Title of Invention	A PROCESS OF PRODUCING HOT-ROLLED STEEL STRIP
Abstract	The present invention relates to a process of producing hot-rolled steel strip from continuously cast precursor material in at least two deformation stages, each having one or more roll stands, wherein the precursor material is rolled out continuously in the fIrst deformation stage, at the speed at which the precursor material exists from the continuous casting plant, to form an intermediate strip which, prior to the second deformation, is coiled at the exit speed from the fIrst deformation stage without subdivision to form an intermediate coil and is then uncoiled in order to supply the intermediate strip to the more or less continuous fmish-rolling, after which this intermediate strip is sub-divided in accordance with the respectively desired coil weights and is coiled as fmished strip, characterized in that at least 40 tons of a casting sequence of the continuous casting plant is cast to form precursor strip and rolled out in the fIrst deformation stage to form an intermediate strip, the metallurgical characteristics of which are altered by changing the temperature control prior to coiling the intermediate coil and/or prior to the second deformation stage and by flexible speed control within an intermediate coil length.

Title of Invention

A PROCESS OF PRODUCING HOT-ROLLED STEEL STRIP

Abstract

The present invention relates to a process of producing hot-rolled steel strip from continuously cast precursor material in at least two deformation stages, each having one or more roll stands, wherein the precursor material is rolled out continuously in the fIrst deformation stage, at the speed at which the precursor material exists from the continuous casting plant, to form an intermediate strip which, prior to the second deformation, is coiled at the exit speed from the fIrst deformation stage without subdivision to form an intermediate coil and is then uncoiled in order to supply the intermediate strip to the more or less continuous fmish-rolling, after which this intermediate strip is sub-divided in accordance with the respectively desired coil weights and is coiled as fmished strip, characterized in that at least 40 tons of a casting sequence of the continuous casting plant is cast to form precursor strip and rolled out in the fIrst deformation stage to form an intermediate strip, the metallurgical characteristics of which are altered by changing the temperature control prior to coiling the intermediate coil and/or prior to the second deformation stage and by flexible speed control within an intermediate coil length.

Full Text	The invention relates to a process of produciwcj hot rolled steel strip from a continuously cast pre-strip in at least two deformation steps, each comprising one or more roll stands, whereby, in the first deformation step, rolling is started at the rate of delivery of the pre-strip from the continuous casting plant, and the thus produced intermediate strip, prior to the second deformation step, is wound up at the rate of delivery from the first deformation step to form a coil and, once the coil mass is achieved, is unwound and directed at the first-pass rate to the second deformation step for completing the rolling operation, and is then wound up in the desired final coil size. A typical process of this kind is described, for example, in German Patent 3 8 40 812 C2, and has become known in the relevant literature by the term ISP process. The essential feature of this process is the two-step rolling process, in which the first deformation step takes place immediately following on the casting machine, at the casting rate, and in which the second deformation step is carried out at a distinctly higher rolling speed. These two steps in the rolling process are coupled by an intermediate winding system in the form of a reel furnace, in which the continuously cast slab, after rolling out, is wound into a coil, the mass of which corresponds to the desired final coil mass. The subdividing of the, initially, endlessly produced continuous casting is therefore carried out downstream of the first deformation step when that coil mass which is equal to the mass of the final coil after rolling in the second deformation step is achieved in the reel furnace. When rolling hot strip according to this process, the threading-in of the strip head into the reel constitutes a limitation of the rolling speed, because, at very high speeds, there is a danger that the strip head will move upward on to the run-out roller table. Once the strip head is captured in the reel, it would be possible to increase the rolling speed virtually as desired within the framework of the capacity of the plant and the technological requirements. In order to overcome the above-described limitation of the rolling speed, processes for continuous rolling have been developed, and these are based on the principle of joining the pre-strips prior to their entry into the finishing train. It is, for example, proposed that a plurality of pre-strips be welded together at their end faces, thereby reducing the threading-in operations and permitting a virtually continuous rolling operation. Yet, welding together the pre-strips involves complicated equipment and also limits the possible rolling speed. In the process on which the invention is based, pre-strips are. as already stated above, produced in a continuous casting process and, are wound up to form coils, the mass of which . corresponds to the mass of the final strip coil. To this end, once the coil mass has been reached in the intermediate winding station, the pre-strip is cut off and is thus disconnected from the casting plant, with the result that it is possible for an unwinding of the strip into the finishing train to take place at a relatively high rate. The rolling speeds are, however, limited, owing to the above-described danger during threading-in of the strip head into the reel, with the result that considerable problems arise precisely when rolling thin hot strips of the order of less than 1.5 mm. Conventional plants are thus virtually incapable of producing thin hot strip in large quantities. On the basis of the discussed difficulties and drawbacks associated with the prior art, it is the object of the present invention to provide a process for the production of hot-rolled steel strip, whereby it is possible to roll even very thin strips at relatively high final rolling speeds, in a reliable manner. Accordingly, the present invention provides a process of producing hot-rolled steel strip from continuously cast precursor material in at least two deformation stages, each having one or more roll stands, wherein the precursor material is rolled out continuously in the first deformation stage, at the speed at which the precursor material exists from the continuous casting plant, to form an intermediate strip which, prior to the second deformation, is coiled at the exit speed from the first deformation stage without subdivision to form an intermediate coil and is then uncoiled in order to supply the intermediate sfrip to the more or less continuous finish-rolling, after which this intermediate strip is sub-divided in accordance with the respectively desired coil weights and is coiled as finished strip, characterized in that at least 40 tons of a casting sequence of the continuous casting plant is cast to form precursor strip and rolled out in the first deformation stage to form an intermediate sfrip, the metallurgical characteristics of which are altered by changing the temperature confrol prior to coiling the intermediate coil and/or prior to the second deformation stage and by flexible speed confrol within an intermediate coil length. According to the invention, in order to meet this object, it is proposed that, in the first deformation step, at least 40 tons of a casting sequence from the continuous casting plant be rolled continuously to form an intermediate sfrip and, without being subdivided, be wound up into an intermediate coil, and that the intermediate sfrip of this intermediate coil, after a virtually continuous finishing rolling operation, be subdivided only downstream of the second deformation step, according to the coil masses desired in each case, and be wound up as finished strip. Starting material for finishing work in a finishing train is produced in a continuous rolling process in a typical casting plant comprising a downstream pre-deformation unit. Contrary to the usual operating method, whereby this starting material is cut into sections which correspond to the subsequent coil masses, the starting material, in view of the intended continuous rolling, is not cut off downstream of the deformation unit, but is rather wound up, in unseparated form, to form an intermediate coil which comprises a plurality of finished coils. From this intermediate coil, a plurality of coil lengths are then processed to completion in a continuous rolling process in the finishing train. The size of the intermediate coil is determined only by the mechanical layout of the winding unit and by the rolling time during which it is possible for the finishing train to be operated without necessitating a change of rollers. With appropriate winding devices, it is quite possible for entire casting sequences of a continuous casting plant to be rolled endlessly, but, at any rate, greater tonnages than those permitted in plants according to the state of the art. The process steps according to the invention distinctly increase the buffer capacity of the intermediate winding I system. At a winding capacity of about 100 tons, the buffer capacity would, for example, increase to 60 minutes per intermediate coil. As a result of the higher final rolling speeds which are possible in such a process, it is possible to produce endless hot strip with thicknesses of any difficulties. The output of the plant is improved, since the typical rough-rolled end, which must be removed prior to any further processing, is formed only at the beginning of the first and the end of the last coil downstream of the finishing train. In addition, the quality of the rolled stock is improved, since the non-steady state of the first-pass thrust arises only once in the case of the first coil. It is possible for the intermediate strip to be wound up to form an intermediate coil with or without a mandril. In addition, according to a further feature of the invention, it is possible to alter the metallurgical properties within an intermediate coil length by changing the temperature control prior to winding the intermediate coil and/or prior to the second deformation step, and by a flexible speed control. In a further embodiment of the invention, it is provided that the geometric properties of the finished coils produced from an intermediate coil be altered by an appropriate adjustment of the rolling parameters during the deformation of the intermediate strip within the second deformation step. In an advantageous manner, it should be ensured that at least the edges of the intermediate strip are prevented from cooling down during the winding-up of the pre-strip to form the intermediate coil. To summarize, the advantages of the present process include that endless rolling is possible without welding the pre-strip, that the pre-strip properties, with regard to temperature and geometry, are uniform in this endless rolling operation, that the output of the plant is increased as a result of the relatively high possible rolling speeds which are no longer limited by the threading-in operation into the reel, and by providing a large buffer capacity between the casting operation and the finishing train. It is possible for the process to be used within single or dual lane plants, while the winding principle in respect of the pre-strip may take place both mandril-bound in winding furnaces and in so-called coil boxes. WE CLAIM: 1. A process of producing hot-rolled steel strip from continuously cast precursor material in at least two deformation stages, each having one or more roll stands, wherein the precursor material is rolled out continuously in the first deformation stage, at the speed at which the precursor material exists from the continuous casting plant, to form an intermediate strip which, prior to the second deformation, is coiled at the exit speed from the first deformation stage without subdivision to form an intermediate coil and is then uncoiled in order to supply the intermediate strip to the more or less continuous finish-rolling, after which this intermediate strip is sub¬divided in accordance with the respectively desired coil weights and is coiled as finished strip, characterized in that at least 40 tons of a casting sequence of the continuous casting plant is cast to form precursor strip and rolled out in the first deformation stage to form an intermediate strip, the metallurgical characteristics of which are altered by changing the temperature control prior to coiling the intermediate coil and/or prior to the second deformation stage and by flexible speed control within an intermediate coil length. 2. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claim 1, wherein the geometrical characteristics of the finished coils produced from an intermediate coil are altered by suitable adjustment of the rolling parameters during the deformation of the intermediate strip within the second deformation stage. 3. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claims 1 and 2, wherein the coiling of the intermediate strip to form an intermediate coil takes place on a mandrel. 4. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claims 1 and 2, wherein the coiling of the intermediate strip to form an intermediate coil is carried out without a mandrel. 5. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claims 1 to 4, wherein during the coiling of the precursor strip to form the intermediate coil, at least the edges of the intermediate strip are protected against cooling. 6. A process of producing hot-rolled steel strip, substantially as herein described.

Full Text

The invention relates to a process of produciwcj hot
rolled steel strip from a continuously cast pre-strip in at least two deformation steps, each comprising one or more roll stands, whereby, in the first deformation step, rolling is started at the rate of delivery of the pre-strip from the continuous casting plant, and the thus produced intermediate strip, prior to the second deformation step, is wound up at the rate of delivery from the first deformation step to form a coil and, once the coil mass is achieved, is unwound and directed at the first-pass rate to the second deformation step for completing the rolling operation, and is then wound up in the desired final coil size.
A typical process of this kind is described, for example, in German Patent 3 8 40 812 C2, and has become known in the relevant literature by the term ISP process. The essential feature of this process is the two-step rolling process, in which the first deformation step takes place immediately following on the casting machine, at the casting rate, and in which the second deformation step is carried out at a distinctly higher rolling speed. These two steps in the rolling process are coupled by an intermediate winding system in the form of a reel furnace, in which the continuously cast slab, after rolling out, is wound into a coil, the mass of

which corresponds to the desired final coil mass. The subdividing of the, initially, endlessly produced continuous casting is therefore carried out downstream of the first deformation step when that coil mass which is equal to the mass of the final coil after rolling in the second deformation step is achieved in the reel furnace.
When rolling hot strip according to this process, the threading-in of the strip head into the reel constitutes a limitation of the rolling speed, because, at very high speeds, there is a danger that the strip head will move upward on to the run-out roller table. Once the strip head is captured in the reel, it would be possible to increase the rolling speed virtually as desired within the framework of the capacity of the plant and the technological requirements.
In order to overcome the above-described limitation of the rolling speed, processes for continuous rolling have been developed, and these are based on the principle of joining the pre-strips prior to their entry into the finishing train. It is, for example, proposed that a plurality of pre-strips be welded together at their end faces, thereby reducing the threading-in operations and permitting a virtually continuous rolling operation. Yet, welding together the pre-strips involves complicated equipment and also limits the possible rolling speed.
In the process on which the invention is based, pre-strips are.

as already stated above, produced in a continuous casting process and, are wound up to form coils, the mass of which . corresponds to the mass of the final strip coil. To this end, once the coil mass has been reached in the intermediate winding station, the pre-strip is cut off and is thus disconnected from the casting plant, with the result that it is possible for an unwinding of the strip into the finishing train to take place at a relatively high rate. The rolling speeds are, however, limited, owing to the above-described danger during threading-in of the strip head into the reel, with the result that considerable problems arise precisely when rolling thin hot strips of the order of less than 1.5 mm. Conventional plants are thus virtually incapable of producing thin hot strip in large quantities.
On the basis of the discussed difficulties and drawbacks associated with the prior art, it is the object of the present invention to provide a process for the production of hot-rolled steel strip, whereby it is possible to roll even very thin strips at relatively high final rolling speeds, in a reliable manner.

Accordingly, the present invention provides a process of producing hot-rolled steel strip from continuously cast precursor material in at least two deformation stages, each having one or more roll stands, wherein the precursor material is rolled out continuously in the first deformation stage, at the speed at which the precursor material exists from the continuous casting plant, to form an intermediate strip which, prior to the second deformation, is coiled at the exit speed from the first deformation stage without subdivision to form an intermediate coil and is then uncoiled in order to supply the intermediate sfrip to the more or less continuous finish-rolling, after which this intermediate strip is sub-divided in accordance with the respectively desired coil weights and is coiled as finished strip, characterized in that at least 40 tons of a casting sequence of the continuous casting plant is cast to form precursor strip and rolled out in the first deformation stage to form an intermediate sfrip, the metallurgical characteristics of which are altered by changing the temperature confrol prior to coiling the intermediate coil and/or prior to the second deformation stage and by flexible speed confrol within an intermediate coil length.
According to the invention, in order to meet this object, it is proposed that, in the first deformation step, at least 40 tons of a casting sequence from the continuous casting plant be rolled continuously to form an intermediate sfrip and, without being subdivided, be wound up into an intermediate coil, and that the intermediate sfrip of this intermediate coil, after

a virtually continuous finishing rolling operation, be subdivided only downstream of the second deformation step, according to the coil masses desired in each case, and be wound up as finished strip.
Starting material for finishing work in a finishing train is produced in a continuous rolling process in a typical casting plant comprising a downstream pre-deformation unit. Contrary to the usual operating method, whereby this starting material is cut into sections which correspond to the subsequent coil masses, the starting material, in view of the intended continuous rolling, is not cut off downstream of the deformation unit, but is rather wound up, in unseparated form, to form an intermediate coil which comprises a plurality of finished coils. From this intermediate coil, a plurality of coil lengths are then processed to completion in a continuous rolling process in the finishing train. The size of the intermediate coil is determined only by the mechanical layout of the winding unit and by the rolling time during which it is possible for the finishing train to be operated without necessitating a change of rollers. With appropriate winding devices, it is quite possible for entire casting sequences of a continuous casting plant to be rolled endlessly, but, at any rate, greater tonnages than those permitted in plants according to the state of the art.
The process steps according to the invention distinctly increase the buffer capacity of the intermediate winding

I system. At a winding capacity of about 100 tons, the buffer
capacity would, for example, increase to 60 minutes per
intermediate coil. As a result of the higher final rolling
speeds which are possible in such a process, it is possible to
produce endless hot strip with thicknesses of any difficulties. The output of the plant is improved, since
the typical rough-rolled end, which must be removed prior to
any further processing, is formed only at the beginning of the
first and the end of the last coil downstream of the finishing
train. In addition, the quality of the rolled stock is
improved, since the non-steady state of the first-pass thrust
arises only once in the case of the first coil.
It is possible for the intermediate strip to be wound up to form an intermediate coil with or without a mandril. In addition, according to a further feature of the invention, it is possible to alter the metallurgical properties within an intermediate coil length by changing the temperature control prior to winding the intermediate coil and/or prior to the second deformation step, and by a flexible speed control.
In a further embodiment of the invention, it is provided that the geometric properties of the finished coils produced from an intermediate coil be altered by an appropriate adjustment of the rolling parameters during the deformation of the intermediate strip within the second deformation step.
In an advantageous manner, it should be ensured that at least

the edges of the intermediate strip are prevented from cooling down during the winding-up of the pre-strip to form the intermediate coil.
To summarize, the advantages of the present process include that endless rolling is possible without welding the pre-strip, that the pre-strip properties, with regard to temperature and geometry, are uniform in this endless rolling operation, that the output of the plant is increased as a result of the relatively high possible rolling speeds which are no longer limited by the threading-in operation into the reel, and by providing a large buffer capacity between the casting operation and the finishing train.
It is possible for the process to be used within single or dual lane plants, while the winding principle in respect of the pre-strip may take place both mandril-bound in winding furnaces and in so-called coil boxes.

WE CLAIM:
1. A process of producing hot-rolled steel strip from continuously cast precursor material in at least two deformation stages, each having one or more roll stands, wherein the precursor material is rolled out continuously in the first deformation stage, at the speed at which the precursor material exists from the continuous casting plant, to form an intermediate strip which, prior to the second deformation, is coiled at the exit speed from the first deformation stage without subdivision to form an intermediate coil and is then uncoiled in order to supply the intermediate strip to the more or less continuous finish-rolling, after which this intermediate strip is sub¬divided in accordance with the respectively desired coil weights and is coiled as finished strip, characterized in that at least 40 tons of a casting sequence of the continuous casting plant is cast to form precursor strip and rolled out in the first deformation stage to form an intermediate strip, the metallurgical characteristics of which are altered by changing the temperature control prior to coiling the intermediate coil and/or prior to the second deformation stage and by flexible speed control within an intermediate coil length.
2. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claim 1, wherein the geometrical characteristics of the finished coils produced from an intermediate coil are altered by suitable adjustment of the rolling parameters during the deformation of the intermediate strip within the second deformation stage.
3. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claims 1 and 2, wherein the coiling of the intermediate strip to form an intermediate coil takes place on a mandrel.

4. The process of producing hot-rolled steel strip from continuously cast precursor
strip according to claims 1 and 2, wherein the coiling of the intermediate strip to form
an intermediate coil is carried out without a mandrel.
5. The process of producing hot-rolled steel strip from continuously cast precursor strip according to claims 1 to 4, wherein during the coiling of the precursor strip to form the intermediate coil, at least the edges of the intermediate strip are protected against cooling.
6. A process of producing hot-rolled steel strip, substantially as herein described.

Documents:

0694-mas-97 abstract-duplicate.pdf

0694-mas-97 abstract.pdf

0694-mas-97 assignment.pdf

0694-mas-97 claims-duplicate.pdf

0694-mas-97 claims.pdf

0694-mas-97 correspondence-others.pdf

0694-mas-97 correspondence-po.pdf

0694-mas-97 description (complete)-duplicate.pdf

0694-mas-97 description (complete).pdf

0694-mas-97 form-13.pdf

0694-mas-97 form-2.pdf

0694-mas-97 form-26.pdf

0694-mas-97 form-4.pdf

0694-mas-97 form-6.pdf

0694-mas-97 others.pdf

0694-mas-97 petition.pdf

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Patent Number

196294

Indian Patent Application Number

694/MAS/1997

PG Journal Number

20/2006

Publication Date

19-May-2006

Grant Date

18-Nov-2005

Date of Filing

02-Apr-1997

Name of Patentee

M/S. VODAFONE HOLDING GMBH

Applicant Address

MANNESMANNUFER 2, 40213 DUSSELDORF,

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. ING. JOACHIM SCHONBECK	SALIERSTRASSE 22, D-40545 DUSSELDORF
2	ING. HAN HOPPMANN	NOSENBERGER STRASSE 86, D-40472 DUSSELDORF
3	ING. HERBERT QUAMBUSCH	AGNES-MIEGEL-STRASSE 2, D-40882 RATINGEN

PCT International Classification Number

B21B 1/46

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	196 17 856.8	1996-04-23	Germany