EP2548665A1 - Method for determining the wear on a roller dependent on relative movement - Google Patents

Abstract

The method involves determining roll goods variable (S2) and determining a sliding zone for each of roll goods section based on a set of process variables. The process variables are arranged in connection with roller structure variables of a roller structure. A respective relative movement dependent wear component is determined by taking length of respective sliding zone into account. A relationship is determined for the respective relative movement dependent wear component. Independent claims are also included for the following: (1) a computer program having a set of instructions for performing a method for investigating wear of a roller (2) a rolling mill.

Description

• wobei während des Walzens des Walzgutes im ersten Walzgerüst den Walzvorgang beschreibende Prozessgrößen entgegen genommen werden,
• wobei anhand der Prozessgrößen in Verbindung mit das erste Walzgerüst beschreibenden Walzgerüstgrößen und das Walzgut beschreibenden Walzgutgrößen in Echtzeit der Verschleiß der Walze des ersten Walzgerüsts ermittelt wird,
• wobei der ermittelte Verschleiß für Walzgutabschnitte des Walzgutes jeweils einen relativbewegungsabhängigen Verschleißanteil umfasst.

The present invention relates to a determination method for a wear of a roll of a first roll stand for rolling rolling stock,

• wherein, during the rolling of the rolling stock in the first roll stand, process variables describing the rolling operation are received,
• wherein the wear of the roll of the first roll stand is determined in real time on the basis of the process variables in connection with roll stand sizes describing the rolling stand and the rolling stock describing the rolling stand,
• wherein the determined wear for Walzgutabschnitte of the rolling stock each comprises a relatively movement-dependent wear component.

The present invention further relates to a computer program which comprises machine code which can be processed directly by a computer and whose execution by the computer causes the computer to carry out such a determination method.

The present invention further relates to a computer adapted to carry out such a determination method.

The present invention further relates to a rolling mill which comprises at least one roll stand for rolling rolling and which is equipped with such a computer.

When rolling metals occurs on the rollers wear. The extent to which wear occurs depends on various parameters. For example, the amount of wear depends on the type of rollers (work roll, back-up roll, etc.), the type of rolling (cold rolling or hot rolling), the arrangement of the rolls in the rolling mill (first, second, third rolling stand of the rolling mill, etc.) or - in the case of a reversing mill - the stitch number, the material of the rolling stock (steel, aluminum, copper, ...), the material of the rolls ( Cast iron, cast steel, high speed steel, ...) etc.

The wear has an impact on the quality of rolled rolled stock. In particular, the wear must be taken into account and, if possible, compensated for by appropriate adjustments to the setting - if necessary also with regard to profile and flatness - for flat rolled stock. Furthermore, the rollers must be changed from time to time and reground.

A direct measurement of the roller wear is only possible if the relevant roller is removed from the rolling stand and can be measured. In the ongoing rolling process, however, a direct measurement of the roller wear is not possible. However, it is known to detect process variables of the rolling process and to account for the roll wear by means of a wear model in real time. By means of the wear model, the wear of the respective roller is determined as a function of the rolled section of the rolling stock, the course of the rolling force over this distance, etc. The wear model makes the determined wear available to other control systems, for example for the corresponding correction of the employment. It is also known to carry out similar calculations offline. The process variables used in this case may be, for example, model-based expected expected quantities.

More recently, the realization has prevailed that the wear can have different wear components, in particular a thermal wear component and a relatively motion-dependent wear component. The thermal wear component is essentially due to the intermittent heating of the roller during contact with the hot Rolling and cooling the roller between the contact times caused. The relative movement-dependent wear component is caused by the relative movement between rolling stock and roller (lead and lag). In particular, it causes an abrasion of the roller (abrasive wear portion).

For the modeling of the thermal wear component, various approaches are known. By way of example, the technical paper " Increasing work-roll life by improved roll-cooling practice "by PG Stevens et al., Journal of Iron and Steel Institute, January 1971, pages 1 to 11 , referenced. A very good procedure for determining the thermal wear component is in the older European patent application, not previously published on the filing date of the present invention 10 174 341.7 the applicant (filing date 27.08.2010, title "Investigation for a wear of a roller for rolling of rolling stock") described.

The present invention relates to the determination of the relatively movement-dependent wear component. The determination and consideration of the thermal wear component will therefore be discussed in the following.

When ascertaining the correction of the position, it may be necessary to take into account in the prior art also a thermal crown of the roller. The determination and consideration of the thermal crowning is not the subject of the present invention.

As a rule, the determination of the relative movement-dependent wear component takes place according to the relationship $$\mathit{there}=c\cdot \mathrm{\Phi }\cdot \alpha \cdot l$$

DA is the expected relative movement-dependent proportion of wear, c a constant coefficient of wear, Φ the pressure distribution in the nip, α den - for the length of the contact area of rolling stock and roller essentially characteristic - contact angle and 1 the length of the respective Walzgutabschnittes. The wear coefficient c is set appropriately. It may depend on the above parameters.

In practice, however, shows that this approach reflects the actual conditions only inadequate.

The object of the present invention is to provide opportunities to determine the relative movement-dependent wear of the roller in a reliable model-based manner.

The object is achieved by a preliminary investigation with the features of claim 1. Advantageous embodiments of the determination method according to the invention are the subject matter of dependent claims 2 to 13.

• dass anhand der Prozessgrößen in Verbindung mit das erste Walzgerüst beschreibenden Walzgerüstgrößen und das Walzgut beschreibenden Walzgutgrößen für die Walzgutabschnitte jeweils eine Gleitzone ermittelt wird, innerhalb derer das Walzgut unter Relativbewegung zur Walze auf der Walzenoberfläche gleitet, und
• dass der jeweilige relativbewegungsabhängige Verschleißanteil unter Berücksichtigung der Länge der jeweiligen Gleitzone ermittelt wird.

According to the invention, it is provided to design a preliminary method of the type mentioned in the introduction,

• that a sliding zone, within which the rolling stock slides on the roll surface with relative movement to the roll, is determined on the basis of the process variables in connection with the first rolling stand describing rolling stand sizes and the rolling stock describing Walzgutgrößen for rolling stock, and
• the respective relative movement-dependent wear component is determined taking into account the length of the respective sliding zone.

The present invention is thus based on the application of the known fact that during rolling there is a region (adhesive zone) in which the rolling stock abuts (adheres) to the roll without relative movement to the roll, while for relative movement-dependent wear on the roll so-called ground length arrives, ie on the length of the roller in which occurs by the pre and lag of the rolling a relative movement between the roll and rolling.

It is possible to set up a model by means of which the sliding zone is determined directly. Alternatively, it is possible to determine the (total) contact length and the (absolute or relative) length of the adhesive zone and then to determine the sliding zone on the basis of the contact length and the adhesive zone. In particular, models are already known in the prior art, which determine, inter alia, the detention zone. By way of example, the technical paper " Effect of Sliding and Rolling Friction on the Energy-Force Parameters during Hot Rolling in Four-High Stands "by EA Garber et al., Published in Russian Metallurgy (Metally), 2007, No. 6, pp. 484-491 , referenced. Such metals are often used as part of the stitch plan calculation.

The known models are used in the prior art only for the determination of rolling force, rolling moment and overfeed. They determine the variables mentioned using the flow properties of the rolling stock, the coefficient of friction between roller and rolling, the desired stitch loss, the geometry of the rolling stock and the like. However, according to the invention, they can also be used for determining the adhesive zone and thus indirectly the sliding zone, whereby the determination of the relative movement-dependent wear can be made on the basis of the sliding zone.

ermittelt wird, wobei dA der jeweilige relativbewegungsabhängige Verschleißanteil, c ein von den Prozessgrößen unabhängiger Anpassungsfaktor, 1 die Länge des jeweiligen Walzgutabschnitts, L die Länge der Gleitzone und Z eine von den Prozessgrößen abhängige weitere Einflussgröße sind. Durch diese Vorgehensweise kann ein relativ einfaches Verschleißmodell implementiert werden, welches bereits recht gute Ergebnisse liefert.In a preferred embodiment it is provided that the respective relative movement-dependent wear component according to the relationship $$\mathit{there}=c\cdot l\cdot L\cdot Z$$

dA is the respective relative movement-dependent wear component, c an adjustment factor independent of the process variables, 1 the length of the respective rolling stock section, L the length of the sliding zone and Z a further influencing variable dependent on the process variables. By doing so, a relatively simple wear model can be used be implemented, which already delivers quite good results.

In the simplest case, it is possible that the further influencing variable depends on the average pressure in the nip (i.e., the quotient of rolling force and contact surface). This procedure often leads to acceptable to good results. However, it leads to better results if the further influencing variable depends on the (exact) pressure distribution in the nip. The pressure distribution can be determined, for example, based on the mean yield stress or on the maximum of the flow curve (as a function of the degree of deformation).

• dass die Druckverteilung im Walzspalt beim erstmaligen Entgegennehmen der Prozessgrößen anhand der Prozessgrößen in Verbindung mit den Walzgerüstgrößen und den Walzgutgrößen ermittelt wird,
• dass die ermittelte Druckverteilung gespeichert wird,
• dass bei einem späteren Entgegennehmen der Prozessgrößen anhand der Prozessgrößen geprüft wird, ob sich die Prozessgrößen geändert haben, und
• dass in Abhängigkeit davon, ob die Prozessgrößen sich geändert haben oder nicht, die Druckverteilung im Walzspalt anhand der neuen Prozessgrößen in Verbindung mit den Walzgerüstgrößen und den Walzgutgrößen neu ermittelt wird oder die gespeicherte Druckverteilung im Walzspalt verwendet wird.

The determination of the pressure distribution in the nip and the formation of the detention zone are - depending on investigation - very compute-intensive. Preferably, therefore, it is provided

• the pressure distribution in the roll gap is determined when the process variables are accepted for the first time on the basis of the process variables in connection with the roll stand sizes and the rolling stock sizes,
• that the determined pressure distribution is stored,
• that in a later acceptance of the process variables on the basis of the process variables, it is checked whether the process variables have changed, and
• in that, depending on whether the process variables have changed or not, the pressure distribution in the roll gap is newly determined on the basis of the new process variables in conjunction with the roll stand sizes and the rolling stock sizes or the stored pressure distribution in the roll gap is used.

By this procedure, the real-time capability of the determination method according to the invention can be realized with a relatively low computing power.

As an alternative to the pressure distribution in the nip, the further influencing variable may depend on the surface hardness of the roll. For example - as in the older European Patent application 10 174 341.7 explained procedure - the relatively movement-dependent wear component depending on the surface hardness and the yield stress of the rolling stock are determined. Alternatively, the relatively movement-dependent wear component can be determined as a function of both the pressure distribution in the roll nip and the surface hardness of the roll, optionally with additional consideration of the yield stress of the rolling stock. Other approaches are possible.

If the further influencing variable (also) depends on the surface hardness of the roll, it is preferable to determine, based on the process variables in conjunction with the roll stand sizes and the rolling stock sizes, in real time an upper temperature to which the surface of the roll heats up during contact with the rolling stock. The surface hardness of the roller is in this case preferably determined as a function of the determined upper temperature.

Preferably, a rolling gap lubrication is taken into account in the determination of the sliding zone.

It is possible that the determined wear is used as part of the determination of manipulated variables for the first roll stand. Alternatively or additionally, it is possible that the determined wear is used to determine a roll change time. If a determination of a roller change time is made, the determination of the expected wear component may possibly be linked to a future-oriented wear prognosis. Such a wear prediction is in the older European patent application not previously published on the filing date of the present invention 10 174 297.1 (Filing 27.08.2010, title "Operating Procedures for a rolling mill for rolling flat rolling stock with roll wear forecast") the applicant described in detail.

Models for processes in rolling mills are usually faulty. It is therefore customary to adapt them on the basis of acquired (= measured) process variables. If adaptation is also to take place within the framework of the determination method according to the invention, various preferred approaches are possible.

• dass die Prozessgrößen eine beim Walzen des Walzgutes auftretende Walzkraft umfassen,
• dass die Walzkraft erfasst wird,
• dass unter Verwendung einer Fließkurve des Walzgutes eine erwartete Walzkraft ermittelt wird,
• dass der jeweilige relativbewegungsabhängige Verschleißanteil in direkter oder indirekter Abhängigkeit von der Fließkurve ermittelt wird und
• dass die Fließkurve in Abhängigkeit von der erfassten Walzkraft und der erwarteten Walzkraft nachgeführt wird.

For one thing, it is possible

• the process variables comprise a rolling force occurring during rolling of the rolling stock,
• that the rolling force is detected,
• that an expected rolling force is determined using a flow curve of the rolling stock,
• that the respective relative movement-dependent wear component is determined in direct or indirect dependence on the flow curve, and
• that the flow curve is tracked depending on the detected rolling force and the expected rolling force.

• dass die Prozessgrößen eine beim Walzen des Walzgutes auftretende Walzkraft und eine beim Walzen des Walzgutes auftretende Voreilung umfassen,
• dass die Walzkraft und die Voreilung erfasst werden,
• dass unter Verwendung einer Fließkurve des Walzgutes und eines Reibwerts des Walzgutes relativ zur Walze eine erwartete Walzkraft und eine erwartete Voreilung ermittelt werden,
• dass der jeweilige relativbewegungsabhängige Verschleißanteil in direkter oder indirekter Abhängigkeit von der Fließkurve und dem Reibwert ermittelt wird und
• dass die Fließkurve und der Reibwert in Abhängigkeit von der erfassten Walzkraft, der erwarteten Walzkraft, der erfassten Voreilung und der erwarteten Voreilung nachgeführt werden.

On the other hand, it is possible

• the process variables comprise a rolling force occurring during rolling of the rolling stock and an overfeed occurring during rolling of the rolling stock,
• that the rolling force and the lead are detected,
• that an expected rolling force and an expected lead are determined using a flow curve of the rolling stock and a coefficient of friction of the rolling stock relative to the roll,
• that the respective relative movement-dependent wear component is determined in direct or indirect dependence on the flow curve and the coefficient of friction, and
• that the flow curve and the coefficient of friction are tracked depending on the detected rolling force, the expected rolling force, the detected lead and the expected lead.

Preferably, in the latter case, the flow curve is not tracked exclusively based on the rolling force. Farther Preferably, the coefficient of friction is not tracked exclusively on the basis of the lead. Preferably, the tracking of the flow curve is based on both the rolling force and the overfeed. The same applies preferably to the coefficient of friction. In particular, a non-linear optimizer can be used to track the flow curve and the coefficient of friction. Suitable optimizers are known as such. By way of example, the technical paper " Adaptive Rolling Model for a Cold Strip Tandem Mill "by Matthias Kurz et al., AISE 2001 , referenced.

To detect the lead, a device is required by means of which the outlet-side speed of the rolling stock can be detected exactly. For example, the roll stand may be followed by a loop lifter whose role is employed on the rolling stock. The peripheral speed of the looper roller corresponds to a very good approximation of the outlet side speed of the rolling stock. In the case of a heavy-plate reversing mill, the length of the rolling stock can also be measured before (after) the rolling and the lead (lag) can be determined on the basis of the recorded length in conjunction with the duration of the rolling pass and the circumferential distance traveled by the roller during this time ,

The rolling force can - assuming a corresponding measuring device - be detected at each rolling mill. However, it is possible that detection of the lead is implemented only in some rolling mills. In this case, for example, in the case of a rolling stand in which, in addition to the rolling force, the overfeed is also detected (first rolling stand in the sense of claim 11), both the flow curve and the coefficient of friction can be tracked. In the other rolling stands, in which only the rolling force, but not the lead is detected (second rolling stands in the sense of claim 11) can be tracked based on the rolling force only the flow curve. However, it is possible that in the context of determining the wear of the roller of the second Roll stand used coefficient of friction of the rolling stock relative to the roller of the second rolling mill is determined by the tracked for the first rolling stand friction coefficient. In particular, the coefficient of friction of the first roll stand can be adopted or scaled by a factor.

In many cases, the rolling stock first passes through the second mill stand and only then the first mill stand. For example, the second mill stand may be a roughing stand of a roughing mill and the first mill stand may be a finishing stand of a finishing mill.

Furthermore, it is possible to measure the roll after removal of the roll from the roll stand and thus to determine the actual wear of the roll. In this case, the wear model can be adapted offline based on the expected wear determined by the wear model and the measured actual wear.

The object of the invention is further achieved by a computer program of the type mentioned. The computer program is designed in this case such that the processing of the machine code by the computer causes the computer to carry out a determination process with all the steps of a determination method according to the invention.

The object is further achieved by a computer which is designed such that it carries out such a determination process.

The object is further achieved by a rolling mill of the type mentioned, which is equipped with such a computer.

FIG 1

schematisch ein Walzwerk,

FIG 2

ein Ablaufdiagramm,

FIG 3

schematisch einen Walzspalt,

FIG 4 bis 7

Ablaufdiagramme,

FIG 8

schematisch ein Walzwerk und

FIG 9 und 10

Ablaufdiagramme.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which are explained in more detail in conjunction with the drawings. Show here

FIG. 1

schematically a rolling mill,

FIG. 2

a flow chart,

FIG. 3

schematically a roll gap,

4 to 7

Flowcharts,

FIG. 8

schematically a rolling mill and

FIGS. 9 and 10

Flowcharts.

According to FIG. 1 For example, a rolling mill has a plurality of rolling stands 1. Alternatively, the rolling mill - for example, in the case of a reversing mill - have only a single stand 1. In the rolling stands 1, a rolling stock 2 is rolled. The rolling stock 2 is made of metal, such as copper, aluminum, brass or steel. It can alternatively be cold rolled or hot rolled in the roll stand 1, whereby in the context of the present invention as a rule a hot rolling takes place.

The rolling stands 1 have according to FIG. 1 in addition to work rolls 3 support rollers 4 on. The rolling stock 2 is therefore a flat rolling stock, ie a strip or heavy plate. Alternatively, the support rollers 4 could be dispensed with, in particular for the rolling of profiled, rod-shaped or tubular rolling stock 2, ie only the work rolls 3 could be present.

The rolling mill is equipped with a computer 5. The computer 5 can according to the representation of FIG. 1 control the rolling mill, so be designed as a control computer. However, this is not mandatory. The computer 5 is programmed with a computer program 6. The computer program 6 can be supplied to the computer 5, for example via a data carrier 7, on which the computer program 6 is stored in machine-readable form. Purely by way of example, the data carrier 7 is in FIG. 1 shown as a USB memory stick. However, this illustration is not intended to be limiting.

The computer program 6 comprises machine code 8, which can be processed directly by the computer 5. The execution of the machine code 8 by the computer 5 causes the computer 5 to carry out a determination process, which is described below in connection with FIG. 2 is explained in more detail. The programming with the computer program 6 thus effects a corresponding design of the computer 5.

According to FIG. 2 - see supplementary FIG. 1 - Sets the computer 5 in a step S1 for a particular roller 3, 4 - for example, the upper work roll 3 of in FIG. 1 middle rolling mill 1 - the wear d to an initial value d0. The initial value d0 can be made available to the computer 5, for example, by an operator 9 or otherwise. One way of otherwise providing the initial value d0 is, for example, that the initial value d0 is automatically transmitted to the computer 5 from a grinding shop in which the respective roller 3, 4 has been reground.

In a step S2, the control computer 5 becomes known rolling stock W1, which describes the rolling stock 2 to be rolled. The rolling stock sizes W1 include, for example, the chemical composition, the temperature and geometric data of the rolling stock 2. In particular, the geometric data and, as a rule, also the temperature are related to the state in which the rolling stock 2 enters the rolling stand 1 under consideration. In the case of a flat rolling stock 2, the geometric data may in particular include its width and its thickness. The rolling stock sizes W1 can be known to the computer 5 in an analogous manner to the initial value d0.

In a step S3, the computer 5 rolling stand sizes W2 are known, which describe the rolling stand 1 and its rollers 3, 4. The roll stand sizes W2 include, for example, the installation location of the considered roll 3, that is, for example, in the first, second, third, etc. rolling stand 1 of a multi-stand rolling mill. Furthermore, the roll stand sizes include W2 the material of the roll 3 (for example, high speed steel HSS), the type of roll 3 (work roll, back-up roll, intermediate roll, etc.) and the static geometric data (width and diameter) of the considered roller 3. The roll stand data W2 the computer 5 to the rolling stock data W1 analogous manner become known.

In a step S 4, the computer 5 receives process variables P during the rolling of the rolling stock 2 in the rolling stand 1 under consideration. The process variables P describe the rolling process in the rolling stand 1 under consideration. For example, they can be detected completely or partially by means of corresponding measuring sensors and supplied to the computer 5. In particular, the rolling force FW can be detected by means of appropriate load cells easily. In an analogous manner, the speed nW of the considered roller 3 can be detected by means of appropriate sensors, so that in conjunction with the - known - diameter of the considered roller 3 immediately gives the peripheral speed. Alternatively, the process variables P can be determined in whole or in part by calculation. For example, the lead can often only be determined by calculation. If the speed of the rolling stock 2 running out of the roll stand 1 is detected by measurement, however, the lead over can also be determined by the ratio of this speed to the peripheral speed of the roll 3 under consideration. In this case, therefore, it also represents a quantity based on measurements. The speed of the rolling stock 2 running out of the roll stand 1 can be detected, for example, via the rotational speed nS of a loop lifter roll 10, which is positioned behind the rolling mill 1 under consideration to the rolling stock 2. Other process variables P, for example a setting of the roll stand 1 or a lubrication between roll 3 and rolling stock 2, can be known, for example, on the basis of a pass schedule calculation.

In a step S5, the computer 5 uses the process variables P in conjunction with the rolling stock sizes W1 and the rolling stand sizes W2 to determine a roll gap model 11 by means of a roll gap model 11 Glide zone 13 (see FIG. 3 ) and its length L. The sliding zone 13 corresponds - see FIG. 3 - That region of the roll gap within which the rolling stock 2 slides relative to the roller 3 on the roll surface. Within the sliding zone 13, therefore, the rolling stock speed at the location considered is either (namely in the inlet side area) smaller than the peripheral speed of the roller 3 or (namely in the outlet side area) greater than the peripheral speed of the roller concerned 3. The sliding zone 13 is in contrast to one Adhesive zone 14, within which the Walzgutgeschwindigkeit at the considered location is equal to the peripheral speed of the considered roller 3. The sliding zone 13 and the adhesive zone 14 together form a contact region 15 of the roller 3, within which the roller 3 contacts the rolling stock 2. The sliding zone 13 and the detention zone 14 are in FIG. 3 - Purely technical drawing - distinguished by the fact that a speed of the rolling stock 2 is indicated in the inlet-side sliding zone 13 with a small and in the outlet side sliding zone 13 with a large arrow, while the speed of the rolling material 2 indicated in the adhesive zone 14 with an arrow medium size is. When determining the sliding zone 13, the computer 5 preferably takes into account, inter alia, a roller gap lubrication.

zu ermitteln. Gegebenenfalls kann bei der Ermittlung der Gleitzone 13, der Haftzone 14 und/oder des Kontaktbereichs 15 eine Walzenabplattung mit berücksichtigt werden. Zum Ermitteln des Kontaktbereichs 15 und der Haftzone 14 kann insbesondere das Walzspaltmodell 11 verwendet werden. Entsprechende Walzspaltmodelle 11 sind an sich bekannt. Rein beispielhaft wird auf den eingangs genannten Fachaufsatz von Garber et al. verwiesen.There are various possibilities for determining the sliding zone 13. At present, it is preferable first to determine the contact area 15 in a manner known per se-still without distinguishing between sliding zone 13 and detention zone 14, then to determine the detention zone 14 in a manner also known per se, and finally-depending on whether the detention zone 14 as absolute or relative value - the sliding zone 13 according to one of the relationships $$\begin{array}{l}\mathrm{sliding\; zone}\mathrm{=}\mathrm{contact\; area}\mathrm{-}\mathrm{Detention\; zone\; or}\\ \mathrm{sliding\; zone}\mathrm{=}\mathrm{contact\; area}\left(\mathrm{1}\mathrm{-}\mathrm{Haftzon}\right)\end{array}$$

to investigate. Optionally, when determining the sliding zone 13, the adhesive zone 14 and / or the contact region 15 a Walzenabplattung be taken into account. For determining the contact region 15 and the adhesive zone 14, in particular the roll gap model 11 can be used. Corresponding roll gap models 11 are known per se. By way of example, the above-mentioned technical article by Garber et al. directed.

In a step S6, the computer 5 determines a relative movement-dependent wear component dA. The computer 5 determines the relative movement-dependent wear component dA in step S6 taking into account the sliding zone 13 determined in step S5. In particular, the relatively movement-dependent wear component dA is proportional to the length L of the sliding zone 13.

In an optional step S7, the computer 5 determines further wear components, in particular a thermal wear component dT. Although the contact region 15 is generally important for the determination of the second wear components. However, as a rule, it is not necessary to distinguish between sliding zone 13 and detention zone 14. The determination of the thermal wear component dT can be carried out in particular according to the method described in the European patent application mentioned above 10 174 341.7 is explained in detail.

In a step S8, the computer 5 updates the wear d by adding the relative movement-dependent wear component dA and, if applicable, the further wear components dT to the previously accumulated wear d.

In a step S9, the computer 5 utilizes the determined wear d. For example, the computer 5, if he according to the representation of FIG. 1 controls the rolling mill, the determined wear d in the context of the determination of manipulated variables S for the considered rolling stand 1 use. Alternatively or additionally, the computer 5 can compare the determined wear d with a maximum permissible wear and if necessary issue a warning message to the operator 9, in that an exchange of the roller 3 under consideration must take place at a roller change time determined as a function of the wear d. Other approaches are possible.

In a step S10, the computer 5 checks whether the rolling of the rolling stock 2 has ended. If this is not the case, the computer 5 returns to step S4 so that it again executes the steps S4 to S10.

wobei c ein von den Prozessgrößen P unabhängiger Anpassungsfaktor, 1 die Länge des jeweiligen Walzgutabschnitts 16 und Z eine weitere, von den Prozessgrößen P abhängige Einflussgröße sind.It can be seen from the above statements that the computer 5 executes the relative movement-dependent wear component dA and possibly also the further wear components dT only for one rolling stock section 16 which during the relevant pass through the loop consisting of steps S4 to S10 in the considered rolling mill 1 is rolled. The computer 5 therefore determines the relative movement-dependent wear component dA in step S6, as in step S6 of FIG FIG. 2 specified, according to the relationship $$\mathit{there}=c\cdot l\cdot L\cdot Z$$

where c is an adaptation factor independent of the process variables P, 1 the length of the respective rolling stock section 16 and Z are a further influencing variable dependent on the process variables P.

The determination of the further influencing variable Z can take place in various ways. The following will be in connection with FIG. 4 a possible procedure for determining the further influencing variable Z explained.

According to FIG. 4 determines the computer 5 in a step S21 on the basis of the process variables P, the Walzgutgrößen W1 and the roll stand W2 such as the temperature and the chemical composition of the rolling material 2 in conjunction with the geometry of the rolled material 2 and the desired stitch loss, a pressure distribution in the nip. Again, this can be Roll nip model 11 can be used. The design of the roll gap model 11 is known to the person skilled in the art.

In a step S22, the computer 5 uses the process variables P, the rolling stock sizes W1 and the rolling stand sizes W2, such as the roll diameter, the roll speed, the rolling stock geometry and the rolling stock temperature, to determine an upper temperature of the roll 3 under consideration. the temperature at which the surface of the roller 3 under consideration heats up during contact with the rolling stock 2. Corresponding roller models are known to the person skilled in the art. In a step S23, the computer 5 then determines, depending on the upper temperature of the roller 3, a surface hardness of the roller 3 under consideration.

• anhand der Druckverteilung im Walzspalt ermitteln, insbesondere proportional zur Druckverteilung im Walzspalt ermitteln,
• anhand der Oberflächenhärte der betrachteten Walze 3 ermitteln, beispielsweise derart, dass die weitere Einflussgröße Z umso kleiner ist, je größer die Oberflächenhärte ist,
• anhand weiterer Prozessgrößen (insbesondere der Walzspaltschmierung) ermitteln oder
• gemäß einer kombinierten Vorgehensweise ermitteln.

In a step S24, the computer 5 determines the further influencing variable Z. For example, the computer 5, according to the embodiment of step S24, the further influencing variable Z.

• determine the pressure distribution in the roll gap, in particular determine it in proportion to the pressure distribution in the roll gap,
• determine on the basis of the surface hardness of the considered roll 3, for example in such a way that the further influencing variable Z is the smaller, the greater the surface hardness,
• using other process variables (in particular, roller gap lubrication) to determine or
• determine according to a combined procedure.

In step S6, the computer 5 determines the relative movement-dependent wear dA according to the already explained relationship $$\mathit{there}=c\cdot l\cdot L\cdot Z\mathrm{,}$$

The determination of the pressure distribution in the nip is relatively computationally intensive. The procedure of FIG. 4 is therefore preferably according to FIG. 5 designed.

According to FIG. 5 After accepting the process variables P, the computer checks whether the process variables P have changed in a step S31. If this is the case, the computer 5 determines the pressure distribution in the nip in step S21 and stores it in a memory 17 in a step S32 (see FIG FIG. 1 ). If the process variables P have not changed, the computer 5 proceeds from step S31 to a step S33, in which the computer 5 reads the pressure distribution in the roll gap from the memory 17 without re-determination.

When the step S31 is processed for the first time, it must be ensured that the computer transfers to steps S21 and S32. This can be achieved, for example, by the computer 5 setting the process variables P to meaningless values during the initialization, ie even before the first section 16 of the rolling stock 2 is rolled, for example by setting the rolling force FW at the value 0.

If the determination of the relative movement-dependent wear component dA takes place using the yield stress of the rolling stock 2, the coefficient of friction and / or the yield stress are preferably updated from time to time. If the friction coefficient and / or the yield stress are updated outside of the determination method according to the invention-for example, within the framework of a rolling force model or a pass schedule calculation-it is possible to transfer these values to the determination method according to the invention. Alternatively, the determination method for determining the wear d can be adapted. The FIG. 6 and 7 show two preferred approaches.

According to FIG. 6 the computer 5 determines the pressure distribution on the basis of the process variables P, the rolling stock sizes W1 and the rolling stand sizes W2 by means of the roll gap model 11 in a step S41 in the nip, an expected rolling force FW 'and an expected lead v'.

The process variables P usually include, inter alia, the rolling force FW and the advance v. The rolling force FW is usually detected by measurement. However, this rolling force FW, ie the actual rolling force, is not used in the course of step S41. In the execution of step S41, a flow curve of the rolling stock 2 is used instead, which enters both into the determination of the pressure distribution and in the determination of the expected rolling force FW 'and the expected lead v'. Due to the dependence of the relative movement-dependent wear component dA on the pressure distribution in the roll gap, therefore, the relatively movement-dependent wear component dA is determined as a function of the flow curve. Dependence is indirect in this case. Alternatively, a direct dependency might be possible.

The computer 5 can therefore according to FIG. 6 in a step S42, compare the expected rolling force FW 'determined by it with the actual rolling force FW. If (significant) deviations occur, the computer 5 proceeds to a step S43. In step S43, the computer 5 traces the flow curve as a function of the detected rolling force FW and the expected rolling force FW '.

FIG. 7 essentially goes by FIG. 6 out. However, steps S42 and S43 are replaced by steps S46 and S47.

In the embodiment of FIG. 7 It is assumed that, in addition to the rolling force FW, the lead advance v is also available as the actual measured variable, ie it is detected. The determination of the expected advance v 'of the step S41, however, takes place without utilization of the actual advance v. Instead, the expected lead v 'is determined using the flow curve and a coefficient of friction of the rolling stock 2 relative to the roller 3 under consideration. The determination of the expected Rolling force FW 'is carried out as already described using the flow curve.

The friction coefficient is - as well as the flow curve - in the determination of the relative movement-dependent wear dA. In particular, the coefficient of friction enters into the determination of the sliding zone 13. In step S46, therefore, in addition to the rolling force FW and the expected rolling force FW ', the actual lead v and the expected lead v' are compared with each other. If there are significant deviations, the computer 5 proceeds to step S47. In step S47, the calculator 5 traces the flow curve and the coefficient of friction as a function of the rolling force FW, the expected rolling force FW ', the lead v and the expected lead v'. The tracking can be done in particular by means of a non-linear optimizer (not shown in the FIG).

The procedures of the FIG. 6 and 7 can be combined with each other. In particular, it is - see FIG. 8 it is possible for some rolling stands 1 of a multi-stand rolling train to have both the rolling force FW and the lead v as measured process variables P, while for other rolling stands 1 of the rolling train only the rolling force FW, but not the lead v is available as a measured variable , As shown by FIG. 8 For example, in the case of the front rolling stands 1, only the respective rolling force is detected, while in the rear rolling stands 1 both the respective rolling force FW and - via the speeds nS, nH of looper rolls 10 and a reel 18 - the respective lead v are detected.

In order to enable tracking of the coefficient of friction for the rolling stands 1, in which only the rolling force FW, but not also the advance is detected v, the procedures of the FIG. 6 and 7 according to the FIG. 9 and 10 be modified. FIG. 9 Here is a modification of FIG. 7 . FIG. 10 a modification of FIG. 6 ,

According to FIG. 9 For one of the rolling mills 1, in which also the lead v is detected as a measured variable, the tracking friction value is provided in a step S51 for other rolling stands 1. According to FIG. 10 In a step S56, the friction coefficient provided is accepted by a rolling stand 1, in which no overfeed is detected, and a separate coefficient of friction is determined therefrom. For example, the coefficient of friction may be scaled at a suitable factor in step S56.

According to FIG. 8 The rolling stock 2 first passes through those rolling stands 1 in which only the rolling force FW, but not also the overfeed, is written, and only then the rolling stands 1, in which both the rolling force FW and the lead v are detected. In particular, the front rolling stands 1 can be roughing a roughing, the rear rolling stands 1 finishing stands of a finishing train.

The present invention has many advantages. In particular, the procedure according to the invention makes possible a good and reliable prediction of the relatively movement-dependent wear component dA. Furthermore, in particular in connection with the determination of the thermal wear component dT according to the teaching of the European patent application 10 174 341.7 given the opportunity to provide a single wear model 12, which is used for all rolling mills 1 a multi-stand rolling mill. The wear model 12 can in this case according to the representation of FIG. 1 include the roll gap model 11 with. Alternatively, the roll gap model 11 may be located outside of the wear model 12 - for example within a stitch plan calculation. Furthermore, there is an improved sensitivity to process changes, for example, variations in the roll gap lubrication or other changes in the coefficient of friction between rolling stock 2 and considered roller 3. Also, the influence of the rolling gap lubrication on the wear d can be better modeled.

The present invention is preferably applied to hot rolling of flat stock 2. However, it is also applicable to the cold rolling of flat rolling 2. Also, it is both during hot and cold rolling of andersartigem rolling stock 2, for example, rod-shaped rolling 2 or 2 profiled rolling applicable. Furthermore, it has not been discussed above whether the relative movement-dependent wear component dA (and optionally also the further wear components dT are determined in the width direction with or without spatial resolution in the case of a flat rolled stock 2. Of course, both approaches are possible.

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims (16)

Determination method for a wear (d) of a roll (3) of a first roll stand (1) for rolling rolling stock (2), - Wherein during the rolling of the rolling stock (2) in the first rolling stand (1) the rolling process descriptive process variables (P) are received, wherein the wear (d) of the roll (3) of the first roll stand (1) is determined in real time on the basis of the process variables (P) in conjunction with the rolling stand (W2) describing rolling stock (W2) and the rolling stock describing rolling stock (W1) . wherein the determined wear (d) for rolling stock sections (16) of the rolling stock (2) in each case comprises a relative movement-dependent wear portion (dA), wherein a sliding zone (13), within which the rolling stock (13) is determined in each case on the basis of the process variables (P) in conjunction with the first rolling stand (1) describing rolling stand sizes (W2) and Walzgut describing Walzgutgrößen (W1) for the Walzgutabschnitte (16) 2) slides relative to the roller (3) on the roller surface, and - Wherein the respective relative movement-dependent wear component (dA) is determined taking into account the length (L) of the respective sliding zone (13). Determination method according to claim 1,
characterized,
that the respective relative movement-dependent wear component (dA) according to the relationship $$\mathit{there}=c\cdot l\cdot L\cdot Z$$

dA is the respective relative movement-dependent wear component, c an adaptation factor independent of the process variables (P), 1 the length of the respective rolling stock section (16), L the length of the sliding zone (13) and Z another dependent on the process variables (P) Are influencing factor. Determination method according to claim 2,
characterized,
that the further influencing variable (Z) depends on the pressure distribution in the nip. Determination method according to claim 3,
characterized, - that the pressure distribution in the roll gap during the initial accepting of the process variables (P) on the basis of the process variables (P) in conjunction with the roll stand sizes (W2) and the Walzgutgrößen (W1) is determined, - that the determined pressure distribution is stored, - that is checked at a later receipt of the process variables (P) based on the process variables (P), if the process variables (P) have changed, and - That , depending on whether the process variables (P) have changed or not, the pressure distribution in the roll gap on the basis of the new process variables (P) in conjunction with the rolling stand sizes (W2) and Walzgutgrößen (W1) is redetermined or the stored pressure distribution used in the nip. Investigative procedure according to claim 2, 3 or 4, characterized
that the further influencing variable (Z) from the surface hardness of the roller (3) depends. Determination method according to claim 5,
characterized,
that on the basis of the process variables (P) in conjunction with the rolling stand sizes (W2) and the rolling stock sizes (W1) an upper temperature is determined in real time, to which the surface of the roll (3) heats up during contact with the rolling stock (2), and that the surface hardness of the roller (3) is determined as a function of the determined upper temperature. Investigative procedure according to one of the above claims, characterized
that in the determination of the sliding zone (13) a roll gap lubrication is taken into account. Investigative procedure according to one of the above claims, characterized
in that the determined wear (d) is used in the context of the determination of manipulated variables (S) for the first roll stand (1) and / or is used to determine a roll change time. Investigation procedure according to one of Claims 1 to 8, characterized that the process variables (P) include a rolling force (FW) occurring during rolling of the rolling stock (2), - that the rolling force (FW) is detected, that an expected rolling force (FW ') is determined using a flow curve of the rolling stock (2), - That the respective relative movement-dependent wear component (dA) is determined in direct or indirect dependence on the flow curve, and - that the flow curve is tracked depending on the detected rolling force (FW) and the expected rolling force (FW '). Investigation procedure according to one of Claims 1 to 8, characterized that the process variables P comprise a rolling force (FW) occurring during rolling of the rolling stock (2) and an overfeed (v) occurring during rolling of the rolling stock (2), - that the rolling force (FW) and the lead (v) are detected, that an expected rolling force (FW ') and an expected lead (v') are determined using a flow curve of the rolling stock (2) and a coefficient of friction of the rolling stock (2) relative to the roll (3), - That the respective relative movement-dependent wear component (dA) is determined in direct or indirect dependence on the flow curve and the coefficient of friction, and - that the flow curve and the coefficient of friction depending on the detected rolling force (FW), the expected rolling force (FW '), the detected lead (v) and the expected lead (v') are tracked. Determination method according to claim 10,
characterized,
in that with respect to a roll (3) of a second roll stand (1) a determination method analogous to claim 9 is carried out, and in that a coefficient of friction of the rolling stock used in determining the wear (d) of the roll (3) of the second roll stand (1) (2) is determined relative to the roller (3) of the second rolling mill (1) on the basis of the first rolling mill (1) tracked coefficient of friction. Determination method according to claim 11,
characterized,
that the rolling stock (2) first passes through the second rolling stand (1) and only then the first rolling stand (1). Determination method according to claim 12,
characterized,
that the second roll stand (1) is a roughing stand to a roughing train and the first roll stand (1) is a finishing stand of a finishing mill. Computer program comprising machine code (8) which can be processed directly by a computer (5) and whose processing by the computer (5) causes the computer (5) to carry out a preliminary investigation with all the steps of a determination method according to one of the above claims. Computer,
characterized,
that the computer is designed such that it performs a discovery process with all the steps of a preliminary investigation of any of claims 1 to 13. Rolling mill comprising at least one rolling stand (1) for rolling rolling stock (2),
characterized,
that the rolling mill is equipped with a computer (5) according to claim 15.

Images