JPH0117761B2 - - Google Patents

Description

[Detailed description of the invention]

This invention changes the rolling position and rolling speed while rolling one material to be rolled in a continuous rolling mill, and
The present invention relates to a rolling control method for rolling with varying plate thickness during running to obtain a rolled material having a product size of 1,000 yen or more. Rolling with varying plate thickness while running has a great effect on improving yield and operational efficiency in high-mix, low-volume production. The present invention can improve product dimensional accuracy in rolling with varying plate thickness during running, and can dramatically increase the economic effects of the above technology. Conventionally announced technologies for rolling by changing the product thickness during rolling (for example, Japanese Patent Publication No. 47-
According to 2018 Publication or Japanese Unexamined Patent Publication No. 51-134357), rolling control is performed as follows.
Now, assume that the product board thickness before the board thickness change is h ^A _F and the product board thickness after the board thickness change is h ^B _F. In this case, when rolling, the same rolling mill model is used in advance to roll products A and B.
The rolling mill rolling reduction set values and rolling speed set values {S ^A _i , V ^A _i }, {S ^B _i , V ^B _i } (i = 1 to N, N is the number of stands) for the product are calculated using a rolling mill control calculator. Calculate and find. First, in order to obtain product A, the rolling mill's rolling position and rolling speed are set to {S ^A , V ^A } calculated by the rolling mill control computer and rolled to a predetermined length. At the appropriate timing when the change point passes through each stand, the set values of each stand are transferred to {S ^B , V ^B } calculated by the rolling mill control computer, and the B product is rolled. By the way, when applying rolling reduction setting values and rolling speed setting values calculated using a rolling mill model by a rolling mill control computer in actual rolling, uncertainties existing in the model formula or rolling data used for calculation Due to the difference between the (base material dimensions, temperature, and steel type constants) and the actual values, rolling cannot be carried out with a satisfactory product dimension accuracy. As a result, off-gauge plate thickness, excessive loops, and excessive tension may occur. For this reason, the above-mentioned rolling reduction setting value and rolling speed setting value are subject to learning correction based on the results of learning the control effect based on the past rolling results of the same material by the rolling mill, and After biting
Rolling in which the initial target product dimensions can only be obtained in a stable state after corrections are made using various control functions such as AGC (automatic thickness control), or some manual corrections are made based on the operator's judgment based on the degree of heating of the rolled material, etc. will be done. Now, regarding products A and B, which have the same base material and rolling mill constants, such as rolling mill rigidity, roll radius, etc., but differ only in product plate thickness designation and rolling temperature designation,
The results of calculating the rolling mill rolling position setting and rolling speed setting are shown in Fig. 1 as {S ^A }, {V ^A } and {S ^B }, {V ^B }. First, in order to correct any errors included in the above settings {S ^A }, {V ^A } for product A before the plate thickness change, learning correction based on the results of rolling the same material before the material rolling or manual correction by the operator is applied. The set values are set as {S ^A1 }, {V ^A1 }, and corrections are made by the rolling mill controller (thickness/width control, temperature/tension value control, looper control, etc.) during rolling after the material is bitten. The set value after being added is {S ^A2 }, {V ^A2 }
It is shown in Figure 2 as follows. The dimensional accuracy and operational stability of product A rolling are determined by the set values {S ^A }, {V ^A1 } with learning correction and manual correction, based on the results of setting calculations, {S ^A }, {V ^A }, etc.
It is reasonable to say that it is better to do so. On the other hand, when it is considered that the learning corrections and manual corrections made before product A was bitten are caused by inherent errors between the material and the calculation function of each setting value made in advance using a rolling model. , Similar corrections are also effective for the calculation results of each setting value applied to B product, and rolling with calculation results {S ^B }, {V ^B } is better than rolling with similar corrections. Obtain rolling results. In other words, when changing the plate thickness to product B after rolling product A, the setting value for changing the rolling position is set for each stand as S ^{B *} _i = S ^B _i + (S ^A1 _i - ^{S A} _i ) (i = 1 to N ) (1) Alternatively, by using an appropriate correction gain αi and setting S ^B* _i = S ^B _i + αi (S ^A1 _i − S ^A _i ) (i = 1 to N) (2), The learned correction and manual correction made are effective for both A product and B product before and after the plate thickness change. Additionally, the following changes will be made to the rolling speed settings. V ^B* _i =V ^B _i +βi (V ^A1 _i −V ^A _i ) (i=1 to N) (3) βi is an appropriate correction gain at each stand. Next, during the rolling of Product A, depending on the results of various control operations regarding intra-plate fluctuations in rolling conditions or the insufficient portions of the above correction, Product A at the point immediately before the plate thickness change point is changed. With normal rolling mill control, rolling is performed with sufficient accuracy and stability, and rolling is much better than when no control operation is performed after biting. Therefore, following the results of these control operations performed during rolling of product A, the target for changing the rolling position when changing the plate thickness to product B is determined as follows. S ^B* _i =S ^B _i +γi (S ^A2 _i −S ^A _i ) (i=1 to N) (4) γi is an appropriate correction gain for each stand, and is used to smooth out the control effect due to correction. The rolling speed setting is also changed to V ^B* _i =V ^B _i +δi (V ^A2 _i −V ^A _i ) (i=1 to N) (5) with the correction gain as δi. As a result, based on the effect of control corrections made for various error factors and disturbance factors in the rolling of Product A, the results of rolling accuracy of Product A immediately before the plate thickness change point are inherited to the rolling of Product B, resulting in stable rolling. By changing the plate thickness in this state, product B can already be rolled with sufficient dimensional accuracy immediately after the change. All of the error factors included in the set values {S ^B }, {V ^B } calculated using the rolling model for B product rolling are
The set values {S ^A } and {V ^A } are the same as those for Product A, and all of the control results during rolling of Product A and the learning effects made over the preceding material are the corrected set values { S ^A2 } and {V ^A2 }, the gist and effects of the present invention are obvious. Furthermore, after the change, all rolling mill controls (thickness and
It goes without saying that good dimensional accuracy and rolling condition can be maintained over the entire length of Product B by reactivating the functions (plate width control, temperature/tension control, looper control, etc.). FIG. 4 shows a block diagram of an example of a rolling control device to which the present invention is applied. Devices 2 to 6, 8, and 9 show normal hot rolling mill devices and functions, and 1
2 is a rolling material, 2 is a rolling roll, 3 is a mill drive motor, and 4 and 5 are devices for determining the speed of each stand rolling roll. 6 is a lowering position control device. Also, 8
is a looper and its position control device, 9 is a successive speed control function unit, and 7 is a rolling control calculation function unit, which determines the thickness change point on the plate material and changes the screw rolling position at each stand as part of the normal mill control function. A command {S} and a speed change command {V} are output to perform sheet thickness change rolling control. The rolling control calculation function unit 7 calculates the rolling position setting value calculated using the rolling model when rolling product A.
S ^A _i to the rolling position control device 6, rolling speed set value V ^A _i
is given as a set value to the devices 4 and 5 to perform rolling control. In addition, the rolling control calculation function section 7 introduces the manual correction amount by the operator and the correction amount by the control function during rolling of product A, and calculates equations (4) and (5) when rolling product B. , by giving set values to the rolling position control device 6 and the devices 4 and 5, respectively, to perform strip thickness change rolling during running. Table 1 shows an example of each set value before and after the change in a 6-stand continuous rolling mill.

[Table] Figure 5 also shows before and after the plate thickness change (plate thickness change rate 2.15
→2.50%, 16.3%) and variation in tension between stands compared with the conventional method. The figure clearly shows the effectiveness of the present invention. As described above, the present invention is effective in expanding the accuracy limit of the rolling position and rolling speed setting calculation function in plate thickness change rolling in a continuous rolling mill, and ensuring sufficient product accuracy and operational stability. It provides essential technology. The above embodiments have been described with respect to rolling while changing plate thickness, but it is also applicable to rolling for changing the width of a product plate or changing the width of a plate during rolling of a plate in a continuous rolling mill equipped with a width control mechanism. Setting value correction based on the same principle is also effective when changing the plate thickness at the same time.Furthermore, regarding the setting of cooling water injection amount made for temperature control, various corrections made for rolling of A product can be applied to the setting value for B product. Additions to changes can have equally great effects.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of the rolling speed setting calculation for the rolling position for products A and B, and Figure 2 is the setting calculation result for rolling product A {S ^A , V ^A } and the correction result before biting {S ^A1 , V ^A1 } and ^the result of setting value correction {S ^A2 , V ^A2 } at the final point ^of rolling of product A. FIG. Fig. 4 is a block diagram showing an example of ^a rolling control device to which the present invention is applied, and Fig ^. 5 shows the rolling reduction before and after changing the plate thickness. , is a diagram showing tension fluctuation. In the figure, 1 is a rolled material, 2 is a rolling roll, 3 is a mill drive motor, 4, 5 is a device for determining the speed of each stand rolling roll, 6 is a rolling position control device, 8 is a looper and its position control device, 9 is a The successive speed control function section is a rolling control calculation function section indicated by 7.

Claims (1)

[Claims] 1. While rolling one material to be rolled, the rolling position and rolling speed of each rolling mill are sequentially changed, and at least two types of A product and B product, or more plate thicknesses are obtained from the one material to be rolled. , or in a rolling control method for a continuous rolling mill that performs rolling to change plate thickness and plate width while producing a product with a plate width, a first rolling position setting value and a first rolling speed when rolling the above-mentioned A product. When changing the settings from the set values to the second rolling position set value and second rolling speed set value during rolling of product B, use a predetermined rolling model in advance.
While deriving the calculation results of the rolling position set value and rolling speed set value of the product, corrections are made based on the learning correction amount, manual setting correction amount, and rolling control operation performed during rolling of the A product. Find the multiplication result by multiplying the total amount by the correction gain, and add the above multiplication result to the rolling position setting value and rolling speed setting value of product B calculated using the above rolling model. A rolling control method for a continuous rolling mill, characterized in that settings are changed as a second rolling position set value and a second rolling speed set value during rolling of a product.