EP4122614A1 - Method for producing a coil made of a metallic strip - Google Patents

Abstract

The invention relates to a method for producing a coil (1) of metal strip, the strip being rolled out of a slab in a rolling train (2) by means of a number of rolling stands (3) and then wound up on a coiler (4) to form the coil (1). will. In order to provide coils of wound metallic strip that meet specific requirements and thus allow the user of the coils to make optimal use of a coil, the invention provides that the slab to be rolled is composed of at least two partial slabs (5a, 5b) which connected to one another before rolling in the rolling train (2), the finished coil (1) having at least two strip sections (6a, 6b) which were manufactured from the at least two partial slabs (5a, 5b).

Description

The invention relates to a method for producing a coil of metal strip, the strip being rolled out of a slab in a rolling train by means of a number of roll stands and then wound up on a coiler to form a coil.

Typically, according to the process mentioned, strip is rolled in a rolling mill and then wound into a coil. The coil is delivered to its place of use and then recycled as intended. This means in particular that products corresponding to the defined specification are manufactured from the band.

However, it can also happen that a buyer of a coil wants to use it for different products or for different purposes. In this case, the use of a homogeneous coil can be disadvantageous.

The invention is based on the object of developing a method of the type mentioned at the outset in such a way that it is possible to provide coils of wound metallic strip that meet specific requirements. The coil should have different strip sections that differ in their properties and thus allow the user of the coil to optimally use a coil. In particular, it should also be possible to produce strip from pre-strips or thin slabs with different steel grades and/or with different thicknesses and widths and to provide them in a coil.

The solution to this problem by the invention is characterized in that the slab to be rolled is composed of at least two partial slabs which are connected to one another before rolling in the rolling train are connected, the finished coil having at least two strip sections that were made from the at least two partial slabs.

With regard to the nomenclature, the following should be noted with regard to the term slab used: This term is to be understood here in general terms. The term "slab" is usually used for the material in front of the roughing stand, after which it is roughing strip. Belts are then spoken of in and after the finishing mill. Strips are made from thin slabs in a CSP plant. In the present case, the material before the finishing train is primarily meant. However, slabs in the actual sense can also be treated according to the invention.

The connection of the at least two partial slabs upstream of the rolling mill is preferably carried out by means of a slab connection device. In this case, it is preferably provided that the at least two partial slabs are connected in the slab connecting device by friction welding, in particular by linear friction welding.

The partial slabs and/or the strip sections rolled from them differ from one another in particular in terms of their material.

The band sections can also differ from one another in terms of their geometry, in particular in terms of their width and/or thickness.

Rolling in the rolling mill is preferably carried out in a continuous process.

According to one embodiment of the invention, the at least two partial slabs can be produced in at least two different casting machines.

It is also possible for at least one of the partial slabs to be temporarily stored before being connected to the other partial slab. The intermediate storage of one partial slab preferably takes place at least temporarily in a furnace. The one partial slab can also be temporarily stored in a coil box, at least temporarily.

At least one of the partial slabs can be supplied as separately manufactured material from another manufacturing facility. It can also be provided that the material supplied is used as a sample, as a model or as material for calibrating the rolling train or parts thereof. This material or any other part can then be taken for samples or samples or as scrap, in particular as planned in the event of changes in production conditions (so-called transition zones) or as a result of production phases that do not go according to plan.

The slab joining device is preferably provided between a tunnel furnace following a caster and the first stand of a finishing train in a cast-rolling plant.

The slab joining device can also be provided between the last stand of a roughing train and the first stand of a finishing train in a hot rolling mill.

Regarding the joining of two slabs, it is from WO 2017/140886 A1 It is known to produce steel strips in a casting-rolling plant in semi-endless rolling or in endless rolling by producing slabs in one or more casting machines, which are connected to one another before the rolling train. To this end, the document mentioned describes a slab connecting device with which two slabs arranged one behind the other can be connected to one another. This is done here by a friction welding process in which the two slabs to be joined oscillate relative to each other and are pressed against each other.

The same applies if, for example, a strip is rolled in a hot rolling mill. Here, too, the strip to be finish-rolled can be assembled from several sub-strips, which are provided from a coil box or directly from the roughing mill.

As already mentioned, if slabs are mentioned here, this also includes pre-strips that are connected to one another in order to be able to roll them out, in particular in a continuously operating rolling process.

The proposed method can be used in conventional hot strip mills or in continuous casting plants (CSP plants).

In particular, friction welding devices are used as the slab joining device, as in the above-mentioned WO 2017/140886 A1 are described. With the slab connecting device in a conventional hot strip mill or a casting and rolling plant, pre-strips or thin slabs can therefore be connected and then rolled together.

The proposed method thus allows the joining of slabs or pre-strips with different properties. Before rolling, the strips are preferably connected to one another by friction welding, then rolled and finally wound into a coil in such a way that there are different strip sections on it, which are characterized by different properties.

The strip wound into a coil has at least two, preferably several sections, which in particular consist of different materials or have different geometric dimensions. The slabs or pre-strips that are joined together can come from different sources and in particular from external production. The point of separation before coiling is defined at a desired location that is independent of the point at which the slabs or pre-strips were connected to one another.

It is also possible, for example, to produce two coils (in the example with 1.5 times the weight) from three partial slabs.

Significant advantages are achieved with the proposed method:
According to a customer's request, an individual coil can be provided flexibly, which has any number of sections of any length, which in particular relates to different thicknesses, widths and materials.

Any segments from a discontinuous part of the process (furnace area in the CSP process; roughing line in the HSM process) can be removed before the slabs or pre-strips are welded, which can be done with shears (e.g. before the CSP furnace or in front of the finishing train of an HSM plant, but at the latest with the shears of the friction welding machine); this applies in particular to transition areas, rejects and samples.

Corresponding segments can also be inserted, in particular CSP material that has been in the furnace for a long time, or foreign material that has been produced externally on a separate rolling stand and then introduced, as well as sample material that has been rolled and is then to be examined.

In this way, a material that meets the requirements or specifications can be wound into a coil.

This means that the supplied coil can also be better coordinated with subsequent processes that are planned for the customer of the coil (e.g. it is not possible to separate at the weld seam before winding because it would have to be reconnected there before cold rolling, but at another point, which makes more sense for the customer of the coil).

Fig. 1

schematisch eine Gießwalzanlage zur Herstellung eines metallischen Bandes, wobei hinter zweier Tunnelöfen eine Brammenverbindungsvorrichtung angeordnet ist sowie hinter derselben eine Walzstraße mit sich anschließendem Haspel, und

Fig. 2

schematisch ein Coil metallischen Bandes, welches aus zwei unterschiedlichen Bandabschnitten besteht.

In the drawing an embodiment of the invention is shown. Show it:

1

schematically shows a casting and rolling plant for the production of a metal strip, with a slab connecting device being arranged behind two tunnel furnaces and a rolling train with subsequent coiler being arranged behind the same, and

2

schematically a coil of metallic strip, which consists of two different strip sections.

In figure 1 a system is shown schematically with which a steel strip can be produced.

First, in two casting machines 8 and 9, a slab 5a or 5b is produced, which has a certain length. The slabs each enter a tunnel furnace 10 in which they are kept at a defined temperature. Downstream in the rolling direction R is a rolling train 2 which has a number of rolling stands 3 . Between the end of the tunnel furnace 10 and the rolling train 2 is a slab-joining device 7 (a suitable slab-joining device is described in the above WO 2017/140886 A1 described). This serves the slabs 5a, 5b from the To connect tunnel furnaces 10 to each other and to guide them into the rolling train 2, so that a continuous rolling process can take place in the rolling train, which is generally advantageous with regard to the process stability and the quality of the strip to be produced. Accordingly, the slab to be rolled is assembled from two partial slabs 5a and 5b and fed to the rolling train 2 .

Behind the rolling train 2 there is a coiler 4 with a coiler mandrel 11 (see Fig. figure 2 ), on which the rolled strip is wound into a coil 1.

It is essential that the properties of the two partial slabs 5a, 5b differ from one another and/or that the strip rolled from the two partial slabs 5a, 5b has different properties. The coil 1 is wound in such a way that it consequently has at least two strip sections 6a and 6b, which differ from one another in terms of their properties.

The two band sections 6a, 6b are in figure 2 marked with different hatching.

Accordingly, the finished coil 1 has different strip sections that differ, for example, in their metallurgical properties or steel grades or also in their geometry (in terms of width and/or thickness).

This means that the coil can contain equivalent materials, but also, for example, a strip material to be processed and a sample of a different material.

The buyer of the coil 1 thus has the possibility of supplying a single coil to different uses, in which the respective strip sections are recycled or used differently.

Reference list:

1

coil

2

rolling mill

3

mill stand

4

reel

5a

partial slab

5b

partial slab

6a

first band section

6b

second band section

7

slab connecting device

8th

casting machine

9

casting machine

10

tunnel kiln

11

mandrel

R

rolling direction

Claims (14)

Method for producing a coil (1) of metallic strip, the strip being rolled out of a slab in a rolling train (2) by means of a number of rolling stands (3) and then wound up on a coiler (4) to form the coil (1),
characterized,
that the slab to be rolled is composed of at least two partial slabs (5a, 5b) which are connected to one another before rolling in the rolling train (2), the finished coil (1) having at least two strip sections (6a, 6b) which were made from the at least two partial slabs (5a, 5b). Method according to Claim 1, characterized in that the at least two partial slabs (5a, 5b) are connected upstream of the rolling train (2) by means of a slab connecting device (7). Method according to Claim 2, characterized in that the at least two partial slabs (5a, 5b) are connected in the slab connecting device (7) by friction welding, in particular by linear friction welding. Method according to one of Claims 1 to 3, characterized in that the partial slabs (5a, 5b) and/or the strip sections (6a, 6b) rolled from them differ from one another in terms of their material. Method according to one of Claims 1 to 4, characterized in that the strip sections (6a, 6b) differ from one another in terms of their geometry, in particular in terms of their width and/or their thickness. Method according to one of Claims 1 to 5, characterized in that the rolling in the rolling train (2) takes place in a continuous process. Method according to one of Claims 1 to 6, characterized in that the at least two partial slabs (5a, 5b) are produced in at least two different casting machines (8, 9). Method according to one of Claims 1 to 6, characterized in that at least one of the partial slabs (5a, 5b) is temporarily stored before it is connected to the other partial slab (5a, 5b). Method according to Claim 8, characterized in that the intermediate storage of one partial slab (5a, 5b) takes place at least temporarily in a furnace. Method according to Claim 8, characterized in that the intermediate storage of one partial slab (5a, 5b) takes place at least temporarily in a coil box. Method according to one of Claims 1 to 10, characterized in that at least one of the partial slabs (5a, 5b) is supplied as separately manufactured material from another manufacturing facility. Method according to Claim 11, characterized in that the material supplied is used as a sample, as a model or as material for calibrating the rolling train (2) or parts thereof. A method according to any one of claims 1 to 12, characterized in that the slab connecting device (7) is provided between a tunnel furnace (10) following a caster (8) and the first roll stand of a finishing train (2) in a cast-rolling plant. Method according to one of Claims 1 to 13, characterized in that the slab connecting device (7) is provided between the last rolling stand of a roughing train and the first rolling stand of a finishing train in a hot rolling mill.

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