JPH0433710A - Tandem mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot rolling mill that rolls a metal such as steel, particularly a metal plate, at a temperature higher than room temperature. The present invention relates to a tandem rolling mill that can reduce the thickness of a rolled material in a short time in order to reduce the drop in temperature of the rolled material.

[Prior art] When rolling a metal plate such as steel at a temperature higher than room temperature,
There are often restrictions on the appropriate temperature range. For example, when rolling a certain type of alloy steel from a 200 mm thick slab to a final thickness of 2 mm, the heating temperature must be around 1100°C due to material constraints.
Moreover, the temperature during the final rolling pass must be 900°C or higher, and in this case only a 200°C temperature drop is allowed. Even in such extreme cases, the heating temperature should be kept as low as possible to save heating energy.
On the other hand, in order to reduce the load on the rolling mill, it is desirable to complete rolling while the temperature is as high as possible.

As described above, in general, in hot rolling, an essentially important issue is how quickly the heated material to be rolled can be rolled to a predetermined thickness without decreasing the temperature of the material to be rolled. This means, for example, that when rolling thin sheets, such as 1-2 mm thick, the cooling rate will be faster, or when rolling long, but not very thin, materials, the time required to roll the entire length will increase. This is particularly important because the temperature drop during the rolling process is significant.

The most suitable form of rolling for reducing the temperature drop of the material to be rolled is to use multiple rolling mills in close proximity to each other and feed the material to be rolled in one direction. It uses a tandem rolling mill that rolls multiple locations at the same time. However, from a material with a thickness of 200 mm, 2
When rolled into a product with a thickness of [[lrn], the thickness must actually be reduced to ]/100, and the length will be approximately 100 times greater. To reduce the thickness by this amount, 13 rolling passes are required, with each rolling pass reducing the thickness by 30%. Accordingly,
If such rolling were to be carried out only by tandem rolling as described above, 11 rolling stands would be required, which would require an extremely large amount of equipment cost. In addition, since the same material to be rolled is rolled on these stands at the same time, the speed of the rolling mill that performs the first rolling pass must be approximately I/100 of the speed of the rolling mill that performs the last rolling pass. . For this reason, the speed of the first rolling mill is so slow that its work rolls cannot withstand the heat load from the heated material to be rolled.
Alternatively, the speed of the final rolling mill may be too high to be designed for, making it impossible to put it to practical use.

For this reason, the tandem rolling described above is often applied to finish rolling, in which the thickness of the material to be rolled is reduced to a certain level and then rolled to the thickness of the product. A tandem rolling mill used for finish rolling of steel plates usually consists of seven or less rolling stands, and the total thickness of the mill is usually about 30o+m, and the thickness reduction ratio is 1 in total.
It is limited to about 15 vs.

The reduction of the thickness to the level of the finishing mill is carried out by a roughing mill, which can operate independently of the finishing mill. The form of rough rolling can be classified into the following two types, and there are also combinations thereof.

One of them is called reciprocating rolling, in which a single rolling stand reciprocates the material to be rolled and performs back-rolling to a predetermined thickness of the rough-rolled material.

The other type is one in which the material to be rolled is not sent in one direction, but is rolled in a plurality of rolling stands. In this case, unlike finish rolling, the length of the material to be rolled is not that long, so it is not necessarily rolled at the same time on multiple rolling stands, but it is often simply rolled in sequence in one direction. . In this specification, only the rolling form in which the same rolled material is rolled at the same time will be referred to as tandem rolling.

Among the various types of rolling described above, as already mentioned, tandem rolling is the most commonly used rolling type in order to reduce the temperature drop of the material to be rolled. However, while tandem rolling has very high productivity when comparing the same thickness, it generally requires a large number of rolling stands, resulting in high equipment costs. For this reason, performing all of the rough rolling at the thick stage using tandem rolling using multiple stands results in unreasonably high productivity compared to rolling mills for finishing, and correspondingly, equipment costs are also unreasonably high. It's big.

An influential proposal for this purpose is, for example,
The technique disclosed in No. 8703 is known. This is 2
The material to be rolled, which is a thick steel plate, is tandem-rolled using two rolling stands close together, and if it is necessary to reduce the thickness by more than 2 baths, the material to be rolled is tandem-rolled once. This is tandem reciprocating rolling, in which the rolled material is sent in the opposite direction, tandem rolling is performed in the opposite direction, and this operation is generally repeated. The productivity of this technology, when applied to relatively thick cases, is comparable to a tandem finishing mill for thin steel plates made up of seven stunts. Therefore, if the same technology is used in a rough rolling mill for thin steel sheets, the productivity will match that of the tandem finishing mill described above, and it can be applied. In this way, the same technology can be used as a rough rolling mill for thin steel sheets, and more generally, when productivity and thickness are applicable conditions, it can reduce the temperature low f, and This is an excellent technology that does not require unreasonably large equipment costs.

In addition, in Japanese Patent Publication No. 57-7801, a tandem rolling mill was used in which an auxiliary rolling mill was installed close to the entry side of a normal rolling mill, and the first auxiliary rolling stand was opened. A technique is disclosed in which the overall thickness of the material to be rolled is significantly reduced by forcing the material to be rolled into a second conventional rolling stand. This solves the problem that when attempting to roll a relatively thick material to be rolled with a large reduction in thickness, it is difficult for the tip of the material to be caught between the upper and lower work rolls. This method is excellent in that rolling can be quickly completed by significantly reducing the thickness in one bath, and the temperature drop in the rolled material can be reduced.

[Problems to be Solved by the Invention] However, the techniques disclosed in the above-mentioned prior art still have the following problems.

First of all, multiple rolling buses in tandem rolling are
This is carried out using a conventionally known ordinary rolling stand, and since it is simply a matter of putting a plurality of conventionally known rolling stands in front of each other, the equipment cost is proportional to the number of passes required. Although it cannot be said that the equipment cost is unreasonably large, the equipment cost is quite large when compared to the case where reciprocating rolling is performed in one stand.

Second, since two regular rolling stands are installed side by side, the housing posts of both rolling stands must be placed together between the pairs of upper and lower work rolls that share each bus. , and the space required for attaching both housings to the foundation, it is not possible to bring the two locations where rolling takes place sufficiently close together. This makes it difficult to roll thinner or longer sheets because the time between each pass is long and the temperature drop is correspondingly large.

Thirdly, because the two pairs of work rolls are not close enough, when the material to be rolled becomes thin to a certain extent, even if you try to press the tip of the material to be rolled between the next pair of work rolls, If the material is buckled and pressed sufficiently, it will not be possible to obtain enough force, but the material will become unstable due to jamming, which will cause rolling troubles, and it will not be possible to obtain a sufficient amount of thickness reduction. On the other hand, if the material to be rolled is thick, in actual work, the material often comes out bent upwards in the previous pass, and the distance to the pair of upper and lower work rolls for the next pass is long. The effect of this bending becomes so great that the leading edge of the sheet is stuck in a completely different place from the gap between the upper and lower work rolls in the next pass, which causes a serious threading problem. Although such threading druffles can be solved to some extent by providing appropriate guides to prevent whitening, the design of the guides themselves may also be affected by the distance between the pair of work rolls. It gets complicated.

It is an object of the present invention to rationally solve the problems of the conventional tandem rolling mill described above, to achieve a compact structure with low equipment costs, and to dramatically reduce the distance between pairs of adjacent upper and lower work rolls. We provide a tandem rolling mill that allows for a shorter design, reduces the temperature drop of the material to be rolled, saves energy, and eliminates sheet threading troubles, allowing for a large reduction in thickness. It is to be.

[Means for Solving the Problems and Their Effects] The remarkable effects of the present invention are that the functions required for each rolling pass are achieved without any deterioration of the functions of conventional rolling mills;
This is achieved by incorporating multiple pairs of upper and lower work rolls that realize tandem rolling into an integral housing, or left and right respective integral housings. The bearing has a plurality of pairs of lower work rolls with boxes on each of the left and right sides, and each time the material to be rolled passes between each pair of upper and lower work rolls, When the thickness is reduced, the rolling load applied from the material to be rolled in the direction of widening the gap between each pair of upper and lower work rolls is applied directly to the left and right bearings of the work rolls through the box or through the reinforcing rolls to the left and right of the reinforcing rolls. The bearing is supported through the box by the upper and lower parts of the housing, and the upper and lower parts of the housing are mechanically coupled by a housing post extending in the vertical direction, and the rolling load is ultimately applied to the tensile force of the housing post. In a tandem rolling mill that is supported by stress, the rolling load generated between a plurality of pairs of upper and lower work rolls is supported by an integral housing as a whole or by each integral housing on each of the left and right sides, and A housing post is arranged between any two pairs of adjacent upper and lower work rolls, and on both left and right sides of the material to be rolled, for mechanically connecting the upper and lower parts of the housing. tandem rolling mill" and its embodiments as well as its design application to the case of specific conditions.

That is, as shown in the three-dimensional view of FIG. 1 and the side view of FIG. Because it is built into the housing 3.3', there is only one roll on each side of the housing post 5,
Or you only need 5'. For this reason, the housing posts of each stand are not placed between two adjacent pairs of upper and lower work rolls as in the past, and there is also a structural space required to attach the stand to the foundation bolt. is also unnecessary.

Furthermore, since the housings of the plurality of tandem rolling mills in the conventional tandem rolling mill are mechanically connected, the rigidity is large. Since it is only necessary to support the load with tensile stress, it is much smaller than the housing posts 4.4' and 6.6' located on the outermost side of the housing, which must be designed with bending deformation as the main focus. A cross-sectional area may be sufficient.

In other words, when the tip of the material to be rolled is being rolled by only the set 1.1' of the upper and lower work rolls while it is passing through, the material is being rolled between another set 2.2' of the upper and lower work rolls. Since the load is at the opening, the part of the housing that is integrally connected 6
．． 6' and the upper and lower housing parts of the upper and lower work roll set 2.2' contribute to supporting the rolling load, and the bending deformation of the housing post 5.5' is caused by the housing post 4.4. ′ is smaller than the bending deformation of ′.

Also, as the material to be rolled progresses, the set of upper and lower work rolls 2.2
Even when rolling is being performed, the front and rear of the housing post 5.5' are deformed or become almost symmetrical, so the bending of the housing post 5.5' is small. In this way, the housing post 5.5' can be designed mainly for tensile stress to resist the rolling load, which is different from the conventional housing post of a rolling mill, which had to be designed mainly for bending or being small. By increasing the ratio, the cross-sectional area can be reduced, and two adjacent
The distance between the pair of lower work rolls can be shortened.

As described above, the operation of the present invention is essentially different from that of a conventional tandem rolling mill in which adjacent stands are brought close to each other to such an extent that the outer surfaces of their housing posts touch each other; By mechanically coupling the housings involved in the rolling bath, the rigidity of the rolling mill as a whole is increased due to the physically coupled housings, thus making it possible to design an overall compact rolling mill. Furthermore, this makes it possible to minimize the distance between the plurality of locations where the material to be rolled is rolled.

In rolling metal sheets, the rolling load generated in the gap between the upper and lower work rolls is transmitted from the left and right bearings of the upper and lower work rolls or the reinforcing rolls from each box to each location on the left and right sides of the housing. supported separately on the sides.

Therefore, mechanically connecting the left and right housings has no practical significance, and is simply a design or manufacturing problem. Therefore, assuming that the main structure of the rolling mill is bilaterally symmetrical, only the side visible in the side view of FIG. 2 will be described below. However, although it makes sense to connect the left and right housings with a relatively weak member for the purpose of preventing vibrations, this is not important to the present invention.

Next, a
The function of the housing post 5 will be explained.

This is because the upper and lower parts of the integral housing 3 have a beam structure, and when a rolling load is applied to these parts, the beams have the effect of reducing deflection and increasing rigidity. That is, if the housing post 5 were not provided, the upper and lower parts of the housing 3 would have a very large deflection as beams.
and the thickness of the lower part must be very large.

Further, even if the housing post 5 is eliminated and the housing 3 is made to have sufficient strength to support the rolling load, it is inevitable that some degree of elastic deformation will occur. This is not just a disadvantage of reduced stiffness.

That is, when rolling a metal sheet, there are strict requirements regarding the roughness of the thickness, and in many cases, it is necessary to perform control to compensate for deformation of the rolling mill. For this purpose, conventional rolling mills
An automatic thickness control method is used in which the rolling load is measured and the gap between the upper and lower work rolls is controlled based on the measured value. However, if the housing post 5 is omitted, it is not sufficient to simply adopt such a conventional control method. This occurs because the rolling load generated in the gap between the upper and lower work roll pairs to be controlled is not enough, and the housing is integrally connected to the other lower work roll pair. This is because it also depends on the rolling load. That is, as in the conventional method, it also depends on the rolling load generated between the relevant pair of working rolls.

That is, it is insufficient to manipulate the gap between the upper and lower work roll pairs based only on the rolling load generated between the upper and lower work roll pairs, as in the conventional method. The housing post 5 has the important function of increasing the rigidity of the housing 3, eliminating mutual interference between the buses, and facilitating automatic thickness control, and as in the present invention, This is an essential requirement when a plurality of pairs of upper and lower work rolls are assembled into a single housing.

As will be explained later in the examples, it is possible to use a control method that compensates for the mutual interference of each path in the automatic thickness control described above. However, in order to expect sufficient effects from control, it is necessary to reduce the rigidity as described above,
Furthermore, it is a prerequisite that the degree of mutual interference is small to some extent, and in order to guarantee sufficient thickness accuracy, it is essential to provide the housing post 5. On the other hand, when the housing post 5 is provided, the deformation of the housing 3 can be sufficiently reduced without making the upper and lower parts of the housing 3 particularly large. Depending on the application situation, it is often sufficient to apply thickness control in conventional rolling mills.

In the present invention, "mechanically coupled" means that two parts are continuous so that there is no displacement of the relative positions of the two parts due to elastic deformation, or two parts are welded. Or, if they are semi-permanently connected by mechanical means such as strong bolts, and the connection is severed,
When a rolling load occurs at any location, the two parts may undergo a relatively large displacement compared to when they are connected.

[Example] Fig. 1 shows an example in which the present invention is implemented in a steel roughing mill to perform tantem reciprocating rolling, and Fig. 2 shows a side view thereof. Figure 1 shows housing 3.3'
is shown by a dashed line, and the parts hidden behind the housing that cannot be seen are also shown as being transparent. In addition, the structure of the left and right sides of the rolled material S is almost symmetrical except for the rotational drive of the work roll or the fact that the work roll is driven only from one of the left and right sides, so the work roll 1.1'
, 2.2' and reinforcing roll +1. II', 12, 1
2' bearing is a box 21.22.31.32 and a structure for transmitting the rolling load from these to housing 3.3', a reduction screw 51.52 and a hydraulic jack 61,
δ2 shows only one side, left and right, so that the structure hidden behind the straw can be shown.

The material is a steel slab heated to about 1100°C, and its typical thickness is 200mm. A typical thickness reduction schedule assumes that for each rolling pass in which the material to be rolled passes through the gap between the upper and lower work rolls, the thickness is reduced by approximately 30%.

In this case, the thickness of the rolled material S becomes approximately 1/2 in two rolling passes while passing from the left side to the right side in the figure. Therefore, assuming that the material is fed from the left side of the figure and is sent to the finishing mill located on the right side of the figure after rolling, 20
When a 0 mm thick material is rolled to the right, then rolled to the left, and then rolled again to the right, its thickness becomes approximately 25 mm, and rough rolling is completed. The time required for rolling during this period is approximately 1/2 of that required for reciprocating rolling with one stand, and the temperature decreases by 1/2.
/2.

The rolling mill of this embodiment is designed to withstand a maximum rolling load of 3000 tons in each rolling pass. The structure of the roll diameter for each of the two pairs of upper work rolls 1, 1' and 2.2' is the structure of a four-high rolling mill provided with reinforcing rolls 11, 11' and 12, +2'. It is. The diameter of work rolls 1.1' and 2.2' is φ800 mm, and the reinforcing rolls II, 11', and 12
．． The diameter of the roll 12' is φ1600 mm, and the length of the body is 2000 mm, making it possible to roll a material S having a maximum width of 1800 mm.

In the case of this level of rolling load, the outer housing post 4
．． In order to ensure bending rigidity, the cross-sectional area of No. 6 needs to be about 800 mm2 (dimension in the rolling direction x dimension in the width direction - 800 mm2). However, the cross-sectional area of the central housing post 5 is 500 x 8 because it does not require much bending rigidity.
00 mm2 is enough for 2 sets of work rolls 1
．． The distance between 1' and 2,2' is the diameter of the reinforcing roll +
It comes to about 500mm. The kneading is 1100 mm shorter than the distance when the conventional rolling mills are placed close together, that is, the diameter of the reinforcing roll + 2 x the dimension of the housing post (2 x 800 mm). Moreover, as before, 2
In the method of simply bringing the rolling mills of the stands closer together, in order to fix the two housings to the foundation between the two stands, the mounting of the housing foundation requires a structural space in part 7.8 and in the foundation itself. - Since the strength rolling mill does not need to be attached to the foundation in this part, the difference in distance between the two pairs of lower working rolls is much larger than above.

As described above, it is clear that this rolling mill is superior to two conventional rolling mills in terms of rolling time and prevention of sheet passing accidents at the tip. Furthermore, since it is sufficient to provide a relatively small housing post 5 in the middle, the overall weight is also significantly improved.
It is possible to provide a compact rolling mill.

The type of rolling mill for each rolling bus has been explained as a four-high rolling mill, but if limited to a local area, this rolling mill has the same function as a conventional rolling mill. It is also possible to use a two-high rolling mill that does not have a rolling mill, a six-high rolling mill that has an intermediate roll between the work roll and reinforcing roll, or a structure that slightly deviates the axes of the upper and lower work rolls from parallel. You can also take

FIG. 2 also shows the interaction with a finishing mill 102 when the present invention is applied to a rough rolling mill 101 for rolling thin steel sheets. Although the finishing mill 102 is a conventional 4-stant tandem finishing mill with four rolling stands arranged side by side, only the first rolling stand 102 is shown in the figure.

The rough rolling process is the same as in the embodiments already described. However, in this case, when performing the final rightward rolling to roll the material from 50 mm to 25 mm in thickness, all parts of the material to be rolled have not left the rough rolling mill 101, but the leading end is rolled in the finishing mill 102. To be rolled, that is, rough rolling mill 101
This shows that it is also possible for the finishing rolling mill 102 to perform tandem rolling as a whole.

The rough rolling mill 101 determines whether such a rolling form will be achieved.
It depends on whether the distance between the end rolling mill 102 and the finish rolling mill 102 is designed to be proportional to the length of the material S to be rolled. If the roughing mill performs reciprocating rolling, this rolling mode can only be used when performing roughing or final rightward rolling, and the distance between the roughing and finishing mills should be at least as long as the final rightward rolling. The length of the material to be rolled before the leftward rolling is required. In the case of the present invention, the thickness of the material to be rolled at this point is 100 mm, while in the case of reciprocating rolling with one stand, the corresponding thickness is 50+n+n. Therefore, when the rolling form of this embodiment is adopted, the distance between the roughing mill and the finishing mill can be reduced to approximately 1/2 by using the tandem reciprocating mill of the present invention, compared to using a one-stand reciprocating mill. It is possible to reduce the size to 2, and the entire factory can be made more compact.

Note that the rolling mill 101 shown in FIG. 2 includes a pair of upper and lower work rolls 1. Load detectors 71 and 72 are provided to measure the rolling loads generated in each pair of I' and 2.2'. As is well known, this is used for automatic thickness control in which the gap between the upper and lower work rolls changes due to the occurrence of rolling load, and is corrected according to the detected value of rolling load. It is for the purpose of

That is, by applying the conventional automatic thickness control method, for example, depending on the value of the rolling load measured by the rolling load detector 71, the upper work roll 1. By controlling the gap between the upper and lower work rolls 1.1', the thickness after being rolled by the upper and lower work roll pair 1.1' can be controlled to be approximately equal to the desired thickness. Such control is the same for the other pairs of upper and lower work rolls 2.2'.

In addition, in this rolling mill, two pairs of upper and lower work rolls are assembled into an integrated housing 3, so the gap between the upper and lower rolls in the first pass is not 4 cm in the first pass, but in the second pass. Mutual interference between multiple buses occurs, as the rolling loads of all buses are also involved. Therefore, ideally, for example, when performing automatic thickness control of a rolling bath using the upper and lower work roll pair 1.1',
In addition to the detector 7 of the rolling load generated by the upper and lower work roll pair 1.1', the detection value by the detector 72 of the rolling load generated by the other upper and lower work roll pair 2.2' is also used.
The gap between the upper five work rolls 1.1' may be corrected based on both detected values. Such automatic thickness control also applies to correction of the gap between the pair of upper and lower work rolls 2.2'.

Actually, by providing the housing post 5,
Since mutual interference between a plurality of rolling passes as described above can be sufficiently reduced, thickness control that takes mutual interference into consideration is often unnecessary. However, depending on the design, such as making the housing post 5 as small as possible, it may be necessary to control the gap between a specific pair of upper and lower work rolls according to the detected values of a plurality of rolling loads. In some cases, the thickness characteristics can be improved to a meaningful extent.

[Effects of the Invention] The rolling mill of the present invention described above has a compact structure and is advantageous in terms of equipment, can minimize the temperature drop of the rolled material, and can reduce the amount of thickness reduction of the rolled material. This makes it possible to increase the amount in a short period of time, and the industrial effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the tandem rolling mill, showing an example in which the present invention is implemented in a tandem rolling mill having two pairs of work rolls. FIG. 2 is a side view of the tandem reciprocating rolling mill, showing an example in which the present invention is implemented in a tandem reciprocating rolling mill having two pairs of work rolls.

Claims (1)

[Claims] 1. A plurality of pairs of upper and lower work rolls that are substantially parallel to each other, rotate in opposite directions, and have bearing boxes on each of the left and right sides, and the material to be rolled is The thickness is reduced each time it passes between each pair of upper and lower work rolls, and at that time, the rolling load applied from the material to be rolled in the direction of widening the gap between each pair of upper and lower work rolls is applied directly to the left and right bearing boxes of the work rolls. The upper and lower parts of the housing are supported by the upper and lower parts of the housing through the left and right bearing boxes of the reinforcing roll, and the upper and lower parts of the housing are mechanically coupled by a housing post extending in the vertical direction. In a tandem rolling mill where the rolling load is ultimately supported by the tensile stress of the housing post, the rolling load generated between multiple pairs of upper and lower work rolls can be handled either as a whole or on each of the left and right sides. The upper and lower parts of the housings are supported by each integral housing, and the upper and lower parts of the housings are mechanically connected between any two pairs of adjacent upper and lower work rolls, and on both the left and right sides of the material to be rolled. A tandem rolling mill characterized by the arrangement of housing posts. 2. Provide a rotational drive power source that is independent for each of the plurality of pairs of upper and lower work rolls, and for any pair of upper and lower work rolls, such that the upper and lower sides are common or the upper and lower sides are independent, and 2. The tandem rolling mill according to claim 1, wherein the rotation direction of the drive power source is common to all of the plurality of pairs of work rolls, and can be rotated in the forward direction and rotated in the reverse direction. 3. It has a plurality of pairs of upper and lower work rolls that are substantially parallel to each other, rotate in opposite directions, and have bearing boxes on each of the left and right sides, and the material to be rolled is rolled by each pair of upper and lower work rolls. At that time, the rolling load applied from the material to be rolled in the direction of widening the gap between each pair of upper and lower work rolls is applied directly through the left and right bearing boxes of the work rolls or through the reinforcing rolls. The upper and lower parts of the housing are supported through the left and right bearing boxes of the reinforcing roll, and the upper and lower parts of the housing are mechanically connected by a housing post extending in the vertical direction, so that the final rolling load is In tandem rolling machines, such as those supported by the tensile stress of housing posts, the rolling load generated between multiple pairs of upper and lower work rolls is supported either by the entire housing or by each integral housing on each of the left and right sides. and a device for measuring the rolling load generated between at least two pairs of upper and lower work rolls among the plurality of pairs of upper and lower work rolls, and a device for inputting the measured values of the plurality of rolling loads and based on the an arithmetic and control device that calculates and outputs a command value for a gap between at least one pair of upper and lower work rolls; A tandem rolling mill characterized by having a mechanism for changing the gap between a pair of upper and lower work rolls.