JP2795551B2 - Camber control method in hot rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a camber in a hot rolling mill, and more particularly, to moving a rolled material in a width direction by an edger roll (referred to as a rigid roll for correcting the width of the rolled material). And a control method for correcting a camber.

[0002]

2. Description of the Related Art Conventionally, a rough rolling facility in a hot rolling line generally includes a rough rolling mill provided with a rolling load cell and a roll gap adjusting device, and a pair of edger rolls provided on an entrance side of the rough rolling mill. The slab having a thickness of 250 mm is rolled into a strip of 20 to 40 mm by the rough rolling mill. The roll gap adjusting device provided in the rough rolling mill has a function of adjusting the gap between the upper and lower rolls and adjusting the level of the upper and lower rolls (also referred to as leveling) so that the rolled material has a predetermined thickness. Further, the pair of edger rolls is provided for adjusting the roll interval to control the width of the rolled material. The slab to be rolled by the rough rolling mill is heated to a predetermined temperature by a heating furnace, and the slab is uniformly heated in the width direction, and the temperature deviation in the width direction depends on heating conditions, slab loading state, and the like. Some have occurred.

[0003] The slab as described above is rolled to a predetermined thickness and width by a rolling mill and an edger roll. Depending on the shape and temperature of the slab or the rolling conditions, the steel strip (hereinafter referred to as rolled material) has a camber. (Bent) and wedges may occur. Conventionally, the camber thus generated is corrected by adjusting (leveling) the level of the roll.

[0004]

However, it is difficult to correct all shapes of the cambers and wedges generated as described above only by leveling, and the following problems exist. For example, (1) When a slab having a temperature difference in the width direction is rolled, and as shown in FIG. 2, when a slab having a temperature difference in the width direction is rolled, WS (work side) and DS (drive side) are used. Although the camber and meandering can be corrected to some extent by adjusting the roll level of the slab, this temperature difference is not always uniform in the longitudinal direction. And the high temperature part is WS
Side or the DS side, and it is impossible to make corrections by merely leveling adjustment. (2) When rolling a rolled material having a camber, when rolling a rolled material having a camber in a preceding rolling mill in a subsequent rolling mill, the angle of entry of the rolled material that is caught in the rolls changes. This further promotes camber, and conventional leveling adjustment alone cannot cope. (3) When rolling a rolled material with a thickness deviation (wedge), it is theoretically possible to correct the exit camber without changing the wedge ratio by leveling adjustment. If the deviation direction is changed, an electric rolling device having a slow response cannot be used, and a rolling mill provided with a hydraulic rolling device having excellent responsiveness is required. (4) When the center of the rolling mill and the width center of the rolled material are displaced (referred to as off-center), the off-center causes a difference in the rolling reduction between the left and right sides, which may cause camber. . In such a case, the function of the conventional edger roll (conventionally, an edger roll is provided only for adjusting the width and only the function of adjusting the roll interval is provided, but there is no function of moving the entire rolled material in the width direction. )
It was impossible to correct the off-center by moving the rolled material in the width direction. Further, the camber cannot be corrected only by adjusting the leveling. (5) When a difference in the friction coefficient of the work roll occurs between the WS side and the DS side, if the friction coefficient of the roll has a difference in the longitudinal direction, the rolled material shifts laterally and a camber is generated. In such a case, a roll change was performed to cope with the situation.
Camber occurs under the above conditions,
A general theoretical formula showing this phenomenon will be described based on the case of the temperature deviation in FIG. That is, the outgoing camber ρ ₀ is

(Equation 1) Equation (1) can be used.

The present invention has been made in order to solve the above-mentioned problems. In particular, the present invention is based on the phenomenological theory shown in the above equation (1), except for the conventional method of correcting camber by leveling adjustment. It is an object of the present invention to provide a camber control method in a hot rolling mill that corrects a camber by moving a rolled material in a width direction while calculating a camber ratio and the like.

[0006]

A camber control method in a hot rolling mill according to the present invention comprises a first stand provided with at least a rolling load measuring means and a roll gap adjusting means, and a first stand provided on an entrance side of the first stand. A first rolling equipment provided with a temperature measuring means for the rolled material, a thickness measuring means, and a position detecting means for detecting a position of the rolled material in the width direction on the entrance and exit sides of the first stand; Means and an edger roll for moving the rolled material in the sheet width direction are provided on the entry side of the n-th stand provided with the roll gap adjusting means, and the width direction position of the rolled material is set on the entry and exit side of the n-th stand. In a rolling line provided with an n-th rolling facility provided with a position detecting means for detecting, the thickness and temperature of the rolled material measured in the first rolling facility, the position in the width direction of the rolled material, the rolling load, the roll gap, etc. The wedge ratio, the camber ratio, and the temperature difference in the width direction of the rolled material are calculated, and the positional relationship between the center in the width direction of the rolled material and the center of the rolling mill is corrected so as to correct the camber of the rolled material based on these values. A feedforward control adjusted by a roll;
And a feedback control for calculating a camber based on the width direction position of the rolled material on the entrance and exit sides of the stand, and adjusting the position of the edger roll so as to correct the camber from this value.

More specifically, the wedge ratio, camber ratio, and width direction of the rolled material measured from the thickness and temperature of the rolled material measured by the first rolling equipment, the position in the width direction of the rolled material, the rolling load, and the roll gap are used. The temperature difference is calculated, the roll level of the first stand is adjusted so as to correct the camber of the rolled material based on these values, and the positional relationship between the center in the width direction of the rolled material and the center of the n-th stand is determined by the n-th rolling equipment. The camber is calculated based on the feedforward control adjusted by the edger roll and the width direction position of the rolled material on the entrance and exit sides of the n-th stand, and the position of the edger roll is adjusted from this value to correct the camber. This is a method of adjusting the roll level of the n-th stand together with the feedback control.

[0008]

In the method for controlling camber in a hot rolling mill according to the present invention, the wedge of a rolled material is determined from the thickness and temperature of the rolled material measured in the first rolling equipment, the position in the width direction of the rolled material, the rolling load, and the roll gap. Rate and the camber rate and the temperature difference in the width direction are calculated, and the positional relationship between the center in the width direction of the rolled material and the center of the rolling mill is corrected through feedforward control so as to correct the camber of the rolled material from these values. In addition to the adjustment by the edger roll, the camber is calculated based on the widthwise position of the rolled material on the entrance / exit side of the n-th stand, and the position of the edger roll is adjusted by feedback control so as to correct the camber from this value. Thereby, the camber can be controlled. The camber can be corrected more effectively by using the above-described means for controlling the edger roll and the conventional adjustment method using leveling.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for controlling camber in a hot rolling mill according to the present invention will be described below in detail with reference to the drawings. FIGS. 1 to 14 show a camber control method in a hot rolling mill according to the present invention. FIG. 1 is a block diagram showing a hot rolling mill, and FIGS. 2, 5, 8, 11, and 13 show rolling states. Plan configuration diagram, FIGS. 3, 4, 6, 7, 9, 1
Reference numerals 0, 12, 14, and 15 are cross-sectional views showing rolled materials (plates).

In FIG. 1, reference numeral 1 denotes a first stand which forms a first rolling equipment 50. The first stand 1 has a pair of first horizontal mills 3 for rolling a rolled material 2 and a pair of first horizontal mills 3. It comprises an intermediate roll 4, a load cell 5 as a rolling load measuring means, a first screw 6 as a roll gap adjusting means, and a first reduction 7, and a first leveling detection of the first reduction 7 from a first leveling detector 8. The signal 8a is input to the first stand wedge rate / camber rate controller 10.

The first load signal 5a from the first load cell 5, the first lateral displacement meter 11 and the lateral displacement meter 12 provided on both sides of the first stand 1 (in the width direction of the rolled material 2). The first entry side lateral displacement signal 11a and the first exit side lateral displacement signal 12a from the position detection means for detecting the position are input to the first stand wedge rate / camber rate control device 10.

A wedge signal 13a from a wedge meter 13 as a thickness measuring means and a thermometer 14 as a temperature measuring means provided on the upstream side of the first entry side lateral displacement meter 11 are provided.
And the temperature measurement signal 14a are the first stand wedge rate
The first stand leveling correction signal 10a from the camber rate control device 10 is input to the first reduction 7 as well.

The entry-side wedge ratio 1 from the controller 10
0b, entrance side camber rate 10c, entrance side width direction temperature difference 10
d is input to the n-th stand camber rate control device 15, and the leveling signal 15
The a and the n-th camber control signal 15b are input to the leveling device 16 and the hydraulic jack control unit 17, respectively.

Reference numeral 20 denotes an n-th stand which forms an n-th rolling equipment 51. The n-th stand 20 is a pair of second horizontal mills 2 for rolling the rolled material 2.
1, a pair of intermediate rolls 22, an nth load cell 23, an nth
A screw 24 and an n-th reduction 25, and a vertical mill hydraulic jack 2 is provided upstream of the n-th stand 20.
A pair of vertical mills 27 (only one is shown in the figure) as an edger roll operated by the hydraulic machine 6 is provided.
Jack control signal 17a.

A level control signal 16a from the leveling device 16 is input to the n-th reduction 25, and an n-th leveling detection signal 28a from an n-th leveling detector 28 connected to the n-th reduction 25 is input to the n-th reduction 25. The position is input to the n-stand camber rate control device 15 and is provided at both sides of the n-th stand horizontal mill 20 at the entrance side lateral deviation meter 29 and the exit side lateral deviation meter 30 (a position detecting device for detecting a position in the width direction). ) Are arranged.

The incoming lateral displacement signal 29a and the outgoing lateral displacement signal 30a of each of the lateral displacement meters 29, 30 are inputted to an n-th stand camber computing unit 31, which computes a signal 31a of the n-th stand camber computing unit 31. Is input to the n-th stand camber rate control device 15 and
The second load signal 23a from the load cell 23 is also input to the n-th stand camber rate control device 15.

Next, a case where camber control is performed using the hot rolling mill having the above-described configuration will be described.

(Example 1) First, when rolling a rolled material 2 made of a slab having a temperature difference in the width direction, as shown in FIG. 2, the high temperature side (DS) extends from the low temperature side (WS) and the low temperature side (WS) extends. A bending camber occurs on the side (WS). However, by moving the rolled material 2 in the width direction by the vertical mill 27 which is an edger roll, the camber can be corrected by the following operation. The low-temperature side (WS) and high-temperature side (DS) advanced rates fw, fd, reverse rates GW, gd, cambers on the ingress / egress side, angular velocity, and bar velocity are respectively ρi,
ρ ₀ , ω i, ω ₀ , Vi, V _0, and the low temperature side (WS) on the input side
Assuming that the rear long force on the high-temperature side (DS) is Tw, Td and the plate width is W, as is well known, the relationship of equation (1) is established between the camber on the entrance side and the angular velocity.

[0019]

(Equation 1)

The following equation (2) is obtained.

(Equation 2)

Now, considering the following rolling state, entry-side wedge zero → hidf = 0, ω ₀ = 0 entry-side camber zero → ρi = 0 Tw = Td Width-wise temperature difference WS <DS From the above equation (1) The following equation (4) is obtained.

[0022]

(Equation 3)

In the same rolled state, from the above equation (2),
The following equation (5) is obtained.

[0024]

(Equation 4)

Here, when the equation (5) is substituted into the equation (4), the following equation (6) is obtained.

[0026]

(Equation 5)

Therefore, according to the above equation (6), the camber ρ ₀ proportional to the outlet wedge h ₀ df generated by the difference in deformation resistance due to the temperature difference in the width direction occurs. Where h ₀ w> h ₀ d
Therefore, the rolling reduction γ becomes γw <γd, the advanced ratio fw <fd, and the reversing ratio gw <gd, the camber bends toward the WS side, the entrance side also leans toward the WS side, and a meandering of Δx occurs toward the WS side.

As a method of setting the camber to zero, a method of changing the mill center and the plate center of the rolled material 2 by the entry edger will be described. First, the edger is turned off-center by Δx with respect to the mill center toward the DS side. At this time, the above-mentioned Tw becomes a tensile force and Td becomes a compressive tension, and there is Δx that satisfies the following equation (7), whereby the exit camber can be made zero.

[0029]

(Equation 6)

Further, the off center of the entry side by the edger is maintained, and in the steady state, the off center of the roll bite becomes Δx. At this _{time, h 0 df = ASdf + BΔx} + CPdf ··· (8) However, Sdf is WS, screw position difference between the DS, then, it becomes a _{h 0 df = BΔx + CPdf =} 0 than Sdf = 0 of equation (8). That, Δx = (C / B) by creating a state of Pdf, (7) equation _{∂g / ∂h 0 · h 0 df} = 0, ∂g / ∂hi · hidf =
0, ∂f / ∂T · Tdf = 0, and rolling in the state of ρ ₀ = 0 is possible. That is, by the off-center control by the edger, camber and meandering due to the temperature difference in the width direction of WS and DS can be prevented in both the transition period (FIG. 5) and the steady region (FIG. 8).

(Embodiment 2) A case where a rolled material having a camber is rolled. If the rolled material is already cambered, the approach angle of the rolled material bitten by the roll changes, and the camber is further promoted on the exit side. However, when the rolled material is moved in the width direction by the edger roll, the camber can be corrected by the following operation.

Ρ ₀ determined by ρ i / λ ² in equation (1) of equation 1 is generated. In this case, it was difficult to control the approach angle with the conventional actuator.However, the values in the bar longitudinal direction of the camber detected upstream were stored, and the off-center amount of the edger corresponding to the approach angle change due to the change in ρi was fed. Control forward. The feedback control of the edger off-center amount is performed by the stand lateral displacement meter so that the roll bite position becomes constant. The influence of the incoming camber on the outgoing camber can be eliminated by each of the methods described above.

(Embodiment 3) In the case of rolling a rolled material having a thickness deviation (wedge). As shown in FIG. 11, when the entry wedge is thick on the DS side, a bent camber occurs on the rolled material WS side. Reduction rate γw <γd Advance rate fw <fd Reverse rate gw <gd, and the plate bends to the WS side, meanders to the WS side,
The exit side wedge is DS thick. However, when the edger roll is moved in the DS width direction as shown in FIG. 13, the camber can be corrected by the following operation. Off-center Δx
The control can be performed in the state of fw = fd and gw = gd by shifting, and the above-mentioned control can be performed by controlling the amount of Δx in accordance with the change of the wedge in the bar. In this case, the material wedge on the delivery side cannot be corrected, but the wedge can be allowed and controlled with priority given to camber prevention which is the most hindrance to rolling.

(Embodiment 4) A case where the center of the rolling mill and the width center of the rolled material are shifted (referred to as off-center). If the rolled material is bitten by the rolls with the off center, a difference occurs between the left and right reduction ratios (levels), and camber occurs. However, when the edger roll is moved in the width direction, the camber can be corrected by the following operation. h ₀ df = AS df + BΔx + CP df (9) The Δx component h ₀ df of the equation (9) is generated, and the camber and meandering of the change in the advanced rate and the reverse rate are generated. In this case, although it was difficult to control with the conventional actuator, by controlling the off-center amount of the edger adjust so that the off-center Δx = 0 from the leading edge by the lateral displacement meter 29 on the entrance side, the output camber can be controlled. , Meandering can be prevented. However, the above-mentioned Pdf is represented by Expression (10) of Expression 7.

[0035]

(Equation 7)

(Embodiment 5) A case where a friction coefficient occurs between WS and DS of a work roll. When a difference in the friction coefficient occurs, camber occurs and the roll is changed. However, when the edger roll is moved in the width direction, the camber can be corrected by the action as shown in the following equation (11).

[0037]

(Equation 8) A change h ₀ df in μdf occurs, and a camber occurs on the output side. The camber on the exit side is actually measured by the lateral displacement meters 29 and 30 provided on the entrance and exit sides, and the width direction control of the edger adjustment is performed so that ρ ₀ becomes zero. Although several examples have been described above, these different phenomena occur in combination in actual operation. Therefore, as the most effective control method, the temperature, camber, wedge, etc. are detected and calculated (estimated), and the edger roll is newly moved by feed-forward control and feedback control together with the conventional leveling adjustment. Can be modified.

[0038]

The camber control method in the hot rolling line according to the present invention is configured as described above, so that the following effects can be obtained. That is, the camber rate, the wedge rate, and the like are calculated, and the off-center amount is adjusted by moving the edger roll in the width direction.
The camber of the rolled material can be effectively corrected.
As a result, it becomes possible to pass the rolled material stably, eliminate the misroll due to the camber, and improve the yield and the operation rate.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a hot rolling mill according to the present invention.

FIG. 2 is a plan view showing a non-control state.

FIG. 3 is a cross-sectional view of a plate of a portion A in FIG. 2;

FIG. 4 is a cross-sectional view of a plate of a portion B in FIG. 2;

FIG. 5 is a plan view showing a control start state.

FIG. 6 is a cross-sectional view of a plate of a portion A in FIG.

FIG. 7 is a cross-sectional view of a plate of a portion B in FIG. 5;

FIG. 8 is a plan view showing a steady state.

FIG. 9 is a sectional view of a portion A in FIG. 8;

FIG. 10 is a sectional view of a portion B in FIG. 8;

FIG. 11 is a plan view showing a control state.

FIG. 12 is a sectional view of a portion B in FIG. 11;

FIG. 13 is a plan view showing a control state.

FIG. 14 is a sectional view of a portion A in FIG. 13;

FIG. 15 is a sectional view of a portion B in FIG.

[Description of Signs] 1 First stand 5 Load cell (rolling load measuring means) 6 First screw (roll gap adjusting means) 11 Lateral displacement meter (position detecting means) 12 Lateral displacement meter (position detecting means) 13 Wedge meter (plate) Thickness measuring means) 14 Thermometer (Temperature measuring means) 20 nth stand 27 Vertical mill (edger roll) 50 1st rolling equipment 51 nth rolling equipment

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-212418 (JP, A) JP-B-59-51362 (JP, B2) JP-B-62-55441 (JP, B2) JP-B-63 54444 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B21B 37/68 B21B 37/72

Claims (2)

(57) [Claims] A first stand (1) provided with at least a rolling load measuring means (5) and a roll gap adjusting means (6);
A temperature measuring means (14) and a sheet thickness measuring means (13) for the rolled material provided on the entrance side of the first stand (1);
A first rolling equipment (50) provided with position detecting means (11, 12) for detecting a position of the rolled material in the width direction on the entrance and exit sides of the rolled material; and a first rolling equipment (50) provided with at least rolling load measuring means and roll gap adjusting means. An edger roll (27) for moving the rolled material in the sheet width direction is provided on the entry side of the n-stand (20), and
In a rolling line provided with an n-th rolling equipment (51) provided with position detecting means (29, 30) for detecting a position of the rolled material in the width direction on the entrance side of the stand (20), a first rolling equipment The wedge rate, camber rate, and temperature difference in the width direction of the rolled material are calculated from the thickness and temperature of the rolled material measured in the above, the position in the width direction of the rolled material, the rolling load, the roll gap, and the temperature difference in the width direction. Feedforward control for adjusting the positional relationship between the center of the rolled material in the width direction and the center of the rolling mill so as to correct the camber by the edger roll, and camber by the widthwise position of the rolled material on the entrance / exit side of the n-th stand. And a feedback control for adjusting the position of the edger roll so as to correct the camber based on the calculated value. 2. The wedge ratio, camber ratio and width direction of a rolled material from the thickness and temperature of the rolled material measured by the first rolling equipment (50), the position in the width direction of the rolled material, the rolling load, and the roll gap. The temperature difference is calculated, the roll level of the first stand (1) is adjusted so as to correct the camber of the rolled material according to these values, and the position of the center in the width direction of the rolled material and the center of the n-th stand (20) is adjusted. The camber is calculated based on the feedforward control in which the relationship is adjusted by the edger roll of the n-th rolling facility, and the position in the width direction of the rolled material on the entrance and exit sides of the n-th stand (20), and the camber is corrected from this value. 2. The can in the hot rolling mill according to claim 1, wherein the roll level of the n-th stand (20) is adjusted together with the feedback control for adjusting the position of the edger roll. Over control method.