JPH06297012A - Roll bending force setting device for hot mill - Google Patents

Abstract

PURPOSE:To accurately set a roll bending force by making the roll bending force calculated by a roll bending force calculation part a set value to the second and succeeding materials to be rolled after a pair of work rolls is changed. CONSTITUTION:When the second and succeeding materials to be rolled are rolled after a pair of work rolls 2 are changed, the respective actual values of a calculated value for a rolling load given to the material 1 to be rolled, the rolling load given when the neighborhood of a tail end part of the material just before the material to be rolled is rolled and a roll bending force is used to find a set value for the roll bending force at the time of the correction of a work roll crown changed with the advance of rolling. The roll bending force can accurately be set and stable rolling can be carried out by such a method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll bending force setting device for a hot rolling mill.

[0002]

2. Description of the Related Art The quality of a material rolled by a rolling mill is
It is evaluated by the plate thickness accuracy in the longitudinal direction (rolling direction) and the plate thickness accuracy in the plate width direction (direction perpendicular to the rolling direction).

As a standard for determining the plate thickness accuracy in the plate width direction, there is a plate crown. As shown in FIG. 2, when the plate thickness at the center of the plate width is hc and the plate thickness at the end of the plate width is he, the plate crown Ch is represented by Ch = hc-he (1).

The plate crown Ch in the equation (1) is a value after the material to be rolled is rolled. In the case of a material to be rolled by a four-high rolling mill as shown in FIG.
Is generally estimated by the equation (2).

Ch = αpP-αcwRcw-αcBRcB-αBFB + ηCho (2) Equation (3) is obtained by rearranging this equation (2) for FB.

FB = (αp · P−αcw · Rcw−αcB · RcB + η · Cho−Ch) / αB (3) where P is a rolling load applied to roll the material to be rolled, Rcw is a work roll crown, RcB is a backup roll crown, but the work roll crown Rcw
As for the backup roll crown RcB, as shown in FIG. 3, the diameter of the roll center is lc and the diameter of the roll end is le.
Then, it is represented by the difference between lc and le.

FB is a roll bending force applied to the work roll so that a predetermined work roll crown is given to the work roll in order to obtain a predetermined plate crown, and Cho is an entrance side plate before being bitten into the rolling mill. Crown, αp is the rolling load influence coefficient for the rolled out side plate crown, αcw is the work roll crown influence coefficient for the rolled out side plate crown, αcB is the backup roll crown influence coefficient for the rolled out side plate crown αB is the The work roll bending influence coefficient for the delivery side crown, η is called the crown genetic coefficient,
The coefficients representing the relationship between the entrance side plate crown change amount and the exit side plate crown change amount are shown.

The values of P, Rcw, RcB and Cho are determined by measurement or prediction calculation. Also, αp, αcw, αcB,
The values of α B and η can be calculated by theoretical calculation. Then, these values are substituted into the equation (3) to obtain the roll bending force so that the rolled material has a predetermined plate crown.

[0009]

In the conventional device, P,
The values of Rcw, RcB, Cho, αp, αcw, αcB, αB and η are estimated, and these values are substituted into the equation (3) to obtain the roll bending force applied to the work roll.

The work roll crown Rcw and the backup roll crown RcB are represented by the sum of the initial crown by polishing the work roll, the thermal crown by the thermal expansion of the work roll, and the work roll crown change amount by the wear of the work roll. Among them, the initial crown can be measured after polishing the work roll.

However, it is difficult to estimate the thermal crown and the work roll crown change amount by measurement or predictive calculation, because they change intricately as the rolling progresses. Therefore, the accuracy of the set value of the roll bending force becomes poor.

An object of the present invention is to solve the above problems and to provide a roll bending force setting device for a hot rolling mill which can set the roll bending force with high accuracy.

[0013]

In order to achieve the above object, the present invention provides a rolling load calculation unit for calculating a rolling load to be applied to a material to be rolled, and a rolling load calculation unit near the tail end portion of the material to be rolled. A rolling load detection unit that detects the rolling load applied to the rolled material, a roll bending device that detects the roll bending force applied to the work roll during rolling in the vicinity of the tail end of the material to be rolled, and the rolling load. Rolling load calculated by the calculation unit, the rolling load detected by the rolling load detector, and the roll bending force detected by the roll bending device is input, and the value of the roll bending force applied to the work roll is calculated, A roll bending force output unit for outputting to the roll bending device, and the roll is applied to the second and subsequent rolled materials after the work rolls are rearranged. Providing roll bending force setting device for a hot rolling mill, characterized in that the set value a calculated roll bending force bindings force computing section.

[0014]

According to the present invention, when the second and subsequent rolled materials are rolled after the work rolls are recombined, the calculated value of the rolling load applied to the rolled material when correcting the work roll crown which changes with the progress of rolling, The set value of the roll bending force is obtained by using the rolling load when rolling the vicinity of the tail end of the material to be rolled before this and the actual value of each roll bending force. By such a method, the roll bending force can be accurately set, and stable rolling can be performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an example in which the roll bending force setting device of the present invention is applied to a tandem rolling mill. The tandem rolling mill is composed of two stands equipped with a bending device.

Reference numeral 1 denotes a material to be rolled, which advances in the direction of the arrow Y and is rolled by the work roll 2 at that time. A backup roll 3 is arranged outside the work roll 2. A rolling load detector 4 detects a rolling load on the material 1 to be rolled.

Then, the work roll 2 is exchanged,
Further, when the rearrangement is performed by polishing or the like, the set value of the roll bending force calculated in advance and stored in the table 9 is calculated before the rolling of the first rolled material 1 is performed. It is indexed by the extraction unit 6. Then, the set value indexed by the roll bending force extraction unit 6 is supplied to the roll bending device 5. The roll bending device 5 sets the roll bending force applied to the work roll 2 based on the supplied set value.

When the roll bending force is set on the work roll 2, the first work material 1 is rolled after the work roll 2 is recombined. After this, the second and subsequent rolled materials 1 are sequentially rolled.

When the second and subsequent rolled materials 1 are rolled, the roll bending force applied to the work roll 2 is calculated by the roll bending force calculator 8.

Here, a method of calculating the roll bending force will be described.

When calculating the roll bending force, first, actual values of rolling load and roll bending force are detected. Note that the perspective view of FIG. 4 is a diagram for explaining the fact that the actual values of the rolling load and the roll bending force are detected. The same parts as those in FIG. 1 are designated by the same reference numerals, and the duplicate description will be omitted.

Assuming that the first rolled material 1a advances in the rolling direction indicated by arrow Y, the rolling load and the roll bending force are the timing at which the vicinity of the tail end portion (10 in FIG. 4) of the rolled material 1a is rolled. Detected in. In addition, it is desirable that the rolling load and the roll bending force be detected at a position as close as possible to the tail end of the material 1a to be rolled. However, the tail end portion is not always flat in shape, and the thickness thereof is slightly different, so that it is detected in the vicinity of the tail end portion.

[0024] The detected rolling load detected value ^{P A,} and the roll bending force detection value FB ^A, (3) are substituted into ^{equation, FB A = (αp · P} A -αcw · Rcw-αcB · RcB + η · Cho- Ch) / αB (4).

Further, the next rolled material 1 following the rolled material 1a
Substituting the rolling load calculation value P ^C for b and the roll bending force setting value ^{F B C} to be obtained into the formula (3), ^{F B C} = (αp · P ^C −αcw · Rcw −αcB · RcB
+ ΗCho-Ch) / αB (5) is obtained.

After the completion of rolling of the first rolled material 1a and the start of rolling of the next rolled material 1b, the times are close to each other, so that the thermal crown of the work roll and wear of the work roll due to thermal expansion. It is considered that the work roll crown changes due to are almost equal. Therefore, the values of the work roll crown Rcw and the backup roll crown RCB in the expressions (4) and (5) are almost equal.

In general, the rolled material 1a is the (k) -th rolled material and the rolled material 1b is the (k + 1) -th rolled material in the equations (4) and (5). ), (k + 1) When the subscript taking the difference of both ^{sides, FB C (k + 1)} -FB a (k) = (αp / αB) · Δ
P. This summary for ^{FB C (k + 1) (} 6) is obtained.

F ^{B C} (k + 1) = ^{F B A} (k) + (α p / α B) ΔP (6) where ΔP = P ^C (k + 1) −P ^A (k) (7) The roll bending force is calculated from the equation).

By the way, after the work rolls 2 have been recombined, when the second and subsequent rolled materials 1 flow from the upstream portion, the roll bending force calculation unit 8 (FIG. 1) uses the rolling load calculation unit 7 The calculated value P ^{C of the} rolling load applied to the rolled material 1 calculated in step 1 and the actual result of the rolling load detected by the rolling load detector 4 during rolling in the vicinity of the tail end of the preceding rolled material 1. From the value P ^A , the rolling load difference ΔP is calculated by the equation (7).

[0030] Then, the a rolling load difference [Delta] P, and a result value FB ^A of roll bending force detected by the roll bending apparatus 5, roll bending force FB adding the during rolling of the rolled material 1 against the work rolls 2 ^C is calculated by the equation (6), and the calculation result is output to the roll bending device 5.

[0031] roll bending device 5, roll bending force FB ^C calculated by the roll bending force calculating section 8 is input to control the roll bending force applied on the basis of this value to the work roll 2, the second or subsequent The material 1 to be rolled is continuously rolled. Incidentally, the roll bending device 5 has a function of detecting a roll bending force FB ^C when rolling the material 1 to be rolled, and roll bending force FB exerted by the roll bending force calculating section 8
^C has a function of controlling the roll bending force applied to the work roll 2.

The above control is repeated every time the work roll 2 is recombined. That is, after the work rolls 2 are rearranged, the rolling of the first rolled material 1 is the value calculated in advance and stored in the table 9, and the rolling of the second and subsequent rolled materials 1 is performed by the roll bending force calculation unit. With the value calculated in 8, the roll bending force is set and rolling is performed.

Although the embodiment of FIG. 1 shows two four-high rolling mills, the present invention can be similarly applied regardless of the number of rolling mills. Further, the control as described above is performed for each rolling mill.

[0034]

According to the present invention, the value of the work roll crown, which changes according to the progress of rolling, is corrected by the actual value when rolling the vicinity of the tail end portion of the preceding rolled material, so that The precision of roll bending force during rolling is improved, and stable rolling can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining a plate crown.

FIG. 3 is a diagram for explaining a roll crown.

FIG. 4 is a perspective view illustrating how to detect actual values of rolling load and roll bending force.

[Explanation of symbols]

1 ... Rolled material 1a ... Rolled material 1b ... Rolled material 2 ... Work roll 3 ... Backup roll 4 ... Rolling load detector 5 ... Roll bending device 6 ... Roll bending force extraction unit 7 ... Rolling load calculation unit 8 ... Roll Bending force calculation unit 9 ... Table 10 ... Rolling load and roll bending force detection point 11 ... Roll P ^A ... Rolling load detection value P ^C ... Rolling load calculation value FB ^A ... Roll bending force detection value FB ^C ... Roll bending force setting value hc ... rolled material plate width center plate thickness he ... rolled material plate thickness in the vicinity of plate edge lc ... roll center diameter le ... roll end portion diameter FB ^A (k) ... (k) rolled material tail end vicinity of the roll bending force actual value ^{P a (k) ... (k} ) rolling load actual value of the rolled material tail end vicinity of the first ^{FB C (k + 1) ...} (k + 1) pair the rolled material of the present th Roll bending force setting value P ^C (k + 1) ... (k + 1) Rolling load calculation value for the (k + 1) th rolled material

Claims (1)

[Claims] 1. A rolling load calculation unit for calculating a rolling load applied to a rolled material, and a rolling load detection unit for detecting a rolling load applied to the rolled material during rolling near the tail end of the rolled material. The roll bending device detects the roll bending force applied to the work roll during rolling near the tail end of the material to be rolled, the rolling load calculated by the rolling load calculation unit, and the rolling load detector detects the rolling load. The rolling load, and the roll bending force detected by the roll bending device are input, the value of the roll bending force applied to the work roll is calculated, and the roll bending force calculator is provided to output to the roll bending device. Roll bending force calculated by the roll bending force calculation unit for the second and subsequent rolled materials after the work rolls are rearranged A roll bending force setting device for a hot rolling mill, characterized in that: