile (155) and the small work roll (110).

14. Rolling mill stand (100) according to claim 5, characterized in that There is provided at least one flatness adjustment mechanism for the small work roll (110) and the additional roll (111), the backup rolls (180, 185) and / or the intermediate rolls (190, 195) assigned to the replacement insert (130).

15. Rolling mill stand (100) according to claim 1 or 2, characterized in that The rolling mill stand (100) is a single-stand mill stand or a tandem mill stand operated in one direction or in reverse.

16. Rolling mill stand (100) according to claim 1 or 2, characterized in that The rolling mill stand (100) is a cold rolling mill stand for cold-rolling a metal strip (200).

17. A tandem rolling train having a plurality of rolling stands (100) arranged one after the other in the direction of material flow, characterized in that The rolling mill stand (100) is configured according to any one of the preceding claims. The rolling mill stand (100) is a cold rolling mill stand for cold-rolling a metal strip (200).

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