JPS59178113A - Method for controlling tandem rolling mill - Google Patents

Abstract

PURPOSE:To maintain stable rolling even when a size changing point moves through plural stands by controlling the stands by the ratios of roll peripheral speeds of respective patterns basing on the position of size changing point, in changing a pass schedule while rolling is operated. CONSTITUTION:Until a starting point X of size changing arrives at an optical (i)th stand (Si); the 1st pattern of the ratios of roll peripheral speeds between respective stands, necessary for maintaining the whole tension between the Si and the (i+1)th stand (S(i+1)) just before the point X arrives at the Si, is operated. Next, basing on the ratios of roll peripheral speeds between respective stands at the time when the point X arrives at the S(i+1), the 2nd pattern of the ratios of roll peripheral speeds between respective stand is operated so as to make the whole tension between the Si and the S(i+1) attain the target value after changing the roll schedule at the time when the finishing point Y of size changing passes the S(i+1). Until the point X arrives at the S(i+1) after arriving at the Si, the Si the S(i+1) is controlled by the ratio of roll peripheral speed of the 1st pattern in accordance with the position of point X. After the point X arrives at the S(i+1), the control is performed in the same manner by the ratio of peripheral speed of the 2nd pattern.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a tandem rolling mill control method, and particularly to a tandem rolling mill in which a plurality of stands are arranged in series to roll a metal strip, the bus scheduler is controlled during rolling. The present invention relates to a tandem rolling mill control method suitable for reducing tension fluctuations and reducing troubles and off-gauge amounts when changing the roll.

[Technical background of the invention]

In recent years, various rolling mill control methods have been developed to change the bus schedule during rolling without stopping the rolling mill in order to improve productivity or quality in rolling mill plants. Now it will be implemented.

For example, in the method shown in Patent Publications Showa Y, G, No. 17/GJ, when a stand with a size change point is reached, the roll gap setting value of that stand is changed to the changed pass schedule. At the same time as changing to the corresponding value,
The speed of all stands on the exit side or the entrance side including the stand is changed to I/' while keeping the ratio constant.

on the other hand,! In the method shown in I'♀ Official Publication Showa B, No. 1/23, when the size change point reaches the i stand, the i Should I change the speed of the stand and at the same time set the exit side of the i-stand to the changed thickness? Change the knob and resize the point force (i+/) when you reach the stand (
Change the speed of the upstream stand including the i stand based on the speed of the i+/) stand to maintain the speed ratio after the change,
At the same time, after changing the roll gap of i-stand
Change the value to correspond to the file.

When applying these conventional methods, the condition is that the length of the material required for size change is shorter than the distance between the stands.

That is, as shown in the explanatory diagram of FIG.
The reason for the roll gap is that when the speed change is completed, that is, when the size change end point Y passes the i stand Si, the size change start point X changes to (i+l) stand S(t
If a change is to be made that will not reach +g, the conventional method described above is effective.

[Problems with background technology]

However, as shown in the explanatory diagram of FIG. 2, the size change starts before the roll gap or speed change of i-stand S1 is completed, and the end point Y of the slack change has not yet reached i-stand Si. Point X is (i+/) stand S
Reach (i+1), (i+/) stand S(1+1)
According to the conventional method, if the roll gap or speed of
1) The mass flow balance between the two is disrupted and tension fluctuations occur.

For example, according to the former method of the conventional method, when the size change starting point X reaches (i) - /) stand S (1 torl) as shown in Fig. ) Stand S
Schedule after changing the roll gap of (i+1) = -R (
Hereafter, the speed of i-stand S1 is changed to V'i as shown in equation (1).
Change to

Here, Vl is the roll peripheral speed of the i stand, V1+1 is the roll peripheral speed of the (i-1-/) stand, the subscript A is the value of the schedule before change (hereinafter referred to as the A schedule), and the subscript B is the value of the schedule before change. This is the value of the schedule.

Here, equation (1) is the mass flow constant law at the time when all stands are changed to schedule B. Equation (2) is the constant law of mass flow. , and the size change point is (l+)) stand S(i+1)
From equation (3) of the constant mass flow law when reaching , (2
) and (3) are equivalent, and it is assumed that the outlet side plate thickness of i-stand S1 is equal to the value of the B scale rule, which is B. However, as shown in Fig. 2 When the i-stand Si is in the process of being changed, as in
If the roll gaps or speeds of both stands are changed at the same time, the balance of the mass 70 will be lost and tension fluctuations will occur.

In addition, in cases such as hot strip finishing mills where the line speed cannot be changed arbitrarily due to the need to maintain the material temperature, or cases such as the one shown in Figure 1 due to the limited response of the rolling control device and speed control device, This could easily occur and there was a strong demand for effective solutions.

[Object of the Invention] Therefore, the object of the present invention is to solve the problems of the prior art and to provide a tandem rolling mill control method according to d), which makes it possible to change the pass schedule stably and accurately. It is in.

[Summary of the invention]

In order to achieve the above object, the present invention is arranged so that when changing the rolling schedule while continuously rolling a material by arranging a plurality of rolling stands in series, the change starting point is at any i-stand. After reaching the (i + /) stand, first change between each stand in order to maintain the full tension between the i stand and (i + /) stand immediately before the change start point reaches the i stand. The first pattern of the roll circumferential speed ratio of At the point when the total tension between the i stand and the (i+/) stand becomes the target value after changing the rolling schedule, the first change in the roll circumferential speed IW ratio is made to change the roll circumferential speed ratio between each stand. After the change start point reaches the i stand, (i+
/) While reaching the stand, control the i-stand or (i-+-/) stand with the roll circumferential speed ratio of the first pattern according to the change start point 1, and change the start point but(
This invention provides a tandem rolling mill control method for controlling the i-stand or (i+/) stand with the roll circumferential speed ratio of the first pattern depending on the change start point position after reaching the i+/) stand. .

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings together with an explanation of its principles.

Any i stand of v-1 tandem rolling mill (i 10))
Think about the stand. When changing the size during rolling, one of the following cases can be considered as the rolling state.

The first is the state from when the size change start point reaches 1 stand until the size change start point reaches the (i+l) stand, and the first is the state from when the size change start point reaches the (i+/) stand. This is the state from when the size change end point passes the (i+/) stand.

In the present invention, for these λ rolling states, the stand distance is 9J.
This method achieves a method of changing the pass schedule by reducing G force fluctuations to maintain stable rolling operation and reducing off-gauge length. In other words, in the first rolling state, the i-stand front tension, That is, the roll circumferential speed of the i stand is controlled so as to maintain the rear tension of the (i+/) stand at the value of the A scale, and the fluctuation of the rear tension of the (i+/) stand, which is especially noticeable in hot strip mill finishing rolling mills, is This makes it possible to prevent (i+/) changes in the width of the stand exit side and (i+l) changes in the thickness of the stand exit side.

Too bad, in the first rolling state, the i-stand front tension, i.e., (i+/) stand rear tension, quickly shifts to the value of the B schedule, and the change ends from the change opening point X as shown in Figure 1. Even when a plurality of stands exist between points Y, it is possible to stably change the pass schedule.

That is, in the present invention, the fact that it is possible to control the tension between two stands by controlling the roll circumferential speed ratio of two adjacent λ stands to a predetermined value can be used to change the running spool. A predetermined purpose is achieved by applying the above-mentioned λ rolling states to the roll circumferential speed ratio change pattern between each stand of i and (i+/) in advance, and changing the roll circumferential speed ratio according to the transition of the size change point. Achieved.

FIG. 3 is an explanatory diagram of a tandem rolling mill control method according to an embodiment of the present invention, especially the relationship between the rolling state, roll gap setting value, and roll circumferential speed setting value when the size change point does not extend to multiple stands. This shows that.

In Fig. 3(a), the size change point is located upstream of i-stand SL, i-stand SL, (i+/) stand s(1+1
) Skageel before changing Kasaisu (A scale, -le)
This shows the state in which rolling is being performed. In the same figure, hiA, n
fil+LA is exit plate thickness, TENiA is total tension, 5o
I.A.

Sol+IA is Roll Gyakupu, ViAt Vl+IA
are the roll circumferential speeds, respectively.

FIG. 3(b) shows the rolling state immediately after the size change end point Y passes through the i-stand Sl. At this time, the size change starting point X(i+/) has not reached the stand S(l+1). Therefore (i+/) stand S (eye 1)
In order to maintain the exit side plate thickness at hl+1, it is necessary to maintain the total tension between l stand Si + (1+') and stand S(1+1) at TENI. On the other hand, it is necessary to roll so that the i-stand 81 comes out (the i111 plate thickness is 111 at this point of the B schedule. In other words, when the size change starting point X reaches the l-stand Si Start changing the roll gap of i stand S1 from , and reach the size change end point YfJ''-i
When passing through stand S1, the thickness of the exit side plate of l stand Si decreases, and the roll gear setting value S becomes. ■Complete the change.

At the same time, the size change starting point Stand Si and (i+/) Stand S
The change to the roll circumferential speed vl 1 is completed so that the total tension between (i→, 1) is maintained at TENIA.

Fig. 3(c) shows the rolling state immediately after the size change end point Y passes through the (i+/) stand S (1+1n). (i+/) The exit side 1 plate thickness of stand S (eye, 1) is set to the plate thickness 11t+1 of B scale wheel, and between (i+/) stand S(1+g and (i+J) stand S(t+2) In order to maintain the total tension at the A schedule value TgNl+1, the roll gap is set to S.l+1, and the roll circumferential speed is set to V.
i+1. The change to l is completed.

At this time, l stand Si and (i+/) stand S(1
+1) The total tension between the two must be the value of the B scale TENl. In other words, the resizing starting point X is (
The change in the roll circumferential speed of l-stand Si starts from the time it reaches i+/) stand S(1+1), and when the size change end point Y passes through (i+/) stand S(l+1), l-stand Si and (i+ /) The total tension between the stands S(1+1) is completely changed to the roll circumferential speed vl 2 which becomes the value of the B scheduler TENI.

Figure ≠ shows the roll gap of l stand Si in Fig. 3 and l stand Si and (i +)) stand S (l
+1) """ Peripheral speed K ratio (v/V1 +1
) Nohen J'' turn.In the same figure,
1. is the length of the exit side of the i-stand after the size change starting point X reaches the i-stand, and 'xi is the length of the month of the exit side of the i-stand required for size change.

As shown in the figure, in this embodiment, the roll gap is changed from the A scale set value to the B scale set value in accordance with the exit side material length lx required to change the size of the l stand Si. On the other hand, regarding the roll circumferential speed, l stand S
The same roll speed ratio between i and (i+/) stand S(1+1) is set to the exit side interest length 1x required to change the i stand SiO size.
After the size change starting point X reaches (i + l) stand S (1 + 1), the exit side material length required to change the size of (i + /) stand S (1 + 1) is 1xi + 1.
Change accordingly. Here, the roll gap setting value S.

i and roll peripheral speed ratio (Vl, ”/'vl+LA)
, (■L2/V++0.t), etc. can be easily determined in advance.

Figure 3 shows how to change the roll gear knob and call circumferential speed ratio when the size change points span multiple stands.

Here, the change in roll gap is the same as in the case of Fig.

On the other hand, the roll peripheral speed ratio is calculated from the time when the size change start point reaches l stand Si (■lp 1/Vi+iA)
, but before the change is completed, the size change starting point
reaches (i+/) stand S(1+1), so at this point i stand S and (i+/) stand S(1+
It is no longer necessary to maintain the total tension between g at the A scale value TENi. Therefore, as shown by the solid line in Fig. 5, the peripheral speed ratio of the color roll at this point is
).

The changes in the roll gap and roll circumferential speed ratio have been described above, and the roll circumferential speed reference vl REF given to the speed control means of the main engine is calculated by the following equation (4).

Figure 5 is a block diagram showing an example of a control device used to realize the tandem rolling mill control method of this embodiment.
) shows the calculation circuit for the roll gear knob setting value and roll peripheral speed standard. In the same configuration, gate/~3
The circuit is closed at the timing when the size change starting point X reaches the stand. Integrator 4'~B are each stand SI F
S(1+1) p Integrate the roll peripheral speed of S(1+2) and calculate each stand Sip S(1+IJ, S(1+2)
The output side material length h, 114-1111+2, is calculated and output. State determination circuit 7. I has the function of detecting that the size change starting point X has reached the next stand and operating the gate controller 3. Roll gap setting value calculation device 2~
// is each stand "l p S(1+l) y S(1
It has the function of calculating and setting the roll gap from the output material length 1514+4.11-+-z of +2), and the length of each stand exit material required for size change 'ip li+1
The relationship between +11+2 and the roll gap setting price is set in advance. On the other hand, roll circumferential speed ratio calculation device/2.
/3 has the function of calculating the roll circumferential speed ratio, and the relationship between the length of the material on the outlet side of the stand and the next stand required for size change and the roll circumferential speed ratio is set in advance. Multiplier/
μ, /3 has the function of multiplying the output of the roll circumferential speed ratio calculation device /, :l, /3 by the next stand roll circumferential speed reference to generate the roll circumferential speed reference for the stand.

In this configuration, when the size change start point X of the cabinet reaches the i-stand Si, the current value Vl of the roll peripheral speed of the closed circuit Li stand is manually inputted to the integrator ≠, and the size change start point X is determined from the integrator G. The L stand exit side material length 11 after reaching 7 is output. The roll gap setting value calculation device calculates the i-stand roll gap setting value S according to the i-stand roll gap change pattern that is preset according to the l-stand exit side material length 11, which is a human signal. l is output to an i-stand lowering position control device (not shown).

Similarly, the roll circumferential speed ratio calculating device /, 2 is an input signal i-stand exit side material length 1. According to the roll circumferential speed ratio changing pattern set in advance according to
l/vI+1) is output to the multiplier/whatever. At the loss calculator/Hiro, the output of the multiplier/S is (i+l) stand roll circumferential speed standard Vi+1. The product with REF is calculated, and the i-stand roll circumferential speed reference VI REF is output to the i-stand speed control device (not shown in the figure) Material length 11
is i stand Si and (i+i) stand S(1+1)
The gate l is closed when the value becomes equal to or greater than the distance between them, that is, when the size change starting point X reaches the (i+/) stand S(1+1). As a result, the integrator j has (i
+l) The circumferential speed of the stand roll Vi+1 is manually applied, and the length 11+1 of the material on the exit side of the stand (i+/) from the time when the size change start point X reaches the (i+/) stand S(l+1) is calculated and output. Roll gear set value calculation device ff11
0 is a human signal (i+/) Stand exit side material length 11+
(i + /) stand S (1
+x) according to the roll gap change pattern of (i+/
) Stand roll gap setting value S. It outputs i point 1 to 'w (i-+-7) stand lowering position control device (not shown).

Roll peripheral speed ratio calculation device f/:1. determines that the size change starting point t-/) i-stand s1 and (i-1-/) according to stand exit side material length 1i+1
Stand S (l+g) mouth A411 speed ratio ("i/Vt+
1) ti'i<1lli'1 and output to multiplier/l.

Similarly, the roll circumferential speed ratio calculation device /3 is an input signal <
i + l) According to the stand exit side material length 11 + 1 (i + l))
Stand S(i+1) and (i+,z) stand S(1+
The roll circumferential speed ratio (vl +1/vi+2) of 2) is output to the multiplier/S according to a preset change pattern.

Multiplier/S is the roll peripheral speed ratio (■l+1ZvI1,200)
(i+, 2) Stand roll circumferential speed reference Vi+2 R
The product with EF is calculated, (i +)) stunt roll circumferential speed + W reference Vi + 1. REF is output to an (i+l) stand speed control device (not shown).

The state discrimination circuit r is an integrator! The output of (i+l) stand exit side material length 11+1 is (i+/)x stand S(++i
) Gate 3 at the point when the distance between stand 1 of (i+-2) stand S(1+2) is greater than or equal to the distance between stand 1, that is, when the size change starting point X reaches (i+, 2) stand S(1+2). Close the circuit. From this K, the integrator B has (i
-+-The stand roll circumferential speed current value Vl +2 is input, and the size change start point X is (i+8 stand S(i→
-2) (i+u) stand exit IN from the time it reaches
]1 material length 11-1-2 is calculated. The roll gap setting value calculation device // is a human signal <++2) According to the roll gap change pattern of (i+, 2) stand S (1 + 2) which is preset according to the stand Toshinaga 1 and the village (i-1) , 2) Stand roll gap setting value S.

++2 is output to an I/-1 (i-1-, 2) stand lowering position control device (not shown).

In addition, the roll circumferential speed ratio calculation device 13 determines the size change starting point X.
It is judged from the output signal of the state discrimination circuit g that < i-+-z ) has reached the stand S (++2), and after the timing of , the output of the integrator O is (i-4-z) stand 1 ] According to the side material length 11 + 2 (i 10)) Stand S
The roll circumferential speed ratio (vI+''/VI+2) of (1+1) and (i10,2) stand S(1+2) is calculated and output to the multiplier /!;

In addition, in the above embodiment, a method using the downstream stand as a reference is exemplified as a method for changing the roll circumferential speed, but the roll circumferential speed of the downstream stand may be changed using the upstream stand as a reference, and the same effect can be obtained. It is something that can be done.

〔Effect of the invention〕

As described above, according to the present invention, even if the size change point is spread over multiple stands and the roll gap and roll circumferential speed are changed at the same time in multiple stands, it is possible to ensure a constant mass flow between each stand. This is a new tandem rolling mill that can effectively improve productivity and yield by making it possible to change the rolling schedule with stable rolling without fluctuations in tension between stands. It is possible to realize a control method.

[Brief explanation of drawings]

1, FIG. 1 is an explanatory diagram showing an example of plate thickness change, FIG. 3 is an explanatory diagram of a tandem rolling mill control method according to an embodiment of the present invention, and FIG. , an explanatory diagram showing a change pattern of the roll circumferential speed, FIG. 5 is an explanatory diagram showing a change pattern when the plate thickness change points span multiple stands, and a second figure shows the tandem rolling mill control method of the embodiment of FIG. 3. FIG. 2 is a block diagram showing an example of a control device used to realize the system. Si+ S(++1)...Stand, l~3...Gate, Hiro~t...Integrator, 7. f...Status determination circuit, 7~//...Roll gap setting value calculation device, /U,/3...Roll circumferential speed ratio calculation device, /! , /3・
...Multiplier applicant Kiyoshi Inomata 1st
Figure 2 Figure 3 soi', So++ffi Figure 4

Claims (1)

[Claims] When changing the rolling schedule while continuously rolling a material by arranging multiple rolling stands in series, first change the starting point while the rolling schedule reaches an arbitrary stand. The first pattern of the roll circumferential speed ratio between each stand is calculated to maintain the total tension between the l stand and the (i+/) stand immediately before the change reaches the l stand, and then the change starting point is (i -1-/) From the roll peripheral speed ratio between each stand when reaching the stand, the change end point is (i
+l) stand and (i+/
) Calculate the first turn of the roll circumferential speed ratio to change the roll circumferential speed ratio between each stand so that the total tension between the stands becomes the target value after changing the rolling schedule,
From when the change start point reaches the l stand until it reaches the (i) stand, the first
l stand or (i +
/) Control the stand, and after the change start point reaches the (i+/) stand, control the l stand or (i+)) stand with the roll peripheral speed ratio of the second pattern according to the change start point position. Tandem rolling mill control method 0 characterized by