JP3394663B2 - Speed control method of finishing mill in endless rolling - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control method for a finish rolling mill in endless rolling of hot rolling.

[0002]

2. Description of the Related Art In conventional batch rolling in which sheet bars are rolled one by one, as shown in FIG. 4, the leading end of the plate passes through a finish rolling mill or is wound around a winding device, and at the same time, a delivery side plate of the finish rolling mill. After increasing the speed, rolling is performed at a steady speed that is possible within the range of the temperature control of the strip or the rolling mill, and the output strip speed is reduced by the time the tail end of the strip exits the finishing mill to finish rolling. The strip that has passed through the machine is cooled by a run-out table and then wound by a winding device.

In batch rolling, rolling is performed at a delivery plate speed of a finish rolling mill at the plate tip of about 700 to 800 mpm. This is to prevent the tip of the plate from jumping (waving) when passing over the runout table. Regarding the tail end of the plate, the tail end prevents the plate from jumping after passing through the finish rolling mill, and the tail end is struck by a trumpet roll or an apron attached thereto by centrifugal force in the winding device. This is to prevent tearing.

By the way, a plurality of sheet bars are joined to each other by a joining machine on the entry side of the finishing rolling mill, the joining sheet bars are continuously rolled by the finishing rolling mill, and then the joining strips which have passed through the finishing rolling mill. After cooling with a run-out table, it is cut with a strip shear, and in endless rolling where the cut strip is wound with a winding device, since the plates are joined and continuous until they pass through the strip shear, The problem of waving of the plate tip other than the first plate is eliminated.

Also, regarding the tearing of the tail end of the strip, the output strip speed of the finish rolling mill is 1000 to 1200 mpm due to various technological developments (for example, the winding method in the endless rolling described in JP-A-6-198331). Up to 1200 mpm even at the time of cutting the plate with a strip shear in front of the winding device.

Under these circumstances, in the endless rolling, a method is adopted in which the finishing strip rolling speed of the finishing rolling mill is set at a constant speed of 1000 to 1200 mpm. It has become possible to dramatically improve temperature accuracy such as temperature (CT).

[0007]

However, in such a conventional endless rolling, in the case of rolling the entire length at a constant speed of 1000 to 1200 mpm for the exit strip speed of the finish rolling mill, particularly in the thin rolling of 1.6 mm or less, Even if there is an effect that the time from the trailing edge of the preceding material leaving the finishing rolling mill to the biting of the trailing material leading edge into the finishing rolling mill is 0 seconds, the total tonnage cannot be earned and the productivity cannot be improved sufficiently. There is.

Therefore, in the operation of the endless rolling, the cutting speed in front of the winding device, which restricts the rolling speed on the delivery side, and the joining speed on the entry side of the finishing rolling mill are taken into consideration, depending on the finished strip thickness. It is important to maximize the side rolling speed.

The present invention has been made on the basis of such technical background. In claim 1, while satisfying the cutting speed limitation of the joining strip by the strip shear before the winding device, it is the maximum in other areas. An object of the present invention is to provide a speed control method for a finish rolling mill in endless rolling, which can accelerate the exit rolling speed to a sufficient extent to improve productivity in thin strip rolling.

According to a second aspect of the present invention, while satisfying the limitation of the cutting speed of the joining strip by the strip shear before the winding device and the limitation of the joining speed of the sheet bar by the joining machine at the entry side of the finishing rolling mill, the other regions It is an object of the present invention to provide a speed control method for a finish rolling machine in endless rolling, which can maximize the exit rolling speed to sufficiently improve the productivity in thin strip rolling.

[0011]

In order to achieve the above object, a speed control method for a finish rolling mill in endless rolling according to a first aspect of the present invention is to bond a plurality of sheet bars to each other by a bonding machine and to bond the bonded sheets. The bar is continuously rolled by a finish rolling mill, then the joining strip that has passed through the finish rolling mill is cooled on a run-out table, then cut by a strip shear, and then the cut strip is wound by a winding device. In the endless hot finish rolling method described above, while the joint portion of the joining strip is located between the finishing mill and the strip shear, the speed limit at the time of cutting the joining strip by the strip shear is satisfied. Is characterized in that the delivery side plate speed of the finish rolling mill is reduced, and after the cutting is completed, the delivery side plate speed is increased.

According to a second aspect of the present invention, there is provided a speed control method for a finish rolling mill in endless rolling, wherein the sheet bar is joined by the joining machine while the exit strip speed is increased after the cutting of the joining strip is completed. When the entry side plate speed of the finish rolling machine is higher than the joining speed of the sheet bar by the joining machine, the exit side plate speed of the finish rolling machine satisfies the speed limit at the time of joining by the joining machine during the joining. The output side plate speed is increased or maintained after the joining is completed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic view of an endless rolling facility for explaining a speed control method of a finish rolling mill in endless rolling, which is an example of an embodiment of the present invention, and FIG. 2 illustrates a speed pattern of endless rolling according to the present invention. FIG. 3 is a graph for explaining the speed pattern of endless rolling performed by changing the plate thickness.

In FIG. 1, reference numeral 1 is a heating furnace, and the slab 2 supplied from the heating furnace 1 onto the rolling line is roughly rolled by a rough rolling mill 3 into a sheet bar 4, which is sequentially processed by the rough rolling mill 3. The roughly rolled sheet bars 4 are conveyed at a predetermined speed and are joined to each other in the longitudinal direction by a joining machine 5. The plurality of sheet bars 4 joined by the joining machine 5 become a joined sheet bar 6 and are continuously finish-rolled by the finishing rolling machine 7, and after passing through the finishing rolling machine 7, become the joining strips 8. After the joining strip 8 is cooled by the run-out table 9, the strip shear 1
The strip 11 cut at 0 is wound up alternately by the two winding devices 12a and 12b.

Here, in this embodiment, in the operation of endless rolling, in order to maximize the productivity, the cutting speed of the joining strip 8 is limited by the strip shear 10 before the winding device 12a and finish rolling is performed. The exit side plate speed v of the finish rolling mill 7 is reduced so as to satisfy the joining speed limit of the sheet bar 4 by the joining machine 5 on the entrance side of the machine 7, and otherwise the exit side plate speed v is set to the maximum speed v _max ( In the case of a thin product, the speed is increased to about 1400 to 1700 mpm).

The cutting speed of the joining strip 8 by the strip shear 10 is usually 1 regardless of the plate thickness.
It is possible up to about 200 mpm. Therefore, the cutting point set at or near the joint is the finish rolling mill 7.
Every time a predetermined position between the strip shear 10 (including the inside of the finish rolling mill 7) is passed, the exit side plate speed v of the finish rolling machine 7 is reduced from the maximum speed v _maX to about ₁₂₀₀ mpm, and the exit plate after the cutting is completed. The speed v is increased to the maximum speed v _maX (see FIG. 2).

Specifically, a joint detection sensor (not shown) is arranged at a predetermined position between the finish rolling mill 7 and the strip shear 10, and a controller (based on the detection signal obtained by the sensor). (Not shown) sends a speed command to the finishing mill 7 to satisfy the cutting speed limit (1200 mpm).
Deceleration correction is performed so that the controller finishes the finishing mill 7 based on the coiler winding completion detection signal after cutting.
The speed command is corrected to the maximum speed v _maX by correcting the speed command with respect to.

On the other hand, regarding the joining speed limitation of the sheet bar 4 by the joining machine 5, the thickness H ₀ and the speed V ₀ of the joining sheet bar 6 on the entry side of the finish rolling machine 7 and the thickness of the joining strip 8 on the exit side of the finishing rolling mill 7 are limited. Since the relationship between the height h and the speed v, H ₀ V ₀ = hv, is satisfied, the outlet plate speed v is obtained by the following equation.

[0019]   v = H₀V₀/ H ... (1) Here, the joining strip 8 by the strip shear 10
When the output side plate speed v is increased after the completion of cutting,
Plate speed v is maximum speed v_maXInput side plate speed
V₀Is the joining speed V of the sheet bar 4 by the joining machine 5._jSame as
If it is smaller than one, use the above-mentioned strip shear 10.
If only the cutting speed limitation of the joining strip 8 by
Sufficient, but the maximum speed v_maXSometimes the incoming plate speed V₀Contact
Total speed v _jIf it becomes larger, the joining strip 8
After cutting is completed, the exit plate speed v is changed to the maximum speed v_maXUp to
Then, the seat bar 4 is moved for a predetermined time (truck stroke).
It becomes impossible to join inside.

Therefore, when the entrance side plate speed V ₀ becomes larger than the joining speed v _j at the maximum speed v _maX (V _j
<V ₀ ) takes into consideration the joining speed limitation in addition to the above-mentioned cutting speed limitation, and as shown by the chain double-dashed line in FIG. The _output side plate speed v is temporarily stopped at the speed value obtained by the following equation without increasing the speed to v _{max, and} then increased to the maximum speed v _max or held at the speed value.

V = H ₀ V _j / h (V _j <V ₀ ) ... (2) Specifically, the controller is a sheet speed meter (not shown) provided on the exit side of the finish rolling mill 7. The output side plate speed v after the completion of the cutting of the joining strip 8 based on the obtained detection signal
It is judged whether or not the speed is increased, and when it is judged that the speed is increased, a preset joining speed V _j and a plate speed meter provided on the entrance side of the finishing rolling mill 7 are determined. (Not shown), the inlet side plate speed value V ₀ is compared and calculated, and when V _j <V ₀ , a plate thickness gauge (not shown) arranged on the inlet side of the finish rolling mill 7 is shown. ), The joining sheet bar thickness value H ₀ , the joining strip thickness value h and the joining speed value V _j obtained by a plate thickness gauge (not shown) arranged on the exit side of the finishing rolling mill 7. Based on the formula (2), the speed value v considering the joining speed limitation is calculated and the speed command for the finishing rolling mill 7 is corrected to the speed value v. After the joining is completed, the exit side of the finishing rolling mill 7 is exited. The finish rolling mill 7 based on a detection signal obtained by a plate speed meter (not shown) provided in the
The _output side plate speed v is returned to the maximum speed v _maX by increasing the speed command of the speed command v.

As described above, in this embodiment, the cutting speed limit of the joining strip 8 by the strip shear 10 is satisfied, and the outgoing side plate speed is increased when the outgoing side plate speed v is increased after the cutting of the joining strip 8 is completed. When v becomes the maximum speed v _maX and when the entry side plate speed V ₀ becomes larger than the joining speed V _j of the seat bar 4 by the joining machine 5,
In addition to the cutting speed limit, the joining speed limit is also satisfied, and the delivery side plate speed v can be maximized in other regions, so that the rolling time is shortened and the productivity in thin rolling is sufficiently improved. Can be improved.

The plate thickness gauges and plate speed gauges on the inlet side and outlet side of the finish rolling mill 7 are not limited to these sensors, and it goes without saying that there are various alternative methods.

[0024]

[Example] FIG. 3 shows a finish plate thickness of 1.6 mm → 1.2 mm →
An example of the speed pattern of endless rolling when changing to 1.6 mm is shown. Here, the rolling speeds of the first to third rollings are all set so that the entry side plate speed V ₀ is lower than the joining speed V _j , and therefore the control is performed in consideration of the above-mentioned joining speed limitation. Absent. The sheet bar thickness H ₀ is 32 mm.

The first piece has a finished plate thickness of h = 1.6 mm.
Since the leading end of the plate is the same as in the conventional batch rolling, the plate is passed at the exit side plate speed v = 750 mpm and wound around the winding device 12a, and after the winding, the exit side plate speed v is increased to 1100 mpm. In the case of a slab having a length of 8 to 10 m, the tail end is inserted into the joining machine 5 on the entry side at the time when the tip of the plate is wound around the winding device 12a. Here, the joining speed V _j of the joining machine 5 is set to 60 mpm, and the exit side plate speed v is set so that the entrance side plate speed V ₀ is smaller than the joining speed V _j . From the equation (1), V ₀ = hv / H ₀ = 1.6 × 1100/32 = 55mp
m <V _j = 60 mpm Next, when the joint passes through F1 of the finish rolling mill 7, the delivery side plate speed v is reduced to the cutting speed. The deceleration to the cutting speed does not necessarily have to be turned on at F1 and may be performed immediately before the strip shear 10.

After cutting by the strip shear 10, when the second plate winds around the winding device 12b, the delivery side plate speed v is immediately increased. The second plate has a finishing plate thickness of h = 1.2 mm, and even if the outlet plate speed v is increased to 1500 mpm, the inlet plate speed V ₀ of the finishing rolling mill 7 is V ₀ = hv / H ₀ from the equation (1). = 1.2 × 1500/32 = 56.2
Since 5 mpm <V _j = 60 mpm and the bonding speed is V _j or less, no problem occurs.

Next, when the second joined portion reaches the finishing rolling mill 7, the delivery side plate speed v is reduced to the cutting speed, and the strip shear 10 cuts at or near the joined portion, and again the delivery side plate speed. accelerate v. This is repeated if the number of joints is large.

In this example, the maximum speed of the 1.6 mm material is set to 1100 mpm and the joining speed limitation on the entry side of the finishing rolling mill 7 is eliminated. However, as shown by the broken line in part A of FIG. It is also possible to increase the speed from 1100 mpm.

[0029]

As is apparent from the above description, according to the invention of claim 1, while satisfying the cutting speed limitation of the joining strip by the strip shear, the exit side plate speed is maximized in other regions. Since the rolling speed can be increased, the rolling time can be shortened, and the productivity in the thin rolling can be sufficiently improved.

According to the invention of claim 2, in addition to the invention of claim 1, when the output side plate speed reaches the maximum speed at the time of increasing the output side plate speed after completion of cutting of the joining strip, When the side plate speed is higher than the joining speed of the sheet bar by the joining machine, the exit side plate speed can be maximized in other regions while satisfying the joining speed limit in addition to the above cutting speed limit. The effect of shortening the rolling time and being able to sufficiently improve the productivity in thin rolling is obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an endless rolling facility for explaining a speed control method of a finish rolling mill in endless rolling, which is an example of an embodiment of the present invention.

FIG. 2 is a graph for explaining a speed pattern of endless rolling according to the present invention.

FIG. 3 is a graph diagram for explaining a speed pattern of endless rolling performed by changing the plate thickness.

FIG. 4 is a graph for explaining a speed pattern of conventional batch rolling.

[Explanation of symbols]

4 ... Sheet bar 5 ... Joining machine 6 ... Joining sheet bar 7 ... Finishing rolling machine 8 ... Joining strip 9 ... Run-out table 10 ... Strip shear 11 ... Strip 12a ... Winding device 12b ... Winding device v ... Delivery side plate speed V ₀ … Inlet plate speed V _j … Joining speed

Continuation of the front page (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (58) Fields investigated (Int.Cl. ⁷ , DB name) B21B 37/00-37 / 78 B21B 1/00-1/46

Claims (2)

(57) [Claims] 1. A plurality of sheet bars are joined together by a joining machine, the joined sheet bars are continuously rolled by a finish rolling mill, and then the joining strip that has passed through the finishing mill is cooled on a run-out table. In the endless hot finish rolling method in which the strip is cut by a strip shear and then the cut strip is wound by a winding device, a joint portion of the joint strip is located between the finish mill and the strip shear. In the meantime, the output side strip speed of the finishing rolling mill is reduced so as to satisfy the speed limit when the joining strip is cut by the strip shear, and the output side strip speed is increased after completion of the cutting. Control method of finishing mill in endless rolling. 2. When the sheet bar is joined by the joining machine while the exit side plate speed is being increased after the completion of cutting of the joining strip, the entry side plate speed of the finish rolling machine is determined by the joining machine. When the joining speed of the sheet bar is greater than, the exit plate speed of the finishing rolling mill is reduced during the joining so as to satisfy the speed limit at the time of joining by the joining machine,
The speed control method for a finish rolling mill in endless rolling according to claim 1, wherein the exit side plate speed is increased or maintained after the joining is completed.