JPH0938703A - Method for controlling looper in finish-rolling mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent upward warping at the time of biting and tail narrowing down at the time of rolling up the tail part by executing a control at a fixed position with a necessary looper angle for the biting till passing the tip part of a strip through a rolling mill at the outlet side adjoined on the looper and controlling the angle to the roll-up of the tail part from the looper angle during rolling before rolling up the tail part of the strip to the necessary angle at a fixed position. SOLUTION: At the time of biting the tip part of the strip 1 to work rolls 3 of a Fi+1 stand 5 after passing through the looper 6, the looper 6 is controlled to the stationary position having the necessary looper angle to biting the strip 1 to the work rolls 3 in the Fi+1 stand 5. Thereafter, a tension control together with a looper height control are executed so that the tension of the strip 1 between stands becomes a prescribed value according to a tension detector till passing through a F1 stand as the rolling mill at the adjacent outlet side, and the looper angle is lowered so as not to jump the tail part of the strip having the necessary angle to the roll-up of the tail part from the looper angle during rolling before the roll-up of the strip 1, and the looper is the same level as the pass line to prevent the jumping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a looper control method for a finish rolling mill in a rolling mill having loopers arranged between stands.

[0002]

2. Description of the Related Art Conventionally, in a hot strip mill, a slab heated in a heating furnace is rolled by a rough rolling mill to a predetermined thickness, and then continuously rolled by a finishing rolling mill to a predetermined product thickness, and then hot rolled by a hot run table. It is transported and wound by a winder to be manufactured as a hot coil. On this occasion,
While the tension between strips is controlled by the looper between the stands of the hot strip mill to improve the dimensional accuracy of strip thickness, strip width, etc. There is no adjustment method for the looper angle when it bites into the stand and when the tail end slips past the front stand and passes, and the looper angle should be the same angle that can handle both tip and tail passes. I had no choice but to say that it was not always optimal.

As a countermeasure, for example, Japanese Patent Publication No. 61-27.
As disclosed in Japanese Patent No. 124, in a looper control method for a rolling mill, in which a looper disposed between stands is controlled to control the tension between the stands of the strip, when the looper is started up, that is, when the strip and the looper are Before the collision, at the end of the looper angle where the looper angle starts height control, the looper is started up by the looper angle control that controls the speed of the looper drive so that the angular velocity of the looper rises to a predetermined value. Is equal to or higher than the looper angle at which the height control is started, the looper looper that performs the looper height control that controls the speed of the rolling mill drive device so that the looper angle becomes a predetermined value together with the looper angular velocity control. A control method is disclosed.

[0004]

However, in the prior art such as Japanese Patent Publication No. 61-27124 mentioned above, the control of the looper angle in the threading from the time the head of the strip is bite to the time when the strip comes out. Method, especially the tip,
There is no description about the tail end, and in general, the leading end waits at the mechanical stopper position, and the trailing end dropout is to allow the strip to pass while falling to the mechanical stopper.
That is, when the plate tip passes, the looper roll is generally set higher than the pass line to prevent flaws. If you let it slip out in this state, for example, 1.2
In the case of a thin threaded plate having a thickness of about mm, there is a problem that the tail end of the plate tends to jump up, leading to problems such as squeezing of the tail end.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and passes through at the optimum looper angle at the time of biting at the tip and passing through the tail at the tail end, thereby making The present invention provides a looper control method for a finish rolling mill, which prevents warping in the case of tailing and tail squeezing at the time of trailing, and reduces the fluctuation of tension between stands during stripping to improve strip stripability. . The gist of the invention is, in a rolling mill in which a looper is arranged between stands, a fixed position control is performed to a looper angle necessary for biting until the passing of the rolled material on the exit side where the leading edge of the threaded material is adjacent to the looper, The looper control of the finishing rolling mill is characterized by controlling the looper angle during rolling before slipping out to a position required for slipping out and adjusting the pass line at the time of biting with a looper or a variable stopper. On the way.

[0006]

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a looper control device of a hot finish rolling mill according to the present invention. FIG. 1 (A) shows a state in which the looper roll is raised above the pass line to some extent, and FIG. 1 (B) shows a state in which it is arranged at the same position as the pass line. As shown in FIGS. 1 (A) and 1 (B), F _i, each having a work roll 2
In a finish strip mill of a hot strip mill comprising stand 4 and F _{i + 1} stand 5, strip 1 is F _i
Rolling is performed while applying tension by a looper 6 arranged between the stand 4 and the F _{i + 1} stand 5. The looper 6 is driven by a looper drive motor 7, and the strip 1 is tensioned by the torque generated by the looper drive motor 7.

The work roll 2 of the F _i stand 4 is driven by a rolling mill drive motor 8. In such a finishing mill, when the sheet passing the tip of the strip 1 is rolled by the work rolls 2 of F _i stand 4, when writing bite the work rolls 3 F i _{+ 1} stand 5, F i _{+ 1} stand A rolling load signal is generated in the load cell 9 arranged in 5,
A signal is applied to the looper drive motor control device 11 from the mill bite signal generator 10, and a torque command is issued from the looper drive motor control device 11 to the looper drive motor 7 via the torque control circuit 12. The looper 6 stands up and raises the strip 1.

On the other hand, during steady rolling, the looper drive motor control device 11 controls the torque of the looper drive motor 7 via the torque control circuit 12 by the signal of the tension detector 13 installed on the looper 6, so that the stripping is performed. The rolling mill drive motor control device 15 controls the number of revolutions of the rolling mill drive motor 8 in accordance with the strip tension control for keeping the inter-stand tension of 1 to be a predetermined value and the signal of the looper angle detector 14 so that the looper angle is predetermined. The looper height control for adjusting the value to a certain value is also performed to make the tension between the stands of the strip 1 constant and the looper angle constant to improve dimensional accuracy and rolling workability. It is a thing. Reference numeral 16 is a side guide.

With such a structure, when the tip of the strip 1 passes through the looper 6 and then bites into the work roll 3 of the F _{i + 1} stand 5, the looper 6 has a steady looper angle that is necessary for biting. Control strip 1 to F
_I bite into the work roll 3 of the _{i + 1} stand 5. After that, the stand tension control and the looper height control are performed together so that the tension between the stands of the strip 1 reaches a predetermined value according to the tension detector until it passes through the adjacent F _i stand which is the rolling mill on the outgoing side. , The strip 1 jumps up from the looper angle during rolling before slipping out by lowering the looper angle so that the tail end of the plate, which is the angle required for slipping out, does not jump up and is in the same position as the pass line. Is to prevent.

FIG. 2 is a diagram showing the relationship between the hot finish rolling stand No and the looper angle according to the present invention. As shown in this figure, the strip tips have rolling stands F ₁ to F _1.
Looper angle between the case and the tip mill stands F ₂ to F ₃ between _2, F _{1on ~F} in during rolling process
_2on is installed in a steady position and is controlled to a high position in _F2on to _F3on . On the other hand, in F1off to _F3off , which are in the _trailing edge state, the looper tail end is prevented from jumping up by sequentially lowering the looper angle from the steady position.

FIG. 3 is a block diagram showing a looper control of a hot finish rolling mill according to another embodiment of the present invention.
FIG. 3 (A) shows a state in which the looper roll is set higher than the pass line to some extent, and FIG. 3 (B) shows a state in which it is arranged at the same position as the pass line. 3A and 3B are the same as those in FIG. 1 in principle. According to this strip biting signal, the fixed position is not controlled by the looper control, but a variable stopper is used separately. After this, the looper 6 enters the normal control, and the stopper 18 is prepared for the position where the trailing edge is removed. Therefore, when the looper 6 falls down before slipping out of the hip, the variable stopper hits and the angle becomes necessary for slipping out of the hip, and the slipping out can be performed.

FIG. 4 is a view showing the state of biting the roll bite. In FIG. 4, (A) shows a case where the roll bite bite approach angle enters from the lower side, and empirically tends to warp upward, and (B) shows a roll bite bite approach angle enters from the upper side. Empirically, it is easy to warp. From the viewpoint of sheet passing property, an upward warp is more likely to cause a trouble, and the trouble can be prevented by adjusting the approach angle so that it slightly enters from the upper side. This approach angle slightly changes depending on the upper and lower pass lines of the front and rear stands. As shown in FIG. 5, (A) is approaching from the lower side, but (B) controls the looper angle to change the approach angle. This is an example of adjustment. That is,
FIG. 5 is a diagram showing the relationship between the looper angle and the entry angle of the rolled material.

[0013]

As described above, according to the present invention, as compared with the conventional case where no fine looper control is performed at the time of biting and slipping out of the buttocks, warp and It has become possible to prevent problems due to jumping up.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a looper control device of a hot finish rolling mill according to the present invention,

FIG. 2 is a diagram showing a relationship between a hot finish rolling stand No and a looper angle according to the present invention,

FIG. 3 is a block diagram showing the configuration of a hot finish rolling mill in a looper control according to another embodiment of the present invention.

FIG. 4 is a diagram showing a roll bite biting condition,

FIG. 5 is a diagram showing a relationship between a looper angle and an approach angle of a rolled material.

[Explanation of symbols]

1 strip 2, 3 work roll 4 F _i stand 5 F _{i + 1} stand 6 looper 7 looper drive motor 8 rolling mill drive motor 9 load cell 10 mill bite signal generator 11 looper drive motor controller 12 torque control circuit 13 tension detection Device 14 Looper angle detector 15 Rolling mill drive motor controller 16 Side guide 17 Servo valve 18 Stopper

Claims (1)

[Claims] 1. In a rolling mill in which a looper is arranged between stands, a fixed position control is performed at a looper angle required for biting until the leading end of the strip material passes through the rolling mill on the exit side adjacent to the looper, and before the slippage of the strip material occurs. A looper control method for a finish rolling mill, comprising controlling a fixed position from a looper angle during rolling to an angle required for slipping out and adjusting a pass line at the time of biting with a looper or a variable stopper.