JP2008194733A - Cooling device and method for work roll of metal plate rolling mill, and metal plate manufacturing method using the same cooling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To favorably exercise a control, in which the cooling efficiency at the time of cooling work rolls 19 of a metal plate rolling mill M with cooling water w has a longitudinal distribution of the work roll, to secure flatness of a to-be-rolled material 8 after rolling, and to effectively prevent troubles in the to-be-rolled material 8 on rolling, such as pitting caused by the center buckle. <P>SOLUTION: The pressure of cooling water to be supplied on the surface of the work roll of the metal plate rolling mill is made higher at the longitudinal center zone of the work roll than at both outside zones. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a work roll cooling device for a metal plate rolling machine, a work roll cooling method for a metal plate rolling machine, and a metal plate manufacturing method using the work roll cooling method. The metal plate referred to in the present invention includes a metal band.

  Hereinafter, for the sake of simplicity, first, the case of hot rolling is taken as an example. Hot rolling is generally a slab-like metal material produced by continuous casting, ingot-making, or ingoting, heated in a heating furnace to several hundred to several hundreds of degrees Celsius, and then placed on a hot rolling line. It is a series of processes of extracting and winding thinly and winding it into a coil shape by rotating the roll while pinching with a pair or a plurality of pairs of rolls.

  FIG. 9 shows an example of a hot rolling line 100 generally used conventionally. A metal material 8 having a thickness of 150 to 300 mm (hereinafter referred to as a material to be rolled) heated to several hundred to several hundreds of degrees Celsius by the heating furnace 10 is rolled to a thickness of 0.8 to 25 mm by a roughing mill 12 and a finishing mill 18. And thinly stretched into a metal strip. Reference numeral 7 denotes a table roll, which conveys the material 8 to be rolled.

  In the case of the hot rolling line 100 shown in FIG. 9, the rough rolling mill 12 has three R1 to R3 units, but there are various types from one to six.

  In the case of the hot rolling line 100 shown in FIG. 9, the number of rolling mills (stands) constituting the finish rolling mill 18 is seven of F1 to F7, but there are six.

  Although there are differences in these various radixes, the rough rolling machine 12 generally performs a total of 6 times or 7 times of rolling by reciprocating rolling or unidirectional rolling, or both, and the material 8 to be rolled after rough rolling. Is fed to the finishing mill 18 that follows. Performing rolling 6 times or 7 times is also referred to as performing 6-pass or 7-pass rolling.

  The finishing mill 18 often takes the form of a tandem rolling mill that simultaneously rolls with a plurality of rolling mills. Although there is also a term called a finishing tandem rolling mill, it is often simply referred to as a “finishing mill” for short. 19 is a work roll, 19A is a backup roll, and 20 is a looper. Since each roll 19 and 19A is in contact with a hot material to be rolled, it is cooled with cooling water.

  By the way, when extracted from the heating furnace 10, an oxide layer (hereinafter referred to as scale) is formed on the front and back surfaces of the high-temperature rolled material 8 heated to several hundred to several hundreds of degrees Celsius as described above. is doing. In addition, since the rolled material 8 is exposed to the atmosphere at a high temperature even in the process of being rolled and thinned and lowered in temperature by heat radiation, new scales are generated on the front and back surfaces of the rolled material 8. For this reason, on the entry side of each rolling mill in the rough rolling mill 12, descaling is performed by spraying high-pressure water inside and outside 10 to 30 MPa on the front and back surfaces of the material to be rolled 8 as the supply pressure from the pump. A device 16 is installed to remove the scale.

  Reference numeral 14 denotes a crop shear, which cuts and removes the crop at the leading end of the material 8 to be rolled (finished portion of the leading end of the material 8 to be distorted) before finish rolling, and smoothly finishes it on the finishing mill 18. Shape into a substantially rectangular planar shape that is easy to bite.

  50 is a control device, 70 is a process computer, and 90 is a business computer.

  In the rough rolling mill 12 and the finish rolling mill 18, any one rolling mill is used to roll a material 8 having a very high temperature of 800 to 1200 ° C. Therefore, as shown in FIG. It is heated by heat input from the rolled material 8 and expands thermally.

  At this time, a portion (so-called outside of the plate path) B corresponding to the outside of the material to be rolled 8 of the work roll 19 is not in contact with the material to be rolled 8 and is at a relatively low temperature. Since the heat escapes from the region C ′ near the outside of the plate path B to the outside of the plate path B in the center region C in the cylinder length direction of the work roll 19 toward the outside of the plate path B, the cylinder of the work roll 19 The thermal expansion is large in a part of the central region in the long direction (CC ′), and the thermal expansion is small in the region of C ′ near the outside B of the plate length in the central region C of the body length of the work roll 19. A roll profile having a substantially trapezoidal shape is formed (hereinafter referred to as a thermal crown).

  The thickness and shape of the material 8 to be rolled after finish rolling are required to be uniform and flat in terms of quality, but the portion of the thermal crown D protruding in a substantially trapezoidal shape of the work roll 19 is: As shown in FIG. 10, as a result of being transferred to the material to be rolled 8 when the material to be rolled 8 is rolled by the work roll 19, the material to be rolled 8 is thin in the central region of the width, and at both width end portions. As the thickness of the material 8 increases, the thickness of the material 8 to be rolled after the finish rolling is unevenly distributed in the width direction. As shown in FIG. It becomes an aspect called abdominal stretch that stretches well.

  When this belly elongation occurs in an intermediate rolling mill among the finish rolling mills 18 and the extent thereof becomes severe, when rolling is performed by one rolling mill on the downstream side in the conveying direction, FIG. As shown in the figure, the stretched part is rolled in a three-ply state, and finally there is a hole as shown in FIG. 12 (b), and there is often another rolling mill on the downstream side. Therefore, the rolled material 8 often breaks due to the tension acting on the rolled material 8 between the rolling mills.

  As techniques for controlling the growth of the thermal crown D, Patent Literature 1, Patent Literature 2, Patent Literature 3, and the like have been proposed.

  In Patent Document 1, in hot rolling, as shown in FIG. 13A, the cooling water w sprayed from the cooling device 4 on the surface of the work roll 19 on the exit side of the roll bit of the work roll 19 of the rolling mill. As shown in FIG. 13 (b), the width of the material 8 to be rolled is determined as to how many of the valves 3 arranged in the body length direction of the work roll 19 are closed from the end. The flow rate of the cooling water w sprayed on the surface of the work roll 19 is changed in the body length direction of the work roll 19 by changing it according to the control, and the thermal expansion due to heat input from the material to be rolled 8 is controlled. A method has been proposed.

  In Patent Literature 2, only the lower work roll 19 is controlled so that the flow rate of the cooling water w has a distribution in the width direction based on the result of measuring the profile including the thermal expansion of the upper work roll 19 with an online roll profilometer. It is described.

  In Patent Document 2, as for the header 2 for injecting the cooling water w to the upper work roll 19, as shown in FIG. 14A, the body of the work roll 19 that comes into contact with all the material to be rolled 8 from the narrow width to the wide width. For the header 2 that supplies the cooling water w to the lower work roll 19 by dividing the cooling pipe into two systems in the longitudinal direction central area and the body length direction both outer areas of the work roll 19 across the central area, As shown in FIG. 14 (b), with respect to the center region in the body length direction of the work roll 19 that comes into contact with all the material 8 to be rolled from the narrow width to the wide width, the work has a single cooling pipe and sandwiches the center region in the body length direction. Regarding the outer side areas of the roll 19 in the body length direction, one nozzle 1 (two when counted for both outer areas) is used as a separate cooling pipe, and the flow rate of the cooling water w is individually controlled. is doing.

  In Patent Document 3, as shown in FIG. 15, a plurality of headers 2 in which the number of nozzles 1 is fixedly arranged symmetrically in the same direction with respect to the center in the body length direction of the work roll 19 are provided for each work roll 19. Moreover, it is described that the flow rate of the cooling water w is 1.2 to 1.5 times that of the lower work roll 19 with respect to the upper work roll 19.

  In both Patent Document 2 and Patent Document 3, returning to FIG. 13, as a problem peculiar to the upper work roll 19, the cooling water w tends to accumulate on the wiper 5 and the stripper 6, and the newly supplied cooling is performed. The problem is that it hinders water w.

  As a result, in Patent Document 2, only for the lower work roll 19, one nozzle 1 (two when counted for both outer regions) is used as a separate cooling pipe, and the flow rate of the cooling water w is individually controlled. In particular, in Patent Document 3, the flow rate of the cooling water w is 1.2 to 1.5 times that of the lower work roll 19 with respect to the upper work roll 19. Incidentally, in FIG. 13, reference numerals 5a and 6a denote frames.

  Patent Document 4, Patent Document 5, Patent Document 6 and the like have been proposed as to how the cooling method is changed between the center region in the body length direction of the work roll and the both outer regions thereof.

  In Patent Document 4, for the case of cold rolling, as shown in FIG. 16 (a), among the nozzles 1 arranged in a certain pitch in the body length direction of the work roll, It is proposed that the cooling water w is supplied to the nozzle 1 in the region (plate path) substantially equal to the width to perform strong cooling, and the degree of cooling is reduced in both outer regions in the body length direction of the plate path. (The nozzle shown in FIG. 16 (a) is a solid nozzle that performs strong cooling).

  Patent Document 5 describes that the shape of the material to be rolled 8 after rolling can be flattened if the slope of the portion corresponding to C ′ in FIG. In addition, a shape detector that detects how the elongation in the longitudinal direction of the material to be rolled 8 is distributed in the width direction is installed, and the output result is controlled by the roll bending force control and the flow rate of the cooling water w in the body length direction. It also describes that it is reflected in the control of how the distribution is performed.

In patent document 6, it is equivalent to C 'of the said patent document 5 for the case where the width difference is 50 mm or less by the rolling material 8 preceded by hot rolling, and subsequent rolled material 8 by hot rolling. Rather than steeping the slope of the portion to be rolled, the idea that the shape of the material 8 after rolling can be flattened is pushed one step further, and as shown in FIG. Of the nozzles 1 arranged in a certain pitch at a certain condition, in a region (plate path) substantially coincident with the width of the material 8 to be rolled, cooling is performed within a range of 100 to 200 mm from the width end of the material 8 to be rolled. It has been proposed to reduce the degree of cooling of the nozzle 1 that supplies the water w (the nozzle shown in FIG. 16 (b) that is solidly cooled).
JP 58-135709 A Japanese Patent No. 3088904 Japanese Patent Laid-Open No. 10-291011 Japanese Patent Publication No. 07-066756 Japanese Examined Patent Publication No. 62-040081 JP 2001-340908 A

  However, even with the techniques of Patent Documents 1 to 6, there is a limit to the effect. As the flow rate of supplying the cooling water w to the work roll 19 increases, the cooling efficiency is likely to increase by that amount. However, actually, even if the flow rate is increased, a water film is formed on the work roll 19, and a new film is formed. The loss due to the cooling water w supplied to the slag being hindered and flowing out without reaching the surface of the work roll 19 is large.

  The present invention has been made to solve such a problem of the prior art, and the cooling efficiency when cooling the work roll 19 of the metal plate rolling mill with the cooling water w has a distribution in the body length direction. By performing such control satisfactorily, the flatness of the rolled material 8 after rolling can be ensured, and troubles such as perforations due to belly elongation of the rolled material 8 can be effectively prevented. An object of the present invention is to provide a method for cooling a work roll in rolling a metal plate and a method for producing a metal strip using the work roll.

The present invention for achieving such an object is as follows. That is,
(1) A work roll cooling device for a metal sheet rolling mill, wherein the pressure of cooling water supplied to the surface of the work roll of the metal sheet rolling mill is variable in the body length direction of the work roll.
(2) Rolling of a metal plate characterized in that the pressure of the cooling water supplied to the surface of the work roll of the metal plate rolling machine is higher in the central region in the body length direction of the work roll than in both outer regions. Method for cooling work rolls.
(3) A method for producing a metal plate using the work roll cooling method of (2).

  According to the present invention, it is possible to satisfactorily perform control such that the cooling efficiency when cooling the work roll 19 of the metal sheet rolling mill with the cooling water w is distributed in the body length direction. . As a result, the flatness of the rolled material 8 after rolling can be ensured, and troubles such as perforations due to belly elongation of the rolled material 8 can be effectively prevented.

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
Fig.1 (a) is a side view which shows schematic arrangement | positioning of the cooling device which is an example of embodiment of this invention. 4 is the cooling device of the present invention. The surface of the work roll 19 is cooled with the cooling water w supplied from the cooling device 4.

  A is the conveyance direction of the material 8 to be rolled. Hereinafter, the side toward the transport direction A is referred to as a downstream side or an exit side, and the opposite side is referred to as an upstream side or an entry side. In addition, the part which the work roll 19 and the to-be-rolled material 8 are actually contacting in the case of rolling shown by F in FIG. 1 (a) is called a roll bite. θ is an angle viewed in the rotation direction A ′ of the work roll 19 with respect to the exit end of the roll bite F.

The cooling device 4 may be installed not only on the exit side of the roll bite F when viewed in the rotation direction A ′ of the work roll 19 but also at other positions when viewed in the entrance side and the rotation direction A ′.
In order to suppress as much as possible that the cooling water w from the cooling device 4 that jets the cooling water w onto the surface of the work roll 19 gets on the material 8 to be rolled, the wiper 5 and the stripper 6 and the frame 5a connected to them, 6a is installed. M is a rolling mill equipped with these devices.

  FIG. 1B is a front view showing the above-described cooling device 4, the work roll 19, and the material to be rolled 8 when viewed from the exit side of the work roll 19 in the body length direction of the work roll 19. .

  As shown by 4 in FIG. 1 (b), the cooling device 4 is a region that covers a width greater than the width of the material 8 having the maximum width to be rolled in the body length direction of the work roll 19, or the work roll. It installs so that the cooling water w can be supplied with respect to the surface of 19 trunk | drum length direction whole areas.

  Here, the cooling device 4 of the present invention refers to a range including the piping system after the pump. Turning to FIG. 2, the cooling water w is supplied to the cooling device 4 through piping, and the valve 3 is opened and closed by switching commands from the control device 50 not shown in FIG. 2. The supply of the cooling water w to the nozzles 1a, 1b,... Can be set to a low pressure of, for example, 0.1 MPa by the pump P for each nozzle, or can be, for example, 20 MPa by two-stage pressure increase by the pump P and the pump P ′. It is possible to switch so that a high pressure can be achieved.

  The specific range of low pressure and high pressure is not so clear as to what should be determined critically under what conditions, but from the standpoint of reality such as mechanical specifications such as pump flow rate and power consumption, it is roughly a guideline. The low pressure is preferably 0.1 to 3 MPa, and the high pressure is preferably 5 to 60 MPa.

  Further, in the cooling device 4 of the present invention, one or more other nozzles may be connected to a common pipe as shown by a dotted line in FIG. 2, for example, in the case of the nozzle 1a. Even if this is, for example, the nozzle 1b, there is no problem.

With the above configuration, as shown in FIG.
(A) Cooling piping between the body length direction central region of the work roll 19 that contacts all the workpieces 8 from narrow to wide, and both outer regions in the body length direction of the work roll across the body length direction central region Is differentiated into two systems (upper work roll of Patent Document 2: FIG. 14 (a)),
(B) About the trunk length direction center area of the work roll 19 which contacts all the to-be-rolled materials 8 from narrow to wide, the cooling pipe is made into one system, and both the length directions of the work roll sandwiching the trunk length direction center area For the outer region, the cooling pipes for each nozzle 1 should be a separate system (lower work roll of Patent Document 2: FIG. 14B),
(C) Of the valves arranged in the body length direction of the work roll 19, the number of valves to be closed from the most end is changed one by one according to the width of the material to be rolled 8 (Patent Document 1). : Figure 13 (b))
Any of the embodiments can be realized.

  Of course, as shown in Patent Document 2 (FIG. 14) and Patent Document 3 (FIG. 15), the header 2 can be formed in a plurality of rows. The work roll method and the metal plate manufacturing method of the present invention can be realized with such a pipe configuration.

Of the nozzles 1 arranged in the body length direction of the work roll, which nozzle 1 is used to supply the cooling water w to the width of the material 8 to be rolled,
(I) The cooling water w is supplied to the nozzle 1 in the region (plate path) substantially coincident with the width of the material 8 to be rolled, and the supply of the cooling water w is stopped or cooled in both outer regions in the body length direction of the plate path. (The flow rate of the cooling water w is relatively small) (Patent Document 4: FIG. 16 (a)))
(Ii) The degree of cooling of the nozzle 1 that supplies the cooling water w in a range of 100 to 200 mm from the width end of the material 8 to be rolled, in a region (sheet path) that substantially matches the width of the material 8 to be rolled. (Patent document 6: following FIG. 16 (b)),
Any method may be used.

Alternatively, as shown in FIG.
(Iii) Supply of the cooling water w is performed in a region (plate path) substantially coincident with the width of the material 8 to be rolled and a region partially applied to both outer sides in the body length direction of the plate path. Even if the supply is stopped or the degree of cooling is reduced (the flow rate of the cooling water w is relatively small), since a certain effect can be expected, such an embodiment also falls within the scope of the present invention.

  In any case, in the present invention, the pressure of the cooling water w supplied to the surface of the work roll 19 of the metal sheet rolling mill M is changed to the work roll 19 while following the methods of the conventional patent documents to some extent. In the center region in the body length direction, the point of making it higher than both outer regions is greatly different, so that the case of the present invention is shown in FIG. Thus, since the pressure of the cooling water w is increased, the water film formed on the surface of the work roll 19 is pierced and the cooling water w reliably reaches the surface of the work roll 19. Control that the cooling efficiency when cooling the work roll 19 of the metal sheet rolling mill M has a distribution in the body length direction can be performed better than in the case of using a simple method.

  As a result, the flatness of the rolled material 8 after rolling can be ensured more reliably, and it is effective for troubles such as perforation due to the stretch of the rolled material 8 shown in FIGS. Can be prevented.

An example of the effect of the implementation of the present invention will be described. For F4 of the finish rolling mill 18 in the hot rolling line 100 shown in FIG. 9 described above, as a representative case, the nozzle 1 arranged at a 50 mm pitch in the body length direction of the work roll 19 has a pressure of 1 MPa and a nozzle When supplying the cooling water w of 100 l / min per one to the surface of the upper work roll 19 having a diameter of 750 mm, the conditions are appropriately changed to determine what roll profile the work roll 19 has.
(I) In the case of no control (cooling water w is uniformly supplied over the entire length of the work roll 19),
(II) Following the method of Patent Document 6, the cooling water w is supplied in a range of 100 mm from the width end of the material 8 to be rolled, in a region (sheet path) that substantially matches the width of the material 8 to be rolled. For the nozzle 1, when the degree of cooling is reduced and the flow rate of the cooling water w is halved,
FIG. 6 also shows the case of the present invention in comparison with FIG.

In the case of the present invention,
(III) The cooling degree is reduced with respect to the nozzle 1 that supplies the cooling water w in a range of 100 mm from the width end of the material 8 to be rolled, in a region (sheet path) that substantially matches the width of the material 8 to be rolled. In addition, the flow rate of the cooling water w is halved, and the pressure of the cooling water to be supplied is increased to 20 MPa in the region where the degree of cooling is not reduced in the plate path (Patent Document 6: FIG. 16 (b). ) Followed).

In the case of this invention, it turns out that the thermal crown can be suppressed significantly. In addition, the said Example is an example to the last,
(I) The cooling water w is supplied to the nozzle 1 in the region (plate path) substantially coincident with the width of the material 8 to be rolled, and the supply of the cooling water w is stopped or cooled in both outer regions in the body length direction of the plate path. (The flow rate of the cooling water w is relatively small) (Patent Document 4: FIG. 16 (a)))
(Ii) The degree of cooling of the nozzle 1 that supplies the cooling water w in a range of 100 to 200 mm from the width end of the material 8 to be rolled, in a region (sheet path) that substantially matches the width of the material 8 to be rolled. (Patent document 6: following FIG. 16 (b)),
Needless to say, the other methods have a considerable effect.

As described above, the present invention can be applied not only to a hot rolling line of a type like the hot rolling line 100 shown in FIG. 9, but also to other types of hot rolling lines. Other types of hot rolling lines include a hot rolling line 200 directly connected to the continuous casting line 600 shown in FIG. 7 (a) and a hot rolling type called a stickel mill 300 shown in FIG. 7 (b). In addition to the rolling line, there is a hot endless rolling line 400 shown in (c) from the final roughing mill to the finishing mill and the subsequent coiler. The present invention can also be applied to the cold rolling line 500 shown in FIG.

  In any case, it is possible to satisfactorily perform control such that the cooling efficiency when cooling the work roll 19 for rolling the metal plate has a distribution in the body length direction. As a result, the flatness of the rolled material 8 after rolling can be ensured, and troubles such as perforations due to belly elongation of the rolled material 8 can be effectively prevented.

Diagram showing an example of an embodiment of the present invention Diagram showing an example of an embodiment of the present invention Diagram showing various embodiments of the present invention Diagram showing another embodiment of the present invention Diagram showing the operation of the present invention in comparison with the prior art Diagram showing the effect of the present invention in comparison with the prior art The diagram which shows the example of another various hot rolling line which should apply this invention The diagram which shows an example of the cold rolling line which should apply this invention The diagram which shows an example of the hot rolling line which should apply this invention Diagram showing the appearance of a thermal crown Diagram showing how the stomach stretches Diagram showing how the material to be rolled is perforated by stretching the belly Diagram for explaining the prior art Diagram for explaining the prior art Diagram for explaining the prior art Diagram for explaining the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle 2 Header 3 Valve 4 Cooling device 5 Wiper 5a Frame 6 Stripper 6a Frame 7 Table roll 8 Roll material 9 Width press 10 Heating furnace 12 Rough rolling mill 13 Edger roll 14 Crop shear 15 Finishing side thermometer 16 Descaling Equipment 18 Finishing mill 19 Work roll 19A Backup roll 20 Looper 21 Finishing side thermometer 22 Finishing side thickness gauge 23 Runout table 24 Coiler 25 Coiler entry side width gauge 26 High-speed sheet feeding device 27 Cutting device 30 Measuring ring 31 Crop Shear 32 High-speed threading device 33 Cutting device 35 Joining device 36 Deburring device 37 Sheet bar heater 38 Edge heater 39 Joining part cooling device 40 Furnace coiler 41 Unwinding reel 42 Joining machine 43 Loop equipment 45 Cutting machine 46 Take-up reel 50 Control device 70 Process computer 90 Business computer 100, 200 Hot rolling line 300 Steckel mill 400 Hot endless rolling line 500 Cold rolling line 600 Continuous casting line A Conveying direction A ′ Rotating direction of work roll 19 B Out of plate path C Work roll 19 Cylinder length direction central region C ′ of the roll length central region C of the work roll 19 in contact with the material 8 to be rolled 8, a region close to the outside B of the plate path D thermal crown E opening F roll bite G The region M in which the water is first cooled with the cooling water. Rolling mills P, P ′ Pump θ Angle with respect to the rotation direction A ′ of the work roll 19 when the outlet end of the roll tool F is used as a reference

Claims (3)

A work roll cooling device for a metal sheet rolling mill, wherein the pressure of cooling water supplied to the surface of the work roll of the metal sheet rolling mill is variable in the body length direction of the work roll. The work roll in rolling a metal plate, characterized in that the pressure of the cooling water supplied to the surface of the work roll of the rolling mill for the metal plate is higher in the center region in the body length direction of the work roll than in the both outer regions. Cooling method. The manufacturing method of the metal plate using the cooling method of the work roll of Claim 2.

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