Operating procedures, control device and rolling mill

Abstract

The invention relates to an operating method for a rolling mill, preferably a hot rolling mill, comprising at least one rolling stand, preferably two, three, four, five, six, seven, eight, nine or more rolling stands, for forming a metallic rolled material, in particular a hot strip, by means of at least n = 2 forming process steps in which the metallic rolled material passes through a rolling stand, in particular by means of at least n = 3, n = 4, n = 5, n = 6 or more forming process steps, wherein a normalized relative thickness reduction of the (i-1)th forming process step or the (i-2)th forming process step or the (i-3)th forming process step is less than or equal to the normalized relative thickness reduction of the i-th forming process step.

Description

[0001] The invention relates to an operating method for a rolling mill, preferably a hot rolling mill, comprising at least one rolling stand, preferably two, three, four, five, six, seven, eight, nine or more rolling stands, for forming a metallic rolled product, in particular a hot strip, by means of at least n = 2 forming process steps in which the metallic rolled product passes through a rolling stand, in particular by means of at least n = 3, n = 4, n = 5, n = 6 or more forming process steps, wherein the rolled product comprises a semi-finished product and / or a pre-product and / or an intermediate product and / or a product made of ferrous, steel and / or a non-ferrous metal material.

[0002] Furthermore, the invention relates to a control device set up for carrying out such an operating procedure.

[0003] The invention further relates to a rolling mill comprising such a control unit.

[0004] In particular, operating procedures, control devices and rolling mills of the type are known from the prior art.

[0005] In rolling, especially in multi-stage rolling with a plurality of forming process steps, a large number of process boundary conditions must be taken into account for the operation of a rolling mill.

[0006] A priority here is the reliable and / or continuous thickness reduction of the metallic rolled material in a single forming process step. In particular, mis-rolling and / or overheating of work rolls should be avoided.

[0007] A first type of rolling error can be understood as a build-up of the metal being rolled in front of a rolling stand, thus interrupting a continuous rolling process. This first type of rolling error must be avoided at all costs, as it can pose immediate safety risks to personnel and materials. Such rolling errors are also referred to as cobbles or cobbles.

[0008] Overheating of work rolls can also lead to a loss of precision during rolling, resulting in a second type of defective rolling. This type of defective rolling leads to an increased reject rate of metallic rolled material. Furthermore, overheating of work rolls can also cause increased wear on the rolling mill, which can raise the costs of rolling metallic rolled material.

[0009] Overall, the objective of operating a rolling mill is to achieve or ensure safe and cost-efficient operation. In other words, increasing rolling stability and / or increasing the production rate of rolled metal products while simultaneously avoiding safety risks is a key task in the operation of rolling mills.

[0010] The invention is based on the objective of providing an improvement or an alternative to the prior art.

[0011] According to a first aspect, the object of the invention is to provide an operating method for a rolling mill, preferably a hot rolling mill, comprising at least one rolling stand, preferably two, three, four, five, six, seven, eight, nine or more rolling stands, for forming a metallic rolled product, in particular a hot strip, by means of at least n = 2 forming process steps in which the metallic rolled product passes through a rolling stand, in particular by means of at least n = 3, n = 4, n = 5, n = 6 or more forming process steps. - where an i-th forming process step from a set of i = 1 to n forming process steps leads to a relative decrease in thickness Δhi=hzu,i−hab,ihzu,i of the metallic rolled material under the influence of a rolling stand or the metallic rolled material passes through a rolling stand without any relative decrease in thickness, wherein the metallic rolled material has a thickness h zu,iruns towards a rolling mill and with a thickness h ab,i expires; - wherein an (i-1)-th forming process step is arranged temporally before the i-th forming process step; - wherein the operating process comprises a k-th forming process step from a set of k = 1 to n forming process steps, wherein the k-th forming process step is characterized by the fact that the k-th forming process step has the greatest relative thickness reduction Δhk=hzu,k−hab,khzu,k from the set of k = 1 to n of the forming process steps; - where a normalized relative thickness reduction of the i-th forming process step ‖Δhi‖=ΔhiΔhk from the quotient of the relative thickness reduction of the i-th forming process step Δh i and the relative thickness reduction of the k-th forming process step Δh k results in, where the normalized relative thickness reduction of the i-th forming process step ||Δhi || = 0 if no thickness reduction of the metallic rolled stock occurs in the i-th forming process step; where the operating procedure - for a relative decrease in thickness Δh i-1 > 0 of the (i - 1)th forming process step with Δhi−1=hzu,i−1−hab,i−1hzu,i−1 a normalized relative decrease in thickness ‖Δhi−1‖=Δhi−1Δhk of the (i-1)-th forming process step, which is less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is; or - for a relative decrease in thickness Δh i-2 > 0 of the (i -2)-th forming process step with Δhi−2=hzu,i−2−hab,i−2hzu,i−2 with a relative decrease in thickness Δh i-1 =0 of the (i - 1)th forming process step a normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk of the (i-2)-th forming process step, which is less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is; or - for a relative decrease in thickness Δh i-3 > 0 of the (i-3)th forming process step with Δhi−3=hzu,i−3−hab,i−3hzu,i−3 with a relative decrease in thickness Δh i-1 =0 of the (i - 1)th forming process step and with a relative thickness reduction Δh i-2 = 0 of the (i -2)-th forming process step a normalized relative thickness reduction ‖Δhi−3‖=Δhi−3Δhk of the (i-3)-th forming process step, which is less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step.

[0012] When faced with the objective of increasing rolling stability and / or increasing the production rate of metallic rolled material while simultaneously avoiding safety risks, flexural buckling of the metallic rolled material can come into focus.

[0013] When a metallic workpiece is rolled, it loses absolute thickness in almost every forming process step. Along with the absolute thickness of the metallic workpiece, its area moment of inertia in the thickness direction also decreases.

[0014] Reducing the thickness of rolled metal requires a rolling force exerted on the metal by the work rolls of a rolling mill. This, in turn, is accompanied by a force acting on the incoming metal by the work rolls against the conveying direction of the metal, which can also be described as an impact force.

[0015] When considering the bending and buckling of the metallic rolled material approaching the rolling stand, this impact force can be equated with a buckling load acting on the approaching metallic rolled material.

[0016] In an operating procedure for a rolling mill with a plurality of forming process steps, each with the same absolute thickness reduction of the metallic rolled material and thus approximately the same buckling load on the metallic rolled material, the theoretical buckling safety is reduced from forming process step to forming process step as a result of the decreasing area moment of inertia in the thickness extension direction, at least if the free buckling lengths in front of each rolling stand are considered to be the same to a first approximation.

[0017] In other words, the tapping conditions are changed from one forming process step to the next, in particular the insertion conditions and / or the pull-through conditions for the metallic rolled material.

[0018] For the reasons stated above, it is part of current rolling practice that the standardized relative thickness reduction decreases from one forming process step to the next, so that the necessary buckling resistance of the respective incoming metallic rolled material can be ensured for smooth and safe operation, so that cobbles can be avoided and rolling stability can be guaranteed.

[0019] Contrary to the preceding doctrine, an operating method for a rolling mill is proposed here, which includes at least one forming process step that, compared to the preceding forming process step with a normalized relative thickness reduction greater than zero, does not exhibit a reduction in the normalized relative thickness reduction. For this comparison, those forming process steps in which the metallic rolled material is merely rolled in a rolling stand without inducing a normalized relative thickness reduction in these forming process steps are to be disregarded. Accordingly, the comparison between two adjacent forming process steps, each exhibiting a normalized relative thickness reduction, is to be carried out, thus justifying the case distinction in the corresponding characteristic.

[0020] In other words, an operating procedure for a rolling mill is proposed in which - according to a first variant for a relative decrease in thickness Δh i-1 > 0 a normalized relative thickness decrease ‖Δhi−1‖=Δhi−1Δhk of the (i-1)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is; or - according to a second variant for a relative decrease in thickness Δh i-1 = 0 and for a relative decrease in thickness Δh i-2 > 0 a normalized relative thickness decrease ‖Δhi−2‖=Δhi−2Δhk of the (i-2)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is; or - according to a third variant for a relative decrease in thickness Δh i-1 = 0, for a relative decrease in thickness Δh i-2 = 0 and for a relative decrease in thickness Δh i-3 > 0 a normalized relative thickness decrease ‖Δhi−3‖=Δhi−2Δhk of the (i - 3)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is; or - according to a fourth variant for a relative decrease in thickness Δh i-1 = 0, for a relative decrease in thickness Δh i-2 = 0 , for a relative decrease in thickness Δh i-3 = 0 and for a relative decrease in thickness Δh i-4 > 0 a normalized relative thickness decrease ‖Δhi−4‖=Δhi−4Δhk of the (i - 4)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is; or - according to a fifth variant for a relative thickness decrease Δh i-1 = 0, for a relative decrease in thickness Δh i-2 = 0, for a relative decrease in thickness Δh i-3 = 0, for a relative decrease in thickness Δh i-4= 0 and for a relative decrease in thickness Δh i-5 > 0 a normalized relative thickness decrease ‖Δhi−5‖=Δhi−5Δhk of the (i - 5)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step.

[0021] Specifically, it is proposed here that the normalized relative thickness reduction during a series of forming process steps, ignoring intermediate forming process steps in which no normalized relative thickness reduction is achieved, should increase at least once or at least not decrease, since, in light of the above, it was unexpectedly found that this can improve the rolling stability, thus increasing the safety of the operating process and / or increasing the productivity of the operating process by increasing the output capacity of the rolling mill.

[0022] As explained below, it is currently assumed that this observed effect is related to microscopic changes in the metallic rolled material.

[0023] In rolling, a metallic material is passed between multiple rollers and plastically deformed under pressure, thus assuming a new shape. The deformation of the rolled metallic material is usually visible to the naked eye and can therefore be described as a macroscopic process of change.

[0024] During and after the rolling of a metallic rolled material, microscopic changes can occur in addition to macroscopic changes, in particular a change in the structural characteristics of the metallic rolled material, especially a change in phase fractions and / or grain sizes.

[0025] Changes in the microstructural properties of rolled metals can also be understood as changes in the microscopic properties of the rolled metals. Increasingly complex, changes in microstructural properties are a dynamic process, meaning that a transition between two states does not occur abruptly, but rather over time.

[0026] If a change in these microscopic properties occurs, it is usually accompanied by a change in macroscopic properties of the metallic rolled material, in particular changes in toughness and / or brittleness, so that changes in the mechanical properties of the metallic rolled material can be observed, in particular changes in hardness and / or toughness and / or stiffness and / or strength and / or ductility of the metallic rolled material.

[0027] A change in the microstructure of rolled metal therefore generally leads to a change in the yield strength and / or the proof stress and / or the modulus of elasticity and / or the tensile strength and / or the area of ​​reduction at fracture and / or the Lüders elongation and / or the uniform elongation and / or the impact strength. Furthermore, a change in microstructure can also affect other properties of the rolled metal, in particular its weldability.

[0028] Accordingly, it is plausible that the observed increase in rolling stability is related to a microscopic change in the metallic rolled material influenced by the proposed operating procedure.

[0029] To support the observations made here, the following research was conducted: The mechanical properties of a metallic rolled product, especially a hot-rolled strip, can be influenced by the grain size. A fine grain structure can have a positive effect on the strength and toughness properties and can be the result of the recrystallization and recovery processes occurring in the material during forming and subsequent transformation.The recrystallization and recovery processes occurring in the material during forming can therefore be important for the rolling stability, which is promoted by the deliberate and controlled determination and process management proposed here, and the resulting grain refinement can produce a microstructure with improved mechanical properties, in particular with more homogeneous mechanical properties over a length and / or a width and / or a thickness of the metallic rolled material and / or even with defined mechanical properties.

[0030] Preferably, the normalized relative thickness decrease is used. ‖Δhi−1‖=Δhi−1Δhk of the (i-1)th forming process step or the normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk of the (i-2)th forming process step or the normalized relative thickness reduction ‖Δhi−3‖=Δhi−3Δhk of the (i-3)th forming process step or the normalized relative thickness reduction ‖Δhi−4‖=Δhi−2Δhk of the (i-4)th forming process step or the normalized relative thickness reduction ‖Δhi−5‖=Δhi−2Δhk of the (i-5)-th forming process step by greater than or equal to 2.5% less than the normalized relative thickness reduction ||Δh i || of the i-th forming process step, further preferably by more than or equal to 5.0% smaller, more preferably by more than or equal to 10.0% smaller, and particularly preferably by more than or equal to 15.0% smaller. The normalized relative thickness reduction is advantageous. ‖Δhi−1‖=Δhi−1Δhk of the (i-1)th forming process step or the normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk of the (i-2)th forming process step or the normalized relative thickness reduction ‖Δhi−3‖=Δhi−2Δhk of the (i-3)th forming process step or the normalized relative thickness reduction ‖Δhi−4‖=Δhi−2Δhk of the (i-4)th forming process step or the normalized relative thickness reduction ‖Δhi−5‖=Δhi−2Δhk of the (i- 5)-th forming process step by more than or equal to 20.0 % less than the normalized relative thickness reduction ||Δh i || of the i-th forming process step, further advantageously by more than or equal to 30.0 % smaller, preferably by more than or equal to 40.0 % smaller and particularly preferably by more than or equal to 60.0 % smaller.

[0031] Preferably, the normalized relative thickness decrease is used. ‖Δhi−1‖=Δhi−1Δhk of the (i-1)th forming process step or the normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk of the (i-2)th forming process step or the normalized relative thickness reduction ‖Δhi−3‖=Δhi−2Δhk of the (i-3)th forming process step or the normalized relative thickness reduction ‖Δhi−4‖=Δhi−2Δhk of the (i-4)th forming process step or the normalized relative thickness reduction ‖Δhi−5‖=Δhi−2Δhk of the (i-5)th forming process step by less than or equal to 97.5% less than the normalized relative thickness reduction ||Δh i || of the i-th forming process step, further preferably by less than or equal to 95.0% smaller, more preferably by less than or equal to 90.0% smaller, and most preferably by less than or equal to 85.0% smaller. The normalized relative thickness reduction is advantageous. ‖Δhi−1‖=Δhi−1Δhk of the (i-1)th forming process step or the normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk of the (i-2)th forming process step or the normalized relative thickness reduction ‖Δhi−3‖=Δhi−2Δhk of the (i-3)th forming process step or the normalized relative thickness reduction ‖Δhi−4‖=Δhi−2Δhk of the (i-4)th forming process step or the normalized relative thickness reduction ‖Δhi−5‖=Δhi−2Δhk of the (i - 5)th forming process step by less than or equal to 80.0 % less than the normalized relative thickness reduction ||Δh i || of the i-th forming process step, further advantageously by less than or equal to 70.0 % smaller, preferably by less than or equal to 60.0 % smaller and particularly preferably by less than or equal to 40.0 % smaller.

[0032] In the operating procedure proposed here for a rolling mill, the quotient of the normalized relative thickness reduction of two consecutively arranged forming process steps with an occurring normalized relative thickness change, in particular ‖Δhi−1‖‖Δhi‖ or ‖Δhi−2‖‖Δhi‖ or ‖Δhi−3‖‖Δhi‖ or ‖Δhi−4‖‖Δhi‖ or ‖Δhi−5‖‖Δhi‖ less than or equal to 1, since a normalized relative thickness decrease ||Δh i-1 || of the (i - 1)th forming process step ||Δh i-2 || of the (i- 2)-th forming process step or ||Δh i-3 || of the (i - 3)th forming process step or ||Δh i-4 || of the (i-4)th forming process step or ||Δh i-5 || of the (i -5)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is proposed. As explained above, this differs from a component of conventional rolling practice, in which, for reasons of rolling stability, in particular buckling resistance, ‖Δhi−1‖‖Δhi‖ or ‖Δhi−2‖‖Δhi‖ or ‖Δhi−3‖‖Δhi‖ or ‖Δhi−4‖‖Δhi‖ or ‖Δhi−5‖‖Δhi‖ was chosen to be greater than or equal to 1.

[0033] Tests unexpectedly showed that the actual rolling stability can be increased if ‖Δhi−1‖‖Δhi‖ or ‖Δhi−2‖‖Δhi‖ or ‖Δhi−3‖‖Δhi‖ or ‖Δhi−4‖‖Δhi‖ or ‖Δhi−5‖‖Δhi‖ less than or equal to 1 is chosen.

[0034] More detailed investigations into the observable higher rolling stability unexpectedly revealed that the proposed operating method achieves a comparatively higher yield strength of the metallic rolled material with regard to its macroscopic properties, particularly its material and microstructure characteristics. Similarly, a comparatively higher tensile strength was also unexpectedly found, thus explaining the observed improved rolling stability.

[0035] Furthermore, a comparatively higher toughness of the metallic rolled material could also be achieved with the operating method proposed here for the metallic rolled material.

[0036] Initial laboratory tests have shown that the proposed operating method also improves the microscopic properties of the rolled metallic material compared to the state of the art. ‖Δhi−1‖‖Δhi‖ The process has shown unexpected improvements greater than 1, in particular smaller austenite grain sizes and / or smaller ferrite grain sizes could be achieved. The homogeneity of the microstructural properties can also be unexpectedly improved with the operating method proposed here.

[0037] Initial results regarding the aforementioned properties can be found in Table 1. It is understood that the notation of the variable quantity, in light of the quotient of adjacent forming process steps considered here, each with a normalized relative thickness reduction greater than zero, also applies analogously to the other variants of the invention described here; in particular, ‖Δhi−1‖‖Δhi‖ Therefore, in Table 1, the other variants are also explicitly included for ‖Δhi−2‖‖Δhi‖ and / or ‖Δhi−3‖‖Δhi‖ and / or ‖Δhi−4‖‖Δhi‖ and / or ‖Δhi−5‖‖Δhi‖

[0038] Table 1: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product; yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; StdT. corresponds to the current part of rolling practice.

[0039] In the context of this description, the term "rolling stand" can be understood to mean any rolling stand that can be used to reduce the thickness of a metallic rolled product. In particular, this can include a rolling stand of a heavy plate mill and / or a rolling stand of a hot rolling mill and / or a cold rolling mill. Furthermore, the term "rolling stand" preferably encompasses both a rolling stand configured for reversing operation and a rolling stand for operation with a preferred rolling direction. Both a rolling stand of a roughing mill and a rolling stand of a finishing mill, as well as a hot rolling stand and a cold rolling stand, can preferably be understood as a rolling stand.

[0040] In this context, a "forming process step" can be understood as the passage through a roll gap formed by two work rolls of a rolling stand, preferably regardless of whether a thickness reduction of the metallic rolled stock occurs during this passage. Therefore, a reduction in the thickness of the metallic rolled stock preferably does not need to be demonstrable during a forming process step. Rather, a rolling stand can also be passed through openly during a forming process step, so that the roll gap of the passed rolling stand can be greater than or equal to the thickness of the incoming metallic rolled stock.

[0041] It is understood that forming process steps with different run variables can be numbered starting with the 1st forming process step and ending with the nth forming process step, in particular with the run variables i, j, k and / or l, analogous to the i-th forming process step, the j-th forming process step, the k-th forming process step and / or the l-th forming process step. An (i-1)-th forming process step is arranged before the i-th forming process step in a series of 1 to n forming process steps, in particular immediately before the i-th forming process step, and an (i+1)-th forming process step is arranged after the i-th forming process step in a series of 1 to n forming process steps, in particular immediately after the i-th forming process step.Preferably, the running variables j, k and / or 1 are understood as an index, i.e., precisely as the j-th forming process step, the k-th forming process step and / or the l-th forming process step.

[0042] Within a rolling mill, particularly adjacent to the at least one rolling stand or preferably between two rolling stands, various additional units for processing the metallic rolled material can be arranged. In particular, further processing steps can also be arranged between two forming process steps included in the operating method discussed here, without thereby departing from the aspect of the invention proposed here. Thus, in addition to the at least one rolling stand, a transfer bar cooling system and / or an induction heating system and / or a tunnel furnace and / or a swaging device and / or the like can preferably be arranged within the rolling mill for processing the metallic rolled material. However, none of these units constitute a forming process step, since none of these units is designed to bring about a relative reduction in the thickness of the metallic rolled material in the sense of the invention.

[0043] Under a “normalized relative thickness reduction” ||Δh i || a normalized “relative thickness reduction” Δh i understood, where the relative thickness reduction is defined as the difference in the absolute thickness of the metallic rolled stock before the individually considered forming process step, in particular for the i-th forming process step, denoted by h. zu,i , and after the forming process step, in particular for the i-th forming process step, denoted by h ab,i , relative to the absolute thickness before the forming process step. Accordingly, the relative thickness reduction of the i-th forming process step Δh can be determined. i with Δhi=hzu,i−hab,ihzu,i This can be calculated, and analogous calculations can be performed for differing forming process steps and other running variables and / or indices. In particular, the relative thickness reduction of the k-th forming process step Δh can be calculated. k with Δhk=hzu,k−hab,khzu,k calculated.

[0044] The normalization of the relative thickness reduction is achieved by selecting the relative thickness reduction that, in the series of forming process steps considered here, corresponds to the forming process step exhibiting the greatest relative thickness reduction. By definition, this step is designated with the index of the k-th forming process step. Accordingly, the normalized relative thickness reduction of the i-th forming process step can be expressed as ||Δh i || ‖Δhi‖=ΔhiΔhk can be calculated, whereby this can be calculated analogously for different forming process steps.

[0045] It should be explicitly noted here that the metallic rolled stock does not necessarily experience a relative decrease in thickness during the i-th forming process step. The running variable i is incremented to the next integer even if the metallic rolled stock only passes through one rolling stand, particularly an open rolling stand, without experiencing a decrease in thickness. Therefore, in the case of a rolling mill where at least one rolling stand is traversed by a metallic rolled stock in a reversing motion, the running variable i can be incremented multiple times, even if the metallic rolled stock only experiences a decrease in thickness during a subset of forming process steps or during no forming process step at all.

[0046] If the metallic rolled stock experiences no thickness reduction in the i-th forming process step, then the normalized relative thickness reduction is, by definition, to be equated to 0, i.e., ||Δh i || = 0.

[0047] It should be noted here that, within the context of the present patent application, indefinite articles and indefinite numerical indications such as "one...", "two...", etc., are generally to be understood as minimum indications, i.e., as "at least one...", "at least two...", etc., unless it is clear from the context or the specific text of a particular passage that only "exactly one...", "exactly two...", etc., is meant.

[0048] It should be noted here that, within the context of the present patent application, the term "in particular" is always to be understood as introducing an optional, preferred feature. The term is not to be understood as "namely" or "namely".

[0049] The operating procedure can optionally be further developed advantageously if the operating procedure has n = 3 forming process steps greater than or equal to n, wherein an (i+1)-th forming process step is arranged after the i-th forming process step, wherein - a normalized relative decrease in thickness ‖Δhi+1‖=Δhi+1Δhk with Δhi+1=hzu,i+1−hab,i+1hzu,i+1 of the (i + 1)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i || of the i-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi‖‖Δhi+1‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+1‖ greater than or equal to 1.0, preferably greater than or equal to 2.0, and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+1‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.01.

[0050] It was unexpectedly discovered that the rolling stability can be further increased if the normalized relative thickness reduction of the (i+1)-th forming process step is less than or equal to the normalized relative thickness reduction of the i-th forming process step. Preferably, a ratio of the normalized relative thickness reductions ‖Δhi‖‖Δhi+1‖ and / or ‖Δhi−1‖‖Δhi+1‖ greater than or equal to 1.01, more preferably greater than or equal to 1.5, more preferably greater than or equal to 2.0, more preferably greater than or equal to 3.2, and particularly preferably greater than or equal to 4.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi‖‖Δhi+1‖ and / or ‖Δhi−1‖‖Δhi+1‖ greater than or equal to 6.0, further preferably greater than or equal to 7.5, more preferably greater than or equal to 10, further preferably greater than or equal to 15 and particularly preferably greater than or equal to 20 or greater than or equal to 31 or greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0051] The fixed costs of a rolling mill can be reduced in conjunction with a reduction in the necessary forming process steps between an initial thickness of the metallic rolled material before entering the rolling mill and a final thickness of the metallic rolled material when exiting the rolling mill, if a ratio of the standardized relative thickness reductions ‖Δhi−1‖‖Δhi+1‖ less than or equal to 1.0, more preferably less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, and most preferably less than or equal to 0.32. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+1‖ less than or equal to 0.2, further preferably less than or equal to 0.15, more preferably less than or equal to 0.1, further preferably less than or equal to 0.075 and particularly preferably less than or equal to 0.06 or less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.015 or less than or equal to 0.01.

[0052] The operating process can preferably be further developed advantageously if the operating process has n = 4 forming process steps greater than or equal to n, wherein an (i+2)th forming process step is arranged after the (i + 1)th forming process step, wherein - a normalized relative thickness reduction thickness reduction ‖Δhi+2‖=Δhi+2Δhk with Δhi+2=hzu,i+2−hab,i+2hzu,i+2 of the (i + 2)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i+1|| of the (i+1)-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi+2‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+2‖ greater than or equal to 1.0, preferably greater than or equal to 2.0, and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+2‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.01.

[0053] It was unexpectedly discovered that the rolling stability can be further increased if the normalized relative thickness reduction of the (i+2)th forming process step is less than or equal to the normalized relative thickness reduction of the (i+1)th forming process step. Preferably, a ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi+2‖ and / or ‖Δhi−1‖‖Δhi+2‖ greater than or equal to 1.01, more preferably greater than or equal to 1.5, more preferably greater than or equal to 2.0, more preferably greater than or equal to 3.2, and particularly preferably greater than or equal to 4.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi+2‖ and / or ‖Δhi−1‖‖Δhi+2‖ greater than or equal to 6.0, further preferably greater than or equal to 7.5, more preferably greater than or equal to 10, further preferably greater than or equal to 15 and particularly preferably greater than or equal to 20 or greater than or equal to 31 or greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0054] The fixed costs of a rolling mill can be reduced in conjunction with a reduction in the necessary forming process steps between an initial thickness of the metallic rolled material before entering the rolling mill and a final thickness of the metallic rolled material when exiting the rolling mill, if a ratio of the standardized relative thickness reductions ‖Δhi−1‖‖Δhi+2‖ less than or equal to 1.0, more preferably less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, and most preferably less than or equal to 0.32. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+2‖ less than or equal to 0.2, further preferably less than or equal to 0.15, more preferably less than or equal to 0.1, further preferably less than or equal to 0.075 and particularly preferably less than or equal to 0.06 or less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.015 or less than or equal to 0.01.

[0055] The rolling stability can preferably be further improved if the operating process has n = 5 forming process steps greater than or equal to n, wherein an (i+3)th forming process step is arranged after the (i+2)th forming process step, wherein - a normalized relative decrease in thickness ‖Δhi+3‖=Δhi+3Δhk with Δhi+3=hzu,i+3−hab,i+3hzu,i+3 of the (i+ 3)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i+2 || of the (i +2)-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+3‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+3‖ greater than or equal to 1.0, preferably greater than or equal to 2.0, and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+3‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.01.

[0056] It was unexpectedly discovered that the rolling stability can be further increased if the normalized relative thickness reduction of the (i+3)-th forming process step is less than or equal to the normalized relative thickness reduction of the (i+2)-th forming process step. Preferably, a ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+3‖ and / or ‖Δhi−1‖‖Δhi+3‖ greater than or equal to 1.01, more preferably greater than or equal to 1.5, more preferably greater than or equal to 2.0, more preferably greater than or equal to 3.2, and particularly preferably greater than or equal to 4.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+3‖ and / or ‖Δhi−1‖‖Δhi+3‖ greater than or equal to 6.0, further preferably greater than or equal to 7.5, more preferably greater than or equal to 10, further preferably greater than or equal to 15 and particularly preferably greater than or equal to 20 or greater than or equal to 31 or greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0057] The fixed costs of a rolling mill can be reduced in conjunction with a reduction in the necessary forming process steps between an initial thickness of the metallic rolled material before entering the rolling mill and a final thickness of the metallic rolled material when exiting the rolling mill, if a ratio of the standardized relative thickness reductions ‖Δhi−1‖‖Δhi+3‖ less than or equal to 1.0, more preferably less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, and most preferably less than or equal to 0.32. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+3‖ less than or equal to 0.2, further preferably less than or equal to 0.15, more preferably less than or equal to 0.1, further preferably less than or equal to 0.075 and particularly preferably less than or equal to 0.06 or less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.015 or less than or equal to 0.01.

[0058] An optional further development of the operating process with a further improved rolling stability can be achieved if the operating process has n = 6 forming process steps greater than or equal to n = 6, wherein an (i+4)th forming process step is arranged after the (i+3)th forming process step, wherein - a normalized relative decrease in thickness ‖Δhi+4‖=Δhi+4Δhk with Δhi+4=hzu,i+4−hab,i+4hzu,i+4 of the (i + 4)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i+3 || of the (i+3)-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+4‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+4‖ greater than or equal to 1.0, preferably greater than or equal to 2.0, and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+4‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.01.

[0059] It was unexpectedly discovered that the rolling stability can be further increased if the normalized relative thickness reduction of the (i+4)th forming process step is less than or equal to the normalized relative thickness reduction of the (i+3)th forming process step. Preferably, a ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+4‖ and / or ‖Δhi−1‖‖Δhi+4‖ greater than or equal to 1.01, more preferably greater than or equal to 1.5, more preferably greater than or equal to 2.0, more preferably greater than or equal to 3.2, and particularly preferably greater than or equal to 4.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+4‖ and / or ‖Δhi−1‖‖Δhi+4‖ greater than or equal to 6.0, further preferably greater than or equal to 7.5, more preferably greater than or equal to 10, further preferably greater than or equal to 15 and particularly preferably greater than or equal to 20 or greater than or equal to 31 or greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0060] The fixed costs of a rolling mill can be reduced in conjunction with a reduction in the necessary forming process steps between an initial thickness of the metallic rolled material before entering the rolling mill and a final thickness of the metallic rolled material when exiting the rolling mill, if a ratio of the standardized relative thickness reductions ‖Δhi−1‖‖Δhi+4‖ less than or equal to 1.0, more preferably less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, and most preferably less than or equal to 0.32. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+4‖ less than or equal to 0.2, further preferably less than or equal to 0.15, more preferably less than or equal to 0.1, further preferably less than or equal to 0.075 and particularly preferably less than or equal to 0.06 or less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.015 or less than or equal to 0.01.

[0061] The operating procedure can be further developed according to a preferred embodiment, wherein - the operating procedure includes an (i-2)-th forming process step with a normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk with Δhi−2=hzu,i−2−hab,i−2hzu,i−2 exhibits; and - preferably a ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - preferably a ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ less than or equal to 1.0, preferably less than or equal to 0.2 and particularly preferably greater than or equal to 0.01.

[0062] The operating procedure proposed here allows for a greater degree of deformation of the metallic rolled material through the additional forming process step.

[0063] Unexpectedly, it was discovered that rolling stability can be further improved by using a ratio of the normalized relative thickness reductions. ‖Δhi−2‖‖Δhi−1‖ greater than or equal to 1.5, preferably greater than or equal to 3.2, more preferably greater than or equal to 4.5, and particularly preferably greater than or equal to 7.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ greater than or equal to 10, further preferably greater than or equal to 15, more preferably greater than or equal to 20, further preferably greater than or equal to 31 and particularly preferably greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0064] A further unexpected improvement in rolling stability can be achieved by using a ratio of the normalized relative thickness reductions. ‖Δhi−2‖‖Δhi−1‖ less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, more preferably less than or equal to 0.32, and most preferably less than or equal to 0.15. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ less than or equal to 0.15, further preferably less than or equal to 0.1, preferably less than or equal to 0.075, further preferably less than or equal to 0.06 and particularly preferably less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.02.

[0065] The operating procedure can optionally be further developed, whereby - the operating procedure includes an (i-3)-th forming process step with a normalized relative thickness reduction ‖Δhi−3‖=Δhi−3Δhk with Δhi−3=hzu,i−3−hab,i−3hzu,i−3 exhibits; and - preferably a ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - preferably a ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ less than or equal to 1.0, preferably less than or equal to 0.2 and particularly preferably greater than or equal to 0.01.

[0066] This allows for a greater degree of deformation of the metallic rolled material, attributable to the additional forming process step.

[0067] Unexpectedly, it was discovered that rolling stability can be further improved by using a ratio of the normalized relative thickness reductions. ‖Δhi−3‖‖Δhi−2‖ greater than or equal to 1.5, preferably greater than or equal to 3.2, more preferably greater than or equal to 4.5, and particularly preferably greater than or equal to 7.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ greater than or equal to 10, further preferably greater than or equal to 15, more preferably greater than or equal to 20, further preferably greater than or equal to 31 and particularly preferably greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0068] A further unexpected improvement in rolling stability can be achieved by using a ratio of the normalized relative thickness reductions. ‖Δhi−3‖‖Δhi−2‖ less than or equal to 0.75, further preferably less than or equal to 0.6, more preferably less than or equal to 0.45, more preferably less than or equal to 0.32 and most preferably less than or equal to 0.15.

[0069] According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ less than or equal to 0.15, further preferably less than or equal to 0.1, preferably less than or equal to 0.075, further preferably less than or equal to 0.06 and particularly preferably less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.02.

[0070] The operating procedure can preferably be further developed, whereby - the operating procedure includes an (i-4)th forming process step with a normalized relative thickness reduction ‖Δhi−4‖=Δhi−4Δhk with Δhi−4=hzu,i−4−hab,i−4hzu,i−4 exhibits; and - preferably a ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - preferably a ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ less than or equal to 1.0, preferably less than or equal to 0.2 and particularly preferably greater than or equal to 0.01.

[0071] The additional forming process step can lead to a greater degree of deformation of the metallic rolled material.

[0072] Unexpectedly, it was discovered that rolling stability can be further improved by using a ratio of the normalized relative thickness reductions. ‖Δhi−4‖‖Δhi−3‖ greater than or equal to 1.5, preferably greater than or equal to 3.2, more preferably greater than or equal to 4.5, and particularly preferably greater than or equal to 7.5. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ greater than or equal to 10, further preferably greater than or equal to 15, more preferably greater than or equal to 20, further preferably greater than or equal to 31 and particularly preferably greater than or equal to 45 or greater than or equal to 60 or greater than or equal to 75 or less than or equal to 100.

[0073] A further unexpected improvement in rolling stability can be achieved by using a ratio of the normalized relative thickness reductions. ‖Δhi−4‖‖Δhi−3‖ less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, more preferably less than or equal to 0.32, and most preferably less than or equal to 0.15. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ less than or equal to 0.15, further preferably less than or equal to 0.1, preferably less than or equal to 0.075, further preferably less than or equal to 0.06 and particularly preferably less than or equal to 0.045 or less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.02.

[0074] Preferably, the rolling stability of the operating process can be further improved if a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi‖ less than or equal to 0.99, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.01.

[0075] Preferably, a further improvement in rolling stability can be achieved if a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi‖ less than or equal to 0.75, more preferably less than or equal to 0.6, more preferably less than or equal to 0.45, more preferably less than or equal to 0.32, and most preferably less than or equal to 0.15. According to a preferred embodiment, a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi‖ less than or equal to 0.1, further preferably less than or equal to 0.075, more preferably less than or equal to 0.06, more preferably less than or equal to 0.045 and particularly preferably less than or equal to 0.032 or less than or equal to 0.02 or less than or equal to 0.015.

[0076] For an operating process comprising at least i + 1 forming process steps, the rolling stability can optionally also be improved if the metallic rolled stock passes through a rolling stand in a j-th forming process step from a set of j = 1 to i forming process steps, preferably from a set of j = 2 to i forming process steps, and further preferably from a set of j = 3 to i forming process steps, wherein the metallic rolled stock does not undergo a normalized relative thickness change in the j-th forming process step. ‖Δhj‖=ΔhjΔhk with Δhj=hzu,j−hab,jhzu,j learns.

[0077] Here it is proposed that the metallic rolled stock does not experience any thickness reduction during the j-th forming process step. In such a case, one can also speak of an open rolling stand, which the metallic rolled stock merely passes through. Since the metallic rolled stock does not experience any thickness reduction during the j-th forming process step, the normalized relative thickness reduction is, by definition, set to 0, i.e., ||Δh j || = 0.

[0078] For an operating process comprising at least i + 1 forming process steps, the rolling stability can be further improved if the metallic rolled stock passes through a rolling stand in a l-th forming process step from a set of l = 1 to i forming process steps, wherein the l-th forming process step is not equal to the j-th forming process step, preferably from a set of l = 2 to i forming process steps and further preferably from a set of l = 3 to i forming process steps, wherein the metallic rolled stock does not undergo a normalized relative thickness change ||Δh in the l-th forming process step. l || ‖Δhl‖=ΔhlΔhk with Δhl=hzu,l−hab,lhzu,l learns.

[0079] It is additionally proposed here that the metallic rolled stock also experiences no thickness reduction in an l-th forming process step. Here too, the normalized relative thickness reduction is, by definition, equated to 0, i.e., ||Δh1|| = 0.

[0080] Optionally, the l-th forming process step can be arranged immediately before or after the j-th forming process step.

[0081] According to an optional embodiment, at least two forming process steps are carried out by a rolling stand, preferably by means of a reversal of the direction of the rolled material within the rolling plant, in particular three, four, five or more forming process steps.

[0082] In other words, at least one rolling stand is operated at least partially in reverse and / or the metallic material being rolled is diverted around at least one rolling stand.

[0083] Optionally, a number of forming process steps can be carried out using at least two, in particular three, four, five, six, seven or more, rolling stands arranged directly adjacent to each other, thus avoiding a reversal of the direction of the rolled material.

[0084] According to one conceivable embodiment, the above-proposed operating method can be carried out on a rolling mill having a unidirectionally operating area, in particular on a rolling mill having a finishing rolling mill.

[0085] However, the operating procedure can also be carried out on a rolling mill which has a reversing roughing mill and a unidirectional finishing mill.

[0086] According to a particularly preferred embodiment, a microstructure parameter, preferably a grain size, a recrystallized volume fraction and / or a phase fraction, of the metallic rolled material is measured during the operating process, preferably after the nth forming process step.

[0087] A phase component may contain, among other things, ferrite components, pearlite components and / or bainite components.

[0088] The measurement of the microstructure can advantageously be carried out after a pre-rolling mill, after the i-th, i.e. any forming process step, and / or after the n-th, i.e. the last, forming process step and / or after a cooling section, in particular after a cooling section following the n-th forming process step.

[0089] Furthermore, the measurement of the microstructure parameter can be carried out simultaneously during the execution of the operating procedure, or on a previous metallic rolled product, and / or based on a measurement in a laboratory and thus after the execution of the operating procedure.

[0090] Rolling stability can be further improved by choosing a ratio of two normalized relative thickness reductions depending on at least one microstructure parameter, in particular the ratio of the normalized relative thickness reductions. ‖Δhi−1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+2‖ and / or the ratio of the normalized relative thickness reductions

[0091] Optionally, the i-th forming process step corresponds to the 3rd forming process step or is subsequent to it, preferably to the 4th forming process step and particularly preferably to the 5th forming process step.

[0092] Preferably, the i-th forming process step corresponds to or precedes the 7th forming process step, preferably the 6th forming process step, and particularly preferably the 5th forming process step.

[0093] According to a second aspect of the invention, the problem is solved by a control device set up for carrying out an operating procedure for operating a rolling mill for rolling a metallic rolled material according to the first aspect of the invention.

[0094] It is understood that the advantages of an operating method according to the first aspect of the invention also extend directly to a control device set up for carrying out an operating method for operating a rolling mill for rolling a metallic rolled material according to the first aspect of the invention.

[0095] A control device, which is set up to carry out an operating procedure for operating a rolling mill for rolling a metallic rolled material according to the first aspect of the invention, is preferably data-connected to the rolling mill, in particular it can transmit all relevant control variables to the rolling mill, especially to the rolling stand or to the rolling stands of the rolling mill.

[0096] The control device can be data-connected to a higher-level control and / or regulation unit for planning the forming process steps.

[0097] The control device may include an electronic data processing and / or evaluation unit. Furthermore, the control device may include a data storage device.

[0098] Within the framework of process control, the control device can have a process control system for the units involved in the rolling process or be part of such a process control system.

[0099] The control device can be data-connected to a measuring device, in particular a sensor, especially a sensor for a grain size, a recrystallized volume fraction and / or a phase fraction of the metallic rolled material.

[0100] Optionally, the control device includes at least one process model for determining a stitch plan for forming process steps.

[0101] The at least two forming process steps can be part of a staking plan, which includes the overall forming of the metallic rolled material and the forming process steps involved.

[0102] According to a preferred embodiment, the control device comprises at least one process model for determining temperature control and / or forming control and / or buckling resistance, in particular the temperature control before a forming process step, between two forming process steps, and / or after a forming process step. Based on the results of the process model, control and / or regulation parameters can be adapted in a target-oriented manner.

[0103] It is particularly advantageous if the control device is data-connected to a sensor for a microstructure parameter, in particular to a sensor for a grain size, a recrystallized volume fraction and / or a phase fraction, and data from the sensor are used to set a ratio of two normalized relative thickness reductions, in particular the ratio of the normalized relative thickness reductions. ‖Δhi−1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+4‖‖Δhi+3‖.

[0104] According to a third aspect of the invention, the problem is also solved by a rolling mill for rolling a metallic rolled material comprising a control device according to the second aspect of the invention.

[0105] It is understood that the advantages of a control device according to the second aspect of the invention can also be directly transferred to a rolling mill for rolling a metallic rolled material comprising a control device according to the second aspect of the invention.

[0106] It should be noted here that, within the context of the present patent application, indefinite articles and indefinite numerical indications such as "one...", "two...", etc., are generally to be understood as minimum indications, i.e., as "at least one...", "at least two...", etc., unless it is clear from the context or the specific text of a particular passage that only "exactly one...", "exactly two...", etc., is meant.

[0107] It should be noted here that, within the context of the present patent application, the term "in particular" is always to be understood as introducing an optional, preferred feature. The term is not to be understood as "namely" or "namely".

[0108] Further advantages, details and features of the invention will also become apparent from the exemplary embodiments described below.

[0109] Components which are at least essentially identical in their function in the individual figures may be marked with the same reference symbols, although the components do not have to be numbered and explained in all figures.

[0110] The drawing shows: Fig. 1a: schematically showing a rolling mill with a rolling stand for forming a metallic rolled material; Fig. 1b: schematically comprising a rolling mill comprising n rolling stands for forming a metallic rolled material, wherein the rolling mill is set up for unidirectional forming of the metallic rolled material along a machine direction; Fig. 1c: schematically comprising a rolling mill comprising a rolling stand for forming a metallic rolled material, wherein the rolling mill is set up to carry out a plurality of forming process steps in reverse on a single rolling stand; Fig. 1d: schematically a rolling mill with an open rolling stand, which is passed by a metallic rolled material; Fig. 2a: schematically a rolling mill with an arrangement of 7 rolling stands, which are connected to a control device via signaling; Fig. 2b: schematically a first embodiment of the operating procedure proposed here; Fig. 2c: schematically a second embodiment of the operating procedure proposed here; Fig. 3a: schematically a third embodiment of the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line); Fig. 3b: schematically a fourth embodiment of the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line); Fig. 3c: schematically a fifth embodiment of the operating method proposed here (white bars, solid line) in comparison to an operating method from the prior art (black bars, dashed line); Fig. 3d: schematically a sixth embodiment of the operating method proposed here (white bars, solid line) in comparison to an operating method from the prior art (black bars, dashed line); Fig. 3e: schematically, a seventh embodiment of the operating method proposed here (white bars, solid line) in comparison to an operating method from the prior art (black bars, dashed line); and Fig. 3f: schematically an eighth embodiment of the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line).

[0111] The rolling mill 10 in Fig. 1a has a rolling stand 12 and is set up for forming a metallic rolled stock 1 by means of an i-th forming process step. The metallic rolled stock has a thickness h in the i-th forming process step. zu,i into a roll gap (not designated) of the rolling stand 12 and leaves the roll gap in a deformed state with a thickness h ab,i .

[0112] The relative decrease in thickness Δh i The following results are obtained by the deformation of the metallic rolled material 1 by the i-th deformation process step using the calculation rule: Δhi=hzu,i−hab,ihzu,i.

[0113] The rolling mill 10 in Fig. 1b has a number n of rolling stands 12. The rolling mill 10 consists of Fig. 1a is set up for the unidirectional forming of a metallic rolled material 1 by means of n forming process steps, wherein one forming process step can be carried out on each rolling stand 12 with a running variable i = 1 to n.

[0114] For example, in Fig. 1b A rolling stand 12 is marked with an i, which is intended to clarify that the i-th forming process step of the metallic rolled material 1 is carried out on this rolling stand 12. Beforehand, the metallic rolled material is subjected to an (i-1)-th forming process step analogous to this, and afterwards to an (i+1)-th forming process step.

[0115] One of the i = 1 to n forming process steps exhibits the greatest relative thickness reduction among the preceding set of forming process steps. This forming process step is referred to as the k-th forming process step in this description. The relative thickness reduction for this k-th forming process step is calculated as follows: Δhk=hzu,k−hab,khzu,k.

[0116] It should be explicitly noted again that the k-th forming process step also belongs to the set of i = 1 to n forming process steps. It can therefore additionally and specifically also be designated as the i-th, (i-1)-th, or (i+1)-th forming process step. The designation as the k-th forming process step serves only to normalize the relative thickness reductions of the i = 1 to n forming process steps.

[0117] The normalized relative thickness reduction of the i-th forming process step ||Δh i|| results from the quotient of the relative thickness reduction of the i-th forming process step Δh i and the relative thickness reduction of the k-th forming process step Δh k and can therefore be calculated as follows: ‖Δhi‖=ΔhiΔhk.

[0118] Even if this is the case in the exemplary embodiment of the Fig. Since 1b is not shown, in a different embodiment (not shown here) no relative thickness reduction can occur at a rolling stand 12. In other words, in such a case, the metallic rolled material 1 passes through a rolling stand without experiencing a relative thickness reduction. If this were the case at the i-th forming process step, the normalized relative thickness reduction for the i-th rolling stand 12 would, by definition, be ‖Δhi‖=0.

[0119] The rolling mill 10 in Fig. 1c has exactly one rolling stand 12 and is set up for forming a metallic rolled stock (not shown) with the i = 1 to n = 5 forming process steps involving a reversal of the direction of the metallic rolled stock. In this case, one also speaks of reversing forming process steps of the metallic rolled stock.

[0120] The rolling mill 10 in Fig. Figure 1d has a rolling stand 12 through which a metallic rolled stock 1 passes, bypassing any deformation. In other words, the rolling stand 12 is open, such that the roll gap (not specified) is greater than or equal to the thickness h. zu,j of the incoming metallic rolled material 1. An i-th forming process step can also be referred to as a j-th forming process step or as an l-th forming process step within the scope of this description. Accordingly, the following applies here: hzu,j=hab,j and ‖Δhj‖=0.

[0121] The Fig. Figure 2a schematically shows a rolling mill 10 with an arrangement of 7 rolling stands 12, each of which is connected to a control device 20 via a signal system. The rolling mill 10 is configured for forming a metallic rolled stock (not labeled) in a unidirectional direction, such that the metallic rolled stock passes through one rolling stand 12 after the other, completing one forming process step in each stand. However, it is also possible for the metallic rolling stock to pass through one or more rolling stands 12 without any open movement, so that a forming process step i = 1 to n occurs at these rolling stands 12, but no relative change in thickness takes place.

[0122] Each rolling stand 12 is signal-connected to the control device 20. Therefore, each rolling stand 12 can receive the signals necessary for carrying out the proposed operating procedure from the control device 20. The rolling stands 12 can also (shown as dashed lines) send signals back to the control device 20 in order to make appropriate corrections to the proposed operating procedure, for example, for control purposes.

[0123] The control device 20 has at least one process model 22 with which a step plan for the forming process steps can be determined. Additionally, the control device 20 can have a process model 24 which is configured to determine the temperature profile of the rolled metal.

[0124] The control device 20 can be designed such that the calculations of one or more process models 22, 24 are performed within the control device 20 itself. Alternatively or additionally, the calculations of the process models 22, 24 can be designed such that the calculation takes place within a separate computing unit (not shown), which is then coupled to the control device 20 and transmits the necessary data.

[0125] The control device 20 can alternatively or additionally have a microstructure model (not shown), a friction model (not shown) and / or a different model (not shown).

[0126] The control device 20 can be equipped with a sensor 25 for recording structural parameters.

[0127] The Fig. 2b schematically shows an embodiment of the operating method proposed here, wherein the Fig. 2a schematically depicted rolling mill 10 is used as a basis.

[0128] In the depicted forming process steps i = 1 to n = 7, the metallic rolled stock (not shown) is formed. The greatest relative thickness reduction occurs in the first forming process step, so the normalized relative thickness reduction of the first forming process step ||Δh1|| = 1. Accordingly, the first forming process step also corresponds to the k-th forming process step.

[0129] In this embodiment, the third forming process step corresponds to the i-th forming process step, so that, according to the operating procedure proposed here, the normalized relative thickness reduction ||Δh i-1 || of the (i - 1)th forming process step smaller than the normalized relative thickness reduction ||Δh l || of the i-th forming process step.

[0130] The Fig. 2c schematically shows another embodiment of the operating method proposed here, again using the elements described in the Fig. 2a schematically depicted rolling mill 10 is used as a basis.

[0131] In the depicted forming process steps i = 1 to n = 7, the metallic rolled stock (not shown) is formed. In this embodiment, the highest relative thickness reduction ||Δh2||=1 occurs in the second forming process step. Accordingly, the second forming process step here also corresponds to the k-th forming process step.

[0132] In the present case, the third forming process step and the fourth forming process step fulfill the condition of the operating procedure proposed here, according to which the normalized relative thickness reduction ||Δh i-1 || of the (i - 1)th forming process step smaller than the normalized relative thickness reduction ||Δh l || of the i-th forming process step.

[0133] In this exemplary embodiment, the fourth forming process step is designated as the i-th forming process step.

[0134] It becomes clear that the relative thickness decrease ||Δh i-1 || of the (i-1)-th forming process step with less than the normalized relative thickness reduction ||Δh l || of the i-th forming process step.

[0135] It also shows that a standardized relative decrease in thickness ‖Δhi+1‖=Δhi+1Δhk with Δhi+1=hzu,i+1−hab,i+1hzu,i+1 of the (i+1)-th - in this case the fifth - forming process step less than or equal to the normalized relative thickness reduction ||Δh l || of the i-th forming process step.

[0136] Furthermore, it is also shown that a normalized relative decrease in thickness ‖Δhi+2‖=Δhi+2Δhk with Δhi+2=hzu,i+2−hab,i+2hzu,i+2 of the (i + 2)-th - in this case the sixth - forming process step less than or equal to the normalized relative thickness reduction ||Δh i+1 || of the (i+1)th forming process step.

[0137] Fig. Figure 3a schematically shows a third embodiment with i = 1 to n = 7 forming process steps for the operating method proposed here (white bars, solid line) in comparison to an operating method from the prior art (black bars, dashed line), which has been improved in this case with regard to rolling stability.

[0138] In this third embodiment, the first forming process step corresponds to the forming process step with the greatest relative thickness reduction for the new operating method proposed here. It is evident that the fifth forming process step, according to the newly proposed operating method, exhibits a greater normalized relative thickness reduction than the preceding fourth forming process step, whereas in the previously known operating method, there is a continuous decrease in the normalized relative thickness reduction for each forming process step i = 1 to n = 7.

[0139] A subsequent analysis of the formed metallic rolled stock yielded the microscopic structural parameters shown in Table 2. It is evident that with the proposed operating procedure, both the austenite grain size and the ferrite grain size decrease, while the overall microstructural homogeneity increases. According to the proposed operating procedure, this change in the microstructural parameters leads to an increase in the yield strength, tensile strength, and toughness.

[0140] Table 2: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product (Mn-Nb microalloyed steel, final thickness 2 mm, final rolling temperature 890°C, width 1,550 mm); yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; state of the art corresponds to the current part of rolling practice.

[0141] Fig. Figure 3b schematically shows a fourth embodiment with i = 1 to n = 7 forming process steps for the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line), which has been improved in this case with regard to rolling stability.

[0142] In this fourth embodiment, the fourth forming process step corresponds to the forming process step with the greatest relative thickness reduction for the new operating method proposed here. It is evident that the fourth forming process step, according to the newly proposed operating method, exhibits a significantly greater normalized relative thickness reduction than the preceding third forming process step, whereas in the previously known operating method, there is a continuous decrease in the normalized relative thickness reduction for each forming process step i = 1 to n = 7.

[0143] The second forming process step also shows a change compared to known rolling practice, since the second forming process step also exhibits a larger normalized relative thickness reduction than the first forming process step.

[0144] A subsequent analysis of the formed metallic rolled material yielded the microscopic structural parameters according to Table 3, which again showed an improvement for all investigated parameters.

[0145] Table 3: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product (LC Nb-Ti microalloyed steel, final thickness 3 mm, final rolling temperature 920°C, width 1,900 mm); yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; state of the art corresponds to the current part of rolling practice.

[0146] Fig. Figure 3c schematically shows a fifth embodiment with i = 1 to n = 7 forming process steps for the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line), which has been improved in this case with regard to rolling stability.

[0147] The previously known operating method has the special feature in this fifth embodiment that the fifth and seventh rolling stands are traversed openly by the metallic rolled material, i.e., without experiencing a relative change in thickness in these rolling stands.

[0148] In this fifth embodiment, the first forming process step corresponds to the forming process step with the greatest relative thickness reduction for the new operating method proposed here.

[0149] The operating procedure proposed here also features a total of two open rolling stands, namely the third and seventh forming process steps.

[0150] It is evident that the fifth forming process step according to the newly proposed operating procedure exhibits a greater normalized relative thickness reduction than the preceding fourth forming process step, whereas in the previously known operating procedure - with the exception of the forming process steps at the open rolling stands - there is a continuous decrease in the normalized relative thickness reduction for each forming process step i= 1 to n = 7.

[0151] A subsequent analysis of the formed metallic rolled material yielded the microscopic structural parameters according to Table 4, which again shows an improvement for all investigated parameters.

[0152] Table 4: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product (C Nb microalloyed steel, final thickness 10 mm, final rolling temperature 850°C, width 1,530 mm); yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; state of the art corresponds to the current part of rolling practice.

[0153] Fig. Figure 3d schematically shows a sixth embodiment with i = 1 to n = 7 forming process steps for the operating method proposed here (white bars, solid line) in comparison to an operating method from the prior art (black bars, dashed line), which has been improved in this case with regard to rolling stability.

[0154] The previously known operating method, similar to the fifth embodiment, again has the special feature that the fifth and seventh rolling stands are openly traversed by the metallic rolled material, i.e., without experiencing a relative change in thickness in these rolling stands.

[0155] In this sixth embodiment, the first forming process step again corresponds to the forming process step with the greatest relative thickness reduction for the new operating method proposed here.

[0156] The operating procedure proposed here also features a total of two open rolling stands, namely the second and seventh forming process steps.

[0157] It is evident that the fifth forming process step according to the newly proposed operating procedure exhibits a greater normalized relative thickness reduction than the preceding fourth forming process step, whereas in the previously known operating procedure - with the exception of the forming process steps at the open rolling stands - there is a continuous decrease in the normalized relative thickness reduction for each forming process step i = 1 to n = 7.

[0158] A subsequent analysis of the formed metallic rolled material yielded the microscopic structural parameters according to Table 5, which again shows an improvement for all investigated parameters.

[0159] Table 5: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product (C Nb-Ti microalloyed steel, final thickness 10 mm, final rolling temperature 875°C, width 1,530 mm); yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; state of the art corresponds to the current part of rolling practice.

[0160] Fig. Figure 3e schematically shows a seventh embodiment with i = 1 to n = 7 forming process steps for the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line), which has been improved in this case with regard to rolling stability.

[0161] In this seventh embodiment, the second forming process step corresponds to the forming process step with the greatest relative thickness reduction for the new operating method proposed here. It is evident that the second forming process step according to the newly proposed operating method exhibits a significantly greater normalized relative thickness reduction than the preceding first forming process step, whereas in the previously known operating method, there is a continuous decrease in the normalized relative thickness reduction for each forming process step i = 1 to n = 7.

[0162] It is proposed here to pass through the sixth and seventh rolling stands openly, deviating from the state of the art, and not to cause any relative thickness reduction with these rolling stands.

[0163] A subsequent analysis of the formed metallic rolled material yielded the microscopic structural parameters according to Table 6, which again shows an improvement for all investigated parameters.

[0164] Table 6: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product (Mn-Nb-V-Ti microalloyed steel, final thickness 8-15 mm, final rolling temperature 840-880°C, width 1,550 mm); yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; state of the art corresponds to the current part of rolling practice.

[0165] Fig.Figure 3f schematically shows an eighth embodiment with i = 1 to n = 7 forming process steps for the operating procedure proposed here (white bars, solid line) in comparison to an operating procedure from the prior art (black bars, dashed line), which has been improved in this case with regard to rolling stability.

[0166] In this eighth embodiment, the second forming process step corresponds to the forming process step with the greatest relative thickness reduction for the new operating method proposed here. It is evident that both the second forming process step according to the newly proposed operating method and the fourth forming process step exhibit a greater normalized relative thickness reduction than the immediately preceding forming process steps, whereas in the previously known operating method, there is a continuous decrease in the normalized relative thickness reduction for each forming process step i = 1 to n = 7.

[0167] A subsequent analysis of the formed metallic rolled material yielded the microscopic structural parameters according to Table 7, which again shows an improvement for all investigated parameters.

[0168] Table 7: Qualitative effects of the proposed operating procedure on macroscopic and / or microscopic properties of a metallic rolled product (Mn-Nb-V-(Mo)-Ti microalloyed steel, final thickness 2.5 mm, final rolling temperature 870°C, width 1,100 mm); yield strength, tensile strength and / or toughness: + corresponds to higher values, - corresponds to lower values; austenite grain size and / or ferrite grain size: + corresponds to higher values ​​for grain size, - corresponds to lower values ​​for grain size; microstructure homogeneity: + corresponds to a more homogeneous microstructure, - corresponds to a more inhomogeneous microstructure; state of the art corresponds to the current part of rolling practice. Reference symbol list 1 metallic rolled product 10 rolling mill 12 Rolling mill 20 Control device 22 Process model for determining a staking plan 24 Process model for determining a temperature profile 25 Sensor n Number of forming process steps i Running variable of the 1 to n forming process steps j Running variable of the 1 to n forming process steps k Running variable of the 1 to n forming process steps l Running variable of the 1 to n forming process steps h zu,i Thickness of the metallic rolled material when it enters the rolling stand belonging to the i-th forming process step h zu,j Thickness of the metallic rolled material when running onto the rolling stand belonging to the j-th forming process step h zu,k Thickness of the metallic rolled material when running onto the rolling stand belonging to the k-th forming process step h zu,l Thickness of the metallic rolled material when running onto the rolling stand belonging to the 1st forming process step h ab,i Thickness of the metallic rolled material as it exits the rolling stand belonging to the i-th forming process step hab,j Thickness of the metallic rolled material as it exits the rolling stand belonging to the j-th forming process step h ab,k Thickness of the metallic rolled material as it enters the rolling stand belonging to the k-th forming process step h ab,l Thickness of the metallic rolled material as it exits the rolling stand belonging to the 1st forming process step Relative thickness reduction of an i-th forming process step Relative thickness reduction of the k-th forming process step normalized relative thickness reduction of an i-th forming process step

Claims

[1] Operating method for a rolling mill (10), preferably a hot rolling mill, comprising at least one rolling stand (12), preferably two, three, four, five, six, seven, eight, nine or more rolling stands (12), for forming a metallic rolled stock (1), in particular a hot strip, by means of at least n = 2 forming process steps in which the metallic rolled stock (1) passes through a rolling stand (12), in particular by means of at least n = 3, n = 4, n = 5, n = 6 or more forming process steps, - where an i-th forming process step from a set of i = 1 to n forming process steps leads to a relative decrease in thickness Δhi=hzu,i−hab,ihzu,i of the metallic rolled material (1) under the influence of a rolling stand (12) or the metallic rolled material (1) passes through a rolling stand (12) without any relative decrease in thickness occurring, wherein the metallic rolled material (1) has a thickness h zu,iapproaching a rolling mill (12) and with a thickness h ab,i expires; - wherein an (i-1)th forming process step is arranged temporally before the i-th forming process step, in particular wherein an (i-2)th forming process step is arranged temporally before the (i-1)th forming process step, in particular wherein an (i-3)th forming process step is arranged temporally before the (i-2)th forming process step; - wherein the operating process comprises a k-th forming process step from a set of k = 1 to n forming process steps, wherein the k-th forming process step is characterized by the fact that the k-th forming process step has the greatest relative thickness reduction Δhk=hzu,k−hab,khzu,k from the set of k = 1 to n of the forming process steps; - where a normalized relative thickness decrease of the i-th forming process step ‖Δhi‖=ΔhiΔhk from the quotient of the relative thickness reduction of the i-th forming process step Δh i and the relative thickness reduction of the k-th forming process step Δh k results in, where the normalized relative thickness reduction of the i-th forming process step ||Δh l || = 0 if no thickness reduction of the metallic rolled material (1) occurs during the i-th forming process step; the operating procedure characterized by is that - for a relative decrease in thickness Δh i-1 > 0 of the (i - 1)th forming process step with Δhi−1=hzu,i−1−hab,i−1hzu,i−1 a normalized relative decrease in thickness ‖Δhi−1‖=Δhi−1Δhk of the (i - 1)th forming process step less than or equal to the normalized relative thickness reduction ||Δh l || of the i-th forming process step is; or - for a relative decrease in thickness Δh i-2 > 0 of the (i -2)-th forming process step with Δhi−2=hzu,i−2−hab,i−2hzu,i−2 with a relative decrease in thickness Δh i-1 =0 0 of the (i - 1)th forming process step a normalized relative decrease in thickness ‖Δhi−2‖=Δhi−2Δhk of the (i-2)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh l || of the i-th forming process step is; or - for a relative decrease in thickness Δh i-3 >0 of the (i-3)-th forming process step with Δhi−3=hzu,i−3−hab,i−3hzu,i−3 with a relative decrease in thickness Δh i-1 = 0 of the (i - 1)th forming process step and with a relative thickness reduction Ah i-2 =0 of the (i-2)-th forming process step a normalized relative thickness reduction ‖Δhi−3‖=Δhi−3Δhk of the (i-3)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i|| of the i-th forming process step. [2] Operating method according to claim 1 comprising n = 3 forming process steps greater than or equal to n, wherein an (i+1)th forming process step is arranged after the i-th forming process step, characterized by , that - a normalized relative decrease in thickness ‖Δhi+1‖=Δhi+1Δhk with Δhi+1=hzu,i+1−hab,i+1hzu,i+1 of the (i+1)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh l || of the i-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi‖‖Δhi+1‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+1‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+1‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.

01. [3] Operating method according to claim 2 comprising n = 4 forming process steps greater than or equal to n, wherein an (i+2)th forming process step is arranged after the (i+1)th forming process step, characterized by , that - a normalized relative thickness reduction thickness reduction ‖Δhi+2‖=Δhi+2Δhk with Δhi+2=hzu,i+2−hab,i+2hzu,i+2 of the (i+2)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i+1 || of the (i+1)-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi+2‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+2‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+2‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.

01. [4] Operating method according to claim 3 comprising n = 5 forming process steps greater than or equal to n = 5, wherein an (i+3)th forming process step is arranged after the (i + 2)th forming process step, characterized by , that - a normalized relative decrease in thickness ‖Δhi+3‖=Δhi+3Δhk with Δhi+3=hzu,i+3−hab,i+3hzu,i+3 of the (i+3)-th forming process step less than or equal to the normalized relative thickness reduction ||Δh i+2 || of the (i+2)-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+3‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+3‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+3‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.

01. [5] Operating method according to claim 3 comprising n = 6 forming process steps greater than or equal to 6, wherein an (i+4)th forming process step is arranged after the (i + 3)th forming process step, characterized by , that - a normalized relative decrease in thickness ‖Δhi+4‖=Δhi+4Δhk with Δhi+4=hzu,i+4−hab,i+4hzu,i+4 of the (i+4)th forming process step less than or equal to the normalized relative thickness reduction ||Δh i+3 || of the (i+3)-th forming process step is, preferably is a ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+4‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+4‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi+4‖ less than or equal to 1.0, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.

01. [6] Operating procedures according to any of the foregoing claims, characterized by , that - the operating procedure includes an (i-2)-th forming process step with a normalized relative thickness reduction ‖Δhi−2‖=Δhi−2Δhk with Δhi−2=hzu,i−2−hab,i−2hzu,i−2 exhibits; and - preferably a ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - preferably a ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ less than or equal to 1.0, preferably less than or equal to 0.2 and particularly preferably greater than or equal to 0.

01. [7] Operating method according to claim 6, characterized by , that - the operating procedure includes an (i-3)-th forming process step with a normalized relative thickness reduction ‖Δhi−3‖=Δhi−3Δhk with Δhi−3=hzu,i−3−hab,i−3hzu,i−3 exhibits; and - preferably a ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - preferably a ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ less than or equal to 1.0, preferably less than or equal to 0.2 and particularly preferably greater than or equal to 0.

01. [8] Operating method according to claim 7, characterized by , that - the operating procedure includes an (i-4)th forming process step with a normalized relative thickness reduction ‖Δhi−4‖=Δhi−4Δhk with Δhi−4=hzu,i−4−hab,i−4hzu,i−4 exhibits; and - preferably a ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ greater than or equal to 1.0, preferably greater than or equal to 2.0 and particularly preferably greater than or equal to 6.0; and / or - preferably a ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ less than or equal to 1.0, preferably less than or equal to 0.2 and particularly preferably greater than or equal to 0.

01. [9] Operating procedures according to any of the foregoing claims, characterized by , that a ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi‖ less than or equal to 0.99, preferably less than or equal to 0.2 and especially preferably less than or equal to 0.

01. [10] Operating process according to one of the preceding claims comprising at least i+1 forming process steps, characterized by , that the metallic rolled stock (1) passes through a rolling stand (12) in a j-th forming process step from a set of j = 1 to i forming process steps, preferably from a set of j = 2 to i forming process steps and further preferably from a set of j = 3 to i forming process steps, wherein the metallic rolled stock (1) does not undergo a normalized relative thickness change in the j-th forming process step ‖Δhj‖=ΔhjΔhk with Δhj=hzu,j−hab,jhzu,j learns. [11] Operating method according to any of the preceding claims, in particular operating method according to claim 10, comprising at least i+1 forming process steps, characterized by, that the metallic rolled stock (1) passes through a rolling stand (12) in a l-th forming process step from a set of l = 1 to i forming process steps, wherein the l-th forming process step is not equal to the j-th forming process step, preferably from a set of l = 2 to i forming process steps and further preferably from a set of l = 3 to i forming process steps, wherein the metallic rolled stock (1) does not undergo a normalized relative thickness change in the l-th forming process step ‖Δhl‖=ΔhlΔhk with Δhl=hzu,l−hab,lhzu,l learns. [12] Operating method according to any of the foregoing claims, characterized by , that at least two forming process steps are carried out by a rolling stand (12), preferably by means of a reversal of direction of the rolled material (1) within the rolling plant (10), in particular three, four, five or more forming process steps. [13] Operating method according to any of the foregoing claims, characterized by , that a plurality of forming process steps are carried out by means of at least two, in particular three, four, five, six, seven or more, rolling stands (12) arranged directly adjacent to each other, without reversing the direction of the rolled material (1). [14] Operating method according to any of the foregoing claims, characterized by , that a structural characteristic, preferably a grain size, a recrystallized volume fraction and / or a phase fraction, of the metallic rolled material (1) is measured, preferably after the nth forming process step. [15] Operating method according to claim 14, characterized by , that a ratio of two normalized relative thickness reductions is chosen depending on at least one microstructure parameter, in particular the ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions and / or the ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+4‖‖Δhi+3‖. [16] Operating method according to any of the foregoing claims, characterized by that the i-th forming process step corresponds to or follows the 3rd forming process step, preferably the 4th forming process step and particularly preferably the 5th forming process step. [17] Operating method according to any of the foregoing claims, characterized by that the i-th forming process step corresponds to or precedes the 7th forming process step, preferably the 6th forming process step and particularly preferably the 5th forming process step. [18] Control device (20) configured to carry out an operating procedure for operating a rolling mill (10) for rolling a metallic rolled material (1) according to one of the preceding claims. [19] Control device (20) according to claim 18, characterized by , that the control device (20) has at least one process model (22) for determining a stitch plan for forming process steps. [20] Control device (20) according to one of claims 18 or 19, characterized by, that the control device (20) has at least one process model (24) for determining a temperature control and / or a forming control and / or a buckling safety, in particular the temperature control before a forming process step, between two forming process steps and / or after a forming process step. [21] Control device (20) according to one of claims 18 to 20, characterized by , that the control device (20) is data-connected to a sensor (25) for a microstructure parameter, in particular to a sensor for a grain size, a recrystallized volume fraction and / or a phase fraction, and data from the sensor are used to set a ratio of two normalized relative thickness reductions, in particular the ratio of the normalized relative thickness reductions ‖Δhi−1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−2‖‖Δhi−1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−3‖‖Δhi−2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi−4‖‖Δhi−3‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+1‖‖Δhi‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+2‖‖Δhi+1‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+3‖‖Δhi+2‖ and / or the ratio of the normalized relative thickness reductions ‖Δhi+4‖‖Δhi+3‖.

22. Rolling mill (10) for rolling a metallic rolled material (1) comprising a control device (20) according to one of claims 18 to 21.

Images