JPH012712A - Method for preventing squeezing of rolled steel sheets during continuous hot rolling - 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 "Field of Industrial Application" The present invention relates to a method for preventing squeezing of a rolled steel plate during continuous hot rolling.

1-Prior Art" In recent years, various high-precision plate crown control machines have been put into practical use, and there is a demand for producing flat steel plates without sloped crowns.

However, if the slope crown is small, 1llfj will meander during rolling and a squeezing accident will likely occur.

In general, the following +11 techniques are used to prevent meandering of steel plates.
A method for controlling the parallel stiffness of a rolling mill as shown in the following equation has been put into practical use.

αe−Pdf/to 1+5df=low---fi+(
In Equation 11, Kt' is the parallel stiffness coefficient (tons/m), αe is the control constant, Pdf is the load deviation between the left and right sides of the rolling mill (tons), and S
df is the leveling reduction amount (opening control?-).

In other words, the above equation +11 assumes that the center line of the steel plate deviates from the center of the rolling roll and that a load m deviation Pdf occurs on the left and right sides of the rolling mill, and the parallel rigidity coefficient of the rolling roll is set to 1. , due to the above deviation load, a roll opening deviation of Pdf/to/ occurs.

Therefore, the meandering control is performed so as to correct the roll opening deviation using Equation 11.

In addition, as for Haku's conventional meandering prevention technology, for example,
There is a method disclosed in Japanese Patent No. 8-51771, which detects triple rolling on the operation side and drive side of the rolling mill, calculates the ratio to the sum of the differences between the two loads, and calculates the ratio based on this ratio. This is intended to prevent meandering by adjusting the opening degree of the left and right rolls.

"Problems to be Solved by the Invention" The meandering control technology based on the formula (!) above has four problems on the left and right sides of the rolling mill:
Recognizing the fluctuation of Im deviation Pdf as meandering of the steel plate, Q
in (used so that the Ia difference Pdf remains constant (so-called relative value control).

That is, the load deviation P df when control is started.

is set as positive, and control is performed so that P df P dfo is achieved.However, since the meandering amount (off-center amount) of the steel plate is not directly detected, if the steel plate is off-center when the meandering control is locked on, the steel plate There is a problem in that it is controlled so that it is off-center.

In addition, the technology disclosed in the above-mentioned patent is a feedback control that adjusts the left and right roll opening degrees after meandering occurs, so high speed and high responsiveness of the rolling system are required. Therefore, hydraulic pressure reduction becomes essential.
A large amount of investment is required for equipment modification, and ;) a long period of equipment outage is required for equipment modification.

Furthermore, with feedback control, even if a high-response hydraulic pressure reduction means is used, the hydraulic pressure reduction leveling speed is 10 to 20 m.
At 17 seconds, the leveling reduction was insufficient for the high-speed passage of the tail end of the rolled steel plate, and therefore the left and right roll openings could not be adjusted sufficiently, resulting in frequent squeezing. There is a problem.

The present invention has been made to solve the above-mentioned conventional problems, and is a technology that makes it possible to control the rolled steel plate so that it always passes through the center of the rolling mill, and that can reliably prevent accidents caused by squeezing of the rolled steel plate. The purpose is to provide

"Means for Solving the Problems" The present invention provides, in continuous hot rolling of steel plates, the detection value of the meandering amount of the rolled steel plate on the exit side of the rolling mill, the meandering amount experimentally determined in advance, the roll shift position, the rolling Steel plate dimensions, rolling load,
Based on the relational empirical formula for leveling reduction amount, the correction error and leveling reduction position 11σ correct amount are calculated between the standard rolling time and rolling condition 9 with zero meandering amount, and the calculated value of the leveling reduction lower l correction amount is calculated. This is a method for preventing run-in of a rolled steel sheet during continuous hot rolling, which is characterized by performing meandering control using the following methods.

The present invention will be explained below.

Figures 1 to 3 show experimentally determined results regarding the left-right asymmetry characteristics of rolled steel sheets for 82 types of materials.

That is, FIG. 1 shows the load deviation Pdr? on the left and right sides of the rolling mill. !
: 1Eljiffl P (WDMI!l'l?Ti1
fi Pd + work 1 (Il'1 (Wffi Pw)
2 shows the relationship between the thigh deviation Pdf and the leveling reduction amount 5df (drive side reduction position Sd - working 1 side reduction lower i! Z S w ), and FIG. The relationship between Pdf and the off-center amount×l of the rolled steel plate is shown.

From the relationships shown in FIGS. 1 to 3, the following +21 It approximately holds true.

Pdf=f(xi, xw, h, W, ni, xl)X P
X5df + α --- (2) In formula 121, r is intermediate roll shift) fflxi, rolling roll shift Hxw, stand exit side Fiuh, stand exit 1ull Fi width W, parameters k and n representing the hardness of the rolled steel plate: It is a function of the off-center amount Xt+ of the rolled steel plate.

Note that xi and xw as variables of f are applied to a rolling mill having intermediate roll shifting means and rolling roll shifting means.

In addition, α is the asymmetry that is not taken into account in equation (2), such as the detection error between the load detectors on the drive side and the work side, the error in the leveling reduction position during caliper silencing, and the plate width of the rolled steel handling port body. This is due to uneven heat in the direction.

In other words, the i2+ formula shows that it cannot be said that the load m deviation Pdf=O is necessarily the off-center amount xl=o of tjA MHz.

From the above equation (2), the following equation (3) can be obtained at the timing.

ao= Pdfo −f(xio, xwo, ho,
Wo+ko+++f)X P o X S dfo −
--------(31st, off center mxe: xβ0
Considering the case where it is 0, the leveling reduction amount in this case is given by the following equation (4).

Therefore, from the above equations (3) and (4), the leveling reduction position correction amount ΔSat required to correct the off-center amount of the rolled steel plate is given by the following equation (5).

ΔS, 1 f = S d f ' - S d f
o------------ff1l The off-center of the rolled steel plate is corrected by the leveling reduction position correction 9ΔSdf of the above equation (5).

"Example" Figure 4 shows the stand of a continuous hot rolling mill, where (1) shows upper and lower rolling rolls, (2) shows upper and lower intermediate rolls, and (3) shows a stand of a hot continuous rolling mill.
are the upper and lower bathoquaf rolls, and the meandering amount (off-center amount) of the rolled steel sheet S is measured by the meandering amount detection device 4 installed on the exit side of each stand.

Figure 5 shows the rolled steel in the front stage stand shown in Figure 4! Fig. 2 is a block diagram showing an embodiment of the present invention of a method for preventing narrowing down of Fis, and the meandering amount detection of the rolled steel sheet S determined by the meandering detection device 4 is transmitted to the arithmetic device 5.

The arithmetic unit 5 stores a specific form of the equation (2).

The arithmetic unit 85 uses the transmitted meandering detection value to calculate the pressure SL using equations (3), (4), and (5).
Necessary to set the off-center amount of iWI I and S to 0,
; Calculate the leveling reduction position correction amount ΔSdf.

The calculated leveling reduction position correction amount ΔSdr is divided into two, corrections are made to the reduction setting values in mutually opposite directions, and each corrected reduction setting value is transmitted to the work side reduction control device (including the reduction position detection device) 6. and the drive-side roll-down control device (including the roll-down position detection device) 7, respectively.

The transmission timing of each revised reduction setting value is based on the off signal of the front stage stand by the load detector 8 on the work side and the load detector 9 on the drive example, and the IE jE schedule (
It is determined by the amount of reduction of each stand and the number of roll rotations).

Each of the roll-down control devices 6.7 performs roll-down position control based on the corrected roll-down setting values.

In addition, 10 is each shift device (including a shift position detection device) of the upper and lower rolling rolls 1, and 11 is each shift device (also including a shift position detection device) of the upper and lower intermediate rolls 2.

"Effects of the Invention" As described above, the present invention provides the detection value of the meandering amount of the rolled steel plate at the exit side of each stand of a continuous hot rolling mill, the meandering amount experimentally determined in advance, the roll shift position, and the rolled steel plate dimensions. , the correction error and leveling reduction position correction amount in the standard rolling time and in the rolling state with zero meandering amount are calculated based on the experimental formula of the relationship between rolling load and leveling reduction amount, and the calculated value of the leveling reduction position correction amount is calculated. Because the meandering control is performed by
Pressure! It is possible to reliably eliminate the off-center of the steel plate,
It is possible to prevent narrowing accidents from occurring.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between load deviation and rolling load, Figure 2 is a graph showing the relationship between load deviation and leveling reduction amount, and Figure 3 is a graph showing the relationship between ftm deviation and off-center amount of rolled steel plate. 4 is an explanatory diagram showing an example in which a meandering amount detection device is installed on the exit side of a stand of a hot continuous rolling mill to which the method of the present invention is applied, and FIG. 5 is a block diagram showing an example of the method of the present invention. It is a diagram. l... Rolling roll, 2... Intermediate roll, 3... Bar/quasoprol, 4... Meandering amount detection device, 5...
Arithmetic device, 6... Production 10...
- Shifting device for rolling rolls, It... Shifting device for intermediate rolls τ, S... Rolled steel plate 1tf 1 person Kawasaki Steel Co., Ltd. - 1', + Managing agent Yoshio Imaoka, Patent attorney 1st 1st figure
Figure 2: Point ≦ A5゜chamber P level ° link °
Pressure ≦tif Figure 3

Claims (1)

[Claims] In continuous hot rolling of steel plates, the experimental formula for the relationship between the detected value of the meandering amount of the rolled steel plate at the exit side of the rolling mill, the meandering amount experimentally determined in advance, the roll shift position, the rolled steel plate dimensions, the rolling load, and the amount of leveling reduction. Based on this, the correction error and leveling reduction position correction amount are calculated between the standard rolling time and the rolling state with zero meandering amount, and the meandering control is performed based on the calculated value of the leveling reduction position correction amount. A method for preventing squeezing of rolled steel sheets during continuous rolling.