JPH0587326B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to rolling condition setting control for a multi-high continuous rolling mill, and in particular to a rolling condition setting correction method for a continuous rolling mill that corrects the set values of the rolling position and rolling speed based on the rolling results of the previous stage stand. It is related to. [Prior Art] Normally, when operating a rolling mill, various set values are predicted in advance based on the rolling conditions of the material to be rolled, and the set values are set in the rolling mill before rolling. However, these setting values are not always optimal. Therefore, as a control method that corrects this set value according to the rolling results obtained during rolling, the
Issue 2061 has arrived. The conventional Japanese Patent Publication No. 51-2061 calculates the rolling position correction amount as follows by using the following well-known rolling load formula (1) and gauge meter formula (2). That is, P _i =k _i (T _i , h _i-1 , h _i , N _i )・B・√′ _i
( _i-1 − _i )・Q _i (h _i-1 , h _i )…(1) h _i =S _i +P _i /M _i +S _pi …(2) However, the subscript i in the above formula indicates the stand number. where P is rolling load, k is deformation resistance, T is rolling material temperature (hereinafter referred to as temperature), h is plate thickness, N is rolling speed,
B is the plate width, R' is the flat roll radius, Q is the rolling force function, S is the rolling position, M is the mill constant, and S _p is the offset amount. In the second stand in the above known example,
Assuming that the influence of the entry/exit plate thickness deviation on the rolling load deviation is practically small, using the partial equation regarding only k in equation (1), the deviation ΔP ₂ between the measured rolling load and the predicted rolling load of the second stand is calculated as follows: , the deformation resistance deviation Δk ₂ of the second stand is calculated as Δk ₂ =k ₂ /P ₂ ΔP ₂ ...(3), and the deformation resistance deviation of the third and subsequent stands is Δk _i =Δk ₂ =k ₂ /P ₂ ΔP ₂ ...(4), the rolling load deviation is predicted as ΔP _i =P _i /k _i k ₂ /P ₂ ΔP ₂ ...(5), and the rolling position correction amount is calculated as follows regarding P in equation (2). It is calculated as ΔS _i =ΔP _i /M _i =−P _i k ₂ /M _i k _i P ₂ ΔP ₂ (6) using a partial differential equation. That is, in FIG. 1 showing the embodiment of the present invention, only P ^m ₂ is detected by the rolling load detection device 4 of the second stand, and ΔP ₂
The rolling position S _i is calculated from =P ^m ₂ -P ₂ .
Since the rolling condition setting correction method of conventional continuous rolling mills was done as described above, the influence of the thickness deviation at the entrance and exit sides of the second stand on the rolling load deviation of the second stand is 100 to 200 ton/mm even for ordinary steel. can be,
Approximate influence of deformation resistance deviation on rolling load deviation
Although it is equivalent to or higher than 100 tons (Kg/mm ² ), this conventional method ignores the influence of the thickness deviation on the rolling load deviation at the entrance and exit sides of the second stand, so the equation (3) above An error of double or half occurs in Δk ₂ obtained by , and as a result, there is a drawback that an accurate reduction position correction amount cannot be calculated by equation (6). [Summary of the Invention] This invention was made to eliminate the drawbacks of the conventional products as described above. The side plate thickness deviation and rolling load deviation were calculated, and the rolling load deviation from the third stand onwards was accurately predicted, and highly accurate reduction position correction amounts and rolling speed correction amounts were determined and adaptive control was performed. The purpose of this invention is to provide a method for modifying rolling condition settings for a continuous rolling mill. [Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. First, in order to facilitate understanding, the process of deriving the reduction position correction amount will be explained. Note that each physical quantity below is the same as that explained in equations (1) and (2) above, Δ(·) represents the deviation between the actual measured value or true value and the predicted value, and n represents the final stand. Calculation of Plate Thickness Deviation In the above equation (2), S _pi and M _i are constant for the considered rolled material, so the partial equation of equation (2) is expressed by the following equation. Δh _i =ΔS _i +ΔP _i /M _i (7) Therefore, the deviation between the measured value and the predicted value of the rolling load and rolling position in the first and second stands ΔP ₁ ,
From ΔP ₂ , ΔS ₁ , and ΔS _{2 ,} the thickness deviations Δh ₁ and Δh ₂ on the entrance and exit sides of the second stand can be calculated using the following formula. Δh ₁ = ΔS _i + ΔP _i /M _i , where i=1, 2...(8) Note that Δh ₁ is the thickness deviation on the exit side of the first stand, and Δh ₂
is also the plate thickness deviation on the entrance side of the third stand. Calculation of Temperature Deviation In Equation (1), the flat roll radius R′ _i is expressed as a function of the plate thickness and rolling load, so the partial equation regarding each physical quantity in Equation (1) is expressed as Equation (9). ΔP _i = −Q _Ti ΔT _i +Q _Hi Δh _i-1 −Q _hi Δh _i +Q _Ni ΔN _i …(9) However, Q _T , Q _H , Q _h , Q _N are the temperature deviation,
These are the influence coefficients that the entry side plate thickness deviation, exit side plate thickness deviation, and rolling speed deviation have on the rolling load deviation. Note that the above-mentioned influence coefficient is expressed as a positive value. Therefore, the rolling load at the second stand,
Using the deviations ΔP ₂ and ΔN ₂ between the measured rolling speed and the predicted rolling speed, and Δh ₁ and Δh ₂ calculated by equation (8),
From equation (9), the second stand temperature deviation ΔT ₂ can be calculated using the following equation. ΔT ₂ = −ΔP ₂ +Q _H2 Δh ₁ −Q _h2 Δh ₂ +Q _N2 ΔN ₂ /Q Prediction of _T2 rolling load deviation Second stand temperature deviation ΔT ₂ obtained from the above equation (10)
is thought to spread to downstream stations in proportion to the temperature of each stand, so the temperature deviation ΔT _i of each stand can be predicted using equation (11). ΔT _i =T _i /ΔT ₂ ΔT ₂ , where i=3 to n...(11) Also, the purpose is to determine the amount of reduction position correction so that the exit side plate thickness deviation after the third stand is zero. Therefore, equation (12) holds regarding the plate thickness deviation. Δh _i = 0, however, i = 3 to n … (12) However, the entrance side plate thickness deviation of the third stand Δh ₂
exists, and is given by the thickness deviation of the exit side of the second stand in equation (8) above. Therefore, the rolling load deviation ΔP _i after the third stand can be predicted by equation (13) by substituting equations (11) and (12) into equation (9). ΔP ₃ =Q _T3 T ₃ /T ₂ ΔT ₂ +Q _N3 ΔN ₃ +Q _H3 Δh ₂ … (13-1) ΔP _i = −Q _Ti T _i /T ₂ ΔT ₂ +Q _Ni ΔN _i where i=4~n… (13-2) However, ΔN _i (i=3 to n) is the deviation between the actual rolling speed measured at any timing before the material to be rolled is bitten by the third stand and the predicted rolling speed. Determining the amount of correction of the rolling position Next, set the rolling position from the third stand onwards by Δh _i (i=3
-n). In this case, equation (14) is obtained from equation (7). ΔS _i =−ΔP _i /M _i , where i=3~n...(14) Therefore, when the material to be rolled is bitten into the second stand, the entry and exit side plates of the second stand are determined by equation (8). The thickness deviations Δh ₁ and Δh ₂ are calculated, the temperature deviation ΔT ₂ of the second stand is calculated using equation (10), and the temperature deviation ΔT 2 of the second stand is calculated using equation (11).
Calculate the temperature deviation ΔT _i (i = 3 to n) after the stand, calculate the rolling load deviation ΔP _i (i = 3 to n) after the third stand using equation (13), and then (14)
The reduction position correction amount ΔS _i (i=3 to n) can be determined from the formula. It goes without saying that the plate thickness deviation Δh ₁ on the entrance side of the second stand can be calculated when the material to be rolled is bitten into the first stand. In addition, by substituting equation (13) into equation (14), taking equation (10) into consideration, the following equation is obtained. _i
(i=3 to n) may be determined by the following equation. ΔS _i =−A _i・ΔP ₂ +B _i・Δh ₁ −(C _i +C′ _i )・Δh ₂ +
D _i・ΔN ₂ −E _i・ΔN _i , where i=3~n...(15)

〔Effect of the invention〕

As described above, according to the present invention, using the rolling results of at least two stands, the first and second stands, the entrance/exit plate thickness deviation and rolling load deviation of the second stand are calculated, Since the rolling position and rolling speed are automatically corrected based on these deviations, highly accurate corrections can be made, the target product thickness can be obtained from the tip of the rolled material, and the mass flow balance between each stand can be maintained. This has the effect of stabilizing operations.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a control system of a multi-stage continuous rolling mill showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Setting control device, 2... Initial setting control function part, 3... Setting correction control function part, 4... Rolling load detection device, 5... Rolling position detection device, 6... Rolling speed detection device, 7 ...Down position control device, 8...
Rolling speed control device.

Claims (1)

[Claims] 1. Before the material to be rolled is bitten by the continuous rolling mill, the rolling position and rolling speed of each rolling stand are predicted and set as predicted values, and when the material to be rolled is bitten by the first rolling stand, the rolling speed is predicted. The rolling load and rolling position of the first rolling stand are actually measured, and the entrance plate thickness deviation of the second rolling stand is calculated from the deviation between the measured value and the corresponding predicted value, and then the material to be rolled is transferred to the second rolling stand. The rolling load and rolling position of the second rolling stand and the rolling speed from the second rolling stand onward are actually measured, and the thickness deviation on the exit side of the second rolling stand is calculated based on the measured values and the corresponding predicted values. , the rolling load deviation, and the rolling speed deviation after the second rolling stand, and the calculated second
The rolling positions after the third rolling stand, and the first and second
A method for modifying rolling condition settings for a continuous rolling mill, comprising modifying the rolling speed of a rolling stand.