CN102886385B - Method for determining relative movement-related degree of wear for roller - Google Patents

Abstract

The invention relates to a method for determining the relative motion-related wear of rolls. During rolling of a rolling stock (2) in a rolling stand (1), a process variable (P) describing the rolling process is acquired. The degree of wear (d) of the rolls (3) of the rolling stand (1) is determined in real time on the basis of the process variable in conjunction with the rolling stand variable (W2) describing the rolling stand and the rolling piece variable (W1) describing the rolling stock. The measured wear includes a relative movement-dependent wear component (dA) for a rolling stock section ( 16 ) of the rolling stock. Based on the process variables in combination with the mill stand variable (W2) describing the rolling mill stand and the rolling piece variable (W1) describing the rolled piece, a sliding zone (13) is determined each for the section of the rolling piece in which the rolling The part slides on the surface of the roll while moving relative to the roll. The respective relative movement-related wear component is determined taking into account the length (L) of the respective sliding zone.

Description

Method for determination of relative motion-related wear of rolls

technical field

The invention relates to a method for determining the degree of wear of rolls of a first rolling mill stand for rolling a rolled stock,

- wherein, during rolling of the rolled stock in the first rolling stand, process variables describing the rolling process are acquired,

- wherein the degree of wear of the rolls of the first rolling stand is determined in real time from these process variables in combination with a rolling stand variable describing the first rolling stand and a rolling piece variable describing the rolling stock,

- wherein the determined degree of wear includes in each case a relative movement-dependent wear degree component for a rolling stock section of the rolling stock.

The invention also relates to a computer program product comprising a machine code which can be directly processed by a computer and which is processed by the computer so that the computer implements the determination method.

The invention also relates to a computer which is designed in such a way that it carries out the determination method.

The invention also relates to a rolling mill comprising at least one rolling stand for rolling a rolling stock and which is equipped with such a computer.

Background technique

When rolling metal, wear occurs on the rolls. The extent to which wear occurs is related to various parameters. For example, the degree of wear depends on the type of rolls (work rolls, backup rolls, ...), the type of rolling (cold or hot), the layout of the rolls in the mill (first, second, third mill stand, etc.) or, in the case of reversing mills, depending on the pass number, the material of the rolled stock (steel, aluminium, copper, ...), the material of the rolls (cast iron, steel castings, high-speed steel, ...), etc.

Wear has an effect on the quality of the rolled stock. In particular, the degree of wear must be taken into account and compensated for as much as possible by means of corresponding positioning corrections (also with regard to shape and flatness in the case of flat rolled parts). In addition, the rolls must be replaced from time to time and regrinded.

Roll wear can only be measured directly if the rolls involved are disassembled from the mill stand and can be measured in their entirety. In contrast, it is not possible to directly measure roll wear during an ongoing rolling process. However, it is known to detect process variables of the rolling process and to take into account the degree of wear of the rolls in real time by means of a wear model. With the aid of the wear model, the degree of wear of the corresponding rolls is determined based on the rolling section of the rolling stock, the profile of the rolling force during this period, etc. The wear model provides other control systems with determined degrees of wear, for example to correct the positioning accordingly. It is also known to perform similar calculations offline. In this case, the process variables used can be, for example, expected variables determined with the aid of a model.

Recently, it has also been widely recognized that wear can have different wear components, in particular a thermal wear component and a relative motion-related wear component. The thermal wear component is essentially caused by intermittent heating of the roll during contact with the heat-generating stock and cooling of the roll between contact times. The relative motion-related wear component is due to the relative motion (leading and lagging) between the rolling stock and the roll. In particular, it causes rolling wear (abrasive wear component).

Various methods are known for modeling the thermal wear component. Purely illustrative citation of the specialist literature "Increasing work-roll life by improved roll-cooling practice" by P.G. Stevens et al., American Iron and Steel Institute Weekly, January 1971, Pages 1 to 11. In one of the inventor's earlier, published European patent application 10 174 341.7 (filing date 27 August 2010, titled "Determination of the degree of wear of rolls for rolling stock" which was not later than the filing date of the present invention A particularly good operating method for determining the thermal wear component is described in "Method").

The invention relates to the determination of the wear component associated with relative motion. Therefore, the determination and consideration of the thermal wear component will be discussed below only in the marginal region.

In the prior art it may have also been necessary to take into account the thermal crown of the roll when determining the position correction. Measuring and taking into account the thermal crown is also not the subject of the present invention.

The corresponding relative motion-related wear components are usually determined according to the following relationship:

dA＝c·Φ·α·l (1)

where dA represents the expected corresponding relative motion-related wear degree component, c represents the constant wear coefficient, Φ represents the pressure distribution in the roll gap, and α represents (substantially unique for the length of the contact area between the rolling stock and the roll ) contact angle, and l represents the length of the corresponding rolled piece section. Set the wear coefficient c appropriately. It can be related to the above parameters.

In practice, however, this method of operation does not adequately reflect actual relationships.

Contents of the invention

It is an object of the present invention to provide the possibility of using a model-assisted determination of the relative movement-related wear of a roll in a reliable manner.

This object is achieved by a method for determining the relative movement-related wear of rolls. It is contemplated according to the invention that an assay method of the type mentioned at the outset is devised in the following manner,

- Determination of a sliding zone for the section of the rolling stock in which the rolling stock is moving relative to the rolls, based on the process variable in combination with the rolling stand variable describing the first rolling stand and the rolling piece variable describing the rolling stock sliding on the roll surface without

Determination of the corresponding relative movement-related wear component taking into account the length of the corresponding sliding zone.

The invention is therefore based on the application of the known condition that during rolling there is a region (sticking zone) in which the rolling stock rests against the roll without moving relative to the roll (sticking) , while at the same time, the wear associated with the relative movement is due to the so-called grinding length, that is to say the length of the roll over which the relative movement between the roll and the workpiece occurs due to the superfastness and hysteresis of the workpiece. It is possible to create a model by means of which the sliding range can be determined directly. Alternatively, the (total) contact length and the (absolute or relative) length of the sticking area are determined, and the sliding area is then determined by means of the contact length and the sticking area. In particular, models are already known in the prior art which can also determine adhesion zones. Quoting purely by way of example the specialist literature "Effect of Sliding and Rolling Friction on the Energy-Force Parameters during Hot Rolling in Four-High Stands", By E.A. Garber et al., Metally, 2007, No. 6, pp. 484-491. This metal is also often used in the context of rolling chart calculations.

In the prior art, known models are used only for the determination of rolling force, rolling moment and lead. These models enable the determination of the variables while utilizing the flow characteristics of the stock, the coefficient of friction between the rolls and the stock, the desired pass reduction, the geometry of the stock, and the like. According to the invention, however, they can also be used for determining the adhesive zone and thus indirectly the sliding zone, whereby the relative movement-related wear can be determined by means of the sliding zone.

In a preferred refinement it is provided that the corresponding relative movement-related wear component is determined according to the following relationship,

dA=c·l·L·Z

where dA denotes the corresponding relative motion-related wear degree component, c denotes the adjustment factor independent of the process variable, l denotes the length of the corresponding rolling stock section, L denotes the length of the sliding zone, and Z denotes the process variable-dependent other effect variables. This method of operation allows the use of relatively simple wear models that have already provided good results.

In the simplest case it is possible for the other influencing variables to depend on the average pressure in the rolling gap (that is to say the quotient of rolling force and contact area). This approach often yields acceptable or even good results. However, better results can only be obtained when the other acting variables depend on the (exact) pressure distribution in the rolling gap. For example, the pressure distribution can be determined by means of the average flow stress or by means of the maximum flow curve (as a function of the degree of deformation).

Determining the pressure distribution in the rolling gap and constructing the adhesion zone (depending on the determination method) is computationally intensive. Therefore, it is preferably designed that

- Determining the pressure distribution in the rolling gap from the process variable in combination with the rolling stand variable and the rolling stock variable during the first acquisition of the process variable,

- storage of the measured pressure distribution,

- checking whether these process variables have changed against the process variables when they are later fetched, and

- Depending on whether the process variable has changed, it is decided whether to re-determine the pressure distribution in the rolling gap based on the new process variable in combination with the mill stand variable and the rolling stock variable, or to apply the pressure distribution stored in the rolling gap.

The real-time capability of the assay method according to the invention can be realized with relatively low computing power by means of this operating method.

As an alternative to the pressure distribution in the rolling nip, another active variable can be related to the surface hardness of the rolls. For example (corresponding to the method described in the earlier European patent application 10 174 341.7) it is possible to determine the relative movement-related wear component from the surface hardness and flow stress of the rolled stock. Alternatively, the relative movement-related wear component can be determined not only from the pressure distribution in the rolling gap but also from the surface hardness of the rolls, possibly with additional consideration of the flow stresses of the rolling stock. Other methods of operation are also possible.

If other acting variables are (also) dependent on the surface hardness of the roll, the upper limit temperature, to which the surface of the roll will heat up during contact with the roll, is preferably determined in real time from process variables combined with mill stand variables and stock variables . In this case, the determination of the surface hardness of the roll is preferably based on the determined upper limit temperature.

Preferably, the rolling gap lubricity is taken into account when determining the sliding zone.

It is possible to use the determined degree of wear in the context of determining the manipulated variable for the first rolling stand. Alternatively or additionally, it is possible to take the degree of wear into account for determining the roll change time. As long as the roll change point has been determined, the determination of the expected wear component can be linked to the wear prediction for the future. This kind of wear prediction is described in the applicant's earlier European patent application 10 174 297.1 (filing date 27 August 2010, which was not published in advance of the filing date of the present invention, titled "Application for Roll Wear Prediction" The operating method of a rolling mill for rolling flat stock") is described in detail.

Models for rolling mill processes often go wrong. They are therefore often adapted with the aid of acquired (measured) process variables. If adaptations are also to be made within the scope of the assay method according to the invention, various preferred operating methods can be used.

On the one hand it is possible to:

- process variables include the rolling force that occurs when rolling the rolled stock,

- detection of rolling force,

- determination of the expected rolling force using the flow curve of the rolling stock,

- determine the corresponding relative motion-related wear component directly or indirectly from the flow curve, and

-Follow the flow curve according to the detected rolling force and the expected rolling force.

On the other hand you can:

- the process variables include the rolling force that occurs when rolling the stock and the lead that occurs when rolling the stock,

- detection of rolling force and lead,

- determination of the expected rolling force and the expected lead using the flow curve of the rolling stock and the coefficient of friction of the rolling stock relative to the roll,

- determination of the corresponding relative motion-related wear component directly or indirectly from the flow curve and the coefficient of friction, and

-Track flow curve and coefficient of friction in terms of detected rolling force, expected rolling force, detected lead and expected lead.

Preferably, in the last-mentioned case above, the flow curve is not only tracked as a function of the rolling force. Furthermore, preferably, the coefficient of friction is not only tracked in terms of lead. Preferably, the flow curve is tracked, preferably not only as a function of the rolling force but also as a function of the advance. The same is preferably true for the coefficient of friction. In order to track the flow curve and the coefficient of friction, in particular a non-linear optimization procedure can be used. Many such suitable optimization programs are known. Purely exemplary reference to the specialist literature "Adaptive Rolling Model for a Cold Strip Tandem Mill" by Matthias Kurz et al. AISE 2001.

In order to detect the lead, a device is required by which the speed on the delivery side of the rolling stock can be accurately detected. For example, a ring elevator can be arranged behind the rolling stand, the rollers of which are positioned on the rolling stock. At a very good approach, the peripheral speed of the ring elevator corresponds to the speed of the output side of the rolling stock. In the case of using a thick plate reversing mill, it is also possible to use measurement technology to detect the length of the rolled piece before (after) rolling, and combine the duration of the roll hole and the time experienced by the roll during this period according to the detected length. The circular path measures the lead (lag).

The rolling forces can be detected in the individual rolling stands using appropriate measuring devices. However, it is possible that the gaining of the lead is carried out only in certain rolling stands. In this case, for example, not only the flow curve but also the coefficient of friction can be tracked in the roll stand (first roll stand) in which the lead is acquired in addition to the rolling force. In other rolling stands, in which only the rolling force is detected, but not the advance, (the second rolling stand) only the flow curve can be tracked as a function of the rolling force. However, it is possible to determine, from the coefficient of friction tracked for the first rolling stand, the use in the field of determining the degree of wear of the rolls of the second rolling stand in relation to the rolls of the rolling stock in relation to the second rolling stand coefficient of friction. In particular, the coefficient of friction of the first rolling stand can be received or calculated proportionally using a factor.

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

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

The object according to the invention is also achieved by a computer program product of the type mentioned at the outset. In this case, the computer program product is designed in such a way that the machine code is processed by a computer in such a way that the computer carries out the assay method with all the steps of the assay method according to the invention.

The object is also achieved by a computer which is designed in such a way that it carries out the determination method.

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

Description of drawings

In the following, the above-mentioned characteristics, features and advantages of the present invention, as well as the manner and method for realizing these characteristics, characteristics and advantages will be more clearly and comprehensibly set forth in conjunction with the description of the embodiments described in more detail with reference to the accompanying drawings. which shows:

Figure 1 schematically shows the rolling mill,

Figure 2 shows the flow chart,

Figure 3 schematically shows the rolling gap,

Figures 4 to 7 show flow charts,

Figure 8 schematically shows a rolling mill, and

9 and 10 show flowcharts.

Detailed ways

According to FIG. 1 , a rolling mill has a plurality of rolling stands 1 . Alternatively, the rolling mill can have only one rolling stand 1 , for example when using a reversing rolling mill. In the rolling stand 1 a rolling stock 2 is rolled. The rolling stock 2 is made of metal, for example copper, aluminium, brass or steel. In the rolling stand 1 , alternatively cold rolling or hot rolling can be carried out, wherein within the scope of the invention generally hot rolling is carried out.

According to FIG. 1 , rolling stand 1 has backup rolls 4 in addition to work rolls 3 . The rolling stock 2 is therefore a flat rolling stock, that is to say a strip or a thick steel plate. Alternatively, in particular for the rolling of uniquely contoured, rod-shaped or tubular rolling stock 2 , the back-up rolls 4 can be omitted, ie only the work rolls 3 are present.

The rolling mill is equipped with a computer 5 . According to the illustration in FIG. 1 , the computer 5 is able to control the rolling mill, ie 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 delivered to the computer 5 eg via a data carrier 7 on which the computer program 6 is stored in a machine-readable manner. The data carrier 7 is shown purely by way of example in FIG. 1 as a USB memory stick. However, this illustration is not to be understood in a restrictive manner.

The computer program 6 includes machine code 8 that can be directly processed by the computer 5 . Processing of the machine code 8 by the computer 5 causes the computer 5 to carry out an assay method which is explained in more detail below in conjunction with FIG. 2 . The computer program 6 is then programmed so that the computer 5 is configured accordingly.

According to FIG. 2 (see supplementary FIG. 1 ), the computer 5 sets the degree of wear d to an initial value in step S1 for a specific roll 3, 4 (for example the upper work roll 3 of the intermediate rolling stand 1 in FIG. 1 ) d0. For example, the computer 5 can be provided with the initial value d0 by the operator 9 or by other means. A further possibility of providing the initial value d0 consists, for example, in automatically transferring the initial value d0 from the grinding workshop of the rolls 3 , 4 involved in the fine grinding to the computer 5 .

In step S2, the control computer 5 knows the rolling stock variable W1, which describes the rolling stock 2 to be rolled. The rolling stock variable W1 includes, for example, the chemical composition, temperature and geometrical data of the rolling stock 2 . In particular the geometrical data and generally also the temperature are dependent on the state in which the rolling stock 2 enters the rolling stand 1 being observed. In the case of a flat rolling stock 2 , the geometrical data can include in particular the width and thickness of the rolling stock. The rolling stock variable W1 can be made known to the computer 5 in a manner similar to the initial value d0.

In step S3 , the computer 5 knows the rolling stand variable W2 which describes the rolling stand 1 and its rolls 3 , 4 . The stand variable W2 includes, for example, the installation position of the observed roll 3 , ie, for example, in the first, second, third etc. roll stand 1 of a multi-stand rolling mill. In addition, the mill stand variable W2 includes the material of the roll 3 (such as high-speed steel HSS), the type of the roll 3 (work roll, backup roll, intermediate roll, etc.) and the static geometric data (width and diameter) of the roll 3 being observed. ). The rolling stand data W2 can be made known to the computer 5 in a similar manner to the rolling stock data W1.

In a step S4 , the computer 5 acquires the process variable P during the rolling of the rolling stock 2 in the observed rolling stand 1 . The process variable P describes the rolling process in the observed rolling stand 1 . For example, these process variables 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 directly by means of a corresponding dynamometer. In a similar manner, the number of revolutions nW of the observed roll 3 can be detected by means of corresponding sensors, so that its peripheral speed can be derived immediately in conjunction with the (known) diameter of the observed roll 3 . Alternatively, the process variable p can be determined entirely or partly by calculation. For example, the lead can often only be determined by calculation. However, if the speed of the rolling stock 2 exiting the rolling stand 1 is detected using measuring technology, the lead can also be determined via the relationship of this speed to the observed peripheral speed of the roll 3 . In this case, it is also a measurement-based variable. For example, the speed of the rolling stock 2 exiting the rolling stand 1 can be detected via the number of revolutions nS of the endless elevator roller 10 positioned on the rolling stock 2 behind the observed rolling stand 1 . For example, due to the calculation of rolling diagrams, other process variables P can be known (eg positioning of rolling stand 1 , lubrication between roll 3 and rolling stock 2 ).

In step S5, the computer 5 measures the sliding zone 13 (see FIG. 3 ) and its length L through the rolling gap model 11 according to the process variable P combined with the rolling piece variable W1 and the rolling stand variable W2. The sliding zone 13 corresponds (see FIG. 3 ) to that area of the rolling gap in which the rolling stock 2 slides on the roll surface while moving relative to the roll 3 . Therefore, in the sliding zone 13, the rolling stock speed is either (specifically in the area on the entry side) less than the peripheral speed of the roll 3 or (in particular in the area on the output side) greater than the observed position. The peripheral speed of roll 3. The sliding zone 13 is in contrast to the sticking zone 14, in which the velocity of the rolling stock at the observed position is equal to the peripheral velocity of the roll 3 being observed. The sliding zone 13 and the adhesive zone 14 together form a contact region 15 of the roll 3 in which the roll 3 contacts the rolling stock 2 . The difference between the sliding zone 13 and the sticking zone 14 in FIG. 3 (purely in terms of drawing technique) is that the velocity of the rolling stock 2 in the sliding zone 13 on the entry side is indicated by a small arrow, and in the sliding zone 14 on the exit side The velocity in 13 is indicated by a large arrow, while the velocity of the rolling stock 2 in the adhesion zone 14 is indicated by an arrow of medium size. When determining the sliding area 13, the computer 5 preferably also takes into account the rolling gap smoothness.

There are various possibilities for determining the sliding area 13 . It is presently preferred to first measure the contact area 15 in a known manner (there is no distinction yet between the sliding zone 13 and the sticking zone 14), then measure the sticking zone 14 in a likewise known way and finally (according to the determination Whether the result of the sticking area 14 is an absolute value or a relative value) the sliding area 13 is determined according to the following relation:

Sliding area = contact area - sticky area or

Sliding area = contact area (1 - sticky area)

It may also be possible to also take into account the roll flattening effect when determining the sliding area 13 , the adhesive area 14 and/or the contact area 15 . In order to determine the contact area 15 and the adhesion area 14 , in particular the rolling gap model 11 can be used. A corresponding rolling gap model 11 is known. Reference is made purely schematically to the specialist literature mentioned at the outset by Garber et al.

In step S6, the computer 5 determines the wear component dA associated with the relative movement. In a step S6 , the computer 5 determines a relative movement-related wear component dA taking into account the sliding area 13 determined in step S5 . In particular the relative movement-related 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 thermal wear components dT. For the determination of the second wear component, the contact area 15 is usually also important. However, it is generally not necessary to distinguish between the sliding area 13 and the adhesive area 14 . In particular, the thermal wear component dT can be determined according to the method described in detail in the above-mentioned European patent application 10 174 341.7.

In step S8 , the computer 5 updates the degree of wear d by adding the relative movement-related wear degree component dA and possibly further wear degree components dT to the previously determined wear degree d.

In step S9, the computer 5 uses the measured degree of wear d. For example, if the computer 5 controls the rolling mill on the basis of the display in FIG. 1 , it can use the determined degree of wear d in the context of determining the manipulated variable S for the rolling mill stand 1 being observed. Alternatively or as a supplement, the computer 5 can compare the determined degree of wear d with the maximum allowable degree of wear and possibly issue an alarm to the operator 9 so that at a certain point in time (determined according to the degree of wear d) of the roll change The observed roll 3 must be replaced. Other methods are also possible.

In step S10, the computer 5 checks whether the rolling of the rolling stock 2 has ended. If not, the computer 5 returns to step S4 so that it re-executes steps S4 to S10.

As can be seen from the above embodiments, the computer 5 only calculates the relative motion-related wear degree component dA and may also calculate other wear degree components dT for one rolling piece section 16, and the rolling piece section is correspondingly experienced by During the cyclic operation of steps S4 to S10 , rolling is carried out in the rolling stand 1 under consideration. Therefore, the computer 5 determines in step S6 the relative motion-related wear component dA according to the following relationship, as described in step S6 of FIG. 2 ,

dA=c·l·L·Z

Here, c is an adjustment factor that is independent of the process variable P, l is the length of the corresponding rolling stock section 16 and Z is a further active variable that is dependent on the process variable P.

The determination of the other influencing variable Z can be carried out in various ways. A possible operating method for determining the other influencing variable Z is explained below in conjunction with FIG. 4 .

According to Fig. 4, in step S21, the computer 5 is based on the process variable P, the rolling piece variable W1 and the rolling stand variable W2, such as the temperature and chemical composition of the rolling piece 2, combined with the geometric shape of the rolling piece 2 and the desired pass The reduction is used to determine the pressure distribution in the rolling gap. The rolling gap model 11 can also be used for this purpose. Methods for designing such rolling gap models 11 are known to those skilled in the art.

In step S22, the computer 5 measures the upper limit temperature of the observed roll 3 according to the process variable P, the rolling piece variable W1 and the rolling stand variable W2, such as the roll diameter, the number of roll revolutions, the rolling piece geometry and the rolling piece temperature . This upper limit temperature is (at least substantially) equal to the temperature to which the surface of the roll 3 under observation rises during contact with the rolling stock 2 . Corresponding roll models are known to the skilled person. In step S23 , the computer 5 measures the observed surface hardness of the roll 3 according to the upper limit temperature of the roll 3 .

In step S24, the computer 5 determines another effect variable Z. For example computer 5 can measure another action variable Z according to the design scheme of step S24:

- according to the pressure distribution in the rolling gap, especially proportional to the pressure distribution in the rolling gap,

- depending on the observed surface hardness of the roll 3 , for example in such a way that the smaller the further variable Z is, the greater the surface hardness,

- depending on other process variables (especially rolling gap lubrication) or

- Determined according to a combined method of operation.

In step S6, the computer 5 determines the degree of wear dA associated with the relative movement according to the following relational expression:

dA=c·l·L·Z.

Determining the pressure distribution in the rolling gap is relatively computationally intensive. Therefore, the method according to FIG. 4 is preferably designed according to FIG. 5 .

According to FIG. 5 , after acquiring the process variables P, the computer checks in step S31 whether these process variables P have changed. If this is the case, the computer 5 determines the pressure distribution in the rolling gap in a step 21 and stores it in the memory 17 (see FIG. 1 ) in a step S32. If the process variable P has not changed, the computer 5 transitions from step S31 to a step S33 , in which the computer 5 reads the pressure distribution in the rolling gap from the memory 17 without performing a new determination.

When step S31 is executed for the first time, it must be ensured that the computer transitions to steps S21 and S32. This can be achieved, for example, in that the computer 5 sets the process variable P to an insignificant value during initialization (that is, before the first section 16 of the rolling stock 2 is rolled), for example by setting the rolling force FW to is the value 0.

If the determination of the relative movement-dependent wear degree component dA is carried out with the application of the flow stress of the rolling stock 2 , the coefficient of friction and/or the flow stress are preferably updated from time to time. If the coefficient of friction and/or the flow stress are updated outside of the determination method according to the invention—for example in the context of rolling force models or rolling diagram calculations—it is possible to receive these values respectively according to the invention in the measurement method. Alternatively, the determination method for determining the degree of wear d can be adapted. Figures 6 and 7 illustrate two preferred methods of operation.

According to Fig. 6, the computer 5 measures the pressure distribution in the rolling gap, the expected rolling force FW' and the expected Advance amount v'.

The process variable p usually also includes the rolling force FW and the lead v. The rolling force FW is usually obtained using measurement techniques. However, the rolling force FW, ie the actual rolling force, is not used within the scope of step S41. In the execution of step S41, the flow curve of the rolling stock 2 can alternatively be used, which not only participates in the determination of the pressure distribution, but also participates in the determination of the expected rolling force FW' and the expected advance v'. Since the relative motion-dependent wear component dA is related to the pressure distribution in the rolling gap, the relative motion-dependent wear component dA is determined from the flow curve. In this case, this association is an indirect natural property. Alternatively, there may be a direct relationship under certain conditions.

Thus, the computer 5 can compare the expected rolling force FW' determined by it with the actual rolling force FW in step S42 according to Fig. 6 . If there is (significant deviation), the computer 5 transitions to step S43. In step S43, the computer 5 tracks the flow curve based on the detected rolling force FW and the expected rolling force FW'.

FIG. 7 proceeds substantially from FIG. 6 . But steps S42 and S43 are replaced by steps S46 and S47.

In the refinement of FIG. 7 , it is assumed that, in addition to the rolling force FW, an advance v is provided as the actual measured variable, ie is captured. In contrast, the determination of the expected lead v' in step S41 is carried out without using the actual lead v. Alternatively, the expected lead v' is determined using the flow curve of the rolling stock 2 and the coefficient of friction relative to the observed roll 3 . As already described, the determination of the expected rolling force FW' is carried out while also utilizing the flow curve.

The coefficient of friction - like the flow curve - takes part in the determination of the degree of wear dA in relation to the relative movement. In particular the coefficient of friction is involved in the determination of the sliding zone 13 . Therefore, in step S46 - in addition to the rolling force FW and the expected rolling force FW' - the actual advance v and the expected advance v' are compared with each other. In the case of significant deviations, the computer 5 transitions to step S47. In step S47, the computer 5 tracks the flow curve and the friction coefficient according to the rolling force FW, the expected rolling force FW', the lead v and the expected lead v'. In particular, tracking can be carried out by means of a non-linear optimization program (not shown in the figure).

The operating methods according to FIGS. 6 and 7 can be combined with one another. In particular it is possible (see FIG. 8 ) to provide not only the rolling force FW but also the lead v as measured process variable P for certain rolling stands 1 of a multi-stand rolling mill, whereas for the rolling mill The other rolling stand 1 only provides the rolling force FW, but does not provide the lead v as a measured variable. According to FIG. 8 , for example, only the corresponding rolling force is captured in the front rolling stand 1 , while in the rear rolling stand 1 not only the corresponding rolling force FW is captured but also - via the ring elevator roller 10 and the coil Get the number of revolutions nS of machine 18, nH-get the corresponding advance amount v.

In order to be able to trace the coefficient of friction for a rolling stand 1 in which only the rolling force FW is detected, but not the advance v, the operating method according to FIGS. 6 and 7 can be modified, for example, according to FIGS. 9 and 10 . Wherein, FIG. 9 is a modification of FIG. 7, and FIG. 10 is a modification of FIG. 6.

According to FIG. 9 , for one of the rolling stands 1 for which an advance v is also detected as a measured variable, the traced friction coefficients are provided for the other rolling stands 1 in step S51 . According to FIG. 10 , in step S56 , the coefficient of friction provided by the rolling stand 1 in which no lead is detected is ascertained, and a suitable coefficient of friction is determined therefrom. For example, the coefficient of friction can be calculated proportionally in step S56 using a suitable factor.

According to FIG. 8 , the rolling stock 2 first passes through the rolling stand 1 in which only the rolling force FW is applied but not the advance v, and only later through the rolling stand in which both the rolling force FW and the advance v are obtained Seat 1. In particular, the front rolling stand 1 can be a roughing stand of a blooming mill, and the rear rolling stand 1 can be a finishing stand of a finishing mill.

The present invention has many advantages. In particular the operating method according to the invention enables a good and reliable prediction of the relative movement-related wear component dA. Furthermore, in particular in combination with the determination of the thermal wear component dT according to the principle of European patent application 10 174 341.7, it is possible to predetermine a unique wear model 12 which can be used for all of the multi-stand roll mills. Rolling mill stand 1. In this case, the wear model 12 can include the rolling gap model 11 as shown in FIG. 1 . Alternatively, the rolling gap model 11 can be placed outside the wear model 12, for example within the rolling diagram calculation device. Furthermore, a better sensitivity to process changes is possible, such as changes in the rolling gap lubrication or other changes in the coefficient of friction between the rolling stock 2 and the roll 3 being observed. It is also possible to better simulate the effect of rolling gap lubrication on wear degree d.

The invention is preferably used in the hot rolling of a flat rolling stock 2 . However, the invention can likewise also be used in the cold rolling of flat rolling stock 2 . The invention can also be used for hot rolling as well as cold rolling of other types of rolling stock 2 , for example rod-shaped rolling stock 2 or rolling stock 2 with unique shapes. Furthermore, it was not discussed above whether the relative movement-related wear component dA (and possibly also other wear components dT) determined in the width direction in the case of a flat rolling stock 2 is with spatial resolution or not. with spatial resolution. It goes without saying that both methods of operation are possible.

Although the invention has been illustrated and described in more detail by means of preferred embodiments, the invention is not restricted to the disclosed examples and other variants can be derived by a skilled person without departing from the scope of protection of the invention.

Claims (21)

1. a method for measuring the degree of wear (d) of the roll (3) of the first rolling mill stand for rolling a rolling stock (2), - wherein, during rolling of said rolling stock (2) in said first rolling stand, a process variable (P) describing the rolling process is acquired, - wherein said second mill stand variable (W2) describing said first mill stand (1) and a rolling stock variable (W1) describing said rolling stock are determined in real time from said process variable (P) said degree of wear (d) of said rolls (3) of a rolling mill stand, - wherein said measured degree of wear (d) comprises each a relative motion-related wear degree component (dA) for a rolling stock section (16) of said rolling stock (2), - wherein a sliding zone is determined from said process variable (P) in combination with said rolling stand variable (W2) describing said first rolling stand and said rolling piece variable (W1) describing said rolling stock and - wherein the respective relative motion-related wear component (dA) is determined taking into account the length (L) of the respective sliding zone ( 13 ). 2. The assay method according to claim 1, characterized in that, measure the corresponding relative motion related wear component (dA) according to the following relational expression, dA=c·l·L·Z Among them, dA represents the corresponding relative motion-related wear degree component, c represents the adjustment factor independent of the process variable (P), l represents the length of the corresponding rolling piece section (16), L represents The length of said sliding zone (13), and Z represents another effect variable related to said process variable (P). 3. The determination method according to claim 2, characterized in that the further effect variable (Z) is related to the pressure distribution in the rolling gap. 4. assay method according to claim 3, is characterized in that, - Determining the pressure in the rolling gap from said process variable (P) in combination with said mill stand variable (W2) and said rolling stock variable (W1) when said process variable (P) is acquired for the first time distributed, - storage of the measured pressure distribution, - checking whether said process variable (P) has changed according to said process variable (P) when said process variable (P) is acquired later, and - Depending on whether the process variable (P) has changed, the decision is to re-determine the rolling gap in the rolling gap according to the new process variable (P) in combination with the rolling stand variable (W2) and the rolling stock variable (W1) or the pressure distribution stored in the rolling gap. 5. Determination method according to claim 2, 3 or 4, characterized in that said further action variable (Z) is related to the surface hardness of said roll (3). 6. The assay method according to claim 5, characterized in that, according to the process variable (P) in conjunction with the rolling mill stand variable (W2) and the rolled piece variable (W1), measure the upper limit temperature in real time, the The surface of the roll (3) will heat up to the upper limit temperature during contact with the rolled piece (2), and the surface hardness of the roll (3) is determined according to the measured upper limit temperature. 7. The measuring method according to any one of claims 1 to 4, characterized in that the degree of rolling gap lubrication is taken into account when determining the sliding zone (13). 8. The measuring method according to claim 6, characterized in that the rolling gap lubricity is taken into account when measuring the sliding zone (13). 9. The measuring method according to any one of claims 1 to 4, characterized in that the determined degree of wear (d) is used in the context of determining the manipulated variable (S) for the first rolling stand , and/or take the degree of wear into account for determining the roll change time point. 10. The measuring method according to claim 8, characterized in that the determined degree of wear (d) is used in the context of determining the manipulated variable (S) for the first rolling stand, and/or the determined The degree of wear mentioned above is considered for determining the time point of roll replacement. 11. The assay method according to any one of claims 1 to 4, characterized in that, - said process variable (P) comprises the rolling force (FW) occurring when rolling said rolling stock (2), - detection of said rolling force (FW), - determination of the expected rolling force (FW') using the flow curve of said rolling stock (2), - determine the corresponding said relative motion-related wear component (dA) directly or indirectly from said flow curve, and - tracking said flow curve in terms of detected rolling force (FW) and expected rolling force (FW'). 12. assay method according to claim 10, is characterized in that, - said process variable (P) comprises the rolling force (FW) occurring when rolling said rolling stock (2), - detection of said rolling force (FW), - determination of the expected rolling force (FW') using the flow curve of said rolling stock (2), - determine the corresponding said relative motion-related wear component (dA) directly or indirectly from said flow curve, and - tracking said flow curve in terms of detected rolling force (FW) and expected rolling force (FW'). 13. The assay method according to any one of claims 1 to 4, characterized in that, - said process variables (P) comprise the rolling force (FW) occurring while rolling said rolling stock (2) and the lead (v) occurring while rolling said rolling stock (2), - detecting said rolling force (FW) and said lead (v), - Determining the expected rolling force (FW') and the expected lead using the flow curve of the rolling stock (2) and the coefficient of friction of the rolling stock (2) relative to the roll (3) volume (v'), - directly or indirectly determining the corresponding said relative motion-related wear component (dA) from said flow curve and said coefficient of friction, and - tracking of said flow curve in terms of said detected rolling force (FW), said expected rolling force (FW'), said detected lead (v) and said expected lead (v') and the coefficient of friction. 14. assay method according to claim 10, is characterized in that, - said process variables (P) comprise the rolling force (FW) occurring while rolling said rolling stock (2) and the lead (v) occurring while rolling said rolling stock (2), - detecting said rolling force (FW) and said lead (v), - Determining the expected rolling force (FW') and the expected lead using the flow curve of the rolling stock (2) and the coefficient of friction of the rolling stock (2) relative to the roll (3) volume (v'), - directly or indirectly determining the corresponding said relative motion-related wear component (dA) from said flow curve and said coefficient of friction, and - tracking of said flow curve in terms of said detected rolling force (FW), said expected rolling force (FW'), said detected lead (v) and said expected lead (v') and the coefficient of friction. 15. The measuring method according to claim 13, characterized in that the measuring method according to claim 11 is carried out for the rolls (3) of the second rolling stand, and according to the friction tracked for the first rolling stand The coefficient determines the degree of wear (d) of the roll (3) of the rolling stock (2) relative to the roll (3) of the second roll stand when determining the wear of the roll (3) of the second roll stand The coefficient of friction applied in the category of . 16. The measuring method according to claim 14, characterized in that the measuring method according to claim 9 is carried out for the rolls (3) of the second rolling stand, and according to the friction tracked for the first rolling stand The coefficient determines the degree of wear (d) of the roll (3) of the rolling stock (2) relative to the roll (3) of the second rolling stand when determining the wear of the roll (3) of the second rolling stand The coefficient of friction applied in the category of . 17. The measuring method according to claim 15, characterized in that the rolling stock (2) first passes through the second rolling stand and only then passes through the first rolling stand. 18. The measuring method according to claim 16, characterized in that the rolling stock (2) first passes through the second rolling stand and only then passes through the first rolling stand. 19. The measuring method according to claim 17, characterized in that the second rolling stand is a roughing stand of a blooming mill, and the first rolling stand is a finishing stand of a finishing mill. 20. The measuring method according to claim 18, characterized in that the second rolling stand is a roughing stand of a blooming mill, and the first rolling stand is a finishing stand of a finishing mill. 21. A method for performing an assay using a computer, characterized in that the method executes all the steps of the assay method according to any one of claims 1-20.