JP2541989B2 - Temper rolling method in continuous annealing equipment - Google Patents

Description

Detailed Description of the Invention

[Industrial applications]

The present invention relates to a temper rolling method in continuous annealing equipment, and in particular, it is suitable for use in continuous temper rolling of a cold rolled steel strip after continuous annealing in the same line, in a continuous annealing equipment. Improvement of quality rolling method.

[Prior art]

In recent years, cold-rolled steel sheets have been passed through a series of continuous production lines in which a continuous annealing furnace, a temper rolling mill, and a refining treatment device are continuously arranged, to obtain products. As a temper rolling mill for the above continuous production line, an intermediate roll shift type six-fold temper rolling mill has been widely used. However, when a sheet material is rolled by the 6-fold temper rolling mill, the rolling pressure suddenly rises at the intermediate roll shoulder of the 6-fold temper rolling mill, so that the roughness of the work roll portion abutting the shoulder is increased. Will decrease the degree. Therefore, when arranged and rolled so that the intermediate roll shoulder is located inside the plate width, the mark on the work roll due to the reduction of the roughness is transferred as a clear linear mark on the plate surface, Not desirable for product appearance. Further, when the position of the intermediate roll is near the same position as the plate width, the shape tends to change drastically. Therefore, the intermediate roll has a layout constraint that its shoulder must always be located outside the plate. Further, the movement of the intermediate roll is usually performed by a hydraulic cylinder, but the required movement time of the intermediate roll is extremely wide due to the set movement amount and the movement resistance caused by the rolling load, the roll surface condition, etc. In particular, there is a movement characteristic that it takes several seconds to several tens of seconds. From the above, in the continuous annealing equipment, in order to continuously process steel strips having different temper rolling conditions such as plate thickness, strip width, and steel type, the six-fold temper rolling is performed at different points of the temper rolling conditions. When controlling the intermediate roll position of the machine, the above-mentioned arrangement constraint of the intermediate roll position and its movement characteristics must be taken into consideration. By the way, various techniques have been conventionally proposed for controlling the intermediate roll position of a six-fold temper rolling mill. Among them, examples of continuous annealing equipment include, for example, Japanese Patent Publication No.
There is a temper rolling method for cold-rolled steel strip in a continuous annealing line, which is disclosed in Japanese Patent No. 087, in which a strip width changing welding point is detected and an intermediate roll position and a rolling pressure are changed to control a feed back.

[Problems to be Solved by the Invention]

However, the temper rolling method disclosed in the above publication does not consider the time required to move the intermediate roll position of the six-fold temper rolling mill. Therefore, there is a problem that when the intermediate roll position is moved at the point of changing the temper rolling conditions, rolling troubles such as a defective shape of the plate material or a narrowing of the plate material due to the defective shape often occur during the movement. To solve such a problem, a shape detector may be installed on the downstream side of the temper rolling mill, and the bending force of the work roll may be controlled and corrected by the output signal of the shape detector. Since there is a control delay due to the time required to reach the shape detector from the quality rolling mill or the time required to control the bending force, etc. Cannot be prevented.

[Object of the invention]

The present invention has been made to solve the above conventional problems, preventing the shape defect of the plate material in the moving process of the intermediate roll before and after the temper rolling condition change point of the plate material,
It is intended to provide a temper rolling method in a continuous annealing facility for making a plate shape flat and uniform over the entire length in the longitudinal direction of a plate material.

[Means for Solving the Problems] The present invention provides an intermediate roll shift type six-fold temper rolling mill as a temper rolling mill in the temper rolling section of a continuous annealing equipment, and the six-fold temper rolling mill is provided. When temper-rolling before and after the temper rolling condition change point of the plate material passed between the work rolls, the intermediate roll of the 6-fold temper rolling machine is moved before and after the temper rolling condition change point. , The position of the moving intermediate roll is detected momentarily, the shape influence coefficient is obtained momentarily from the detected position of the intermediate roll and the rolling load of the plate material, and the obtained shape influence coefficient and the plate material that change smoothly The object is achieved by controlling the roll bending force of the work roll by obtaining it momentarily and controlling the roll bending force according to the amount of shape modification required.

[Action]

In the present invention, when temper rolling the six-fold temper rolling mill before and after the temper rolling condition change point of the plate material, before and after going through the temper rolling condition change point, the intermediate roll of the six-fold temper rolling mill. Is moved, the position of the moving intermediate roll is detected momentarily, the shape influence coefficient is obtained momentarily from the detected position of the intermediate roll and the rolling load of the plate material, and the obtained shape influence coefficient is changed smoothly. Also, the roll bending force of the work roll is obtained momentarily and controlled according to the amount of shape modification required for the plate material. Therefore, during temper rolling of the plate material, it is possible to prevent the shape defect of the plate material in the moving process of the intermediate roll before and after the temper rolling condition change point, and to form the plate shape over the entire length of the plate material in the longitudinal direction. It can be made flat and uniform.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a rolling load P at a change point of a strip width W when rolling a steel strip by a six-fold temper rolling mill according to this example, and a reinforcing roll end portion when the upper and lower intermediate rolls are symmetrically moved. From the intermediate roll position X, the load width L of the work roll described later
And half the difference between the plate width W and Hcδ (= (L−W) / 2),
3 shows a temporal change of the bending force B and the bending force B.
2 shows the intermediate roll shift type 6 according to this embodiment.
It is a schematic block diagram of a heavy-duty temper rolling mill. The 6-high temper rolling mill shown in FIG. 2 has work rolls 12A and 12B for rolling the steel strip 10 by pressing it from above and below,
In order to suppress the bending of the work rolls 12A and 12B during rolling, the work rolls 12A and 12B are arranged in the vertical direction from an intermediate roll described later.
Reinforcing rolls 14A, 1 adapted to be supported via 16A, 16B
4B, the work rolls 12A, 12B and the reinforcing rolls 14A, 14B
Intermediate rolls 16A and 16B that are interposed between and are movable in the axial direction
A roll bending device 18 for positively giving a predetermined bending to the work rolls 12A, 12B, and intermediate roll position detectors 20A, 20B for detecting the axial movement position of the intermediate rolls 16A, 16B. With. In the case of the embodiment, the steel strip 10 is formed by welding steel strips having a strip width W and a strip width W ₂ around a temper rolling condition change point, for example, a welding point. Here, the symbol L in the drawing is the width in which the upper and lower intermediate rolls 16A and 16B overlap (the load width of the work roll), and the symbol Hcδ is 1/2 of the difference between the load width L and the strip width W of the steel strip, that is, The relative distance from the plate end of the steel strip 10 to the shoulder of the intermediate roll 16A.
When the sign of this relative distance Hcδ is positive, it indicates that the intermediate roll shoulder is located outside the plate edge. In addition,
Hcδ ₁ and Hcδ ₂ are plate widths W ₁ and W ₂ before and after passing through the welding point.
Is the relative distance corresponding to. The difference Hcδ is a value when the upper and lower intermediate rolls 16A and 16B move symmetrically. When the intermediate rolls move asymmetrically, the difference between the respective intermediate rolls and the load width (Hcδ = LW) is calculated for the upper and lower intermediate rolls. FIG. 3 shows an example in which the 6-fold temper rolling mill is provided on the line on the delivery side of the continuous annealing equipment. In the figure, the steel strip 10 is sent out from a continuous annealing equipment (not shown) in the direction of arrow A, and the sent steel strip 10 passes through the bridle roll 22 and then passes through the six-fold temper rolling mill. ing. A change point detector 24 for detecting a change point of the temper rolling condition of the steel strip 10 is provided on the entrance side of the bridle roll 22. The output signal of the change point detector 24 is input to the position calculator 26, and the position calculator 26 recognizes the position of the rolling condition change point from moment to moment based on the input signal. Also, the bridle roll 22 is
A pulse generator 28 for detecting the conveying speed and the distance of the steel strip 10 from the number of revolutions is connected, and the output signal of the pulse generator 28 is input to the position calculator 26. The output signal of the position calculator 26 is input to the preset calculator 30. The preset calculator 30 bends the work rolls 12A, 12B, the rolling force of the reinforcing rolls 14A, 14B, and the intermediate roll 16
The amount of movement control of A and 16B is predetermined (preset control). A shape detector 32 for detecting the plate shape after temper rolling is provided on the output side of the six-fold rolling mill, and an output signal of the shape detector 32 is input to a shape recognizer 34. The shape recognizer 34
Recognizes the shape of the steel strip 10 from the input signal, and its output signal is input to the controlled variable calculator 36. The control amount calculator 36, based on the input signal, the work roll 12
The deflection of A and 12B, the pressing force of the reinforcing rolls 14A and 14B, and the movement of the intermediate rolls 16A and 16B are feedback-controlled. The operation of the embodiment will be described below. When the temper strip rolling condition change point passes through the 6-fold temper rolling mill when the steel strip 10 is sent out from the continuous annealing equipment in the direction of arrow A, the change point detector 24 previously detects the change point together with the strip width. To detect. The output signal of the change point detector 24 is input to the position calculator 26 together with the output signal of the pulse generator 28, and the position calculator 26 recognizes the position of the change point moment by moment. On the other hand, in the preset arithmetic unit 30,
From the time T required to move the intermediate rolls 16A and 16B, the starting point a of the movement of the intermediate rolls 16A and 16B is taken into consideration in consideration of the strip speed v of the steel strip 10 and the traveling distance l from the change point detector 24 to the rolling mill. And set in advance. Here, in the time chart shown in FIG. 1, the regions indicated by reference signs a _{0 to} b ₀ are regions for controlling the intermediate roll position and the bending force according to the present invention. This area a ₀ ~ b ₀
Can be set at a predetermined distance or a predetermined time before and after the temper rolling condition change point. This area a ₀ ~
The intermediate roll position X corresponding to b ₀ is a and b, and the bending force B is a ′ and b ′. Therefore, the symbol a in the drawing is the movement start point of the intermediate rolls 16A and 16B, and b is the initial value of the position of the intermediate rolls 16A and 16B after the movement is completed. That is, the plate width W ₂
It is an initial value of the intermediate rolls 16A, 16B for the steel strip 10 of.
Reference numeral a'denotes a starting point for changing the bending force of the work rolls 12A and 12B, and reference numeral b'denotes an initial value after the completion of the changing of the bending force B. That is, it is the initial value of the bending force B for the steel strip 10 having the strip width W ₂ . In the areas other than the areas a _{0 to} b ₀ , the intermediate roll position x and the bending force B are fed back controlled by the control amount calculator 36. Regarding the rolling load P, the feed back control is performed before and after the strip width change point regardless of the regions a _{0 to} b ₀ . When the steel strip 10 is rolled and its temper rolling condition change point reaches the region a ₀ , at the same time, the intermediate roll 16
A and 16B start moving from the movement start point a of the intermediate roll position toward the initial value b after movement. In this case, the movement of the intermediate roll position X (t) can be performed, for example, according to the following equation (1). X (t) = a + [Hcδ ₂ −Hcδ ₁ ) + (W ₂ −W ₁ ) / 2] × (t / T) …… (1) However, T is required to move to points a to b Time, t
Is the current time on the move. Further, the moving intermediate roll position X (t) is detected by the position detectors 20A and 20B. The relative distance Hcδ is calculated from the detected intermediate roll position X (t), the strip width W ₁ of the steel strip 10 and the rolling load width L ₁ . From the relative distance Hcδ and the rolling load P, the shape influence coefficient α is calculated using the relationship shown in FIG. This shape influence coefficient α is a dimensionless number, and as shown in FIG. 4, is a ratio in which the shape of the plate material is influenced by the relative distance Hcδ and the rolling load P. Further, the shape influence coefficient α has a relationship with the required shape correction amount λ as the following expression (2). λ = αB ... (2) where α = f (P, Hcδ), α; shape effect coefficient (degree of rolling load on shape), λ: elongation rate (%) of steel strip in the strip width direction Maximum and minimum difference, B: Bending force, P: Rolling load, Hcδ; (load width-sheet width) / 2. On the other hand, for example, the required shape correction amount λ is calculated and determined in advance by the preset calculator 30 from the shape of the steel strip 10 detected by the shape detector 32. In this case, the required shape correction amount λ is the difference between the maximum value and the minimum value of the elongation rate (%) of the steel strip 10 in the strip width direction. Next, the change control of the bending force B of the work rolls 12A and 12B will be described. FIG. 5 shows an example of the relationship between the required shape correction amount λ and the bending force B (indicated by a value for each check), and takes various values with the shape influence coefficient α as a parameter. Regarding the change of the roll bending force B before and after the change point, for example, in FIG.
It is constant at 0ton, and the relative distance Hcδ is from + 20mm to -20mm
When it changes to (indicated by symbols f and e in the figure), the shape influence coefficient α is changed from 1.0 × 10 ⁻³ to 2.0 × 10 ⁻³ . Therefore, in FIG. 5, when it is desired to keep the required shape correction amount λ constant at an elongation rate of 0.05%, the bending force B is set to 35 ton / chock.
(The reference numeral in the figure) should be changed to 25 ton / chock (the reference numeral in the figure. Further, regarding the setting of the bending force B obtained as described above, the shape influence coefficient α is the intermediate roll position X.
(T) and the rolling load P change from moment to moment, so the optimum roll bending force B is also calculated momentarily at the same time, and the calculated roll bending force B is successively calculated within the regions a _{0 to} b ₀ . Set with. In this manner, at the end of which the bending force is sequentially set, the initial value b ′ of the roll bending force B for the steel strip 10 after the change point is set,
The control of the roll bending force B is completed. After the end, the roll bending force B is controlled by the normal feedback control. In addition, in the said Example, although the case where the method of this invention was implemented with the 6-fold temper rolling mill provided on the line which has a bridle roll as shown in FIG. 2 and FIG. 3, was illustrated, The temper rolling line for carrying out the method of the present invention is not limited to the arrangement configuration shown in the figure,
It is also possible to carry out the method of the present invention with lines having other configurations. Further, in the above embodiment, the shape influence coefficient is obtained from the intermediate roll position by using the relationship shown in FIG.
The correction amount of the bending force was obtained from the obtained shape influence coefficient and the required shape correction amount using the relationship as shown in FIG. 5, but when performing the method of the present invention, it is shown in these diagrams. The shape influence coefficient and the bending force are not limited to be obtained by the relationship described above, and the shape influence coefficient and the bending force can be obtained by other relationships according to the temper rolling conditions.

【The invention's effect】

As described above, according to the present invention, during temper rolling, the shape defect of the plate material in the intermediate roll moving process before and after the temper rolling condition change point is prevented, and the plate shape is formed over the entire length in the plate longitudinal direction. It is possible to obtain an excellent effect that the surface can be made flat and uniform.

[Brief description of drawings]

FIG. 1 shows an example of changes in the strip width, rolling load, intermediate roll position, relative distance, and bending force before and after the strip width change point when temper rolling a steel strip in an example according to the present invention. Diagram, FIG. 2 is a front view including a partial cross-sectional view showing a configuration example of a six-fold temper rolling mill used in the embodiment, and FIG. 3 is a continuous annealing facility in which the temper rolling mill is provided. An arrangement plan showing an example of a temper rolling line thereafter, FIG. 4 is a diagram showing an example of a relation for obtaining a shape influence coefficient from an intermediate roll position and a rolling load, and FIG. 5 is a figure showing the obtained shape influence. It is a diagram showing an example of a relationship for obtaining the bending force of the work roll from the coefficient and the required shape correction amount. 10 …… Steel strip (plate material), 12A, 12B …… Work roll, 14A, 14B …… Reinforcing roll, 16A, 16B …… Intermediate roll, 18 …… Roll bending device, 20A, 20B …… Intermediate roll position Detector, 24 …… Change point of temper rolling condition detector, 26 …… Position calculator, 30 …… Preset calculator, 32 …… Shape detector, 34 …… Shape recognizer.

Continuation of the front page (56) References JP 62-57704 (JP, A) JP 62-3818 (JP, A)

Claims (1)

(57) [Claims] 1. An intermediate roll shift type six-fold temper rolling mill is provided as a temper rolling mill in the temper rolling section of a continuous annealing equipment, and the rolling is performed between the work rolls of the six-fold temper rolling mill. When temper rolling before and after the temper rolling condition change point of the plate material, the intermediate roll of the 6-fold temper rolling mill is moved before and after the temper rolling condition change point, and the position of the moving intermediate roll The shape influence coefficient is obtained from the detected position of the intermediate roll and the rolling load of the plate material, and the shape change coefficient that changes smoothly and the shape correction amount required for the plate material are obtained. Accordingly, the temper rolling method in the continuous annealing equipment is characterized in that the roll bending force of the work roll is obtained momentarily and controlled.