JPS6150042B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for rolling a plate material using a roll cross method.

In recent years, the requirements for thickness accuracy in the width direction of rolled products have become increasingly strict, and currently this is being addressed by attaching an initial crown to the roll in order to cancel the deflection of the roll due to the rolling load. When rolling conditions such as the width and thickness of the sheet material change, it is necessary to replace the roll with a roll with a different crown, so it is necessary to have rolls with many different types of initial crowns, and the roll Replacement causes a reduction in the operating rate of the rolling mill, and the crown of the roll changes significantly due to roll wear and thermal expansion as the rolling process progresses. There has been a need in the industry for a means to control the thickness distribution of.

As a method for controlling this, the well-known work roll bending method was developed.
Although this method has been effective to some extent, there is a limit to the bending force that can be applied to the work roll due to the strength of the roll neck of the work roll, so it has not been possible to obtain a sufficient ability to modify the thickness distribution in the sheet width direction.

On the other hand, there is a well-known so-called cross-roll rolling technique in which the thickness distribution in the width direction of the sheet is corrected by rolling with the axes of the rolls slightly crossing each other in the horizontal plane. For example, in Japanese Patent Publication No. 54-75456, as shown in Fig. 1, the axes of the upper and lower reinforcing rolls 1 and 2 are crossed in the horizontal plane to roll a plate material, and as shown in Fig. 2, the upper and lower reinforcing rolls are A technique is disclosed in which the axes of the rolls 3 and 4 intersect in a horizontal plane to roll a plate material. Also, Tokukai Akira
No. 55-64908 discloses that the upper work roll 3 and the upper reinforcing roll 1 and the lower work roll 4 and the lower reinforcing roll 2 are kept in a state in which their axes are kept substantially parallel to each other, as shown in Fig. 3a and b. A technique is disclosed in which an upper pair of rolls and a lower pair of rolls are configured, and the axes of the upper and lower pair of rolls intersect in a horizontal plane to roll a plate material. Furthermore, Japanese Patent Publication No. 50-24903 discloses a technique for rolling a plate material by intersecting the axes of upper and lower intermediate rolls 5 and 6 in a horizontal plane, as shown in FIG.

By the way, in the above-mentioned cross-roll rolling, although it is somewhat effective in canceling the deflection of the rolls, which is the original purpose, in general, a so-called thrust force is generated that tries to move the rolls in the axial direction. has been known for a long time. This thrust force can be counteracted by increasing the strength of the mechanical parts that hold the rolls, but the inventors believe that this thrust force can cause the work-side pressure detected by the rolling load detector to increase. It was discovered that there is a drawback that the load and the load on the drive side are different. That is, for example, when the axes of the upper and lower pair of rolls shown in Fig. 3 intersect in a horizontal plane, a thrust force as shown in Fig. 5 acts, and from the balance of force and moment, the following equation (1) is obtained. A rolling force unbalance occurs, ΔP=F・D _W /a... (1) where, ΔP: Size of rolling force unbalance on the work side and drive side F: Between the work roll and the rolled material Thrust force D _W : Work roll diameter a: Distance between the right and left (work side and drive side) rolling support points (shown in Figure 5) Also, the method of crossing only the reinforcing rolls shown in Figure 1 or only the work rolls As a result of investigation, it has become clear that when the .

ΔP=F・D _W /a+F′・D _W +D _B /a……(2) Here, F′: Thrust force between the reinforcing roll and work roll D _B : Diameter of the reinforcing roll Such horizontal rolling force When unbalance occurs, it becomes difficult to control meandering in order to roll the plate straight. Regarding this meandering control, for example,
- No. 88914 describes a situation in which the passing position of the rolled plate is shifted to the left or right (work side or drive side) relative to the roll center or is oblique to the pass center line in a normal 4-high rolling mill. In order to prevent the meandering that occurs when rolling is performed at the A method is disclosed for automatically adjusting the left and right roll openings based on a signal or the like.

However, in cross-roll rolling, even if rolling is performed under normal conditions, an unbalance in the rolling force between the left and right sides occurs, as explained earlier with reference to Figures 5 and 6, so meandering control is not effective. The problem is that it doesn't work.

In response to this problem, the inventors discovered that if four rolling load detectors were installed and the sum of the upper and lower load detection signals was taken, the left and right rolling force imbalance would disappear, and the present invention was created. The gist is that in a roll cross rolling mill, a total of four rolling load detectors are installed between the upper reinforcing roll chock and the upper part of the housing and between the lower reinforcing roll chock and the lower part of the housing on the work side and drive side. By providing a rolling method in which the meandering of the plate material is controlled by adjusting the left and right reduction based on the output signal from the detector, and a rolling machine in which the thrust force generated in the axial direction of the roll is detected by the output signal from the detector. The present invention relates to a rolling method used as an emergency measure signal, and an apparatus for carrying out the method.

The present invention will be explained in more detail below with reference to the drawings.

In this invention, as shown in FIG. 7, the upper side of the rolling mill,
That is, a load cell 22 is provided between the upper reinforcing roll chock 21 and the upper part of the housing (not shown), and a load cell 22 is provided between the upper reinforcing roll chock 21' and the lower part of the housing (not shown).
A hydraulic cylinder 23 and a load cell 22' are arranged between the two, and each load cell detects the load separately. At this time, the magnitude of the load on the lower side may be detected by detecting the pressure of hydraulic oil applied to the roll lowering hydraulic cylinder (FIG. 7, 23). If the loads are P _WT (upper working side), P _DT (upper driving side), P _WB (lower working side), and P _DB (lower driving side), then In the upper roll group, the following equation (3) holds true from the balance of moments around point A.

(P _DT - P _WT )・a/2=F・D _W /2 ∴P _DT − P _WT =F・D _W /a ...(3) Here, P _DT : Size of load on the upper and driving side P _WT : Size of the load on the upper and working side Also, in the lower roll group with respect to the material S, the following equation (4) holds true from the balance of moments around point B.

(P _WB - P _DB )・a/2=F・D _W /2 ∴P _WB − P _DB =F・D _W /a ...(4) Here, P _WB :Lower side and working side load Size P _DB : Size of the load on the lower and drive side Therefore, from the above equations (3) and (4), the following equation (5) can be obtained.

P _WT + P _WB = P _DT + P _DW ...(5) In other words, equation (5) shows that measuring only with the upper load cell or the lower hydraulic cylinder will cause a difference in the left and right loads, but the sum of the upper and lower loads will be This means that the influence of thrust force is removed and the load on the working side and the load on the driving side become equal.

By the way, when determining the relationship between the amount of meandering and the load difference (rolling force imbalance) in a normal 4-high rolling mill, as shown in Figure 8, the amount of meandering is y _c , the load on the working side is P _W , and the load on the driving side is The load is P _D , the difference between both loads is P _df = P _W - P _D , and the rolling load which is the sum of both loads is P
When _n = P _W + P _D , the following equation (6) holds true from the balance of force and moment.

P _df =2/a・P _n・y _c ...(6) Therefore, in roll cross rolling, P _W ,
If we process PD as shown in equation (7) below, we get (6)
The formula holds true as is.

In this way, the signals from the four load detectors are processed and used as shown in equation ( ₇ ) above, and the right _{and left} If the opening degree of the rolls is automatically adjusted, meandering control will work effectively even in cross-roll rolling.

Here, an example of actually automatically controlling meandering based on the load difference ratio r _df will be described using FIG. 8 as an example.

The rolled material S is rolled down by work rolls 3 and 4, and the work rolls 3 and 4 are supported by back-up rolls 1 and 2, respectively. Backup rolls 1 and 2 via a reduction screw (not shown)
The load applied to is detected by upper, lower, left and right load detectors 8, 8', 9, 9'. Detected load signals P〓 _WB , P〓 _WT , P〓 _DB , P〓 _DT
is arithmetic unit 1
sent to 0, After is obtained, the load difference ratio r〓 _df r〓 _df = P〓 _df /P〓 _n = (P〓 _W − P〓 _D ) / (P〓 _W + P〓 _D )……(9
) is required.

The results of this calculation are input to a proportional calculator 11 and a differential calculator 12, and the proportional operation signal and the differential operation signal from these calculators are added together in an adder 13. The signal S _df from the adder 13 is sent to the left and right roll position setters 6 and 7 via the roll position controller 14, and the left and right roll openings are adjusted in accordance with the meandering amount _yc . For example, when the rolled material shifts toward the operation side, the roll opening on the operation side is decreased in accordance with the load difference rate r _df and its rate of change over time, and at the same time, the roll opening on the drive side is increased by the same amount. The gains of the proportional calculator and the differential calculator can be changed according to the rolling conditions, and in this embodiment, they are configured so that the values calculated by a calculator (not shown) are automatically set. do. In this example, the relationship with the average plate thickness control system has been omitted, but while the average plate thickness control involves controlling the roll openings on both sides by the same amount in the same direction, meandering control Control an equal amount in the opposite direction. In reality, both plate thickness control and meandering control may be performed at the same time, but in this case, the respective roll openings on the operation side and drive side are input to the roll position setting devices 6 and 7 as the sum of both control signals. You can control it by

The proportional calculation adjusts the left and right roll openings in proportion to meandering, and is a basic calculation that can also be found in other controls such as sheet thickness feedback control. The reason for performing differential calculation is that when the control end to correct meandering is adjusting the left and right roll opening degrees, simply controlling proportional to the amount of meandering is insufficient. Although a separate patent application has been filed for this invention, it has no essential relation to the present invention, so its explanation will be omitted.

By the way, it is known that in roll cross rolling, a large thrust force is generated in the axial direction of the rolls. Although this thrust force is not shown,
First, it is applied to the thrust bearing built into the roll chock, and finally it is received by the housing post. However, if the thrust force becomes excessive due to the rolling conditions and exceeds the thrust force allowed by the thrust bearing, the thrust bearing will burn out. Accidents may occur.

Thrust force is normally detected by a load cell for thrust force measurement, and as an emergency measure in rolling operations, when the thrust force exceeds a certain value, the operator manually operates to determine when to open the roll gap to reduce the thrust force. It is used as a reference or as a control signal to automatically open the roll gap when the thrust force exceeds a certain value. However, this type of measuring instrument sometimes fails. For this reason, it is desirable to have a device that can detect double or triple thrust force.

If a total of four load cells are installed above and below the work side and drive side, the following equation (10) can be obtained from the above equations (3) and (4), but (P _DT +P _WB ) - (P _WT +P _DB ) =2・F・D _W /a ∴F=a/2・D _W {( _PDT + PWB) − (P _WT + P _DB )} ...(10) This formula (10) is This shows that the thrust force can be detected by calculating the output signal.

Therefore, as an output signal for emergency measures, the thrust force detected by the thrust force measurement load cell,
The output signals of the four load cells are compared with the thrust force determined by equation (10) above, and the larger thrust force is taken as the true thrust force. When the value exceeds the certain value, the above-mentioned Safety will be improved if the system behaves like this.

In this way, by providing a total of four load cells between the upper reinforcing roll chock and the upper part of the housing and between the lower reinforcing roll chock and the lower part of the housing on the working side and the driving side, meandering control can be performed effectively. In addition to obtaining the desired thickness distribution in the plate thickness direction, thrust force can be detected, failures of the rolling mill can be prevented, and safety is improved.

[Brief explanation of the drawing]

FIGS. 1 to 4 are explanatory diagrams of the conventionally known roll cross rolling method, FIGS. 5 and 6 are explanatory diagrams of occurrence of rolling force imbalance, and FIGS. 7 and 8 are explanatory diagrams of the present invention. be. 1, 2... Reinforcement roll, 3, 4... Work roll, S... Rolled material, 5, 6... Intermediate roll, a...
...Distance between reinforcement roll support points, P...Rolling load, Δ
P... Load difference (rolling force unbalance), D _W ... Work roll diameter, D _B ... Reinforcement roll diameter, F... Thrust force between material and roll, F'... Thrust force between rolls, P _WT ...Load on the upper working side, P _DT ...Load on the upper driving side, P _WB ...Load on the lower working side, P _DB ...
Load on lower drive side, b... Plate width, y _c ... Off-center amount, 7, 7'... Drop position setting device, 8, 8',
9, 9'...Load detector, 10...Calculator, 11
... Proportional calculator, 12... Differential calculator, 13...
Adder, 14... Lowering position controller.

Claims (1)

[Claims] 1. When rolling a plate material using a roll cross rolling device that performs rolling by intersecting the roll axes at an arbitrary angle in a plane parallel to the progressing surface of the rolled material, the work side and drive side The meandering of the plate material is controlled by adjusting the rolling reduction in the left and right directions based on output signals from four rolling load detection means provided between the upper reinforcing roll chock and the upper part of the housing and between the lower reinforcing roll chock and the lower part of the housing. Characteristic roll cross rolling method. 2. When rolling a plate material using a roll cross rolling device that performs rolling by intersecting the roll axes at an arbitrary angle in a plane parallel to the progressing surface of the rolled material, the upper reinforcing roll chock on the work side and drive side and the upper part of the housing. The magnitude of the thrust force generated in the axial direction of the roll is calculated based on the output signals from the four rolling load detection means installed between the lower reinforcing roll chock and the lower part of the housing, and the calculated thrust force is calculated. A roll cross rolling method characterized in that the roll opening degree is increased when the size of the roll exceeds a range allowable for equipment maintenance of the rolling mill. 3. In a roll cross rolling mill that performs rolling by intersecting the roll axes at an arbitrary angle in a plane parallel to the rolling surface of the rolled material, there is a gap between the upper reinforcing roll chock and the upper part of the housing on the work side and drive side, and between the lower reinforcing roll chock. A total of four rolling load detection means are provided between the housing and the lower part of the housing, and the output signals from these four rolling load detection means are input to calculate the meandering amount of the rolled material or the thrust force in the roll axis direction. A roll cross rolling device comprising: an arithmetic device for calculation; and a means for adjusting the rolling reduction on the driving side and the work side of the rolling mill or a means for adjusting the roll opening degree based on the arithmetic results from the arithmetic device. .