EP0045400A1 - Installation for direct-strand reduction of steel at high velocities - Google Patents

Abstract

1. Installation for the casting-rolling of steel at high speeds, in which the continuously produced cast length is completly solidified, after passing through a temperature-equalisation path (4 and 4a) is fed to a pre-rolling section (7) and thereupon rolled in several intermediate and final rolling sections (14, 16, 17), before it is subjected in bar or wire form to further treatment operations, characterized by two mutually independent casting apparatuses (1 and 1a) each consisting of a casting machine (2 and 2a) with a secondary cooling path (3 and 3a), following temperature-equalisation path (4 and 4a) and a guillotine (6 and 6a), and by a prerolling section (7) movable transversely of the casting direction (double arrow 13), which can be driven according to choice into the region of the longitudinal axis (12 and 12a) of one of the two casting apparatus (1 and 1a).

Description

The invention relates to a method and a plant for the casting-rolling of metals, in particular steel, at high speeds, at which the continuously produced casting strand completely solidifies and, after passing through a temperature compensation section, is fed to a roughing mill and subsequently interposed and in several rolling mills is finish-rolled before being subjected to further treatment processes in the form of a rod or wire.

When casting steel for the production of rod or wire material, it is necessary to work with relatively small cross sections at high casting speeds for economic reasons; for example, a casting and rolling plant with a theoretical output of 65 t / h should have a casting cross section of approximately 160 mm x 90 mm exhibit; resulting in a casting speed of 10 m / min. results. Casting larger cross-sections while maintaining the same theoretical performance inevitably leads to lower casting speeds. Too low a casting speed, however, results in rod or Wire lines too low feed speeds in the first rolling stands of the rolling line, which is connected downstream of the casting machine producing the casting strand. The rolls of the roll stands in question are consequently subjected to very high thermal loads and wear out disproportionately quickly.

Working with smaller casting cross sections and higher casting speeds has the further advantage that the roughing train downstream of the casting machine requires a smaller number of roll stands; this leads to a considerable reduction in investment costs and energy requirements. However, the increase in the casting speed is disadvantageous in that the length of the metallurgical section, especially when casting steel, becomes very long. If the casting machine and the associated primary cooling section are followed by a temperature compensation section, the length of which also increases with the size of the casting speed, such a casting and rolling system has a considerable space requirement in the area between the casting machine and the first roll stand.

In addition to the difficulties described _/ caused by the operating conditions, the combination of casting machine and rolling mill always leads to less good output; in the event of a failure of the casting machine or the rolling mill, the other sub-system fails or can no longer work economically.

Casting and rolling systems have so far only been successfully used for wire production from non-ferrous metals. This is mainly due to the fact that the Solidification length for non-ferrous metals is considerably less than for steel; the rolling mill can consequently be arranged at a short distance behind the casting machine, which leads to an acceptable overall length of these non-ferrous casting rolling plants.

Casting and rolling systems for steel for casting relatively large casting cross sections have also become known, which have a roughing mill arranged directly behind the secondary cooling section of the casting machine. This arrangement was intended to shorten the solidification length and to distribute and close non-metallic inclusions and cavities in the cast strand more evenly. However, the excessive deformation of the liquid strand core during the pre-rolling caused such high stresses that cracks formed in the strand core which prevented further deformation.

In view of these disadvantages, most of the previously known casting and rolling systems for steel are operated decoupled again, i.e. the casting strand is cut to length after complete solidification and, after a brief reheating by rolling, it is reduced in cross section to such an extent that it is suitable as a starting material for a wire or fine steel mill.

The invention has for its object to provide a method and a system for casting rolling, in particular steel, which allow a high output with relatively low investment costs.

The method and the system should also be designed so that the particularly high Casting speeds required space is reduced.

The stated object is achieved by a system of the type mentioned at the outset, which has the features of claim 1.

The idea of the solution on which the invention is based then consists in equipping the casting and rolling plant with two mutually independent complete casting sections, to which a single roughing mill movable transversely to the casting direction is optionally assigned. The second casting line is put into operation in the event of failure of the other casting line, so that the downstream rolling mill can continue to work with a short interruption. In addition to the cost savings due to the use of only one roughing mill, the displaceable arrangement of the roughing mill has the advantage that the casting strand can be introduced into the mill stands of the roughing mill without being deflected.

Within the scope of the invention, each casting section can additionally be equipped with a drive unit; this is located behind the temperature compensation section, advantageously in the area between the latter and the subsequent shear.

Advantageously, the plant according to the invention is further designed in such a way that a 180 ^o- deflection unit is arranged in the region between the roughing mill and the rolling treatment final finishing train, which determines the direction of movement of the cast strand during the further treatment processes. The 180 ° deflection unit is in any case arranged in an area behind the roughing mill, that is to say in an area in which the cross section of the pre-rolled casting strand has no particular difficulties with. the deformation associated with the deflection. By redirecting the casting strand and returning it within of the rolling mill, the length of the casting and rolling system may be reduced by up to 50%; This not only leads to a reduction in the length of the hall, but also to a reduction in the installation costs for the oil, water, air, hydraulic and electrical supply to the casting and rolling system.

If the newly proposed system has two intermediate streets downstream of the primary street, the 180 ° deflection unit is at most behind the second intermediate street (claim 3); Depending on the operating conditions, it can also be expedient to arrange the 180 ° deflection unit between the two intermediate streets.

To reduce the effort required for the sliding drive, the rolling stands of the roughing mill can be moved with respect to their fixed rolling drive (claim 5).

In a particularly preferred embodiment of the subject matter of the invention, the rolling stands of the roughing mill are each arranged on their own sliding frame and connected to their rolling drive via cardan shafts (claim 6).

If the casting and rolling plant is to be used for wire production, it preferably also has the features of claim 7 and / or claim 8.

The process for casting metal rolling is essentially characterized in that it has the characteristics of Claims 9 and / or 10.

It consists, therefore, of diverting the casting strand after passing through the roughing train, but at the latest before entering the finishing train, by an angle of 180 ° and maintaining the changed direction of movement opposite to the casting direction during the subsequent treatment processes. The method can furthermore be designed such that the casting strand - which is optionally produced from different casting sections - reaches its effective area by moving the roll stands of the roughing train transversely to the casting direction.

The invention is explained in detail below using an exemplary embodiment shown in the drawing.

• Fig. 1 schematisch den Aufbau der erfindungsgemäßen Gießwalzanlage und
• _Fig. 2 schematisch den Aufbau eines quer zur Gießrichtung verschiebbaren Walzgerüstes der in Fig. 1 dargestellten Vorstraße.

Show it:

• Fig. 1 shows schematically the structure of the casting and rolling plant according to the invention
• _F ig. 2 schematically shows the construction of a roll stand which can be moved transversely to the casting direction of the roughing train shown in FIG. 1.

The casting and rolling system according to the invention (cf. or 5a and a pair of cutting scissors 6 and 6a.

The casting lines 1 and 1a, which are preferably constructed in this way, are followed by a single roughing line 7 common to both casting lines, which in the exemplary embodiment shown is composed of three roll stands 8, 9 and 10. The roughing mill 7 can be moved transversely to the casting direction (arrow 11) such that it lies either in the region of the longitudinal axis 12 of the casting section 1 or in the region of the longitudinal axis 12a of the casting section 1a. The two above-mentioned operating positions, in which the preliminary road 7 is assigned to the casting line 1 or the casting line 1a, are denoted in the drawing with solid lines or with dash-dotted lines; the transverse displaceability of the Vorstraße 7 is to be indicated by a double arrow 13.

The use of two mutually independent casting sections 1 and 1a is intended to ensure that the production of the casting and rolling system can be maintained in the event of a casting section failure, in particular a casting machine. The casting machines 2 and 2a are designed in a manner known per se; they can in particular consist of two casting belts delimiting a casting cross section or of a casting wheel which interacts with a suitably designed casting belt.

The liquid steel to be processed is cast into a casting strand in one of the two casting machines - for example in the casting machine 2 - and there it receives an approximately 10 to 20 mm thick shell. In the subsequent secondary cooling section 3, the casting strand solidifies under the influence of an intensive one Water cooling completely through, in the temperature compensation section 4, the temperature gradient between the strand shell and the strand core is reduced and, if necessary, the casting strand back to rolling temperature. temperature is heated.

The two casting lines 1 and 1a are connected by the rolling mill, which consists of the aforementioned roughing mill 7, a first intermediate mill 14, a 180 ° deflection unit 15, a second intermediate mill 16, a finishing mill 17, a primary cooling section 18, a winding layer 19, one Secondary cooling section 20 and a collecting station 21. The casting strand pre-rolled in the roughing mill 7 and reduced to a suitable cross-section is further deformed in the intermediate streets 14 and 16 before it receives the desired wire cross-section when passing through the finishing train 17. In the area between the roughing train and the finishing train 17 7 - in the illustrated embodiment, between the two intermediate trains 14 and 16 - passes through the cast strand, the deflection unit 180 ^0- 15; he thereby receives a movement direction 22 opposite to the casting direction 11, which remains during the subsequent treatment processes. After the finish rolling, the casting strand runs, for example in wire form, through the primary cooling section 18 of the rolling mill, is turned into turns by means of the winding layer 19 and is guided over the secondary cooling section 20 of the rolling mill before it is collected into wire rings in the collecting station 21.

The deflection of the casting strand - which, depending on the cross section, can be carried out before, between and after the two intermediate streets 14 and 16 - leads to one Significant reduction in space requirements and installation costs for the supply equipment of the casting and rolling plant.

The displaceable arrangement of the roughing road 7 makes deflection of the casting strand, which still has the full casting cross section in this area, superfluous.

In FIG. 2, the roll stand 8 of the roughing mill lying in front in the casting direction is an example. 7, which can be moved back and forth in the direction of the double arrow 13. The schematically represented rollers 8 ′ and 8 ″ are connected to a gear 24 by means of cardan shafts 23 and, with the interposition of a clutch 25, to a motor 26 serving as a roller drive arranged.

The roll stand 8 (like the other roll stands 9 and 10 of the roughing mill 7, not shown) is movably held on a sliding frame 28 within a fixed guide 29. The displacement frame 28 is connected in an articulated manner to the piston rod 30 'of a cylinder unit 30, which serves as a displacement drive and in turn is held in a stationary manner via a bracket 31.

The sliding frame 28 of the roll stand 8 is equipped with a clamping device 32 which clamps it in the selected operating position with the guide 29 and thus holds it in place.

In the operating position shown in FIG. 2, the roll stand 8 (and the subsequent roll stands of the roughing mill) assume a position in which the roll center 33 coincides with the longitudinal axis 12 indicated in FIG. 1 falls; the second operating position of the roll stand 8 is indicated by dash-dotted lines in FIG. 1.

Deviating from the construction of the rolling stands of the roughing mill 7 just explained, under certain circumstances these can also be arranged in a plurality on a common sliding frame; it is possible, for example, to arrange two successively rolling stands of the roughing mill on a common sliding frame.

The stationary arrangement of the roller drive and the displacement drive with respect to the roll stands has the advantage that the installation of these drives is simplified and the size of the masses to be moved is kept as small as possible.

The casting and rolling system and possibly the 180 ⁰ deflection unit can - in contrast to the application example shown in FIG. 1 (downstream rolling mill line) also interact with a rolling mill for the production of fine steel.

Claims (10)

1. Plant for the casting-rolling of metals, in particular steel, at high speeds, at which the continuously produced casting strand completely solidifies and, after passing through a temperature compensation section, is fed to a roughing mill and then intermediate and finish-rolled in several rolling trains before it is rolled into rod - or wire form is subjected to further treatment processes, characterized by two mutually independent casting sections (1 or 1a), each consisting of a casting machine (2 or 2a) with a secondary cooling section (3 or 3a), downstream temperature compensation section (4 or 4a) and a pair of cutting shears (6 or 6a), and through a roughing mill (7) which is movable transversely to the casting direction (arrow 11) and which either one of the two casting lines (1 or 1a) is in the area of the longitudinal axis (12 or 12a) is movable. 2. Plant according to claim 1, characterized in that a 180 ° deflection unit (15) is arranged in the area between the roughing train (7) and the finishing train (17) concluding the rolling treatment, which determines the direction of movement (arrow 22) of the casting strand during the other treatment processes. 3. Plant according to claims 1 to 2, characterized in that the Vorstraße (7) two intermediate streets (14 and 16) are connected downstream and that the 180-deflection unit (15) in front of the first intermediate street (14), but at most behind the second intermediate street (16). 4. Plant according to claim 3, characterized in that the 1800 deflection unit (15) between the two intermediate streets (14, 16) is arranged. 5. Plant according to claims 1 to 4, characterized in that the rolling stands (8, 9, 10) of the roughing mill (7) with respect to their fixed roller drive (24, 25, 26) are displaceable. 6. Plant according to claims 1 to 5, characterized in that the rolling stands (8, 9, 10) of the roughing mill (7) are each arranged on their own sliding frame (28) and via drive shafts (23) with their rolling drive (24, 25 , 26) are connected. 7. Plant for wire production according to claims 1 to 6, characterized in that the finishing train (17) at least one cooling section (18) and a winding layer (19) and a collecting station (21) follow. 8. Plant according to claim 7, characterized in that the winding layer (19) is connected upstream and a primary cooling section (18) and a secondary cooling section (20). 9. A process for the casting-rolling of metals, in particular steel, at high speeds, in which the continuously produced casting strand completely solidifies and, after passing through a temperature-equalizing section, is fed to a roughing mill and then intermediate and finish-rolled in several rolling mills before it is rolled into rod - or wire form to further treatment operations is subjected, characterized in that the cast strand after passing through the roughing train, but is deflected before entry into the finishing train at an angle of 180 at the latest, and the changed, the _G ieß- direction opposite direction of movement during the subsequent Maintains treatment processes. 10. The method according to claim 9, characterized in that the casting strand - which is optionally generated from different casting lines - by moving the rolling stands of the roughing cross to the casting direction in its effective area.

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