WO2015014864A1 - Casting and rolling plant and method for producing slabs - Google Patents

Abstract

The invention relates to a casting and rolling plant having a strip-casting machine and to a method for producing near-net strips. In addition to the strip-casting machine for casting a cast strand, the casting and rolling plant comprises shears 130 for separating the cast strand into slabs of predetermined length, a temperature-homogenization device 140 and also a Steckel rolling mill to roll the slabs to form near-net strips with a predetermined thickness. In order to make it possible to construct the casting and rolling plant in more compact form and at the same time to make it possible for the production method to be more economical in terms of time and energy, the invention proposes that a multi-roller smoothing device 120 is arranged between the output of the strip-casting machine 110 and the temperature-homogenization device 140 in the casting and rolling plant, and that a roller table is provided between the output of the temperature-homogenization device and the Steckel rolling mill to feed the slabs directly into the Steckel rolling mill (160).

Description

 Cast rolling mill and method for producing slabs

The invention relates to a casting and rolling plant with a strip casting machine and a method for producing pre-strip. Specifically, the invention relates to small caster rolling mills, so-called micromill plants, for the production of flat steel with an annual production between 350,000 and 700,000 t of carbon steel. The plant concept according to the invention is characterized by low investment and production costs, rapid project implementation with a short return on investment and a compact plant layout. The plant according to the invention is particularly suitable for steel producers in regions where so far no flat steel production took place and where a specialization to regional requirements should take place.

Cast rolling with strip casting machines are known in the art in principle. A comprehensive overview of the basics of strip casting, which is still valid today, can be found in the article by Spitzer et al., Development status in the DSC strip casting process, Stahl and Eisen 121 (2001) No. 5. DSC stands for Direct Strip Casting. From this article strip casting machines are known with a cooled conveyor belt and wherein the range from the steel task to hot rolling is housed, so that a protective gas atmosphere can be adjusted. The casting machine described there has a casting speed of up to 60 m / min. and produces a cast strand with a casting thickness of 8 to 15 mm. The strip casting machine downstream is a roller table and after the roller table follows a continuous in-line rolling. The rolling stand allows a reduction in thickness z. B. to 8 mm. After rolling, the steel strip is wound into a coil. Further state of the art casting toggle systems with strip casting found for. In DE 197 58 108 C1 or in WO 201 1/061262 A1.

Similarly, WO 2010/066412 A1 discloses a casting and rolling plant with a strip casting machine. The strip casting machine follows in the casting direction a roller table with a temperature homogenization zone, a temperature setting device, a mass flow control, a second temperature setting device and a rolling stand, a pair of scissors and a reel. A disadvantage of this continuous in-line rolling device is that the slab in the rolling mill can only be subjected to a single pass and thus only a reduction in thickness before it is wound up as a pre-strip on the reel.

An alternative plant concept with a strip casting machine is known from the European patent EP 1 827 720 B1. Specifically, this patent discloses a caster in which follow after the strip casting a temperature homogenizer, a roughing stand, a pair of scissors and a first take-up device in the casting direction. To further reduce the thickness downstream of a Steckel mill is provided in the casting direction and the Steckel rolling mill below a cooling section and finally a coiler. To operate the Steckel mill, it is necessary that the coils produced by means of the first coiler be implemented in a first winding furnace located upstream of the Steckel mill before the metal strip of the coil can first pass through the Steckel mill for a first pass. Although the implementation of the coils or metal strips allows a temporary storage of coils or metal strips in a warehouse; However, this interruption of the casting-rolling process time and energy is lost, the latter in particular because the coils may need to be reheated in the winding furnace before entering the Steckel mill. Based on this prior art, the invention has the object, a casting and a method for producing slabs with the help of a strip casting machine in such a way that the casting rolling mill can be made more compact and that in the manufacturing process time and energy can be saved. The object is achieved by the device technology by the claimed in claim 1 casting rolling. This is characterized in that a Multirollenglätteinrichtung is arranged between the output of the strip casting machine and the temperature homogenizer and that a roller table is provided between the output of the temperature homogenizer and the Steckel mill for feeding the slabs directly into the Steckel mill.

In the context of the present description, the word "Gießstrang" is used for the cast product between the mold and the scissors, the word "slab" for the cast product between the scissors and the Steckel mill and the word "Vorband" for the cast product between the Steckel mill and the reel The claimed system design offers the advantage that the slabs can be introduced directly into the Steckel mill downstream of the temperature homogenizer, where they can be subjected to a first pass without the slabs being wound up beforehand Pre-scaffolding is not foreseen and is not required By saving the roughing stand and a take-up device for winding the slabs from the temperature homogenizer, the plant can be made more compact and investment costs can be saved In addition, this system concept is very energy efficient, because no appreciable temperature losses occur between the temperature homogenizer and the Steckel mill, for example, by interim storage or wrapping of coils, as is known from the prior art. According to a first embodiment of the invention, the Steckwalzwerk upstream and downstream, in each case based on the casting direction, winding furnaces, so-called Steckel assigned. Both Steckel each have only one winding device and are each only designed to wind the pre-strip after a pass of the Steckel mill and for dispensing the pre-strip to the Steckel mill for the subsequent stitch. In particular, the winding furnace arranged upstream is not designed to receive the slabs, for example, from the temperature homogenizing device. He has for this purpose no second winding device or no second station, which would allow the winding of the slabs from the temperature homogenizer and which would further allow the implementation of the coils thus produced for feeding the slabs to the Steckel mill.

The shears for dividing the cast strand cast by the casting machine into slabs of predetermined length may be disposed between the multi-roll smoother and the entrance of the temperature homogenizer or between the exit of the temperature homogenizer and the Steckel mill.

Between the output of the temperature homogenizer and the Steckel mill, an induction heating device is preferably arranged for heating the slabs to a temperature suitable for the Steckel rollers.

The above object of the invention is further achieved by the method claimed in claim 9. The advantages of this process solution correspond to the advantages mentioned above with respect to the claimed cast roll mill. The method provides that the casting strand with a casting belt speed of 5 to 25 m / min. is poured. The method according to the invention and the associated cast roll plant according to the invention are in particular provided for producing carbon steel pre-strips.

Further advantageous embodiments of the claimed casting and the claimed method are the subject of the dependent claims.

The invention is a total of 2 figures attached, wherein

FIG. 1 shows the cast roll mill according to the invention; and FIG. 2 shows the strip casting machine according to the invention in detail.

The invention will be described in detail below with reference to the said figures in the form of embodiments. In both figures, the same technical elements are designated by the same reference numerals.

FIG. 1 shows the casting and rolling plant 100 according to the invention. It comprises a melt feeding system 105, a strip casting machine 10, a multi-roll smoothing device 120, a shear 130, a temperature homogenizing furnace 140, optionally an induction heating device 150, a roller table 155, a Steckel rolling mill 160, a cooling section 170 and, for example, a reeling device 180. Below, the individual components of the cast rolling mill will be described at least partially in detail. The melt delivery system 105 consists essentially of a refractory lined or separately dumped position Heatable melt container, which the liquid metal, ie the melt, via a discharge nozzle using gravity on the conveyor belt 1 18, see Figure 2, the strip casting machine 1 10 performs. A fill level measuring system, not shown in FIG. 1, ensures a constant melt level in the melt container and thus a constant flow of melt to the strip casting machine 10. The distribution of the melt over the casting width takes place via flow guidance elements (not shown in FIG. 1) in the melt delivery system 105 or via arranged guide systems. These guide systems can conduct the melt with the aid of electromagnetic traveling fields or by the use of gas, which is passed through nozzles on the melt surface. The combination of several melt container with each other is possible. The flow guidance elements also extend beyond the melt delivery system into the region of the circulating conveyor belt 1 18 of the strip casting machine 10.

The strip casting machine 10, as shown in FIG. 2, consists essentially of the optionally textured or coated transport belt 1 18 revolving around three rollers. The transport belt 118 is preferably made of steel with a thickness of less than 3 mm. The smaller of the three rollers 1 15 shown in Figure 2 ensures a uniform tension of the tape. The laterally delimiting the strip caster take over two horizontally encircling water-cooled dam block chains, not shown in FIG. The conveyor belt is cooled from below via spray nozzles, also not shown in FIG. 2, in the melt feed region with specific water-loading densities between 80 and 300 l / s / m ² . Until the belt outlet the Wasserbeaufschlagungsdichten be returned to values between 10 and 100 liters / sec / m ² . By virtue of the spray-cooling container, which is arranged almost airtight beneath the belt and comprises the rollers 15 and support grids, the belt cooling is operated with preferably> 100 m / bar negative pressure. The outside prevailing air pressure thus ensures the flat pressing of the metal strip on the support means between the two large rollers 1 15th The strip casting machine 1 10 according to the invention has a strip contact length of less than 7.5 m, wherein the strip contact length is measured as the distance between the centers of the two large rollers 1 15. The realized with the strip casting machine 1 10 casting speeds are, depending on the casting thickness between 5 and 25 m / min.

The strip casting machine 1 10 is the Multirollenglätteinrichtung 120 downstream in the casting direction R. In the multi-roll smoothing device 120, the cast strand is guided to improve its flatness with at least three pairs of rolls 124. The pairs of rollers are preferably driven individually. A reduction in the thickness of the casting strand generally does not take place in the multi-roll smoothing device.

The example subsequent scissors 130 cuts the cast strand in slabs of predetermined length and decouples the previous casting process from a subsequent rolling process.

In the casting direction R behind the multi-roll smoothing device 120, preferably also behind the shear 120, the temperature homogenizer 140 is arranged, which is typically designed as a tunnel furnace. The inductive heating downstream of the furnace, which is provided only as an option, optionally provides for an increase in the temperature of the slabs and / or for a temperature compensation over the length of the slab before the slabs enter the downstream Steckel mill (160). The Steckel mill produces the desired final thickness with three, five, seven or more passes. The Steckel mill (160) is followed, as already mentioned above, in the casting direction by the cooling section 170 and the reel 180 for winding the pre-strips into a collar 250.

From a process engineering point of view, the casting roll plant according to the invention thus formed has the advantage that the slabs, after passing through the temperature homogenizing device 140, are transported directly into the Steckel mill 160, substantially without loss of time and energy or heat loss Perform a first pass without having to be wound up first. At most, the induction heater 150 and / or the scissors 130 are arranged between the temperature homogenizer 140 and the Steckel mill 160.

LIST OF REFERENCE NUMBERS

100 cast rolling mill

 105 melt task system

 1 10 strip casting machine

 1 15 big rolls

 1 18 coated conveyor belt

 120 multi-roll smoothing device

 124 three pairs of rolls

 130 scissors

 140 temperature homogenizer

150 induction heating

 155 roller table

 160 Steckel mill

 162 winding furnace

 164 winding furnace

 170 cooling section

 180 reel device

 200 cast strand

 210 slabs

 220 opening band

 250 francs

 R casting direction

Claims

Claims 1. Casting mill (100) with  a strip casting machine (110) for casting a cast strand (200); a pair of scissors (130) for cutting the cast strand into slabs (210) of predetermined length;  a temperature homogenizer (140); and  a Steckel mill (160) for rolling the slabs to Vorbändern (220) of predetermined thickness;  characterized,  that between the output of the strip casting machine (1 10) and the temperature homogenizer (140) a  Multi-roll smoother (120) is arranged; and  that a roller table is provided between the outlet of the temperature homogenizer and the Steckel mill for feeding the slabs directly into the Steckel mill (160). 2. Cast rolling mill (100) according to claim 1,  characterized in that  the Steckel rolling mill (160) upstream and downstream winding furnaces (162, 164) each have only one winding device and are each only designed to wind the Vorbandes from the Steckel mill (160) and for discharging the Vorbandes to the Steckel mill. Casting rolling mill (100) according to one of the preceding claims; characterized in that between the outlet of the temperature homogenizer (140) and the Steckel rolling mill (160) an induction heating device (150) is arranged. 4. Cast rolling mill (100) according to one of the preceding claims,  characterized in that  the multi-roll smoothing device (120) has at least 3 pairs of rolls (124), of which at least one pair of rolls is driven. 5. Cast rolling mill (100) according to one of the preceding claims,  marked by  a cooling section (170) downstream of the Steckel mill. 6. Cast rolling mill (100) according to claim 5,  marked by  a reeling device (180) downstream of the cooling section (170). 7. Cast rolling mill (100) according to one of the preceding claims,  characterized,  the strip casting machine (110) has a strip contact length of less than 7.5 m. 8. Cast rolling mill (100) according to one of the preceding claims,  characterized in that  the shears (130) for cutting the cast strand into slabs  predetermined length between the Multirollerglätteinrichtung (120) and the input of the temperature homogenizer (140) or between the output of the temperature homogenizer (140) and the Steckelwalzwerk (160) is arranged. 9. Method for producing slabs with the following steps: Producing a cast strand (200) by tape casting; Homogenizing the temperature of the cast strand (200);  Splitting the cast strand before or after homogenizing in  slabs;  Inserting the slabs into a Steckel mill (160); and  Reducing the thickness of the slabs in the Steckel mill by at least 3 passes to a desired thickness to a pre-strip (220);  characterized,  that the cast strand (200) is smoothed before its temperature is homogenized; and  that after the temperature homogenization, the slabs are introduced directly into the Steckel mill (160) and there subjected to the first pass before they are first fed to a winding furnace of the Steckel mill. 10.A method according to claim 9,  characterized,  that the casting speed of the cast strand is between 5 and 25 m / min. 1 1 .Method according to claim 9 or 10,  characterized,  that the slabs after the temperature homogenization, but before their entry into the Steckel mill (160) are again preferably heated inductively. 12. The method according to any one of claims 9 to 1 1,  characterized,  that the cast strand before entering the Steckel mill in Slabs of predetermined length is divided. 13. The method according to any one of claims 9 to 12,  characterized,  that the cast strand (200) consists of carbon steel. 14. The method according to any one of claims 9 to 13,  characterized,  that the cast strand (200) is cast with a casting thickness between 10 and 20 mm. 15. The method according to any one of claims 9 to 14,  characterized,  that the pre-bands are cooled after their outlet from the Steckel mill. 16. The method according to claim 15,  characterized,  that the pre-tapes, after being cooled, are wound up into a collar (250).