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EP0992299A1 - Process for producing steel - Google Patents

Process for producing steel Download PDF

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Publication number
EP0992299A1
EP0992299A1 EP99250167A EP99250167A EP0992299A1 EP 0992299 A1 EP0992299 A1 EP 0992299A1 EP 99250167 A EP99250167 A EP 99250167A EP 99250167 A EP99250167 A EP 99250167A EP 0992299 A1 EP0992299 A1 EP 0992299A1
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EP
European Patent Office
Prior art keywords
steel
mgo
slag
cao
ladle
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Granted
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EP99250167A
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German (de)
French (fr)
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EP0992299B1 (en
Inventor
Arnold Pfeiffer
Heinz-Peter Kaiser
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Vodafone GmbH
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Mannesmann AG
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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
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • 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

Definitions

  • the invention relates to a method for producing steel with a Carbon content equal to / less than 0.9 percent by weight and an Si content of 0.15 - 1.0 percent by weight according to the preamble of claim 1.
  • An essential quality feature of a steel is the degree of purity. It is significantly influenced by the oxygen dissolved in the steel, which should be equal to or less than 20 ppm in order to prevent oxidation with manganese and silicon.
  • the process of so-called full sedation by adding aluminum has prevailed. Since aluminum has a high affinity for oxygen, such an addition releases the still dissolved oxygen and forms Al 2 O 3 partially mixed with MgO.
  • the alumina particles are naturally small, but have a high melting point, so that they can cake together during continuous casting, particularly in the turbulent areas. This is called in English clogging ". Through this clogging effect increases the immersion spout, so that the flow rate changes constantly and there is a risk that larger particles are entrained, which leads to a corresponding contamination of the steel.
  • One of the known remedial measures is the calcium treatment of the steel, which is disadvantageous due to the formation of liquid aluminates clogging ".
  • Another remedial measure is the supply of argon to the stopper or slide of the distribution channel.
  • Another possibility is to provide the immersion spout with a channel opening in the inlet area, or to arrange a flushing stone in the perforated brick, in order in this way to add argon All of the above measures make it more difficult for the alumina particles to cake together.
  • a disadvantage of this treatment is the possible inclusion of argon bubbles, which do not weld during rolling. Usually the argon bubbles are mixed with alumina particles, so that this often leads to surface defects on the end products .
  • DE 25 27 156 A1 describes a method for producing a molten steel for the continuous casting process in which one from a melting unit Retain the fresh slag containing FeO tapped into a ladle sulfur-containing initial melt by adding silicon and / or aluminum deoxidized, mixed with alloying elements and possibly a vacuum treatment is subjected.
  • Step on the material produced by the continuous casting process typical errors such as segregation cracks, core segregations and accumulations of non-metallic inclusions.
  • the segregating elements include in molten steel dissolved oxygen and sulfur. Avoiding the The aforementioned error can be achieved if the steel to be cast in the strand contains practically no dissolved oxygen and no sulfur.
  • the Lowering sulfur can be done by adding calcium and lowering oxygen reach over silicon and especially aluminum.
  • the deoxidized melt with calcium treatment agents post-treatment the amount of calcium carriers is greater than for the Desulfurization and / or toughness adjustment is required.
  • the addition takes place in a lid with a ladle with silica-free, preferably made of dolomite with powdered lime, the 10-30 % silica-free and non-oxygen-releasing flux, e.g. B. fluorspar and / or Alumina are admixed, and the fine-grained in the steel melt at a depth of at least 2000 mm and approx. 300 mm above the pan base with a neutral carrier gas is blown.
  • the object of the invention is to provide a method for producing steel with a carbon content equal to / less than 0.9 percent by weight and an Si content of 0.15-1.0 percent by weight, in which despite deoxidation only with silicon, carbon and manganese without the addition of aluminum, the degree of purity meets the requirements and the continuous casting is free of special measures clogging "can be performed.
  • a silica-setting agent is added as a slag former during tapping and / or during ladle metallurgical treatment.
  • the investigations have shown that this condition alone is not sufficient. In order for the specified deoxidation reaction to proceed quickly, an intensive rinsing treatment must be carried out.
  • One way to do this is through intensive floor washing as part of a vacuum treatment, usually in a stationary degassing system (VD process).
  • a vacuum of less than 100 millibars should preferably be set and the floor flushing should be carried out with a gas flow of at least 4 liters per minute and ton of steel.
  • a neutral flux such as e.g. B. fluorspar up to 10 weight percent has an advantageous effect.
  • the alumina content of the slag must be less than / equal to 10%, preferably ⁇ 5%, since with increasing Al 2 O 3 content there is a reduction-related increase in the Al content in the steel, which in turn leads to the casting problems mentioned at the beginning.
  • the advantage of the proposed method can be seen in the fact that for all steel grades with carbon contents equal to / less than 0.9 weight percent and Si contents between 0.15 and 1.0 weight percent, which do not necessarily have to be treated with aluminum, an addition of Aluminum can be dispensed with for deoxidation.
  • the proposed ladle metallurgical treatment makes this process possible.
  • the sharp reduction in the number of alumina particles present in the steel greatly improves the casting behavior during continuous casting, so that the clogging "effect is avoided.
  • casting performance is evened out and the degree of purity is improved.
  • the deoxidation costs are considerably reduced by saving aluminum, which is considerably more expensive than silicon.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

On tapping into the casting pan and/or on pan treatment with intensive bath rinsing, lime, MgO, dolomite or fluorspar is added as slag former. CaO, MgO or silicic acid as the three main components have the following weight ratios in the casting pan slag: CaO/MgO = 9.0-2.4, and (CaO + MgO)/SiO2. Steel having a carbon content of not more than 0.9 wt.% and a silicon content of 0.15-1.0 wt.% is produced by: bessemerizing pig iron to steel in a basic convertor in a one-stage LD process; slag-free tapping into the casting pan; alloying and deoxidizing with Si, C and Mn without the addition of Al; fine alloying; silicon deoxidizing; and continuously casting the steel. On tapping into the casting pan and/or on pan treatment with intensive bath rinsing, lime, MgO, dolomite or fluorspar is added as slag former. CaO, MgO or silicic acid as the three main components have the following weight ratios in the casting pan slag: CaO/MgO = 9.0-2.4, and (CaO + MgO)/SiO2.

Description

Die Erfindung betrifft ein Verfahren zur Erzeugung von Stahl mit einem Kohlenstoffgehalt gleich/kleiner 0,9 Gewichtsprozent und einem Si-Gehalt von 0,15 - 1,0 Gewichtsprozent gemäß dem Oberbegriff des Patentanspruches 1.The invention relates to a method for producing steel with a Carbon content equal to / less than 0.9 percent by weight and an Si content of 0.15 - 1.0 percent by weight according to the preamble of claim 1.

Ein wesentliches Qualitätsmerkmal eines Stahles ist der Reinheitsgrad. Er wird maßgeblich beeinflußt durch den im Stahl gelösten Sauerstoff, der gleich/kleiner 20 ppm betragen soll, um eine Oxidation mit Mangan und Silizium zu unterbinden. Um diesbezüglich auf der sicheren Seite zu liegen, hat sich das Verfahren einer sogenannten Vollberuhigung durch Zugabe von Aluminium durchgesetzt. Da Aluminium eine hohe Affinität zum Sauerstoff hat, wird durch eine solche Zugabe der noch gelöste Sauerstoff abgebunden und es bildet sich Al2O3 teilweise vermischt mit MgO. Die Tonerdeteilchen sind von Natur aus klein, haben aber einen hohen Schmelzpunkt, so daß sie beim Stranggießen, insbesondere in den Turbulenzgebieten, zusammenbacken können. Dies wird im englischen Sprachgebrauch als

Figure 00010001
clogging" bezeichnet. Durch diesen clogging"-Effekt wächst der Tauchausguß zu, so daß die Durchflußrate sich ständig ändert und die Gefahr besteht, daß größere Teilchen mitgerissen werden, was zu einer entsprechenden Verunreinigung des Stahles führt.An essential quality feature of a steel is the degree of purity. It is significantly influenced by the oxygen dissolved in the steel, which should be equal to or less than 20 ppm in order to prevent oxidation with manganese and silicon. In order to be on the safe side in this regard, the process of so-called full sedation by adding aluminum has prevailed. Since aluminum has a high affinity for oxygen, such an addition releases the still dissolved oxygen and forms Al 2 O 3 partially mixed with MgO. The alumina particles are naturally small, but have a high melting point, so that they can cake together during continuous casting, particularly in the turbulent areas. This is called in English
Figure 00010001
clogging ". Through this clogging effect increases the immersion spout, so that the flow rate changes constantly and there is a risk that larger particles are entrained, which leads to a corresponding contamination of the steel.

Eine der bekannten Abhilfemaßnahmen ist die Kalziumbehandlung des Stahles, die durch Bildung flüssiger Aluminate das nachteilige clogging" vermeidet. Eine weitere Abhilfemaßnahme ist die Zuführung von Argon am Stopfen bzw. Schieber der Verteilerrinne. Eine andere Möglichkeit besteht darin, den Tauchausguß mit einem im Einlaufbereich mündenden Kanal zu versehen, oder im Lochstein einen Spülstein anzuordnen, um auf diese Weise Argon an die kritische Stelle zu leiten. Alle genannten Maßnahmen erschweren das Zusammenbacken der Tonerdeteilchen. Nachteilig bei dieser Behandlung ist der mögliche Einschluß von Argonblasen, die beim Walzen nicht verschweißen. Meistens sind die Argonblasen mit Tonerdeteilchen vermischt, so daß dies häufig zu Oberflächenfehlern an den Endprodukten führt.One of the known remedial measures is the calcium treatment of the steel, which is disadvantageous due to the formation of liquid aluminates clogging ". Another remedial measure is the supply of argon to the stopper or slide of the distribution channel. Another possibility is to provide the immersion spout with a channel opening in the inlet area, or to arrange a flushing stone in the perforated brick, in order in this way to add argon All of the above measures make it more difficult for the alumina particles to cake together. A disadvantage of this treatment is the possible inclusion of argon bubbles, which do not weld during rolling. Mostly the argon bubbles are mixed with alumina particles, so that this often leads to surface defects on the end products .

Aus der DE 195 20 833 C2 ist es bekannt, für übereutektoide Stähle auf eine Desoxidation durch Zugabe von Aluminium zu verzichten und eine kombinierte Desoxidation ausschließlich mit Kohlenstoff, Silizium und Mangan während einer Vakuumbehandlung durchzuführen. Der hohe Kohlenstoffgehalt in Verbindung mit der Druckabsenkung führt in diesem Fall problemlos zu Sauerstoffgehalten kleiner/gleich 10 ppm.From DE 195 20 833 C2 it is known for one to use for hypereutectoid steels To avoid deoxidation by adding aluminum and a combined Deoxidation only with carbon, silicon and manganese during one Perform vacuum treatment. The high carbon content in connection with the In this case, lowering the pressure easily leads to oxygen contents of less than or equal to 10 ppm.

Die Desoxidation über Silizium allein führt nicht zum Ziel, da die Einstellung eines Sauerstoffgehaltes im Stahl unter einen Wert von 40 ppm nicht möglich ist. Bei so hohen Gehalten reagiert aber der Sauerstoff mit Mangan und Silizium, was zu einem schlechten oxidischen Reinheitsgrad führt.Deoxidation via silicon alone does not lead to the goal, since the setting of a Oxygen content in the steel below a value of 40 ppm is not possible. With so high levels, however, the oxygen reacts with manganese and silicon, resulting in a leads to poor oxidic purity.

Aus der DE 25 27 156 A1 ist ein Verfahren zur Herstellung einer Stahlschmelze für das Stranggießverfahren bekannt, bei dem eine aus einem Schmelzaggregat unter Zurückhalten der FeO-haltigen Frischschlacke in eine Gießpfanne abgestochene schwefelhaltige Ausgangsschmelze durch Zusatz von Silizium und / oder Aluminium desoxidiert, mit Legierungselementen versetzt und ggf. einer Vakuumbehandlung unterzogen wird. Bei dem im Stranggießverfahren hergestellten Material treten typische Fehler wie Seigerungsrisse, Kernseigerungen und Anhäufungen von nichtmetallischen Einschlüssen auf. Zu den seigernden Elementen gehören im flüssigen Stahl gelöst verbliebener Sauerstoff und Schwefel. Eine Vermeidung der zuvor genannten Fehler läßt sich erreichen, wenn der im Strang zu vergießende Stahl praktisch keinen gelösten Sauerstoff und keinen Schwefel enthält. Die Schwefelabsenkung läßt sich über Zugabe von Calcium und die Sauerstoffabsenkung über Silizium und insbesondere Aluminium erreichen. Dabei ergeben sich Nachteile, wie höhere erforderliche Gießtemperatur, schlechter oxidischer Reinheitsgrad und Zusetzen der Tauchausgüsse. Zur Lösung des geschilderten Problems wird vorgeschlagen, die desoxidierte Schmelze mit Calcium-Behandlungsmitteln nachzubehandeln, wobei die Menge an Calcium-Trägern größer ist als für die Entschwefelung und / oder die Einstellung der Zähigkeit erforderlich ist. Die Zugabe erfolgt in einer mit einem Deckel versehenen Gießpfanne mit kieselsäurefreier, vorzugsweise aus Dolomit bestehender Zustellung mit pulverförmigem Kalk, dem 10-30 % kieselsäurefreie und nicht sauerstoffabgebende Flußmittel, z. B. Flußspat und / oder Tonerde beigemischt sind, und der in die Stahlschmelze feinkörnig bei einer Tiefe von mindestens 2000 mm und ca. 300 mm oberhalb des Pfannenbodens mit einem neutralen Trägergas eingeblasen wird.DE 25 27 156 A1 describes a method for producing a molten steel for the continuous casting process is known in which one from a melting unit Retain the fresh slag containing FeO tapped into a ladle sulfur-containing initial melt by adding silicon and / or aluminum deoxidized, mixed with alloying elements and possibly a vacuum treatment is subjected. Step on the material produced by the continuous casting process typical errors such as segregation cracks, core segregations and accumulations of non-metallic inclusions. The segregating elements include in molten steel dissolved oxygen and sulfur. Avoiding the The aforementioned error can be achieved if the steel to be cast in the strand contains practically no dissolved oxygen and no sulfur. The Lowering sulfur can be done by adding calcium and lowering oxygen reach over silicon and especially aluminum. There are disadvantages, such as higher required casting temperature, poor oxide purity and Closing the diving spouts. To solve the problem described proposed the deoxidized melt with calcium treatment agents post-treatment, the amount of calcium carriers is greater than for the Desulfurization and / or toughness adjustment is required. The addition takes place in a lid with a ladle with silica-free, preferably made of dolomite with powdered lime, the 10-30 % silica-free and non-oxygen-releasing flux, e.g. B. fluorspar and / or Alumina are admixed, and the fine-grained in the steel melt at a depth of at least 2000 mm and approx. 300 mm above the pan base with a neutral carrier gas is blown.

Aufgabe der Erfindung ist es, ein Verfahren zur Erzeugung von Stahl mit einem Kohlenstoffgehalt gleich/kleiner 0,9 Gewichtsprozent und einem Si-Gehalt von 0,15 - 1,0 Gewichtsprozent anzugeben, bei dem trotz einer Desoxidation nur mit Silizium, Kohlenstoff und Mangan unter Verzicht auf eine Al-Zugabe der Reinheitsgrad den Anforderungen entspricht und das Stranggießen auch ohne Sondermaßnahmen frei von clogging" durchgeführt werden kann.The object of the invention is to provide a method for producing steel with a carbon content equal to / less than 0.9 percent by weight and an Si content of 0.15-1.0 percent by weight, in which despite deoxidation only with silicon, carbon and manganese without the addition of aluminum, the degree of purity meets the requirements and the continuous casting is free of special measures clogging "can be performed.

Diese Aufgabe wird ausgehend vom Oberbegriff in Verbindung mit den kennzeichnenden Merkmalen des Anspruches 1 gelöst. Vorteilhafte Weiterbildungen sind Bestandteil von Unteransprüchen.This task is based on the generic term in conjunction with the characterizing features of claim 1 solved. Advantageous further training are part of subclaims.

Nach der Lehre des Patentes wird beim Abstich und / oder während der pfannenmetallurgischen Behandlung ein Kieselsäure-abbindendes Mittel als Schlackenbildner zugegeben. Dieser Verfahrensweise liegt die Überlegung zugrunde, daß die Aktivität der während der Desoxidation gebildeten Kieselsäure erniedrigt werden muß, um gemäß der Reaktion [Si]+2[O]=(SiO2) K = a(SiO2)a(Si) x a2 [O] mit Hilfe üblicher Si-Gehalte den Sauerstoffgehalt auf gleich/kleiner 20 ppm absenken zu können. Die Untersuchungen haben aber ergeben, daß diese Bedingung allein nicht ausreicht. Damit die angegebene Desoxidationsreaktion zügig abläuft, muß eine intensive Spülbehandlung durchgeführt werden. Hierbei kommt es zur Emulsionsbildung der dünnflüssigen Gießpfannenschlacke mit dem Stahlbad, und die Desoxidationsreaktion kann innerhalb weniger Minuten in der gewünschten Weise ablaufen. Eine Möglichkeit dazu ergibt sich durch intensives Bodenspülen im Rahmen einer Vakuumbehandlung, üblicherweise in einer Standentgasungsanlage (VD-Verfahren). Vorzugsweise soll ein Vakuum kleiner 100 Millibar eingestellt werden und die Bodenspülung mit einem Gasdurchfluß von mindestens 4 Liter pro Minute und Tonne Stahl erfolgen.According to the teaching of the patent, a silica-setting agent is added as a slag former during tapping and / or during ladle metallurgical treatment. This procedure is based on the consideration that the activity of the silica formed during the deoxidation must be reduced in order to be able to react in accordance with the reaction [Si] +2 [O] = (SiO 2 ) K = a (SiO 2nd ) a (Si) xa 2nd [O] to be able to reduce the oxygen content to / less than 20 ppm with the aid of conventional Si contents. However, the investigations have shown that this condition alone is not sufficient. In order for the specified deoxidation reaction to proceed quickly, an intensive rinsing treatment must be carried out. This forms the emulsion of the thin ladle slag with the steel bath, and the deoxidation reaction can proceed in the desired manner within a few minutes. One way to do this is through intensive floor washing as part of a vacuum treatment, usually in a stationary degassing system (VD process). A vacuum of less than 100 millibars should preferably be set and the floor flushing should be carried out with a gas flow of at least 4 liters per minute and ton of steel.

Für die Mehrzahl der Stahlgüten ist eine Entgasung nicht erforderlich und die sekundärmetallurgische Behandlung erfolgt unter Normaldruck. In diesen Fällen ist eine intensive Lanzenspülung mit mindestens 8 Liter pro Minute und Tonne Stahl notwendig, um die für eine Emulsionsbildung erforderliche Badbewegung zu erreichen. Vorteilhafterweise wird die Lanzenspülung mit einer Bodenspülung von mindestens 2 Liter Gasdurchfluß pro Minute und Tonne Stahl kombiniert. Wie bereits weiter oben dargelegt, beruht das erfindungsgemäße Verfahren auf einer möglichst weitgehenden Verminderung der Kieselsäurenaktivität in der Gießpfannenschlacke. Für die dolomitisch oder magnesitisch zugestellte Stahlgießpfanne ergeben sich daher folgende Konzentrationsverhältnisse der drei Hauptbestandteile Calciumoxid, Kieselsäure und Magnesiumoxid:

  • CaO/MgO = 9,0 bis 2,5 vorzugsweise 4,5
  • (CaO+MgO)/SiO2 = 3,5 bis 1,5 vorzugsweise 2,4
    • Degassing is not required for the majority of steel grades and the secondary metallurgical treatment is carried out under normal pressure. In these cases, intensive lance rinsing with at least 8 liters per minute and ton of steel is necessary to achieve the bath movement required for emulsion formation. Advantageously, the lance purging is combined with a floor purging of at least 2 liters of gas flow per minute and ton of steel. As already explained above, the method according to the invention is based on the greatest possible reduction in the silica activity in the ladle slag. The following concentration ratios of the three main components calcium oxide, silica and magnesium oxide therefore result for the dolomitic or magnesitic steel ladle:
  • CaO / MgO = 9.0 to 2.5, preferably 4.5
  • (CaO + MgO) / SiO 2 = 3.5 to 1.5, preferably 2.4

    • Die Zugabe eines neutralen Flußmittels wie z. B. Flußspat bis zu 10 Gewichtsprozent wirkt sich vorteilhaft aus.The addition of a neutral flux such as e.g. B. fluorspar up to 10 weight percent has an advantageous effect.

    Der Tonerdegehalt der Schlacke muß kleiner / gleich 10%, vorzugsweise ≤ 5% betragen, da mit zunehmendem Al2O3-Gehalt ein reduktionsbedingter Anstieg des Al-Gehaltes im Stahl verbunden ist, der wiederum zu den eingangs erwähnten Gießproblemen führt.The alumina content of the slag must be less than / equal to 10%, preferably ≤ 5%, since with increasing Al 2 O 3 content there is a reduction-related increase in the Al content in the steel, which in turn leads to the casting problems mentioned at the beginning.

    Der Vorteil des vorgeschlagenen Verfahrens ist darin zu sehen, daß für alle Stahlgüten mit Kohlenstoffgehalten gleich/kleiner 0,9 Gewichtsprozent und Si-Gehalten zwischen 0,15 und 1,0 Gewichtsprozent, die nicht zwangsläufig mit Aluminium behandelt werden müssen, auf eine Zugabe von Aluminium zur Desoxidation verzichtet werden kann. Wie in den nachfolgenden Beispielen gezeigt wird, macht die vorgeschlagene pfannenmetallurgische Behandlung diesen Verfahrensweg möglich. Die starke Verringerung der Anzahl der im Stahl vorhandenen Tonerdeteilchen verbessert in starkem Maße das Gießverhalten beim Strangguß, so daß der clogging"-Effekt vermieden wird. Außerdem wird Gießleistung vergleichmäßigt und der Reinheitsgrad ist verbessert. Darüber hinaus werden die Desoxidationskosten durch die Einsparung des gegenüber Silizium wesentlich teureren Aluminium beträchtlich gesenkt. The advantage of the proposed method can be seen in the fact that for all steel grades with carbon contents equal to / less than 0.9 weight percent and Si contents between 0.15 and 1.0 weight percent, which do not necessarily have to be treated with aluminum, an addition of Aluminum can be dispensed with for deoxidation. As shown in the examples below, the proposed ladle metallurgical treatment makes this process possible. The sharp reduction in the number of alumina particles present in the steel greatly improves the casting behavior during continuous casting, so that the clogging "effect is avoided. In addition, casting performance is evened out and the degree of purity is improved. In addition, the deoxidation costs are considerably reduced by saving aluminum, which is considerably more expensive than silicon.

    Beispiel 1example 1

    Stahlgüte:Steel grade:
    St35 (beispielsweise als Vormaterial für nahtlose Rohre) Al-freiSt35 (for example as a raw material for seamless pipes) Al-free
    Abstichgewicht:Rack weight:
    260 t (LD-Konverter)260 t (LD converter)
    Abstichanalyse (Gew.-%):Racking analysis (% by weight):

    CC. SiSi MnMn PP SS AlAl NN OO 0,030.03 -- 0,150.15 0,0180.018 0,0300.030 -- 0,00200.0020 0,090.09

    Zugaben in die Gießpfanne beim schlackenfreien Abstich:Additions to the ladle for slag-free tapping:

    1250 kg1250 kg
    FeSi 75%igFeSi 75%
    1560 kg1560 kg
    FeMn 75%igFeMn 75%
    125 kg125 kg
    Kohlecoal
    750 kg750 kg
    Kalklime
    750 kg750 kg
    Dolomitdolomite
    1. Pfannenanalyse (Gew.-%):1. Pan analysis (% by weight):

    CC. SiSi MnMn PP SS AlAl NN OO 0,110.11 0,290.29 0,570.57 0,0190.019 0,0280.028 0,00050.0005 0,00350.0035 0,00600.0060

    Pfannenbehandlung:Pan treatment:

  • 12 Min. Lanzenspülung mit 2500 l/Min Argon12 min. Lance flushing with 2500 l / min argon
  • gleichzeitig Bodenspülung mit 600 l/Min Argonat the same time flushing the floor with 600 l / min argon

    • 2. Pfannenanalyse (Gew.-%):2. Pan analysis (% by weight):

    CC. SiSi MnMn PP SS AlAl NN OO 0,110.11 0,260.26 0,580.58 0,0190.019 0,0060.006 0,0020.002 0,00650.0065 0,00120.0012

    Pfannenschlackenanalyse (Gew.-%):Ladle slag analysis (% by weight):

    CaOCaO SiO2 SiO 2 Al2O3 Al 2 O 3 MgOMgO 5454 2323 77 1414

    Abguß der Schmelze in eine Stranggießanlage, beispielsweise Rundstrangguß Casting of the melt into a continuous caster, for example round casting

    Beispiel 2Example 2

    Stahlgüte:Steel grade:
    Großrohrstahl, Al-freiLarge tube steel, Al-free
    Abstichgewicht:Rack weight:
    250 t (LD-Konverter)250 t (LD converter)
    Abstichanalyse (Gew.-%):Racking analysis (% by weight):

    CC. SiSi MnMn PP SS AlAl NN OO 0,0250.025 -- 0,130.13 0,0100.010 0,0040.004 -- 0,00220.0022 0,09500.0950

    Zugaben in die Gießpfanne beim schlackenfreien Abstich:Additions to the ladle for slag-free tapping:

    1230 kg1230 kg
    FeSi 75%igFeSi 75%
    4600 kg4600 kg
    FeMn affiné 80%igFeMn affine 80%
    1000 kg1000 kg
    Kalklime
    670 kg670 kg
    Dolomitdolomite
    300 kg300 kg
    FlußspatFluorspar
    1. Pfannenanalyse (Gew.-%):1. Pan analysis (% by weight):

    CC. SiSi MnMn PP SS AlAl NN OO 0,0420.042 0,280.28 1,581.58 0,0120.012 0,0040.004 0,00050.0005 0,00400.0040 0,00650.0065

    VD-Behandlung:VD treatment:

  • Vakuumpumpen einschalten, Bodenspülen Gießpfanne mit 2800 l/Min Argon.Switch on vacuum pumps, floor rinse ladle with 2800 l / min argon.
  • Gefäßdruck nach 5 Min. auf 3 Millibar absenken. Nach 15 Min. Ende der Behandlung, Fluten des Gefäßes, Abstellen der BodenspülungReduce the vessel pressure to 3 millibars after 5 minutes. After 15 minutes of treatment, Flooding of the vessel, switching off the floor wash

    • 2. Pfannenanalyse (Gew.-%):2. Pan analysis (% by weight):

    CC. SiSi MnMn PP SS AlAl NN OO 0,00440.0044 0,250.25 1,591.59 0,0120.012 0,0010.001 0,0020.002 0,00350.0035 0,00070.0007

    Pfannenschlackenanalyse (Gew.-%):Ladle slag analysis (% by weight):

    CaOCaO SiO2 SiO 2 Al2O3 Al 2 O 3 MgOMgO 6363 2222 99 44th

    Abguß der Schmelze auf einer Brammenstranggießanlage Casting of the melt on a continuous slab caster

    Der in beiden Beispielen in der 2. Pfannenanalyse vor dem Abstich angegebene Al-Gehalt ist keine Legierungszugabe, sondern ergibt sich durch Verunreinigung der Zugaben. Dieser niedrige Al-Gehalt ist aber unschädlich in bezug auf den nicht erwünschten clogging"-Effekt.The Al content stated in both examples in the second ladle analysis before the tapping is not an alloy addition, but results from contamination of the additions. This low Al content is harmless in relation to the undesired one clogging effect.

    Claims (7)

    Verfahren zur Erzeugung von Stahl mit einem Kohlenstoffgehalt gleich / kleiner 0,9 Gewichtsprozent und einem Si-Gehalt von 0,15- 1,0 Gewichtsprozent mit den Arbeitsschritten Verblasen von Roheisen zu Stahl im basischen Konverter im einstufigen LD-Prozeß schlackenfreies Abstechen in die Gießpfanne Legieren und Desoxidation nur mit Si, C und Mn ohne Zugabe von Al Feinlegieren Silizium-Desoxidation Abgießen des Stahles als Strangguß dadurch gekennzeichnet,
    daß beim Abstich in die Gießpfanne und / oder bei der Pfannenbehandlung bei intensiver Badspülung Kalk und / oder MgO und / oder Dolomit und / oder Flußspat als Schlackenbildner zugegeben wird, wobei die drei Hauptbestandteile Kalziumoxid, Magnesiumoxid und Kieselsäure in der Gießpfannenschlacke folgende Gewichtsverhältnisse aufweisen: CaO / MgO = 9,0 bis 2,4 (CaO+MgO) / SiO2 = 3,5 bis 1,5     Method for producing steel with a carbon content equal to or less than 0.9 percent by weight and an Si content of 0.15-1.0 percent by weight with the steps Blowing of pig iron to steel in a basic converter in a one-step LD process slag-free tapping into the ladle Alloying and deoxidation only with Si, C and Mn without adding Al Fine alloys Silicon deoxidation Casting the steel as a continuous casting characterized,
    that when tapping into the ladle and / or during ladle treatment with intensive bath rinsing, lime and / or MgO and / or dolomite and / or fluorspar is added as a slag generator, the three main components calcium oxide, magnesium oxide and silica in the ladle slag having the following weight ratios: CaO / MgO = 9.0 to 2.4 (CaO + MgO) / SiO 2 = 3.5 to 1.5     Verfahren nach Anspruch 1,
    dadurch gekennzeichnet,
    daß der Tonerdegehalt der Gießpfannenschlacke ≤ 10% ist.    Method according to claim 1,
    characterized,
    that the alumina content of the ladle slag is ≤ 10%.         Verfahren nach Anspruch 2,
    dadurch gekennzeichnet,
    daß der Tonerdegehalt der Gießpfannenschlacke ≤ 5% ist.    Method according to claim 2,
    characterized,
    that the alumina content of the ladle slag is ≤ 5%.         Verfahren nach einem der Ansprüche 1 - 3,
    dadurch gekennzeichnet,
    daß der Stahl vor dem Abgießen in die Stranggußkokille in einer Entgasungsanlage entgast wird mit gleichzeitiger Bodenspülung.     Method according to one of claims 1-3,
    characterized,
    that the steel is degassed in a degassing system with simultaneous floor flushing before pouring into the continuous casting mold.         Verfahren nach Anspruch 4,
    dadurch gekennzeichnet,
    daß ein Vakuum kleiner 100 Millibar eingestellt wird und die Bodenspülung mit einer Spülleistung von mindestens 4 Liter pro Minute und Tonne Stahl erfolgt.    Method according to claim 4,
    characterized,
    that a vacuum is set to less than 100 millibars and the floor is flushed with a flushing rate of at least 4 liters per minute and ton of steel.         Verfahren nach einem der Ansprüche 1 - 3,
    dadurch gekennzeichnet,
    daß die Pfannenbehandlung unter Normaldruck erfolgt mit einer Lanzenspülleistung von mindestens 8 Liter pro Minute und Tonne Stahl.    Method according to one of claims 1-3,
    characterized,
    that the pan treatment takes place under normal pressure with a lance rinsing performance of at least 8 liters per minute and ton of steel.         Verfahren nach Anspruch 6,
    dadurch gekennzeichnet,
    daß die Lanzenspülung kombiniert wird mit einer Bodenspülung mit einer Leistung von mindestens 2 Liter pro Minute und Tonne Stahl.    Method according to claim 6,
    characterized,
    that the lance flushing is combined with a floor flushing with a performance of at least 2 liters per minute and ton of steel.
    EP99250167A 1998-10-07 1999-05-27 Process for producing steel Expired - Lifetime EP0992299B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    DE19847271 1998-10-07
    DE19847271A DE19847271C1 (en) 1998-10-07 1998-10-07 Process for the production of steel with a carbon content equal to or less than 0.9 percent by weight and an Si content of 0.15-1.0 percent by weight

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    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE102009020990A1 (en) 2009-05-12 2010-11-18 Heraeus Electro-Nite International N.V. Floor spout for use in a container for molten metal

    Citations (5)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US3822735A (en) * 1969-07-11 1974-07-09 Nat Steel Corp Process for casting molten silicon-aluminum killed steel continuously
    DE2527156A1 (en) * 1975-06-18 1976-12-30 Thyssen Niederrhein Ag PROCESS FOR PRODUCING A MELT STEEL FOR CONTINUOUS CASTING
    JPS609829A (en) * 1983-06-25 1985-01-18 Nippon Stainless Steel Co Ltd Manufacturing method of austenitic stainless steel plate for road mirrors
    JPH04110413A (en) * 1990-08-31 1992-04-10 Nkk Corp Manufacturing method of high carbon steel wire rod
    DE19520833A1 (en) * 1994-06-16 1995-12-21 Mannesmann Ag Process for the production of a seamless hot-worked pipe

    Family Cites Families (1)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US4842642A (en) * 1988-01-19 1989-06-27 Hamilton Specialty Bar Division Of Slater Industries Inc. Additive for promoting slag formation in steel refining ladle

    Patent Citations (5)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US3822735A (en) * 1969-07-11 1974-07-09 Nat Steel Corp Process for casting molten silicon-aluminum killed steel continuously
    DE2527156A1 (en) * 1975-06-18 1976-12-30 Thyssen Niederrhein Ag PROCESS FOR PRODUCING A MELT STEEL FOR CONTINUOUS CASTING
    JPS609829A (en) * 1983-06-25 1985-01-18 Nippon Stainless Steel Co Ltd Manufacturing method of austenitic stainless steel plate for road mirrors
    JPH04110413A (en) * 1990-08-31 1992-04-10 Nkk Corp Manufacturing method of high carbon steel wire rod
    DE19520833A1 (en) * 1994-06-16 1995-12-21 Mannesmann Ag Process for the production of a seamless hot-worked pipe

    Non-Patent Citations (2)

    * Cited by examiner, † Cited by third party
    Title
    PATENT ABSTRACTS OF JAPAN vol. 009, no. 119 (C - 282) 23 May 1985 (1985-05-23) *
    PATENT ABSTRACTS OF JAPAN vol. 016, no. 358 (C - 0970) 4 August 1992 (1992-08-04) *

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    DE59904362D1 (en) 2003-04-03
    ATE233142T1 (en) 2003-03-15

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