JP2013193121A - Rolling method of rolled material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling method of a rolled material leading to efficient production by reducing material loss in manufacturing.SOLUTION: A rolling method of a rolled material is a rolling method of a rolled material W which introduces the rolled material W rolled in a hot rolling process to a cold rolling process and manufactures a product plate material. In regards to rolling in the hot rolling process, a thickness and/or width of a tail edge part of the rolled material W is set to be smaller than a thickness and/or width of a center part, and rolling in the hot rolling process is conducted.

Description

  The present invention relates to a rolling method capable of reducing material loss in a rolled material when the rolled material is hot continuously rolled and then cold rolled to produce a product plate material.

Conventionally, product plate materials such as thin steel plates and thin aluminum plates are manufactured by rolling a rolled material through a hot rolling process and a cold rolling process.
As shown in FIG. 1 (a), in the hot rolling process, rolling is performed by a hot rolling mill having a plurality of rolling stands, and the rolled material is reduced to a predetermined size, and then the take-up reel (TR) ) To form a coil. This coil is stored in a coil yard or the like, and waits to be transported to the next cold rolling process.

As shown in FIG. 1 (b), the coil introduced into the cold rolling process is rolled by a cold rolling mill having a plurality of rolling stands, and the rolled material is reduced to a thickness as a product plate material. .
At this time, as shown in FIG. 2, the coil installed on the take-up reel (POR) is not usually automatically wound around the take-up reel, and each rolling stand of the cold rolling mill is manually operated by an operator. Pass the pass line, deflore, etc., and wind it around the take-up reel. Then, after confirming that it is surely wound around the take-up reel, the rolling speed is gradually increased to perform rolling by each rolling stand, and the rolling speed is increased to switch to the automatic rolling mode. Then, after the rolling is in a stable state, automatic control such as sheet thickness and tension starts operation.

  As is apparent from the above, in the cold rolling process, control is not performed at all until various automatic controls are operated, and in severe cases, rolling may not be performed. For this reason, the dimension of the tip of the rolled material (cold rolled tip) until the start of automatic control is completely different from the target dimension, and as a result, it becomes a non-standard product, that is, off-gauge and must be discarded. I do not get. This cold-rolled tip is a portion corresponding to a hot-rolled tail end (tail end of the rolled material in the hot rolling process), and extends to about several tens of meters.

  By the way, many automatic control techniques suitable for performing hot rolling or cold rolling have been developed. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-334511) is known for hot rolling. . This patent document 1 describes a tail end plate thickness control apparatus for a hot rolling mill that performs rolling by passing a rolling material through a plurality of finishing stands. = 2, 3, 4,...) The position of the rolled material immediately below the n-th stand is tracked from the speed of the finishing stand, and the thickness is measured when this tracking point reaches the finishing stand exit side thickness gauge. Means for measuring deviation, means for determining a correction amount based on the plate thickness deviation, and means for correcting the plate thickness increase amount by this correction amount and controlling the plate thickness of the rolled material tail end. An apparatus for controlling the thickness of the tail end of a hot rolling mill is disclosed.

  On the other hand, for cold rolling, Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-1118048) discloses a plurality of rolling stands and an apparent roll gap change amount associated with a change in rolling load with a predetermined proportional gain. A rolling control device that is applied to a tandem rolling mill having a control unit that controls a roll gap for each rolling stand, and controls the thickness of a material to be rolled, and gain adjustment that adjusts the proportional gain according to a rolling speed A rolling control device comprising means is disclosed.

JP 2000-334511 A Japanese Patent Laid-Open No. 2007-118048

The off-gauge of the cold-rolled tip (the tip of the rolled material in the cold rolling process) described above is always generated when rolling with a cold rolling mill and cannot be eliminated. It is also difficult to shorten the length. Therefore, in order to reduce manufacturing loss as a whole of the rolling process, it is advantageous to reduce the loss of material by reducing the thickness of the tip of the rolled material as much as possible.

  However, the techniques disclosed in Patent Literature 1 and Patent Literature 2 do not disclose guidelines or technical ideas for solving this problem. In the first place, Patent Document 1 discloses a sheet thickness control technique in the hot rolling process, and Patent Document 2 discloses a sheet thickness control technique in the cold rolling process, both of which are hot rolled. It does not disclose the technology of sheet thickness control in the entire rolling process including the process and the subsequent cold rolling process.

  Therefore, in view of the above problems, the present invention appropriately controls the plate thickness at the end of the rolled material in the entire rolling process including the hot rolling process and the subsequent cold rolling process, thereby producing a material at the time of manufacture. It aims at providing the rolling method of the rolling material which reduces loss and leads to efficient production.

In order to achieve the above-described object, the present invention takes the following technical means.
That is, the rolling material rolling method according to the present invention is a rolling material rolling method for producing a product sheet material after introducing the rolled material rolled in the hot rolling step into the cold rolling step, Regarding rolling in the hot rolling process, the thickness and / or width of the tail end of the rolled material is set to be smaller than the thickness and / or width of the central part, and then in the hot rolling process. It is characterized by performing rolling.

Preferably, the length of the tail end portion of the rolled material in which the plate thickness and / or the sheet width is set small is set to a length corresponding to the tip portion of the rolled material in the cold rolling process.
Preferably, the length of the tail end portion of the rolled material in which the sheet thickness and / or the sheet width is set to be small is a portion on the tip side of the rolled material and where the sheet thickness control is not applied in the cold rolling process. It should be the corresponding length.

Preferably, regarding the rolling in the hot rolling step, the plate thickness and / or plate width at the center of the rolled material may be reduced stepwise to the plate thickness and / or plate width at the tail end of the rolled material.
Preferably, regarding the rolling in the hot rolling step, the plate thickness and / or plate width of the rolled material may be continuously reduced to the plate thickness and / or plate width of the tail end of the rolled material.

  By using the rolling method of the rolled material according to the present invention, in the entire rolling process including the hot rolling process and the subsequent cold rolling process, the thickness of the end of the rolled material is appropriately controlled, at the time of manufacture. Material loss can be reduced, and efficient production of product plate material can be achieved.

It is a figure which shows the whole structure of a rolling process. It is the figure which showed typically the condition at the time of the rolling start in a cold rolling process. It is the figure which showed the mode of plate | board thickness change. It is a figure which shows the simulation result using the rolling method of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
FIG. 1 schematically shows a rolling process of the present embodiment, that is, a hot rolling process (rolling using the hot rolling mill 1) and a subsequent cold rolling process (rolling using the cold rolling mill 2). It is shown as an example.

As shown in FIG. 1A, the hot rolling mill 1 includes a plurality of rolling stands 3 and a take-up reel 5 (TR).
The rolling stand 3 includes a pair of upper and lower work rolls 6 that roll the rolled material W and a pair of upper and lower backup rolls 7 that support the work roll 6. Based on a command from the control unit 8, the gap amount of the work roll 6 of the rolling stand 3 can be changed by a reduction mechanism (not shown). Further, the work roll 6 can freely adjust the rotational speed based on a command from the control unit 8. The control unit 8 is configured by a process control, a PLC, or the like, and controls the thickness of the rolled material W that is hot-rolled. A thickness gauge 9 that detects the thickness of the rolled material W is provided on the exit side of the final rolling stand 3.

In this hot rolling mill 1, the rolled material W passes through a plurality of rolling stands 3 to be rolled into a product plate having a desired plate thickness, plate width, and plate crown, and is taken up by a take-up reel 5. Introduced into the cold rolling process.
As shown in FIG. 1 (b), the cold rolling mill 2 used in the cold rolling process unwinds the rolled material W from a plurality of rolling stands 3 and wound coils and introduces them into the rolling stand 3. An unwinding reel 4 (POR) and a take-up reel 5 (TR) for winding the rolled material W after being rolled by a plurality of rolling stands 3 into a coil shape are provided.

  The rolling stand 3 includes a backup roll 7 that supports the work rolls 6 of the upper and lower work rolls 6. The gap of the work roll 6 of the rolling stand 3 can be changed by a reduction mechanism. A thickness gauge 9 that detects the thickness of the rolled material W is provided on the exit side of the final rolling stand 3. A looper (not shown) is provided between the rolling stand 3 and the rolling stand 3, and the tension between the rolling stands 3 can be detected by this looper.

In this cold rolling mill 2, the rolled material W is cold-rolled by passing through a plurality of rolling stands 3 to become a product plate having a desired plate thickness, plate width, and plate crown, and the take-up reel 5 It is wound up by.
In the following description, the tail end portion of the rolled material W in the hot rolling process is referred to as “hot rolled tail end HB”, and the steady portion (intermediate portion) of the rolled material W in the hot rolling process is “ It is called a “hot-rolled steady part”. The tip of the rolled material W in the cold rolling process is referred to as “cold rolling tip CT”.

  By the way, as described in detail in “Problems to be Solved by the Invention”, in the cold rolling process, the cold-rolled tip portion CT is wound around the unwinding reel 4 to prepare for the start of rolling. At this time, the cold-rolled tip CT is not usually automatically wound around the take-up reel 5, but is manually wound by an operator and passed through each rolling stand 3 and wound around the take-up reel 5 by several turns. Will be. Then, after confirming that it is surely wound on the take-up reel 5, the rolling speed is gradually increased while rolling by each rolling stand 3, and the rolling speed is increased to switch to the automatic rolling mode. Then, after the rolling becomes stable, automatic control of sheet thickness, tension, and the like is started.

  As is apparent from this, in the cold rolling process, there is a case in which the control does not operate at all until various automatic controls are operated, and in severe cases, the rolling is not performed. For this reason, the cold-rolled tip CT is completely different from the target dimension, resulting in an off gauge. This off gauge is inevitably generated when rolling in the cold rolling mill 2 and cannot be eliminated, and it is difficult to shorten the length of the off gauge part. .

So, in this embodiment, in the control part 8 with which the hot rolling mill 1 was equipped, it sets and rolls the plate | board thickness of the hot-rolling tail end part HB so that it may become thinner than the plate | board thickness of a hot-rolling regular part. Thus, the plate thickness of the cold-rolled tip portion CT to be discarded is made as thin as possible to reduce material loss and to reduce manufacturing loss as a whole rolling process.
That is, the control unit 8 of the hot rolling mill 1 controls the roll gap of the rolling stand 3 to be narrowed when the rolling of the hot rolled tail end HB is performed at the end of the hot rolling process, Control is performed so that the thickness of the hot rolled tail end portion HB becomes the “plate thickness lower limit value”.

  The “plate thickness lower limit value” applied to the hot rolled tail portion HB is preferably as small as possible (thin plate thickness) in order to reduce material loss. However, the thickness should be such that no inconvenience occurs in the subsequent cold rolling process. For example, even if the operation of passing each rolling stand 3 of the cold rolling mill 2 and winding the take-up reel 5 by several turns is performed reliably, and the rolling speed is increased at the start of rolling, the rolling material W It should be thick enough not to cut or meander.

In addition, it is preferable that the length (off gauge length lower limit value) of the hot-rolled tail end portion HB is equal to or longer than the length corresponding to the cold-rolled tip portion CT (L or L or more in FIG. 2).
By the way, in the hot rolling process, various methods are conceivable regarding the change from the plate thickness of the hot-rolled steady portion to the plate thickness of the hot-rolled tail end portion HB. In the present embodiment, the following two will be described. .
First, as shown in FIG. 3A, the plate thickness (plate thickness target value) at the hot-rolled tail end portion HB is reduced from the hot-rolled steady portion to a step shape (step shape). However, the plate thickness at the hot rolled tail end portion HB cannot be set to a limit value (for example, plate thickness of 0 mm). The plate thickness target value can be reduced depending on the process conditions that do not cause plate shape disorder, plate breakage and rolling trouble, mechanical constraints determined by the rolling equipment, and constraints based on the plate-passability of the cold-rolled tip CT. It is possible to determine the minimum level.

  By building a hot rolling model that takes these into consideration and performing offline calculation in advance, it is possible to perform offline calculation before feeding. Further, since the offline calculation accuracy is determined depending on the model accuracy, it is considered that the learning function between the rolled materials W is effective in order to compensate for the modeling error. At that time, since the material strength differs depending on the product type, the target value is calculated in advance for each material strength, and is stored in the control unit 8 as a table, and when the rolling material W is rolled. Reads the value from the table value and corrects the table value according to the dimensions (rolling result) of the product plate material. For example, when the length of the cold-rolled tip CT (off-gauge length lower limit) is longer than the initially assumed value, learning is performed so that the thickness of the hot-rolled tail HB can be reduced earlier. For example, exponential smoothing may be performed.

By the way, even if the plate thickness of the hot rolled tail end HB is obtained as described above, if the plate thickness is suddenly changed at a certain point in time of the hot rolled tail end HB, the mass balance between the rolling stands 3 is rapidly changed. Therefore, there is no denying the possibility of leading to rolling trouble.
Therefore, as shown in FIG. 3B, it is effective to apply rolling in which the plate thickness is continuously changed (slowly in a slope shape). This rolling is taper rolling (the thickness target value is changed to a taper shape).

  However, by adopting this taper rolling, the effect of reducing material loss may be reduced. In order to reduce the amount of material loss, the taper angle α can be increased, but the rolling becomes unstable. Conversely, if the taper angle α is reduced, rolling is stabilized, but the amount of material loss increases. By using the taper angle α as an operating variable, the optimum value of the taper angle α can be obtained by solving an optimal problem in which the material loss amount and rolling stability (for example, tension fluctuation and thickness fluctuation) are evaluated functions.

However, since this is a complicated non-linear problem, a solution can be obtained by performing a grid search on the target taper angle α based on a rolling simulator. Moreover, considering not only the stability of the hot rolling process but also the stability of the cold rolling process, which is a subsequent process, the evaluation function can realize a more stable rolling with less trouble for both.
FIG. 4 shows a simulation result when the above-described sheet thickness control (rolling method of rolled material) is performed.

As shown by the broken line in FIG. 4, the thickness of the outlet side of the conventional hot rolling is substantially constant even in the hot rolled tail end portion HB (the thickness is controlled so as to be substantially constant). )
On the other hand, when the plate thickness control of the present invention is used, a plate (L or L or more in FIG. 2) corresponding to the cold-rolled tip portion CT to which the plate thickness control is not applied in the cold rolling process. The thickness gradually decreases, and reaches the plate thickness lower limit that is the plate thickness that does not cause a rolling trouble on the last side of the hot-rolled tail portion HB (the first side of the cold-rolled tip portion CT). That is, the plate thickness control is performed so that the plate thickness of the hot rolled tail end portion HB is thinner than the plate thickness of the hot rolled steady portion in all regions of the hot rolled tail end portion HB.

By doing so, the amount of material loss at the off-gauge that is inevitably generated in the cold rolling process can be reduced as much as possible, leading to an improvement in product yield, that is, efficient production. it can.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

For example, in the present embodiment, regarding the rolling in the hot rolling process, an example is disclosed in which the “plate thickness” of the hot rolled tail end portion HB is set to be thinner than the “plate thickness” of the hot rolled steady portion. The factor to be changed is not limited to the plate thickness. The “plate width” of the hot rolled tail end portion HB may be set to be narrower than the “plate width” of the hot rolled steady portion. Even by narrowing the plate width, the amount of material loss that inevitably occurs can be reliably reduced. In addition, regarding the plate width, it is essential to set the plate width value (not less than the plate width lower limit value) that does not cause meandering or breaking of the plate during rolling.

  Regarding the rolling in the hot rolling process, the “sheet thickness” and “sheet width” of the hot rolled tail end HB are set to be smaller than the “sheet thickness” and “sheet width” of the hot rolled steady part at the same time. May be.

DESCRIPTION OF SYMBOLS 1 Hot rolling mill 2 Cold rolling mill 3 Rolling stand 4 Unwinding reel 5 Winding reel 6 Work roll 7 Backup roll 8 Control part 9 Sheet thickness meter HB Hot rolled tail end CT Cold rolled leading end W Rolled material

Claims (5)

After introducing the rolled material rolled in the hot rolling step into the cold rolling step, a rolling method for rolling the rolled material to produce a product plate material,
Regarding the rolling in the hot rolling step, the thickness and / or plate width of the tail end portion of the rolled material is set to be smaller than the plate thickness and / or plate width of the central portion, and then the hot rolling step The rolling method of the rolling material characterized by performing rolling in.   The length of the tail end portion of the rolled material in which the plate thickness and / or the sheet width is set to be small is a length corresponding to the tip portion of the rolled material in the cold rolling process. The rolling method of the rolling material described in 2.   The length of the tail end portion of the rolled material in which the sheet thickness and / or the sheet width is set to be small is the length corresponding to a portion on the tip side of the rolled material and where the sheet thickness control is not applied in the cold rolling process. The method for rolling a rolled material according to claim 1 or 2, wherein the rolling method is performed.   Regarding the rolling in the hot rolling process, the thickness and / or width of the central portion of the rolled material is reduced stepwise to the thickness and / or width of the tail end of the rolled material. The rolling method of the rolling material as described in any one of Claims 1-3.   Regarding rolling in the hot rolling step, the thickness and / or width of the central portion of the rolled material is continuously reduced to the thickness and / or width of the tail end of the rolled material. The rolling method of the rolling material as described in any one of Claims 1-3.

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