RU2518821C2 - Putting into operation of finishing mill stands at combined foundry-rolling plant - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy and may be used for strip hot rolling at combination mill. Combined foundry-rolling plant comprises foundry plant for liquid steel casting, bloomer stands, rough strip cutting shears arranged downstream of bloomer stands finishing stands and strip reel.

EFFECT: accelerated pitting into operation.

13 cl, 2 dwg

Description

The present invention relates to a method for commissioning a finishing group of stands of a rolling mill in a combined casting and rolling plant and a combined casting and rolling plant for implementing this method.

Technical field

On the one hand, the invention relates to a method for commissioning a finishing group of stands of a rolling mill in a combined foundry-rolling installation, which includes the following steps of the method:

- continuous casting of liquid metal, preferably steel, to obtain a casting product in a foundry;

- crimping the casting product to obtain a draft strip in the crimping group of stands.

On the other hand, the invention relates to a combined foundry-rolling installation for implementing this method, including

- a casting plant for casting liquid steel to obtain a casting product, preferably a thin slab;

- a crimping group of stands for crimping the casting product to produce a draft strip, wherein the crimping group of stands is installed after the casting plant;

- the first scissors for cutting the draft strip to obtain a segment of the draft strip, and the first scissors are installed after the crimping group of stands;

- a finishing group of stands for finishing rolling of a section of a rough strip to obtain a segment of a finished strip, while the finishing group of stands is installed after the first scissors; and

- a winder for winding a segment of the finished strip, while the winder is installed after the finishing group of stands.

State of the art

When commissioning a combined foundry-rolling installation, which is an installation (for example, a CSP (Compact Strip Production - compact strip production), ISP (Inline Strip Production - continuous strip production) or ESP (Endless Strip Production - endless strip production) ), in which at least one foundry unit is connected (more precisely, connected) with at least one rolling unit, the casting unit is first commissioned, then the crimping group of stands, usually including several rolling stands, and then only then the finishing group of stands. When commissioning the finishing group of stands according to the prior art, liquid metal (usually molten steel) in a casting plant (usually a continuous casting machine or a twin roll casting machine) is continuously cast to obtain a fully hardened casting product (for example, in the form of a slab or thin slab), before than the cast product, uncut and in the temperature state of the continuous casting process, is subjected to pressure treatment in a crimping group of stands (for example, multi-stand “High Reduction Mill” - a rolling mill with sokoy reduction ratio) to obtain a blister band. Then, the uncut cut strip continuously leaving the crimping group of stands is fed into the finishing group of the stands and there is subjected to pressure treatment to obtain a finished strip, while the crimping group of the stands is connected to the finishing group of the stands by rolling. This connection of two groups of rolling stands - the so-called combination of rolling - when commissioning a combined foundry-rolling installation requires high-precision and lengthy preliminary design work, including many simulations of rolling processes (the so-called “Ghost rolling sessions”, which are performed without rental), so that commissioning lasts for a long time, and at the same time there are high costs.

SUMMARY OF THE INVENTION

The objective of the invention is to overcome the disadvantages of the prior art and to provide a method for commissioning a finishing group of stands in a combined casting and rolling plant and a combined casting and rolling plant for implementing this method, with which the fastest and most quick simulations of rolling processes can be completed groups of stands of a combined foundry-rolling installation.

This problem is solved using the method according to claim 1, which is different

- cutting the draft strip to obtain a segment of the draft strip using the first scissors, before the head of the draft strip is included in the finishing group of stands;

- finishing rolling a section of the roughing strip in the finishing group of stands with obtaining a segment of the finished strip; and

- winding a section of the finished strip in a coiler.

Cutting the uncut roughing strip to obtain a section of the roughing strip, whereby the cut-off part of the roughing strip is called the cutting of the roughing strip, by means of the first scissors, before the head part of the roughing strip enters the finishing group of the stands (i.e., into the first rolling mill in contact with it stand of the finishing group of stands), leads to the detachment of the crimping group of stands from the finishing. In this case, the first scissors are located in the direction of transportation of the draft strip between the crimping group of stands and the finishing group of stands. Due to this, the commissioning of the finishing group of stands can also be quickly and easily performed by commissioning personnel who do not have or possess only a little specialized knowledge in the field of combined foundry-rolling plants. By finishing rolling a section of the draft strip, a section of the finished strip is produced, which is usually wound up after cooling in a coiler to produce a riot. When winding, on the one hand, it is possible to maintain a compact total length of the combined foundry-rolling plant (i.e., significantly more compact than with the horizontal exit area of the finished strip or, accordingly, a segment of the finished strip), and on the other hand, made in this way riot may already be on sale.

To detach the crimping group of stands from the finishing stand, it is preferable if the length of the roughing strip is accelerated on the conveyor in the direction of the finishing stand group. Preferably, the tail portion of the draft strip at the entrance to the finishing group of stands is at a distance of at least 1-5 m from the uncut head portion of the draft strip.

For the stability of the finish rolling process, the course of the belt and the winding process, it is preferable if the length of the section of the finished strip is greater, preferably at least 1.1 times greater than the length of the path of the tape between the finishing group of the stand and the coiler. By the path length of the tape is meant the unwound length that the finished strip or, respectively, the segment of the finished strip, i.e. the finished rolling section of the draft strip, between the finishing group of the stands and the coiler. In this case, the head part of the finished strip section enters the coiler even before the tail section of the draft strip section is rolled in the finishing group of stands. Thanks to this, you can simply maintain the belt tension necessary for stability.

For winding a section of the finished strip, it is preferable if the section of the finished strip is cooled in the cooling device to a winding temperature.

To ensure the desired structure in the wound section of the finished strip, it is preferable if the section of the rough strip is heated in the furnace to a rolling temperature before finishing rolling, preferably by induction. Thanks to induction heating, the heating of a section of the roughing strip can quickly adapt to various transport speeds.

In order to prevent defects (roll-in) of scale in a section of the finished strip, it is preferable that the section of the draft strip after heating be subjected to descaling in the descaling apparatus. Alternatively, it would also be possible to subject a portion of the roughing strip to descaling prior to heating and to perform heating in an atmosphere of an inert protective gas.

For the application of coilers on the market, it is preferable if the specific gravity per unit width of the draft strip is more than 3.5 t / m, preferably more than 4.5 t / m. With a draft strip width of 1.4 m, a weight of 5 tons is thus obtained, preferably approx. 6.5 t, for a section of the draft strip and for riot.

The objective of the invention is also solved with the combined foundry-rolling installation according to claim 8, while the first scissors are designed for cutting a draft strip with a thickness equal to 18 mm, preferably 20 mm, with a speed of transportation of the draft strip equal to 0.5 m / from.

In order to possibly reduce the total number of scissors used in the combined casting and rolling installation, it is preferable if the first scissors are also designed to cut the casting product with a thickness of 90 mm, preferably 110 mm, at a transport speed of 0.1 m / s. Thanks to this, you can do without the so-called emergency scissors in front of the finishing group of stands.

Preferably, the first scissors, preferably pendulum scissors, are located immediately after the crimp group of stands.

Preferably, if a furnace is installed after the first scissors, preferably an induction furnace.

Preferably, if second scissors are arranged between the first scissors and the furnace, preferably drum scissors. Due to this, even in the event of a malfunction in the area of the furnace, finishing group of stands, cooling device or coiler, a continuous casting process can be supported.

For the microstructure of a section of the roughing strip, it is preferable if multistage pressure treatment is performed in the crimping group of stands.

Preferably, if immediately before the finishing group of stands the device for descaling is installed.

In addition, it is preferable that a cooling device for cooling a portion of the finished strip is installed after the finishing group of the stands.

Brief Description of the Drawings

Other advantages and features of the present invention are contained in the following description of non-limiting embodiments, with reference to the following figures, in which:

figure 1: a schematic representation of a combined foundry-rolling installation for implementing the method of the invention;

figure 2: simplified in comparison with figure 1 combined casting and rolling installation for implementing the proposed invention the method.

Description of Embodiments

Figure 1 shows a schematic representation of a combined foundry-rolling installation 1, which is made in the form of the so-called installation of ESP (Endless Strip Production - endless strip production) for the manufacture of strip steel. In the continuous endless mode, on the machine 2 for continuous casting, molten steel is cast to obtain thin slabs, while the thickness of the continuous ingot immediately after the mold is 90 mm. In a continuous ingot support device installed after the crystallizer, a partially solidified continuous ingot by means of a so-called Liquid Core Reduction (rolling strip with a still liquid core) is thinned to a thickness of 70 mm. After the casting unit 2, the fully hardened casting product passes in the conveying direction 5 through a three-stand crimping group 3 of the stands, where the continuous ingot is thinned to obtain the so-called roughing strip 4 or, accordingly, rolled with a thickness of 19 mm. After crimping, the rough strip 4 uncut passes through the first scissors 6, which are made in the form of pendulum scissors, the input and output device 15 through the gateway and the second scissors 13, which are made in the form of drum scissors. After that, the draft strip 4 is heated in the induction furnace 12 to the rolling temperature, so that the heated draft strip 4 after descaling in the descaling device 14 is rolled in the austenitic region of the structure in stands 7a ... 7d of the finishing group 7 stands to obtain the finished strip 8 or, respectively, the finished tape. After finishing rolling, the finished strip 8 with a thickness of 4 mm is cooled in the cooling device 9 to the winding temperature and then wound into a riot in one of the winders 10a, 10b. Quick scissors, which are located between the cooling device 9 and the coilers 10a ... 10b, for cutting the finished strip 8 to the desired riot weight, are not shown for illustrative purposes.

The commissioning of the combined foundry-rolling plant 1 due to the insufficient experience of the personnel in commissioning is difficult, since the commissioning of the plant in a connected mode, i.e. when a crimp group of 3 stands is connected with a finishing group of 7 stands by means of a roughing strip 4, it places high demands on automation.

Commissioning in accordance with the invention is as follows: after the commissioning of the continuous casting machine, it is suitable for casting thin slabs. With the subsequent commissioning of the crimping group of 3 stands, it becomes suitable for crimping a thin slab to obtain a roughing strip 4; it is preferable if the crimping group 3 stands is at least partially loaded with a thin slab from the machine 2 for continuous casting. When commissioning the first scissors 6, they become suitable for cutting the roughing strip 4. Although - as described above - with continuous endless operation, the casting product, roughing strip 4 and finished strip 8 pass through the combined casting and rolling unit 1 uncut (to the transverse cutting of the finished lanes 8 for the desired riot weight), the commissioning of the first scissors 6 ensures that, on the one hand, intermittent (for example, the so-called Batch - periodic) mode is possible, and a proper response to cases is possible faults in the combined casting and rolling installation 1. When commissioning finishing group stands 7 uncut continuously manufactured blister strip 4, i.e., the casting product compressed in the crimping group of 3 stands is cut by means of the first scissors 6 to obtain a section of the draft strip, and before the head part of the draft strip 4 enters the first stand 7a of the finishing group 7 of the stands. Then, a section of the draft strip on the rolling table 11, which interconnects all parts of the installation between the continuous casting machine 2 and the coilers 10a, 10b, is accelerated in the direction of the finishing group 7 by stands, not shown in detail, so that the tail section of the draft strip after acceleration is at a distance of 1 to 5 from the uncut roughing strip 4. A section of the roughing strip is then rolled in the finishing group of 7 stands for several rolling passes (for example, three rolling passes in four etevoy finishing group stands 7) to obtain the segment of the finished strip. When cooling a section of a finished strip in a cooling device 9, a section of a finished strip is cooled to a winding temperature before a section of a finished strip in one of the coilers 10a, 10b is wound into a so-called micro-riot (eng. “Micro-coil”). Preferably, the length of the draft strip has a weight of at least 5 tons, so that the length of the finished strip can be wound on commercially available coilers 10a, 10b. In accordance with the invention, the section of the draft strip in the finishing group of 7 stands is thinned to obtain a section of the finished strip so that the length of the rolled section of the finished strip> is greater than the path of the finished tape or, accordingly, the section of the finished tape between the finishing group 7 of the stand and the coiler 10a, 10b . This guarantees the possibility of creating sufficient belt tension, so that a good direction of the finished strip in the subsequent parts of the installation is ensured and the quality of the wound material is improved. During the first rolling passes during the commissioning of the finishing group 7 stands it can be preferable to roll a section of the roughing strip only in the temperature state of the casting process, i.e. without additional heating in the induction furnace 12 and at the same time usually in the ferritic region of the structure, for a maximum of three steps of thinning in the finishing group of 7 stands. In subsequent rolling passes during commissioning, an induction furnace 12 can be used to heat the length of the roughing strip to the rolling temperature, so that finish rolling can take place in the austenitic region of the structure. The first scissors 6 are preferably made in the form of pendulum scissors, and these pendulum scissors are designed both for cutting the casting product with a thickness of 90 mm, and for cutting a draft strip with a thickness of 18 mm, with a speed of transportation of the draft strip of 0.5 m / s

Figure 2 shows a simplified image compared to figure 1, which is also suitable for implementing the method of the invention.

Specifically, the invention proposed method has the following advantages compared with the prior art:

- reducing complexity during commissioning of the finishing group of stands, due to which a smaller number of rolling defects is achieved (English cobbles),

- reducing the duration and cost of commissioning, and

- already at commissioning, the sale of riots received is possible.

Item Specification

1 Combined foundry-rolling installation

2 Foundry

3 Crimp stand group

4 Draft strip or, respectively, a segment of the draft strip

5 Direction of transportation

6 First scissors

7, 7a ... 7d Finishing group of stands

8 Finished strip or, respectively, a segment of the finished strip

9 Cooling device

10, 10a ... 10b Winder

11 Roller

12 Oven

13 Second scissors

14 Descaling device

15 Gateway input and output device.

Claims (13)

1. The method of rolling strips in a combined casting and rolling installation containing a finishing group (7) of the stands of a rolling mill, including continuous casting of liquid metal, preferably steel, to obtain a casting product in a casting installation (2), crimping the casting product to obtain a rough strip ( 4) in the crimping group (3) stands, characterized in that the cutting of the roughing strip (4) is carried out to obtain a segment of the roughing strip by means of the first scissors (6) before the head of the roughing strip (4) is included in the finishing group (7) stand, and there is cutting of the roughing strip (4) with a thickness equal to 18 mm, preferably 20 mm, with a transportation speed of 0.5 m / s, finishing rolling of a section of the roughing strip in the finishing group (7) with a stand to obtain a section of the finished strip and winding a section finished strip in a coiler (10). 2. The method according to claim 1, characterized in that the segment of the draft strip is accelerated on the roller table (11) in the direction of the finishing group (7) of the stands. 3. The method according to claim 1, characterized in that the length of the segment of the finished strip is greater than the length of the path of the tape between the finishing group (7) of the stand and the coiler (10). 4. The method according to claim 1, characterized in that a section of the finished strip is cooled in a cooling device (9) to a winding temperature. 5. The method according to claim 1, characterized in that the segment of the roughing strip is heated in the furnace (12) to a rolling temperature before the finish rolling, preferably by induction. 6. The method according to claim 5, characterized in that the section of the draft strip after heating is subjected to descaling in the device (12) for descaling. 7. The method according to claim 1, characterized in that the specific gravity per unit width of the segment of the casting product is more than 3.5 t / m, preferably more than 4.5 t / m. 8. Combined casting and rolling installation comprising a casting installation (2) for casting liquid steel to obtain a casting product, preferably a thin slab, a crimping group (3) stands for crimping the casting product to obtain a draft strip (4), while the crimping group ( 3) the stand is installed after the foundry plant (2), the first scissors (6) for cutting the roughing strip (4) to obtain a segment of the roughing strip, the first scissors (6) installed after the crimping (3) group of stands, the finishing group (7) of the stands for finishing rolling of a draft section moss to obtain a segment of the finished strip, while the finishing group (7) of the stands is installed after the first scissors (6), and the winder (10) for winding a segment of the finished strip, while the winder (10) is installed after the finishing group (7) of the stand, characterized the fact that the first scissors (6) are intended for cutting a draft strip (4) with a thickness of 18 mm, preferably 20 mm, with a transport speed of 0.5 m / s, and, if necessary, also for cutting the casting product with a thickness of 90 mm, preferably 110 mm, with a transport speed of 0.1 m / . 9. Installation according to claim 8, characterized in that the first scissors (6), preferably pendulum scissors, are located immediately after the crimping group (3) stands. 10. Installation according to claim 8, characterized in that after the first scissors (6) a furnace (12) is installed, preferably an induction furnace. 11. Installation according to claim 10, characterized in that between the first scissors (6) and the furnace (12) are second scissors (13), preferably drum scissors. 12. Installation according to claim 8, characterized in that a device (14) for descaling is installed in front of the finishing group (7) of the stands. 13. Installation according to claim 8, characterized in that the cooling device (9) for cooling a section of the finished strip is installed after the finishing group (7) of the mill.

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