JPH0475709A - Controlling method of thickness for continuous hot rolling mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a plate thickness control method for a continuous hot rolling mill.
In particular, the present invention relates to a plate thickness control method that allows obtaining a good thickness from the tip of the strip.

[Prior Art 1] In order to obtain the desired thickness from the tip of the hot strip, it is necessary to set the gap between the rolls placed under rolling in each stand of a continuous hot rolling mill to an appropriate value. The rolling position of each stand is often set by a computer based on rolling theory formulas (rolling load formula, deformation resistance formula, gauge meter formula, etc.). However, there are problems with the accuracy of the rolling theoretical formula itself, and there are errors in the input values required for calculation (for example, the surface temperature of the material to be rolled at the finishing entry side), so it is difficult to set the optimal rolling reduction. is not always carried out, and it is difficult to obtain a good thickness from the tip of the hot strip. Therefore, in order to obtain a good thickness from the tip of the hot strip, it is necessary to correct the rolling position of each stand to an optimum value during sheet threading. Therefore, for example, Japanese Patent Laid-Open No. 59-144510 proposes a method in which a thickness gauge is installed between stands and the reduction amount or rolling load is corrected and controlled based on the detected thickness deviation of the material to be rolled. Furthermore, Japanese Patent Application Laid-Open No. 61-86019 proposes a gauge meter type plate thickness control method in which the plate thickness is determined using a gauge meter type and the rolling position is controlled so that the target plate thickness is achieved. [Problems to be Solved by the Invention] However, as in JP-A-59-144510, in the feedforward method of plate thickness control that corrects the rolling position based on the plate thickness deviation detected between stands, the rolling mill (
As the roll gap changes due to play in the coil (mill), rolling roll wear, thermal expansion, etc., errors occur in the roll gap setting, making it impossible to perform optimal rolling correction, making it difficult to obtain the desired thickness from the tip of the coil. Met. In addition, in the gauge meter type plate thickness control where the rolling position is corrected based on the plate thickness determined using the gauge meter type, as in JP-A No. 61-86019, the control mN degree dominates the accuracy of the gauge meter type. However, there was a problem in that the accuracy of the gauge meter type was limited. The present invention was made to solve the above-mentioned conventional problems, and compensates for the drawbacks of the conventional feed-forward method and gauge meter method of thickness control, and achieves good control from the tip of the hot strip. It is an object of the present invention to provide a method for controlling plate thickness in a continuous hot rolling mill that can obtain the desired plate thickness. Means for Solving Problems] The present invention provides a method for controlling plate thickness in a continuous hot rolling mill, in which at least one thickness gauge and at least one thermometer are installed between the stands, and the thickness of the material to be rolled is measured. When the tip passes through the i-th stand, the exit plate thickness, surface temperature, rolling position, and rolling load of the i-th stand are detected, and from these detected values, the first
The offset amount of the gauge meter type at the stand is calculated, and the offset amount of the gauge meter type at the i+1st stand is predicted from this value, and at the same time the rolling load at the i+1th stand is detected, the gauge corrected by this offset amount is calculated. Based on both the amount of reduction position correction based on the exit side plate thickness of the i+1st stand, which is determined using the meter formula, and the amount of reduction position correction due to feedforward control of the ++1st stand, which is obtained from the exit side plate thickness and surface temperature of the 1st stand. , the above-mentioned problem is achieved by determining the amount of correction of the reduction position of the i+1th stand.

[Action and effect]

In the present invention, the plate thickness at the exit side of the front stand, the rolled material table IN! In addition to the gauge meter type plate thickness control that accurately detects the rolling load and the rolling load, determines the gauge meter type offset amount for the next stand based on these detected values, and corrects the rolling position based on this offset amount. The feedforward method of plate thickness control, which corrects the rolling position of the next stand based on the plate thickness and surface temperature at the exit side of the previous stand, is used in combination, so the shortcomings of each are compensated for and continuous hot rolling is improved. It is possible to perform optimal reduction correction of the machine and obtain good plate thickness from the tip of the hot slip.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. The configuration of a continuous hot rolling mill consisting of f stands to which the present invention is applied is as shown in FIG. Each stand of this continuous rolling mill includes a work roll 10 for rolling a material to be rolled (hot strip) 8, a backup roll 12 for reinforcing the work roll 10, and a rolling load applied through the backup roll 12. It is mainly provided with a load meter 14 for detection and a roll position detection device 16 (also used as a roll position control IIA device) 16 for detecting the roll position of the work roll 10. Furthermore, a thickness gauge 20 and a thermometer 2 for implementing the present invention
2 is installed, for example, between the i-th stand and the i+1-th stand. In the figure, 30 is a meter for controlling according to the present invention. The control procedure of this embodiment will be explained in detail with reference to FIG. 1 below. First, in step 110, after the material to be rolled 8 is bitten by the i-th stand, the rolling load Pi (or rolling load deviation ΔPi) of the first stand is detected by the load meter 14. At the same time, the lowering position detection device 1G detects Si (or lowering position deviation ΔSi)'%g of the lowering position of the first stand5.
Furthermore, the exit side plate thickness 111 (or exit side plate thickness deviation Δ1]i) is detected from the thickness: t 20 on the exit side of the first stand. At the same time, the thermometer 22 measures the surface temperature Toi of the rolled material 8.
(or Toi to surface temperature deviation) is also detected. Next, the process proceeds to step 120, and using the following formula, the gauge meter type off-celler at the i-th stand]・number ΔSoi
Calculate. ΔS o i = h i−< S i + P i
/ M i ) ・= < 1) Here, M is Mill's constant. Next, the process proceeds to step 130, and using the offset/amount ΔSoi of the first stand, the change ΔS to the gauge meter type A'set 1 at the i+1th stand is calculated by the following equation.
Calculate Oil. ΔS Oil = k ill・ΔSoi
(2) Here, k is a constant determined from the rolling conditions and stand number 13 Next, the process proceeds to step 140, where the rolled material 8 is rolled to the next i+th
At the same time when the 1st stand is bitten, the rolling load Pi is measured by the load meter 14 of the 11th-1st stand. 1 (or rolling load deviation ΔPi or 1), the rolling position Sr, + (or rolling position deviation ΔSill) is detected by the rolling position detection device 1G, and the off-seller l-1ΔS o calculated by the formula 2> i
Using the following formula, which is the gauge meter formula for the i+1-th stand corrected in ll, the i->-1 stand outlet side plate thickness hi and 1 are calculated. h ill = S i−+ +(Pμ+ / M
(3) Next, proceed to step 150, and use the following formula to calculate the gauge meter-based reduction position modifier ΔS'i+l of the 1st + 1st stand. Δb'i",, I −G' +61 ・(
M+Q)/M ・(h B-+ h o i-
+) -(4) Here, G'←measuring constant, Q is the plasticity coefficient, and h is the target exit side plate thickness. On the other hand, in step 210, following step 110,
In parallel with steps 120-150, the reduction lower l correction amount ΔS″i+1 due to the feedforward 111111 of the i+1th stand is calculated using the following equation using the first stand exit side plate thickness bH and the exit side surface temperature Toi. A S ” in = −G ” kl ” (1/
M ill )((3P/aH) i, + ・(h i
-ho i )+ (al P/aT)t-+
・((aT/aTo)・T i,t −To
i, +3 ・−(5) Here, G”
l is a constant, (aP/H)- is the rolling load Pμ of the i+1st stand
m, the entry side plate thickness of the i+1st stand H=+(-ith
Influence coefficient of stand exit plate thickness 12), (b P /
a T ) +4. + Ha, lii +1 Start Q
)rolling? The influence coefficient of rolling temperature T1.1 of the rolled material of the i+1st stand on tjl Pill, (a T / ; 3 T o ) i−+ is
Rolling temperature T of the stand. 1 is the influence coefficient of the surface temperature Toi of the rolled material on the exit side of the first stand. After completing steps 150 and 210, step 310
Proceed to step 1, and as above, calculate the reduction position correction amount ΔSr by the gauge meter formula calculated in (), 1 and the reduction position correction tΔS"i by feedforward control. From the beginning, the reduction position of the 1st + 1st stand is determined by the following formula Correction amount ΔS ill
Calculate. ΔS ill−α・ΔS'i*I+β・ΔS II,
(6) Here, α and β are coefficients (0≦
α, β≦1). In this formula (6), α-1 and β-〇, or α-
〇And β~1, the amount of reduction position correction ΔSi, I−ΔS
As 'i*I or ΔS''μm, depending on the rolling conditions, only the reduction position correction amount is determined by gauge meter type, or
It is also possible to only adjust the amount of reduction position correction by the feedforward w41ml. Next, the process proceeds to step 320, where the roll-down position WPi correct amount ΔS kl obtained in step 310 is output to the roll-down position control device of the 1+1 stand, and the roll-down position of the work roll 10 of the 1-1-1 stand is corrected. do. In the 7-stand hot continuous rolling mill, a thickness gauge and a thermometer were installed on the exit side of the 6th stand, and the target final exit side plate thickness was 2.
, 31111 and 5. (For a 71 m hot strip (width 1200 mm), the present invention method, a comparative method in which only feedforward thickness side splitting was performed based on the thickness deviation detected by a thickness gauge, and a conventional method with uncontrolled elongation) The tip plate thickness accuracy (standard deviation of the final exit side plate thickness deviation) when carrying out each method is shown in Table 1 below.As is clear from Table 1, according to the method of the present invention, the tip of the pot strip From this, we were able to obtain a good plate thickness.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing one procedure of an embodiment of the plate thickness control method for a hot continuous rolling mill according to the present invention, and FIG. 2 shows the configuration of an example of hot rapid continuous rolling to which the present invention is applied. FIG. 8... Material to be rolled, 10... Work roll, 12... Backup roll, 14... Load cell, ΔP1... Rolling load deviation, 16... Rolling position control device, ΔS+... Rolling position deviation, 20...Thickness gauge, Δh1...Outside plate thickness deviation, 22...Thermometer, ΔTo+...Surface temperature deviation, Pi...Rolling vJ! ! F! , Sl...Reduction position, hl...Outside plate thickness, Tel...Surface temperature, 30...Calculator, ΔSol, ΔSokl...Offset amount, Δ3
1. and i...the correct amount of pressure lower ** by gauge meter type, ΔS″i and Bi...the correction amount of pressure lower W by feedforward I!IIO, and △S1 and bi...the correction amount of pressure lower II by feedforward I!IIO.

Claims (1)

[Claims] (1) In a hot continuous rolling mill, at least one thickness gauge and at least one
A thermometer is installed on the stand, and when the tip of the material to be rolled passes the i-th stand, the
Detect the exit plate thickness, surface temperature, rolling position, and rolling load of the stand, calculate the gauge meter type offset amount at the i-th stand from these detected values, and calculate the gauge meter type offset amount at the i+1th stand from this value. As soon as the rolling load at the i+1st stand is detected,
The amount of reduction position correction based on the exit side plate thickness of the i+1 stand obtained using the gauge meter formula corrected by this offset amount, and the reduction based on the feedforward control of the i+1 stand obtained from the exit side plate thickness and surface temperature of the i-th stand. 1. A method for controlling plate thickness in a continuous hot rolling mill, characterized in that a rolling position correction amount of the i+1th stand is determined based on both position correction amounts.