Method for heating a steel intermediate strip when producing a flat steel strip

Abstract

The invention relates to a method for heating, in particular reheating, an intermediate strip (2) when producing a flat strip, wherein the intermediate strip (2) is heated using induction module heads (12) of induction modules (10) of an induction furnace (1), in particular of a rolling mill, preferably of a steel strip production system, and the induction module heads (12) are mechanically positioned according to at least one current parameter of the intermediate strip (2) at / in the induction furnace (1).

Description

[0001] Description

[0002] Method for heating a steel intermediate strip during the production of a steel flat strip

[0003] The invention relates to a method for heating, in particular reheating, an intermediate strip during the production of a flat strip. Furthermore, the invention relates to a system control system for an induction furnace, a rolling mill, or a steel strip production plant, in particular for continuous strip production. Furthermore, the invention relates to an induction furnace, a rolling mill, or a steel strip production plant, in particular for continuous strip production.

[0004] In a steel strip production plant, for example, for endless strip production (ESP), an induction furnace is used in a rolling mill of the steel strip production plant to reheat a (steel) intermediate strip of a (steel) flat strip to be formed using a casting-rolling process. This induction furnace is located, for example, between a high-reduction mill (HRM) with, for example, two to four, and in particular three, rolling stands, and a finishing mill (EM) with, for example, four to seven, and in particular five, rolling stands.

[0005] The quality of a finished flat strip depends, in addition to a multitude of other mutually influencing factors, on the heating or reheating of an intermediate strip in an induction furnace. Particularly for thinner intermediate strips, so-called transverse field induction modules (transversal flux) in the induction furnace have proven to be an efficient and therefore suitable solution for a rolling mill in a steel strip production plant. The rolling mill can, as above, comprise a number of rolling mills. Furthermore, the quality of the finished flat strip depends on a uniform temperature distribution of the intermediate strip, particularly at a rear longitudinal end of the induction furnace in the production direction. The more uniform the current temperature distribution is there along a surface line or along a cross-section in the transverse direction of the intermediate strip, the better the quality of the finished flat strip can be.The transverse direction is, of course, perpendicular to the two edges of the intermediate strip. - It is an object of the invention to ensure correct heating, in particular correct reheating, of an intermediate strip during the production of a flat strip.

[0006] EP 2 287 345 A1 teaches a method for controlling and / or regulating an induction furnace for a rolling mill, wherein an electrical control of the induction coils of an induction furnace is shown.

[0007] JP S 62 013 526 A discloses a method for controlling the temperature of an inductively heated furnace for heating slabs using a computer-based control system.

[0008] JP 2007 237 240 A discloses a mechanical adjustment of induction coils.

[0009] The object of the invention is achieved by a method for heating, in particular reheating, an intermediate strip during the production of a flat strip; by means of a system control for an induction furnace, a rolling mill or a steel strip production plant, in particular for endless strip production; and by means of an induction furnace, a rolling mill or a steel strip production plant, in particular for endless strip production. - Advantageous developments, additional features and / or advantages of the invention emerge from the dependent claims and the following description. Transverse field induction modules of an induction furnace for e.g. a rolling mill of a steel strip production plant are installed and controlled in pairs in order to make the power input into the intermediate strip as uniform as possible. A pair of transverse field induction modules is installed as follows.

[0010] Through a closed end region of a first induction module head of a transverse field induction module, a first

[0011] Band edge (edge ​​region) and the second band edge (edge ​​region) can be heated by the closed end region of a second induction module head of a transverse field induction module. The same applies to the open middle regions of the transverse field

[0012] Induction modules; i.e., an open center region of the induction module head of the first transverse-field induction module lies diagonally to the open center region of the induction module head of the second transverse-field induction module with respect to an induction furnace centerline. See also Figs. 3 to 7 (closed end regions: 13, open center regions: 14).

[0013] During investigations into the quality of finished flat strips, it was found that a symmetrical temperature distribution of an intermediate strip (Fig. 2) at the end of the induction furnace running in the direction of production, i.e. at the rear longitudinal end, represents a good compromise as a precursor to a uniform temperature distribution, which is currently not practicable in a running intermediate strip. (Such an essentially uniform temperature distribution at a strip edge is represented by the solid temperature distribution in Fig. 1, where only a single induction module head was active.)

[0014] Further investigations have shown that due to a mechanical adjustment of the induction module heads relative to the induction furnace centerline, the actual adjustment of the induction module heads to an intermediate strip running through the rolling mill often deviates from the intended adjustment. This occurs when the intermediate strip centerline does not coincide (parallel) with the induction furnace centerline. Contrary to previous assumptions, it has been shown that such parallel deviations in both transverse directions, as well as angular deviations, are the rule rather than the exception.

[0015] It is therefore important that the induction modules are correctly positioned with respect to the intermediate strip in order to achieve a uniform temperature distribution of the intermediate strip on its surface in the transverse direction, e.g. thought of as a transverse line, i.e. also across its cross-section. - In the method according to the invention, the intermediate strip is heated by induction module heads of induction modules of an induction furnace, in particular a rolling mill, preferably a steel strip production plant, in particular for endless strip production, wherein the induction module heads are mechanically positioned on / in the induction furnace according to at least one current, i.e. of course also actual, parameter of the intermediate strip. - For the positioning of the induction module heads, at least one further parameter can of course be used if necessary.

[0016] According to the at least one parameter of the intermediate belt, the induction module heads of the induction furnace are adjusted in such a way that at least one position in / on the induction furnace, in the transverse direction on / in the intermediate belt with respect to the intermediate belt center line, a thermal energy distribution (e.g. a temperature distribution) of the moving intermediate belt that becomes symmetrical over time is established. This means that the thermal energy distribution of the moving intermediate belt at this at least one position is observed. The thermal energy distribution or a symmetry of the thermal energy distribution is independent of deviations of the intermediate belt center line from an induction furnace center line.

[0017] According to the at least one parameter of the intermediate strip, an attempt can be made, or is intended, to maintain this heat energy distribution of the intermediate strip in its preliminary symmetry or to further symmetrize this preliminary symmetry by setting up induction module heads in the chronological sequence at at least one position in / on the induction furnace. Furthermore, an attempt can be made, or is intended, to even out this heat energy distribution of the intermediate strip in the transverse direction on / in the intermediate strip. Furthermore, an attempt can be made, or is intended, to match a heat energy of a strip edge of the intermediate strip to a heat energy of the intermediate strip center line.The parameter of the intermediate strip can essentially reflect a current (actual) statement about the current (actual) intermediate strip at / in the induction furnace and / or at / in the rolling mill. Furthermore, the parameter of the intermediate strip cannot represent a merely general statement about the induction furnace itself and / or the rolling mill itself. - This means, for example, that the parameter of the intermediate strip does not reflect a merely local or global statement about the induction furnace itself and / or the rolling mill itself. The parameter can represent a current statement about an interaction of the intermediate strip with the induction furnace itself and / or the rolling mill itself. Furthermore, the parameter can represent a current statement about the intermediate strip at / in the induction furnace and / or a current statement about the intermediate strip itself.

[0018] The parameter of the intermediate strip cannot reflect an exclusively geometric statement about the induction furnace itself and / or the rolling mill itself, or any transverse limitation of the intermediate strip in the induction furnace itself and / or in the rolling mill itself. This naturally also applies to any other characterization of the intermediate strip essentially exclusively by the induction furnace itself and / or the rolling mill itself. - The parameter of the intermediate strip can reflect a geometric position of the intermediate strip within the rolling mill and / or the induction furnace, and / or a heat energy distribution of the intermediate strip in the transverse direction of the intermediate strip on / in the rolling mill and / or on / in the induction furnace.

[0019] It is important here that the distance between the induction modules and the edge of the intermediate strip is set correctly in order to achieve, if possible, a symmetrical and, if possible, uniform (similar values ​​and / or no point of discontinuity (high gradient, kink)) heat energy distribution of the intermediate strip on its surface across its width (thought of as a width line) or across a cross-section. - The actual adjustment of an induction module head with respect to a strip edge or edges of the intermediate strip is not known precisely enough in the prior art. The next measuring positions for the intermediate strip are located well before and / or well after the induction furnace and / or the rolling mill.

[0020] The parameter of the intermediate belt can reflect the inter-belt center line in the induction furnace. Another value, in particular another current measured value, can be included in the parameter of the intermediate belt. Furthermore, a current thermal energy distribution of the intermediate belt can be included in the parameter of the intermediate belt. Furthermore, the parameter of the intermediate belt can essentially exclusively represent the inter-belt center line. Furthermore, the inter-belt center line can be detected by center line detection. Such center line detection works, for example, with at least one lateral guide roller, a center line measurement, an edge measurement, image processing, a vision device / system, etc.

[0021] The intermediate strip centerline in the induction furnace can be determined from the current positioning of exactly / at least one, exactly / at least two, or exactly / at least four side guide rollers against the intermediate strip. By positioning a single side guide roller, together with a known width of the intermediate strip in the transverse direction, a point / section of a centerline of the intermediate strip in the induction furnace can be determined at a position of the side guide roller. With (at least) two side guide rollers arranged offset in the longitudinal direction of the induction furnace, a centerline in the induction furnace can be determined in this way.

[0022] This can be extended to side guide roller pairs, whereby a point / section of a center line of the intermediate strip in the induction furnace can be determined at a position of the side guide roller pair without a known width of the intermediate strip. With (at least) two side guide roller pairs arranged offset in the longitudinal direction of the induction furnace, a center line in the induction furnace can be determined in this way without a known width of the intermediate strip.

[0023] The current setting of a side guide roller can be obtained from / received from a force control of the side guide roller. The current setting of the side guide rollers via force control is therefore used to detect the intermediate belt centerline. The intermediate belt centerline detected via the side guide rollers is then forwarded to a system control (automation) of the induction furnace. From the current setting of the side guide rollers, a parallel and / or angled current offset of the intermediate belt centerline relative to the induction furnace centerline can be determined.

[0024] The parameter of the intermediate strip can reflect a heat energy distribution of the intermediate strip at / in the induction furnace. Another value, in particular another current measured value, can be included in the parameter of the intermediate strip. Furthermore, a current intermediate strip center line can be included in the parameter of the intermediate strip. Furthermore, the parameter of the intermediate strip can essentially exclusively represent the heat energy distribution of the intermediate strip. Furthermore, the heat energy distribution of the intermediate strip can be detected by a temperature determination device, in particular a temperature scanner.

[0025] The current thermal energy distribution of the intermediate strip can be determined in the transverse direction. From the thermal energy distribution, a current trend line can then be determined, which reflects the current degree of symmetry of the thermal energy distribution of the intermediate strip in the transverse direction. Based on this current trend line, the induction module heads of the induction furnace can be adjusted such that the current degree of symmetry of the thermal energy distribution of the intermediate strip in the transverse direction becomes symmetrical or at least not asymmetrical.

[0026] This involves, for example, comparing an earlier trend line with the current trend line, or comparing the current trend line with an ideal trend line such that the current trend line should show at least a uniformly symmetrical heat energy distribution or an improved symmetry of the heat energy distribution. - The heat energy distribution of the intermediate band can be determined, for example, by temperature determination, in particular a temperature scanner, as a temperature distribution of the intermediate band.

[0027] In embodiments, an incoming, current heat energy distribution of the intermediate strip in the transverse direction can be determined before the actual (at / in the beginning of the induction furnace) and / or in the front (front half of the induction furnace) induction furnace. From this heat energy distribution, a required electrical power of the induction furnace, a required electrical power distribution within the induction furnace and / or a required position of induction module heads in the transverse direction can be determined. Furthermore, the induction module heads can preferably initially be adjusted in such a way that an asymmetry of a temperature distribution of the incoming intermediate strip entering the induction furnace is compensated. The method looks a certain time into the future and then, if necessary, adjusts induction module heads accordingly, possibly modified by the method.

[0028] In embodiments, an outgoing, current heat energy distribution of the intermediate strip in the transverse direction can be determined in the rear (rear half of the induction furnace) and / or behind the actual (in / at the end of the induction furnace) induction furnace. From this heat energy distribution, a current trend line can be determined which reflects a current degree of symmetry of the heat energy distribution of the intermediate strip in the transverse direction. The induction module heads can then be adjusted on the basis of the trend line in such a way that an asymmetry of a temperature distribution of the outgoing intermediate strip is compensated. In this case, an incoming, current heat energy distribution of the intermediate strip in the transverse direction can be taken into account. This means that those induction module heads which are positioned above / below a colder strip edge are moved further in the direction of this strip edge.

[0029] The method can be operated in such a way that a current trend line of a current heat energy distribution of the intermediate band approaches a desired (good to essentially optimal) trend line (target trend line). For this purpose, the relevant induction module heads above / below the intermediate band are adjusted accordingly. The relevant trend line can be a linear, a non-linear, a composite, etc. trend line. - The method can be designed as a control method or a control method (closed loop control). The induction modules can be designed as transverse field induction modules. This naturally also means that the induction module heads are designed as transverse field induction module heads.

[0030] The plant control according to the invention is designed such that a method according to the invention can be carried out and / or is carried out by the plant control. The plant control has a plant control device and the connections required therefor. - The induction furnace according to the invention, the rolling mill according to the invention or the steel strip production plant according to the invention has a plant control according to the invention. Furthermore, a method according to the invention can be carried out and / or be carried out by the induction furnace according to the invention, the rolling mill according to the invention or the steel strip production plant according to the invention. The invention is explained in more detail below using exemplary embodiments with reference to the attached schematic drawing which is not to scale.Sections, elements, parts, units, components and / or schemes which have an identical, unique or analogous design and / or function are identified with the same reference symbols in the description of the figures (see below), the list of reference symbols, the patent claims and in the figures (Fig.) of the drawing. A possible alternative not explained in the description of the invention (see above), not shown in the drawing and / or not exhaustive, a static and / or kinematic reversal, a combination, etc. to the embodiments of the invention or of a component, scheme, unit, part, element or section thereof, can also be found in the list of reference symbols and / or the description of the figures.

[0031] In the invention, a feature (section, element, part, unit, component, function, size, etc.) can be positive, i.e. present, or negative, i.e. absent. In this specification (description (description of the invention (see above), description of the figures (see below)), list of reference symbols, claims, drawing), a negative feature is not explicitly explained as a feature unless it is important for it to be absent according to the invention. This means that the invention actually made and not one constructed by the prior art consists in omitting this feature.

[0032] A feature of this specification can be applied not only in a specified manner and / or form, but also in a different manner and / or form (isolation, combination, replacement, addition, uniqueness, omission, etc.). In particular, it is possible to replace, add, or omit a feature in the patent claims and / or the description using a reference symbol and a feature assigned to it, or vice versa, in the description, the list of reference symbols, the patent claims, and / or the drawing. Furthermore, a feature in a patent claim can be interpreted and / or specified in more detail in this way.

[0033] The features of the description can also be interpreted as optional features (in view of the (initially usually unknown) prior art); i.e. each feature can be understood as an optional, arbitrary or preferred, i.e. as a non-binding, feature. In this way, a feature, possibly including its periphery, can be extracted from an embodiment, whereby this feature can then be transferred to a generalized inventive concept. The absence of a feature (negative feature) in an embodiment shows that the feature may be optional with regard to the invention (to a person skilled in the art). Furthermore, if a species term is used for a feature, a generic term for the feature can also be read along with it (possibly further hierarchical division into subgenus, etc.), whereby a generalization of the feature is possible, e.g. taking into account equal effect and / or equivalence.

[0034] In the purely exemplary and schematic figures of the drawing: Figures 1 and 2 each show a temperature distribution of an intermediate strip in a steel strip production plant, after reheating of the intermediate strip by a single transverse field induction module (Figure 1) and by a plurality of paired transverse field induction modules (Figure 2) of an induction furnace of a rolling mill, Figures 3, 4 and 8 show two-dimensional, highly schematic plan views of a prior art, wherein the induction module heads of induction modules relate to a center line of the rolling mill and a center line of the intermediate strip deviates from the rolling mill center line parallel (Figure 4) or at an angle (Figure 5), Figures5 and 7 show, in two-dimensional, highly schematic plan views, exemplary embodiments of a first embodiment of the invention, wherein induction module heads relate to a center line of the intermediate strip and the intermediate strip center line deviates from the rolling mill center line in parallel (Fig. 5) or at an angle (Fig. 7), and Figs. 8, 9 and 10 show the second embodiment of the invention, wherein a trend line of a symmetrical temperature distribution of the intermediate strip (Fig. 9) is controlled or regulated by a trend line of an asymmetrical temperature distribution of the intermediate strip (Fig. 8) and a corresponding adjustment of induction module heads (Fig. 10).

[0035] The invention is explained in more detail below using exemplary embodiments of two embodiments (first embodiment: Figs. 5 and 7, second embodiment: Figs. 8 to 10) of methods for heating, in particular reheating, a (steel) intermediate strip 2 in an induction furnace 1 (also referred to as an induction heater 1) during the production of a (steel) flat strip in a rolling mill of a steel strip production plant, in particular for endless strip production. Although the invention is described and illustrated in more detail by preferred exemplary embodiments, the invention is not limited by the disclosed exemplary embodiments, but is of a more fundamental nature.

[0036] Other variations can be derived from this and / or from the above (description of the invention) without departing from the scope of the invention. The invention is generally applicable to induction furnaces, particularly in the field of steel production, preferably for producing a flat strip (see above). The drawings depict only those spatial sections of an object of the invention that are necessary for an understanding of the invention.

[0037] The explanation of the invention with reference to the drawings below refers to a longitudinal direction Lr and a transverse direction Qr. The longitudinal direction Lr corresponds to the main extension direction of the intermediate strip 2 (as well as a finished flat strip), the induction furnace 1, the rolling mill, and, if applicable, the steel strip production plant, and the transverse direction Qr is perpendicular to the longitudinal direction Lr and lies in the horizontal plane of the intermediate strip 2 (as well as the finished flat strip).

[0038] An induction furnace centerline M z is the straight line parallel to the longitudinal direction Lr, which represents the center line M of the induction furnace 1 or the rolling mill. An intermediate strip center line M z is the straight line which, mainly parallel to the longitudinal direction Lr, represents the center line M of the intermediate strip 2, particularly in the induction furnace 1 or in the rolling mill. In this case, the intermediate strip center line M z with respect to the induction furnace center line M z essentially parallel, offset or angled (small angles).

[0039] Due to the concept (cf. also Figs. 3 and 4), in an induction furnace 1, an induction module head 12 (coil current I) of a single transverse field induction module 10 results in one-sided local overheating of a (first) strip edge 22 (edge ​​region 22) of an intermediate strip 2 (Fig. 1, overheating on the left). This overheating is caused by eddy currents due to an open central region 14 of the induction module 10. The overheating of this first strip edge 22 is essentially independent of the position of this induction module head 12 relative to the intermediate strip 2 due to the geometric expansion of the induction module head 12 in the transverse direction Qr, because this induction module head 12 projects beyond this first strip edge 22.

[0040] See also the temperature distributions T zi (dotted) , T Z 2 (solid), T z3(dashed) which illustrate a dependence of the temperature of the intermediate strip 2 on a position of the induction module head 12 in the transverse direction Qr above the intermediate strip 2. Here, the temperature distribution T zi an induction module head 12, which projects beyond the second strip edge 22 (edge ​​region 22) opposite the first strip edge 22 (approximately +20 mm for a width of the intermediate strip 2 in the transverse direction Qr of approximately 1,200 mm). Furthermore, the temperature distribution T Z 2 an induction module head 12 in the correct position with respect to this second band edge 22. And the temperature distribution T Z3 represents an induction module head 12 which does not reach far enough to the second band edge 22 (approx. -20mm in the above example).

[0041] This means that the second band edge 22 opposite the first band edge 22 (Fig. 1, open central section 14) in the transverse direction Qr either heats up essentially correctly (for paired induction modules 10; cf. Fig. 1, solid line T Z 2) . Or if the induction module head 12 does not reach this band edge 22, underheating occurs (see Fig. 1 right, dashed line T z3 ) . And if the induction module head 12 extends beyond this band edge 22, one obtains an overheating analogous to that of an open central area 14 (cf. Fig. 1 right, dotted line T zi ) .

[0042] To counteract this and ideally achieve a symmetrical temperature distribution T z (analogous to heat energy distribution T z) of the intermediate strip 2 (cf. Fig. 2), induction modules 10 are installed in pairs (see Figs. 3 to 7). Thus, each strip edge 22 of the intermediate strip 2 passes both a closed end region 13 and an open middle region 14 of two induction module heads 12 arranged directly adjacent to one another of two induction modules 10 or a plurality of such pairs (cf. Fig. 3: five such pairs). Thus, the strip edges 22 of the intermediate strip 2 are heated essentially equally (cf. Fig. 2). In this case, an electrical power input into the intermediate strip 2 by means of the induction module heads 12 is essentially symmetrical. The distance between an induction module head 12 and the intermediate strip 2, i.e., its two strip edges 22, 22, significantly influences the temperature distribution T zof the intermediate strip 2 across its width, e.g., as a line in the transverse direction Qr in Figs. 1 and 2. Fig. 1 shows how the distance of an induction module 10 to the two strip edges 22, 22 of the intermediate strip 2 affects a power input (vertical axis: temperature distribution T z , e.g. in the form of a line power density, by specifying a temperature, etc.) into the intermediate strip 2 over a width (right axis: left strip edge 22 after the induction furnace center line M z to the right band edge 22) of the intermediate band 2 in the transverse direction Qr.

[0043] The further an induction module head 12 is from its outer band edge 22 (cf. the upper induction module heads 12 in Fig. 4), the lower the power input and subsequently the temperature there will be (cf. the temperature distribution T z of the intermediate band 2 in Fig. 4). To align the two band edges 22, 22 with respect to an intermediate band center line Mz To ensure uniform heating, the induction modules 10 are always installed in pairs. See Fig. 2 on the right, which shows the result of an electrical power input when several induction modules 10 are connected in pairs.

[0044] Here, a first induction module head 12 heats a first strip edge 22 with its open central region 14 and the second strip edge 22 opposite it in the transverse direction Qr with its closed end region 13; see, for example, the induction module head 12 on the far left in Fig. 3. Antiparallel to this, a second induction module head 12 heats the second strip edge 22 with its open central region 14 and the first strip edge 22 opposite it in the transverse direction Qr with its closed end region 13; see, for example, the induction module head 12 on the far left in Fig. 3 to the right of the induction module head 12. In the prior art, a mechanical adjustment of the individual transverse field induction modules 10 is carried out absolutely relative to an induction furnace center line M (see Fig. 3). zof the rolling mill, in the example mentioned above, the induction furnace center line Mj between the high-reduction rolling mill and the finishing rolling mill. However, the intermediate strip center line M z of the intermediate strip 2 is not always on the induction furnace center line Mj, see Fig. 4. However, on this basis of the induction furnace center line Mj, the transverse field induction modules 10 and their induction module heads 12 are positioned in the prior art.

[0045] If the interligament center line M z from the induction furnace center line M z off, see Fig. 4 , to which the induction module heads 12 refer, the asymmetric temperature distributions T discussed above occur. z at the strip edges 22 of the intermediate strip 2 at the exit of the induction furnace 1 . The asymmetric temperature distribution T z( Fig . 4 far right ) can subsequently lead to product quality problems as well as process stability problems .

[0046] This problem can be solved by at least one of the following measures: - The actual or current inter-band centerline M z is detected and used for the horizontal adjustment of induction modules 10 or their induction module heads 12 (center line detection). By adjusting the lateral guide rollers 30 to the intermediate belt 2, e.g., by means of a force control, the current intermediate belt center line M z of the intermediate band 2. Additionally or alternatively, the current intermediate band center line M z can also be detected by another suitable centerline detection (other device or apparatus on the intermediate belt 2, image processing, vision device / system, etc.).

[0047] The actual or current, particularly horizontal, inter-band center line M z of the intermediate belt 2 is subsequently passed on to a system control (automation), e.g. of the induction furnace 1. This sets the individual induction modules 10 or their induction module heads 12 according to the recorded and passed on intermediate belt center line M z This allows the induction modules 10 or their induction module heads 12 to be adjusted depending on the current intermediate belt center line M z and thus a symmetrical temperature distribution T z even with deviations from the center line M z of the intermediate band 2 from the center line M z the rolling mill (see Fig. 5, far right).

[0048] This allows deviations of the intermediate belt 2 in the transverse direction Qr (see Fig. 5, transverse direction deviation) as well as angular deviations of the intermediate belt 2 with respect to the intermediate belt center line M z (see Fig. 7, angle deviation) can be compensated. - Figs. 3 to 7 essentially show a run (arrow, intermediate belt center line M z ) of the intermediate belt 2 relative to the induction furnace center line M z , a position of the induction module heads 12 and a temperature distribution T z (far right) of the intermediate belt 2 at the exit of the induction furnace 1.

[0049] Figures 3 and 4 represent the state of the art. Initially (Figure 3), the intermediate strip 2 runs in the center of the induction furnace 1, e.g., the rolling mill. The induction module heads 12 are positioned symmetrically to a strip path of the intermediate strip 2 (induction furnace-proof). The current position corresponds (randomly) to the desired or pre-calculated position, since the intermediate strip center line M z with the induction furnace center line M z This results in a symmetrical temperature distribution T z (Fig. 3 far right) .

[0050] In Fig. 4, the intermediate belt 2 does not run in the middle of the induction furnace 1. The intermediate belt center line M z is not known to a plant control system. The induction module heads 12 refer to the induction furnace center line M z, whereby the induction module heads 12 are asymmetrically positioned to the intermediate belt 2. The pre-calculated position does not correspond to a current position, since the intermediate belt center line M z not equal to the induction furnace center line M z This results in an asymmetric temperature distribution T z a .

[0051] In Fig. 5, the intermediate belt 2 also does not run in the middle of the induction furnace 1. The intermediate belt center line M z However, it is currently known by adjusting the lateral guide rollers 30 to the intermediate belt 2. This means that by adjusting the lateral guide rollers 30, the current intermediate belt center line M z determine .

[0052] The induction module heads 12 can now focus on the intermediate belt center line M zand are adjusted accordingly. The induction module heads 12 are now symmetrical to the intermediate belt 2 and no longer symmetrical to the induction furnace center line M z The calculated setting corresponds to the current setting, since the intermediate belt center line M z is crucial for positioning the induction module heads 12 on the intermediate strip 2. This results in a symmetrical temperature distribution T z of the intermediate belt 2 ( Fig . 5 far right ) .

[0053] In Fig. 6 (state of the art), the intermediate belt 2 does not run in the center of the induction furnace 1, but at an angle to it. The intermediate belt center line M z is unknown. The induction module heads 12 refer to the induction furnace center line M z, whereby the induction module heads 12 are asymmetrically positioned to the intermediate belt 2. The calculated position does not correspond to the actual position, since the intermediate belt center line M z not equal to the induction furnace center line M z This results in an asymmetric temperature distribution T z (Fig. 6, far right). In Fig. 7, the intermediate belt 2 also does not run in the center of the induction furnace 1, but again at an angle to it. The intermediate belt center line M z is known by adjusting the side guide rollers 30. The induction module heads 12 can now be aligned with the intermediate belt center line M z and are adjusted accordingly. The induction module heads 12 are now adjusted symmetrically to the intermediate belt 2. The calculated adjustment corresponds to the current adjustment, since the intermediate belt center line M zis crucial for positioning the induction module heads 12 on the intermediate strip 2. This results in a symmetrical temperature distribution of the intermediate strip 2 T z ( Fig . 7 right ) .

[0054] Furthermore, see Fig. 8 to 10, alternatively or additionally at the beginning, in a middle and / or end of the induction furnace 1 (Fig. 10) the current temperature distribution T z of the intermediate strip 2, for example, by a temperature detector, in particular a temperature scanner 40. This temperature distribution T z is used to adjust induction module heads 12 hori zontally by means of a control method or a closed loop control method and to determine the temperature distribution T z If it is recognized that the temperature distribution T zon one side of the intermediate strip 2 deviates from a standard , the induction module heads 12 are adjusted in such a way that a symmetrical and , if possible , uniform temperature distribution T z is received .

[0055] Fig. 8 shows such a deviation in the form of a with respect to the interband center line M z asymmetric temperature distribution T z of the intermediate band 2 along a line ( transverse axis : 22 to M z according to 22 ) in the transverse direction Qr on the surface of the intermediate strip 2 . From this temperature distribution T z A trend line Tr, in this case a linear trend line Tr, can be determined or calculated. The trend line Tr can be determined or calculated in many different ways. Simple forms include, for example, connecting the absolute minima or the absolute maxima of the temperature distribution T zof the intermediate band 2 . Furthermore, a possibly weighted average of two such connecting lines can be used as a trend line Tr . In this case, the areas of the intermediate band 2 that terminate at the band edges 22 can be given special weighting. Higher-order trend lines Tr, e.g., non-linear trend lines Tr, are of course also applicable.

[0056] By means of the control method or the regulation method, a horizontal alignment of induction module heads 12 is now changed in such a way that the trend line Tr lies as close as possible to a predetermined essentially good to optimal solution, also represented by a trend line Tr (Fig. 9). In the present case, in the example of the linear trend lines Tr shown, a gradient of the essentially good to essentially optimal trend line Tr is zero (trend line Tr essentially parallel to the right-hand axis). The current dividing line Tr should approach this gradient and coincide with it if possible.

[0057] For this purpose, it is of course preferable to adjust (set) horizontally only those induction module heads 12 with which an improvement in the trend line Tr can be achieved. This is generally a maximum of half of all existing induction module heads 12, namely those whose closed end regions 13 are located at (above / below) a cold strip edge 22. It is of course possible to adjust the induction module heads 12 in pairs, e.g. by the same amount, since displacing an open central region 14 of an induction module head 12 has no significant effect on the temperature of the strip edge 22.

[0058] As shown in Fig. 10, a determination of a temperature distribution T z (Heat energy distribution T z) of the intermediate belt 2 in the transverse direction Qr in front of the induction furnace 1 , e.g. by a temperature scanner 40 (left in Fig. 4). The signal of this temperature scanner 40 is used to determine a required electrical power of the induction modules 10 or the induction module heads 12 of the induction furnace 1, a required electrical power distribution within the induction furnace 1 to the induction modules 10 or their induction module heads 12, as well as the required positions of the induction module heads 12 in the transverse direction Qr above / below the intermediate belt 2 by means of a suitable model, so that a desired temperature and a symmetrical temperature distribution T z is feasible within permissible limits.

[0059] In addition to a necessary (if possible symmetrical and if necessary uniform) energy input into the intermediate strip 2, e.g. for a finish rolling of the intermediate strip 2, this can already be used to compensate for an asymmetric temperature distribution of the intermediate strip 2 after rolling and before heating of the intermediate strip 2 in the induction furnace 1 by the induction furnace 1. This means that the relevant induction module heads 12 can initially be intentionally adjusted in such a way that a detected asymmetry of the incoming temperature distribution T z of the intermediate strip 2 can be compensated. - The positioning of the induction module heads 12 can then, of course, be further modified by a method according to the invention in such a way that a detected asymmetry of the outgoing temperature distribution T z of the intermediate band 2 can be compensated additionally or mainly.

[0060] A determination of the temperature distribution Tz of the intermediate strip 2 in the transverse direction Qr at an exit or a rear end of the induction furnace 1 can also usually be carried out by a temperature scanner 40 (right in Fig. 10). If, during this measurement, as described above, an asymmetry of the temperature distribution T z detected or measured, and e.g. a non-hori zontal trend line Tr is calculated, then a correction can be carried out. The correction concerns in particular a compensation of an asymmetric temperature distribution of the intermediate band 2 due to a deviation of the intermediate band center line M z from an induction furnace center line Mj for a temporally subsequent longitudinal section of the intermediate strip 2 in the induction furnace 1 .

[0061] This is done, for example, as indicated in Fig. 10, by moving those induction module heads 12 positioned on a colder strip edge 22 further in the direction of the colder strip edge 22 (dashed arrows). This causes, as shown in Figs. 8 and 9, an increased concentration of magnetic fields / eddy currents in the intermediate strip 2 on this side as well, and thus causes a higher strip edge temperature (see dashed line in the temperature distribution T z of Fig . 10 ) .

[0062] This can be done by a control / regulation, whereby the induction module heads 12 are moved until the determined temperature distribution T zis symmetrical again, e.g. the trend line Tr becomes horizontal. Preferably, a calculation model for compensating the temperature asymmetry can calculate a required displacement of these induction module heads 12 in advance and the induction module heads 12 can be positioned according to these calculated offsets, which leads to a faster achievement of a symmetrical temperature distribution T z in the intermediate volume 2 .

[0063] Taking into account an incoming temperature distribution T z The calculation model can calculate the setting of all induction module heads 12, i.e., the one marked with the dashed arrows in Fig. 10 as well as their complementary induction module heads 12 (in the pairs of induction modules 10). Thus, essentially all requirements regarding power consumption, symmetrization and, if necessary, equalization of the temperature distribution T zand compensation of temperature asymmetries are calculated essentially at any time in the process and are repeatedly specified as new setpoints for the control / regulation of the induction furnace 1.

[0064] Furthermore, the temperature distribution T z and from this, the trend line Tr can also be determined at another position (middle temperature scanner 40 in Fig. 10). This allows subsequent induction module heads 12 behind the middle temperature scanner 40 to control / regulate a symmetrical temperature distribution T zThe method can operate with the incoming temperature scanner 40 as the only temperature scanner 40, or with the outgoing temperature scanner 40 as the only temperature scanner 40. Of course, both temperature scanners 40, 40 can also be used. The middle temperature scanner 40 (in parentheses in Fig. 10) can be used in all embodiments, but can also be omitted.

Claims

Patent claims 1. Method for heating, in particular reheating, an intermediate strip (2) during the production of a flat strip, wherein the intermediate strip (2) is heated by induction module heads (12) of induction modules (10) of an induction furnace (1), in particular a rolling mill, preferably a steel strip production plant, characterized in that the induction module heads (12) are mechanically adjusted according to at least one current parameter of the intermediate strip (2) on / in the induction furnace (1) in such a way that at least one position in / on the induction furnace (1) , in the transverse direction (Qr) on / in the intermediate band (2) with respect to the intermediate band center line (M z ) a heat energy distribution that symmetrically develops over time (T z ) of the running intermediate belt (2).

2. Method according to one of the preceding claims, characterized in that according to the at least one parameter of the intermediate strip (2), in the chronological sequence at the at least one position in / on the induction furnace (1), by setting up induction module heads (12) it is intentionally attempted: • this heat energy distribution (T z ) of the intermediate band (2) in their preliminary symmetry or to further symmetrize this preliminary symmetry, • this heat energy distribution (T z ) of the intermediate belt (2) in the transverse direction (Qr) on / in the intermediate belt (2), and / or • a heat energy of a band edge (22) of the intermediate band (2) to a heat energy of the intermediate band center line (M z ) to be adjusted.

3. Method according to one of the preceding claims, characterized in that the parameter of the intermediate band (2) reflects an essentially current statement about the current intermediate strip (2) at / in the induction furnace (1) and / or at / in the rolling mill, and / or does not represent a merely general statement about the induction furnace (1) itself and / or the rolling mill itself.

4. Method according to one of the preceding claims, characterized in that the parameter of the intermediate band (2): • no exclusively geometric statement about the induction furnace (1) itself and / or the rolling mill itself, • no center line (M z ) or no transverse limitation of the intermediate strip (2) in the induction furnace (1) itself and / or in the rolling mill itself, • a geometric position of the intermediate strip (2) within the rolling mill and / or the induction furnace (1), and / or • a heat energy distribution (T z) of the intermediate strip (2) in the transverse direction (Qr) of the intermediate strip (2) on / in the rolling mill and / or on / in the induction furnace (1).

5. Method according to one of the preceding claims, characterized in that the parameter of the intermediate band (2) is the intermediate band center line (M z ) in the induction furnace (1), where: • another value, in particular another current measured value, is included in the parameter of the intermediate band (2), • in the parameters of the intermediate band (2) a current heat energy distribution (T z ) of the intermediate band (2), • the parameter of the intermediate band (2) essentially exclusively the intermediate band center line (M z ) represents, and / or • the interligament center line (M z ) is captured by a centerline detection.

6. Method according to one of the preceding claims, characterized in that: • the interligament center line (M z ) in the induction furnace (1) is determined from a current setting of exactly / at least one, exactly / at least two or exactly / at least four side guide rollers (30) on the intermediate belt (2), • a current setting of a lateral guide roller (30) is taken / received from a force control of the lateral guide roller (30), and / or • from a current setting of side guide rollers (30) a parallel and / or an angled current offset of the intermediate belt center line (M z ) opposite the induction furnace center line (M z ) is determined.

7. Method according to one of the preceding claims, characterized in that the parameter of the intermediate strip (2) is a heat energy distribution (T z ) of the intermediate strip (2) at / in the induction furnace (1), where: • another value, in particular another current measured value, is included in the parameter of the intermediate band (2), • in the parameter of the intermediate band (2) a current intermediate band center line (M z ) is received, • the parameter of the intermediate band (2) essentially exclusively the heat energy distribution (T z ) of the intermediate band (2), and / or • the heat energy distribution (T z ) of the intermediate strip (2) is detected by a temperature detection device, in particular a temperature scanner (40).

8. Method according to one of the preceding claims, characterized in that the current heat energy distribution (T z ) of the intermediate strip (2) in the transverse direction (Qr) is determined, and from the heat energy distribution (T z ) a current Trend line (Tr) is determined, which represents a current degree of symmetry of the heat energy distribution (T z ) of the intermediate band (2) in the transverse direction (Qr), whereby on the basis of this current trend line (Tr), induction module heads (12) of the induction furnace (1) are adjusted in such a way that the current degree of symmetry of the heat energy distribution (T z ) of the intermediate band (2) in the transverse direction (Qr) is symmetrical or at least not asymmetrical.

9. Method according to one of the preceding claims, characterized in that an incoming, current heat energy distribution (T z ) of the intermediate belt (2) in the transverse direction (Qr) is determined in front of the actual and / or in the front induction furnace (1), from which heat energy distribution (T z) a required electrical power of the induction furnace (1), a required electrical power distribution within the induction furnace (1) and / or a required position of induction module heads (12) in the transverse direction (Qr) is determined, wherein the induction module heads (12) are preferably initially intended to be positioned in such a way that an asymmetry of a temperature distribution (T z ) of the incoming intermediate belt (2) is compensated.

10. Method according to one of the preceding claims, characterized in that an outgoing, current heat energy distribution (T z ) of the intermediate belt (2) in the transverse direction (Qr) in the rear and / or behind the actual induction furnace (1), from which heat energy distribution (T z ) a current trend line (Tr) is determined, which represents a current degree of symmetry of the heat energy distribution (T z) of the intermediate band (2) in the transverse direction (Qr), and the induction module heads (12) are adjusted on the basis of the trend line (Tr) in such a way that an asymmetry of a Temperature distribution (T z ) of the outgoing intermediate strip (2) is compensated, wherein preferably an incoming, current heat energy distribution (T z ) of the intermediate belt (2) in the transverse direction (Qr) is taken into account.

11. Method according to one of the preceding claims, characterized in that the method is operated in such a way that a current trend line (Tr) of a current heat energy distribution (T z ) of the intermediate band (2) , approaches a desired trend line (Tr).

12. Plant control for an induction furnace, a rolling mill or a steel strip production plant, in particular for endless strip production, characterized in that a method according to one of the preceding claims can be carried out and / or is carried out by the plant control.

13. Induction furnace (1), rolling mill or steel strip production plant, in particular for endless strip production, characterized in that the induction furnace (1), the rolling mill or the steel strip production plant has induction module heads (12), wherein the induction furnace (1), the rolling mill or the steel strip production plant has a plant control according to the preceding claim, and / or a method according to one of the preceding claims can be carried out and / or is carried out by the induction furnace (1), the rolling mill or the steel strip production plant.

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