EP2454038B1 - Method for securing a start-up strand in a continuous casting system and continuous casting system having a start-up strand - Google Patents

Description

Technical area

The invention relates to a method for securing a starter strand in a strand guide of a continuous casting plant and a continuous casting plant with a starter strand.

• der Anfahrstrang beim Einfädeln von antreibbaren Strangführungsrollen transportiert;
• der Anfahrstrang vor dem Gießbeginn in einer, eine Kokille ausgangsseitig verschließenden, Startposition von anstellbaren Strangführungsrollen gehalten; und
• der Anfahrstrang und ein sich nach dem Gießbeginn ausbildender Gussstrang von antreibbaren Strangführungsrollen ausgezogen wird.

Specifically, the invention relates to a method for securing a starter strand in a strand guide comprising a plurality of strand guide rollers continuous casting, wherein

• the Anfahrstrang transported during threading drivable strand guide rollers;
• the dummy bar is held in a starting position of engageable strand guide rollers on the output side before the start of casting; and
• the dummy bar and a cast strand of drivable strand guide rollers forming after the start of pouring is pulled out.

Furthermore, the invention relates to a continuous casting with a mold and a subsequent strand in the conveying direction strand guide, and with a Anfahrstrang that closes the mold at the start of casting exit and can be held and moved in the strand guide of engagable and driven strand guide rollers, the strand guide rollers a transport path for form the Anfahrstrang.

State of the art

Before the start of a casting process, the mold is closed on the output side with the head of a starter strand. The Anfahrstrang is either promoted from below in an upward movement along the strand guide mostly with engagable and driven strand guide rollers to the mold and held in this starting position of the strand guide rollers or starting from the Casting platform conveyed from above through the mold and then held in the strand guide in turn by the engagable and drivable strand guide rollers in the starting position.

An operator error or failure in one - the adjusable and drivable strand guide rollers - means of electrical, hydraulic, pneumatic or communication, can lead to a sudden onset, constantly accelerating downward movement of the heavy Anfahrstrangs in the strand guide, with this movement, the so-called Crash, typically over a long distance (eg over several strand guide segments and / or traction roller scaffolding). This risk is particularly high in vertical casters, as this type of plant has a vertical strand guide. The crash of the starter train can lead to personal injury as well as damage to individual plant components. For safety reasons, operating personnel are therefore not allowed to stay in hazardous areas during this phase of operation.

To avoid such disturbances, it is from the DE 19 53 094 A1 already known to arrange a frictional locking device in Bogenstranggießanlagen in the travel of the Anfahrstrangs. Thus, the Anfahrstrang is held by a clamping in the start position until the beginning of the casting process, the Anfahrstrang is moved by the drivable and engagable strand guide rollers with the desired casting speed through the strand guide. The locking device is located in the strand conveying direction behind the straightening device in the region of the outlet roller table of the continuous casting plant. The embodiment described requires a very long Anfahrstrang and is not suitable for short Anfahrstränge or for use of different length Anfahrstränge. In addition, the use of a heavy starting line is problematic due to the clamping.

Presentation of the invention

• das Halten und das Sichern des Anfahrstrangs gegenüber einem unkontrollierten Absturz durch voneinander unabhängige Systeme erfolgt; und bei der
• das Sichern des Anfahrstrangs gegenüber einem unkontrollierten Absturz von einem separaten, vom kontinuierlichen Gießbetrieb unabhängigen, Element in der Strangführung erfolgt.

Object of the present invention is to avoid the disadvantages of the prior art described and to propose a method for securing the Anfahrstrangs in a continuous casting and a continuous casting with start-up strand, in the

• holding and securing the Anfahrstrangs against an uncontrolled crash occurs by independent systems; and at the
• securing the Anfahrstrangs against an uncontrolled crash from a separate, independent of the continuous casting operation, element in the strand guide takes place.

Another object of the invention is that the Anfahrstrang can be secured both during threading, while holding in the starting position and after the start of pouring. Furthermore, the securing of the Anfahrstrangs should be independent of the weight starter strand and in particular work well even with very heavy Anfahrsträngen.

• dass der Anfahrstrang beim Einfädeln und Halten von zumindest einer, in Strangförderrichtung nachgelagerten, Arretiereinrichtung gesichert wird; und
• dass das Sichern und Entsichern des Anfahrstrangs mittels der Arretiereinrichtung durch ein Verschließen und ein Freigeben eines von den Strangführungsrollen gebildeten Transportwegs erfolgt.

This object is achieved on the basis of a method of the type described in the introduction by

• that the starter strand is secured during threading and holding at least one, downstream in the strand conveying direction, locking device; and
• in that the securing and unlocking of the starting line by means of the locking device takes place by closing and releasing a transport path formed by the strand guiding rollers.

According to the method of the invention, the Anfahrstrang is transported during the threading of drivable strand guide rollers in the strand guide in the direction of mold and then held before the casting start in a mold on the output side closing starting position of engagable strand guide rollers. In order to prevent the crash of the Anfahrstrangs, the Anfahrstrang when threading and holding at least one in Strangförderrichtung downstream locking device secured, ie the movement of the Anfahrstrangs in the strand conveying direction is blocked by at least one locking device. As a result, the Anfahrstrang is secured both during threading, while holding and during Ausfördern against an uncontrolled crash. The securing and unlocking of the Anfahrstrangs by means of a locking device by closing and releasing a transport path formed by the strand guide rollers, whereby the securing of the Anfahrstrangs largely independent of the weight of the Anfahrstrangs.

In an advantageous embodiment, a plurality of locking devices are distributed in the strand guide (e.g., comprising one or more strand guide segments or traction roller frames) which are sequentially secured as the dummy strand is threaded and sequentially released after casting commencement. The sequential saving, i. locking, when threading, occurs opposite to the strand transport direction, whereas sequential unlocking, i. Unlocking, after the start of pouring takes place in the strand transport direction. As a result of the sequential unlocking of the locking devices, the casting operation proceeds undisturbed by securing the starter strand. In addition, the securing of the starter strand by a plurality of distributed in the strand guide, locking is largely independent of the length of the Anfahrstrangs, whereby the backup of very short Anfahrsträngen is possible. The plurality of locking devices further reduces the distance in the event of a crash until the starting line is intercepted in the strand guide, which increases safety.

In an advantageous embodiment, an arresting device automatically secures the startup line in the event of a failure of a device of electrical, hydraulic, pneumatic or communication. This increases the safety when threading, holding and unthreading the dummy bar.

In a further advantageous embodiment, the automatic securing of the starter strand without external, i. from outside the locking device, energy. This further increases the safety during threading, holding and unthreading of the dummy bar

In a sudden loosening and crashing of the starter strand of the starter strand is intercepted by a, downstream in the strand conveying direction, locking and prevented from further downward movement. This ensures that in case of a crash no operationally relevant component, in particular no segment or an engageable role, is damaged.

In order to enable the most direct implementation of the method according to the invention, which solves the problem underlying the invention, it is advantageous that at least one locking device for the Anfahrstrang is arranged in the strand guide, which lies from a lying outside the transport path release position in a transport path the Anfahrstrangs locking catch position is formed displaced back and forth. By means of this device, the Anfahrstrang is positively secured, creating a high reliability is achieved even for very heavy Anfahrstränge.

To achieve the advantages of the invention, it is irrelevant whether the caster as a vertical or curved continuous, and whether the continuous casting plant for the production of billets (English bloom.), Sticks (Engl. Billet), preliminary sections (Engl. Beam blank) or slabs (English slab ) is formed.

In addition, it does not matter if the Anfahrstrang is designed as a link chain or rigid, or has a straight or curved shape.

In an expedient embodiment, a locking device on a front side of a Strand guide segment or a drive roller frame or between two, adjacent in the strand conveying direction, strand guide rollers, preferably driven strand guide rollers arranged. Thus, the force for securing or intercepting the Anfahrstrangs is introduced via the locking device in an advantageous manner in the strand guide segment or in the drive roller frame.

Alternatively, a locking device can also be arranged in a separate support structure. By means of this embodiment, it is possible to assemble or disassemble the locking device independently of strand guide segments or driving roller stands.

A simple embodiment is to form a locking device as a displaceable or pivotable bolt, wherein the bolt is designed to be displaceable by a Betätigungsvorrichung. It is particularly advantageous to use the bolt and the actuating device in an assembly, e.g. As a cassette, form so that this module can be easily and quickly assembled or disassembled.

A further embodiment is to form a locking device as a displaceable, inclined plate or a displaceable, obliquely located bolt, wherein the weight of the locking device defines the basic position of the locking device and the locking device is displaceable via an actuating device in the release position. This ensures that the locking device automatically secures the Anfahrstrang in case of failure of the actuator.

A further embodiment consists in that the actuating device comprises a, for example pneumatic or hydraulic, pressure accumulator, wherein the pressure accumulator formed by means of a pressure medium cylinder Actuator defines the basic position of the locking device. This ensures that the locking device automatically secures the Anfahrstrang in case of failure of the actuator.

A further embodiment consists in that the actuating device comprises a spring, wherein the spring force defines the basic position of the locking device. This ensures that the locking device automatically secures the Anfahrstrang in case of failure of the actuator.

In a further advantageous embodiment, the Anfahrstrang a transverse to the transport path recess, preferably a slot or a U-shaped recess, and on the Anfahrstrang on, engaging in the recess, displaceable bolt, is secured.

An alternative embodiment is that a locking device is designed as a displaceable or pivotable plate, wherein the plate is designed to be displaceable by an actuating device.

• Fig. 1 eine schematische Darstellung des Absicherns beim Einfädeln eines Anfahrstrangs in eine Vertikalstranggießanlage mit Strangführungssegmenten
• Fig. 2 eine schematische Darstellung des Absicherns beim Halten und Ausziehens des Anfahrstrangs
• Fig. 3 eine perspektivische Darstellung eines Strangführungssegments mit einer Arretiereinrichtung zum Absichern eines Anfahrstrangs
• Fig. 4 eine schematische Darstellung des Absicherns beim Einfädeln eines Anfahrstrangs in eine Vertikalstranggießanlage mit Treibrollengerüst
• Fig. 5 eine schematische Darstellung eines Teils der Strangführung einer Vertikalstranggießanlage mit einer Arretiereinrichtung

Further advantages and features of the present invention will become apparent from the following description of non-limiting embodiments, reference being made to the following figures, which show the following:

• Fig. 1 a schematic representation of the hedging when threading a starter strand in a vertical caster with strand guide segments
• Fig. 2 a schematic representation of hedging when holding and pulling out of the Anfahrstrangs
• Fig. 3 a perspective view of a strand guide segment with a locking device for securing a starter strand
• Fig. 4 a schematic representation of the hedging when threading a starter strand in a vertical caster with drive roller frame
• Fig. 5 a schematic representation of a portion of the strand guide a vertical caster with a locking device

In Fig. 1 is a vertical caster in a longitudinal section with the essential components of the invention shown schematically. It comprises a mold 1, in which a cast strand of molten steel is formed during the casting process, and an adjoining vertical strand guide 2, in which the cast strand is continuously cooled, guided and supported. The strand guide is formed by a series of strand guide segments, of which four strand guide segments 3a, 3b, 3c, 3d are shown as representative. The transport path 6 for the dummy bar 4 and the cast strand through the strand guide 2 is formed by two rows of strand guide rollers 7a and 7b, which are grouped together and stored in the strand guide segments 3a to 3d. A series of strand guide rollers 7a are fixedly supported on the outside of the strand guide segment and the second series of strand guide rollers 7b are arranged on the inside of the strand guide segment so as to be movable relative to the first series of strand guide rollers. This relative mobility allows, for example, the adjustment to a desired strand thickness or a reduction in thickness in a cast strand with, for example, still liquid core. As in Fig. 3 shown in more detail, the outer and the inner strand guide rollers 7a and 7b are rotatably supported in a support frame. Some of the strand guide rollers 7a, 7b are designed as drivable strand guide rollers 7c and / or as engageable strand guide rollers 7d and determine the speed of the casting strand or the withdrawal speed of the starter strand 4. To close the mold 1 before the casting start of the continuous casting on the output side, a starter strand 4th from below into the Threaded strand guide 2. To secure the Anfahrstrangs 4, the strand guide segments 3b to 3d each have a locking device 8a to 8c. The different phases of threading are in FIG. 1 marked with the numbers 1 to 4.

In phase 1, the continuous casting plant is shown at the beginning of the threading process. In this case, all locking devices 8a, 8b, 8c are opened, the dummy bar 4 is threaded from below into the strand guide segment 3d and moved by means of drivable and / or adjustable strand guide rollers 7c, 7d against the strand transport direction R.

In phase 2, the Anfahrstrang 4 has already passed the strand guide segment 3d and the locking device 8c has been closed, whereby the Anfahrstrang is secured against falling. Subsequently, the Anfahrstrang is in turn moved by means of drivable and / or engageable strand guide rollers 7c, 7d and secured by means of the locking device 8b in phase 3 and 8a in phase 4.

In phase 4 of the Anfahrstrang has reached the starting position for the casting start, whereby the head of the Anfahrstrangs 4 closes the mold 1 on the output side.

In an embodiment not shown, of course, the Anfahrstrang can also be threaded from above, ie from the casting platform, through the mold in the strand guide (eng., Top feeding ) . In this case, the Anfahrstrang is usually introduced by a movable on the casting platform Anfahrstrangwagen or a crane through the mold and lowered to a locked locking device. Afterwards the crane is suspended from the starting line, so that any incorrect operation is excluded. Furthermore, the drivable and / or engageable strand guide rollers are turned on and the Anfahrstrang accurately positioned in the strand guide and the locking device again locked. Also in this embodiment, it is advantageous, depending on the length of the Anfahrstrangs at least one locking device to keep closed during threading and so to secure the Anfahrstrang.

In Fig. 2 is holding the Anfahrstrangs 4 and the extraction of the Anfahrstrangs 4 with the casting 5 from the mold 1 shown. In phase 1, the starting line is held by the drivable and / or engageable strand guide rollers and secured by the locking device 8a. After the start of casting, the locking device 8a is unlocked, ie unlocked, and the starter strand 4 with the forming cast strand 5 from the mold 1 in the strand conveying direction R pulled out. For this purpose, the locking devices 8a to 8c of the successive strand guide segments 3b, 3c, 3d are subsequently sequentially unlocked, whereby the starting and the casting strand are secured even when pulling out.

In Fig. 3 a strand guide segment 3 a strand guide a vertical caster is shown. The strand guide segment consists essentially of a support frame 12, the outer and inner strand guide rollers 7a, 7b, and the locking device 8, which comprises a displaceable on the upper end face 9 of the strand guide segment 3 executed plate 9 and a, designed as a pressure cylinder actuation device 11. The outer, arranged in strand transport direction R bottom, strand guide roller 7c is designed as a drivable strand guide roller. The also arranged below, but internal strand guide roller 7d is designed as a, by means of an adjusting device 13 designed as a hydraulic cylinder, as engageable strand guide roller. As a result, the strand guide rollers 7b, 7d in the support frame 12 are designed to be movable relative to the strand guide rollers 7a, 7c, making it possible to adjust to the starting or casting strand or to reduce the thickness of the cast strand. When securing the Anfahrstrang the plate 10 is the Arretiereinrichtung 8 moved by means of the actuator 11 from a lying outside the transport path 6 release position in a transport path blocking catchment position. The pressure cylinder of the actuator operates against a - the starting position of the plate over the transport path 6 defining position - not shown spring, so that the plate in case of failure of a hydraulic, electrical or communication device automatically in the starting position, ie via the transport path 6, is moved.

In Fig. 4 is a schematic representation of the threading of a starter strand 4 in a formed from a driving pulley frame strand guide 2 shown. In phase 1 is the - launched either by means of a crane through the mold 1 in the strand guide 2 ( top feeding ), or from below by means of engagable and driven strand guide rollers 7c, 7d introduced dummy bar 4 on the locked, designed as a bolt , Arretiereinrichtung 8c on. In phase 2, the engageable and drivable strand guide rollers 7c, 7d employed, possibly suspended the crane, the locking device 8c unlocked and the Anfahrstrang 4 accurately positioned. In phase 3, the launch line has the target position, cf. reached the start position above, and executed as a bolt locking device 8c is displaced by means of an actuating device, not shown in a slot of the Anfahrstrangs. In phase 4, therefore, the starting line is completely secured in the starting position.

In Fig. 5 is a part of the strand guide a vertical caster shown. In this case, the threaded starter strand 4 is held by engageable and drivable strand guide rollers 7c, 7d and, as soon as the starter strand has reached the starting position, is secured by a locking device 8 designed as a bolt in cassette construction. The actuator for the locking device 8 is as hydraulic Pressure medium cylinder executed, whereby the Anfahrstrang is automatically secured by the area ratio of the pressure medium cylinder in conjunction with a hydraulic pressure accumulator, not shown. Due to the design of the locking device in cassette construction also a quick assembly and disassembly is possible.

LIST OF REFERENCE NUMBERS

1

mold

2

strand guide

3, 3a ... 3d

Strand guide segment

4

dummy

5

cast strand

6

transport

7a, 7b

Strand guide roller

7c

drivable strand guide roller

7d

adjustable strand guide roller

8a ... 8c

locking

9

Front side of the strand guide segment

10

plate

11

actuator

12

Support frame of the strand guide segment

13

Adjustment devices on the strand guide segment

R

Strand transport direction

Claims (13)

1. Method for securing a start-up strand (4) in a strand guide (2) of a continuous casting installation which comprises a plurality of strand guide rollers (7a, 7b), wherein

   - the start-up strand (4) is transported by drivable strand guide rollers (7c) as it is being threaded in;

   - before the start of casting, the start-up strand (4) is held by settable strand guide rollers (7d) in a starting position which closes a mold (1) on the output side; and

   - the start-up strand (4) and a cast strand (5) which forms after the start of casting are extracted by drivable strand guide rollers (7c);

   - wherein the start-up strand (4) is secured by at least one locking device (8, 8a, 8b, 8c) arranged downstream in the strand conveying direction (R) as it is being threaded in and held; and

   - wherein the start-up strand (4) is secured and released by means of the locking device (8, 8a, 8b, 8c) by closing and opening a transport path (6) formed by the strand guide rollers (7a, 7b, 7c, 7d);

   characterized
   in that a plurality of locking devices (8, 8a, 8b, 8c) are distributed in the strand guide (2) and are secured in sequence as the start-up strand (4) is being threaded in and released in sequence after the start of casting.
2. Method according to Claim 1, characterized in that, if an electrical, hydraulic, pneumatic or communication device fails, a locking device (8, 8a, 8b, 8c) automatically secures the start-up strand (4), for example by an inclined plate (10) or an inclined pin, wherein the dead weight of the locking device defines an interception position of the locking device and the locking device can be displaced into a release position via an actuating apparatus (11).
3. Method according to one of the preceding claims, characterized in that, if the start-up strand (4) is suddenly detached and crashes, the start-up strand is trapped by at least one locking device (8, 8a, 8b, 8c), arranged downstream in the strand conveying direction (R), and prevented from making a further downward movement.
4. Continuous casting installation having a mold (1) and a strand guide (2), which follows in the strand conveying direction and comprises a plurality of strand guide rollers (7a, 7b), and having a start-up strand (4), which closes the mold (1) on the output side during the start of casting and which can be held and moved in the strand guide (2) by drivable and settable strand guide rollers (7c, 7d), wherein the strand guide rollers (7a, 7b) form a transport path (6) for the start-up strand (4), characterized in that a plurality of locking devices (8, 8a, 8b, 8c) for the start-up strand (4) are arranged distributed in the strand guide (2) and are each designed such that they can be displaced back and forth from a release position, which lies outside the transport path (6), into an interception position, which blocks the transport path (6) of the start-up strand (4).
5. Continuous casting installation according to Claim 4, characterized in that the continuous casting installation is in the form of a vertical continuous casting installation.
6. Continuous casting installation according to Claim 4, characterized in that the continuous casting installation is in the form of a bow-type continuous casting installation.
7. Continuous casting installation according to one of Claims 4 to 6, characterized in that a locking device (8, 8a, 8b, 8c) is arranged on a front side (9) of a strand guide segment (3, 3a, 3b, 3c) or of a driving-roller stand or between two strand guide rollers (7a, 7b) which are adjacent in the strand conveying direction (R).
8. Continuous casting installation according to one of Claims 4 to 7, characterized in that a locking device (8, 8a, 8b, 8c) is arranged in a separate support structure.
9. Continuous casting installation according to one of Claims 4 to 8, characterized in that a locking device (8, 8a, 8b, 8c) is in the form of a displaceable or pivotable pin, the pin being designed such that it can be displaced by an actuating apparatus (11).
10. Continuous casting installation according to one of Claims 4 to 9, characterized in that a locking device (8, 8a, 8b, 8c) is in the form of a displaceable, inclined plate (10) or a displaceable, inclined pin, wherein the dead weight of the locking device defines the interception position of the locking device (8, 8a, 8b, 8c) and the locking device can be displaced into the release position via an actuating apparatus (11).
11. Continuous casting installation according to one of Claims 4 to 10, characterized in that the actuating device (11) comprises a pressure accumulator, the pressure accumulator defining the interception position of the locking device (8, 8a, 8b, 8c) by means of an actuating device (11) in the form of a pressure-medium cylinder.
12. Continuous casting installation according to one of Claims 4 to 10, characterized in that the actuating device (11) comprises a spring, the spring force defining the interception position of the locking device (8, 8a, 8b, 8c).
13. Continuous casting installation according to one of Claims 4 to 12, characterized in that a locking device (8, 8a, 8b, 8c) is in the form of a displaceable or pivotable plate (10), the plate being designed such that it can be displaced by an actuating apparatus (11).

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