JP5050796B2 - Cold rolled steel sheet manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a cold-rolled steel sheet without reaching suspension of pickling even while a cold-rolling mill is suspended without impeding productivity needlessly in continuous steel sheet processing equipment. <P>SOLUTION: Before suspending a cold-rolling mill 5, the target value of the sum total of the accumulative length of loopers 12, 13 when ending the suspension of the cold-rolling mill 5 arranged between sections 24, 26 and a threading speed during the suspension of the cold-rolling mill 5 in the section 24 are determined, the target value of the sum total of the accumulative length of the loopers 12, 13 when starting the suspension of the cold-rolling mill 5 is obtained on the basis of the predetermined suspension time of the cold-rolling mill 5, the target value of the accumulative length of the steel sheet when ending the suspension of the cold-rolling mill 5 and the threading speed during the suspension of the cold-rolling mill 5 of the section 24. By controlling the threading speed of the section 24 so as to satisfy the target value of the sum total of the accumulative length when starting the suspension of the cold-rolling mill 5, after starting the suspension of the cold-rolling mill 5, the threading speed of the section 24 is used as the threading speed during the suspension of the cold-rolling mill 5 determined before the suspension of the cold-rolling mill 5. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a cold-rolled steel sheet, and specifically, cold-rolls a peracid-washed portion generated on the surface of the steel sheet when the cold-rolled steel sheet is produced using a so-called continuous steel sheet treatment facility. In particular, the present invention relates to a method for manufacturing a cold-rolled steel sheet that can suppress breakage of the steel sheet and fluctuations in sheet thickness.

  When a cold-rolled steel sheet is manufactured by performing cold rolling on the steel sheet, the production efficiency and the yield decrease due to unsteady operations such as passing through the front end of the steel sheet and pulling out the rear end. In order to prevent this, the rear end of the preceding steel plate and the front end of the subsequent steel plate are welded by a welding machine, and the steel plate is continuously rolled. In such cold rolling, prior to cold rolling, a leveler that corrects the flatness of the steel sheet, pickling that removes the scale generated on the surface of the steel sheet, and further, the end in the width direction of the steel sheet is cut. Processing such as trimming to align the plate width is also performed. For this reason, in general, a cold-rolled steel sheet includes a welding machine for welding a preceding steel sheet and a succeeding steel sheet, a pickling tank for performing pickling, a trimmer for trimming, and cold rolling. It manufactures using the continuous steel plate processing equipment provided with the cold rolling mill to perform.

  When manufacturing a cold-rolled steel sheet while passing a steel sheet in this continuous steel sheet processing facility, when the welding point between the preceding steel sheet and the subsequent steel sheet passes through each of the devices that perform the various processes described above, Since the setting is changed according to the subsequent steel plate for each of the devices, it is necessary to decelerate the steel plate once. However, the deceleration timing is different for each device and is not the same timing. For this reason, a continuous steel sheet processing facility is divided into a plurality of sections such as, for example, a welding section including a welding machine, a pickling section including a pickling tank, and a rolling section including a cold rolling mill. By arranging a looper for imparting a deflection to the steel plate between them, the plate passing speed of each section can be individually controlled.

  By the way, when the cold rolling mill is systematically stopped and restarted for a predetermined period (for example, about 10 minutes) in order to change the roll to replace the rolling roll in this continuous steel plate processing facility, When the steel plate in the washing section stops while being immersed in the pickling solution contained in the pickling tank (hereinafter, such stop is referred to as “pickling stop” in this specification), the surface of the steel plate is Discolored peracid wash parts are generated. When this peracid pickled part is cold-rolled, it breaks or changes in thickness, resulting in a decrease in yield and productivity. Therefore, in actual operation, it is necessary not to stop pickling even when the cold rolling mill is systematically stopped for a predetermined period.

For example, in Patent Document 1, the steel sheet accumulation length in the looper arranged on the upstream side of the cold rolling mill is reduced to the minimum state before the cold rolling mill is stopped, and the cold rolling mill is stopped. The pickling speed, that is, the sheeting speed of the pickling tank, is set low based on the estimated cold rolling mill stoppage time and the accumulated steel plate length, so that the pickling can be performed even when the cold rolling mill is scheduled to stop. An invention for preventing a stop is disclosed.
JP-A-6-170430

  Patent Document 1 discloses only the case where only one looper is provided between the pickling tank and the cold rolling mill, and does not disclose the case where a plurality of loopers are provided. However, in reality, a trimmer is installed between the pickling tank and the cold rolling mill, and in this case, between the pickling tank and the trimmer and between the trimmer and the cold rolling mill. Loopers are respectively disposed, and a plurality of loopers are provided between the pickling tank and the cold rolling mill.

For this reason, even if it is based on the invention disclosed by patent document 1, it is unclear whether a pickling stop can be prevented also when a plurality of loopers are provided between the pickling tank and the cold rolling mill.
Moreover, in this invention, since the steel plate accumulation length in the looper arrange | positioned in the upstream of a cold rolling mill is reduced to the minimum state, the pickling speed falls more than necessary, and productivity falls remarkably.

The present invention relates to a continuous steel plate comprising a plurality of sections including a pickling section including a pickling facility and a rolling section including a cold rolling mill, and a plurality of loopers disposed at least between the pickling section and the rolling section. This is a method for producing cold-rolled steel sheets by using a processing facility to pass steel sheets at independent speeds for each of a plurality of sections, and stopping the cold rolling mill for a predetermined period and then operating it again. Before the cold rolling mill is stopped for a predetermined period, at the end of the predetermined period, the target value of the total sum of the steel plate accumulation length of each of the plurality of loopers arranged between the pickling section and the rolling section. of matching a certain first target value determined, the stop-time communication plate speed of pickling sections in a predetermined period, the minimum passing plate speed of pickling section does not occur over pickling section After obtaining the so that the time and the predetermined period of the cold rolling mill, the first target value and based on a stop time of passing plate speed, at the start of the predetermined time period, each of the plurality of looper steel storage The second target value, which is the target value of the sum of the lengths, was determined, the sheeting speed of the pickling section was controlled so as to satisfy the second target value, and the cold rolling mill was stopped for a predetermined period. The method for producing a cold-rolled steel sheet is characterized in that the sheet passing speed of the pickling section is controlled so as to be the sheet passing speed when stopped.

  That is, the features of the present invention are the target value of the sum total of the steel plate accumulation length of each of the plurality of loopers and the pickling speed to be taken during the stop, which are required at the end of the stop of the cold rolling mill for a predetermined period. Based on the above, the target value of the total sum of the steel plate accumulation lengths of the plurality of loopers, which is required at the start of the stop of the cold rolling mill for a predetermined period, is obtained by back calculation. The present invention is not intended to prevent the occurrence of over pickling simply by minimizing the steel plate accumulation length of the looper as in the invention disclosed in Patent Document 1 described above, Using the stop time and the pickling speed to be taken during this stop, control is performed to achieve the desired steel sheet accumulation length at the end of the stop of the cold rolling mill for a predetermined period, that is, when returning to normal operation It is.

  Here, the desirable steel plate accumulation length is a target value for the sum of the steel plate accumulation lengths of the plurality of loopers after the pickling tank and before the cold rolling mill.

  According to the present invention, a continuous steel plate comprising a plurality of sections including a pickling section including a pickling facility and a rolling section including a cold rolling mill, and a plurality of loopers disposed at least between the pickling section and the rolling section. When processing a cold-rolled steel sheet by processing a steel sheet at an independent speed for each of a plurality of sections using a processing facility, and operating again after stopping the cold rolling mill for a predetermined period, Without impeding productivity more than necessary, it is possible to produce a cold-rolled steel sheet without stopping pickling even when the cold rolling mill is stopped.

  For this reason, according to the present invention, it is possible to suppress breakage and plate thickness fluctuation caused by cold rolling the peracid-washed portion generated on the surface of the steel plate, thereby improving the yield and productivity of the steel plate. Can be prevented.

Hereinafter, the best mode for carrying out the method for producing a cold-rolled steel sheet according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram schematically showing the configuration of the continuous steel plate treatment facility 0 of the present embodiment. Since this continuous steel plate processing facility 0 includes the steel plate continuous processing facility 10 and the control device 80, these will be described.

[Steel plate continuous treatment equipment 10]
As shown in FIG. 1, the steel plate continuous processing facility 10 of the present embodiment includes a welding section 23 including a rewinding machine 1 and a welding machine 2, a pickling section 24 including a pickling tank 3, and a trimmer 4. A trimmer section 25 and a rolling section 26 including a cold rolling mill 5 and a winder 6 are provided.

  Further, the entrance looper 11 is disposed between the welded section 23 and the pickling section 24, the central looper 12 is disposed between the pickling section 24 and the trimmer section 25, and the trimmer section 25 and the rolling section 26 are further disposed. An exit looper 13 is disposed between the two.

  The rewinding machine 1 pays out while rewinding the second steel plate 22 wound in a coil shape. The tip of the discharged second steel plate 22 is welded to the rear end of the preceding first steel plate 21 by the welding machine 2 to form a steel plate 20. A steel plate 20 is continuously supplied to the inlet side looper 11, the pickling tank 3, the central looper 12, the trimmer 4, the outlet side looper 13, and the cold rolling mill 5 that are sequentially arranged downstream of the welding machine 2. The

  The steel plate 20 is guided to the pickling tank 3 and pickled, and after that, the end portion in the plate width direction is trimmed by the trimmer 4 to a predetermined plate width, and then rolled by the cold rolling mill 5 to obtain a predetermined plate width. The thickness is reduced to the plate thickness. Furthermore, a cold-rolled steel sheet as a product is manufactured by being wound in a coil shape by the winder 6.

  Since the entrance side looper 11 is disposed between the welding machine 2 and the pickling tank 3, that is, between the welding section 23 and the pickling section 24, the steel plate 20 in the welding section 23 on the upstream side of the entrance side looper 11 is arranged. The sheet feeding speed and the sheet feeding speed of the steel plate 20 in the pickling section 24 on the downstream side of the entry-side looper 11 can be set to individual speeds to pass the steel sheet 20.

  Further, since the central looper 12 is installed between the pickling tub 3 and the trimmer 4, that is, between the pickling section 24 and the trimmer section 25, the steel plate 20 in the pickling section 24 on the upstream side of the central looper 12 is provided. The steel plate 20 can be passed by setting the plate passing speed and the plate passing speed of the steel plate 20 in the trimmer section 25 on the downstream side of the central looper 12 to individual speeds.

  Furthermore, since the exit side looper 13 is installed between the trimmer 4 and the cold rolling mill 5, that is, between the trimmer section 25 and the rolling section 26, in the trimmer section 25 on the upstream side of the exit side looper 13. The plate passing speed of the steel plate 20 and the plate passing speed of the steel plate 20 in the rolling section 26 on the downstream side of the exit side looper 13 can be set to individual speeds to pass the steel plate 20.

  In addition, while welding the 1st steel plate 21 and the 2nd steel plate 22 with the welding machine 2, the inlet speed of the entrance side looper 11 and the speed paid out from the unwinding machine 1 differ, Therefore, in the following description, it is referred to as "welding. “Section speed” means the inlet speed of the entrance-side looper 11. On the other hand, when the steel plate 20 is rolled by the cold rolling mill 5, the sheet passing speed of the steel plate 20 increases. Therefore, in the following description, the “rolling section speed” is the outlet speed of the exit side looper 13, that is, the cold rolling mill. An inlet speed of 5 is meant.

  The steel plate continuous processing facility 10 in the present embodiment is configured as described above. Next, the control device 80 will be described.

[Control device 80]
As shown in FIG. 1, the control device 80 includes a result collection device 30, a section speed calculator 40, a looper protection control device 50, a looper accumulation length control device 60, and a speed control device 70.

  The performance collecting device 30 is configured to detect the position of the welding point of the first steel plate 21 and the second steel plate 22, the sheet passing speed of the steel plate 20 in each of the welding section 23, the pickling section 24, the trimmer section 25, and the rolling section 26, and Collects various actual values such as the accumulated length of the steel plate 20 in each of the inlet side looper 11, the central looper 12 and the outlet side looper 13 in real time when the steel plate continuous processing facility 10 is in operation, and these actual values are section speed calculators. 40 and the looper protection controller 50 respectively. Further, the result collecting device 30 outputs the collected actual value of the accumulated length of the steel plate 20 in the central looper 12 and the outgoing looper 13 and the actual value of the sheet passing speed of the rolling section 26 to the looper accumulated length control device 60. To do.

  The section speed calculator 40 is configured to reduce the speed when the welding point passes through the welding machine 2, the pickling tank 3, the trimmer 4, the cold rolling mill 5, or the winder 6, and the first steel plate 21 and the welding machine 2. In welding section 23, pickling section 24, trimmer section 25 and rolling section 26, which are determined independently regardless of other sections, such as deceleration and stop of welding section 23 when welding second steel plate 22, respectively. The plate passing speed is obtained and output to the speed control device 70.

  The looper protection control device 50 obtains plate passing speeds in the sections 23 to 26 for protecting and controlling the loopers 11 to 13 based on the accumulated length of the steel plates 20 in the loopers 11 to 13, and the speed control device 70. Output to.

  The looper accumulation length control device 60 is provided in the central looper 11 and the outgoing looper 12 based on the actual value of the accumulated length of the steel plate 20 in the central looper 12 and the outgoing looper 13 and the actual value of the sheet passing speed of the rolling section 26. The sheet passing speed in the pickling section 24 is obtained so as to adjust the sum of the accumulated lengths of the steel plates 20 and output to the speed control device 70.

  Furthermore, the speed control device 70 calculates a final speed command based on the plate speeds output from the section speed calculator 40, the looper protection control device 50, and the looper accumulation length control device 60, respectively, and obtains the obtained speed. By outputting the command to the welding section 23, the pickling section 24, the trimmer section 25, and the rolling section 26, respectively, the sheet feeding speed in the welding section 23, the pickling section 24, the trimmer section 25, and the rolling section 26 is controlled. .

Next, operations of the section speed calculator 40, the looper protection control device 50, the looper accumulation length control device 60, and the speed control device 70 will be described more specifically.
First, the operation of the section speed calculator 40 will be described. The section speed calculator 40 shown in FIG. 1 is a welding section speed upper limit value that is independently determined independently of other sections based on the welding point results (welding point position information) given by the result collecting device 30. V _{E, 1} , pickling section speed upper limit value V _{P, 1} , trimmer section speed upper limit value V _{T, 1} and rolling section speed upper limit value VR _{, 1} are obtained.

These speed upper limit _V E for each _{section, 1, V} P, _{1, V T, 1} and _{V R, 1} is or is passed through the welded portion of the steel plate 20 at a low speed, the first steel plate welding machine 3 21 is an upper limit value of the plate passing speed determined for performing deceleration and stop for welding the 21 and the second steel plate 22, and is obtained by a well-known and conventional method.

For example, the welding section speed upper limit value _{VE, 1} is determined as the rear end pull-out speed from when the rear end of the first steel plate 21 comes out of the rewinder 1 to when the rear end moves to the welder 2. It is 0 during welding, and is determined as the maximum speed of the rewinding machine 1 in other cases.

The pickling section speed upper limit value VP _{, 1} is determined as the pickling plate speed of the welded portion while the welded portion passes the pickling rod 3, and is determined as the maximum speed of the pickling section 24 in other cases. .

The trimmer section speed upper limit V _{T, 1} is determined as the trimmer passage speed of the welded part before and after the welded part passes through the trimmer 4, and is determined as the maximum speed of the trimmer section 25 in other cases.

Furthermore, the rolling section speed upper limit value VR _{, 1} is determined as the cold rolling mill passing plate speed of the welded portion when the welded portion passes through the cold rolling mill 5, and otherwise the cold rolling mill. 5 is determined as the maximum rolling speed determined by the rotational speed of the motor 5 and the upper limit of the output.

Next, the operation of the looper protection control device 50 will be described. 2 shows, based on the actual values of the accumulated lengths of the steel plates 20 in the entrance side looper 11, the center looper 12, and the exit side looper 13, which are given to the looper protection control device 50 from the result collection device 30, the entrance side looper 11, the center Welding section speed upper limit value V _{E, 2} , pickling section speed upper limit value V _{P, 2} , trimmer section speed upper limit value V _{T, 2} for controlling the accumulated length of steel plate 20 in looper 12 and outlet looper 13, respectively It is a flowchart which shows the procedure which calculates | requires rolling section speed upper limit VR _{, 2} .

  Briefly, the looper protection control device 50 is configured such that the accumulated length of the steel plate 20 in each of the entrance side looper 11, the center looper 12, and the exit side looper 13 exceeds the facility limit, and the entrance side looper 11, the center looper 12, and In order to prevent each of the exit side loopers 13 from being destroyed, in each of the welding section 23 upstream of the entry side looper 11, the pickling section 24 upstream of the central looper 12, and the trimmer section 25 upstream of the exit side looper 13. The pickling section 24 downstream of the entry side looper 11 so as to suppress the sheet passing speed of the steel sheet 20 and not to break through the lower limit of the accumulation length of the steel sheet 20 in each of the entry side looper 11, the central looper 12 and the exit side looper 13. Downstream of the trimmer section 25 downstream of the central looper 12 and the outlet looper 13 Regulating the sheet passing speed of the extending section 26 steel 20 in each.

In step (hereinafter abbreviated as “S”) 1 in FIG. 2, the upper limit speeds VP _{and ENT} of the pickling section 24 are calculated so that the accumulated length of the steel plate 20 in the entry side looper 11 does not exceed the lower limit. Set by. Then, the process proceeds to S2.

In S2, the speed upper limit values _VE and _ENT of the welding section 23 are set by calculation so that the accumulation length of the entry side looper 11 does not exceed the upper limit. Then, the process proceeds to S3.

In S3, speed upper limit values V _{T and MDL} of the trimmer section 25 are set by calculation so that the accumulated length of the steel plate 20 in the central looper 12 does not exceed the lower limit. Then, the process proceeds to S4.

In S4, speed upper limit values _VP and _MDL of the pickling section 26 are set by calculation so that the accumulated length of the steel plate 20 in the central looper 12 does not exceed the upper limit. Then, the process proceeds to S5.

In S5, speed upper limit values VR _{and DEL} of the rolling section 26 are set by calculation so that the accumulated length of the steel plate 20 in the exit side looper 13 does not exceed the lower limit. Then, the process proceeds to S6.

In S6, the speed upper limit values V _{T and DEL} of the trimmer section 25 are set by calculation so that the accumulated length of the steel plate 20 in the outlet looper 13 does not exceed the upper limit. Then, the process proceeds to S7.

In S7, the speed upper limit of the pickling sections 24 obtained by S1~S6 _{V P, ENT,} speed upper limit _{V E} of the welding section _{23, ENT,} speed upper limit _{V T} of trimmer section _{25, MDL,} pickling section 26 speed upper limit values _{VP and MDL} , rolling section 26 speed upper limit values VR _{and DEL} , and trimmer section 25 speed upper limit values V _{T and DEL} are compared in magnitude, and the minimum value is stored in the looper. The welding section speed upper limit value V _{E, 2} , pickling section speed upper limit value V _{P, 2} , trimmer section speed upper limit value V _{T, 2} and rolling section speed upper limit value VR _{2, 2} are set.

The welding section speed upper limit value VE _{, 2} , the pickling section speed upper limit value VP _{, 2} , the trimmer section speed upper limit value V _{T, 2} and the rolling section speed upper limit value VR _{, 2} by the looper accumulation length control device 50 are publicly known. It can obtain | require by the method of.

Briefly, for example, the speed limit V _P pickling section 24 for storing the length of the steel plate 20 in the entry side looper 11 does not break through the lower _{limit, ENT} is steel 20 in the pickling section 24 reduced at reduction gear ratio a _P The length of the steel plate 20 pulled out from the entry side looper 11 from the start to the stop is the actual value L _ENT of the accumulated length of the steel plate 20 in the entry side looper 11 and the physical steel plate of the entry side looper 11. It is _calculated as V _{P, ENT} = {2a _P (L _ENT -L _{MIN, ENT} )} ^{1/2 so} as not to be larger than the difference from the lower limit value L _{MIN, ENT of} 20 storage lengths.

Speed upper limit V _E of the welding section 23 for storing the length of the steel plate 20 in the entry side looper 11 does not break through the upper _{limit, ENT} is steel 20 in the welding section 23 is stopped from the start of deceleration at the deceleration rate a _E The length of the steel plate 20 flowing into the entry side looper 11 is the empty length of the entry side looper 11 (the upper limit values L _{MAX and ENT} of the physical steel plate 20 accumulation length of the entry side looper 11 and the entry side. _so as not more than the difference) between the actual value _{L ENT} accumulation length of the steel plate 20 of the looper _{11, V E, ENT = {} 2a E (L MAX, ENT -L ENT)} is determined as ^1/2.

The speed upper limit value of the trimmer section 25 for preventing the accumulated length of the steel plate 20 in the central looper 12 from breaking the lower limit is obtained as V _{T, MDL} = {2a _T ( _LMDL- LMIN _{, MDL} )} ^1/2 .

Speed upper limit pickling section 24 for storing the length of the steel sheet 20 does not break through the upper at the center looper 12 _{is V P, MDL = {2a P} (L MAX, MDL -L MDL)} is determined as ^1/2.

The upper speed limit value of the rolling section 26 for preventing the accumulated length of the steel plate 20 in the exit side looper 13 from exceeding the lower limit is determined as VR _{, DEL} = {2a _R ( _LDEL- LMIN _{, DEL} )} ^1/2 .

Further, the speed upper limit value of the trimmer section 25 for preventing the accumulated length of the steel plate 20 in the exit looper 13 from exceeding the upper limit is V _{T, DEL} = {2a _T (L _{MAX, DEL} -L _DEL )} ^1/2 Desired.

Here, symbol a _T is a reduction rate of the trimmer section 25, symbol a _R is a reduction rate of the rolling section 26, symbol L _MDL is an actual value of the accumulated length of the steel plate 20 in the central looper 12, and symbol L _{MIN and MDL} are the lower limit values of the physical steel plate 20 accumulation length in the central looper 12 _, and the symbols L _{MAX and MDL} are the upper limit values of the physical steel plate 20 accumulation length in the central looper 12, and the symbol L _DEL is The actual value of the accumulated length of the steel plate 20 in the exit side looper 13, the symbols L _{MIN and DEL} are the lower limit values of the accumulated length of the physical steel plate 20 in the exit side looper 13, and the symbols L _{MAX and DEL} are the output values. This is the upper limit value of the physical accumulation length of the steel plate 20 in the side looper 13.

Next, the operation of the looper accumulation length control device 60 will be described. FIG. 3 is based on the actual value of the accumulated length of the steel plate 20 of the central looper 12 and the outgoing looper 13 and the actual value of the sheet passing speed of the rolling section 26 given to the looper accumulated length control device 60 from the actual collecting device 30. Te is a flow chart showing the procedure for obtaining the pickling section speed upper limit V _{P, 3} for controlling the sum of the accumulated length of the steel plate 20 of the central looper 12 and the exit-side looper 13.

In S1 in FIG. 3, it is determined whether or not it is time to control the total accumulated length of the steel plates 20 of the central looper 12 and the exit side looper 13, and if it is not the control timing, the looper accumulated length control device 60 performs the pickling section 24. Since it is not necessary to control the speed, the pickling section speed upper limit value VP _{, 3 is set} to ∞, the calculation is terminated, and if it is the control timing, the process proceeds to S2.

  Here, “the control timing is” means that before the cold rolling mill 5 is stopped (for example, when the cold rolling mill 5 is stopped, a welding point that should come to the inlet of the cold rolling mill 5 passes through the trimmer 4. It is defined from the time when the cold rolling mill 5 is stopped.

In S2, it is determined whether or not the cold rolling mill 5 is stopped. If the cold rolling mill 5 is stopped, the pickling section speed upper limit value V _{P and 3} are obtained before stopping, and the passage of the pickling section 24 being stopped is determined. The plate speed is set to V _stop (determined in S4, which will be described later before the cold rolling mill 5 is stopped), the calculation is terminated, and if it is not stopped, the process proceeds to S3.

In S3, it determines a target value (first target value) L _f of the steel sheet 20 sum of the respective storage length of the central looper 12 and the exit-side looper 13 at the end of the stopping of the cold rolling mill 5. The target value L _f of the total accumulated length is determined so that the pickling section 24 does not stop immediately even if the cold rolling mill 5 stops due to a trouble, so that the steel plates 20 in the central looper 12 and the outlet looper 13 are not stopped. It is desirable to determine that there is a margin with respect to the physical upper limit value of the accumulation length. For example, a value obtained by subtracting a predetermined margin from the physical upper limit value is exemplified. Then, the process proceeds to S4.

In S4, the plate _feed speed V _stop of the pickling section 24 when the cold rolling mill 5 is stopped is determined. For example, the minimum sheet feeding speed of the pickling section 24 that does not produce a per-acid pickled portion whose surface changes in color on the steel plate 20 is set to the sheet feeding speed V of the pickling section 24 when the cold rolling mill 5 is stopped. _Let it be a _stop . Then, the process proceeds to S5.

In S5, it calculates a target value (second target value) L _s accumulation length of the sum of the central looper 12 and the exit-side looper 13 steel 20 in each at the beginning of the stopping of the cold rolling mill 5. Specifically, when the scheduled stop time of the cold rolling mill 5 is T, the length (V _stop × T) of the steel plate 20 sent out from the pickling section 24 while the cold rolling mill 5 is stopped is by subtracting from the first target value _{L f, -} obtaining the target value _{L s} as _{{L f (V stop × T} )}. Then, the process proceeds to S6.

In S6, the sum (L _MDL + L _DEL ) of the accumulation length L _MDL of the steel plate 2 in the central looper 12 and the accumulation length L _DEL of the steel plate 20 in the exit side looper 13 is matched with the target value L _s obtained in S5. Pickup section speeds VP _{, 3 for this} are determined by calculation. To determine the pickling section velocity _{V P, 3,} may be a known synchronous control method, for example, when the sheet passing speed of the rolling section 26 is _{V R is, V P, 3 = V R} - {2a _{P (L MDL + L DEL -L} s)} can be determined as ^1/2. However, pickling sections velocity V _{P, 3,} so as not to slow enough excessive pickling section surface of the steel plate 20 is discolored occurs, the minimum speed of the pickling sections 24 and lower.

Finally, the operation of the speed control device 70 will be described. The speed control device 70 includes: (i) a welding section speed upper limit value V _{E, 1} , a pickling section speed upper limit value V _{P, 1} , a trimmer section speed upper limit value V _{T, 1} and rolling input from the section speed calculator 40. Section speed upper limit values VR _{, 1} and (ii) a welding section for controlling the accumulated length of the steel sheet 20 in each of the entry side looper 11, the central looper 12, and the exit side looper 13 input from the looper protection control device 50. From speed upper limit value VE _{, 2} , pickling section speed upper limit value VP _{, 2} , trimmer section speed upper limit value VT _{, 2} and rolling section speed upper limit value VR _{, 2} , (iii) from looper accumulation length control device 60 Pickling section speed upper limit value V _P for controlling the sum of the accumulated lengths of the steel plates 20 of the input central looper 12 and the outgoing looper 13 _{, 3} Based on the bets, set to indicate the speed command _{V E} with respect to the weld section 23, the speed command _{V P} for pickling section 24, the speed command _{V T} for the trimmer section 25, and a speed command _{V R} for rolling section 26 below .

V _E = min (V _{E, 1} , V _{E, 2} )
V _P = min (V _{P, 1} , V _{P, 2} , V _{P, 3} )
V _T = min (V _{T, 1} , V _{T, 2} )
V _R = min (V _{R, 1} , V _{R, 2} )

That is, the speed command V _E with respect to the weld section 23, a welding section speed upper limit V _{E, 1} input from the section speed calculation unit 40, a welding section speed upper limit V _E which is input from the looper protection and control device _{50, 2} And set it as the smaller value of
Speed command V _P for pickling section 24 includes a pickling section speed upper limit V _{P, 1} input from the section speed calculation unit 40, the pickling section speed upper limit V _P input from the looper protective control apparatus _{50, 2} and the pickling section speed upper limit value VP _{, 3} input from the looper accumulation length control device 60 is set as the smallest value,
The speed command V _T for the trimmer section 25 is set as a smaller value of the trimmer section speed upper limit value V _{T, 1} and the trimmer section speed upper limit value V _{T, 2} input from the section speed calculator 40, and ,
Speed command V _R for rolling section 26 includes a rolling section speed upper limit V _{R, 1} is input from the section speed calculation device 40, the rolling section speed upper limit V _{R, 2} inputted from the looper protective control apparatus 50 Set as the smaller value.

  In this way, the speed control device 70 sets the plate passing speed of the steel plate 20 in each of the welding section 23, the pickling section 24, the trimmer section 25, and the rolling section 26, and the welding section 23, the pickling section 24, the trimmer section. 25 and the rolling section 26 are output to the drive units of the steel plate conveying devices.

Thus, according to the present embodiment, the four sections 23 to 26 including the pickling section 24 including the pickling equipment 3 and the rolling section 25 including the cold rolling mill 5, the pickling section 24 and the rolling When rolling the steel plate 20 at an independent speed for each of the sections 23 to 26 using the continuous steel plate processing facility 0 including the two loopers 12 and 13 disposed between the sections 26, a cold rolling mill When producing cold-rolled steel sheet by operating 5 again after stopping for a predetermined period,
(I) Before stopping the cold rolling mill 5 for a predetermined period, the first target value L _f that is the target value of the total sum of the steel plate accumulation lengths of the two loopers 12 and 13 at the end of the predetermined period And the _stop plate passing speed V _{stop of the} pickling section in a predetermined period, the predetermined time period T of the cold rolling mill 5, the first target value L _f and the stop plate passing speed. Based on V _stop , the second target value L _s , which is the target value of the total sum of the steel plate accumulation lengths of the loopers 12 and 13 at the start of the predetermined period, is obtained, and the second target value L _s is satisfied. controls the sheet passing speed V _P of the pickling section as,
(Ii) After the cold rolling mill 5 starts to be stopped for a predetermined period, the sheet feeding speed of the pickling section is controlled so as to become the sheet _feeding speed V _stop at the time of stopping.

  According to this embodiment, even when the cold rolling mill 5 is systematically stopped for a predetermined time in the continuous steel plate processing facility 0, the pickling is stopped without impeding productivity more than necessary. Therefore, the cold-rolled steel sheet can be reliably manufactured.

  Thereby, the fracture | rupture and board | plate thickness fluctuation | variation which generate | occur | produce resulting from cold-rolling the peracid wash part which generate | occur | produces on the surface of the steel plate 20 can be suppressed, and, thereby, the yield and productivity fall of the steel plate 20 are reduced. Can be prevented.

  Furthermore, the present invention will be described more specifically with reference to the results of simulation performed under the conditions shown in Table 1. In the following description, a welding point closest to the cold rolling mill among a plurality of welding points existing on the steel plate 20 is referred to as a welding point a, and hereinafter referred to as a welding point b, a welding point c,. I will do it.

  In the continuous steel sheet processing facility 0 having the specifications shown in FIG. 1, assuming that the roll of the cold rolling mill 5 is changed, a simulation was performed to systematically stop the cold rolling mill 5 for 11 minutes.

  The target value of the accumulated length of the steel plate 20 in the central looper 12 and the outgoing looper 13 at the end of the stop of the cold rolling mill 5 (the accumulated length of the steel plate 20 in the central looper 12 + the accumulated length of the steel plate 20 in the outgoing looper 13) is The physical upper limit value of 840 m (physical looper 12 physical so that the cold rolling mill 5 can continue operation at a minimum speed of 0.5 m / s of the pickling section 24 even if the cold rolling mill 5 stops for 5 minutes due to trouble. The upper limit value 210 m and the physical upper limit value 630 m of the exit side looper 13) are set to 690 m in order to leave a margin of 150 m.

The simulation results according to the present invention are shown graphically in FIG.
The graph shown in FIG.
Accumulated length of the steel plate 20 in the entry side looper 11 (ingress side loop steel plate accumulation length),
Accumulated length of steel plate 20 in central looper 12 (central loop steel plate accumulated length),
Accumulated length of the steel plate 20 in the outgoing looper 13 (outgoing loop steel plate accumulated length),
Accumulated length of steel plate 20 in central looper 12 and outlet looper 13 (central loop steel plate accumulated length + outside loop steel plate accumulated length),
The plate passing speed of the steel plate 20 in the welding section 23 (incoming section speed),
Plate speed of the steel plate 20 in the pickling section 24 (pickling section speed),
The passing speed of the steel plate 20 in the trimmer section 25 (trimmer section speed) and the passing speed of the steel plate 20 in the rolling section 26 (rolling section speed).
Each value is shown over time. The same applies to the graph shown in FIG.

In this embodiment, the welding section speed upper limit value _{VE, 1} is set as 1 m / s until the rear end of the first steel plate 21 moves from the unwinder 1 to the welder 2, During welding, it was set as 0 m / s, and in other cases, it was set as 9.17 m / s, which is the maximum speed of the rewinding machine 1.

Pickling section speed upper limit V _{P, 1} is the first steel plate 21 and while the weld between the second steel sheet 22 passes the San'arai漕3 is a pickling through plate speed of the weld 2m / s In other cases, the maximum speed of the pickling section 24 was set to 2.5 m / s.

Maximum speed of the trimmer section speed upper limit V _{T, 1} is welded portion is set as 0.67 m / s is a trimer through plate speed of the weld at the front and rear 5m passing trimmer 4, otherwise trimmer section 25 It was set as 5.83 m / s.

Further, the rolling section speed upper limit value VR _{, 1} is set as 0.825 m / s, which is the cold rolling mill plate speed of the welded portion while the welded portion passes through the cold rolling mill 5, and the others. In this case, it was set as 2.67 m / s which is the maximum rolling speed determined from the rotational speed of the motor of the cold rolling mill 5 and the upper limit of the output.

Then, based on the procedure described above, obtaining the entry side sections velocity V _E, pickling sections velocity V _P, the trimmer section velocity V _T and rolling sections velocity V _R.
When the time B will be explained as an example in the graph of FIG. 4, since the entry-side section speed upper limit V _{E, 1} is being welded determined as 0 m / s, pickling sections speed upper limit V _{P, 1} is weld acid Since it is not passing through the washing tank 3, the maximum speed of the pickling section is determined as 2.5 m / s. The upper limit of the trimmer section speed V _{T, 1} is not located at 5 m before and after the trimmer 4, so the trimmer section 25 Is determined as 5.83 m / s, which is the maximum speed of the rolling, and further, the rolling section speed upper limit value VR _{, 1} is determined as 0 m / s for roll change.

Also, based on the flowchart shown in FIG.
The pickling section speed upper limit VP _{and ENT} for the accumulated length of the steel plate 20 in the entry side looper 11 not to exceed the lower limit are obtained as 36.6 m / s,
Obtain the entry side section speed upper limit VE _{, ENT} for the accumulation length of the steel plate 20 in the entry side looper 11 not to exceed the upper limit as 19.5 m / s,
The trimmer section speed upper limit V _{T and MDL} for the accumulation length of the steel plate 20 in the central looper 12 not to exceed the lower limit are determined as 0.5 m / s,
Pick up the pickling section speed upper limit VP _{and MDL} so that the accumulated length of the steel plate 20 in the central looper 12 does not exceed the upper limit _, and set 8.7 m / s,
Obtain the rolling section speed upper limit VR _{, DEL} for the accumulated length of the steel sheet 20 in the exit looper 13 not to exceed the lower limit as 16.1 m / s,
The trimmer section speed upper limit V _{T and DEL} for the accumulated length of the steel plate 20 in the exit side looper 13 not to exceed the upper limit are determined as 13.9 m / s,
Obtain the entry side section speed upper limit value V _{E, 2} as 19.5 m / s equal to V _{E, ENT} ,
The pickling section speed upper limit value VP _{, 2} is determined as 8.7 m / s which is min ( _VP , _ENT , VP _{, MDL} ),
Trimmer section speed upper limit value V _{T, 2} is determined as 0.5 m / s which is min (V _{T, MDL} , V _{T, DEL} ), and
The rolling section speed upper limit values VR _{and 2} were determined as 16.1 m / s equal to VR _{and DEL} .

Furthermore, based on the flowchart shown in FIG. 3, the pickling section speed upper limit value VP ₃ as an output of the looper accumulation length control device 60 was determined as 0.5 m / s.
From the above results, V _{E, 1} = 0 m / s, V _{E, 2} = 19.5 m / s, so V _E = min (V _{E, 1} , V _{E, 2} ) = 0 m / s was set. .

Since V _{P, 1} = 2.5 m / s, V _{P, 2} = 8.7 m / s, V _{P, 3} = 0.5 m / s, V _P = min (V _{P, 1} , V _{P 2} , V _{P, 3} ) = 0.5 m / s.
Further, since V _{T, 1} = 5.83 m / s, V _{T, 2} = 0.5 m / s, V _T = min (V _{T, 1} , V _{T, 2} ) = 0.5 m / s is set. did.

Furthermore, since V _{R, 1} = 0 m / s, V _{R, 2} = 16.1 m / s, V _R = min (V _{R, 1} , V _{R, 2} ) = 0 m / s was set.
Time A in FIG. 4 is the time when the looper accumulation length control device 60 starts control. In the present embodiment, the time at which the welding point that should come to the inlet of the cold rolling mill 5 when the roll is changed reaches 220 m before the cold rolling mill 5.

  In the time zone from time A to time B in FIG. 4, the accumulation length of the steel plate 20 in each of the loopers 12 and 13 until the cold rolling mill 5 stops is adjusted. The target value of the sum of the accumulated lengths of the steel plates 20 in the central looper 12 and the outlet looper 13 until the cold rolling mill 5 stops is 690 m at the end of the stop of the cold rolling mill 5. 690-0.5 × 11 × from 0.5 m / s which is the pickling speed (minimum speed of the pickling section 24) during the stop of the cold rolling mill 5 and 11 minutes of the stop time of the cold rolling mill 5 It is calculated as 60 = 360 m, and the adjustment of the accumulation length of the loopers 12 and 13 is completed by the time B when the cold rolling mill 5 stops.

  In the time zone from time B to time C in FIG. 4, since the cold rolling mill 5 is stopped, the minimum speed of the pickling section 24 is 0.5 m / s, and the steel plates in the central looper 12 and the exit side looper 13. Although the total accumulated length of 20 increases, it reaches 690 m, which is a target value at the end of the stop of the cold rolling mill 5 at time C when the stop of the cold rolling mill 5 ends, and the stop of the cold rolling mill 5 is stopped. The inside can be operated without stopping pickling by the pickling tank 3.

  Moreover, even if the cold rolling mill 5 suddenly stops immediately after restarting the cold rolling mill 5 that has been stopped, it is immediately until the total accumulated length of the steel plates 20 reaches 840 m. Stopping pickling is also prevented.

  On the other hand, the result of controlling the steel plate 20 by the conventional method is shown in a graph in FIG. In the time zone from time A to time B in FIG. 5, this conventional method is based on the accumulation of the steel plates 20 in the exit side looper 13 upstream of the cold rolling mill 5 at time B immediately before the cold rolling mill 5 is stopped. In the time zone from time B to time C during which the cold rolling mill 5 is stopped, the accumulated length of the steel plate 20 in the delivery looper 13 is reduced. The plate passing speed of the pickling section 24 is determined so as not to exceed the upper limit.

Also by this conventional method, it is possible to operate without stopping pickling even when the cold rolling mill 5 is stopped (time zone from time B to time C in FIG. 5).
However, when comparing the state of the entry side section 23 at the time C immediately after resuming the operation of the cold rolling mill 5, the welding of the welding point f is already completed in the present invention shown by the graph in FIG. In the conventional method shown by the graph in FIG. 5, the welding of the welding point f has not been started yet, and there is a great difference in the progress of the processing of the steel plate 20. This is because in the conventional method, the plate passing speed of the pickling section 24 is reduced more than necessary.

  Thus, according to the present embodiment, the cold rolling mill 5 is stopped when the steel plate 20 is being passed at an independent speed for each of the four sections 23 to 26 using the continuous steel plate processing equipment. Even when the cold rolling mill 5 is being systematically stopped without unnecessarily impeding productivity, the cold rolled steel sheet can be reliably manufactured without stopping pickling.

It is explanatory drawing which shows typically the structure of the continuous-type steel plate processing equipment of embodiment. The accumulated length of steel sheets in each of the inlet side looper, central looper and outlet side looper based on the actual value of the accumulated length of steel sheets in the inlet side looper, central looper and outlet side looper given to the looper protection control device from the result collection device Shows a procedure for obtaining a welding section speed upper limit value VE _{, 2} , a pickling section speed upper limit value VP _{, 2} , a trimmer section speed upper limit value V _{T, 2} and a rolling section speed upper limit value VR _{, 2} for controlling It is a flowchart. Based on the actual value of the central looper and outlet looper steel plate length given from the actual collecting device to the looper storage length control device and the actual value of the rolling section passing plate speed, the central looper and outlet looper steel plate It is a flowchart which shows the procedure which calculates | requires the pickling section speed upper limit VP _{and 3} for controlling the sum total of the accumulation | storage length of No .. 3 is a graph showing the results of an example of the present invention in Example 1. 6 is a graph showing the results of a comparative example in Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 0 Continuous type steel plate processing equipment 1 Rewinder 2 Welding machine 3 Pickling tank 4 Trimmer 5 Cold rolling mill 6 Winding machine 10 Steel plate continuous processing equipment 11 Inlet looper 12 Central looper 13 Outlet looper 20 Steel plate 21 Steel plate 22 Second steel plate 23 Welding section 24 Pickling section 25 Trimmer section 26 Rolling section 30 Result collecting device 40 Section speed calculator 50 Looper protection control device 60 Looper accumulation length control device 70 Speed control device 80 Control device

Claims (1)

Continuous steel plate processing equipment comprising a plurality of sections including a pickling section including a pickling equipment and a rolling section including a cold rolling mill, and a plurality of loopers disposed at least between the pickling section and the rolling section Is used to manufacture a cold-rolled steel sheet by passing the steel sheet at an independent speed for each of the plurality of sections and stopping the cold rolling mill for a predetermined period and then operating again. And
Before stopping the cold rolling mill for the predetermined period, the sum of the steel plate accumulation length of each of the plurality of loopers disposed between the pickling section and the rolling section at the end of the predetermined period A first target value that is a target value of the pickling section is obtained, and the plate passing speed at the time of stopping the pickling section in the predetermined period coincides with the minimum plate passing speed of the pickling section that does not cause a per pickling section. The plurality of at the start of the predetermined period, based on the time of the predetermined period of the cold rolling mill, the first target value and the plate speed during stoppage. A second target value, which is a target value of the total sum of accumulated steel sheet lengths of each of the loopers, is controlled to control the sheet passing speed of the pickling section so as to satisfy the second target value;
After starting the stop of the predetermined period of the cold rolling mill, the sheeting speed of the pickling section is controlled so as to be the sheeting speed at the time of the stop. Production method.

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