JP2738272B2 - Control method of tension between rolling stands - 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 tension between rolling stands of a tandem rolling system for molding a material to be rolled, and more particularly, to a method of transferring a material to be rolled between universal rolling mills respectively provided on a plurality of stands. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension control method between rolling stands for controlling a tension of a material to be rolled between rolling stands in a non-tension state in a rolling system that finishes a shaped steel or a bar having a predetermined shape by applying pressure while the rolling is being performed.

[0002]

2. Description of the Related Art A conventional method for controlling the tension between rolling stands is as follows.
This will be described with reference to FIG. In FIG. 2, 1 is a rolled material, 2 ₁ and 2 ₂ are rolling rolls of a universal rolling mill (front and rear rolling mills) provided on the front and rear stands,
3 ₁ and 3 ₂ are roll drive motors for driving the rolling rolls, 4 ₁ and 4 ₂ are motor drive circuits for driving the motor, 5 is a speed correction value calculation circuit, and 6 is a speed setting / correction circuit. is there. The tension control in the rolling operation of the conventional example is as follows: "tip lock-on" → "tip FTC (free tension control)" → "center lock-on" →
The control operation is executed in the cycle of “central portion FTC”, and the control operation in each cycle is as follows. In the following description, it is assumed that the material to be rolled 1 moves from the former rolling mill toward the latter rolling mill (in the direction of the arrow).

[0003] between the tip of the distal portion lock-on (cycle A) the material 1 to be rolled is bitten into the rolling rolls 2 ₁ of the preceding rolling mill until just before bitten rolling rolls 2 ₂ in the subsequent stage rolling mill , roll drive motor 3 ₁ of the rolling torque G _U1Ai in front rolling mill is a predetermined number of times (n times) measurement, the average value G _U1A0

G _U1A0 = ΣG _U1Ai / n (i = 1, 2,..., N) (1) is calculated and locked on, that is, stored. In addition,
The rolling torque is detected by detecting a current value supplied from a motor drive circuit to the roll drive motor.

[0004] tip FTC (cycle B) the tip portion of the rolled material 1, when bitten rolling rolls 2 ₂ of the subsequent rolling mill, roll drive motor 3 ₁ of the rolling torque G _U1B of the preceding rolling mill is measured , The difference between the rolling torque and the average value G _U1A0 stored in “Tip Lock On” is calculated, and the tension torque G _T

Equation 3] _{G T = G U1A0 -G U1B (} 2) is calculated. Using this difference G _T, roll driving motor 3 _second rotational speed correction value subsequent rolling mill △ N _2B is calculated as follows.

_{ΔN 2B} = (1 + T ₂ S) (G _Tref −G _T ) / T ₁ S (3) where G _Tref ; target tension torque T ₁ ; integral gain T ₂ ; advance compensation gain S; children the rotation speed correction value △ N _2B, roll driving motor 3 _second rotational speed N _2B the subsequent rolling mill been fixed, the tension torque G _T is controlled to be zero. As a result, free tension control (no tension control) is performed during the period in which the leading end of the material 1 to be rolled is processed by the subsequent rolling mill.

[0005] Just before processed by subsequent mill for central lock on (cycle C) tip of the rolled material 1 is finished, that is, just before the tip exits the rolling rolls 2 ₂ of the subsequent rolling mill, roll drive motor 3 _1, 3 ₂ of the rolling torque G _U1C, G _U2C is measured, the rolling torque ratio G _C

Equation 5] _{G C = G U2C / G U1C} (4) is calculated, its value is stored. From the tip of the central portion FTC (cycle D) the material to be rolled 1 comes out of the rolling rolls 2 ₂ of the subsequent rolling mill, to the rear end comes out of the rolling rolls of the preceding rolling mill, the roll drive motor 3 _1, 3 ₂ rolling torque G _U1D, G _U2D is measured at a predetermined sampling period, using the stored rolled torque ratio G _C these measurements and the "central locking on" roll driving motor 3 ₂ of the subsequent rolling mill speed correction value △ N _2D of, is calculated as follows.

[6] _{△ N 2D = (1 + T} 2 S) (G U2D / G U1D -G C) / (T 3 S) (5) Thus, the ratio G _U2D / G of the successive measured rolled torque in this cycle _U1D is, to match the stored rolled torque ratio G _C in a "central locking on", the rotational speed of the roll driving motor 3 ₂ of the subsequent rolling mill is modified appropriately.

[0006]

In the above conventional example, since the torque ratio is controlled to be constant (ie, G _C ) at the “central portion FTC”, the length of the material to be rolled is reduced. It was not enough to cope with the temperature drop in the direction. That is, since the temperature of the material to be rolled decreases in the latter half and the deformation resistance increases, the web thickness and the flange thickness are rolled thicker than in the first half. As a result, the tension between the stands acts in the pulling direction in the rear half of the material to be rolled, and it becomes impossible to perform rolling without tension. Therefore, an error exceeding the allowable value, that is, an out-of-tolerance may occur in the flange width or the like of the molded product. An object of the present invention is to solve the problems of the conventional example and to compensate for a change in tension caused by a change in temperature of a material to be rolled, so that a molded product with less out-of-tolerance can be obtained. An object of the present invention is to provide a method for controlling tension between stands.

[0007]

In order to achieve the above object, the present invention provides a method for rolling a material to be rolled on the basis of the principle of mass flow. Focusing on the point that it can be grasped as a change in the area, the rotation speed ratio N _2D / N _1D of the roll drive motors of the front and rear universal rolling mills detected in the “central portion FTC” is changed to The correction based on the change in the cross-sectional area is called “Central Lock-On”.
The first control is to control the rotation speed of the roll drive motor of the post-stage universal rolling mill so as to match the rotation speed ratio N _2D / N _1C of these roll drive motors detected in (1).
Is the point of focus. In the present invention, it is extremely difficult to detect the cross-sectional area of the material to be rolled during rolling. Therefore, instead of detecting the cross-sectional area, the central part lock-on and the central part FTC are replaced with a pre-stage universal. The horizontal roll sum load P _H1C , P _H1D , and the vertical roll average load P _V1C , P _V1D of the rolling rolls of the rolling mill are respectively detected to obtain a value corresponding to the change in the cross-sectional area of the material to be rolled. Is the second point of focus.

In view of the above, the method for controlling the tension between rolling stands according to the present invention comprises the steps of (a) moving a material to be rolled from a first universal rolling mill to a second universal rolling mill, In a state where the leading end is bitten by the second rolling mill, the rotational speeds N _1C and N _2C of the first and second roll drive motors of the first and second universal rolling mills are detected and stored, and A storage step of detecting and storing the horizontal roll sum load P _H1C and the vertical roll average load P _V1C of the first rolling roll, and (b) the material to be rolled is from the first universal rolling mill to the second universal rolling mill. And the rotation speeds of the first and second roll drive motors, N _1D , N _2D , and the first rolling mill until the trailing end of the material to be rolled exits the first universal rolling mill. Horizontal roll sum load of rolling roll The _H1D and vertical rolls Average Load P _V1D detected at a predetermined sampling period, a correction value △ N _2C of the rotational speed of the second roll driving motor, following expression

Equation 7] _{△ N 2D ≒ N 2D -N 2C} / N 1C × N 1D [1 + 2 -1 K {(P H1C -P H1D) / (a + bW U1) / t w1 '+ (P V1C -P V1D) / c / t _f1 '｝] (6) where K is a constant a, b, and c are constants related to the rigidity of the rolling mill W _U1 is a roll width t _w1 ' of the first rolling roll is a first The average web thickness t _f1 ′ when passing through the first rolling roll is obtained from the average flange thickness when passing through the first rolling roll, and the rotation speed of the second drive motor is N _2D − △ N _2D
It is characterized in that it comprises a correction step for correcting so that

[0009]

FIG. 1 shows an embodiment of the present invention.
1, the same components as those of the conventional example shown in FIG. 2 are denoted by the same reference numerals. Also, 7 ₁ and 7 ₂ are speed sensors for detecting the rotation speed of the roll drive motors 3 ₁ and 3 ₂ , and 8 ₁ and 8 ₂ are for detecting the horizontal roll sum load (P _H ) and the vertical roll average load (P _V ). Horizontal / vertical load cell. The rolling rolls of the section steel rolling mill are formed of a pair of horizontal rolls driven by a motor and a pair of vertical rolls driven by the rotation of the horizontal rolls. The horizontal / vertical load cells 8 ₁ , 8 ₂ are: The sum of the load of the pair of horizontal rolls (sum of the horizontal roll P _H ) and the mean load of the pair of vertical rolls (the average load of the vertical roll P _V ) are detected and supplied to the speed correction value calculation circuit 5.

Here, the principle of the present invention will be described. Note that in the present invention, the “tip lock-on (cycle A)” and “tip FTC (cycle B)” operate in the same manner as in the conventional example, and the “center lock-on (cycle C)” and “ The central part FTC (cycle D) "is characterized. In the “central portion FTC”, that is, when the leading end of the material to be rolled 1 is the rolling roll 2 _{1 of the} preceding rolling mill.
Up to exit, the roll driving motor 3 ₂ speed N _2D
Is corrected to the target rotation speed N _2D ′ by the rotation speed correction value △ N _2D , these relations are

ΔN _2D = N _2D −N _2D ′ (7) Then, the rotational speed ratio of the "central locking on" _{N 2C / N 1C (N 1C} ; roll driving motor 3 ₁ of rotational speed, N _2C; rotational speed of the roll driving motor 3 ₂₎ to match the "central Speed ratio N _2D '' in the section FTC
/ N _1D is controlled by

N _2D ′ / N _1D = N _2C / N _1C (8) In the present invention, equation (8) is corrected to perform temperature compensation.

For this reason, the present invention utilizes the fact that the temperature change of the material to be rolled can be detected as a change in the cross-sectional area of the material to be rolled according to the law of constant mass flow, and is caused by the temperature change of the material to be rolled. To compensate for tension fluctuations,
The target rotation speed N _2D of the roll driving motor 3 ₂ 'is to be corrected according to the change rate of the cross-sectional area of the material to be rolled.
That is, in the "central locking on" and the "central portion FTC", preceding the rolling rolls 2 ₁ of the rolled material 1 in cross-sectional area S _1C, the rate of change of S _1D the _{(S 1C -S 1D) / S} 1D determined, it may be corrected rotational speed of the roll driving motor 3 ₂ so as to satisfy the following equation (9).

N _2C / N _1C = N _2D ′ / N _1D × 1 / {1 + K (S _1C −S _1D ) / S _1D } (9) where K: correction coefficient (0.00 <K <2. 00) From equation (9)

N _2D ′ = ｛1 + K (S _1C −S _1D ) / S _1D ｝ N _1D N _2C / N _1C (10)

[0012] However, since the sectional area of the rolled material during rolling can not be measured directly, in the present invention instead, measurable reduction rolls 2 ₁ horizontal roll total load P _H1C
(At “horizontal section lock-on”), P _H1D (at “horizontal section FTC”) and vertical roll average load P
_V1C (at “horizontal section lock-on”) and P _V1D (at “horizontal section FTC”) are detected, and the cross-sectional area change rate (S _1C −S _1D ) in the above equation (10) is calculated based on these detected values. /
S _1D is obtained by the following calculation.

(S _1C −S _1D ) / S _1D {In (S _1C / S _1D )} 1/2 {In ( _{tw 1C} / _{tw 1D} ) + ln (t _f1C / t _f1D )} {1/2} _{(t w1C -t w1D) / t} w1C + (t f1C -t f1D) / t f1C} ≒ 1/2 (P H1C -P H1D) / (a + b × W U1) / t w1 '+1/2 (P V1C −P _V1D ) / c / t _f1 ′ (11) where, t _W1C ; the web thickness of the material to be rolled at “central portion lock-on” t _W1D ; the web thickness of the material to be rolled at “central portion FTC” t _f1C ; flange thickness t _f1D of the rolled material at the center lock-on ";" flange thickness of the rolled material at the center FTC "W _U1; the rolled material at the time of pass through a rolling mill; front rolling mill roll width t _w1 'of Average web thickness t _f1 ′; average flange thickness of the material to be rolled when passing through the pre-rolling mill a, b, c; constant determined by the size of the mill

The above constants a, b and c are, for example, a = 198 b = 0.057 c = 176 when a large section rolling mill is used. When a rolling mill is used, for example, a = 153 b = 0.222 c = 154, which is set according to the rolling mill. By substituting equation (11) into equation (10),

N _2D ′ = ｛1 + K (S _1C −S _1D ) / S _1D ｝ N _1D N _2C / N _1C ≒ N _1D N _2C / N _1C × [1 + 2 ⁻¹ K (P _H1C −P _H1D ) / (A + bW _U1 ) / tw ₁ ′ +2 ⁻¹ K (P _V1C −P _V1D ) / c / t _f1 ′] (12) is obtained. Thus, the rotational speed of the roll driving motor 3 ₂ of the subsequent rolling mill, by controlling so that the target rotational speed N _2D 'obtained by the above formula (12), to roll the material to be rolled with no tension Can be done. From equations (7) and (12), the rotational speed correction value △ N _2D is

Equation 14] _{△ N 2D ≒ N 2D -N 1D} N 2C / N 1C × [1 + 2 -1 K {(P H1C -P H1D) / (a + bW U1) / t w1 '+ (P V1C -P V1D) / c / t _f1 '｝] (13)

Returning to the above embodiment, the operation will be described. In “central part lock-on (cycle C)”, the speed sensors 7 ₁ and 7 ₂ detect the rotation speeds N _1C and N _2C of the respective roll drive motors 3 ₁ and 3 ₂ and supply them to the speed correction value calculation circuit 5. I do. The circuit calculates these ratio values N _C = N _2C / N _1C and stores the values in the memory in the speed correction value calculation circuit 5. Moreover, the horizontal / vertical load cells 8 _1, the rolling rolls 2 ₁ horizontal roll total load P _H1C, to detect the vertical roll Average Load P _V1C, and supplies the speed correction value calculating circuit 5,
It is stored in the memory in the circuit 5. And "Central FTC
(Cycle D) ”, but the speed correction value calculation circuit 5
_Stores the above W _U1 , t _w1 ′, t _f1 ′, and a, b, and c in advance. The speed sensors 7 ₁ and 7 ₂ detect the rotation speeds N _1D and N _2D of the roll drive motors 3 ₁ and 3 ₂ ,
Also the horizontal / vertical load cells 8 _1, the rolling rolls 2 ₁ horizontal roll total load P _H1D, and detects the vertical roll Average Load P _V1D, those detection values are read into the correction value calculating circuit 5 in a predetermined sampling cycle . In the circuit 5, based on these detected values and the values already stored, the equation (13)
It calculates a rotational speed correction value △ N _2D of the roll driving motor 3 ₂ of subsequent rolling mills from and supplies the speed setting / correcting circuit 6.
In speed setting / correcting circuit 6, the speed correction value supplied from the speed correction value calculating circuit 5 △ N based on _2D, the rotational speed of the roll driving motor 3 ₂ target rotational speed _{N 2D '(= N 2 D} - △ N
As the _2D), to control the motor driving circuit 4 _2. This makes it possible to compensate for the tension fluctuation caused by the temperature drop of the material to be rolled.

In the above embodiment, the ratio N _C = N _2C / N _1C of the rotation speeds of the _two roll drive motors 3 ₁ , ₃₂ is calculated at “center lock-on”, and the speed correction value calculation circuit 5 The rotation speeds N _1C and N _2C are stored in the memory as they are, and in the “central portion FTC”,
These rotation speeds may be substituted into equation (13) for calculation. Further, in the above-described embodiment, when the material to be rolled reciprocates several times between them using two rolling mills to form a roll, the former stage and the latter stage of the rolling mill are switched depending on the moving direction of the material to be rolled. . Therefore when the material to be rolled is moved from the rolling rolls 2 ₁ in the rolling rolls 2 ₂ directions (odd path direction), the rolling rolls 2 ₁ horizontal roll total load P _H1C,
P _H1D and vertical rolls Average Load P _V1C, requires the detection of P _V1D, when the above described moves in the opposite direction (even pass direction) of the rolling rolls 2 ₂ roll horizontal roll total load P _H2C , P _H2D , and the average vertical roll load P _V2C , P _V2D need to be detected, and therefore, depending on the odd pass direction and the even pass direction, the horizontal / vertical load cell 8 is required.
_1, 8 ₂ either it is sufficient only one of the operation. Alternatively, both the horizontal / vertical load cells may be operated simultaneously, and only one of them may be selectively read into the speed correction value calculation circuit 5 according to the odd pass direction and the even pass direction. further,
When rolling is performed using three or more rolling mills, rolling mills requiring speed correction are sequentially shifted as the material to be rolled moves, and accordingly, the rolling rolls of the appropriate rolling mills are accordingly changed. Naturally, the horizontal roll sum load and the vertical roll average load are detected and read into the correction value calculation circuit 5.

[0016]

According to the present invention, as described above, a temperature change occurs in the longitudinal direction of the material to be rolled, and the deformation resistance increases, whereby tension occurs in the material to be rolled interposed between the stands. Even so, a correction is made so that the speed of the subsequent rolling mill is also reduced, so that the tensionless rolling is maintained. Therefore, according to the present invention, it is possible to obtain a shaped steel bar and a steel bar having small tolerances.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram for explaining a configuration of a conventional example.

[Explanation of symbols]

1 the rolled material 2 _1, 2 ₂ rolling rolls 3 _1, 3 ₂ roll drive motor 4 _1, 4 ₂ motor drive circuit 7 _1, 7 _2-speed sensor _81, 82 horizontal / vertical load cell

Claims (1)

(57) [Claims] In a rolling system having at least a first and a second universal rolling mill, in a tension control method for rolling a material to be rolled in a tensionless state, the material to be rolled is moved from a first universal rolling mill to a second universal rolling mill. 2 in the direction of the universal rolling mill, and the first and second roll drives of the first and second universal rolling mills in a state where the leading end of the material to be rolled is bitten by the second rolling mill. While detecting and storing the rotation speeds N _1C and N _2C of the motor,
A storage step for detecting and storing the horizontal roll sum load P _H1C and the vertical roll average load P _V1C of the rolling rolls, wherein the material to be rolled is further moved in the direction from the first universal rolling mill to the second universal rolling mill. Until the rear end of the material to be rolled out of the first universal rolling mill,
And the rotation speeds N _1D and N _{2D of} the second roll drive motor, and the horizontal roll sum load P of the rolling rolls of the first rolling mill.
The _H1D and vertical rolls Average Load P _V1D detected at a predetermined sampling period, a correction value △ N _2D of the rotational speed of the second roll driving motor, following expression ## EQU1 ## △ N _2D ≒ N _2D -N _1D N _2C / N _1C × [1 + 2 ⁻¹ K} (P _H1C −P _H1D ) / (a + bW _U1 ) / t _W1 ′ + (P _V1C −P _V1D ) / c / t _f1 ′} where K is The constants a, b, and c are constants related to the rigidity of the rolling mill W _U1 is the roll width t _W1 ′ of the first rolling roll, the average web thickness t _f1 ′ when passing through the first rolling roll is The rotation speed of the second drive motor is N _2D − △ N, obtained from the average flange thickness when passing through the first rolling roll.
_A method for controlling tension between rolling stands, comprising: a correction step of correcting to _2D .