JPH0558806B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to plate thickness control in steel plate rolling,
In particular, it relates to sheet thickness control in which AGC (self-thickness control) is started after the tip of the strip (or the rolling schedule change point in the case of continuous rolling) reaches the rolling stand.

[Conventional technology]

The relationship between the target value and the actual thickness, which is the rolling result, is unknown until the end of the strip is inserted into the rolling mill and the actual thickness of the strip is obtained using the thickness gauge at the outlet of the stand. I can't do it. Therefore, conventionally, until the measured plate thickness is obtained, the rolling position is controlled so that the plate thickness estimated from the gauge meter formula h = P / M + So + Sh becomes the target plate thickness, and once the measured plate thickness is obtained (rolling After the tip of the material reaches the thickness gauge), feedback
AGC is started, but there is a delay between the change of the stand's rolling position and the detection of the result by the time it takes for the strip to move between the stand and the plate thickness gauge, and this delay time is inversely proportional to the plate speed. , AGC starts after the plate speed exceeds the set value.

On the other hand, in a rolling stand, the oil film thickness changes depending on the plate speed (peripheral speed of the rolling rolls) and rolling force. For example, the oil film thickness of a back-up roll oil film bearing increases as the plate speed increases, and as the rolling force increases, the oil film thickness decreases. Therefore, conventionally, an oil film thickness function generator obtains an oil film thickness signal corresponding to the roll circumferential speed, a coefficient function generator obtains a correction coefficient signal corresponding to rolling force, and these two signals are multiplied. It has been proposed to correct the roll gap by calculating the oil film thickness and converting this into a roll gap correction value (rolling position correction amount) (for example, Japanese Patent Laid-Open No. 58-58927).

[Problem that the invention seeks to solve]

However, in plate thickness control that combines this oil film thickness compensation with AGC, when AGC is started, the reduction position adjustment for oil film thickness compensation comes into play, causing sudden tension fluctuations in the strip, which confuses AGC.

According to the inventor's study, this seems to be due to the fact that the reduction position adjustment corresponding to the estimated oil film thickness acts all at once.

An object of the present invention is to prevent AGC confusion due to the start of oil film thickness compensation control.

[Means for solving problems]

In order to achieve the above object, in the present invention,
At the start of AGC, the estimated oil film thickness compensation amount dm at that time
is memorized, and during execution of AGC, the reduction position is adjusted using the deviation Δd=d−dm obtained by subtracting the memorized value dm from the estimated oil film thickness compensation amount d at each time as the oil film thickness compensation amount.

[Effect]

According to this, at the beginning of AGC, the oil film thickness compensation amount (deviation Δd = d - dm) is practically zero, and AGC is started without oil film thickness compensation amount, and oil film thickness compensation control and AGC are performed smoothly. The strip thickness quickly converges to the target thickness. this
Once the AGC has stabilized, the thickness deviation equivalent to the memorized value will have been absorbed by the AGC.
Note that even if the deviation Δd changes until the AGC is stabilized, this value is small, so the fluctuation in the AGC is small.
After that, when the deviation Δd changes in response to changes in the plate speed (roll circumferential speed) and/or rolling force, a corresponding correction is added to the AGC output, and the AGC adjusts the plate as if there were no oil film thickness fluctuations. Continue thickness control. When performing oil film thickness compensation and AGC in this way, h=P/M+So+Sh+ΔSi, h=P/M+So+Sh is controlled by AGC, and ΔSi is controlled by oil film thickness compensation control.

In addition, the rolling position adjustment amount Si corresponding to the memory amount dm is
Absorbed by AGC. So is the initial rolling position, Sh is the heat crown, P is the rolling reaction force, M is the mill constant, h is the plate thickness, and ΔSi is the rolling position adjustment amount corresponding to the deviation Δd.

As a result, the tension fluctuation at the start of AGC is small, the plate thickness deviation is small, and the time it takes for the AGC to stabilize is short.

FIG. 1 shows an outline of an apparatus configuration for implementing one embodiment of the present invention. In this, 1 is a rolling machine, 2 is a rolling device, 3 is a rolling reaction force detector, 4 is a rolling position detector, 5 is a plate thickness detector, 6 is a roll peripheral speed detector, and 7
is an arithmetic control device including a feedback AGC device,
8 is a reduction position control device, and 9 is an oil film thickness compensator.

The function generator 9a of the oil film thickness compensator 9 generates an oil film thickness signal corresponding to the plate speed (roll circumferential speed) V and supplies it to the multiplier 9c, and the function generator 9b generates a correction corresponding to the rolling reaction force P. A coefficient signal is generated and applied to multiplier 9c. The multiplier 9c multiplies both signals and outputs an estimated oil film thickness value d. This d is given to a subtracter 9f and a switch 9d. The output of the subtracter 9f is a deviation Δd=d−dm obtained by subtracting the output of the memory 9e from the output of the multiplier 9c. This deviation Δd=d−dm is converted into a reduction position deviation ΔSi by a converter 9g and is provided to the arithmetic and control unit 7.

The rolling reaction force detector 3 outputs the rolling reaction force signal P, the rolling position detector 4 outputs the rolling position signal, the plate thickness meter 5 outputs the plate tip arrival signal and the measured plate thickness signal, and the roll circumferential speed detector 6 outputs the plate speed. The signal V and the oil film thickness compensation pressure reduction adjustment amount ΔSi are provided from the oil film thickness compensator 9 to the arithmetic and control device 7 .

The arithmetic control device 7 performs the above-mentioned plate thickness control based on these signals and target plate thickness data given from the host computer.

An outline of the plate thickness control by the arithmetic and control unit 7 is shown in FIG. To explain this, when the rolling reaction force signal from the rolling reaction force detector 3 indicates plate jamming (in the case of continuous rolling, the arrival of a rolling schedule change point including a welding point, etc.), the arithmetic and control unit 7 , a rolling control based on a gauge meter formula, in which the rolling position is determined so that the exit plate thickness estimated by the gauge meter formula h=P/M+So+Sh becomes the target plate thickness, and the rolling position controller 8 is set to this position.
Start (1). While performing this rolling control,
Tracking the position of the tip of strip 10,
When the amount of movement of the tip of the strip 10 reaches a value equivalent to the distance between the rolling mill 1 and the plate thickness gauge 5 (the strip 10
When the tip of the plate reaches the plate thickness gauge 5), read the actual plate thickness value hm from the plate thickness gauge 5, and correct it by introducing the deviation ε = hm - h from the target plate thickness h at this point into the gauge meter formula. Set the rolling position so that the plate thickness estimated using the gauge meter formula h=P/M+So+Sh+ε becomes the target plate thickness. The amount of movement of the tip of the strip 10 is newly tracked, and the amount of movement of the tip of the strip 10 becomes a value corresponding to the distance between the rolling mill 1 and the plate thickness gauge 5 (when the tip of the strip 10 reaches part 5 of the plate thickness total) When the rolling position reaches 5 parts of the plate thickness total), the plate speed is compared with the set value. If the plate speed is greater than the set value, it means that the AGC ON condition has been met, so first, instruct the oil film thickness compensator 9 to update the memory (close the switch 9d and return it to the rear open position), and then update the memory 9e. , the estimated oil film thickness dm at that time is stored. As a result, the output of the memory 9e becomes dm, and since the output of the multiplier 9c and the output of the memory are the same at this point, the deviation Δd=0 and ΔSi
=0.

In addition, rolling control based on the gauge meter method mentioned above
In (1), the output of the oil film thickness compensator 9 is not included in the control.

The arithmetic and control unit 7 then turns on the AGC,
The reduction position control device 8 calculates the value ΔS by adding the oil film thickness compensation change amount ΔSi to the reduction change amount ΔSa calculated by AGC.
to start AGC to correct the pressure position.
In this example, AGC is the reduction change amount ΔSa, where Δh = ΔP/M (Δh is the deviation of the measured plate thickness from the target plate thickness, and ΔP is the rolling force change required to make the deviation zero).
This is a roll-down control feedback AGC that gives a value corresponding to ΔP to the roll-down position control device 8.

Then, while performing this AGC, the board speed is referred to, and if the board speed is above the set value, this AGC
continues, and when the value falls below the set value, the AGC is turned off and rolling control (2) based on the gauge meter method is performed. Then, when the sheet is removed (in the case of continuous rolling, passing through a reduction schedule change point including a welding point), rolling is performed based on the next reduction schedule from there.

As mentioned above, after the board speed becomes less than the set value,
In rolling control (2) based on the gauge meter method, the output of the oil film thickness compensator is included. That is, the rolling position is determined so that the outlet side plate thickness estimated by the modified gauge meter formula h=P/M+So+Sh+ΔSi becomes the target plate thickness, and this is set by the rolling position control device 8.

Therefore, the oil film thickness compensation plate thickness control is performed from the time the plate speed becomes equal to or higher than the set value until the rolling is finished. The oil film thickness is thicker when the plate speed is high, so
Sufficient effects can be obtained by performing oil film thickness compensation control in this manner from the time when the plate speed exceeds the set value until the end of rolling. In other words, the plate speed normally shows a speed pattern in which the plate speed gradually increases after the plate bites, then settles down to a certain speed, and then decreases near the tail end or the point where the reduction schedule changes.
The oil film thickness compensation control is started while the plate speed is increasing, and the oil film thickness compensation control is performed in a range where the oil film thickness changes greatly, such as while the plate speed is increasing and then when the plate speed is decreasing, so it is effective. Oil film thickness compensation plate thickness control is performed over most of the range. As described above, since the oil film thickness compensation reduction adjustment amount ΔSi is 0 at the start of AGC, AGC is stabilized smoothly and quickly without causing a large tension change when AGC is turned on. Thereafter, the rolling reduction is adjusted to correspond to the amount of change in oil film thickness in accordance with the increase or decrease in plate speed and the increase or decrease in rolling force. Does not cause major disruption to AGC.

〔effect〕

As explained above, according to the present invention, a large tension change does not occur when starting AGC,
AGC stabilizes smoothly and quickly. Thereafter, the rolling reduction is adjusted to correspond to the amount of oil film thickness change in accordance with the increase or decrease in plate speed and the increase or decrease in rolling force.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overview of the configuration of a device that implements the present invention in one embodiment, and FIG.
2 is a flowchart showing an overview of control operations. 1: Rolling mill 2: Rolling down device 3: Rolling reaction force detector 4: Rolling down position detector 5: Plate thickness gauge 6: Speed detector 7: Arithmetic control device 8: Rolling down position control device 9: Oil film thickness compensation device 9a, 9b: Function generator 9c: Multiplier 9d: Switch 9e: Memory 9f: Subtractor 9g: Converter.

Claims (1)

[Claims] 1. Oil film thickness compensation plate thickness that performs AGC under predetermined conditions after the start of rolling, estimates the oil film thickness of the roll bearing based on the rolling roll speed and rolling force, and adjusts the roll gap according to the oil film thickness. In control: When starting AGC, the estimated oil film thickness of the roll bearing based on the rolling roll speed and rolling force or the oil film thickness compensation roll gap pressure value based on the estimated value is memorized, and after starting AGC, An oil film thickness compensation plate thickness control method, characterized in that a deviation obtained by subtracting the memorized value from an oil film thickness measurement value or an oil film thickness estimation value at each point in time is added to AGC as an oil film thickness compensation value.