JPS5865510A - Controlling method for sheet thickness in steel sheet rolling - Google Patents

Abstract

PURPOSE:To control the sheet thickness with high accuracy, by effectively applying both of the 1st sheet thick controlling system such as a predictive sheet thickness controlling system and the 2nd sheet thickness controlling system such as a sheet thickness controlling system using a gauge meter system. CONSTITUTION:The 1st and 2nd sheet thickness controllers 3 and 4, connected parallelly to a CPU 5, are connected to a rolling mill 2 of a cold steel-sheet rolling line 1. An information signal of temp. irregularity in the longitudinal direction of a material 6 to be rolled obtained at the time immediately after hot rolling of the preceding stage or before feeding to the cold rolling line 1, is inputted to the CPU 5 to set gains G1 and G2 of the controllers 3 and 4. The controllers 3 controls the mill 2 so as to obtain DELTAH=0 by a detected signal of a thickness gauge 7 placed at the inlet side of the mill 2. The mill 2 is equipped with a hydraulic cylinder 9 having a servovalve 8 to control the hydraulic pressure, and the controllers 3 and 4 are connected to the valve 8, and further, a rolling-down force of the mill 2 is detected by a load cell 10 to be fed back to the controller 4. The sheet thickness is controlled in a feed-forward manner by making a gain G1 lower and a gain G2 higher when the temp. irregularity of the material 6 is large, and making the G1 higher and the G2 lower when the irregularity is small.

Description

[Detailed Description of the Invention] The present invention relates to a method for controlling the thickness of a steel plate under cold pressure [K].
In particular, the first plate thickness control system controls the rolling mill reduction amount in a feedforward manner based on the plate thickness at the entrance of the rolling mill, and the first plate thickness control system controls the rolling mill reduction amount in a feedback manner based on rolling pressure fluctuations during rolling. The present invention relates to a plate thickness control method for rolling a steel plate to a desired thickness while using a second plate thickness control system of a gauge meter type GC to control the plate thickness.

Conventional plate thickness control methods using rolling reduction include predictive plate thickness control system (PIF AGC) and gauge meter type plate thickness control system (
(Commonly known as BIER Mumu GC) In most cases, one or the other is installed, and in rare cases, even if two control systems are installed,
It was only an alternative choice and no effective use was made.

In 1111mm GC, the plate thickness deviation ΔH is measured at the entrance side of the rolling mill, and the plate thickness h after rolling when rolling with a constant reduction amount is calculated.
' is controlled so that the deviation Δh==+hh/ from the target plate thickness becomes zero. There is a relationship between the plate thickness deviation on the entrance side of the rolling machine and the plate thickness deviation on the exit side as shown in equation (1).
, dh ((C11,7□-601,-*(11 section; rolling machine elastic modulus M; rolled material plasticity coefficient The coefficient M varies greatly depending on the temperature of each part of the rolled material, and it is extremely difficult to correct M based on this temperature distribution during piezoelectricity.Therefore, the disadvantage is that the temperature unevenness in the longitudinal direction increases. there were.

On the other hand, BIER Mu・Mu GC changes the thickness of the rolled material.

Although it has an excellent ability to correct hardness fluctuations or plate thickness deviations based on friction coefficients, since it is feedback control, the response is slightly lower than that of IF/MUGC, and the plate thickness deviation due to the eccentricity of the back-up roll. There is a problem that thickness variations are amplified.

- So, in the conventional plate thickness control method, as mentioned above, only one control system is adopted to perform control as effectively as possible.

However, in recent years there has been a growing trend toward energy conservation, and there has been a trend to lower the heating temperature of the piezoelectric material in the heating furnace in thermoelectric lines, resulting in an overall increase in the deformation resistance of the rolled material and the effects of skid marks becoming more noticeable. As it happens, ν
ν・muGC no longer exerts sufficient control effect.

This invention was devised to solve the problems of the conventional methods, such as the first plate thickness control system such as ν1・muGC, and the B
It is an object of the present invention to provide a plate thickness control method that can perform plate thickness control with high precision by effectively utilizing both a second plate thickness control system such as Neem Rum and Mu GC.

The plate thickness control method according to the present invention measures the temperature unevenness in the longitudinal direction of the rolled material immediately after the hot rolling mill, which is a pre-process of the cold rolling mill to be controlled, or before introducing it into the hot rolling mill, and measures the temperature unevenness in the longitudinal direction of the rolled material. When the unevenness is relatively large, the gain of the second plate thickness control system is also lowered than the gain of the first plate thickness control system, and when the temperature unevenness is relatively small, the gain of the control system is t. −
This also increases the gain of the second control system.

Next, an embodiment of the plate thickness control method according to the present invention will be described based on the wJ plane. - In Fig. 1, a rolling mill 2 in a cold steel plate rolling line 1 includes a first plate thickness controller 3 which is ]I'ν・mu GC and a second plate thickness controller 4 which is BXBRmu・AGC. These controllers 3 and 4 are connected to the CPU 5 in parallel. The CPU15K hot-rolls the material 6 to be rolled and receives the temperature unevenness information signal S from the good hot rolling line, and
Based on this signal 8, PU5 adjusts the gain G of controller 3.4.
Set 1%G2. The signal e is obtained by detecting temperature unevenness in the longitudinal direction of the rolled material 6 immediately after hot rolling ξ or before introduction into the thermoelectric mill using a temperature needle such as a radiant temperature needle. A non-contact thickness gauge 7 such as an I-line thickness gauge is arranged on the entry side of the rolling mill 2, and a detection signal from the thickness gauge 7 is input to the controller 3. The control SS controls the rolling mill 2 based on the thickness needle detection signal so that ΔH=Q. The rolling mill 2 comprises a hydraulic cylinder 9 whose pressure is controlled by a servo valve 8, to which a controller 3.4 is connected. The rolling mill 2 is provided with a load cell 10, and the rolling pressure of the rolling mill 2 is detected by the load cell IOK and fed back to the controller 4.

For example, when the temperature unevenness, that is, the hardness unevenness is large, the gain Gl of the first plate thickness controller is reduced, and
Increase the gain G2 of the second plate thickness controller.

As a result, while minimizing the influence of fluctuations in the coefficient M,
It is possible to control plate thickness with high responsiveness and with little influence of eccentricity of the rolling rolls.

When the temperature unevenness, that is, the hardness unevenness is large, K is
Since the influence of the coefficient M is very small, the gain G1 is increased and the gain G2 is decreased. As a result, precise plate thickness control can be performed in a feedforward manner.

Such setting of the gain G1%G2 is performed, for example, as shown in table @1.

When the gain G1%G2 is optimally set in cold rolling, the thickness of the product is %! in the case of a rolled material with relatively large hardness unevenness! As shown in the fi diagram, the accuracy was about ±10 Cμ], and in the case of a rolled material with small hardness unevenness, the accuracy was about ±5 [μ] as shown in FIG. On the other hand, in conventional sheet thickness control methods, sheet thickness deviations of approximately ±1O[μ] occur even for rolled materials with relatively small hardness unevenness, and thickness deviations of ±20[μ] occur for rolled materials with large hardness unevenness. A large deviation close to μ] occurred.

Table 1 As mentioned above, the plate thickness control method according to the present invention suppresses temperature unevenness in the longitudinal direction of the rolled material immediately after the hot rolling mill, which is a process preceding the rolling mill to be controlled, or before introducing it into the thermoelectric mill. When the temperature unevenness is relatively large, the gain of the second control system is increased as well as the gain of the first control system, and when the temperature unevenness is relatively small, the gain of the KFi first control system is increased. The gain of the second control system has also been increased, making effective use of both the first control system such as the PL/MU GC and the second control system such as the B engineering 8R M/MU GC, resulting in a high-precision board. It has an excellent effect of being able to control the thickness.

Note that this invention is not limited to the above embodiments,
Any feedforward control system may be employed as the first control system, and a gauge meter GC control system may be employed as the second control system. Depending on the situation, the gain of one control system may be set to 100 (9G), and the gain of the other control system may be set to O (%).

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the control system in the first embodiment of the plate thickness control method according to the present invention, and Fig. 92 shows the variation in the plate thickness of the product when a rolled material with large temperature unevenness is rolled by the conventional method. Figure 3 is a graph showing the variation in thickness of the product when a rolled material with small temperature unevenness is rolled by the conventional method, and Figure 4 is a graph showing the variation in thickness of the product when rolled material with large temperature unevenness is rolled using the spinning example. FIG. 5 is a graph showing the variation in the thickness of the product when the rolled material with small temperature unevenness is rolled according to the above embodiment. 1...Cold steel plate rolling line, 2...Rolling machine% 3...First plate thickness controller,
4...Second plate thickness controller, 5...CPU16...
Material to be rolled, 7... Thickness gauge, 8... Servo valve, 9... Hydraulic cylinder, lO... Load cell. Agent Tatsuyuki Unuma (and 2 others) 4 Figure 1 10 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] +1) A first plate thickness control system that feedforwardly controls the rolling mill reduction amount based on the plate thickness at the entrance of the cold rolling mill, and feeds back the rolling mill reduction amount based on rolling pressure fluctuations during rolling. In the plate thickness control method of rolling a steel plate to a desired plate thickness while also using a second plate thickness control system of a gauge meter type GC, which controls the thickness of the steel plate, the heat [1
The temperature unevenness in the longitudinal direction of the piezoelectric material is measured immediately after rolling or before it is introduced into the hot rolling mill, and when the temperature unevenness is relatively large, the gain of the second control system is made higher than the gain of the first control system. A sheet thickness control method characterized in that when the temperature unevenness is relatively small, the gain of the first sheet thickness control system is also increased higher than the gain of the second sheet thickness control system.