JP3183207B2 - Continuous rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for continuously rolling a material to be rolled by a continuous rolling mill in which a plurality of stands are arranged in tandem.

[0002]

2. Description of the Related Art A rolled material heated to a required temperature in a heating furnace is supplied to a finishing mill in which a plurality of stands are arranged in tandem, where the rolled material is rolled to a product thickness. In order to roll the material to be rolled by the continuous rolling mill, the data such as the composition, dimensions, and product thickness of the material to be supplied is substituted into a preset mathematical model, and the material to be rolled at each stand is set. Calculate the target thickness, advance rate, reverse rate, etc., and adjust the roll-down position (roll gap) of each stand in advance using the calculation results. It is adjusted in advance so that the mass flow of the material to be rolled is constant. Then, the material to be rolled is inserted into each stand of the continuous rolling mill in which the rolling position and the roll peripheral speed are adjusted, and the material to be rolled is continuously rolled at each stand.

In such continuous rolling, the tension applied to the material to be rolled between the stands may be excessive or insufficient due to calculation errors of the advance rate and the reverse rate, and errors in the setting of the peripheral speed of the roll. There was a problem that the width or thickness of the material fluctuated. Further, if the tension is excessive or insufficient, the rolled material may break or an accident may occur in which a loop occurs in the rolled material.

For this reason, Japanese Patent Application Laid-Open No. 53-14146 proposes the following continuous rolling method. The rolling position of each stand and the peripheral speed of the roll are set in advance using the target thickness, advanced rate, reverse rate, etc. of the material to be rolled derived from the mathematical model, and the material to be rolled is inserted through each stand in order. Start rolling. Then, the speed at which the leading end of the material to be rolled passes between the i-th stand and the (i + 1) -th stand downstream thereof is detected to determine the actual advanced rate of the leading end, and the set advanced rate and the actual advanced rate are obtained. The difference from the ratio is calculated, and the roll peripheral speed of the i-th stand is corrected so that the calculated difference becomes zero.

However, this method has the following problems. No tension is applied to the leading end of the material to be rolled from the time when it passes through the i-th stand until before it is inserted into the (i + 1) -th stand. Is done. The method described above cannot cope with this tension variation, and when the material to be rolled is inserted into the (i + 1) th stand, the width or thickness of the material to be rolled fluctuates.

In order to solve this problem, Japanese Patent Laid-Open Publication No.
According to Japanese Patent No. 2410, based on the rolling performance of a plurality of materials to be rolled, the advance rate when no tension is applied to the material to be rolled between the i-th stand and the (i + 1) -th stand for each material to be rolled. And the advanced rate when the tension is applied are stored, and both advanced rates related to the material to be rolled similar to the material to be rolled are read out, and immediately before the material to be rolled is inserted into the (i + 1) th stand. A method of correcting the roll peripheral speed of the i-th stand by using the ratio of the two advanced rates read out has been proposed.

[0007]

SUMMARY OF THE INVENTION
In the method disclosed in Japanese Patent Application Laid-Open No. 1-192410, the roll peripheral speed of the i-th stand is corrected based on the rolling performance, so that it is impossible to cope with disturbance during the rolling of the material to be rolled. There is a problem that the roll peripheral speed of the i-stand cannot be corrected with high accuracy. In addition, since the rolling results of a plurality of materials to be rolled must be stored, a storage device having a large capacity is required, and there is a problem that the cost of the device is high.

The present invention has been made in view of such circumstances, and aims at two adjacent stands, in which the leading end of a material to be rolled is inserted into a rolling roll of a downstream stand. The upstream rate so that the advance rate of the material to be rolled in the upstream stand and the retreat rate of the material to be rolled in the downstream stand, and the peripheral speed adjustment amount obtained using the peripheral speed set in the downstream stand By adjusting the peripheral speed of the rolling roll of the stand, the fluctuation of the tension when the tip of the material to be rolled is inserted into the rolling roll of the downstream side stand is suppressed, and the fluctuation of the width or thickness of the material to be rolled is prevented. It is to provide a continuous rolling method.

[0009]

SUMMARY OF THE INVENTION A continuous rolling method according to the present invention is a method for rolling a material to be rolled by driving rolling rolls of a plurality of stands so that a preset peripheral speed is achieved in a continuous rolling mill. In the two adjacent stands, when the leading end of the material to be rolled is loaded into the rolling roll of the downstream stand, the speed of the material to be rolled between the two stands and the rolling roll of both stands The peripheral speed of each is detected, and the advanced rate of the material to be rolled at the upstream stand and the reverse rate of the material to be rolled at the downstream stand are calculated using these detected values, and the calculated advanced rate, reverse speed and downstream rate are calculated. The method is characterized in that the peripheral speed adjustment amount of the rolling roll of the upstream stand is obtained using the peripheral speed set in the side stand, and the peripheral speed of the rolling roll is adjusted with the obtained peripheral speed adjustment amount.

FIG. 2 is an explanatory view for explaining the principle of the method of the present invention, in which S is a material to be rolled. The material S to be rolled is conveyed in the direction of the arrow, and an i-th stand provided with a pair of upper and lower work rolls for rolling the material S to be rolled and a backup roll for supporting the work rolls in a conveyance area of the material S to be rolled. The i-th and (i + 1) -th stands ♯ (i + 1) are arranged in tandem at appropriate distances.

The work rolls of both stands #i, ♯ (i + 1) have a target thickness h _{n of the} material S to be rolled on the exit side of the final stand, an advance rate f _{n of} the material S to be rolled at the final stand,
The initial set peripheral speed V _Rn of the work roll of the final stand, the target thickness h _j (j = i, i) of the material to be rolled on the exit side of the stand
+1), advance rate f of the material S to be rolled at the stand
_j is substituted into the following equation (1) derived from the constant law of mass flow, and is set so as to be the initially set peripheral velocity _VRj . The initially set peripheral speed V _Rn of the work roll in the final stand is determined based on the target temperature of the material S to be rolled on the exit side of the final stand, the cooling capacity in a cooling step as a subsequent step, and the like. V _Rj = V _Rn · {(1 + f _n ) h _n / (1 + f _j ) h _j } (1)

Here, the speed v _{out, i} of the material S on the exit side of the i-th stand #i and the speed v _{in, i of the} material S on the entry side of the (i + 1) th stand # (i + 1). ₊₁
Is given by the following equations (2) and (3), respectively. v _{out, i} = (1 + f _i ) V _Ri (2) vin _{, i + 1} = (1-bi _{+ 1} ) V _{Ri + 1} (3) where b: reverse speed

Now, if the mass flow of the material S to be rolled is constant between the i-th stand #i and the (i + 1) -th stand # (i + 1), the following equations derived from the equations (2) and (3) are obtained. Equation (4) holds. V _Rrefi = V _{Ri + 1} · {(1−b _{i + 1} ) / (1 + f _i )} (4) where V _{Rrefi is} the peripheral speed adjustment amount of the work roll of the i-th stand.

In the present invention, from the i-th stand #i
The tip of the pressed material S is the (i + 1) th stand
When press-fitted into に (i + 1), the i-th stand
Pressure applied between (i + 1) th stand♯ (i + 1)
Speed of rolled material S, i-th stand #i and (i + 1) -th
The peripheral speed of the work roll of
At the i-th stand #i using the detected values.
Advanced rate f of material S to be rolled _Ai, The (i + 1) th stand {(i
+1) Reverse speed b of material S to be rolled_{Ai + 1}Is calculated.
At this time, v_{out, i}= V_{in, i + 1}= (Both stands ♯i, ♯
(Speed of the material S to be rolled during (i + 1))
f_AiAnd reverse speed b_{Ai + 1}Is calculated.

The calculated advanced rate f _Ai and reverse rate b
_By substituting _{Ai + 1} into the equation (4), the peripheral speed adjustment amount _VRrefi of the work roll of the i-th stand #i is obtained, and the work of the i-th stand #i is _set to the obtained peripheral speed adjustment amount _VRrefi. Adjust the peripheral speed of the roll. As a result, the mass flow is kept constant before and after the tip of the material S to be rolled is loaded into the (i + 1) th stand # (i + 1).
Is suppressed, and the width and thickness of the material S to be rolled are prevented from fluctuating.

[0016]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing a continuous rolling apparatus used for carrying out the method of the present invention and a control system thereof. In FIG. The material S to be rolled is conveyed in the direction of the arrow, and a pair of upper and lower work rolls 11 for rolling the material S to be rolled and a backup for supporting the work rolls 11 are provided in a conveying area of the material S to be rolled. Roll 12,
The first to seventh stands # 1 to # 7 each having 12 are arranged in tandem at appropriate distances. Also, the stands # 1 to # 7 are provided with pressing devices 15, 1 for adjusting the pressing position by the work rolls 11, 11 and applying a load to the material S to be rolled.
5, a motor M for rotating the work rolls 11, 11
Are provided, and the rolling-down operation of the rolling-down devices 15, 15,... And the rotation speed of the motors M, M,.
, And the peripheral speed control devices 18, 18,.

The work rolls 11 of the stands # 1 to # 7,
Are provided with peripheral speed meters 19, 19,... For detecting the peripheral speed, and the detection results of the peripheral speed meters 19, 19,. ,... And an advanced rate / reverse rate calculation unit 3 of the control device 2 described later. Further, speed detectors 20, 20,... For detecting the speed of the material S to be rolled by, for example, a laser Doppler system are provided between the adjacent stands, and the respective speed detectors 20, 20,. Is supplied to the advanced rate / reverse rate calculation unit 3.

The work rolls 11 of the stands # 1 to # 7,
The initial set value calculator 1 for calculating the initial set values of the rolling position and the peripheral speed of 11,... Is based on the target temperature of the material to be rolled S on the exit side of the final stand, the cooling capacity in a cooling process as a post process, and the like. The initially set peripheral speed V _R7 of the work rolls 11 of the seventh stand # ₇ is obtained. Also, the initial set value calculator 1
, The target thickness h _{i (i} = 1~7) of the rolled material S of each stand ♯1~♯7 delivery side, forward slip f _i of the rolled material S is given at each stand ♯1~♯7 is and the initial setting value calculator 1, the initial setting the peripheral speed V of the stand ♯1~♯6 by the following equation (5), which were derived from the mass flow constant law _R1-6
Is given to the peripheral speed control devices of the corresponding stands # 1 to # 7, and the obtained initial set peripheral speed V _Ri is obtained.
Work rolls 11, 11 ~♯7, ... motor M as peripheral speed is initially set peripheral velocity V _Ri of, M, ... a rotational speed to the initial settings. V _Ri = VR ₇ · {(1 + f ₇ ) h ₇ / (1 + f _i ) h _i } (5)

The initial set value calculator 1 calculates a target thickness h _i (i = 1 to 1) of the material S to be rolled on the exit side of each of the stands # 1 to # 7.
7) and each stand 種
The initial set-down positions in the respective stages # 1 to # 7 are obtained and given to the respective step-down controllers 16, 16,... Of the stands # 1 to # 7, and the work is set so that the stands # 1 to # 7 are set to the initial set-down positions. Initialize the positions of rolls 11, 11, ....

The advance rate / reverse rate calculation section 3 calculates the rolling rate of the material S to be rolled.
The tip passes through the ith stand #i (i = 1 to 6)
(I + 1) stand♯ (i + 1) work rolls 11, 11
Waits until it is caught in the
Between the stand #i and the (i + 1) th stand # (i + 1)
The speed v of the material S to be rolled from the speed detector 20 _i
And the i-th stand @ i and the (i + 1) -th stand
周 The peripheral speed V from the peripheral speed meters 19, 19 of (i + 1)_Ri, V_{Ri + 1}
Respectively, and based on the following equations (6) and (7),
And the advanced rate f of the material S to be rolled at the i-th stand #i
_AiAnd the pressure applied at the (i + 1) th stand ♯ (i + 1)
Reverse rate b of rolled material S_{Ai + 1}Is calculated, and the calculated advanced rate f_AiPassing
And reverse rate b_{Ai + 1}Is given to the peripheral speed adjustment amount calculation unit 4. f_Ai= (V_i-V_Ri) / V_Ri … (6) b_{Ai + 1}= (V_{Ri + 1}-V_i) / V_{Ri + 1} … (7)

The above-mentioned initially set peripheral speed V _Ri is also given to the peripheral speed adjustment amount calculation unit 4, and the peripheral speed adjustment amount calculation unit 4 receives the advanced ratio f _Ai and the reverse speed b
_{Ai + 1} and the (i + 1) th stand ♯ (i + 1) the initial set peripheral velocity V _{Ri + 1} are substituted into the following equation (8) to adjust the peripheral velocity of the work rolls 11 and 11 of the ith stand #i. V _Rrefi is calculated and _supplied to the peripheral speed control device 18 of the i-th stand #i to adjust the peripheral speed of the work rolls 11 and 11 of the i-th stand #i. As a result, the leading end of the material S to be rolled is positioned at the (i + 1) th work roll 11, (11).
This suppresses a change in tension that occurs when the rolled material S is bitten, and prevents a change in thickness and width of the material S to be rolled. V _Rrefi = V _{Ri + 1} · {(1-b _{Ai + 1} ) / (1 + f _Ai )} (8)

[0022]

Next, the results of a comparative test will be described. A low carbon steel sheet having a thickness of 2.0 mm and a width of 1250 mm is continuously rolled by the method of the present invention and the method described in JP-A-1-192410, and the tension applied to the material to be rolled and the material to be rolled Was measured for each width.

FIG. 3 is a graph showing the results of measuring the tension applied to the material to be rolled when rolling by the method of the present invention. FIG. 5 is the result of measuring the tension applied to the material to be rolled when rolling by the conventional method. FIG. Figure 3,
In FIG. 5, the vertical axis indicates the tension and the horizontal axis indicates the time, and at the point indicated by the arrow, the leading end of the material to be rolled is engaged in the downstream stand. FIG. 4 is a graph showing the result of measuring the width of the material to be rolled when rolling by the method of the present invention, and FIG. 6 is a graph showing the result of measuring the width of the material to be rolled when rolling by the conventional method. It is. 4 and 6, the vertical axis represents the width deviation, and the horizontal axis represents the longitudinal position of the material to be rolled.

As is apparent from FIG. 5, in the conventional method, immediately after the leading end of the material to be rolled is engaged with the downstream stand, an excessive tension is generated as compared with the target tension. As shown in FIG. 6, a large width variation occurs in the material to be rolled. On the other hand, in the method of the present invention, as is apparent from FIG. 3, even immediately after the leading end of the material to be rolled has caught in the downstream stand, no excessive tension is generated as compared with the target tension. Therefore, as shown in FIG. 4, the width variation does not occur much in the material to be rolled.

[0025]

As described above in detail, in the continuous rolling method according to the present invention, even when the leading end of the material to be rolled is immediately caught in the rolling stand, an excessive tension compared to the target tension is obtained. The present invention produces excellent effects, such as preventing the occurrence of fluctuations in the width or thickness of the material to be rolled without causing the occurrence of fluctuations.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a continuous rolling mill used to carry out the method of the present invention and a control system thereof.

FIG. 2 is an explanatory diagram illustrating the principle of the method of the present invention.

FIG. 3 is a graph showing the results of measuring the tension applied to a material to be rolled when rolling is performed by the method of the present invention.

FIG. 4 is a graph showing the results of measuring the width of a material to be rolled when rolling is performed by the method of the present invention.

FIG. 5 is a graph showing the results of measuring the tension applied to a material to be rolled when rolling is performed by a conventional method.

FIG. 6 is a graph showing a result of measuring a width of a material to be rolled when rolling is performed by a conventional method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Initial setting value calculator 2 Control device 3 Advanced rate / reverse rate calculation unit 4 Circumferential speed adjustment amount calculation unit 15 Roll-down device 16 Roll-down control device 18 Circumferential speed control device 19 Circumferential speed meter 20 Speed detector M Motor S Rolled material

Claims (1)

(57) [Claims] 1. A method for rolling a material to be rolled by driving rolling rolls of a plurality of stands so as to have a preset peripheral speed in a continuous rolling mill, wherein the two stands are adjacent to each other. When the leading end of the material to be rolled is loaded into the rolling rolls of the downstream stand, the speed of the material to be rolled between the two stands and the peripheral speed of the rolling rolls of the two stands are detected, and these detected values are calculated. Using the advanced rate of the material to be rolled in the upstream stand,
Calculate the retreat rate of the material to be rolled at the downstream stand and calculate the peripheral speed adjustment amount of the rolling roll of the upstream stand using the calculated advanced rate and reverse rate and the peripheral speed set at the downstream stand. A continuous rolling method comprising adjusting a peripheral speed of a rolling roll with a peripheral speed adjustment amount.