EP1697070B1 - Sequential casting method for the production of a high-purity cast metal billet - Google Patents
Sequential casting method for the production of a high-purity cast metal billet Download PDFInfo
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- EP1697070B1 EP1697070B1 EP04819582A EP04819582A EP1697070B1 EP 1697070 B1 EP1697070 B1 EP 1697070B1 EP 04819582 A EP04819582 A EP 04819582A EP 04819582 A EP04819582 A EP 04819582A EP 1697070 B1 EP1697070 B1 EP 1697070B1
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- Prior art keywords
- tundish
- metal melt
- supply
- melt
- quasi
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/116—Refining the metal
- B22D11/118—Refining the metal by circulating the metal under, over or around weirs
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/103—Distributing the molten metal, e.g. using runners, floats, distributors
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
- B22D11/181—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level
- B22D11/183—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level by measuring molten metal weight
Definitions
- the invention relates to a Sequenzg tell compiler for continuously producing a cast high-purity metal strand from a molten metal, preferably a molten steel, wherein the molten metal from a melt vessel regulated supplied to a distribution vessel and controlled by this distribution vessel is discharged into a continuous casting mold and wherein the supply of molten metal in the distribution vessel is interrupted during the change of the melt vessel, while the supply of the molten metal is continued in the continuous casting mold.
- Sequence casting refers to a casting process in which multiple lots of metal delivered to the caster in multiple melt vessels are continuously potted into a single metal strand without interrupting the casting process. It is necessary to replace the melt vessel after emptying it against another filled melt vessel in the shortest possible time. Forcibly, there is an interruption of the melt flow into the distribution vessel and it is necessary to measure the remaining amount in the distribution vessel so that a sufficient amount of residual metal melt to bridge the required change time in the distribution vessel is in stock, from the placed in the casting position further melt vessel again molten metal in the distribution vessel can flow. In order to maintain the continuous casting process over the change time, it is common to reduce the casting speed of the casting machine during the changeover time. With a ladle turret, the changeover time can be kept very short.
- the continuous casting itself can be equipped with a mold of any type, such as one or more oscillating plate or tube molds, with caterpillars, with molds with circumferential bands or molds are formed by rotating casting rolls with lateral Dämmrentn.
- the cross-sectional format of the metal strand to be cast can be arbitrary, but arise especially in the production of thin metal strips with strip thicknesses below 6.0 mm and bandwidths over 800 mm special requirements for the start phase or restart phase of the casting process after a ladle change, because in particular because of the relatively small melt pool and the virtually invariable metallurgical length to the kissing point in a two-roll casting, as well as the rapid solidification of a thin metal strand a significant reduction of Casting speed is not possible.
- the invention relates to the casting of a metal strip with a two-roll caster according to the vertical two-roll casting process.
- the liquid metal is usually supplied from a ladle via at least one intermediate vessel or distribution vessel of a cooled mold in which the solidification process of the molten metal to a metal strand is at least initiated.
- the transition of the molten metal from the ladle into the distribution vessel and from this further into the mold takes place predominantly through dip tubes or shadow tubes, which dive into the melt pool of the respective downstream vessel in the stationary casting operation and thus a calmed and even flow and forwarding of the molten metal as far as possible allow the mold.
- the molten metal accumulated in the ladle, the intermediate vessel and optionally in the mold is covered by a slag layer, by which the metal bath surface is protected from oxidation.
- the object of the invention is therefore to avoid these disadvantages and difficulties of the known prior art and to propose a Sequenzg tell Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoff Kunststoffets, a metal strand of high purity can be poured, where further this bridging phase in the continuous casting process can be kept as short as possible and at least the effects of non-stationary casting phases, as the melt vessel change, as soon as possible decay.
- the inflow rate in the distribution vessel is greater than the outflow rate from the distribution vessel and wherein during 70% to 100%, preferably during 70% to 99%, especially during 70% to 95%, of this period, the inflow rate in the distribution vessel is less than or equal to twice, preferably less than or equal to 1.5 times, the outflow rate from the distribution vessel.
- the minimum inflow rate into the tundish within this period of time is very much dependent on the reduction in casting speed on the caster during the melt vessel change.
- the inflow rate into the tundish during this period should be at least 0.5 times the maximum steady state inflow rate.
- distributed vessel is here not limited to the receiving vessel for molten metal, through which the transfer or distribution of molten metal is made possible in a mold, thus directly preceded by a mold, but may include all melt vessels between the ladle and the mold.
- a shortening of the resumption phase of the casting process and a maximum secure opening of the melt container is achieved without affecting the quality of the cast product, when the supply of molten metal immediately with resumption of the supply of melt into the tundish during 0.1% to 30%, preferably during 3% to 15 %, the time taken to reach the quasi-stationary RadioLiteadorOLD In the distribution vessel with maximum inflow rate and the supply of molten metal then takes place until reaching the quasi-stationary RadioLiteledge
- maximum filling rate is to be understood as meaning that the supply of molten metal into the distributor vessel takes place at maximum opening of the ladle slide, that is to say at the maximum possible filling rate. This also prevents freezing of the ladle slide opening in the Ang manphase or a significant narrowing of the flow opening and thus an undesirable reduction in the flow rate is avoided.
- the reduced filling rate does not necessarily represent a constant value over the remaining filling time until the quasi-stationary operating bath level height is reached, but rather follows a continuous or stepwise decreasing time course, as a result of which the flow conditions in the distributor vessel steadily settle during the filling time.
- the supply of molten metal is even interrupted in the distribution vessel with reaching the quasi-stationary Radiolabakadorière for a certain period of time.
- the closing of the pan slide after reaching the quasi-stationary Radiolabakador admirados has the advantage that existing foreign inclusions, especially non-metallic inclusions, quickly float at the bath level and can be deposited in the cover slag.
- the short-term interruption of the supply of melt is a good way to increase the quality of the molded product, while at the same time ensuring that the opening of the pan valve is guaranteed after this calming and deposition phase.
- the period of interruption of the supply of melt is between 1 second and 2 minutes, preferably between 10 seconds and 70 seconds, since the bath level begins to drop again as a result of the metal flowing out of the continuous casting mold.
- a covering agent is usually applied to the melt bath already at the beginning of the first casting sequence. This covering agent is retained over all casting sequences in the distribution vessel.
- the covering in the vicinity of the dipping into the molten metal shadow tube is not - even partially - along the outer wall of the shadow tube is drawn into the molten metal, it is useful if a shadow tube immediately surrounding area of the free bath surface in the distribution vessel of the cover with a covering at least during quasi-stationary operation, preferably constantly, kept free or shielded.
- shielding means which are formed by wall elements which either dip from above into the melt bath or protrude from below from the melt bath and surround the shade tube at a distance. This purposefully creates a "hot spot" around the shadow tube and it is expedient if the wall elements form a closed chamber in which the shadow tube is integrated and the atmosphere enclosed in the chamber is rendered inert.
- the supply of molten metal is briefly interrupted again to calm the bath movement in addition to increase the deposition rate of foreign particles
- this supply of molten metal in the distribution vessel regulated in quantity as a function of the removal of the molten metal from the distribution vessel.
- the transfer of the molten metal from the distribution vessel into the downstream mold begins in time with the resumption of the supply of molten metal into the distribution vessel.
- the quasi-stationary operating bath level or the corresponding distributor weight is largely maintained at a constant level.
- the amount of molten metal supplied to the tundish and the amount of molten metal discharged from the tundish is, when casting a steel strip, at a casting thickness of 1.0 - 5.0 mm and a casting width of 1.0 m to 2.0 m, between 0 , 5 t / min and 4.0 t / min, preferably between 0.8 t / min and 2.0 t / min.
- This information refers to the use of a two-roll casting machine with the desired cast product of appropriate design.
- the capping agent is applied to the bath surface of the molten metal in the tundish in a surface area of low surface flow rate, waviness of the bath surface, and turbulence intensity.
- a case by case manual task of the cover requires sufficient accessibility of the distribution vessel for the operator and also brings the disadvantage of additional Schlackeneinsch flows through the sudden local task of a larger amount of the covering with it.
- the covering agent is therefore applied in fine-grained form or in powder form, preferably with a semi-automatic or fully automatic feeding device.
- the interior of the distribution vessel is shielded by a distributor cover against the free atmosphere, wherein it is expedient that during or before the Rouzllphase an inerting of the distribution vessel takes place in order to reduce the reactive oxygen in the interior of the distribution vessel largely.
- the adjustment and monitoring of the operating casting level height is preferably carried out via a distributor weight measurement or with an equivalent measuring method.
- the Railbadwigsburg can also be determined with other direct or indirect measurement methods, such. b. with floats, optical observation of the bath mirror surface, ultrasonic distance measurement, eddy current measurement and similar measuring methods.
- the bath level height in the distribution vessel continuously decreases during the melt vessel change, whereby a minimum bath level height must not be fallen below, which depends very substantially on the shape of the distribution vessel and therefore can not generally be determined.
- Excessive lowering of the bath level especially in the recovery phase of the melt supply, in particular at maximum filling rate, leads to an increased introduction of foreign particles into the metal melts, which spreads in the entire distribution vessel.
- the molten metal contained in the distribution vessel is divided by a partition plate into two subsets, wherein a first portion of molten metal from the melt vessel is supplied and from a second subset molten metal in the Continuous casting mold is derived and a transfer of molten metal from the first subset to the second subset is carried out continuously, wherein the inflow rate to the first subset in the distribution vessel is greater than the outflow rate from the second subset, wherein 70% to 100%, preferably 70% to 99 %, in particular during 70% to 95% of the time from the
- the positive effects of the spatial separation in the distribution vessel are further enhanced when the supply of molten metal within the last 5% to 30% of the time from the resumption of the supply of molten metal in the distribution vessel until reaching the quasi-stationary RadioLiterobe
- the second subset in Distributed vessel with a reduced compared to the inflow rate in the upstream period inflow rate takes place.
- the filling time can be shortened until reaching the quasi-stationary Radiodetassisted Device (PLA), PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, PLA, a contrast reduced filling rate.
- the transfer of molten metal from the first subset to the second subset, thus from one region of the distribution vessel into the other part of the distribution vessel, takes place through one or more openings in the compartment plate.
- the transfer of the molten metal from the first subset to the second subset can take place through a free space of the compartment plate and the bottom of the distributor vessel. In this case, the compartment plate is not introduced to the bottom of the distribution vessel.
- the partition plate as a firmly anchored component of the distribution vessel and to provide at least one permanent flow channel near the bottom of the distribution vessel, which lies in all operating phases entirely below the bath surface of the molten metal.
- the quasi-stationary casting process begins when the quasi-stationary operating bath level is reached in the second subset of the molten metal in the second region of the distributor vessel. Upon reaching this quasi-stationary RadioLiterobe Noticeariflop in the second subset of the molten metal in the distribution vessel, the supply of molten metal in the distribution vessel is controlled in terms of quantity depending on the removal of the molten metal from the distribution vessel. This control is based on a measurement of the current bath level or the current distributor weight.
- Fig. 1 shows a schematic representation of a Zweiwalzeng tellmaschine as a way to carry out the method according to the invention with the essential structural components for feeding the molten metal in the two oppositely rotating casting rolls 1, 2 and the end faces of the casting rollers can be pressed side plates 3 continuous casting mold 4.
- the molten metal is from a melt vessel 5, which is usually formed by a replaceable supported on fork arms 6 a ladle turret ladle, passed through a shadow tube 7 in a distribution vessel 8.
- the shade tube 7 is associated with a slide closure 9 as a control element for the flow rate or filling rate. From the distribution vessel 8, the molten metal flows through a submersible pouring tube 10 into the mold cavity 11 of the continuous casting mold 4.
- the submersible pouring tube 10 is also associated with a slide closure 12 for controlling the quantity of melt to be supplied to the continuous casting mold 4.
- the closure members can also be formed by plugs which, projecting from above through the melt bath, controllably close the outflow opening of the respective melting vessel.
- the amount of intermediate metal melt stored in the distribution vessel 8 is kept as constant as possible during the continuous casting process. This is achieved by setting a predetermined pouring height h of the molten metal in the distribution vessel and keeping this level of pouring means as constant as possible by means of an inflow quantity control.
- a largely uniform G fauxwig thanks stays ensures a uniform melt transfer into the continuous casting mold. 4
- melt pool strand shells On the cooled cylinder jacket surfaces of the casting rolls 1, 2 are formed in the melt pool strand shells, which are rolled in the narrowest cross section between the casting rolls to a metal strand 13 of predetermined thickness and width.
- the empty melt vessel is removed from the casting and brought by a provided, filled melt vessel with prepared for casting molten metal in the casting in casting position.
- the casting process in the continuous casting mold is continued with the residual melt quantity present in the distributor vessel, the operating bath level level sinking to a minimum bath level height h pool, min, but the shadow tube is still immersed in the melt bath.
- the filling of the distribution vessel is carried out according to a possible embodiment according to the in Fig. 2 illustrated filling curve course.
- the distribution vessel there is a residual amount of steel which corresponds to a bath level height h pool, min .
- the molten metal is passed in a first filling phase (time t 0 - t 1 ) with the greatest possible opening of the slide valve closure in the distribution vessel, ie the molten metal enters the distribution vessel with maximum filling rate ⁇ fill, max .
- the fill rate is substantially continuously withdrawn until the quasi-stationary Radio-badwigiere h pool, op is reached, wherein during 70% to 95% of the period from the resumption of the supply of molten metal in the Distribution vessel until reaching the quasi-stationary Operating pool height h pool, opt is the inflow rate in the tundish ner to twice the Abffussrate from the tundish is.
- the stationary filling rate ⁇ st is reached, which is characteristic for the stationary casting operation.
- Fig. 3 shows a further embodiment of a possible filling curve, wherein the molten metal in a first filling phase (time t 0 - t 1 ) with maximum filling rate ⁇ fill, max or approximately maximum filling rate (more than 80% of the maximum filling rate) and after reaching the time t 1 gradually reduced in several stages, wherein the reduction of the filling rate in the individual times t 1 to t 5 takes place so that a degressive approximation of the BadLite Too h pool to the Radiobadwig Little hp ool, op takes place.
- the stationary filling rate ⁇ st is reached, which is characteristic of the stationary casting operation.
- Fig. 4 shows the increase of the distributor weight m v over the filling time, starting from a distributor weight m 0 , which corresponds to the tare weight of the distributor vessel and the weight of the residual melt quantity remaining in the distributor vessel, up to the distributor weight m 5 , which is reached when the quasi-stationary operating bath level h pool is reached, op is achieved.
- This calming phase in the distribution vessel can be additionally reinforced by briefly interrupting the supply of melt after reaching the quasi-stationary operating bath level height.
- a supplementary task of an angle-down agent on the metal bath surface can take place, which is carried out with a semi-automatic or fully automatic loading device 15 (FIG. Fig. 1 ), whose outlet opening opens above the bath level in one or more areas of the distribution vessel with little surface turbulence.
- the fine-grained to dust-like covering is applied to the molten metal in a continuous trickle and should ensure complete coverage of the metal bath in the distribution vessel.
- the distribution vessel 8 is covered with a distributor cover 16, with which the interior of the distribution vessel is shielded from the atmosphere. This also gives the possibility to perform an inerting of the interior even before the supply of molten metal, in particular during the initial filling of the distribution vessel.
- the quasi-stationary Radiodetectik altar arrived Upon reaching the quasi-stationary Radiodebadadorsburg begins the re-introduction of the continuous casting operation.
- the amount of the molten metal supplied to the distributor vessel is set or regulated as a function of the amount of melt introduced from the distributor vessel into the continuous casting mold. Deviations of the bath level from the desired quasi-stationary operating bath level are detected by a distributor weight measurement. Characterized a characteristic of the Badadornch measured variable is continuously determined and used in an inflow control loop to control the inflowing molten metal as a control or controlled variable.
- the distribution vessel 8 is supported via measuring cells 17 on a support framework 18, for example a movable distribution vehicle ( Fig.1 ).
- Fig. 5a the Sequenzg foolvon invention is shown using the example of a steel strip casting plant, over a time axis, the course of characteristic characteristics, such as the distribution weight W tundish , the fill rate in the distributor ⁇ ladle , and the filling rate in the mold ⁇ mold with a time lead, starting before the Carrying out the change of a melt vessel, and with a time lag after the restart of the stationary casting operation is illustrated. Measures are taken even before the beginning of the vessel change, which facilitate the bridging of the changeover time of about 2 minutes by increasing the available amount of melt in the distribution vessel.
- the resumption of the supply of melt takes place in the distribution vessel with a significantly reduced filling rate ⁇ ladle, start , which corresponds to 0.8 to 1.2 times the filling rate ⁇ load, opt corresponds to stationary casting operation.
- This reduced fill rate may conveniently be within a range of 0.5 to 2 times the fill rate ⁇ ladle, opt .
- the fill rate is kept approximately constant over a wide range of times for refilling the tundish.
- the fundamental advantage of this variant lies in the much lower inflow velocity of the molten metal into the intermediate vessel and thus significantly less surface turbulence on the metal bath.
- the flow rate remains small enough to ensure a good rate of deposition of the non-metallic inclusions into the slag layer and to avoid the reintroduction of slag.
- the time required for the refilling of the distributor vessel is increased to up to 25 minutes with simultaneously reduced filling rate in the mold.
- a suitable filling rate curve can be chosen, which can be used between the in Fig. 5a and Fig. 5b illustrated embodiments lies.
- Fig. 6 a possibility is shown which is intended to largely exclude the entry of masking agent applied to the melt bath into the interior of the melt bath or in the vicinity of the outer wall of the shadow pipe.
- molten metal continuously flows out of the melt vessel 5 through the shadow tube 7, which dips vertically into the melt.
- the inflowing molten metal creates a suction effect along the shadow tube and any slag / covering agent collected in this area is drawn down into the molten metal.
- the cup-shaped, which surrounds the shadow tube at a radial distance from this and projects from above into the molten metal the formed slag layer 20 is kept away from the critical area near the shade tube.
- this cover can be rendered inert via the protective gas line 22.
- this cover extends so far into the melt bath, that even at minimum Badadorproof Eck h min immersion of the shadow tube is guaranteed.
- the current level of the bath level during the change of the melt vessel does not fall below the value h min , ie it is imperative that the lower edge of the cover 21 always immersed in the melt bath.
- the shadow tube 7 is located in the outflow direction of the molten metal, a flow-damping element 23 (turbo stop) firmly anchored in the distribution vessel, whereby the liquid metal jet flowing into the distribution vessel is strongly decelerated.
- the described sequence casting method has been found to be particularly successful in connection with a distribution vessel, which in the WO 03/051560 is described and has a geometry that promotes the deposition of extraneous particles especially.
- a vertically movable compartment plate 24 is shown in two operating positions in communication with the distribution vessel 8.
- a functional separation in the distribution vessel is to be achieved.
- Fig. 7a shows the operating state in the distribution vessel immediately before re-casting with a new melt vessel.
- the molten metal still available in the distributor vessel is covered with a covering agent and flows off at a speed corresponding to the reduced casting speed.
- the compartment plate is still in a raised position and is lowered into the distribution vessel to make it, as in Fig. 7b shown to divide into two areas.
- a first region 25 is associated with the supply of melt
- a second region 26 is associated with the discharge of the melt in the continuous casting mold.
- the first area 25 there is a substantial calming of the melt bath and the deposition of a Most of the foreign particles to the slag layer in the first area.
- the second region 26 the deposition of residues of foreign particles still contained in the molten metal takes place in the slag layer covering the metal bath.
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Abstract
Description
Die Erfindung betrifft ein Sequenzgießverfahren zur kontinuierlichen Herstellung eines gegossenen Metallstranges hoher Reinheit aus einer Metallschmelze, vorzugsweise einer Stahlschmelze, wobei die Metallschmelze von einem Schmelzengefäß geregelt einem Verteilergefäß zugeführt und von diesem Verteilergefäß geregelt in eine Stranggießkokille abgeführt wird und wobei die Zufuhr von Metallschmelze in das Verteilergefäß während dem Wechsel des Schmelzengefäßes unterbrochen wird, während die Zufuhr der Metallschmelze in die Stranggießkokille weitergeführt wird.The invention relates to a Sequenzgießverfahren for continuously producing a cast high-purity metal strand from a molten metal, preferably a molten steel, wherein the molten metal from a melt vessel regulated supplied to a distribution vessel and controlled by this distribution vessel is discharged into a continuous casting mold and wherein the supply of molten metal in the distribution vessel is interrupted during the change of the melt vessel, while the supply of the molten metal is continued in the continuous casting mold.
Unter Sequenzgießverfahren ist ein Gießverfahren zu verstehen, bei welchem mehrere Metallchargen, die an die Gießanlage in mehreren Schmelzengefäßen angeliefert werden, ohne Unterbrechung des Gießprozesses kontinuierlich zu einem einzigen Metallstrang vergossen werden. Hierbei ist es notwendig, das Schmelzengefäß nach dessen Entleerung gegen ein weiteres gefülltes Schmelzengefäß in möglichst kurzer Zeit auszutauschen. Zwangsweise kommt es zu einer Unterbrechung des Schmelzenzuflusses in das Verteilergefäß und es ist notwendig die Restmenge im Verteilergefäß so zu bemessen, dass eine ausreichende Menge an Restmetallschmelze zur Überbrückung der benötigten Wechselzeit im Verteilergefäß vorrätig ist, bis aus dem in Gießposition gebrachten weiteren Schmelzengefäß wieder Metallschmelze in das Verteilergefäß zufließen kann. Um den kontinuierlichen Gießprozess über die Wechselzeit aufrecht erhalten zu können, ist es üblich, die Gießgeschwindigkeit der Gießanlage während der Wechselzeit zu reduzieren. Mit einem Pfannendrehturm kann die Wechselzeit sehr kurz gehalten werden.Sequence casting refers to a casting process in which multiple lots of metal delivered to the caster in multiple melt vessels are continuously potted into a single metal strand without interrupting the casting process. It is necessary to replace the melt vessel after emptying it against another filled melt vessel in the shortest possible time. Forcibly, there is an interruption of the melt flow into the distribution vessel and it is necessary to measure the remaining amount in the distribution vessel so that a sufficient amount of residual metal melt to bridge the required change time in the distribution vessel is in stock, from the placed in the casting position further melt vessel again molten metal in the distribution vessel can flow. In order to maintain the continuous casting process over the change time, it is common to reduce the casting speed of the casting machine during the changeover time. With a ladle turret, the changeover time can be kept very short.
Die Stranggießanlage selbst kann mit einer Kokille beliebiger Bauart, wie beispielsweise einer oder mehreren oszillierenden Platten- oder Rohrkokillen, mit Raupenkokillen, mit Kokillen mit umlaufenden Bändern oder Kokillen die von rotierenden Gießwalzen mit seitlichen Dämmwänden gebildet werden, ausgestattet sein. Auch das Querschnittsformat des zu gießenden Metallstranges kann beliebig sein, jedoch ergeben sich speziell bei der Herstellung von dünnen Metallbändern mit Banddicken unter 6,0 mm und Bandbreiten über 800 mm besondere Anforderungen an die Startphase bzw. Restart-Phase des Gießprozesses nach einem Pfannenwechsel, da insbesondere wegen des relativ kleinen Schmelzenpools und der praktisch unveränderlichen metallurgischen Länge bis zum kissing point in einer Zweiwalzengießanlage, sowie der schnellen Durcherstarrung eines dünnen Metallstranges eine wesentliche Reduzierung der Gießgeschwindigkeit nicht möglich ist. Weiters ist zu berücksichtigen, dass bei der Wiederaufnahme der Schmelzenzufuhr in das Verteilergefäß eine verstärkte Badbewegung in der bereits mit Abdeckmittel bedeckten Restmetallschmelze entsteht und durch die verstärkte Wellenbildung an der Badoberfläche ein Eintrag von Abdeckmittel in das Metallbad verstärkt auftritt. Weiters wird beim Öffnen des Pfannenschiebers Füllsand in das Verteilergefäß, eingetragen, der eine gewisse Zeit und ein beruhigtes Metallbad benötigt, um an die Badoberfläche aufschwimmen zu können. Die Erfindung bezieht sich insbesondere auf das Gießen eines Metallbandes mit einer Zweiwalzengießanlage nach dem vertikalen Zweiwalzengießverfahren.The continuous casting itself can be equipped with a mold of any type, such as one or more oscillating plate or tube molds, with caterpillars, with molds with circumferential bands or molds are formed by rotating casting rolls with lateral Dämmwänden. The cross-sectional format of the metal strand to be cast can be arbitrary, but arise especially in the production of thin metal strips with strip thicknesses below 6.0 mm and bandwidths over 800 mm special requirements for the start phase or restart phase of the casting process after a ladle change, because in particular because of the relatively small melt pool and the virtually invariable metallurgical length to the kissing point in a two-roll casting, as well as the rapid solidification of a thin metal strand a significant reduction of Casting speed is not possible. Furthermore, it should be taken into account that, when the supply of melt in the distribution vessel resumes, there is an increased bath movement in the residual metal melt already covered with covering agent, and an increased coverage of the bath surface causes an entry of covering agent into the metal bath. Furthermore, filling sand is introduced into the distribution vessel when the ladle slide is opened, which requires a certain amount of time and a calmed metal bath in order to be able to float to the bath surface. More particularly, the invention relates to the casting of a metal strip with a two-roll caster according to the vertical two-roll casting process.
Bei der Herstellung eines gegossenen Metallstranges hoher Reinheit mit einer beliebigen Stranggießanlage wird das flüssige Metall üblicherweise von einer Gießpfanne über zumindest ein Zwischengefäß oder Verteilergefäß einer gekühlten Kokille zugeführt, in der der Erstarrungsprozess der Metallschmelze zu einem Metallstrang zumindest eingeleitet wird. Die Überleitung der Metallschmelze von der Gießpfanne in das Verteilergefäß und aus diesem weiter in die Kokille erfolgt vorwiegend durch Tauchrohre oder Schattenrohre, die im stationären Gießbetrieb in den Schmelzenpool des jeweils nachgeordneten Gefäßes eintauchen und so eine möglichst beruhigte und gleichmäßige Strömung und Weiterleitung der Metallschmelze bis in die Kokille ermöglichen. Üblicherweise ist die in der Gießpfanne, dem Zwischengefäß und gegebenenfalls in der Kokille angesammelte Metallschmelze von einer Schlackenschicht bedeckt, durch die die Metallbadoberfläche vor Oxidation geschützt wird. Die grundsätzliche Anordnung der Schmelzenaufnahmegefäße bei einer mehrsträngigen Stranggießanlage für Stahl ist beispielsweise aus der
Generell ist bekannt, dass die Qualität des gegossenen Stranges herabgesetzt ist, wenn starke Badspiegelschwankungen auftreten, wie sie in der Startphase des Gießprozesses bei der Erstfüllung des Verteilergefäßes unvermeidbar sind, oder wie sie während der Durchführung des Pfannenwechsel beim Sequenzgießen auftreten, bei dem üblicherweise mit der im Verteiler vorrätigen Metallschmelze die Wechselzeit der Pfanne überbrückt wird und daher mit kontinuierlich abnehmender Badspiegelhöhe gegossen wird. Die Stabilität der Schmelzenströmung im Verteilergefäß ist dadurch stark beeinträchtigt und die Metallschmelze ist unerwünschtem Schlackeneintrag ausgesetzt.In general, it is known that the quality of the cast strand is reduced when strong Badspiegelschwankungen occur, as they are unavoidable in the startup of the casting process in the first filling of the tundish, or as they occur during the performance of Pfannenwechsel the sequence casting, which usually with the in the distributor vorrätigen molten metal, the change time of the pan is bridged and is therefore poured with continuously decreasing Badspiegelhöhe. The stability of the melt flow in the distribution vessel is thereby greatly impaired and the molten metal is exposed to undesirable slag entry.
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Aufgabe der Erfindung ist es daher diese Nachteile und Schwierigkeiten des bekannten Standes der Technik zu vermeiden und ein Sequenzgießverfahren der eingangs beschriebenen Art vorzuschlagen, mit dem auch während des Schmelzengefäßwechsels ein erhöhter Eintrag von Fremdpartikeln in die Metallschmelze und somit in der Stranggießkokille ein analoger bzw. erhöhter Eintrag von Fremdpartikel ins Erstarrungsprodukt minimiert und unmittelbar im Zusammenhang mit der Wiederaufnahme der quasi-stationären Gießphase ein Metallstrang hoher Reinheit gegossen werden kann, bei dem weiters diese Überbrückungsphase im kontinuierlichen Gießprozess möglichst kurz gehalten werden kann und bei dem zumindest Auswirkungen aus nicht-stationären Gießphasen, wie dem Schmelzengefäßwechsel, möglichst schnell abklingen.The object of the invention is therefore to avoid these disadvantages and difficulties of the known prior art and to propose a Sequenzgießverfahren of the type described above, with an increased entry of foreign particles in the molten metal and thus in the continuous casting mold an analogous or elevated during the Schmelzengefäßwechsel Minimized entry of foreign particles into the solidification product and directly in connection with the resumption of the quasi-stationary casting phase, a metal strand of high purity can be poured, where further this bridging phase in the continuous casting process can be kept as short as possible and at least the effects of non-stationary casting phases, as the melt vessel change, as soon as possible decay.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, dass während einer Zeitspanne von der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß bis zum Erreichen einer quasi-stationären Betriebsbadspiegelhöhe im Verteilergefäß die Zuflussrate in das Verteilergefäß größer ist als die Abflussrate aus dem Verteilergefäß und wobei während 70% bis 100%, vorzugsweise während 70% bis 99%, insbesondere während 70% bis 95%, dieser Zeitspanne die Zuflussrate in das Verteilergefäß kleiner oder gleich dem Doppelten, vorzugsweise kleiner oder gleich dem 1,5-fachen, der Abflussrate aus dem Verteilergefäß beträgt.This object is achieved in that during a period of time from the resumption of the supply of molten metal in the distribution vessel until reaching a quasi-stationary Betriebsbadspiegelhöhe in the distribution vessel, the inflow rate in the distribution vessel is greater than the outflow rate from the distribution vessel and wherein during 70% to 100%, preferably during 70% to 99%, especially during 70% to 95%, of this period, the inflow rate in the distribution vessel is less than or equal to twice, preferably less than or equal to 1.5 times, the outflow rate from the distribution vessel.
Die minimale Zuflussrate in das Verteilergefäß innerhalb dieser Zeitspanne hängt sehr wesentlich von der Reduktion der Gießgeschwindigkeit auf der Stranggießanlage während des Schmelzengefäßwechsels ab. Die Zuflussrate in das Verteilergefäß sollte während dieser Zeitspanne jedoch mindestens dem 0,5-fachen der maximalen Zuflussrate bei stationärem Gießbetrieb entsprechen.The minimum inflow rate into the tundish within this period of time is very much dependent on the reduction in casting speed on the caster during the melt vessel change. However, the inflow rate into the tundish during this period should be at least 0.5 times the maximum steady state inflow rate.
Der Begriff "Verteilergefäß" ist hier nicht nur auf das Aufnahmegefäß für Metallschmelze beschränkt, durch welches die Überleitung oder Verteilung von Metallschmelze in eine Kokille ermöglicht wird, somit einer Kokille direkt vorgeordnet ist, sondern kann alle Schmelzengefäße zwischen der Gießpfanne und der Kokille umfassen.The term "distribution vessel" is here not limited to the receiving vessel for molten metal, through which the transfer or distribution of molten metal is made possible in a mold, thus directly preceded by a mold, but may include all melt vessels between the ladle and the mold.
Eine weitere Verbesserung in der Qualität des gegossenen Stranges ab Wiederaufnahme des Gießprozesses wird erreicht, wenn die Zufuhr von Metallschmelze innerhalb der letzten 5% bis 30% der Zeitspanne von der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe mit einer gegenüber der Zuflussrate in der vorgelagerten Zeitspanne reduzierten Zuflussrate erfolgt.A further improvement in the quality of the cast strand from the resumption of the casting process is achieved when the supply of molten metal within the last 5% to 30% of the period from the resumption of the supply of molten metal in the distribution vessel until reaching the quasi-stationary Betriebsbadspiegelhöhe a reduced inflow rate compared to the inflow rate in the upstream period takes place.
Eine Verkürzung der Wiederaufnahmephase des Gießprozesses und ein maximal gesichertes Öffnen des Schmelzenbehälters wird ohne Beeinträchtigung der Qualität des Gussproduktes erreicht, wenn die Zufuhr von Metallschmelze unmittelbar mit Wiederaufnahme der Schmelzenzufuhr in das Verteilergefäß während 0,1% bis 30%, vorzugsweise während 3% bis 15%, der Zeitspanne bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe im Verteilergefäß mit maximaler Zuflussrate erfolgt und die Zufuhr von Metallschmelze anschließend bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe mit einer demgegenüber reduzierten Füllrate erfolgt.A shortening of the resumption phase of the casting process and a maximum secure opening of the melt container is achieved without affecting the quality of the cast product, when the supply of molten metal immediately with resumption of the supply of melt into the tundish during 0.1% to 30%, preferably during 3% to 15 %, the time taken to reach the quasi-stationary Betriebsbadspiegelhöhe in the distribution vessel with maximum inflow rate and the supply of molten metal then takes place until reaching the quasi-stationary Betriebsbadspiegelhöhe with a contrast reduced filling rate.
Unter "maximaler Füllrate" ist zu verstehen, dass die Zufuhr der Metallschmelze in das Verteilergefäß bei maximaler Öffnung des Pfannenschiebers, das heißt mit der maximal möglichen Füllrate, erfolgt. Damit wird auch ein Zufrieren der Pfannenschieberöffnung in der Angießphase bzw. eine markante Verengung der Durchflussöffnung und damit eine unerwünschte Reduzierung der Durchflussmenge vermieden.The term "maximum filling rate" is to be understood as meaning that the supply of molten metal into the distributor vessel takes place at maximum opening of the ladle slide, that is to say at the maximum possible filling rate. This also prevents freezing of the ladle slide opening in the Angießphase or a significant narrowing of the flow opening and thus an undesirable reduction in the flow rate is avoided.
Die reduzierte Füllrate stellt über die Restfüllzeit bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe nicht notwendigerweise einen konstanten Wert dar, sondern folgt eher einem kontinuierlich oder schrittweise abnehmenden zeitlich en Verlauf, wodurch sich die Strömungsverhältnisse im Verteilergefäß bereits während der Füllzeit kontinuierlich beruhigen.The reduced filling rate does not necessarily represent a constant value over the remaining filling time until the quasi-stationary operating bath level height is reached, but rather follows a continuous or stepwise decreasing time course, as a result of which the flow conditions in the distributor vessel steadily settle during the filling time.
Zur Beruhigung der Metallschmelze im Verteilergefäß kann es zweckmäßig sein, wenn die Zufuhr von Metallschmelze in das Verteilergefäß mit Erreichen der quasi-stationären Betriebsbadspiegelhöhe für eine bestimmte Zeitspanne sogar unterbrochen wird. Das Schließen des Pfannenschiebers nach Erreichen der quasi-stationären Betriebsbadspiegelhöhe hat den Vorteil, dass vorhandene Fremdeinschlüsse, insbesondere nichtmetallische Einschlüsse, am Badspiegel schnell aufschwimmen und in die Abdeckschlacke abgeschieden werden können. Die kurzzeitige Unterbrechung der Schmelzenzufuhr stellt eine gute Möglichkeit dar, die Qualität des gegossenen Produktes zu erhöhen, wenn gleichzeitig sichergestellt ist, dass das Öffnen des Pfannenschiebers nach dieser Beruhigungs- und Abscheidephase sicher gewährleistet ist. Die Zeitspanne der Unterbrechung der Schmelzenzufuhr beträgt zwischen 1 sec und 2 min, vorzugsweise zwischen 10 sec und 70 sec, da der Badspiegel zufolge des in die Stranggießkokille abfließenden Metalls sofort wieder zu sinken beginnt.To soothe the molten metal in the distribution vessel, it may be expedient if the supply of molten metal is even interrupted in the distribution vessel with reaching the quasi-stationary Betriebsbadspiegelhöhe for a certain period of time. The closing of the pan slide after reaching the quasi-stationary Betriebsbadspiegelhöhe has the advantage that existing foreign inclusions, especially non-metallic inclusions, quickly float at the bath level and can be deposited in the cover slag. The short-term interruption of the supply of melt is a good way to increase the quality of the molded product, while at the same time ensuring that the opening of the pan valve is guaranteed after this calming and deposition phase. The period of interruption of the supply of melt is between 1 second and 2 minutes, preferably between 10 seconds and 70 seconds, since the bath level begins to drop again as a result of the metal flowing out of the continuous casting mold.
Zur Vermeidung von Reoxidation an der Metallbadoberfläche wird üblicherweise bereits bei Beginn der ersten Gießsequenz ein Abdeckmittel auf das Schmelzenbad aufgebracht. Dieses Abdeckmittel bleibt über alle Gießsequenzen im Verteilergefäß erhalten. Damit das Abdeckmittel im Nahbereich des in die Metallschmelze eintauchenden Schattenrohres nicht - auch nur partiell - entlang der Außenwand des Schattenrohres in die Metallschmelze eingezogen wird, ist es zweckmäßig, wenn ein das Schattenrohr unmittelbar umgebender Bereich der freien Badoberfläche im Verteilergefäß von der Abdeckung mit einem Abdeckmittel zumindest während des quasi-stationären Betriebes, vorzugsweise ständig, freigehalten bzw. abgeschirmt wird. Dies erfolgt vorzugsweise du rch Abschirmmittel, die von Wandelementen gebildet sind, die entweder von oben in das Schmelzenbad eintauchen oder von unten aus dem Schmelzenbad herausragen und das Schattenrohr mit Abstand umgeben. Damit wird gezielt ein "hot spot" rund um das Schattenrohr erzeugt und es ist zweckmäßig, wenn die Wandelemente eine geschlossene Kammer bilden, in die das Schattenrohr integriert und die in der Kammer eingeschlossene Atmosphäre inertisiert ist.To avoid reoxidation on the metal bath surface, a covering agent is usually applied to the melt bath already at the beginning of the first casting sequence. This covering agent is retained over all casting sequences in the distribution vessel. Thus, the covering in the vicinity of the dipping into the molten metal shadow tube is not - even partially - along the outer wall of the shadow tube is drawn into the molten metal, it is useful if a shadow tube immediately surrounding area of the free bath surface in the distribution vessel of the cover with a covering at least during quasi-stationary operation, preferably constantly, kept free or shielded. This is preferably carried out by shielding means which are formed by wall elements which either dip from above into the melt bath or protrude from below from the melt bath and surround the shade tube at a distance. This purposefully creates a "hot spot" around the shadow tube and it is expedient if the wall elements form a closed chamber in which the shadow tube is integrated and the atmosphere enclosed in the chamber is rendered inert.
Wichtig ist, dass die Abschirmmittel soweit in das Schmelzenbad eintauchen, dass diese auch während des Pfannenwechsels bei minimaler Badspiegelhöhe knapp vor der Wiederaufnahme der Schmelzenzufuhr noch in das Verteilergefäß eintauchen. Damit wird die schlackenfreie Zone um das Schattenrohr auch in dieser Betriebsphase aufrechterhalten und die Zufuhr von Metallschmelze mit geringen Turbulenzen im Metallbad unterhalb der Badoberfläche sichergestellt.It is important that the shielding so far immersed in the melt bath that they even during the pan change at minimum Badspiegeltauchen just before resuming the supply of melt still dive into the distribution vessel. Thus, the slag-free zone is maintained by the shadow tube in this phase of operation and the supply of molten metal with low turbulence in the metal bath below the bath surface ensured.
Sofern nach dem Erreichen der quasi-stationären Betriebsbadspiegelhöhe im Verteilergefäß die Zufuhr von Metallschmelze nochmals kurzzeitig unterbrochen wird, um die Badbewegung zusätzlich zu beruhigen und die Abscheiderate von Fremdpartikel zu steigern, wird nach der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß diese Zufuhr von Metallschmelze in das Verteilergefäß mengenmäßig in Abhängigkeit von der Abfuhr der Metallschmelze aus dem Verteilergefäß geregelt. Die Überleitung der Metallschmelze vom Verteilergefäß in die nachgeordnete Kokille beginnt zeitlich mit der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß. Mit der Regelung wird die quasi-stationäre Betriebsbadspiegelhöhe bzw. das dem entsprechende Verteilergewicht weitgehend auf einem konstanten Niveau gehalten.If, after reaching the quasi-stationary Betriebsbadspiegelhöhe in the distribution vessel, the supply of molten metal is briefly interrupted again to calm the bath movement in addition to increase the deposition rate of foreign particles, after the resumption of the supply of molten metal in the distribution vessel, this supply of molten metal in the distribution vessel regulated in quantity as a function of the removal of the molten metal from the distribution vessel. The transfer of the molten metal from the distribution vessel into the downstream mold begins in time with the resumption of the supply of molten metal into the distribution vessel. With the regulation, the quasi-stationary operating bath level or the corresponding distributor weight is largely maintained at a constant level.
Sofern nach dem Erreichen der quasi-stationären Betriebsbadspiegelhöhe keine Unterbrechung der Schmelzenzufuhr in das Verteilergefäß erfolgt, wird zumindest während 70% bis 100%, vorzugsweise während 70% bis 99%, insbesondere während 70% bis 95% der Zeitspanne von der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß bis zum Erreichen einer quasi-stationären Betriebsbadspiegelhöhe im Verteilergefäß und/oder ab dem Erreichen der quasi-stationären Gießspiegelhöhe die Zufuhr von Metallschmelze in das Verteilergefäß mengenmäßig in Abhängigkeit von der Abfuhr der Metallschmelze aus dem Verteilergefäß geregelt. Diese Regelung basiert auf einer Messung der aktuellen Badspiegelhöhe oder des aktuellen Verteilergewichtes.If, after reaching the quasi-stationary Betriebsbadspiegelhöhe no interruption of the supply of melt into the distribution vessel, at least during 70% to 100%, preferably 70% to 99%, especially 70% to 95% of the time from the resumption of the supply of Metal melt in the distribution vessel to reach a quasi-stationary Betriebsbadspiegelhöhe in the distribution vessel and / or from reaching the quasi-stationary Gießspiegelhöhe the supply of molten metal in the distribution vessel in terms of quantity depending on the removal of molten metal from the distribution vessel regulated. This control is based on a measurement of the current bath level or the current distributor weight.
Die Menge der dem Verteilergefäß zugeführten Metallschmelze und die Menge der aus dem Verteilergefäß abgeführten Metallschmelze beträgt beim Gießen eines Stahlbandes, bei einer Gießdicke von 1,0 - 5,0 mm und einer Gießbreite von 1,0 m bis 2,0 m, zwischen 0,5 t/min und 4,0 t/min, vorzugsweise zwischen 0,8 t/min und 2,0 t/min. Diese Angaben beziehen sich auf die Verwendung einer Zweiwalzengießmaschine mit dem angestrebten Gussprodukt entsprechender Auslegung.The amount of molten metal supplied to the tundish and the amount of molten metal discharged from the tundish is, when casting a steel strip, at a casting thickness of 1.0 - 5.0 mm and a casting width of 1.0 m to 2.0 m, between 0 , 5 t / min and 4.0 t / min, preferably between 0.8 t / min and 2.0 t / min. This information refers to the use of a two-roll casting machine with the desired cast product of appropriate design.
In Ausnahmefällen kann es notwendig sein, Abdeckmittel im Verteilergefäß zu ergänzen. Vorzugsweise erfolgt die Aufgabe des Abdeckmittels auf die Badoberfläche der Metallschmelze im Zwischengefäß in einem Oberflächenbereich mit geringer Oberflächenströmungsgeschwindigkeit, Welligkeit der Badoberfläche und Turbulenzintensität.In exceptional cases, it may be necessary to supplement the masking agent in the distribution vessel. Preferably, the capping agent is applied to the bath surface of the molten metal in the tundish in a surface area of low surface flow rate, waviness of the bath surface, and turbulence intensity.
Eine fallweise manuelle Aufgabe des Abdeckmittels erfordert eine ausreichende Zugänglichkeit des Verteilergefäßes für das Bedienungspersonal und bringt zusätzlich den Nachteil zusätzlicher Schlackeneinsch lüsse durch die plötzliche lokale Aufgabe einer größeren Menge des Abdeckmittels mit sich. Das Abdeckmittel wird daher in feinkörniger Form oder pulverförmig, vorzugsweise mit einer halb- oder vollautomatischen Aufgabeeinrichtung, aufgebracht.A case by case manual task of the cover requires sufficient accessibility of the distribution vessel for the operator and also brings the disadvantage of additional Schlackeneinsch flows through the sudden local task of a larger amount of the covering with it. The covering agent is therefore applied in fine-grained form or in powder form, preferably with a semi-automatic or fully automatic feeding device.
Der Innenraum des Verteilergefäßes ist durch einen Verteilerdeckel gegen die freie Atmosphäre abgeschirmt, wobei es zweckmäßig ist, dass während oder vor der Erstfüllphase eine Inertisierung des Verteilergefäßes erfolgt, um den reaktiven Sauerstoff im Inneren des Verteilergefäßes weitgehend zu reduzieren.The interior of the distribution vessel is shielded by a distributor cover against the free atmosphere, wherein it is expedient that during or before the Erstfüllphase an inerting of the distribution vessel takes place in order to reduce the reactive oxygen in the interior of the distribution vessel largely.
Die Einstellung und Überwachung der Betriebsgießspiegelhöhe erfolgt vorzugsweise über eine Verteiler-Gewichtsmessung oder mit einem äquivalenten Messverfahren. Die Betriebsbadspiegelhöhe kann auch mit anderen direkten oder indirekten Messverfahren ermittelt werden, wie z. b. mit Schwimmern, optischer Beobachtung der Badspiegeloberfläche, Ultraschall-Distanzmessung, Wirbelstrommessung und ähnlichen Messverfahren.The adjustment and monitoring of the operating casting level height is preferably carried out via a distributor weight measurement or with an equivalent measuring method. The Betriebsbadspiegelhöhe can also be determined with other direct or indirect measurement methods, such. b. with floats, optical observation of the bath mirror surface, ultrasonic distance measurement, eddy current measurement and similar measuring methods.
Beim Sequenzgießen nimmt die Badspiegelhöhe im Verteilergefäß während des Schmelzengefäßwechsels kontinuierlich ab, wobei eine Mindestbadspiegelhöhe nicht unterschritten werden darf, die sehr wesentlich von der Form des Verteilergefäßes abhängt und daher nicht generell bestimmbar ist. Ein zu weitgehendes Absinken des Badspiegels führt insbesondere in der Wiederaufnahmephase der Schmelzenzufuhr, insbesondere bei maximaler Füllrate, zu einem verstärkten Fremdpartikeleintrag in die Metallsch melze, die sich in das gesamte Verteilergefäß ausbreitet. Um diesen Effekt zu unterdrücken bzw. zumindest wesentlich zu dämpfen, ist es zweckmäßig, wenn zumindest in der Zeitspanne zwischen der Wiederaufnahme der Zufuhr der Metallschmelze in das Verteilergefäß und dem Erreichen der quasi-stationären Betriebsbadspiegelhöhe die im Verteilergefäß enthaltene Metallschmelze durch eine Abteilplatte in zwei Teilmengen geteilt wird, wobei einer ersten Teilmenge Metallschmelze aus dem Schmelzengefäß zugeführt wird und von einer zweiten Teilmenge Metallschmelze in die Stranggießkokille abgeleitet wird und eine Überleitung von Metallschmelze von der ersten Teilmenge zur zweiten Teilmenge kontinuierlich erfolgt, wobei die Zuflussrate zur ersten Teilmenge im Verteilergefäß größer ist als die Abflussrate aus der zweiten Teilmenge, wobei während 70% bis 100%, vorzugsweise während 70% bis 99%, insbesondere während 70% bis 95%, der Zeitspanne von der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe der zweiten Teilmenge im Verteilergefäß die Zuflussrate zur ersten Teilmenge kleiner oder gleich dem Doppelten der Abflussrate aus der zweiten Teilmenge ist. Durch die räumliche Abteilung des Verteilergefäßes werden demnach zwei Bereiche geschaffen, nämlich ein erster Bereich, in dem zeitweise große Turbulenzen auftreten können und auch im Wesentlichen dort abklingen und einem zweiten Bereich, der hiervon weitgehend abgeschottet bleibt.During the sequence casting, the bath level height in the distribution vessel continuously decreases during the melt vessel change, whereby a minimum bath level height must not be fallen below, which depends very substantially on the shape of the distribution vessel and therefore can not generally be determined. Excessive lowering of the bath level, especially in the recovery phase of the melt supply, in particular at maximum filling rate, leads to an increased introduction of foreign particles into the metal melts, which spreads in the entire distribution vessel. In order to suppress this effect or to at least substantially attenuate it, it is expedient if at least in the period between the resumption of the supply of molten metal in the distribution vessel and the quasi-stationary Betriebsbadspiegelhöhe the molten metal contained in the distribution vessel is divided by a partition plate into two subsets, wherein a first portion of molten metal from the melt vessel is supplied and from a second subset molten metal in the Continuous casting mold is derived and a transfer of molten metal from the first subset to the second subset is carried out continuously, wherein the inflow rate to the first subset in the distribution vessel is greater than the outflow rate from the second subset, wherein 70% to 100%, preferably 70% to 99 %, in particular during 70% to 95% of the time from the resumption of the supply of molten metal in the distribution vessel until reaching the quasi-stationary Betriebsbadspiegelhöhe the second subset in the distribution vessel, the inflow rate to the first subset kl is equal to or twice the outflow rate from the second subset. Accordingly, two regions are created by the spatial division of the distribution vessel, namely a first region in which large turbulences can occur at times and also decay substantially there and a second region which remains largely sealed off from them.
Die positiven Effekte aus der räumlichen Trennung im Verteilergefäß werden zusätzlich verstärkt, wenn die Zufuhr von Metallschmelze innerhalb der letzten 5% bis 30% der Zeitspanne von der Wiederaufnahme der Zufuhr von Metallschmelze in das Verteilergefäß bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe der zweiten Teilmenge im Verteilergefäß mit einer gegenüber der Zuflussrate in der vorgelagerten Zeitspanne reduzierten Zuflussrate erfolgt.The positive effects of the spatial separation in the distribution vessel are further enhanced when the supply of molten metal within the last 5% to 30% of the time from the resumption of the supply of molten metal in the distribution vessel until reaching the quasi-stationary Betriebsbadspiegelhöhe the second subset in Distributed vessel with a reduced compared to the inflow rate in the upstream period inflow rate takes place.
Hierbei kann die Füllzeit bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe verkürzt werden, wenn die Zufuhr von Metallschmelze unmittelbar mit Wiederaufnahme der Schmelzenzufuhr in das Verteilergefäß während 0,1% bis 30%, vorzugsweise während 3% bis 15%, der Zeitspanne bis zum Erreichen der quasi-stationären Betriebsbadspiegelhöhe der zweiten Teilmenge im Verteilergefäß mit im Wesentlichen maximaler Zuflussrate erfolgt und anschließend bis zum Erreichen der Betriebsbadspiegelhöhe der zweiten Teilmenge im Verteilergefäß die Zufuhr von Metallschmelze mit einer demgegenüber reduzierten Füllrate erfolgt.Here, the filling time can be shortened until reaching the quasi-stationary Betriebsbadspiegelhöhe when the supply of molten metal immediately with resumption of the supply of melt into the tundish during 0.1% to 30%, preferably from 3% to 15%, the time to reach the quasi-stationary Betriebsbadspiegelhöhe the second subset in the distribution vessel with substantially maximum inflow rate is carried out and then until reaching the Betriebsbadspiegelhöhe the second subset in the distribution vessel, the supply of molten metal with a contrast reduced filling rate.
Die Überleitung von Metallschmelze von der ersten Teilmenge zur zweiten Teilmenge, damit von einem Bereich des Verteilergefäßes in den anderen Teil des Verteilergefäßes, erfolgt durch eine oder mehrere Öffnungen in der Abteilplatte. Vorzugsweise kann die Überleitung der Metallschmelze von der ersten Teilmenge zur zweiten Teilmenge durch einen Freiraum der Abteilplatte und dem Boden des Verteilergefäßes erfolgen. In diesem Fall wird die Abteilplatte nicht bis zum Boden des Verteilergefäßes eingebracht.The transfer of molten metal from the first subset to the second subset, thus from one region of the distribution vessel into the other part of the distribution vessel, takes place through one or more openings in the compartment plate. Preferably, the transfer of the molten metal from the first subset to the second subset can take place through a free space of the compartment plate and the bottom of the distributor vessel. In this case, the compartment plate is not introduced to the bottom of the distribution vessel.
Es ist allerdings auch möglich, die Abteilplatte als fest verankerten Bauteil des Verteilergefäßes auszubilden und mindestens einen permanenten Strömungskanal in Bodennähe des Verteilergefäßes vorzusehen, der in allen Betriebsphasen zur Gänze unter der Badoberfläche der Metallschmelze liegt.However, it is also possible to form the partition plate as a firmly anchored component of the distribution vessel and to provide at least one permanent flow channel near the bottom of the distribution vessel, which lies in all operating phases entirely below the bath surface of the molten metal.
Der quasi-stationäre Gießprozess beginnt mit Erreichen der quasi-stationären Betriebsbadspiegelhöhe bei der zweiten Teilmenge der Metallschmelze im zweiten Bereich des Verteilergefäßes. Mit Erreichen dieser quasi-stationären Betriebsbadspiegelhöhe bei der zweiten Teilmenge der Metallschmelze im Verteilergefäß wird die Zufuhr von Metallschmelze in das Verteilergefäß mengenmäßig in Abhängigkeit von der Abfuhr der Metallschmelze aus dem Verteilergefäß geregelt. Diese Regelung basiert auf einer Messung der aktuellen Badspiegelhöhe oder des aktuellen Verteilergewichtes.The quasi-stationary casting process begins when the quasi-stationary operating bath level is reached in the second subset of the molten metal in the second region of the distributor vessel. Upon reaching this quasi-stationary Betriebsbadspiegelhöhe in the second subset of the molten metal in the distribution vessel, the supply of molten metal in the distribution vessel is controlled in terms of quantity depending on the removal of the molten metal from the distribution vessel. This control is based on a measurement of the current bath level or the current distributor weight.
Weitere Vorteile und Merkmale der vorliegenden Erfindung ergeben sich aus der nachfolgenden Beschreibung nicht einschränkender Ausführungsbeispiele, wobei auf die beiliegenden Figuren Bezug genommen wird, die folgendes zeigen:
- Fig. 1
- eine schematische Darstellung einer Zweiwalzengießanlage mit einem Schmelzengefäß und einem Verteilergefäß zur Durchführung des erfindungsgemäßen Verfahrens,
- Fig. 2
- den Verlauf einer Anfahrkurve für das Wiederauffüllen des Verteilergefäßes (Füllrate) nach dem erfindungsgemäßen Verfahren in einer ersten Ausführungsform,
- Fig. 3
- den Verlauf einer Anfahrkurve für das Wiederauffüllen des Verteilergefäßes (Füllrate) nach dem erfindungsgemäßen Verfahren in einer zweiten Ausführungsform,
- Fig. 4
- den zeitlichen Verlauf des Verteilergewichtes während des Wiederauffüllens des Verteilergefäßes,
- Fig. 5a
- den Verlauf relevanter Verfahrenskenngrößen während des Wechsels eines Schmelzengefäßes nach einer dritten Ausführungsform der Erfindung,
- Fig. 5b
- den Verlauf relevanter Verfahrenskenngrößen während des Wechsels eines Schmelzengefäßes nach einer vierten Ausführungsform der Erfindung
- Fig. 6
- ein Schattenrohr mit Abschirmung gegen Kontakt mit Schlacke,
- Fig. 7a
- ein Verteilergefäß mit einer Abteilplatte in einer ersten ausgefahrenen Betriebsposition,
- Fig. 7b
- ein Verteilergefäß mit einer Abteilplatte in einer zweiten eingefahrenen Betriebsposition.
- Fig. 1
- a schematic representation of a two-roll caster with a melt vessel and a distribution vessel for carrying out the method according to the invention,
- Fig. 2
- the course of a start-up curve for the refilling of the distribution vessel (filling rate) according to the inventive method in a first embodiment,
- Fig. 3
- the course of a start-up curve for the refilling of the distribution vessel (filling rate) according to the inventive method in a second embodiment,
- Fig. 4
- the time profile of the distributor weight during the refilling of the distributor vessel,
- Fig. 5a
- the course of relevant process parameters during the change of a melting vessel according to a third embodiment of the invention,
- Fig. 5b
- the course of relevant process parameters during the change of a melting vessel according to a fourth embodiment of the invention
- Fig. 6
- a shade tube with shielding against contact with slag,
- Fig. 7a
- a distribution vessel with a partition plate in a first extended operating position,
- Fig. 7b
- a distribution vessel with a partition plate in a second retracted operating position.
Die Menge der im Verteilergefäß 8 zwischengelagerten Metallschmelze wird während des kontinuierlichen Gießvorganges möglichst konstant gehalten. Dies wird erreicht, indem im Verteilergefäß eine vorbestimmte Gießspiegelhöhe h der Metallschmelze eingestellt wird und diese Gießspiegelhöhe durch eine Zuflussmengenregelung möglichst konstant gehalten wird. Eine weitgehend gleichmäßige Gießspiegelhöhe sichert eine gleichmäßige Schmelzenüberleitung in die Stranggießkokille 4.The amount of intermediate metal melt stored in the
An den gekühlten Zylindermantelflächen der Gießwalzen 1, 2 bilden sich im Schmelzenpool nicht dargestellte Strangschalen aus, die im engsten Querschnitt zwischen den Gießwalzen zu einem Metallstrang 13 vorbestimmter Dicke und Breite verwalzt werden.On the cooled cylinder jacket surfaces of the casting rolls 1, 2 are formed in the melt pool strand shells, which are rolled in the narrowest cross section between the casting rolls to a
Nach der Entleerung des Schmelzengefäßes 5, wobei die die Metallschmelze im Schmelzengefäß bedeckende Schlacke möglichst nicht abfließen soll, wird das leere Schmelzengefäß aus der Gießanlage entfernt und durch ein bereitgestelltes, gefülltes Schmelzengefäß mit für den Guss vorbereiteter Metallschmelze in der Gießanlage in Gießposition gebracht. Während der hierfür benötigten Zeitspanne von etwa 2 min wird der Gießvorgang in der Stranggießkokille mit der im Verteilergefäß befindlichen Restschmelzenmenge fortgesetzt, wobei die Betriebsbadspiegelhöhe auf eine Minimalbadspiegelhöhe h pool,min absinkt, bei der das Schattenrohr jedoch immer noch in das Schmelzenbad eintaucht. Damit wird bei Wiederaufnahme der Schmelzenzufuhr in das Verteilergefäß ein direktes Auftreffen der Metallschmelze auf die das Metallbad abdeckende Schlackenschicht und damit deren intensive Durchmischung vermieden.After emptying the
Der Füllvorgang des Verteilergefäßes erfolgt nach einer möglichen Ausführungsvariante gemäß dem in
Diese dargestellten Füllkurvenverläufe nach den
Diese Beruhigungsphase im Verteilergefäß kann zusätzlich verstärkt werden, indem nach dem Erreichen der quasi-stationären Betriebsbadspiegelhöhe die Schmelzenzufuhr kurzzeitig unterbrochen wird. Innerhalb dieser Zeitspanne oder zu einem beliebigen späteren Zeitpunkt kann bei Bedarf eine ergänzende Aufgabe eines Abd eckmittels auf die Metallbadoberfläche erfolgen, die mit einer halb- oder vollautomatischen Aufgabeeinrichtung 15 erfolgt (
Zusätzlich ist das Verteilergefäß 8 mit einem Verteilerdeckel 16 abgedeckt, mit dem der Innenraum des Verteilergefäßes gegenüber der Atmosphäre abgeschirmt wird. Damit wird auch die Möglichkeit gegeben, noch vor der Zufuhr von Metallschmelze, insbesondere bei der Erstfüllung des Verteilergefäßes, eine Inertisierung des Innenraumes durchzuführen.In addition, the
Mit Erreichen der quasi-stationären Betriebsbadspiegelhöhe beginnt die Wiedereinleitung des kontinuierlichen Gießbetriebes. Hierbei wird die Menge der dem Verteilergefäß zugeführten Metallschmelze in Abhängigkeit von der aus dem Verteilergefäß in die Stranggießkokille eingeleiteten Schmelzenmenge eingestellt bzw. geregelt. Abweichungen der Badspiegelhöhe von der gewünschten quasi-stationären Betriebsbadspiegelhöhe werden über eine Verteilergewichtsmessung erfasst. Dadurch wird kontinuierlich eine für die Badspiegelhöhe charakteristische Messgröße ermittelt und in einem Zuflussregelkreis zur Regelung der zufließenden Metallschmelzenmenge als Stell- oder Regelgröße herangezogen. Das Verteilergefäß 8 ist hierzu über Messzellen 17 auf einem Traggerüst 18, beispielsweise einem verfahrbaren Verteilerwagen, abgestützt (
In
Nach einer weiteren Ausführungsform, die in
In
Dem Schattenrohr 7 liegt in Ausströmrichtung der Metallschmelze ein strömungsdämpfendes Element 23 (Turbostop) im Verteilergefäß fest verankert gegenüber, wodurch der in das Verteilergefäß einströmende Flüssigmetallstrahl stark abgebremst wird.The
Das beschriebene Sequenzgießverfahren hat sich als besonders erfolgreich in Verbindung mit einem Verteilergefäß gezeigt, welches in der
In den
Claims (20)
- Sequence casting process for the continuous production of a high-purity cast metal strand from a metal melt, preferably a steel melt, the metal melt being fed in controlled fashion from a melt vessel (5) to a tundish (8) and being discharged in controlled fashion from this tundish into a continuous-casting mould (4), and the supply of metal melt into the tundish being interrupted during the change of melt vessel, whereas the supply of the metal melt into the continuous-casting mould is continued, characterized in that during a period of time from the resumption of the supply of metal melt into the tundish (8) until the point at which a quasi-steady operating bath level in the tundish is reached, the inflow rate into the tundish is greater than the outflow rate out of the tundish, and for 70% to 100%, preferably for 70% to 99%, in particular for 70% to 95%, of this period the inflow rate into the tundish is less than or equal to double, preferably less than or equal to 1.5 times, the outflow rate out of the tundish.
- Sequence casting process according to Claim 1, characterized in that the inflow rate into the tundish (8) corresponds to at least 0.5 times the maximum inflow rate during steady-state casting operation.
- Sequence casting process according to Claim 1 or 2, characterized in that the supply of metal melt within the last 5% to 30% of the period from the resumption of the supply of metal melt into the tundish (8) until the point at which the quasi-steady operating bath level is reached takes place at an inflow rate which is reduced compared to the inflow rate during the preceding period of time.
- Sequence casting process according to one of the preceding claims, characterized in that the supply of metal melt takes place at a maximum inflow rate immediately on resumption of the supply of melt into the tundish (8) for 0.1% to 30%, preferably for 3% to 15%, of the period until the point at which the quasi-steady operating bath level in the tundish is reached, and thereafter the supply of metal melt takes place at a filling rate which is reduced compared to the initial filling rate, until the point at which the quasi-steady operating bath level is reached.
- Sequence casting process according to one of the preceding Claims 3 and 4, characterized in that the reduced filling rate follows a time curve which decreases continuously or in steps.
- Sequence casting process according to one of the preceding Claims, characterized in that the supply of metal melt into the tundish (8) is interrupted for a period of time when the quasi-steady operating bath level is reached.
- Sequence casting process according to Claim 6, characterized in that the period of time for which the supply of melt is interrupted lasts between 1 sec and 2 min, preferably between 10 sec and 70 sec.
- Sequence casting process according to one of the preceding claims, characterized in that a region of the free bath surface in the tundish (8) which immediately surrounds a shroud (7) is kept free of coverage with a covering agent at least during the quasi-steady-state operation.
- Sequence casting process according to one of the preceding Claims 6 and 7, characterized in that after the resumption of the supply of metal melt into the tundish (8), this supply of metal melt into the tundish is controlled quantitatively as a function of the discharge of the metal melt from the tundish.
- Sequence casting process according to one of Claims 1 to 8, characterized in that the supply of metal melt into the tundish is controlled quantitatively as a function of the discharge of the metal melt from the tundish at least for 70% to 100%, preferably for 70% to 99%, in particular for 70% to 95%, of the period from the resumption of the supply of metal melt into the tundish (8) until the point at which a quasi-steady operating bath level is reached in the tundish (8) and/or from the point at which the quasi-steady operating bath level is reached.
- Sequence casting process according to one of the preceding claims, characterized in that the quantity of metal melt supplied to the tundish (8) and the quantity of metal melt discharged from the tundish during casting of a steel strip on a two-roller casting installation is between 0.5 t/min and 4.0 t/min, preferably between 0.8 t/min and 2.0 t/min.
- Sequence casting process according to one the preceding claims, characterized in that a covering agent is added onto the bath surface of the metal melt in the tundish (8) on demand, and this addition of a covering agent onto the bath surface of the metal melt takes place in a surface region with a low surface flow velocity, waviness of the bath surface or turbulence intensity.
- Sequence casting process according to Claim 12, characterized in that the covering agent is applied in fine-grain or powder form.
- Sequence casting process according to one of the preceding claims, characterized in that the quasi-steady operating bath level is set and monitored by means of a tundish weight measurement or by means of an equivalent measurement method.
- Sequence casting process according to one of the preceding claims, characterized in that at least during the period between the resumption of the supply of the metal melt into the tundish (8) and the point at which the quasi-steady operating bath level is reached, the metal melt contained in the tundish is divided by a divider plate (24) into two partial quantities, metal melt from the melt vessel being fed to a first partial quantity and metal melt being discharged from a second partial quantity into the continuous-casting mould (4), and metal melt being transferred continuously from the first partial quantity to the second partial quantity, the inflow rate to the first partial quantity in the tundish (8) being greater than the outflow rate from the second partial quantity, and the inflow rate to the first partial quantity being less than or equal to double the outflow rate from the second partial quantity for 70% to 100%, preferably for 70% to 99%, in particular for 70% to 95%, of the period from the resumption of the supply of metal melt into the tundish until the point at which the quasi-steady operating bath level of the second partial quantity in the tundish is reached.
- Sequence casting process according to Claim 15, characterized in that the supply of metal melt within the last 5% to 30% of the period from the resumption of the supply of metal melt into the tundish (8) until the point at which the quasi-steady operating bath level of the second partial quantity in the tundish is reached takes place at an inflow rate which is reduced compared to the inflow rate during the preceding period of time.
- Sequence casting process according to Claim 15 or 16, characterized in that the supply of metal melt takes place at a maximum inflow rate immediately on resumption of the supply of melt into the tundish (8) for 0.1% to 30%, preferably for 3% to 15%, of the period until the point at which the quasi-steady operating bath level of the second partial quantity in the tundish is reached, and thereafter the supply of metal melt takes place at a filling rate which is reduced compared to this maximum inflow rate until the point at which the operating bath level of the second partial quantity in the tundish is reached.
- Sequence casting process according to one of Claims 15 to 17, characterized in that metal melt is transferred from the first partial quantity to the second partial quantity through one or more openings in the divider plate (24).
- Sequence casting process according to one of Claims 15 to 17, characterized in that metal melt is transferred from the first partial quantity to the second partial quantity through a free space between the divider plate (24) and the base of the tundish (8).
- Sequence casting process according to one of Claims 15 to 19, characterized in that when the quasi-steady operating bath level of the second partial quantity of the metal melt in the tundish is reached, the supply of metal melt into the tundish is controlled quantitatively as a function of the discharge of the metal melt from the tundish (8).
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AT0192703A AT413084B (en) | 2003-12-02 | 2003-12-02 | SEQUENCING METHOD FOR PRODUCING A CAST METAL STRIP OF HIGH PURITY |
PCT/EP2004/012711 WO2005053877A2 (en) | 2003-12-02 | 2004-11-10 | Sequential casting method for the production of a high-purity cast metal billet |
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AUPO591697A0 (en) * | 1997-03-27 | 1997-04-24 | Bhp Steel (Jla) Pty Limited | Casting metal strip |
GB9713265D0 (en) * | 1997-06-25 | 1997-08-27 | Kvaerner Clecim Cont Casting | Improvements in and relating to casting |
DE19915268A1 (en) * | 1999-04-03 | 2000-10-05 | Sms Demag Ag | Process for casting a continuous caster |
JP2000326056A (en) * | 1999-05-21 | 2000-11-28 | Nippon Steel Corp | Method and device for controlling molten metal surface level in twin roll type continuous casting equipment |
AT411024B (en) | 2001-12-14 | 2003-09-25 | Voest Alpine Ind Anlagen | INTERMEDIATE VESSEL AND METHOD FOR PRODUCING A METAL STRAND OF HIGH PURITY |
-
2003
- 2003-12-02 AT AT0192703A patent/AT413084B/en not_active IP Right Cessation
-
2004
- 2004-11-10 ES ES04819582T patent/ES2327646T3/en active Active
- 2004-11-10 WO PCT/EP2004/012711 patent/WO2005053877A2/en active Application Filing
- 2004-11-10 DK DK04819582T patent/DK1697070T3/en active
- 2004-11-10 AU AU2004295039A patent/AU2004295039B2/en not_active Ceased
- 2004-11-10 EP EP04819582A patent/EP1697070B1/en not_active Revoked
- 2004-11-10 DE DE502004009542T patent/DE502004009542D1/en active Active
- 2004-11-10 KR KR1020067013079A patent/KR101165478B1/en active IP Right Grant
- 2004-11-10 US US10/581,385 patent/US7789123B2/en active Active
- 2004-11-10 AT AT04819582T patent/ATE432135T1/en active
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013083391A1 (en) | 2011-12-05 | 2013-06-13 | Siemens Vai Metals Technologies Gmbh | Process engineering measures in a strand casting machine at the beginning of casting, at the end of casting, and during the manufacturing of a transition piece |
Also Published As
Publication number | Publication date |
---|---|
AT413084B (en) | 2005-11-15 |
KR101165478B1 (en) | 2012-07-13 |
KR20060121255A (en) | 2006-11-28 |
ES2327646T3 (en) | 2009-11-02 |
EP1697070A2 (en) | 2006-09-06 |
AU2004295039A1 (en) | 2005-06-16 |
DK1697070T3 (en) | 2009-09-14 |
WO2005053877A3 (en) | 2005-11-10 |
US20080173423A1 (en) | 2008-07-24 |
AU2004295039B2 (en) | 2009-10-29 |
WO2005053877A2 (en) | 2005-06-16 |
DE502004009542D1 (en) | 2009-07-09 |
US7789123B2 (en) | 2010-09-07 |
ATA19272003A (en) | 2005-04-15 |
ATE432135T1 (en) | 2009-06-15 |
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