EP0593002B1 - Method and device for rolling of hot wide strip of continuously cast thin stabs - Google Patents

Description

The invention relates to a method and a system for rolling out hot wide strip from continuously cast thin slabs in successive steps of a rolling line having a continuous finishing train, casting strands being produced in one or more casting machines or casting lines, separated from these individual thin slabs and each being homogenized in a compensating furnace Bring temperature and introduced into a compensation zone with storage or buffer and occasionally to the formed movable furnace part of the compensation furnace and from this via a storage furnace arranged in the rolling line and occasionally an additional holding furnace into the rolling line.

If thin slabs are not wound after casting, they need a relatively long furnace. For example, a standard furnace system for two or three casting strands guides the thin slabs straight ahead and transversely to the rolling mill. Such a system is described for example in EP 0 438 066 A2. This has for rolling out hot wide strip from continuously cast thin slabs by means of a continuous finishing train on three upstream casting machines or casting lines, the middle casting machine being in line with the finishing train. The transfer of the thin slabs from the cast strands to the finishing train is carried out by two ferries working as combined longitudinal / transverse / longitudinal transport systems, in which they are alternately placed in alignment with two adjacent cast strands running side by side.

• daß die Ladezeit für eine von einem Gießstrang abgetrennte Dünnbramme in das Längs /Quer /Längs- Transportsystem der Entladezeit einer solchen Dünnbramme aus dem Transportsystem entspricht und
• daß die Walzzeit für die Auswalzung einer Dünnbramme jederzeit größer ist als die Fahrzeit der Längs /Quer /Längs- Transportsysteme zuzüglich dieser Lade- bzw. Entladezeit.

By designing the plant in this way, a significant reduction in the cycle times for feeding the hot broadband finishing train with thin slabs can be achieved if the conditions are met.

• that the loading time for a thin slab separated from a casting strand into the longitudinal / transverse / longitudinal transport system corresponds to the unloading time of such a thin slab from the transport system and
• that the rolling time for rolling out a thin slab is always greater than the travel time of the longitudinal / transverse / longitudinal transport systems plus this loading and unloading time.

In this system, it has proven to be important that each casting machine is assigned an oven, a compensation area and a buffer area in front of the longitudinal / transverse / longitudinal transport systems, while an in-line receiving oven is arranged downstream of the transport systems in front of the finishing train.

In the known system concept, on the other hand, the advantage that can be achieved by shortening the cycle times for loading the finishing train is adversely affected by the great length of the furnace system. It is approximately 210 m and requires high investment costs both for the furnace system and for a correspondingly long hall construction.

In order to reduce the investment and the space requirement and to improve the temperature control, EP 0 413 169 A1 proposed a system concept for the production of steel strip with one or more steel strip casting systems and temperature compensation furnaces arranged downstream of these. This provides that the finishing mill is arranged opposite to the outfeed direction of the steel strip caster with a lateral offset, whereby in addition to the temperature compensation furnace conveying in the discharge direction of the steel strip caster, a further temperature compensation furnace is arranged opposite in the direction of the finish rolling mill, and the temperature compensation furnaces arranged next to one another are connected by a transverse transport device at the end.

With this system concept, the furnace length is shortened to almost half, but it has the disadvantage that the furnace dwell time from the beginning and end of the slab is increased due to the difference in casting and intake speed due to the change of direction. Another difficulty arises from the fact that the furnace system is led through the casting system must become.

The invention is based on the object of specifying a method of the type specified in the preamble of claim 1 and a system suitable for carrying it out, by means of which the furnace system is shortened compared to a rolling method or a straight-line rolling system, without this resulting in process engineering disadvantages or arrangement-related difficulties arise.

The object is achieved in a method for rolling out hot wide strip from continuously cast thin slabs of the type mentioned at the outset in that, in a first step, a thin slab is pivoted out of a casting line or displaced laterally using a movable furnace part and after a first reversal of direction in the opposite direction Conveyed cast strand and introduced into a storage furnace within the rolling line and in a second step from this after a second reversal of direction in a holding furnace downstream of the storage furnace in the direction towards the rolling line and fed from the holding furnace into the finishing train and rolled into the end product.

With the method according to the invention, a significant shortening of the furnace system is achieved by reversing the material flow twice and at the same time procedural disadvantages are avoided. In contrast to the simple change of direction of the material flow there are no additional differences in the dwell time of the strip end and strip head, except for the inevitable system-related difference that is caused by the difference between the casting and rolling speeds. While a furnace system for straight running with transverse transport has a length of between 210 and 180 m, the length of a furnace system suitable for carrying out the method according to the invention with a double change of direction is 125 to 130 m.

One embodiment of the method provides that a thin slab is introduced within its casting line into a swiveling furnace part designed as a roller hearth swiveling furnace and swiveled with it into an oblique switch division in the direction towards the rolling line and the storage furnace of the rolling line, likewise designed as a swiveling furnace, in the direction against the Casting line is pivoted by the same angular amount in an opposite inclined switch position, such that both pivot furnaces connect in a straight line with their free ends to each other, the thin slab is introduced after a first reversal of direction in the opposite direction to the casting in the storage furnace of the rolling line designed as a pivot furnace and both swiveling furnaces are swiveled back into their starting positions, and finally the thin slab is transferred after a second change of direction from the storage furnace and via the downstream holding furnace into the finishing train w earth

Another embodiment provides that one Thin slab is introduced within its casting line into a movable part of the roller hearth furnace designed as a ferry and initially moved laterally out of the casting line towards the rolling line by a partial amount of the center distance of the two lines and then also the storage furnace designed as a ferry against the laterally displaced roller hearth furnace is also offset by a partial amount of the center distance of the two lines, in such a way that the two furnaces are connected in a straight line with their ends facing one another and the thin slab is introduced into the storage furnace after a first reversal of direction in the opposite direction to the cast strand, whereupon both furnaces are returned to their starting position be driven back and the thin slab, after reversing the direction again, is transferred from the storage furnace to the subsequent holding furnace and from there to the finishing train.

And finally, a further embodiment of the method provides that a thin slab is introduced within its casting line into a movable part of the roller hearth furnace designed as a swing arm swivel and swiveled with it into the space between the casting line and the rolling line and the storage furnace also designed as a swing arm swivel the rolling line is pivoted into the space between the rolling line and the casting line against the movable part of the roller hearth furnace, in such a way that the two furnaces are connected in a straight line with their ends facing each other and the thin slab after a first reversal of direction The opposite direction to the cast strand is introduced into the storage furnace, whereupon both furnaces are pivoted back into their starting position and the thin slab is transferred from the storage furnace into the subsequent holding furnace and from there into the finishing train after the direction has been reversed again.

A system for rolling out hot wide strip from continuously cast thin slabs by means of a rolling line which has a continuous finishing train, this at least two casting machines or casting lines with means for separating individual thin slabs from the cast strands produced, and in each case with a compensating furnace with an arranged there as a store, buffer or Moving furnace parts designed to compensate for carrying out the method according to the invention are characterized in that a storage furnace is arranged in the rolling line and that the furnaces have means for mutual connection when transferring thin slabs from a casting line into the rolling line and with direction reversal means for the transport of the thin slabs are formed, and that a holding furnace is arranged downstream of the storage furnace.

Overall, the layout of the system results in a considerable shortening of the furnace system and thus the overall system, this advantage being achieved by the special arrangement and design of the system elements for a two-way reversal of the material flow, without requiring a greater technical outlay than with a system for straight running with cross transport.

Appropriate configurations of the system are provided in accordance with the features of the subclaims. Further details, features and advantages of the invention result from the following explanation of the exemplary embodiments shown schematically in the drawings.

Fig. 1

eine CSP- Anlage mit zwei Stranggießmaschinen, einer Fertigstraße und mit einer Ofenanlage für zweifache Richtungsumkehr beim Materialfluss,

Fig. 2

eine CSP- Anlage gemäß Fig. 1 mit einer anderen Ausgestaltung der Ofenanlage,

Fig. 3

eine CSP- Anlage gemäß Fig. 1 mit einer anderen Ausgestaltung der Ofenanlage,

Fig. 4

eine CSP- Anlage mit drei Gießlinien und einer eine Fertigstraße aufweisenden Walzlinie,

Fig. 5a - 5c

CSP- Anlagen mit zwei Gießsträngen und einer in Linie mit einem Gießstrang angeordneten Walzenstraßen.

Show it:

Fig. 1

a CSP system with two continuous casting machines, one finishing train and one furnace system for double reversal of direction in the material flow,

Fig. 2

1 with a different configuration of the furnace system,

Fig. 3

1 with a different configuration of the furnace system,

Fig. 4

a CSP system with three casting lines and a rolling line with a finishing train,

5a-5c

CSP systems with two casting lines and one roller line arranged in line with one casting line.

The plant shown in FIGS. 1 to 3 for rolling out hot wide strip from continuously cast thin slabs has a rolling line (x-x) with a continuous finishing train (7). With parallel offset, two casting machines or casting lines (1, 2) are assigned to this. Each casting machine (1, 2) is followed by a pair of scissors (4, 5) for separating individual thin slabs from the continuously cast cast strand. In the casting line (1) there is a compensating furnace (10) with a movable furnace part (13) of the compensating furnace (10) arranged there as a storage, buffer or compensator, and in the casting line (2) a compensating furnace (11) a downstream movable furnace part (14) designed as a store, buffer or compensation. In the rolling line (xx) is a storage furnace (16) at a distance parallel to the compensating furnace (10) of the casting line (1) with its roll-side end (25) flush or approximately flush with the roll-side ends (26, 27) of the Compensation furnaces (10, 11) arranged. The furnace parts (13, 14) and the storage furnaces (16) interacting with them have means for mutual connection for the transfer of thin slabs from a casting line (1, 2) to the rolling line (xx) and are equipped with direction reversal means for the transport of the thin slabs educated. An expedient embodiment results from the fact that a holding furnace (20) is arranged downstream of each storage furnace (16) in the rolling line (x-x).

In the embodiment shown in FIG. 1, the movable parts (13, 14) of the equalizing furnaces (10, 11) and the storage furnace (16) are each as Roller hearth swivel furnaces are formed and arranged longitudinally offset from one another by approximately one swivel furnace length. The pivot points (30, 31) of the pivoting furnaces (13, 14) are arranged at their rear ends and the pivot point (32) of the pivoting furnace (16) at its front end such that one of these pairs of furnaces (13, 16) or . (14, 16) in a pivoting position of the same kind, in the opposite manner, interacting to form a straight transition for the material transport of a thin slab from a casting line (1, 2) to the rolling line (xx).

Another embodiment of the system according to FIG. 2 provides that the movable part (13a, 14a) of a compensating roller hearth furnace (10a, 11a) and the storage furnace (16a) as ferries with means for longitudinal and / or transverse movement of a thin slab are designed such that each pair of furnaces (13a, 16a) or (14a, 16a) in a mutually transverse position in the space between a casting line (1, 2) and the rolling line (xx) with their mutually facing ends adjoining one another in a straight line Form the transition for the transport of a thin slab from the ferry (13a) or (13b) into the storage furnace (16a) and thus from a casting line to the rolling line. The thin slab is transported from the ferry (13a) into the storage furnace (16a) in the opposite direction to the casting direction. As soon as the thin slab has completely moved into the storage furnace (16a) designed as a ferry, it is traversed in the rolling line (xx) and the thin slab is transferred from the storage furnace (16a) to the downstream holding furnace (20a) and out of it if necessary into the rolling train (7a) while accelerating to the insertion speed.

In a configuration of the system in accordance with the example shown in FIG. 3, the movable part (13b, 14b) of a compensating roller hearth furnace (10b, 11b) and the storage furnace (16b) are each designed as parallel swivels or generally as four-bar swivels with crank-arm swiveling devices , in such a way that a pair of furnaces (13b, 16b) or (14b, 16b) in a position swiveled out by 90 ^o or 180 ^o depending on the swivel system with their mutually facing ends in the space between a casting line (1, 2) and the rolling line Connect (xx) to each other. They form a straight transition for the transport of a thin slab from a casting line (1, 2) to the rolling line (xx). In this position of the two furnaces, a thin slab is then transferred from the pivoted furnace part (13b) into the counter-pivoted storage furnace (16b), after which both furnaces (13b, 16b) and (14b, 16b) are pivoted back into the starting position. The thin slab is then transferred from the storage furnace (16b) into the subsequent holding furnace (20b) and finally into the rolling train (7b).

A further embodiment of the installation according to FIG. 4 provides that the rolling line (xx) is assigned a further casting installation (3) and that a shortened roller hearth compensation furnace (12) with a subsequent swiveling or parallel displaceable furnace part (16c) is arranged downstream, on which one Holding furnace (20c) or an extended holding furnace (20c, 21) connects.

• 1. Länge einer Ofenanlage für Geradeauslauf mit Quertransport 180 bzw. 210 m.
• 2. Länge einer Ofenanlage mit zweifachem Richtungswechsel 125 bis 130 m.

The shortening of the furnace system proposed according to the invention is achieved by means of two-way reversal of direction. Compared to a furnace system with a straight outlet, there are no procedural disadvantages. In addition to ferries, other movement elements such as swivel with a fulcrum, parallel swivel or generally crank swivel swivel / four-joint swivel are possible and can be carried out without difficulty. Overall, there is a considerable reduction in plant. If you compare the length of the system according to the invention with types of furnace systems for straight-ahead operation, the following lengths result for the same specifications:

• 1. Length of a furnace system for straight running with cross transport 180 or 210 m.
• 2. Length of a furnace with a double change of direction 125 to 130 m.

The shortening of the furnace system and thus also the hall construction is achieved according to the invention with known and proven means, without this requiring additional expenditure on system elements.

The invention relates not only to CSP systems which are to be operated as double-line systems in the first construction stage, ie in which, as in the above exemplary embodiments, the Rolling mill is arranged centrally to two parallel casting machine strands / furnace strands. With a significant proportion of CSP systems, a second casting line / furnace line is only provided in the second construction stage. In the first construction stage, the rolling mill is therefore planned in line with the casting machine / furnace system. A second casting strand / furnace strand is only added in the second construction stage. A system concept created in this way in the second stage of expansion is shown in FIGS. 5a to 5c; the present invention is also applicable to this. However, because there are only two working lines in this case, it is advisable to carry out the material return only from the second strand. This also has the advantage that only two swivels / ferries / crank arm swivels are required for this. This system concept also leads to a considerable shortening of the system. FIGS. 5a to 5c show similar basic plant concepts, in which, in the last stage of expansion, two parallel casting machine lines (I) and (II) each in the usual arrangement, each with a pair of scissors (4a to 4c), (5a to 5c) each one downstream Equalization furnace (100a to 100c) or (110a to 110b), a further downstream storage furnace (101a to 101c) or (111a to 111c) and an extended furnace part (102a to 102c) or (112a to 112c) are available as holding furnace , followed by the roller mills (70a to 70c).

A storage furnace (101a) to (101c) of the casting machine line (I) and a holding furnace (112a) to (112c) of the casting machine line (II), be it as a simple swivel (Fig. 5a), as a ferry (Fig. 5b) or as a swing arm swivel (Fig. 5c) and in pairs (101a, 112a) or ( 101b, 112b) and (101c, 112c) are assigned to each other so that the respective pair of furnaces, in cooperation at the end of their movement, have means for mutual connection for the transfer of a thin slab from the casting line (II) into the casting line (I) and thus in the holding furnace (102a to 102c) of the roll train (70a to 70c). Because of this arrangement, the method can then be carried out in accordance with the technical teaching of claim 1.

Claims (11)

1. Method for the rolling-out of hot wide strip from continuously cast thin slabs in successive working steps of a rolling line comprising a continuous finishing train (7, 70), wherein cast strands are produced in several casting machines (1, 2; I, II) or casting lines and individual thin slabs are severed off from these and respectively homogenised in a compensating furnace (10, 11, 110, 111) and brought to temperature and are introduced into a movable part (13, 14, 112), which is constructed as storage device, buffer or compensation, of the compensating furnace (10, 11) or of the compensating furnace part (111) and are transferred out of this by way of a storage furnace (16, 101) arranged in the rolling line (x-x) and occasionally a prolonged holding furnace (20, 21) into the rolling line (x-x), characterised thereby, that a thin slab is pivoted or displaced laterally out of a casting line and after a first reversal of direction conveyed in opposite direction to the cast strand and introduced into a storage furnace (16, 101) within the rolling line (x-x) with the use of a movable furnace part (13, 14, 112) in a first working step and conveyed out of this after a second reversal of direction into a holding furnace (20, 21 or 102), which is arranged downstream of the storage furnace (16, 101), in the direction against the rolling line (x-x) and introduced out of the holding furnace (20, 21 or 102) into the finishing train (7, 70) and rolled out into the end product therein in a second working step.
2. Method according to claim 1, characterised thereby, that one thin slab at a time is introduced within its casting line into a movable furnace part (13, 14, 112) constructed as pivotal roller hearth furnace and pivoted by this into an oblique shunt setting in the direction against the rolling line (x-x) and the storage furnace (16, 101), which is likewise constructed as pivotal furnace, of the rolling line (x-x) is pivoted in the direction against the casting line by the same angular amount into an equal and opposite oblique shunt setting in such a manner that both pivotal furnaces (13, 16; 14, 16; 101, 112) each time adjoin one the other in rectilinear connection by their free ends, whereafter the thin slab is conveyed after a first reversal of direction in opposite direction to the cast strand into the storage furnace (16, 101), which is constructed as pivotal furnace, of the rolling line (x-x) and both furnaces are pivoted back into their initial settings and the thin slab is finally after a second reversal of direction transferred out of the storage furnace (16, 101) as well as by way of the holding furnace (20, 21 or 102) downstream thereof into the finishing train (7, 70).
3. Method according to claim 1, characterised thereby, that one thin slab at a time is introduced within its casting line into a movable part, which is constructed as ferry (13a or 112b), of the roller hearth furnace and displaced by this initially out of the casting line towards the rolling line (x-x) by a partial amount of the axial spacing of both the lines, then the storage furnace (16 or 101b), which is constructed as ferry, is likewise displaced towards the laterally displaced roller hearth furnace by a partial amount of the axial spacing of both the lines in such a manner that both furnaces adjoin one the other in rectilinear connection by their mutually facing ends and the thin slab is introduced after a first reversal of direction in opposite direction to the cast strand into the storage furnace (16 or 101b), whereupon both furnaces are moved back again to their initial position and the thin slab is transferred, after reversal of direction once again, out of the storage furnace (16 or 101b) into the holding furnace (20 or 102) adjoining thereat and from this into the finishing train (7).
4. Method according to claim 1, characterised thereby, that one thin slab at a time is introduced within its casting line into a movable part, which is constructed as pivoting device (13b, 14b or 112), of the roller hearth furnace and pivoted by this into the gap between the casting line and the rolling line (x-x) and the storage furnace, which is likewise constructed as pivoting device (16b or 101c), is pivoted out of the rolling line (x-x) into the gap between the casting line and the rolling line (x-x) towards the movable part of the roller hearth furnace in such a manner that both furnaces adjoin one the other in rectilinear connection by their mutually facing ends and the thin slab is introduced after a first reversal of direction in opposite direction to the cast strand into the storage furnace (16b or 101c), whereupon both furnaces are moved back again to their initial position and the thin slab is transferred, after reversal of direction once again, out of the storage furnace (16b or 101c) into the holding furnace (20b or 102c) adjoining thereat and from this into the finishing train (7, 70).
5. Plant for the rolling-out of hot wide strip from continuously cast thin slabs by means of a rolling line comprising a continuous finishing train (7, 70), wherein this line is associated with at least two casting machines (1, 2; I, II) or casting lines with means (4, 5) for tha severing of individual thin slabs from the cast strands produced as well as with a respective balancing furnace (10, 11; 100, 110) and a movable furnace part (13, 14; 101, 112), which is arranged thereat and constructed as storage device, buffer or compensation, for the performance of the method according to one or more of the preceding claims, characterised thereby, that a storage furnace (16, 101, 111) is arranged in the rolling line (x-x), that at least one furnace part (13, 14, 101, 112) as well as the storage furnace (16, 101, 111) cooperating therewith comprise means for the mutual connection for the transfer of one slab at a time from a casting line (1, 2; I, II) into the rolling line (x-x) and are provided with direction-reversing means for the transport of the thin slabs and that a holding furnace (20, 102, 112) is arranged downstream of the storage furnace (16, 101, 111).
6. Plant according to claim 5, characterised thereby, that the storage furnace (16) of the rolling line (x-x) is arranged at a spacing from and parallelly to the balancing furnace (10, 11; 100, 110) of the casting line (1) and by its end (25) at the roll side flush or nearly flush with the ends (26, 27), which are at the roll side, of the or each balancing furnace (10, 11).
7. Plant according to one or both of the claims 5 and 6, characterised thereby, that the movable part (13, 14, 101) of the balancing furnace (10, 11; 100, 11) and the storage furnace (16) or the holding furnace (112a) are each constructed as pivotal roller hearth furnace and arranged to be longitudinally displaced one relative to the other by about one pivotal furnace length, wherein the pivot points (30, 31) of the pivotal furnaces (13, 14, 101) are arranged at their rear ends and the pivot point of the storage furnace (16) or the holding furnace (112a) is arranged at its front end in such a manner that one of these furnace pairs (13, 16 or 14, 16 or 101, 112) each time co-operating in an equal and opposite pivotal position in the manner of a shunting switch form a rectilinear transition for the transport of a thin slab from a casting line (1, 2) to the rolling line (x-x).
8. Plant according to one or both of the claims 5 and 6, characterised thereby, that the movable part (13a, 14a) of a compensating roller hearth furnace (10a, 11a) as well as the storage furnace (16a) are each constructed as ferries with means for the longitudinal and/or transverse movement of a thin slab in such a manner that one furnace pair (13a, 16a or 14a, 16a) each time, in a position one moved transversely against the other in the gap between a casting line (1, 2) and the rolling line (x-x) and adjoining one against the other by their mutually facing ends, forms a rectilinear transition for the transport of a thin slab out of the ferry (13a or 13b) into the storage furnace (16a) and thus from a casting line (1, 2) to the rolling line (x-x).
9. Plant according to one or both of the claims 5 and 6, characterised thereby, that the movable part (13b, 14b) of a compensating roller hearth furnace (10b, 11b) as well as the storage furnace (16b) are each constructed as parallelly pivotable devices with crank throw and pivoting equipments in such a manner that one furnace pair (13b, 16b or 14b, 16b) each time in outwardly pivoted setting adjoin one the other rectilinearly by their mutually facing ends in the gap between a casting line (1, 2) and the rolling line (x-x).
10. Plant according to one or both of the claims 5 and 6, characterised thereby, that the rolling line (x-x) is associated with a further casting plant (3) and that arranged downstream thereof there is a shortened compensating roller hearth furnace (12) with a pivotable or parallelly displaceable furnace part (16a), which is adjoined by a holding furnace (20c) or a prolonged holding furnace (20c, 21).
11. Application of the method according to claim 1 to a modified CSP plant with two parallel casting machine strands or furnace plant strands with a rolling train arranged in line with one of the casting machine strands or furnace plant strands.

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