JPH07110363B2 - Continuous rolling method - 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 continuously rolling a plate material capable of ensuring excellent productivity, material yield and product quality.

[0002]

2. Description of the Related Art As a "method for improving productivity and reducing yield loss" in rolling a plate material, a plurality of materials to be rolled are continuously rolled while being connected to each other at the entrance side of a rolling mill. "Complete continuous rolling method" is known.
According to this completely continuous rolling method, the "time period during which rolling is stopped" during normal operation is eliminated, resulting in a significant improvement in productivity. Also, "the tip of the material to be rolled is caught in the rolling mill. ”
Since the unsteady work such as “slip through the tail end of the rolled material” is eliminated, the stripping of thickness is greatly reduced and the material yield loss can be reduced.

However, the completely continuous rolling method has the following problems. That is, if the types and conditions of the materials to be rolled that are spliced together are the same, there will be no particular problems, but when rolling materials with different types and conditions, "best for the preceding rolled material" before and after the joint. The point is that no technology has been established for continuously switching from "rolling conditions" to "optimal rolling conditions for the rolled material that follows." Therefore,
Now that the requirements for "thickness accuracy in the plate width direction" and "flatness of plate" of rolled products are becoming more and more stringent, the complete continuous rolling method for which the rolling condition switching technology as described above has not been established is classified. -Even if we tried to apply it to the rolling of materials with different conditions, we could not expect an operation that could fully utilize its advantages.

However, the present inventors who strongly recognize the advantage of the perfect continuous rolling method, which is excellent in terms of productivity and material yield, have no advantage in rolling the material having different types and conditions. We started research from various viewpoints with the aim of establishing a perfect continuous rolling method that can be applied without damage.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, rolling conditions (thickness accuracy in the width direction and flatness) that can be dealt with in an extremely short time without stopping the operation of completely continuous rolling are also used. In order to obtain the following conclusions, we first reviewed the basic technology for securing the thickness accuracy and flatness of the rolled sheet in the width direction, recognizing that switching technology is indispensable. It was

That is, the first basic technique for ensuring the thickness accuracy of the rolled plate in the width direction and the flatness of the plate is the work wheel of the rolling mill, which is "corresponding to the type and conditions". It is a means using a roll "provided with a predetermined initial crown. However, in this method, it is necessary to have a work wheel having various kinds of initial crowns corresponding to the size and material of the material to be rolled, and in addition, if there is a change in the material to be rolled, Since it is necessary to change the rolling condition to deal with it, it is not possible to respond quickly to changes in rolling conditions, and it is extremely troublesome to deal with changes in the roll profile due to roll wear and thermal expansion. It was

In recent years, however, in order to avoid the above-mentioned inconveniences, there has been proposed a "countermeasure using a rolling mill having a structure capable of changing the mechanical crown of a work wheel" as shown below. It has been devised and is the mainstream technology for rolling high quality products. A) Work roll bending method, B) VC roll method (method of changing roll crown by adjusting oil pressure or roll internal temperature), C) CVC roll method (rolling in axial direction) -A combination of upper and lower rolls that form a curved surface with a continuous change in roll diameter.
D) Roll cross rolling method (Roll cross rolling method (upper and lower work wheels are arranged diagonally to the rolling direction and crossed with each other to adjust the crown) Method of carrying out: JP-A-58-304, JP-A-58
-157504). Of these, the "roll cross rolling method" is a method that can take the largest amount of mechanical crown change of the work wheel, and is particularly noteworthy as a rolling technique when there are various types of rolled materials. Met.

However, the above-mentioned roll cross rolling method is premised on the non-continuous rolling, and the roll cross angle for setting the mechanical crown suitable for the material to be rolled is changed between the rolling work and the rolling work. In the meantime, it was carried out in the "time period when rolling is stopped (time period when rolling load is not applied)". Therefore, in roll cross rolling that is in practical use, it is necessary to perform unsteady work such as "biting of the tip of the material to be rolled" and "skipping of the tail of the material to be rolled" into the rolling mill every time the material to be rolled changes. Therefore, the problem that the thickness deviation easily occurs and the material yield loss becomes high cannot be ignored, and the dissatisfaction in terms of productivity has been pointed out.

However, in the case of this roll cross rolling, although it has not been attempted in the past, it is possible to relatively smoothly change the roll cross angle during rolling (a state in which a rolling load is applied). Was clarified by the study of the present inventors, and on the occasion that it was confirmed that it is not particularly difficult to incorporate a mechanism exhibiting such a function into the roll cross rolling mill, the complete continuous rolling was performed. "Roll cross rolling machine with the above mechanism" was applied to the method, and the rolling test of the rolled material with different types and conditions joined was repeated. If rolling is performed while changing the amount of reduction and the roll cross angle, even if the material to be rolled is "a series of materials with different types and conditions", it is possible to obtain a product of appropriate quality smoothly with the complete continuous rolling method. It is possible to obtain a stable and stable control, and if the roll roll reduction amount and roll cross angle change control are appropriate, an extremely good material yield can be secured. ”
And found a new fact.

The present invention has been made on the basis of the above findings and the like. "In continuous rolling while joining a plurality of materials to be rolled, at least one stand rolling mill of a continuous rolling mill is being rolled. The roll cross type rolling mill is capable of changing the roll cross angle, and the rolling amount of the roll cross type rolling mill at the joint position of the preceding and succeeding rolled materials is
By rolling while changing the roll cross angle from "the angle that gives the optimum amount of reduction and mechanical crown to the preceding material" to "the angle that gives the optimum amount of reduction and mechanical crown to the following material", high quality is achieved. Is characterized in that the rolled product can be manufactured with good yield under excellent productivity ", and further" when changing the roll cross angle in rolling according to the method, The reduction amount and cross angle are calculated from the dimensions (width, thickness) and material of the rolled material, and the roll clearance position adjustment time and roll cross angle adjustment time are calculated from the difference between the obtained value and that of the preceding material. The material yield can be further improved by changing the operating speed required for adjustment so that the longer one of these can be adjusted to the adjustment time of the other. ” is there.

Hereinafter, the present invention will be described more specifically with reference to exemplary drawings. FIG. 1 is a schematic diagram illustrating one example of the method of the present invention, and the equipment used is configured as follows. That is,
In the completely continuous tandem rolling mill as shown in FIG. 1, characteristically, at least one stand (one or more stands) of the continuous rolling mill group has a "roll roll angle changeable during rolling". It has a structure that incorporates a Lucross rolling mill (4).

Now, the material to be rolled is fed out from the entrance side reel (1) with its tip being ejected, and after the ejection, the joining of the tail end of the preceding material and the tip of the following material is carried out by the strip joining machine (2). Done. At this time, the strip accumulator (between the inlet section and the rolling mill is installed so that the rolling mill can continue rolling without stopping even if the strip in the inlet side section (strip to the position of the joining machine) stops running. 3) is located. When the material to be rolled (predecessor material) and the material to be rolled (subsequent material) have been joined, rolling is performed by the group of continuous rolling mills, but when the joints of the rolled material pass the roll cross mill (4). , "Roll cross angle and optimum reduction amount that gives the optimum mechanical crown to the preceding material" to "Roll cross angle and optimum reduction amount that gives the optimum mechanical crown to the following material" continuously set during rolling Changes are made.
The setting values (roll down position, roll cross angle, tension, rolling oil amount, etc.) are changed so that the "seal position" is the center for each roll stand, as shown in FIG. . Further, reference numeral 5 in the drawing indicates a running cut facility, and 6 indicates an exit side reel.

The following effects are mainly secured by such a rolling method. That is, the so-called "completely continuous rolling method" has a great effect in improving productivity of rolling work and reducing yield loss, and the "roll cross rolling method" is a work method.
Since it is possible to greatly change the amount of mechanical crown of the roll, it has a great effect on improving the plate thickness accuracy in the width direction of the rolled material and the flatness of the plate. According to the above-mentioned method according to the present invention, which is skillfully incorporated and combined, the roll cross can be performed without impairing the advantage of the complete continuous rolling method even for "a series of rolled materials formed by joining materials of different types and conditions". Rolling that takes into consideration the advantages of the rolling method can be carried out, and high-quality products can be stably and continuously rolled and manufactured under high productivity and high material yield.

Moreover, when changing the setting of the roll cross rolling mill at the joint position of the rolled material, the dimensions (width, thickness) of the rolled material
Also, the roll clearance position adjustment time and the roll cross angle adjustment time are calculated from the reduction amount obtained from the material and the difference between the front and rear materials of the roll cross angle, and the longer adjustment time is the other adjustment time. When the operation speed is adjusted so that the two values coincide with each other, the rolling material cut-off length in the setting change time zone is further reduced, and the material yield is further improved.

The control of the roll cross rolling machine in this case is preferably performed as follows. First, in the control system, a) the rolling condition is changed around the plate joint, and b) the rolling speed at the time of passing the plate joint is set to a constant low speed (of course, it changes depending on each stand). The conditions are as follows: a) The dimensions of the rolled steel strip (thickness and width at the inlet and outlet sides), material, rolling roll diameter, etc. are set in advance by the upper CPU (production instruction
The roll setting values (rolling amount, roll rolling position, roll cross angle) given from the above) are calculated in the rolling control CPU from the above conditions. Calculate and command in the procedure.

Calculation procedure 1) Find the difference between the rolling set values of the preceding material (currently rolled material) and the following material, 2) Find the "time required for setting change" based on the above difference, 3) Roll rolling position And the cross angle change time, whichever is longer, is used as the reference to determine the setting change start point (converted by the strip passing speed). 4) The roll rolling position change time and the cross angle change time are the same. So that the shorter change speed is obtained, 5) After detecting the seam of the rolled steel strip with the roll seam detector, the steel strip feed amount is tracked, and the starting point for changing the setting of the above procedure is the rolling mill. A change command and a change speed command are issued when the center is reached.

Next, the present invention will be described with reference to examples.

Example 1 As shown in FIG. 3, in a completely continuous rolling facility, a cross type mechanical crown variable rolling device was installed at # 1 to # 3 from the entrance side of a 5-stand tandem rolling mill to perform an operation test.

First, a cross angle change test was conducted in an idle state, and the time required to change the set angle was obtained. It was found that 0.8% was required to change the roll cross angle from 1 ° to 1.2 °.
I found that it took a second. Also, when the time required to change the rolling reduction was measured, it was confirmed that it took 0.12 seconds to change the setting of 0.1 mm. Next, an actual strip running test was carried out. At this time, when changing the product size: 1.2 mm thickness x 1250 mm width (predecessor material) to 0.8 mm thickness x 1480 mm width (subsequent material), use low-speed striping (passing speed: 3.75 m / sec) as the preceding material. At the boundary position with the succeeding material (with the center position at the boundary position), the cross angle setting is changed with the above change amount, and at the same time, the reduction amount change time is the time required to change the cross angle.
(0.8 sec) ”and the setting value of the reduction amount was changed to the above value, and rolling was performed (using stepwise reduction commands every 0.05 seconds). As a result, the surrounding area of the connection between the preceding and succeeding materials The cut-off amount due to dimensional anomalies including the poor flatness of the product in 2 was only 2 m.

On the other hand, when the cross angle change and the rolling reduction are separately performed at arbitrary timings, the shape defect (end) is formed especially on the succeeding material side centering on the seam (the boundary between the preceding material and the succeeding material). Partial waviness occurred, and it was necessary to cut off about 5 m. Furthermore, if the cross angle is changed after the running of the steel strip has been completely stopped, it will be calculated as a loss of about 5 m in terms of low-speed strip running length and 10 m for the setting change point passing, and It was found that the cut-off length of the unsteady part at the time of stopping / starting is about 20 to 30 m, which corresponds to the stand length.

Example 2 A test was conducted by applying the completely continuous roll cross rolling method according to the present invention to a cold rolling process of a steel sheet. Here, in the completely continuous cold rolling equipment for steel plates,
Similar to the equipment shown in Fig. 3, "roll cross type rolling mills capable of changing roll cross angle between running distances" are arranged for the three stands on the upstream side of the rolling mill group to connect the preceding and succeeding materials. Rolling tests were conducted while changing the cross angle setting and the reduction amount setting at the boundary position of. In cold rolling,
Since the plastic flow in the width direction of the steel sheet is sufficiently generated in the range of the three stands on the upstream side, by arranging the roll cross type rolling mill at this portion, the mechanical crown optimal for each rolled material can be obtained even during rolling. Was able to give. Therefore, it was confirmed that the plate thickness accuracy of the steel plate in the plate width direction can be significantly improved. Further, it was also confirmed that the cold rolling was performed under the completely continuous rolling method, so that the productivity and the yield were significantly improved as compared with the conventional type.

These effects are shown in Table 1 in comparison with a conventional example (a system in which the running of the steel strip is completely stopped and then the setting is changed).

That is, in the roll cross rolling method, the optimum cross angle can be obtained from the relationship between the amount of reduction and the strip width. From the above results, the method of the present invention shows that the amount of reduction and the cross angle at the joining point of the materials to be rolled are It is considered that the change in synchronization makes it possible to reduce the occurrence of shape defects and visually perform rolling that is almost normal. For this reason, the defective part cut-off position becomes the dimensional reference value such as plate width deviation, thickness deviation, etc., and only the cutting command (cut-off command) by the automatic dimension inspector is sufficient, reducing visual inspection by conventional operators and inspectors. Is possible.

[0023]

[Summary of Effects] As described above, according to the present invention, it is possible to perform a complete continuous rolling of a rolled material in which materials of different types and conditions are joined, and to obtain a rolled material of good quality with good productivity, This will bring extremely useful effects to the industry, such as enabling continuous production under yield.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an example of the method of the present invention.

FIG. 2 is an explanatory diagram of a condition setting value change timing in the vicinity of a joint position between a preceding material and a succeeding material.

FIG. 3 is a schematic explanatory diagram of a completely continuous rolling facility applied in an example.

[Explanation of symbols]

1 Inlet side reel 2 Strip joining machine 3 Accumulator 4 Roll rolling mill capable of changing roll cross angle between running distances 5 Running distance cutting equipment 6 Outer side reel

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiya Oi 4-53-3 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd. (72) Tsuneo Nakano 4-chome, Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture No. 22 Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Kanji Hayashi 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Works (72) Inventor Tetsuo Kajiwara, Kannon, Nishi-ku, Hiroshima Prefecture 4-6-22 Shinmachi Mitsubishi Heavy Industries Ltd. Hiroshima Research Laboratory (56) References Japanese Patent Publication Sho 59-49083 (JP, B2)

Claims (2)

[Claims] 1. In continuous rolling while joining a plurality of materials to be rolled, a roll cross angle can be changed during rolling of a rolling mill having at least one stand of continuous rolling equipment.
In addition to the roll cross type rolling mill, the rolling amount and roll of the roll cross type rolling mill at the joint position of the preceding and succeeding rolled materials
Continuous rolling characterized by rolling while changing the lucross angle from "the angle that gives the optimum reduction amount and mechanical crown to the preceding material" to "the angle that gives the optimum reduction amount and mechanical crown to the following material" Method. 2. When changing the roll cross angle of a roll cross type rolling mill, the reduction amount and the cross angle are calculated from the size and material of the material to be rolled subsequently, and the obtained value and the value of the preceding material are calculated. It is characterized in that the roll clearance position adjustment time and the roll cross angle adjustment time are obtained from the difference between them, and the operation speed required for the adjustment is changed so that the longer one of these is adjusted to the other adjustment time. The continuous rolling method according to claim 1.