JPS62267007A - Method for controlling color tone on front and rear surfaces of rolling material - Google Patents

Abstract

PURPOSE:To prevent the generation of a different in the color tone between the front and rear surfaces of a rolling material by detecting the lubricating condition of a rolling mill lubricant from the difference in the current value of driving motors for a pair of work rolls and controlling the flow rate of the rolling mill lubricant according to the detected condition. CONSTITUTION:The current values of the roll driving motors 28A, 28B of the respective work rolls 26A, 26B of a tandem mill 18 are detected by a main control device 24 of the mill and the lubricating condition of the rolling mill lubricant to the rolling material is detected from the difference between the detected current values. A command is emitted to a rolling mill lubricant supplying device 22 to control a flow rate control valve 40 and a feeder pump 42 in such a manner that the lubrication of the respective work rolls 26A, 26B with the rolling mill lubricant is uniformed and that the uniform color tone is obtd. The generation of the difference in the color tones between the front and rear surfaces of the rolling material and in the longitudinal direction thereof is thus prevented without attaching special sensors to the mill and the generation of a defective product by the difference in the color tone is prevented.

Description

[Detailed description of the invention]

(Industrial Application Field 1 The present invention relates to a method for color tone adjustment on both sides of a rolled material (1), in particular,
This invention relates to an improvement in a method for controlling the color tone of the front and back surfaces of a rolled material, such as a steel strip, which is applied by a pair of upper and lower rolling rolls in a tandem cold strip mill.

[Prior art] In general, the color change on the front and back surfaces of the rolled material in a tandem cold strip mill, that is, the occurrence of color tone difference, is caused by the difference in roughness of the roll surface of the rolling roll and the lubrication state of the rolling oil on the D-roll surface. There are many things to do. 1113 The occurrence of roughness differences on the O-roll surface is prevented by controlling the timing of roll replacement based on the rolling tonnage determined empirically. [Problems that the invention attempts to solve] However,
Sufficient consideration has not been given to the occurrence of color tone differences due to the lubrication conditions of the rolling oil, etc., and therefore, there is a problem in that the color tone of the rolled steel strip cannot be made uniform. That is, in a tandem cold strip mill, if the lubrication between the work roll and the steel strip changes for some reason during rolling, there will be a temperature difference in color tone (color tone difference) on the surface of the copper strip.
There is a problem in that the rolled product becomes defective. this! 34. Differences in color tone on the surface of the strip occur in the longitudinal direction of the copper strip as it is rolled, or between the front and back surfaces of the copper strip. In particular, since cold tandem strip mills roll at high speeds, the difference in color tone on the surface of the steel strip can only be detected after rolling, and steel strips with this difference in surface color become defective. There is a problem.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and can easily detect abnormalities in the rolling oil lubrication state without attaching a special sensor to the rolling mill mouth. An object of the present invention is to provide a method for color m fJI m of the front and back surfaces of a rolled material that can prevent the occurrence of color tone differences in the longitudinal direction of the front and back surfaces of a steel strip, and color tone differences in the longitudinal direction between the front and back surfaces of a steel strip.

[Means to solve the problem]

The present invention, as shown in FIG. 1, is a method for rolling a rolled material by a pair of work rolls that are individually driven by motors and arranged opposite each other. The current field of each motor is detected respectively, and the rolling oil lubrication state for the rolled material is detected from the difference between the detected current values, and the rolling oil lubrication of each work roll is made uniform according to the detected rolling oil lubrication state. By controlling the flow rate of rolling oil supplied to each work roll,
This aims to achieve the above objectives.

[Effect 1] The present invention was made based on the following findings. FIG. 2 shows the relationship between the speed command of the work rolls during rolling and the current values of the motors of the upper and lower work rolls. As is clear from Fig. 2, a large work roll driving current is required to accelerate the rolling process, and conversely, a large work roll driving current is required to decelerate the rolling process. can be seen to decrease. especially,
When decelerating a rolling mill, current sometimes flows in the opposite direction. Further, when rolling at a constant speed, the work roll drive current is also approximately constant. Further, the upper and lower work roll drive currents are almost the same, and there is almost no difference in the drive current values. However, as shown by cylinder number A in FIG. 2, the drive current values of the upper and lower work rolls may differ greatly during rolling due to some reason. In the area marked A in FIG. 2, the work roll drive current value of the lower work roll increases, and at this time, it is considered that a lubrication abnormality has occurred in the lower work roll. The inventor of the present invention found that the point at which the abnormality of the work roll drive current occurs coincides with the point at which the difference in color tone of the steel strip occurs. That is, when we investigated the relationship between the drive current difference between the upper and lower work rolls and the incidence of defective products due to the difference in color tone of the copper strip, we obtained the results shown in FIG. 3. As is clear from the results of this investigation, it can be seen that when the difference in drive current values between the upper and lower work rolls exceeds 10%, the incidence of defective products due to color tone differences increases. Therefore, in the present invention, when a rolled material is bitten and rolled by a pair of work rolls that are individually driven by motors and are arranged opposite to each other, the current value of each motor of the pair of work rolls is and detecting the rolling oil lubrication state for the rolled material from the difference between the detected current values,
Depending on the detected rolling oil lubrication state, the flow rate of rolling oil supplied to each work roll is controlled so that the rolling oil lubrication of each work roll is uniform. this,
With this, abnormalities in the rolling oil a'fI slip condition can be easily detected without installing a special sensor at the rolling mill mouth.
It is possible to prevent the occurrence of color tone differences between the front and back surfaces of the steel strip and color tone differences between the front and back surfaces of the copper strip in the respective longitudinal directions. Embodiments Examples of the present invention will be described below with reference to the drawings. As shown in FIG. 4, the cold tandem mill line 10 that implements the method of the present invention includes a payoff reel 14 for unwinding the steel strip 12 and discharging it to the tandem mill 18 for the next process, and a payoff reel 14 for unwinding the steel strip 12 from the payoff reel 14. a tandem mill 18 that rolls the rolled steel strip 12 using a plurality of rolling stands 16; a tension reel 20 that winds up the steel strip 12 rolled by the tandem mill 18; a rolling oil supply device 22 that supplies rolling oil such as lubricating oil to the front and back surfaces; a mill master υ1111 device 24 that controls the tandem mill 18 and the rolling oil supply device 22;
It is equipped with Each stand 16 of the tandem mill 18 is equipped with a pair of upper and lower work rolls 26A, 26B, and rolling is performed by rolling contact of the upper and lower work rolls 26A, 26B with the steel strip 12. +'+ir The work lower rolls 26A are each separately provided with roll drive motors 28A and 28B. The roll drive motors 28A and 28B are controlled by speed control devices 30A and 30B to have a predetermined rotation speed.
It has been g. The speed control m devices 30A and 30B include a speed control circuit 32
, the thyristor 34, and the roll drive motor 28A.
, 28B, and a speed detector 36 consisting of a pulse generator installed in the mill main controller 24, and feeds back a signal from the speed detector 36 to the speed signal output from the mill main control device 24 to drive the roll drive motor 11u. 28
It is configured to control the rotation speeds of A and 28B. These speed wheels 11ηU mountings 30A, 30B are provided for each of the upper and lower work rolls 26A, 26B or for each stand 16, and are designed to independently control the rotation of each work roll 26A, 26B. The rotational speed commands to the speed control devices 30A and 30B are output from the mill main control device 24. Mill manager system! 2(l
The device 24 includes work rolls 26A, 2 of each stand 16.
In order to control the number of rotations of the work rolls 26A and 6B in accordance with the reciprocal of the plate thickness at the exit side of each stand 16, the work rolls 26A and 6B are controlled based on the rolling reduction ratio.
26B, and outputs this rotation speed command to the speed control devices 30A and 30B. @The rolling oil supply device 22 supplies the work roll 26A,
A spray header 3 for spraying rolling oil onto the steel strip 12 caught by the spray header 38, a flow control valve 40 for regulating the flow rate of rolling oil supplied to the spray header 38, and a rolling oil tank 42 for the spray header 38. The feeder pump 44 supplies rolling oil from the feeder pump 44. The mill manager control 21! The device 24 outputs a rolling oil supply ω command to the rolling oil supply device 22, and based on this supply command, the flow rate control valve 40 and the feeder pump 4 are controlled.
2 is controlled, and rolling oil is supplied to the steel strip 12 a predetermined number of times. The mill main control device 24 outputs a rolling oil supply system command of 100 which is proportional to the line speed of the tandem mill 18, so that the rolling oil is increased or decreased depending on the line speed. The mill master control 2'lI device 24 includes a roll drive motor 28A128 for each of the work rolls 26A and 26B.
The rolling oil lubrication state of the steel strip 12 is detected from the difference in the detected current value of B, and the rolling oil lubrication state of each work roll 26A, 26B is adjusted according to the detected rolling oil lubrication state so that the rolling oil lubrication of each work roll 26A, 26B is uniform. It is configured to control the flow rate of rolling oil supplied to 26A and 26B. Further, detection signals such as the current value of the roll drive motor, the voltage value, the tension between the stands, etc. are constantly fed back to the mill master controller 60B 24. The rolling and oil flow rate control based on the detected current value of the roll drive motor in the mill main control 71] device 24 is
This is done according to the steps shown in the figure. First, in step 100, the upper work roll 26A
The current value IU of the zero-wheel drive motor 28A is detected. Next, the process proceeds to step 102, where the current value IL of the roll drive motor 28B of the lower work roll 26B is detected. Next, proceed to step 104, and proceed to step 100.1 described above.
Based on the current values I and IL detected in step 02, the current supply gap difference 1. Calculate. 1.4 = <[u-IL)/ ((llJ+lL)
/2)・・・・・・・・・(1) In the above formula (1), the current value difference 11J-IL is the current value IU,
The current value deviation I is obtained by dividing by the average value of IL. Through the processing in step 104, it is possible to detect how the load is shared between the roll drive motors 28A and 28B. Next, the process proceeds to step 106, where the current value deviation 1. i is the upper limit α (=0.1)
Determine whether the value is greater than or not. If it is determined in step 106 that the current value deviation I is larger than the upper limit value α, it is determined that a rolling abnormality has occurred on the upper work roll 26A side, and the process proceeds to step 108. In step 108, a rolling oil correction amount is determined based on the current value deviation (ii). For example, the rolling oil correction ω is
The value is set to increase the rolling oil by 10%. Next, the process proceeds to step 110, where an operation is performed to change the rolling oil flow rate based on the rolling oil correction ω obtained in step 108 above. Next, the process advances to step 112, and after a predetermined period of time has elapsed, the process returns to step 100 described above. Further, in step 106, if it is determined that the current value deviation is less than the upper limit value α, the upper work roll 26
It is determined that no rolling abnormality has occurred on the A side, and the process proceeds to step 114. In step 114, it is determined whether the current 1 direct deviation 1 obtained in step 104 is smaller than the lower limit value β (=-0°1). If it is determined in this step 104 that the current value deviation I is smaller than the lower limit value β, it is determined that there is a rolling abnormality on the lower work roll 26B side, and the process proceeds to step 11G. In step 116, the current value deviation 1. Determine the rolling oil correction amount based on z. 91 E is rolling oil correction t
i is a value that increases the rolling oil by 10%. Next, the process proceeds to step 118, where the rolling oil flow rate is controlled so as to achieve the rolling oil correction m determined in step 116 above. Next, the process proceeds to step 112, and after a certain period of time has elapsed, the process returns to step 100 described above. If it is determined in step 114 that the current value width difference Id is equal to or greater than the lower limit value β, it is determined that no rolling abnormality has occurred on the lower work roll 26B side, and the process proceeds to step 120. In step 120, the rolling oil is used as it is without determining the rolling oil correction amount! Maintain fil. Next, the process advances to step 112, and after a certain period of time has elapsed, the process returns to step 100 for outputting 1'+ff. According to this embodiment, the current values 1u and IL of the respective roll drive motors 28A128B of the upper and lower work rolls 26A126B are detected, and based on these detected current values 1u and IL, the current value deviation 1. is calculated, and based on this calculated current value deviation, it is determined whether or not rolling abnormality has occurred on the upper work roll 26A side or the lower work roll 26B side, and the rolling oil flow rate is adjusted based on this determination result. By doing so, a uniform color tone can be achieved by 1q
JA slip condition can be achieved. This can prevent the occurrence of color tone differences between the front and R surfaces of the copper strip and color tone differences in the longitudinal direction of each of the front and back surfaces. Also, if the rolling oil lubrication condition is abnormal, the roll drive motor 28A,
By making the determination based on the detected current value of 28B, it is possible to detect an abnormality in the rolling oil lubrication state by simply using the cylinder without installing a special sensor around the rolling mill. In addition, in the above embodiment, when detecting an abnormality in the rolling oil lubrication state, the upper and lower limits α and β of the current value deviation I were set to 0.1 and −0.1, respectively. However, the present invention is not limited to this, but the values of the upper and lower limits α and β may be changed as appropriate based on the allowable color tone difference. [Effects of the Invention] As explained above, according to the present invention, an abnormality in the rolling oil rA lubrication condition can be easily detected without installing a special sensor around the rolling mill, and the difference in color tone between the front and back surfaces of the rolled material can be detected. It also has the excellent effect of being able to prevent the occurrence of color tone differences in the longitudinal direction of the front and back surfaces.

[Brief explanation of the drawing]

Fig. 1 is a flowchart without showing the gist of the method for controlling the color tone of the front and back surfaces of a rolled material according to the present invention, and Fig. 2 is a flowchart showing the mill speed command and the roll drive of the upper and lower work rolls for explaining the principle of the present invention. Figure 3 is a diagram showing the relationship between the motor current value and the defective product incidence due to the current value deviation of the roll drive motor of the upper and lower work rolls and the color tone difference, also for explaining the present invention in detail. FIG. 4 is a side view including a partial block diagram and piping diagram showing the equipment configuration of a cold tandem mill line that implements the method of the present invention; FIG. 5 is a diagram showing the relationship between
It is a flowchart which shows the control procedure of the mill main control device in the said equipment. 10... Cold tandem mill line, 12... Steel strip, 14... Payoff reel, 16... Stand, 18... Tandem mill, 20... Tension reel, 22... Rolling oil supply Apparatus, 24... Mill main control device, 26A126B... Work roll, 28A, 28B... Motor, 30A, 30B... Speed control device.

Claims (1)

[Claims] (1) When rolling a rolled material by a pair of work rolls that are individually driven by motors and arranged opposite to each other, detect the current value of each motor of the pair of work rolls, and The rolling oil lubrication state for the rolled material is detected from the difference in detected current values, and rolling oil is supplied to each work roll so that the rolling oil lubrication of each work roll is uniform according to the detected rolling oil lubrication state. A method for controlling the color tone of front and back surfaces of a rolled material, the method comprising controlling the flow rate of the rolled material.