JPH0970609A - Method and device for controlling compensation of rolling speed in continuous hot rolling mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make tension constant by calculating the change of a friction factor from the actual result rolling load and the forecast load of a rolling stand just before and just after of the supply start and stop of lubricating oil, finding a forward slip change from the change quantity of the function factor, and compensation a rolling speed. SOLUTION: A stock 2 to be rolled is rolled by at least two rolling stands 1-1 and 1-2. Just after biting the stock 2, the actual result rolling loads P1 and P2 of the respective rolling stands 1-1 and 1-2 with no lubricating oil, are measured by a load cell 3. Actual result roll peripheral speeds V1 and P2 are measured. An actual result rolling load P1 , just after supplying the lubricating oil from valves 5-1 and 5-2, is measured. A forecast load P1 in the case of a sticking friction is calculated from a rolling schedule. The rations P1 /p1 and P1 '/p1 of the loads of the actual result and the forecast, are found. From this difference, the change quantity of a friction factor is found, the rate of change of the forward of the stand 1-1 is calculated according to the change quantity, and a speed compensation quantity is found. Even when a rolling state is remarkably changed by the start of a lubricating oil supply, hunching does not generate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of compensating and controlling a rolling speed in a continuous hot rolling mill for plate rolling, and a compensation controller suitable for carrying out the method.

[0002]

2. Description of the Related Art In recent years, in order to save energy in the rolling process and to improve the roll unit consumption by reducing roll flaws, hot lubrication rolling in which lubricating oil (hereinafter referred to as rolling oil) is applied to rolling rolls is often used. In most cases, the rolling oil supply is
In order to ensure that the tip of the material to be rolled is caught in the rolling roll, the supply of the rolling oil is started after entering the steady state without supplying it from the leading edge. In addition, in order to remove the rolling oil that has adhered, it is possible to stop the supply before the tail end of the material to be rolled leaves the rolling stand, print the rolling oil that has adhered to it, or burn it off at the temperature of the material to be rolled. Has been done.

However, according to this method, the frictional state between the material to be rolled and the rolling rolls greatly changes with the start or stop of the supply of rolling oil, and as a result, rolling often becomes unstable. This is because the mass flow (volume velocity) balance of the rolled material passing between the rolling stands is disrupted mainly due to the change of the advance rate and the change of the outlet plate thickness accompanying the change of the friction coefficient. For example, a case where rolling oil is supplied to the rolling stand will be described. In this case, the friction coefficient of the rolling stand decreases, and as a result, the advance rate decreases and the reverse rate increases, as shown in FIG. 2, so that the mass flow of the rolling stand decreases. As a result, excessive tension is generated on the downstream side of the rolling stand, and a phenomenon (loop) occurs in which the material to be rolled has an excess between the rolling stands on the upstream side.

Generally, a looper or a tension control device is provided between rolling stands in order to absorb an unbalance of mass flow. However, as the frictional state changes, these devices alone are used for rolling. It becomes impossible to absorb changes in mass flow between stands, leading to variations in plate thickness and plate width and in extreme cases misrolling. Further, even when the concentration of the rolling oil significantly changes, the same change and the same inconvenience associated therewith are observed.

[0005]

As a typical prior art for dealing with the problems described above, Japanese Patent Publication No. Sho 60-7566.
There is an invention disclosed in Japanese Patent Publication No. JP-A No. 2003-242242, which is a PID of a tension control device according to changes in the amount and concentration of rolling oil.
It is about how to adaptively correct the control gain,
According to this method, the tension between the looper or the stand is promptly stabilized against changes in the rolling oil during rolling. However, since it is not judged whether the gain value to be corrected is stable and does not impair the responsiveness of the system to be controlled, the amount of gain correction may be excessive with respect to the input value of the control system. . In such a case, problems such as hunting of the looper or the tension and deterioration of responsiveness are unavoidable. Therefore, it is considered that there is less risk in the compensation control that directly gives the speed correction amount that cancels the rolling state change, that is, the mass flow change, than the ensuring of the followability by changing the gain of the control system.

Regarding this problem, as a prior art for controlling the rolling speed, there is Japanese Patent Publication No. 59-23887.
According to the present invention, the amount of compensation for the rolling speed is determined with reference to the result of experimentally determining the direct relationship between the amount of change in rolling oil amount and the amount of change in mass flow. However, the amount that has to be compensated for varies greatly depending on the rolling temperature, the type of material to be rolled, the rolling schedule, etc., so even if the direction for compensating the speed (+/-) is correct, it is overcompensated. There is a good chance. Therefore, in order to determine the compensation amount, some actual value of the rolling state amount is necessary, and it cannot be said that the above-mentioned prior art can fundamentally solve the above problems.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a case where the rolling state changes significantly at the time of starting or stopping the supply of rolling oil. It is an object of the present invention to provide a rolling speed compensation control method and apparatus for a continuous hot rolling mill, which can perform stable rolling even if there is any, and can improve product quality.

[0008]

The present invention has the following configuration to achieve the above object. That is, the present invention relates to a continuous hot rolling mill that performs plate rolling by providing at least two rolling stands with means for detecting the rolling load and the circumferential speed of the rolling rolls and an oil supply device that supplies lubricating oil to the rolling rolls. The actual rolling load of the rolling stand immediately before and immediately after the supply of the lubricating oil from the oil supply device to the rolling roll of each rolling stand is started and stopped, and the actual rolling load is detected. And the predicted load previously obtained for the rolling stand, the change in the friction coefficient is calculated, and the rolling speed compensation amount is determined from the change in the advance rate obtained from this friction coefficient change amount. The rolling speed compensation control method is characterized by compensating and controlling the rolling speed of the rolling stand.

The present invention also provides at least two rolling stands, a speed controller for controlling the circumferential speed of the rolling rolls via a roll driving motor, a means for detecting the rolling load and the rolling roll circumferential speed, and the rolling rolls. In a continuous hot rolling mill that performs plate rolling with an oil supply device that supplies lubricating oil to the rolling mill, it corresponds to when the lubricating oil is started and stopped from the lubricating device to the rolling rolls of each rolling stand. From the data collected and calculated by the data collection and calculation means for collecting and calculating the actual rolling load and the rolling roll peripheral velocity detected immediately before and after, and the predicted load previously obtained for the rolling stand. The change in friction coefficient is calculated, and the rolling speed compensation amount is determined from the change in the advanced rate obtained from this friction coefficient change amount, and this rolling speed compensation amount is controlled. As a rolling speed compensation control device in the velocity compensation amount calculating means and a comprise continuous hot rolling mill, characterized in that it is configured to provide a speed control apparatus of the rolling stand.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the embodiments of the accompanying drawings. FIG. 1 is a device block diagram showing a schematic structure of a continuous hot rolling mill according to an embodiment of the present invention. In this figure, 1-1 to 1
-2 is each rolling stand of the continuous hot rolling mill (n = 2), which continuously performs plate rolling on the material 2 to be rolled. 3 is
A load cell provided in each rolling stand 1-1 to 1-2 is provided so as to measure the rolling loads P _{1 to} P ₂ , respectively.
Reference numeral 4 denotes an oil supply device for supplying rolling oil to each of the rolling stands 1-1 and 1-2, which determines the required amount of rolling oil based on the steel type of the rolled material and the surface condition of the roll, and adjusts the flow rate. The rolling oil supplied from the oil supply device 4 is supplied to each rolling roll 7 from each nozzle 6 through each valve 5-1 to 5-2.

The rolling mill is provided with a data collection computer 8, a velocity compensation amount computer 9 and each velocity control device 10. The data collection computer 8 calculates various data during rolling of the material 2 to be rolled, that is, the rolling load P ₁ to
P _2, roll peripheral speed V ₁ ~ of each rolling stand 1-1～1-2
It incorporates an open-close (on-off) signal V ₂ and each valve 5-1～5-2 data collection. The speed compensation amount calculator 9
The speed compensation amounts ΔV _{1 to} ΔV ₂ of the rolling stands 1-1 to _1-2 are calculated based on the data fetched by the data collection computer 8 as described later. The speed control device 10 is provided in each rolling stand 1-1 to _1-2 and controls the roll peripheral speeds V _{1 to} V ₂ via each roll drive motor 11.

Next, the procedure for determining the speed compensation amount in the present invention will be specifically described for the case of supplying rolling oil. When the material 2 to be rolled sequentially bites from the first rolling stand 1-1, each rolling stand 1-1 to 1 immediately after biting
-2 actual rolling load P ₁ ~ P ₂ , actual roll peripheral speed V ₁ ~
V ₂ is measured each time the rolled material 2 passes through each rolling stand, and this is taken in by the data collection computer 8 and collected. At this time, each of the valves 5-1 and 5-2 is in a closed (off) state. Next, immediately after the ON signal is issued to the valve 5-1 to apply the rolling oil to the first rolling stand 1-1, the actual rolling load P _{1 ′} is measured again and collected by the data collection computer 8. To do.

Each collected data is a speed compensation amount calculator 9
Sent to In this computer 9, first, the change in the friction coefficient is calculated from the change in the actual rolling load. The calculation method in this case is as described below.

First, as the predicted load of the first rolling stand 1-1, the load p ₁ in the case of fixed friction (the state in which there is no slippage due to friction) is calculated in advance from the rolling schedule. The rolling schedule is a reduction (thickness) pattern that is determined by the load distribution ratio to each rolling stand in continuous rolling. Generally, the rolling mill capacity (load, torque) and the strip shape after rolling are used. In consideration of the above, the load distribution ratio of each stand is determined in advance, and the inlet and outlet thicknesses of each stand are determined using the power curve. The rolling load of each rolling stand can be obtained from the thus determined rolling reduction amount (thickness reduction amount) at each rolling stand, temperature conditions, and steel type components.

Next, the actual rolling load P₁, P_{1 '}Against each
Ratio P with each predicted load₁/ P₁, P _{1 '}/ P₁Calculate
You. Actual rolling is a mixed friction of sticking and sliding, so
The ratio P / p between the fine rolling load and the predicted load changes due to friction
This is due to the change in the coefficient μ. Figure 3 shows the actual load
The relationship between the load ratio of the weight and the predicted load and the friction coefficient is shown.
However, according to this diagram, when the friction coefficient μ is 0.2, the load
The minimum ratio is 0.7, and the load ratio increases as μ increases.
Increased, and μ = 0.5, the maximum load ratio is about 1.03
ing. Therefore, by using this relationship, the friction
The coefficient change Δμ is obtained by the following equation (1).
However, the relationship in Fig. 3 is related to the operation such as rolling roll diameter and reduction ratio.
The table depends on the operating conditions in advance because it depends on the conditions.
It is necessary to create a rule value or formulate it.

[0016]

[Formula 1] Δμ = (P _{1 ′} / p ₁ ) − (P ₁ / p ₁ ) ... (1)

Next, the speed compensation amount calculator 9 calculates the advance rate change Δf ₁ of the first rolling stand 1-1 with respect to the friction coefficient change amount Δμ obtained by the equation (1). The change of the advanced rate with respect to the change of the friction coefficient can be calculated from the rolling theory, and for example, according to 0R0WAN, it changes as shown in FIG. However, if the theoretical rolling equation is calculated from the beginning, it will take too much time to exert control performance. Therefore, at least the coefficient of influence (δf / δμ) based on the rolling theory should be created as a table value or a mathematical formula should be created. Give it. At this time, the advance rate change Δf ₁ is obtained by the following equation (2).

[0018]

## EQU2 ## Δf ₁ = (δf / δμ) × Δμ (2)

The procedure for calculating the speed compensation amount will be described below. Consider the deviation of the mass flow after application of rolling oil from that before application of rolling oil. The deviation of the mass flow in each rolling stand is expressed by the following equation (3).

[0020]

(Equation 3)

In equation (3), the change in plate thickness in the first term on the right side is that the plate thickness control system is always operating and the response is sufficiently faster than the time from rolling oil application to mass flow change.
It may be h ₁ = 0. Moreover, the change in the advance rate due to the change in plate thickness is extremely small and can be ignored. Therefore, from the formula (3), the mass flow change of each rolling stand in the present rolling can be expressed only by the change of the advance rate, and the rolling speed compensation amount for making the change amount ΔMF zero can be expressed by the following formula (4). Can be expressed as

[0022]

(Equation 4)

The mass flow change can be absorbed by giving the rolling speed compensation amount ΔV ₁ obtained in the above process to the speed control device as a control amount. The description up to now is for the case where the supply of rolling oil is started.On the other hand, when the supply of rolling oil is stopped, the actual rolling load during and immediately after the supply of rolling oil is measured and data is collected. The speed compensation amount can be obtained by the same procedure, and detailed description thereof will be omitted to avoid duplication.

[0024]

EXAMPLE FIG. 4 shows a transition of the looper angle when rolling speed compensation control is performed in a continuous hot rolling mill for steel equipped with a looper mechanism according to an example of the present invention, in comparison with a conventional example. However, as is clear from this figure, it is understood that the implementation of the present invention makes the mass flow between the rolling stands extremely stable both immediately after starting the rolling oil and immediately after stopping the rolling oil.

As described above, by carrying out the present invention, it is possible to perform stable rolling even if the rolling condition changes when the rolling oil is started and stopped. In the above embodiment, 2
Although the present invention is applied to the case of a multi-stage continuous rolling mill, the present invention is not limited to this and the same applies to a multi-stage continuous rolling mill having three or more stages.

[0026]

As described above in detail, according to the present invention, the tension can be kept constant without causing hunting even when the rolling condition is largely changed at the time of starting or stopping the supply of rolling oil. It is possible to perform stable rolling.

[Brief description of drawings]

FIG. 1 is an apparatus block diagram showing a schematic structure of a continuous hot rolling mill according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a delivery side plate thickness and an advance rate with respect to a change in friction coefficient of a rolling mill.

FIG. 3 is a diagram illustrating a relationship between a load ratio of an actual load and a predicted load and a friction coefficient.

FIG. 4 is a diagram showing a transition of a looper angle in a continuous hot rolling mill for steel provided with a looper mechanism in comparison with an example of the present invention and a conventional example.

[Explanation of symbols]

1-1, 2 ... Rolling stand, 2 ... Rolled material,
3 ... Load cell, 4 ... Oil supply device, 5-1, 2 ... Valve,
6 ... Nozzle, 7 ... Rolling roll, 8 ... Data collection calculator, 9 ... Speed compensation amount calculator, 10 ... Speed controller, 11 ... Roll drive motor,

Claims (2)

[Claims] 1. A continuous hot rolling mill for plate rolling, comprising at least two rolling stands, means for detecting a rolling load and a rolling roll peripheral speed, and an oil supply device for supplying a lubricating oil to the rolling rolls. In response to the start and stop of supply of lubricating oil from the oil supply device to the rolling rolls of each rolling stand, the actual rolling load of the rolling stand immediately before and immediately after that is detected, and the actual rolling load is calculated. The change in the friction coefficient is calculated from the predicted load obtained in advance for the rolling stand, and the rolling speed compensation amount is determined from the change in the advance rate obtained from the friction coefficient change amount. A rolling speed compensation control method, characterized by compensatingly controlling a rolling speed of the rolling stand. 2. A speed control device for controlling the peripheral speed of the rolling rolls of at least two rolling stands via a roll driving motor, a means for detecting the rolling load and the rolling roll peripheral speed, and a lubricating oil for the rolling rolls. In a continuous hot rolling mill that performs plate rolling with an oil supply device that supplies oil, immediately before the supply of lubricating oil from the oil supply device to the rolling rolls of each rolling stand is started and stopped,・
Data collection calculation means for collecting and calculating the actual rolling load and rolling roll peripheral speed detected immediately after, and a change in the friction coefficient from the data collected by this data collection calculation means and the predicted load previously obtained for the rolling stand. And calculate
The rolling speed compensation amount is determined from the change of the advanced rate obtained from the friction coefficient change amount, and the rolling speed compensation amount is provided as a control amount to the speed control device of the rolling stand. A rolling speed compensation controller for a continuous hot rolling mill, which is characterized in that: