JP2003071506A - Hot rolling mill train and hot rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot rolling mill train and a hot rolling method capable of being compatible with improving production efficiency of hot rolling and with securing wall thickness accuracy at an inexpensive cost of equipment. SOLUTION: One or more cross mills are provided in the downstream of a Steckel mill, and a metal plate is tandem-rolled using the Steckel mill and the cross mill in the last pass by the Steckel mill. Further, a thermometer to measure the temperature of the metal plate after the last pass of the rolling by the Steckel mill is provided and, based on the temperature data of the metal plate measured by the thermometer, vertical roll gap openings and vertical roll cross angles are set up.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hot rolling equipment train,
And a hot rolling method using the same.

[0002]

2. Description of the Related Art Hot rolling of a metal strip (hereinafter also referred to as a metal plate) is carried out at a temperature of 1000 ° C. to 100 to 100's.
After heating to ℃, it is extracted on a hot rolling line and rolled by rollers while being conveyed. The hot rolling line is roughly classified into (1) a type called a Steckel mill shown in FIG. 9 (a) and (2) a type called semi-continuous shown in FIG. 9 (b), which includes a rough rolling mill 14 and finish rolling. Machine 1
6 are separately provided, the rough rolling mill 14 performs reciprocal rolling, and the finish rolling mill 16 performs unidirectional rolling. (3) A type called 3/4 continuous shown in (c), Plural types of rough rolling mills 14 (in many cases, R1 to R
4 of 4), some of them (often 1 of R1)
Reciprocal rolling, and the remaining R2 to R4 are unidirectionally rolled (including not only three of the four unidirectional types, but also two of three unidirectional types) 3/4)), and so on.

In the figure, 10A to 10C are heating furnaces and 1
2 is a material to be rolled (metal lump, metal plate), 13 is a descaling device, 15 is a heat retention furnace (also called furnace coiler), 1
8A and 18B are coilers.

What is important in hot rolling is to perform the rolling with higher efficiency to increase the production amount, and to make the metal sheet to be rolled thin as much as possible over the entire length to the target thickness. Is to do rolling.

Of the three types of rolling mills shown in FIGS. 9 (a), 9 (b) and 9 (c), the type shown in FIGS. 9 (b) and 9 (c) is excellent in ensuring high production efficiency, It is also excellent in finishing the thickness of the rolled metal sheet uniformly (securing the thickness accuracy), but the problem is that the installation cost of the hot rolling line equipment is high.

On the other hand, the type called the Steckel mill shown in FIG. 9 (a) has an advantage that the installation cost of the equipment is relatively small.

An example will be given. On the order group of raw metal ingots to be supplied to the hot rolling line, the average unit weight is large and small, and the presence of high-temperature and long-time heating materials, etc. With the semi-continuous type shown in 9 (b), the equipment cost is about 90 billion yen, and the production amount is 13 to 2 per month.
If it is 50,000 tons and the 3/4 continuous type shown in FIG. 9C, the facility cost is about 150 billion yen and the production amount is 25 to 50 per month.
In contrast to the 10,000 tons, the Steckel mill type shown in FIG. 9 (a) produces a production amount of at most 30,000 tons per month and, at the same time, has a plate thickness accuracy of the rolled metal sheet due to the reason described below. While there is a problem in securing the
There is an advantage that it will be about 0-40 billion yen. Above all, this Steckel mill is a very rational facility for the production of a variety of products such as high value-added stainless steel, which requires a relatively small amount of production compared to ordinary steel.

The Steckel mill has a finish rolling mill 16 sandwiched between it and a heat-retaining furnace (furnace coiler) 15 on its inlet and outlet sides.
And the metal plate is reciprocally rolled by the finish rolling mill 16,
During both the forward pass and the backward pass, heat is retained (or heated) while being wound in the furnace coiler 15.
To be done. Therefore, since the finish rolling machine 16 can reduce the temperature drop of the metal plate during reciprocating rolling, it is possible to prevent an increase in load during rolling, and it is not necessary to introduce an expensive rolling machine capable of withstanding a high load.

Now, regarding the above-mentioned problem of plate thickness accuracy, FIG.
This will be described with reference to 0. In the Steckel mill, between the finishing rolling mill 16 and the furnace coiler 15 on the entry / exit side is 7 to 1
There is a distance of about 0 m, and after rolling in each pass, the part of the tail end of several m does not enter the furnace coiler, and this part becomes lower in temperature and harder than other parts. Therefore, if no special measures are taken in the next pass rolling in this part, the plate thickness will be locally thicker and the uniformity of the plate thickness in both the length direction and the width direction will deteriorate. become. By the way, because of the reciprocating rolling,
This cold part can be at both the tip and tail of the metal plate. However, since the temperature decrease rate does not increase so much while the plate thickness is still thick during the initial pass stage during finish rolling, the influence of this local low temperature part on the plate thickness accuracy is not significant. However, especially in the case where the plate thickness becomes considerably thin during finish rolling and becomes less than 3 mm, and
(Final-1) At the tip part of the final pass that does not enter the furnace coiler when the pass is completed, the influence of this local low temperature part on the plate thickness accuracy becomes apparent. This is because the temperature drop rate becomes faster and it will never be heated in the furnace coiler again.

At this point, at the tail end of the final path, (final-
2) There was still a low temperature part locally due to the fact that it did not enter the furnace coiler when the pass was completed,
The coldness is not as great as the final pass tip. While doing the (final-1) and final pass rolling,
Because it is heated in the furnace coiler for a considerable time, the temperature difference with other parts gradually disappears.

As described above, the problem of the local low temperature portion at the tip of the final pass depends on the plate thickness. As a result, the low temperature of the same portion is several hundreds of degrees Celsius, and the thickness of the same portion is the other portion. Even if it leads to a serious problem that the deviation from the range becomes several 100 μm, which may deviate from the range specified in JIS tolerance as the plate thickness accuracy of the product, the compensation control of this part by the rolling mill A known gauge meter A
If the method such as GC is used as it is, the same method locks the rolling load at a certain point in the leading edge region of the metal plate, and thereafter, the deviation from the locked rolling load is multiplied by an appropriate gain to open the upper and lower roll gaps. On the principle of controlling the degree, the rolling load is locked on when the plate thickness of the tip of the metal plate deviates by several hundred μm in some cases as described above, rather than the control for ensuring the plate thickness accuracy, It can also lead to the result of being completely useless.

The reason why the tail end of the metal plate cannot be put into the furnace coiler after rolling will be described below. For example, by unwinding the tail end of the metal plate in the previous pass until it enters the heat-retaining furnace 15 and heating it (disclosed in Japanese Patent Laid-Open No. 59-191503), the end of the final pass of the metal plate is unwound from the furnace coiler. During the time required for the metal sheet to be bitten into the finish rolling mill 16, the metal plate is eventually cooled and the temperature drops. This is because in order to ensure smooth biting of the metal plate into the finish rolling mill 16, the passing speed of the metal plate at that time must be reduced (in many cases, after the biting, acceleration is performed). ). In particular, when the plate thickness is reduced to less than 3 mm, the passing speed of the metal plate at that time must be reduced for the purpose of ensuring smooth biting into the finish rolling mill 16. Moreover, as described above, the thinner the metal plate, the faster the temperature drop rate. These two synergistically increase the degree of local temperature drop at the tip of the final pass of the metal plate.

If it is assumed that the metal plate is wound and held in the furnace coiler until completion of compensation heating for this local temperature drop, the time required for holding (heating) after winding is several minutes. The productivity is less than half, considering that it takes about 10 to 60 seconds at most for one pass of rolling, depending on the plate thickness within the same plate thickness range and the size of the order weight. It will be significantly worse. For this reason, rather than compensating and heating the local low-temperature part, rolling is completed with the tail end of the metal plate of the previous pass left outside the furnace coiler, and rolling is performed in the previous pass in order to roll the next pass as soon as possible. It is concluded that it is rational to leave the tail end at a position as close as possible to the finish rolling mill 16 so that the tail end can be easily bited in the next pass.

[0014]

As described above, the conventional Steckel mill has two problems.

[0015] One problem is the improvement of production efficiency. As described above, the installation of the semi-continuous or 3/4 continuous hot rolling line is several times the equipment cost of the Steckel mill, and therefore its installation is not easy. In some cases, due to economic growth and other changes in circumstances, the required production volume may gradually increase over time,
Although it is a Steckel mill with a small amount of premise production, rolling mills that can secure a reasonably high production efficiency compared to the conventional type of Steckel mill, including the case of taking measures to increase production efficiency such as additional installation and modification of equipment There was a strong demand for it.

The other is the problem of ensuring the plate thickness accuracy. This is true not only in the length direction of the metal plate but also in the width direction.

As described above, after the second pass of the Steckel mill, since the temperature at the number m of the tip of the metal plate is lower and harder than the other parts, the rolling load of the same part is locally higher than that of the other parts. Become higher. When the rolling load increases, the opening of the upper and lower roll gaps increases, and the plate thickness of the same portion increases. Also, due to the higher rolling load, the bending of the roll in the plate width direction during rolling of the same part also becomes larger, and as a result, the plate crown (in the term of those skilled in the art, the amount of protrusion of the plate thickness in the plate width direction) Also grows. Derivatively, the shape of the metal plate also becomes edge extension (also referred to as ear wave) in which both widthwise end portions are longer than the center portion.

When the plate thickness of the metal plate is in the initial pass stage in a plurality of passes and is still relatively thick, that is, in the first half stage of reciprocal rolling, the above-mentioned temperature difference and the load fluctuation caused by it are small. However, as the plate thickness becomes thinner, that is, in the latter half of the reciprocal rolling, particularly in the part that did not enter the furnace coiler in the (final -1) pass, the local rolling load during the same part rolling increases in the final pass. This leads to load fluctuations and plate thickness fluctuations when viewed over the entire length of the metal plate. In particular, when the product thickness is as thin as less than 3 mm (final -1) to the final pass, it is necessary to obtain a certain reduction ratio. It is not possible to roll a metal plate into a flat shape with only conventional general actuators such as, and if it becomes a scallop, and if it is the (final -1) pass, rolling of the next final pass is performed. There is also a problem that the robot will bounce when it is bitten in, making it difficult to bite it. On the other hand, it is conceivable to reduce the load variation by reducing the rolling reduction, but this leads to the problem that the number of passes increases and the production efficiency further decreases.

As described above, there has been a problem of how to improve the production efficiency and to secure the accuracy of the plate thickness in order to achieve both at the same time and with the inexpensive equipment.

[0020]

The present invention has been made to solve various problems as described above, and has a Steckel mill and one or more cross mills arranged downstream of the Steckel mill. It is a characteristic hot rolling equipment line. Further, the present invention further sets the upper and lower roll gap openings and the upper and lower roll cross angles of the cross mill from the thermometer for measuring the metal plate temperature after the final pass of rolling by the Steckel mill and the metal plate temperature measured by the thermometer. It is a hot rolling equipment row characterized by having means.

Further, the present invention is a hot rolling method for a metal sheet, which is characterized in that the metal sheet is tandem-rolled by using a Steckel mill and one or more cross mills, and further, the metal sheet after the final pass of the Steckel mill rolling. Based on the result of measuring the temperature, it is preferable to set the upper and lower roll gap opening of the cross mill and the upper and lower roll cross angle, and further,
Before the final pass of rolling by the Steckel mill, the upper and lower roll gap opening and the upper and lower roll cross angle are set individually for each of the metal plate part inside the heat retention furnace and the metal plate part outside the heat retention furnace, It is preferable to change the upper and lower roll gap openings and the upper and lower roll cross angles at the boundary between the two during rolling.

Here, the mill refers to a rolling mill.

Simultaneous rolling of one rolled metal sheet by a plurality of rolling mills is called tandem rolling. In tandem rolling, the production efficiency is improved as compared with the case where the Steckel mill rolls alone. For example, consider the case of hot rolling using a Steckel mill and one rolling mill arranged downstream thereof. Then, from constraints such as rolling load and shape, products that require 6 passes for finish rolling are assumed. In a Steckel mill, which is a reciprocating rolling mill, such a product is generally manufactured in 7 passes since it is convenient in terms of transportation to finish rolling in odd-numbered passes in principle, but the hot rolling of the present invention is used. Using the equipment train, it is possible to manufacture with 5 passes of the Steckel mill followed by 1 pass of tandem rolling. Further, for example, considering hot rolling in the case of a steckel mill and an equipment row having two rolling mills arranged downstream thereof, when manufacturing a product requiring 7 passes of finish rolling, 7 passes of the steckel mill are used. It is also possible to reduce the number of passes and share the remaining two passes on the tandem rolling mill side. In these cases, the production efficiency is improved by several 10%. Alternatively, a total of 8 to 9 including 7 passes of rolling with a Steckel mill and 1 to 2 passes of rolling by a rolling mill arranged downstream.
By rolling in a pass, the rolling reduction of each pass of the Steckel mill can be decreased little by little, thereby increasing the rolling speed of each pass and improving the production efficiency.

In the present invention, rolling is performed by a rolling mill disposed downstream after rolling by the Steckel mill.
A cross mill with a high crown control capability is used for the rolling mills arranged downstream, so even if there is a large change in rolling load due to the temperature decrease at the tip end, as shown in Fig. 3, the upper and lower roll cross angles run. The mechanical crown of the roll can be kept small by changing the roll crown between the upper and lower roll cross angles during running as shown in FIG. Can be prevented from becoming excessively large, and a metal plate having a good shape can be manufactured. Further, before the final pass rolling by the Steckel mill, as shown in the image in FIG. 4, during the rolling, for each of the tip of the metal plate outside the furnace coiler and the tail of the metal plate inside the furnace coiler. The upper and lower roll gap openings may be controlled to be changed. Since FIG. 4 is an image diagram, the local low-temperature portion is exaggerated and drawn longer, but when there are a plurality of cross mills in tandem, any stand may be considered. In FIG. 4, the length corresponding to the region where the temperature locally drops at the tip, and the length corresponding to the region where the temperature locally drops at the tail end.

The upper and lower roll gap openings and the upper and lower roll cross angles, which change during rolling in the cross mill, should be stored as a table in a computer after accumulating actual data and patterning with the product sheet thickness as a key. To Then, when the rolled metal sheet corresponding to the key comes next, an appropriate pattern can be predicted and set. Based on this information, the settings of the upper and lower roll gap openings and the upper and lower roll cross angles are changed during running in the longitudinal direction during rolling. As a result, even with a metal plate having a large temperature difference in the longitudinal direction, the plate thickness can be controlled with high accuracy.

Of course, what is finally desired to be secured is a uniform plate thickness in the longitudinal direction and a uniform plate thickness in the width direction of the metal plate. However, the present invention is not limited to the above-mentioned example, and may be an appropriately modified control mode.

For example, what is stored as a pattern is not the values of the upper and lower roll gap openings or the upper and lower roll cross angles themselves, but instead the rolling load per unit width, and the width of the metal plate to be rolled. In addition to the product obtained by multiplying the product by the mill elongation calculation, mechanical crown, transfer rate, and genetic coefficient calculation,
During rolling of the upper and lower roll cross angles, a change pattern may be calculated, or, for example, the temperature of the tip of the metal plate may be measured with a thermometer to determine the upper and lower roll gap angles and the upper and lower roll cross angles during rolling. It does not depart from the gist of the present invention to take a control form such as correcting the change pattern by calculation.

Alternatively, as described below, the temperature of the entire length of the metal plate is measured by a thermometer to determine the change pattern of the upper and lower roll gap openings and the upper and lower roll cross angles during rolling. It is possible to secure a uniform plate thickness in the longitudinal direction and a uniform plate thickness in the plate width direction.

The temperature of the metal sheet and the length of the locally low temperature portion have the same rolling schedule (various settings such as the upper and lower roll gap opening of each pass of each rolling mill, the upper and lower roll cross angles, and the rolling speed). However, since it varies to some extent, if the length of the low temperature part at the tip end, which is peculiar to the Steckel mill rolling, is grasped, the hardness (deformation resistance) of the metal plate and the fluctuation of rolling load in the next pass will be as described below. The influence of the above on the plate thickness can be further suppressed as compared with the case where the upper and lower roll gaps and the upper and lower roll cross angles are set as a pattern with the product plate thickness as a key as described above. In other words, there is a large temperature difference in the longitudinal direction by measuring the temperature of the entire length of the metal plate and applying this to the change of the running distance of the upper and lower roll gaps during rolling and the change of running distance of the upper and lower roll cross angles during rolling. Even with a metal plate, the plate thickness accuracy can be further improved in both the longitudinal and width directions, and the shape can be controlled to be flat.

Although the technique of the present invention has been described as a hot finish rolling mill in which a steckel mill and a cross mill are arranged in tandem, the mill type of the steckel mill is not particularly limited, and 4hi (quadruple rolling mill), 6hi ( A six-fold rolling mill), work roll shift, or any other type may be used, and of course, the Steckel mill itself may be a cross mill. Further, the cross mill may be a pair cross in which a backup roll and a work roll are paired up and down and crossed at the same angle, or a work roll alone. Further, not only a device for crossing the rolls but also a roll bending device for bending the rolls in the width direction of the metal plate (also referred to as a roll bender. A work roll bender for applying a force for axially bending the rolls to the chocks at both ends of the work rolls. Even if the rolling mill also has a so-called type), it does not depart from the gist of the present invention. However, it is important for the content of the present invention that at least one rolling mill arranged downstream of the Steckel mill is a cross mill, regardless of the rolling mill. It is worth noting here that the technique of the present invention adds a cross mill to a relatively small hot rolling facility having only one steckel mill stand to significantly increase the production efficiency and to reduce the thickness of products. This means that it is also effective when newly manufactured.

[0031]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(First Embodiment) FIG. 1 schematically shows the equipment and control mechanism of the first embodiment suitable for carrying out the present invention. In FIG. 1, 1 is a table roller, 10A is a heating furnace,
11 is a crop shear, 12 is a material to be rolled (metal plate), 1
3 is a descaling device, 14 is a rough rolling mill, 15 is a furnace coiler, 16A and 16B are finish rolling mills, 18A and 18
B is a coiler, 19 is a cooling device, 20 is a drive device, 2
Reference numeral 1 is a control device, and 22 is a computer. Finishing mill 16A
When the furnace coiler 15 on both the inlet side and the outlet side is set as a set with the above sandwiched therebetween, this portion constitutes a Steckel mill type rolling mill.

Thickness 200-270 mm, width 600-20
The metal plate 12 in the form of a block of 00 mm is heated to 100 in the heating furnace 10A.
It is heated to 0 to 1300 ° C. After that, as an example, the thickness 2
It is assumed that a metal plate having a width of 00 mm and a width of 1200 mm is heated at 1200 ° C.

The metal plate 12 that has been heated is descaled by the descaling device 13. This descaling device normally uses a high-pressure water jet of 10 to 30 MPa for the metal plate 12.
Although not shown in FIG. 1, it is also injected from the lower side of the line toward the back surface of the metal plate 12 from the upper side of the line toward the front surface of the metal plate.

The metal plate 12 after descaling is the rough rolling machine 1
No. 4, usually 5 to 9 passes of reciprocal rolling, 20 to 40
It is thinly stretched to mm. At this time, the width of the metal plate 12 is 1200 m, which is the original width, by an edger rolling machine (not shown).
It is rolled while being restrained so as not to spread extremely beyond m. Further, the rolls of the rough rolling mill 14 are almost always cooled by the cooling water during the operation, and are prevented from being seized with the high temperature metal plate 12. Cooling water is generally supplied from a cooling water supply system (not shown) and is supplied by being jetted toward the roll surface by a nozzle or the like.

Table 1 (example of SUS304) shows an example of the sheet thickness schedule of each pass of rough rolling. The diameter of the work roll was 1000 mm.

[0037]

[Table 1]

Now, as an example shown in Table 1, the following description will be made assuming that the thickness is extended to 20 mm.

The metal plate 12 after the rough rolling is cut off by the crop shear 11 at a tip of about several hundred mm in length, and conveyed to the finishing rolling mill 16A.

The finish rolling mill 16A is also a mechanism for reciprocating rolling. First, the first pass rolling will be described. Prior to the tip of the metal plate 12 being caught in the roll of the finishing rolling mill 16A, the tip of the metal plate 12 was descaled by the descaling device 13 just before the rough rolling was started. Bite into the roll of machine 16A. After biting the tip of the metal plate 12, the finish rolling mill 16A continues the function of thinly extending while transporting the metal plate 12 in the longitudinal direction by the rotation of the rolls. It is introduced while being wound up. When the tail end of the metal plate 12 passes under the crop shear 11, the tail end is also cut off by about 100 mm.

The inside of the furnace coiler 15 is maintained at a temperature of 800 to 1100 ° C., which is a hardness of a metal plate suitable for finish rolling, by a heating means (not shown). Here, as an example, description will be given below assuming that the temperature is maintained at 900 ° C.

When the tail end of the metal plate 12 has been rolled by the finish rolling mill 16A, the metal plate 12 is transferred to the finish rolling mill 16A in the next pass (for reciprocating transport, the transport direction is opposite to that of the first pass). To enable early and smooth biting (the tail end in the first pass above becomes the tip in the next pass), 1
In the pass, the tail end of the metal plate 12 is not wound until it completely enters the furnace coiler 15, and the tail end is finished by the finishing mill 16.
Immediately after exiting to the exit side of A, the transportation of the metal plate 12 is stopped, and the first pass finish rolling is completed. It is preferable to stop in such a state, but if it is in a situation where attention is paid to a decrease in production efficiency, it is completely denied to wind up until it completely enters the furnace coiler 15, as in JP-A-59-191503. Not something to do.

After the completion of the first pass finish rolling, the metal plate 12
When the conveyance of No. 2 is stopped, the tip of the metal plate 12 (the tail end in the first pass) is introduced into the finishing rolling mill 16A in a direction opposite to the conveyance direction described above, and the metal sheet 12 is engaged with it. Prior to that, descaling may be performed by the descaling device 13 if necessary. The cooling of the rolls is the same as in the rough rolling mill. The finish rolling mill 16A has a transport direction opposite to that of the first pass, and does not cut off the front end and the tail end by the crop shear, as in the first pass. The metal plate 12 is continuously introduced from the leading end while being wound into the furnace coiler 15 on the opposite side with the finishing rolling mill 16A sandwiched therebetween.

Thereafter, the same operation as that of the first pass is performed for the odd-numbered passes except that the tip and tail ends are not cut off by the crop shear, and the same operation as that of the second-pass is performed for the even-numbered pass. The metal plate 12 is gradually thinly extended by repeating a series of operations of performing.

In the odd-numbered pass which is the final pass, the leading end of the metal plate 12 is conveyed toward the finish rolling mill 16B starting from the state where it is not introduced into the furnace coiler 15. The switching of the transport direction is performed by a transport direction switching device (not shown). The finish rolling mill 16B should be installed as close to the finish rolling mill 16A as possible.
It is preferable for suppressing the temperature drop of the metal plate 12. As a result, in almost all cases, except when the length of the metal plate 12 is extremely short, the finish rolling mill 16A and the finish rolling mill 16B are in a tandem rolling state in which one metal plate 12 is rolled at the same time.

The finishing rolling mill 16A and finishing rolling mill 16B, the mandrel of each furnace coiler 15, the mandrel of the coiler 18A or 18B, and the table roller 1 (the drive device is omitted in the drawing) were connected to them. Through each drive device 20, the control device 21 precisely controls the uniform speed of the volume velocity (mass flow),
In order not to break one metal plate 12 that is being rolled at the same time due to excessive tension, or to be compressed and buckled to the contrary, to form a loop and be clogged between both rolling mills to make it impossible to continue conveyance. Controlled.

The metal sheet 12 thus finish-rolled is cooled to a temperature range for imparting a desired material to the product by the cooling water sprayed from the cooling device 19 and then wound into a coil by the coiler 18A. . If one coiler cannot keep up with the production pitch of the metal plate 12, another 1
The base coiler 18B is installed, and the metal plates 12 that are rolled one after another are alternately wound by both the coilers 18A and 18B.

The flow of the basic series of processes has been described above. The thickness of the metal plate as in the above example is 200 m
m, the heating temperature is 1200 ° C., the material is, for example, SUS304, and the finish plate thickness of the target product is 2.0 mm and the finish plate width is 1200 mm. The standard number of passes is that the number of passes is 7 passes and is thinly extended to a thickness of 20 mm, and the total number of passes in the finishing rolling mill 16A and the finishing rolling mill 16B is 8 passes, and is thinly extended to a thickness of 2.0 mm. Is. The sheet thickness schedule for finish rolling according to this example is shown in Table 2 below (example of SUS304). By the way, the diameter of the work roll is 650mm.
If you want to roll at a maximum bite speed of 60 mpm and roll at a speed faster than that, 4 seconds after biting,
Accelerated rolling was performed at 0 mpm / sec.

[0049]

[Table 2]

By doing so, if a total of 15 passes including 7 passes in the rough rolling mill 14 and 8 passes in the finish rolling mills 16A and 16B are performed, the target product is the metal plate 12. The finished sheet can be thinly stretched to a thickness of 2.0 mm, and in that sense, the rough rolling mill 14 is not necessarily used.
It does not have to be provided with a finishing mill 16
The required number of passes may be rolled only by A and 16B. In addition, the crop shear 11 is not an indispensable facility. Both of them are more preferable for the purpose of improving the production efficiency and ensuring the smooth biting of the finish rolling mill 16A, and therefore, the case was described as an example. The number of finish rolling mills 16B has been described as one in the above example, but it is not necessarily one and may be two or more. When a finishing rolling mill is additionally installed downstream of the existing Steckel mill, it is necessary to prevent mechanical interference with the installation area of the cooling device 19.
The number of finishing mills that can be added will naturally be limited due to restrictions on the installation space. As described above, the number of finish rolling mills 16B may be appropriately determined in consideration of the installation cost depending on the situation.

Next, how to secure the uniformity of the plate thickness in the longitudinal direction and the width direction of the metal plate 12, which is an important subject in the present invention, and its control method will be specifically described below. explain.

FIG. 2 shows an enlarged view of the vicinity of the finish rolling mill 16A. In this state, the metal plate 12 has completed (final-1) pass rolling, and the (final-1) pass tail end of the metal plate 12 is The state at the very moment when the finish rolling machine 16A leaves the roll and decelerates and then stops is shown.

First, the thickness control of the metal plate 12 in the lengthwise direction will be described. The finish rolling mill 16 shown by d in FIG.
After the completion of the A to (final -1) pass, it is first important to control the distance of the tail end stop position to be constant.

This is necessary for later controlling the upper and lower roll gap openings of the finish rolling mill 16B so as to narrow it to a locally low temperature portion, and determining how much the rolling length is to be continued. The data. If the distance d can be controlled to be constant, the finish rolling mill 16A to the furnace coiler 15
Since the machine length up to the entrance is constant, the metal plate 1 that is outside the furnace coiler 15 when the (final-1) pass is completed
The length L0 of 2 can be constant. In this L0, (final-1)
The plate thickness of the metal plate 12 after the pass is divided by the value obtained by dividing the plate thickness of the metal plate 12 after the final pass, and the value is further multiplied by the plate thickness of the metal plate 12 after the final pass by the finish rolling mill 16B. If the value obtained by dividing the product of the subsequent plate thickness is replaced by L, the upper and lower roll gap openings of the finishing rolling mill 16B should be controlled so as to be narrowed to a locally low temperature portion. Therefore, the upper and lower roll gap openings of the finish rolling mill 16B are controlled so as to be narrower than the local low temperature portion by the rolling length L.

To keep the distance d constant, APC (Au
A control called tomatic Positioning Control) is used. In the control device 21, this is the finishing rolling mill 16A,
Starting from the time when the tail end of the metal plate 12 of the previous pass has passed, for example, if the distance from the finish rolling mill 16A to the tail end is x, the square root of (d−x) is multiplied by an appropriate control gain. And outputs it as a speed command toward the mandrel of the furnace coiler 15 being wound. As a result, the metal plate 12 from which the tail end of the previous pass has passed through the finish rolling mill 16A decelerates at a constant acceleration and stops.

Next, it is determined how narrow the upper and lower roll gap openings should be. The rolling load locally increases at a locally low temperature portion of the tip portion of the metal plate 12, so that the elongation (mill extension) of the housing of the finish rolling mill 16B in the plate thickness direction locally increases, and Although the plate thickness increases, it can be predicted by calculating it with a theoretical model such as the spring constant of the mill or the temperature dependent function of the deformation resistance of the metal plate, but a simpler method can be used. Take here.

Actually, how much the thickness is increased depends on the material of the metal plate 12 after being rolled by the finish rolling mill 16B and the thickness of the product sheet. This is because (1) d is controlled to be constant as described above, (2)
The final pass, the plate thickness schedule of the metal plate 12 after (final-1) pass rolling, and the rolling speed are the same as the material of the metal plate 12 after being rolled by the finish rolling mill 16B, as in the example of Table 2 above. Assuming that the table value with the product thickness as a key is transmitted from the computer 22 to the control device 21 as data,
Since it is convenient for the control of the finish rolling mill 16B, from the start of the local temperature drop at the tip portion of the metal plate 12, the finish rolling mill 16B at the tip of the metal plate 12 starts.
The time required to start rolling by means of is determined substantially uniquely by the material of the metal plate 12 after rolling in the finish rolling mill 16B and the product plate thickness as keys, and therefore, the degree of temperature drop between them and the deformation resistance This is because the degree of rise, and the degree to which it affects the plate thickness, are essentially determined.
By the way, since the plate width has a proportional effect, the table value may be a value per unit width, and this may be multiplied by the plate width.

Therefore, as shown in the following Table 3 (example of SUS304), a table having materials and product plate thicknesses as keys is virtually provided in the computer 22, and L, ΔS, W are output to the control device 21. Then, the control device 21 controls the upper and lower roll gap openings of the finish rolling mill 16B based on this.

[0059]

[Table 3]

Here, ΔS is a quantitative value of the upper and lower roll gap openings to be narrowed with respect to the local low temperature portion of the tip of the metal plate 12, and is a value per unit width of the metal plate 12. Further, if W is the plate width of the metal plate 12, control is actually performed to change the vertical roll gap opening amount by ΔS × W.

In Table 3, if L0 = 5.0 m, t =
In the case of 2.0 mm, the plate thickness after the final pass rolling by the finish rolling mill 16A is 2.4 mm, and the plate thickness after the same (final-1) pass rolling is 2.8 mm, so L = 5.0 × 2.4 / 2.
0 × 2.8 / 2.4 = 7.0 m is obtained. Similarly, for each product plate thickness (1.5 mm, 2.
4 mm) for the finished rolling thickness schedule, t = 1.
In case of 5 mm, L = 5.0 × 2.0 / 1.5 × 2.4 /
When 2.0 = 8.0 m and t = 2.4 mm, L = 5.
0 × 2.8 / 2.4 × 3.2 / 2.8 = 6.7 m is obtained.

Since Table 3 is given as an example,
The material is only one example of SUS304, finish rolling machine 1
Plate thickness after rolling at 6B is 2.4 mm, 2.0 mm, 1.5
Only three examples of mm are shown, but in reality, data of other materials and plate thickness are also held as table values. Also, the numerical values are not necessarily limited to this example, but are merely examples.

Next, the thickness control of the metal plate 12 in the width direction will be described, but the idea is similar to the case of the thickness control in the longitudinal direction described above. That is, by using the material, product thickness and width of the metal plate 12 after rolling by the finish rolling mill 16B as keys, the metal plate 1
The upper and lower roll cross angles θ of the portion excluding the local low temperature portion of 2 and the change amount Δθ of the upper and lower roll cross angles of the local low temperature portion of the tip of the metal plate 12 are uniquely defined. Table 4 (SUS304 width 1
000 to 1300 mm), it is virtually provided in the computer 22 and outputs L, θ, θ + Δθ to the control device 21, and the control device 21 outputs the L, θ, θ + Δθ to the control device 21.
Controls 6B upper and lower roll cross angles.

[0064]

[Table 4]

Since Table 4 is given as an example, the material is only one example of SUS304, and the finish rolling mill 16B
Thickness after rolling in 2.4mm, 2.0mm, 1.5mm
There are only three examples, and the plate width is 1000 to 1300 mm.
Although only an example is shown, in fact, data of other materials, plate thickness, and plate width are also held as table values. Also, the numerical values are not necessarily limited to this example, but are merely examples.

In this manner, before the metal plate 12 is caught in the finish rolling mill 16A or 16B, each rolling condition including the thickness schedule of each pass (upper and lower of each pass of each rolling mill). Roll gap opening, upper and lower roll cross angles, rolling speed, etc. There are others and are collectively referred to as a rolling schedule).
After finishing with the entire finishing rolling mills 16A and 16B, the finishing rolling mill 16 is actually used until the metal plate 12 reaches the (final-1) pass.
Reciprocating rolling at A, and finishing mill 16A and 1 at the final pass
Tandem rolling of 6B is performed.

Now, apart from the above-described initial setting calculation before the metal plate 12 is caught in the finish rolling mills 16A and 16B, the metal plate 12 is actually used in the finish rolling mills 16A and 16B. After biting into the, the rolling load at a certain time point after rolling several meters in the length direction from the tip of the metal plate 12 as the rolling progresses with time, the rolling load not shown attached to the finish rolling mill 16B. Measured by a meter and transmitted to the control device 21, the control device 21 locks it on, continues to measure the rolling load in real time thereafter, calculates the deviation from the locked rolling load in real time, and Output what is multiplied by an appropriate gain,
It is preferable to perform gauge meter AGC control that reflects in real time on the upper and lower roll gap opening of the finish rolling mill 16B.

Similarly, for the roll bender, the metal plate 1
Rolling load is locked on at the time of rolling a few meters in the length direction from the tip of No. 2, and thereafter, the deviation from the locked rolling load is detected by the control device 21 and multiplied by an appropriate gain to obtain the roll bending force. It is also preferable to perform a control called load-interlocking control that reflects the above. Here, a few meters from the tip, as shown in the control pattern (1) in FIG. 4,
It is better to make it correspond to excluding the local low temperature portion of the tip of the metal plate 12, but similarly, the local low temperature of the tip portion of the metal plate 12 can be controlled by the procedure shown in the control pattern (2) in FIG. Rolling load is locked on at the point with the tip individually for the part and the part that is not rolled after that, and the gauge meter AGC control and the load interlocking control of the vendor are individually performed in each area. Good. In this case, the metal plate 12 corresponding to the transition between the two
It is preferable to turn off both controls in a region where the temperature and hardness of the above change transiently. Turning these controls on and off
Since the above-mentioned L is recognized in the control device, it is set by adding an appropriate timer value to it in the control device, and from the detection of the biting of the tip as the starting point, the drive device 20 rolls a constant increment length. The control device 21 performs an operation of counting the number of pulses generated each time, and counting down the above-mentioned L and the timer value by accumulating what is multiplied by the constant length increment.
This is made possible by a method called tracking.

Furthermore, as the rolling progresses over time,
With the plate thickness gauge 23 installed immediately downstream of the finish rolling mill 16B, the actual length direction thickness and width direction plate thickness, and the flatness meter 24 also provided immediately downstream of the finish rolling machine 16B, The actual flatness is measured respectively, and the control device 21
It is preferable that the actual performance data is transmitted to and the following feedback control is performed based on the actual performance data.

The control device 21 receives these performance data and (1) calculates the deviation from the target product thickness in real time based on the actual lengthwise thickness, and increments the value by a certain fixed time. Multiply by, and integrate at fixed time intervals, and multiply the integrated amount by an appropriate gain to reflect it in real time in the setting of the upper and lower roll gap openings, so that the deviation approaches zero over time. A thickness gauge monitor AGC control that performs feedback integration control (when the measurement principle of the thickness gauge is based on X-rays, it is particularly called X-ray monitor AGC control), or (2) the actual width-direction thickness Based on this, the deviation from the target product crown is calculated in real time, and the feed is performed to fine-tune the roll bender and the vertical roll cross angle to change the deviation to zero. (3) Target product flatness (in many cases, 0% which shows a completely flat state as a shape steepness) based on the actual flatness. It is a product of the metal plate 12 that the deviation is obtained by calculation in real time, feedback control is performed to change the roll bender and the upper and lower roll cross angles, and the flatness control is performed to make the deviation zero. Is preferable for ensuring the plate thickness and flatness of the entire length.

When the output of the crown control and the output of the flatness control are contradictory, the flatness of the flatness is set within the range of the crown allowable upper and lower limits separately sent as data from the computer 22 to the controller 21. One is given priority and controlled. If you want to make the crown smaller and the roll bender force reaches the upper limit of the equipment specifications, but you still want to make the crown smaller, or if you want to flatten the flatness, the roll Even if the vendor force reaches the upper limit of the equipment specifications, if you want to make the flatness still flat, change the running distance to increase the vertical roll cross angle, and conversely, to increase the crown, roll Even if the vendor force reaches the lower limit of the equipment specifications, if you still want to increase the crown, or if the flatness is flat, it is the belly extension in which the center part extends from both ends in the width direction as opposed to the ear extension. Even if the roll bender force reaches the lower limit of the equipment specifications, if you still want to flatten the flatness, change the running distance to reduce the upper and lower roll cross angles. You may be using a control called exchange.

The first embodiment is generally carried out as described above. For example, due to variations in the tip temperature of the metal plate 12, compared with the past results of metal plates of the same material and product size. If the tip temperature is low, adjust the initial settings such as setting the upper and lower roll gap openings narrower, or if the actual crown is out of the target, determine the cause by the roll profile or roll. As ascribed to the prediction error of the mechanical crown, it is also possible to re-execute and rewrite the prediction calculation of the roll profile or the mechanical crown of the roll, perform learning control of the crown, etc. Does not deviate at all.

Further, part or all of the method for ensuring the plate thickness accuracy of the metal plate described in the description of the first embodiment above may be carried out for the finish rolling mill 16A in the same manner as for the finish rolling mill 16B. The upper and lower roll cloths may be controlled only when the finish rolling mill 16A is also of the cross mill type.

[0074]

[Example 1] SUS304, plate thickness 200 mm x plate width 1
Rolling a metal block of 200 mm x plate length 7000 mm into a product size of 2.0 mm plate thickness x 1200 mm plate width,
FIG. 5A shows the distribution of the plate thickness and the shape (flatness) in the length direction when it is carried out by the first embodiment. The gauge meter AGC, the load interlocking control of the vendor, and the flatness control were used together, and the rolling load was locked on near the tail end in the longitudinal direction, avoiding the local low temperature part formed in the tip part of the metal plate. As a comparative example, FIG.
It shows in (c). By the way, in the comparative example, the X-ray monitor AG
C, load interlocking control, and flatness control are used together.

According to the present invention, regarding the plate thickness, the metal plate 1
Although there are some distribution fluctuation points at the boundary between the local low temperature part of 2 and the part excluding it, the target of ± 50 μm, which is stricter than ± 220 μm which is the tolerance of the same sized product of mild steel according to JIS It is within the precision, and it can be seen that the shape and the shape are well controlled. On the other hand, in the comparative example, there is a problem that the portions indicated by ◯ may be out of the permissible range because the plate thickness and the flatness are disturbed. Regarding the local low-temperature part, which was created due to the fact that it did not enter the furnace coiler when the (final-2) pass was completed, the low-temperature degree was not as high as the tip part of the final pass, so the plate thickness was also The flatness is not much worse than that at the tip, and can be sufficiently compensated by a gauge meter AGC or the like.

(Second Embodiment) Next, FIG. 6 schematically shows the equipment and control mechanism of a second embodiment suitable for carrying out the present invention. In FIG. 6, main constituent equipment is almost the same as that of FIG. 1 used in the first embodiment. However, the only difference is that a thermometer 17 is additionally installed and a finish rolling mill 16C is additionally installed. The point where the thermometer 17 is additionally installed will be described in detail below, but the point where the finish rolling mill 16C is additionally installed is merely an example,
It has no special meaning.

A specific method for locally compensating the thickness of the low temperature portion of the metal plate 12 in the second embodiment will be described below. The thermometer 17 measures the temperature at a constant pitch (for example, 1 mm pitch) in the length direction of the metal plate 12, and transmits each measured temperature to the control device 21 as data. The control device 21 determines the boundary between the locally low temperature portion of the tip portion of the metal plate 12 and the portion that is not to be rolled subsequently, based on the above temperature measurement data. This method will be described more specifically.

First, based on each temperature measured by the thermometer 17,
When the temperature gradient of each point in the length direction of the metal plate 12 is calculated by connecting adjacent data of each measured temperature with a straight line,
As shown in FIG. The change in absolute value of the temperature gradient becomes a polygonal line as shown in FIG. Therefore, the polygonal line is examined from the front end side to the tail end side in the transport direction of the metal plate 12, and the position corresponding to the point on the tail end side where the polygonal line intersects the threshold value is determined. It is determined that it is a boundary between a locally low temperature portion of the tip of the steel sheet and a portion that is not to be rolled subsequently. It should be noted that, here, for example, a smoothing process may be appropriately performed such that a temperature gradient at a certain point is the center and an average value of the temperature and three temperature gradients before and after that are represented as the temperature gradient at the certain point. You may

Thus, when the boundary between the local low temperature part of the tip of the metal plate 12 and the part which is not to be rolled subsequently is determined, the length from the leading edge of the metal plate 12 to the boundary is determined. Is equivalent to L in the above-described first embodiment, and the same control as the control in the first embodiment is performed.

[0080]

[Embodiment 2] According to the description of the second embodiment of the present invention, the gauge meter AGC and the load interlocking control are used together.
Locking on the rolling load is performed in the manner shown in the control pattern (2) of FIG. 4, and the result of using the flatness control and the X-ray monitor AGC together is shown in FIG. 5 (b). Compared with the result of the example of the first embodiment of the present invention shown in FIG. 5 (a), the disturbance of the plate thickness and the flatness at the portion indicated by the circle is further reduced, and good control can be performed. I understand. It is considered that this is because L can be measured accurately.

[0081]

As described above, by using the technique of the present invention, a product with high dimensional accuracy can be manufactured, and the production amount can be dramatically improved. In addition, the following effects can be obtained as a side effect. That is, since a product having good plate thickness and plate crown accuracy and a good shape can be manufactured, the yield is greatly improved. Also, since it is possible to manufacture a metal plate with a good shape, there are few rolling problems such as drawing, and the line can be maintained in an operating state with a high operating rate.
High productivity can be secured.

[Brief description of drawings]

FIG. 1 is a diagram showing a system of equipment and control for implementing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of stopping the conveyance of a metal plate in carrying out an embodiment of the present invention.

FIG. 3 is a diagram schematically showing a state in which a change in width-direction plate thickness of a metal plate can be reduced by crossing upper and lower rolls of a rolling mill.

FIG. 4 is a diagram schematically showing the change patterns of the upper and lower roll gap openings and the upper and lower roll cross angles during rolling in association with the longitudinal direction of the metal plate.

FIG. 5 is a diagram showing comparison between the execution results of the first and second embodiments of the present invention and the execution results of the comparative example.

FIG. 6 is a diagram showing a facility and a control mechanism for implementing the second embodiment of the present invention.

FIG. 7 is a temperature gradient of each point for explaining a method of determining a boundary between a local low temperature portion of a tip portion of a metal plate and a non-local portion in implementing the second embodiment of the present invention. Figure showing an example

FIG. 8 is a diagram showing an example of changes in the absolute value of the temperature gradient.

FIG. 9: Conventional Steckel mill type, semi-continuous type, 3 /
Diagram showing four continuous hot rolling lines

FIG. 10 is a diagram illustrating a problem of a conventional Steckel mill.

[Explanation of symbols]

10A, 10B, 10C ... Heating furnace 12 ... Rolled material (metal plate) 14 ... Rough rolling mill 15 ... Furnace coiler (heat retention furnace) 16, 16A, 16B, 16C ... Finishing rolling mill 17 ... Thermometer 18A, 18B ... Koira 19 ... Cooling device 20 ... Drive device 21 ... Control device 22 ... Calculator 23 ... Plate thickness gauge 24 ... Flatness meter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tosada Takechi             2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo             Saki Steel Co., Ltd. F-term (reference) 4E002 AD04 BA01 BA03 BB18 BC05                       CB07 CB08

Claims (5)

[Claims] 1. A hot rolling facility train comprising a Steckel mill and one or more cross mills arranged downstream of the Steckel mill. 2. A thermometer for measuring the temperature of the metal plate after the final pass of rolling by the Steckel mill, and the upper and lower roll gap openings and the upper and lower roll cross angles of the cross mill are set from the metal plate temperature measured by the thermometer. The hot rolling equipment sequence according to claim 1, further comprising means. 3. A method for hot rolling a metal sheet, which comprises tandem rolling a metal sheet using a Steckel mill and one or more cross mills. 4. The upper and lower roll gap openings and the upper and lower roll cross angles of the cross mill are set based on the result of measuring the temperature of the metal plate after the final pass of rolling by the Steckel mill. Hot rolling method for metal sheets. 5. Before and after the final pass of rolling by the Steckel mill, the upper and lower roll gap openings and the upper and lower rolls are individually provided to the metal plate portion inside the heat retention furnace and the metal plate portion outside the heat retention furnace. The hot rolling method for a metal sheet according to claim 3 or 4, wherein a cross angle is set and the upper and lower roll gap openings and the upper and lower roll cross angles are changed at the boundary between the two during rolling.