MXPA98008402A - Device and procedure for influence of the conditions of friction between a upper cylinder and a lower cylinder of a box of laminac - Google Patents

Abstract

The present invention relates to an apparatus for influencing the friction conditions between a strip strip and an upper cylinder and a lower cylinder of a rolling box of a hot rolling mill for a strip or broad band or a train of cold rolling for strip strips, the apparatus comprises a spraying device disposed on an inlet side of the roll stand for spraying a quantity of liquid, on each upper side of the strip or strip and the underside of the strip or band and a control device for determining the amount sprayed on the upper side and the amount of liquid sprayed on the lower side is in dependence on the actual torque or torque of the cylinder, of at least one of the lower cylinder and the upper cylinder.

Description

Device and procedure for influencing the friction conditions between an upper cylinder and a lower cylinder of a rolling stand FIELD OF THE INVENTION The invention relates to a device for influencing the conditions of friction between an upper cylinder and a lower cylinder of a rolling box of a hot-rolled broadband mill or a cold-rolled rolling mill. as well as to a method for rolling a rolled product under the influence of the friction conditions between an upper cylinder and a lower cylinder of a rolling stand. DESCRIPTION OF THE PREVIOUS TECHNIQUE In practice it has been shown that the torque between the upper cylinder and the lower cylinder of a rolling box of a hot-rolled broadband mill or a cold-rolled mill train oscillates very sharply during the rolling process. The torque differences between the upper cylinder and the lower cylinder of the order of magnitude between 30 and 70% are not uncommon. The reasons for this are the different friction conditions in the inter-cylinder, on the one hand between the upper cylinder and the upper side of the strip of the rolled product and on the other hand between the lower cylinder and the lower side of the strip of the rolled product. Starting from this, these friction conditions give rise to a different torque demand in the upper and lower cylinders. In addition to this, on these different friction conditions, the so-called bonding angle of the hot or cold strip around the upper cylinder and the lower cylinder, caused by the loop elevator or reversing pulley, has an influence. The different friction conditions in the inter-cylinder, the unequal distribution of the torque demand of the upper cylinder and the lower cylinder caused by these not only influence the design of the participating components, such as, for example, drive spindles, gears etc., but also represent a reduction in both the surface quality of the belt and the duration of application of the cylinders between two cylinder changes as well as their useful life due to high wear. Due to the different friction conditions, it is also not possible to carry out uniformly distributed decreases of the hot or cold strip between the upper cylinders and the lower cylinders. As the resistance of the laminated product against deformation is composed of the resistance to deformation of the material itself and a resistance to the flow between the cylinders and the rolled product, for a lower resistance to creep more material is formed than for a resistance greater than creep, which means that the decrease or elongation of the rolled product is greater in the part of the rolling mill, which has the lowest coefficient of friction, and with it, the resistance to the lowest creep of the rolled product. This leads to the laminated product having different qualities on its length and, therefore, often not being adapted to the quality requirements. To the decrease per pass is tied a stretch that means that the rolled product is prolonged. In the entrance area of the rolling stand the rolled product reaches the two cylinders, both on the upper side and also on the lower side of the strip, with the same speed of entry. As a consequence, the rolled product is forced out of the cylinders with the same speed both on the upper side and also on the lower side of the belt. But this presupposes that the guide coefficients both between the upper cylinder and the upper side of the belt as well as the coefficients of friction between the lower cylinder of the lower side of the belt are of equal magnitude. But as already described, in the practical operation appear different coefficients of friction, with the consequence that the rolled product slides between the cylinders. This additional relative movement between the cylinders and the rolled product due to the different friction conditions can be recognized in the wear graph of the outer surface of the cylinders. It can also be seen in the curving upwards or downwards of the beginning of the strip, that is, in the rolled product directed upwards or downwards after the exit of the rolling stand. In any case, in addition to the creep of the rolled product during forming, these relative movements appear that negatively influence the performance of the rolling process and thereby not only increase the energy consumption and increase the wear of the cylinders, but also affect greatly measure the surface quality of the band. The invention is based on the objective of creating a device that allows both the upper side of the strip of the rolled product and the upper cylinder as well as between the lower side of the strip of the rolled product and the lower cylinder, almost equal friction to improve the performance of the rolling process as well as to reduce the wear of the upper and lower cylinders and also dampen the tendency to vibrations that frequently occur in large reductions in thickness. This objective is achieved by a device consisting of a spray device arranged on the inlet side of the roll stand, for spraying a defined flow rate of liquid in the direction of the inter-roll, and of a regulating device for the determining and emitting the flow rate of this liquid, with a predetermined amount being provided as a control variable or also calculated in combination with the actual rolling torque of the lower cylinder and / or the upper cylinder. In addition, the invention, for achieving the objective, provides a method for rolling the laminated product by influencing the friction conditions between an upper cylinder and a lower cylinder of the rolling stand, whereby the upper side of the band and / or the lower side of the strip of the rolled product on the inlet side of the rolling stand is moistened with a defined flow rate of liquid by means of a spraying device and a regulating device regulates the flow rate determination and the emission of liquid, a predetermined amount being provided as a control variable or also calculated in combination with the actual rolling torque of the lower cylinder and / or the upper cylinder. For this purpose, as the spraying device, an upper spray tube and a lower spray tube are preferably arranged on the inlet side of the box in the vicinity of the cylinder in the area of the upper cylinder and the lower cylinder, respectively. The spray tubes themselves preferably have nozzles uniformly distributed or, for example, in a parabolic shape, whose direction of projection directly reaches the intercylinder. The matching of the friction conditions between the upper cylinder and the lower cylinder with respect to the laminated product is achieved by the variation of the liquid flow rate, preferably water or a water-oil mixture, which is injected in the zone of the inter-cylinder. The flow of liquid, which is injected in the direction of the cylinder, is determined by a regulation device. This regulating device is also provided for regulating the action of the two spray tubes independently of one another, that is, for example, in such a way that less liquid is fed to the upper spray tube and to the lower spray tube more liquid. This regulating device further comprises measuring value sensors that determine in particular the torque actually produced in the upper and lower cylinders of the rolling stand. The torque difference that is calculated starting from the registered torque values is proportional to the flow of liquid emitted. This flow of liquid, it must also be established for this reason with such a magnitude that, on the one hand, there is not a high impermissible cooling of both the upper surface and the lower surface of the band, and that, on the other hand, a range of regulation sufficient for the equalization of the friction conditions in the inter-cylinder. The torque recording is preferably carried out by means of measuring value transmitters arranged in the cylinders drive spindles. For the operation of the cylinders with separate drives for the upper cylinder and for the lower cylinder, there is an additional arrangement of separate measurement value transmitters of this type, since reference to the regulation can be taken here as the consumption of current of the drive motors because this remains proportional to the actual torque. The regulating device further comprises regulating valves that adjust in correspondence with the predetermined or calculated torque value. Preferably two valves are provided, the first valve being provided for the quantitative emission of water and the second regulating valve for the quantitative emission of oil. Depending on the position of the regulating valves, a different proportion of the water-oil mixture results, a different effect on the cylinders and thus different variations of the coefficients of friction between the upper part of the belt and the upper cylinder and between the lower part of the band and the lower cylinder. The sign of the corresponding torque difference or the deviation of a defined theoretical torque difference represents the signal for the direction in which the valve has to be adjusted.

It is also possible to use only valve as regulation valve. The other regulating valve is set for this in a defined base position which is approximately in the middle of the area of the control range available for the valve that can be adjusted in both directions, which suffices for the rolling program. The position of this valve can be adapted to any rolling program. But it is also possible that the valves for the upper spray tube and the lower spray tube are regulated from a base position in opposite directions to take advantage of the maximum possible field of regulation. The invention also provides that the composition of the water-oil mixture for the lubrication of the inter-cylinder is included in the regulation. In the same way that the difference of the corresponding torque in the cylinders drive spindles for the regulation of one of the two valves for the spray pipes is taken as reference, the sum of the pairs in the spindles, through which minimum are used as a signal for the optimization of the composition of the water-oil mixture. Other configurations of the invention emerge from the subordinate claims. The invention is explained in more detail with the aid of the exemplary embodiments shown in the drawing. BRIEF DESCRIPTION OF THE DRAWINGS In the drawing show: Fig. 1 a diagram of connections for the regulation of the device in schematic representation and Fig. 2 the view of the device in schematic representation in perspective together with the regulation device, also in representation schematic DETAILED DESCRIPTION OF THE INVENTION The device 1, as shown in Fig. 2, consists of a spraying device 2 and a regulating device 3 coupled with it. The spraying device 2 comprises, arranged in the zones 4 and 5 corresponding to the upper and lower cylinder 6 and 7, spray tubes 8, 9 mounted parallel to the axes of the cylinders, which have nozzles 10 on their periphery that are arranged in such a way that a jet of water or water-oil mixture conducted through the tubes is guided through the nozzles 10 in the direction of the arrow 11 towards the cylinder 12. The spray tubes 8, 9 are connected to a pipe system 13. In the exemplary embodiment (see FIG. 1), two pipes lead to each pipe 13a, of which a first pipe 13a7 is provided for water pipes and a second pipe 13a The two lines 13a 'and 13a' 'are arranged in front of the inlet in the spray pipes 8, 9 and thus make available the water-oil mixture provided for the reduction of the oil flow. rozam coefficient Each of the two conduits 13a7 and 13a77 has regulating valves 14, 15 and 16, 17, respectively, which are connected to the regulator 18 of the regulating device 3. The regulator 3 processes the information that arrives through the regulator 3. the transmitters of measurement values 19, 20 (other transmitters of measured value are indicated in broken lines). These transmitters of measured values are, for example, arranged in the drive spindle 21 (FIG. 2) for the measurement of the current torque. The regulator 3 correspondingly controls the regulating valves 14, 15, 16, 16, 17 in such a way that a calibrated flow of liquid arrives in the region of the cylinder 12 and thereby ensures that equal friction conditions are achieved between yes between the upper side 23 of the band 25 and the upper cylinder 6, as well as between the lower side 24 of the band 25 and the lower cylinder 7. The upper and lower cylinders 7, 8 are driven as shown in Fig. .2 through the spindles 21, 22 of the main drive. With separate drive of the upper and lower cylinders 6, 7 are eliminated Measuring devices in the spindles of the main drive, since for the purposes of regulation, the current consumption of each of the drive motors is measured. In one embodiment not shown in the drawing, a regulating valve is controlled by the regulator while the position of the other regulating valve is adapted to the corresponding rolling program by a subordinate computer system. In this case it is also conceivable that the regulator pumps the other regulating valve and the computer system subordinates the first regulating valve. But since as a rule the consumption of liquid for the lower cylinder is always greater than that of the upper cylinder because on the upper side of the belt also accumulates liquid that comes from the cooling device of the cylinders for the upper cylinder and this arrives to drip laterally on the scrapers on the surface the surface of the beltWhen the other valve is regulated, too much water reaches the surface of the band. The other valve would then be adjusted for compensation so that the action of sufficient liquid on the upper side of the band would be compensated by the addition of more water on the lower side of the band. If the lower water flow rate is set fixed for the corresponding rolling program, the uncontrolled liquid flowing on the upper side of the band would be included in the regulation. In the cases of regulation of the two regulating valves in opposite directions, the base liquid flow is established in the center of the regulation field of the computer system. In some of the rolling programs, an additional advantageous action is also taken on the reduction of cylinder wear if a special rolling oil is mixed with the liquid to be injected into the cylinder. The correct mixing ratio in this is determined by experience. In this use of rolling oil, for variable injection flows it is convenient to keep the mixing ratio constant through the corresponding oil regulating valve.

Claims (21)

1. CLAIMS 1. Device (1) for influencing the friction conditions between an upper cylinder and a lower cylinder (6, 7) of a rolling stand (28) of a hot broadband train or a band train cold formed by a spray device (2) disposed on the inlet side (27) of a rolling box (28) for spraying a defined flow of liquid in the direction of the intercylinder and a regulating device (3) ) for the quantitative determination and emission of this liquid, a predetermined quantity or calculated in combination with the actual rolling torque of the lower cylinder or / and the upper cylinder being provided as the control variable. Device according to claim 1, characterized in that the liquid is water. Device according to one of claims 1 or 2, characterized in that the liquid is a water-oil mixture. Device according to claim 1, characterized by the rolling oil mixed additionally with the liquid. Device according to claim 1, characterized by lubricants with different frictional properties incorporated on the upper side and on the lower side of the belt. Device according to one of the preceding claims, characterized in that the spraying device (2) comprises at least one spray tube (8, 9) arranged in the region of the cylinders (4, 5). Device according to claim 6, characterized in that the spray tube (8, 9) has nozzles (10) which in the assembled state are directed to the cylinders (6, 7). Device according to claim 6, characterized in that the spray tube (8, 9) has nozzles (10) that in the mounted state of the spray device (2) are directed towards the entrecilindro (12). Device according to claim 6, characterized in that the spray tube (8, 9) has nozzles (10) that in the mounted state of the spray device (2) are directed towards the laminated product (25). Method for rolling laminate products in the form of strips due to the friction conditions between the upper and lower cylinders of a rolling stand, characterized in that the upper side of the strip (23) and / or the lower side of the strip (24) of the laminated product (25) is moistened on the inlet side (27) of the rolling stand by means of a spraying device (2) with a defined flow rate of liquid and a regulating device (3) regulates the quantitative determination and the emission of the liquid, a predetermined quantity or calculated in combination with the actual rolling torque of the lower cylinder and / or the upper cylinder being used as the control variable. 11. Method according to claim 10, characterized in that the difference in torque between the upper cylinder and the lower cylinder (6, 7) is used as the control variable. 12. Method according to claim 11 and / or 12, characterized in that the theoretical torque difference between the upper cylinder and the lower cylinder (6, 7) is = 0 or? 0. The method according to claim 11, characterized in that the torque difference is measured directly between the upper cylinder and the lower cylinder (6, 7). 14. The method according to claim 11, characterized in that in a rolling box with a twisted drive the rolling torque is measured by the drive current of the motor and the lower cylinder (6, 7). Method according to claim 10 or 11, characterized in that the control variable is determined as a function of the magnitude of the minimum required rolling torque. Method according to claim 10, 11 or 15, characterized in that the control variable is determined as a function of the difference in diameters of the upper cylinder and the lower cylinder (6, 7) of the rolling stand (28). 17. Method according to claim 10, 11, 15, 16 or 17, characterized in that the control variable is determined as a function of the rolling speed of the rolled product (25). Method according to claim 10, 11, 15 or 16, characterized in that the control variable is determined as a function of the strip thickness of the rolled product (25). 19. Method according to claims 10, 11, or 13 a 18, characterized in that the control variable is determined as a function of the rolling temperature. 20. Process according to claims 10, 11, or 13 a 19, characterized in that the control variable is determined as a function of the stretching tension and the yield strength of the rolled product (25). 21. The method according to one of the preceding claims, characterized in that the difference in diameter between the upper cylinder and the lower cylinder is increased to produce a rolling effect.