Title of Invention

A METHOD AND DEVICE FOR REDUCING THE EDGE DROP OF A ROLLED STRIP

Abstract

The invention relates to a method and device for reducing an edge drop of a rolled strip in a roll train having one or more roll stands, at least one roll stand having actuators for reducing the edge drop, which are set as a function of the edge drop of the rolled strip running out of the roll stand and, if appropriate, of the edge drop of the rolled strip running into the roll stand, the edge drop being measured with at least one edge drop measuring device, and the values of the edge drop of the rolled strip being determined using a roll gap model, in order to set the actuators for reducing the edge drop at those points on the rolled strip at which the edge drop is not measured.

Full Text

-1A- Description The invention relates to a method and device for reducing the edge drop of a rolled strip in a roll train. During the rolling of metal strips because of the mechanical properties of roll stands and the flow properties of the rolled metal, so-called edge drop occurs, that is to say a flattening of the rolled strip at the edges. It is known to counteract the edge drop by means of so-called tapered rolls. To this end/ the operating rolls are curved in a suitable way. In order to drive the so-called tapered rolls, the edge drop is measured upstream and downstream of the appropriate roll stand. However, these measurements are expensive, in particular when they have to be carried out for a plurality of roll stands. A further problem in the known method for reducing the edge drop is that the measures for reducing the edge drop must not lead to an impermissibly high tension in the edge region of the rolled strip nor to wavy edges. If the permissible tension in the edge region of the rolled strip is exceeded, then this can lead to an impermissible reduction in the quality of the rolled strip. In order to avoid this, in the case of the known method for reducing the edge drop, it is necessary to measure the strip tension in the edge region of the rolled strip. It is the object of the invention to specify a method and equipment for circumventing the abovementioned disadvantages. This object is achieved by means of a method and equipment according to the figures of the invention measuring equipment for measuring-the edge drop is saved. Furthermore, using the roll gap model it is possible to calculate the tension relationships in the roll strip, so - 2 - that: a complicated measurement of the tension relationships for monitoring can be dispensed with. In addition, the method according to the invention can advantageously be combined with flatness regulation or flatness control. The roll gap model moreover permits the edge drop to be calculated in advance, so that if appropriate necessary presettings can be made. Advantageous and inventive details emerge from the following description of exemplary embodiments, with reference to the accompanying drawings and in conjunction with the subclaims. In detail: FIG 1 shows the cross-section of a rolled strip, FIG 2 shows the inventive method for reducing the edge drop of a rolled strip, FIG 3 shows the inventive method for reducing the edge drop of a rolled strip in an alternative configuration, FIG 4 shows a model according to the inventive method for reducing the edge drop of a rolled strip, FIG 5 shows part of a device for reducing the edge drop of a rolled strip. FIG 1 shows the cross-section of a rolled strip with edge drop. In this case, b designates the width of the rolled strip, bx the region of the rolled strip which is free of edge drop and bG,L and bG,R the edge region of the rolled strip having edge drop. Furthermore, d5 designates the thickness of the rolled strip at a distance of 5 mm from the edge of the rolled strip, and d100 the thickness of the rolled strip at a distance of 100 mm from the edge of the rolled strip. These two values are included in one possible definition for the edge drop F, if this is expressed by a numerical value. This possible definition is: However, the edge drop can also be represented as a contour, that is to say as a function over the strip width. This representation advantageously forms the basis - 3 - of the inventive method for reducing the edge drop of a rolled strip. FIG 2 shows an exemplary application of the inventive method for reducing the edge drop of a rolled strip 11. The rolled strip 11 is rolled by means of five roll stands, a first roll stand indicated by the rolls 1 and 2, a second roll stand indicated by the rolls 3 and 4, a third roll stand indicated by the rolls 5 and 6, a fourth roll stand indicated by the rolls 7 and 8 and a fifth roll stand indicated by the rolls 9 and 10. The five roll stands are part of a five-stand or multi-stand roll train. The first, second and third roll stand have actuators 12, 13, 14, with which the edge drop of the rolled strip 11 can be influenced. Input variables for the actuators 12, 13 and 14 are the values for the edge drop P1, P2 and P3. Since the system has only two items of measuring equipment 21 and 22 for measuring the edge drop upstream of the first and downstream of the fifth roll stand, the edge drops downstream of the first roll stand P1, downstream of the second roll stand P2 and downstream of the third roll stand P3 are determined by means of a roll gap model. This model has five partial models 15, 16, 17, 18, 19, which are each assigned to one roll stand. Partial model 15 is assigned to the first roll stand, partial model 16 to the second roll stand, partial model 17 to the third roll stand, partial model 18 to the fourth roll stand and partial model 19 to the fifth roll stand. Output variables of the partial model 15 are the edge drop P1 and the tension relationships s1 in or downstream of the first roll stand, which are in turn input variables of the partial model 16. Output variables of the partial model 16 are the edge drop P3 and the tension relationships G2 in or downstream of the second roll stand, which are in turn input variables of the partial model 17. Output variables of the partial model 17 are the edge drop P3 and the tension relationships s3 in or downstream of the third roll stand, which are in turn input variables of the partial model 18. Output variables of the partial model 18 are the edge drop P4 - 4 - and the tension relationships s4 in or downstream of the fourth roll stand, which are in turn input variables of the partial model 19. Output variables of the partial model 19 are the edge drop F5 and the tension relationships C5 in or downstream of the fifth roll stand. The tension relationships s1, s2, s3, sA and s5 are to be understood as the web tension (flatness) and/or the tension of the rolled strip directly before entering the roll gap or directly after exiting from the roll gap. Input variables of the first partial model 15 are the edge-drop Po upstream of the first roll stand and, if appropriate, the tension relationships so upstream of the first roll stand. The tension relationships so upstream of the first roll stand are then included in the partial model 15 when the rolled strip is, for example, uncoiled from a coil. Further input variables of the partial models 15, 16, 17, 18, 19 are the roll contours for the individual roll stands. These input variables are not shown in FIG 1. The roll contour is advantageously calculated in a roll contour model which, inter alia, comprises a temperature model, a wear model and a bending model. In this case there is advantageously an individual roll contour model for each roll stand. During the rolling of the rolled strip 11, the partial models 15, 16, 17, 18, 19 are continuously adapted to the actual relationships in the roll stands by means of an adaptation 20, which determines appropriate parameters (1 (2, (3, (4 and (5 for the corresponding partial models 15, 16, 17, 18, 19 from the edge drop upstream of the first roll stand P0,1st from the edge drop P5 determined by the partial model 19 downstream of the fifth roll stand, and from the actual value of the edge drop P5,1st downstream of the fifth roll stand. FIG 3 shows an exemplary application of the inventive method for reducing the edge drop of a rolled strip 11. The rolled strip 11 is rolled by means of five roll stands, a first roll stand indicated by the rolls 1 and 2, a second roll stand indicated by the rolls 3 and 4, a third roll stand indicated by the rolls 5 and 6, a - 5 - fourth roll stand indicated by the rolls 7 and 8 and a fifth roll stand indicated by the rolls 9 and 10. The five roll stands are part of a five-stand or multi-stand roll train. The first, second and third roll stands have actuators 30, 31, 32 with which the edge drop of the rolled strip 11 can be influenced. Input variables of the actuators 30, 31 and 32 are the values for the edge drop P1 ,P2 and P3,1st. Since the system has only two items of measuring euipment 40 and 41 for measuring the edge drop upstream of the first and downstream of the third roll stand, the edge drops downstream of the first roll stand P1, downstream of the second roll stand F2 and downstream of the third roll stand P3 are determined by means of a roll gap model. This model has three partial models 33, 34 and 35, each of which is assigned to one roll stand. Partial model 33 is assigned to the first roll stand, partial model 34 to the second roll stand and partial model 35 to the third roll stand. Output variables of the partial model 33 are the edge drop P1 and the tension relationships s1 in or downstream of the first roll stand, which are in turn input variables of the partial model 34. Output variables of the partial model 34 are the edge drop P2 and the tension relationships s2 in or downstream of the second roll stand, which are in turn input variables of the partial model 35. Output variables of the partial model 35 are the edge drop P3 and, if appropriate, the tension relationships s3 in or downstream of the third roll stand. Input variables of the first partial model 33 are the edge drop PO,1st upstream of the first roll stand and, if appropriate, the tension relationships so upstream of the first roll stand. The tension relationships s0 upstream of the first roll stand are then included in the partial model 35 when the rolled strip is, for example, uncoiled from a coil. Further input variables of the partial models 33, 34 and 35 are the roll contours for the individual roll stands. These input variables are not shown in FIG 3. The roll contour is advantageously calculated in a roll contour model which, inter alia. - 6 - comprises a temperature model, a wear model and a bending model. In this case there is advantageously an individual roll contour model for each roll stand. During the rolling of the rolled strip 11, the partial models 33, 34 and 35 are continuously adapted to the actual relationships in the roll stands by means of an adaptation 36, which determines appropriate parameters (1, ( 2 and (3 for the corresponding partial models 33, 34 and 35 from the edge drop upstream of the first roll stand P0,1st from the edge drop P3 determined by the partial model 3 5 downstream of the third roll stand and the actual value of the edge drop P3,1st downstream of the third roll stand. FIG 4 illustrates the interaction of roll contour model 60, roll gap model 61 and an actuator 62. On the basis of process state information X1 and the output U1 of the actuator 62, the roll contour model 60 calculates the roll contour Wi, which is in turn an input variable into the roll gap model 61. Further input variables into the roll gap model are the edge drop Pi-1 and the tension relationships si-1 upstream of the roll stand. Output variables of the roll gap model 61 are the edge drop Pi and tension relationships si downstream of the roll stand. On the basis of the edge drop Pi downstream of the roll stand, the actuator 62 determines the manipulated variable Ui. FIG 5 shows a possible roll configuration for implementing the manipulated variable Ui from FIG 4. The steel strip 56 is rolled between two operating rolls 57 and 58. Supporting and intermediate rolls are not shown in FIG 5. In order to reduce the roll diameter at the end region of the rolled strip, which counteracts the edge drop, the system has two items of cooling equipment 54 and 55, from which coolant 50, 51, 52, 53, advantageously water, emerges and is applied to the operating rolls 54 and 58. The necessary coolant quantity corresponds, for example, to the variable U1 of FIGS 1 to 4. 7 We Claim: 1. A method for reducing an edge drop of a rolled strip in a roll train the roll train comprising at least one roll stand, the method comprising the steps of: -controlling actuators of the at least one roll stand as a function of an edge drop of a rolled strip which exits the at least one roll stand, the actuators being controlled to reduce the edge drop; -measuring the edge drop using at least one edge drop measuring device; -determining the edge drop using a roll gap model to set the actuators at particular points of the rolled strip, the particular points being points at which the edge drop is not measured; characterised in that when the rolled strip is rolled in the roll train, adapting the roll gap model to appropriate parameters of one of the at least one roll stand and the rolled strip, the actual relationship being continuously determined by an adaptation; and in that measuring the edge drop at n number of predetermined points on the rolled strip, wherein the n number is less than or equal to a number of roll stands having actuators. 2, The method as claimed in claim 1, wherein the controlling step comprises setting the actuators as a function of a particular edge drop of a particular rolled strip which enters into the at least one roll stand. 8 3. The method as claimed in claim 1, comprising the step of : using the roll gap model, determining the edge drop as a function of a particular edge drop which is determined from a particular roll stand of the at least one roll stand which is positioned upstream of one of the roll stand and preceding roll stands of the at least one roll stand. 4. The method as claimed in claim 3, comprising the step of: using the roll gap model, determining the edge drop as a function of one of: (a) the particular edge drop, (b) tension relationships of the particular rolled stnp,and (c) a roll contour of the particular roll stand, 5. The method as claimed in claim 1, comprising the step of : measuring the edge drop at two points of the rolled strip. 6. The method as claimed in claim 5, comprising the step of : measuring the edge drop upstream of a first stand of the at least one stand and downstream of a last stand of the at least one stand. 7. The method as claimed in claim 5, comprising the steps of : with the at least one roll stand, reducing the edge drop in particular upstream roll stands of the at least one roll stand in the roll train; 9 measuring an edge drop upstream of a first stand of the at least one stand; and measuring an edge drop downstream of a last stand of the at least one stand. 8. The method as claimed in claim 3, comprising the step of : determining a roll contour in a roll contour model. 9. The method as claimed in claim 8, wherein a roll contour model comprises a bending model, a temperature model and a wear model. 10.The method as claimed in claim 1, wherein a roll gap model is assigned to each roll stand. 11.The method as claimed in claim 1, comprising the step of: assigning a plurality of stands with the roll gap model. 12.The method as claimed in claim 11, wherein the at least one roll stand comprises a plurality of roll stands, and the method further comprising the step of: modeling all of the roll stands using the roll gap model. 13. A method for reducing an edge drop of a rolled strip in a roll train as claimed in claim 1, the roll train comprising at least one roll stand, the method comprising the steps of : 10 controlling actuators of the at least one roll stand as a function of an edge drop of a rolled strip which exits the at least one roll stand, the actuators being controlled to reduce the edge drop; measuring the edge drop using at least one edge drop measuring device; determining values of the edge drop using a roll gap model to set the actuators at particular points of the rolled strip, the particular points being points at which the edge drop is not measured; monitoring a tensile stress of the rolled strip; determining at least one tensile relationship of the rolled strip using the roll gap model; and if a value of the at least one tension relationship is greater than a predetermined value, limiting a reduction of the edge drop. 14.The method as claimed in claim 13, wherein the controlling step, comprises setting the actuators as a function of a particular edge drop of a particular rolled strip which enters into the at least one roll stand. 15.The method as claimed in claim 13, comprising the step of : using the roll gap model, determining the edge drop as a function of a particular edge drop which is determined from a particular roll stand of the at least one roll stand which is positioned upstream of one of the roll stand and preceding roll stands of the at least one roll stand. 11 16.The method as claimed in claim 15, comprising the step of: using the roll gap model, determining the further edge drop as a function of one of: (a) the particular edge drop, (b) tension relationships of the particular rolled strip, and (c) a roll contour of the particular roll stand. 17.The method as claimed in claim 13, comprising the step of : measuring the edge drop at two points of the rolled strip. 18.The method as claimed in claim 13, comprising the step of : measuring the edge drop upstream of a first stand of the at least one stand and downstream of a last stand of the at least one stand. 19.The method as claimed in claim 13, comprising the steps of : with the at least one roll stand, reducing the edge drop in particular upstream roll stands of the at least one roll stand in the roll train ; measuring an edge drop upstream of a stand of the at least one stand; and measuring an edge drop downstream of a last stand of the at least one stand. 12 20.The method as claimed in claim 15, comprising the step of: determining a roll contour in a roll contour model. 21.The method as claimed in claim 20, wherein a roll contour model comprises a bending model, a temperature model and a wear model. 22.The method as claimed in claim 13, wherein a roll gap model is assigned to each roll stand. 23.The method as claimed in claim 13, comprising the step of : modeling a plurality of stands with the roll gap model. 24.The method as claimed in claim 23, wherein the at least one roll stand composes a plurality of roll stands, and the method comprising the step of: modeling all of the roll stands using the roll gap model. 25. An arrangement for reducing an edge drop of a rolled strip in a roll train, the roll train having at least one roll stand for rolling the rolled strip, the arrangement comprising: - at least one edge drop measuring means measuring the edge drop; and - means reducing the edge drop by determining the edge drop, Characterized in that : - the means, using a roll gap model, controls actuators of the at least one roll stand to reduce the edge drop at particular points of the rolled strip at which the edge drop is not measured, - the actuators are controlled as a function of a particular edge drop of a particular rolled strip exiting the at least one roll stand, - when the rolled strip is rolled in the roll train, the roll gap model is adapted to instantaneously applicable parameters of one of the at least one roll stand and the rolled strip, and - the edge drop is measured at an number of predetermined points of the rolled strip, the number being less than a number of the at least one roll stand. 26.The arrangement is claimed in claim 25, wherein the actuators are controlled as a function of an edge drop of a second rolled strip which enters the at least one roll stand. 27. An arrangement as claimed in claim 25, for reducing an edge drop of a rolled strip in a roll train, the roll train having at least one roll stand for rolling the rolled strip, the device comprising: -at least one edge drop measuring means measuring the edge drop; and -means reducing the edge drop by determining the edge drop, characterized in that 14 - the means, using a roll gap model, controls actuators of the at least one roll stand to reduce the edge drop at particular points of the rolled strip at which the edge drop is not measured, - the actuators are controlled as a function of a particular edge drop of a particular rolled strip exiting the at least one roll stand, wherein a tensile stress of the rolled strip is monitored, and - if values of tension relationships of the rolled strip exceed a predetermined value, the actuators limit a reduction in the edge drop, the tensile relationships being determined with the roll gap model. 28.The device as claimed in claim 27, wherein the actuators are additionally set as a function of an edge drop of a second rolled strip which enters into the at least one roll stand. Dated this 10th Day of June, 1997. OF L . S . DAVAR & CO. APPLICANTS' AGENT The invention relates to a method and device for reducing an edge drop of a rolled strip in a roll train having one or more roll stands, at least one roll stand having actuators for reducing the edge drop, which are set as a function of the edge drop of the rolled strip running out of the roll stand and, if appropriate, of the edge drop of the rolled strip running into the roll stand, the edge drop being measured with at least one edge drop measuring device, and the values of the edge drop of the rolled strip being determined using a roll gap model, in order to set the actuators for reducing the edge drop at those points on the rolled strip at which the edge drop is not measured.

Documents:

01093-cal-1997 abstract.pdf

01093-cal-1997 claims.pdf

01093-cal-1997 correspondence.pdf

01093-cal-1997 description(complete).pdf

01093-cal-1997 drawings.pdf

01093-cal-1997 form-1.pdf

01093-cal-1997 form-2.pdf

01093-cal-1997 form-3.pdf

01093-cal-1997 form-5.pdf

01093-cal-1997 g.p.a.pdf

01093-cal-1997 priority document.pdf

1093-CAL-1997-(03-10-2012)-FORM-27.pdf

1093-CAL-1997-CORRESPONDENCE.pdf

1093-CAL-1997-FORM-27.pdf

1093-cal-1997-granted-abstract.pdf

1093-cal-1997-granted-claims.pdf

1093-cal-1997-granted-correspondence.pdf

1093-cal-1997-granted-description (complete).pdf

1093-cal-1997-granted-drawings.pdf

1093-cal-1997-granted-examination report.pdf

1093-cal-1997-granted-form 1.pdf

1093-cal-1997-granted-form 2.pdf

1093-cal-1997-granted-form 3.pdf

1093-cal-1997-granted-form 5.pdf

1093-cal-1997-granted-gpa.pdf

1093-cal-1997-granted-letter patent.pdf

1093-cal-1997-granted-priority document.pdf

1093-cal-1997-granted-reply to examination report.pdf

1093-cal-1997-granted-specification.pdf

1093-cal-1997-granted-translated copy of priority document.pdf

1093-CAL-1997-PA.pdf