WO2001086017A1 - Method and installation for galvanizing a steel strip - Google Patents
Method and installation for galvanizing a steel strip Download PDFInfo
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- WO2001086017A1 WO2001086017A1 PCT/EP2001/004810 EP0104810W WO0186017A1 WO 2001086017 A1 WO2001086017 A1 WO 2001086017A1 EP 0104810 W EP0104810 W EP 0104810W WO 0186017 A1 WO0186017 A1 WO 0186017A1
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- steel strip
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
- C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
- C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
- C23C2/29—Cooling or quenching
Definitions
- the invention relates to a method for galvanizing a steel strip, in which the steel strip is a
- the invention further relates to a system for galvanizing a steel strip with a plurality of treatment devices arranged one behind the other, namely a coating device for zinc, a continuous furnace and in particular a warming zone, with strip guiding and transport means that guide the steel strip through the various treatment devices, and with a control device that the Controls furnace output as a function of measured values of at least one measuring device arranged behind the continuous furnace for a characteristic value of the strip surface, in particular an emission radiation measuring device.
- a steel strip is coated with zinc and then heat-treated (diffusion annealed). During this heat treatment, the zinc coating alloys with iron from the Steel strip, so that an iron-zinc alloy layer with about 90% zinc and 10% iron is formed. While a galvanized strip surface has a silvery shine, an iron-zinc alloy layer is mouse gray and matt if it is alloyed, while only areas that are alloyed are lighter. In the case of an optimally treated steel strip, the coating is alloyed down to the edge areas. The edge areas, on the other hand, are only alloyed due to a process-related slightly thicker zinc layer and lower treatment temperatures.
- Radiation emission from the strip surface during or after the heat treatment (EP 0 564 437 AI).
- the heat treatment is carried out by controlling the heating power of a continuous furnace. It is based on the alleged knowledge that the through reaction (optimal alloy state) can be recognized by a strong increase in the emission radiation. In order to avoid an overreaction during the steel strip passing through the continuous furnace and possibly the warming zones, it is necessary to determine the emission radiation of the surface of the strip at several points of the continuous furnace and the warming zones lying one behind the other. Only then can you intervene in the right place at the right place in a timely manner.
- the invention has for its object to provide a method and a system for galvanizing a steel strip with a Zn-Fe alloy layer, in which or in which an optimal alloy state of the Zn-Fe alloy layer can be achieved.
- This object is achieved according to the invention in the method mentioned at the outset that, in the event of a control deviation of the characteristic measured values of the emission radiation or the gray value of the steel strip recorded as a controlled variable, the furnace performance in the middle and in the edge regions thereof in the sense of an approximation to those which are decisive for an optimal alloy state of the strip surface , corresponding characteristic values are adjusted.
- the object is achieved in that the measuring device supplies measured values for the radiation emission of the strip surface in the central region of the steel strip and on its edges, and the control device forms the manipulated variable for the furnace output from the comparison of these measured values.
- the invention is based on the knowledge that the alloy state of the Zn-Fe layer of the steel strip can be determined very precisely by comparing the emission radiation or the gray value of the strip surface in the middle of the strip with the corresponding values at the strip edges. This is due to the fact that the emission radiation is the greatest in an optimal alloy state or the gray value is medium gray and matt, while the emission radiation is lower or the gray value is lighter and glossy in the case of a non-optimal alloy state. That is why the invention also sees According to one embodiment, the furnace output is adjusted in terms of a maximum of the difference value for the emission radiation or the gray value of the steel strip, which is determined from the mean values of the emission radiation or the gray value of the steel strip in the middle area and in the peripheral areas.
- the manipulated variable formed from these measured values for the control serving for fine control
- a manipulated variable formed from the measured values of the emission radiation and / or temperature of the steel strip measured at the exit of the furnace serves for a rough control. Since, as a rule, alloying at the outlet of the furnace has not yet taken place, but rather temperature treatment in the holding zone is still required for the alloying, exclusive regulation depending on the measured values within or at the end of the holding zones would result in an undesirable late reaction in the Adjust the furnace output. However, since the expected state of the alloy can already be roughly recognized at the exit of the furnace, it is advantageous to derive a first manipulated variable from a measured value at this point, so that only a fine control has to be carried out afterwards.
- FIG. 1 shows a system for galvanizing a steel strip with subsequent heat treatment in a schematic illustration
- Figure 2 shows a system for galvanizing a steel strip with subsequent heat treatment in a schematic representation in a different embodiment to Figure 1
- FIG. 3 shows a diagram for the emission radiation as a function of the furnace output.
- a steel strip 1 is passed over a roll 2a through a bath 2b made of liquid zinc of a coating system 2. Scraper nozzles 3 scrape off excess zinc.
- the steel strip then passes into a continuous furnace 4 with a series of induction coils with which the heating power of the continuous furnace 4 can be controlled.
- a measuring device for the emission radiation and the temperature 5, namely a special pyrometer, is arranged at the outlet of the furnace 4.
- the steel strip 1 then passes through two warming zones 6, 7, namely a stationary 6 and a movable 7. At the exit of the warming zone 7, a measuring device 8a, 8b for the emission radiation of the surfaces of the steel strip 1 is arranged on each side of the steel strip.
- measuring devices 8a, 8b are able, on the one hand, to detect the emission radiation in the areas of both band edges and, on the other hand, in the central area of the steel band and to supply corresponding measured values for this.
- the steel strip 1 then passes through a cooling zone 9 in order to then be transported further via a deflection roller 10, for example to a reel.
- the measuring devices 5, 8a, 8b deliver measured values about the emission radiation to a controller 11.
- the measuring device 5 provides, for example, a measured value for the average emission of the steel strip 1.
- the measuring devices 8a, 8b supply differentiated measured values, specifically measured values for the regions of the band edges and for the middle band region.
- the controller 11 processes the measured value of the measuring device 5 into a manipulated variable in order initially to roughly adapt the performance of the continuous furnace. Average values are initially formed from the measured values for the radiation emission supplied by the measuring devices 8a, 8b. The mean values are compared with each other by forming the difference from them:
- E rRand mean value of the emission radiation on the right
- the size ⁇ E is plotted against the furnace output. It can be seen that the difference between the mean values of the emission radiation has its maximum at a certain furnace output.
- the Zn-Fe layer of the metal strip is at this maximum optimally alloyed. Only narrow areas at the edges of the strip, in which a thicker zinc layer has formed due to the process and / or which have not been optimally heat-treated and are cut off when the metal strip is trimmed anyway, are only alloyed.
- Figure 2 shows a corresponding embodiment. To the extent that there are similarities with the first exemplary embodiment, the corresponding system parts are provided with the same reference symbols.
- the continuous furnace 4 consists of only one induction coil, while an additional movable warming zone 6 * is provided.
- the special pyrometers 5 can be arranged behind each warming zone 6, 6 *, 7.
- Measuring devices 11a, 11b are provided in the form of cameras, which record measured values for gray values of the steel strip 1 illuminated by lighting devices 12a, 12b, specifically measured values for the two edge regions and for the middle band region. These measured values are processed in the same way as the measured values for radiation emission are processed in the exemplary embodiment in FIG. 1.
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Abstract
Description
Verfahren und Anlage zum Verzinken eines StahlbandesProcess and plant for galvanizing a steel strip
Die Erfindung betrifft ein Verfahren zum Verzinken eines Stahlbandes, bei dem das Stahlband eineThe invention relates to a method for galvanizing a steel strip, in which the steel strip is a
Beschichtungsanlage und einen sich daran anschließenden Durchlaufofen und insbesondere eine nachfolgende Wärmebehandlungszone durchläuft, in dem das Stahlband zur Bildung einer Zn-Fe-Schicht in Abhängigkeit von einem am Ausgang des Ofens gemessenen charakteristischen Wert der Bandoberfläche, insbesondere der Emissionsstrahlung, durch Steuerung der Ofenleistung wärmebehandelt wird.Coating plant and a subsequent continuous furnace and in particular a subsequent heat treatment zone in which the steel strip is heat-treated to form a Zn-Fe layer depending on a characteristic value of the strip surface measured at the outlet of the furnace, in particular the emission radiation, by controlling the furnace output ,
Die Erfindung betrifft ferner eine Anlage zum Verzinken eines Stahlbandes mit mehreren hintereinander angeordneten Behandlungseinrichtungen, und zwar einer Beschichtungseinrichtung für Zink, einem Durchlaufofen und insbesondere einer Warmhaltezone, mit Bandführungsund Transportmitteln, die das Stahlband durch die verschiedenen Behandlungseinrichtungen leiten, und mit einer Regeleinrichtung, die die Ofenleistung in Abhängigkeit von Meßwerten mindestens einer hinter dem Durchlaufofen angeordneten Meßeinrichtung für einen charakteristischen Wert der Bandoberfläche, insbesondere einer Emissionsstrahlungsmeßeinrichtung, steuert.The invention further relates to a system for galvanizing a steel strip with a plurality of treatment devices arranged one behind the other, namely a coating device for zinc, a continuous furnace and in particular a warming zone, with strip guiding and transport means that guide the steel strip through the various treatment devices, and with a control device that the Controls furnace output as a function of measured values of at least one measuring device arranged behind the continuous furnace for a characteristic value of the strip surface, in particular an emission radiation measuring device.
Zur Herstellung von Galvannealed Feinblech wird ein Stahlband mit Zink überzogen und anschließend wärmebehandelt (diffusionsgeglüht) . Bei dieser Wärmebehandlung legiert der Zinküberzug mit Eisen aus dem Stahlband, so daß eine Eisen-Zink-Legierungsschicht mit etwa 90 % Zinkanteil und 10 % Eisenanteil entsteht. Während eine verzinkte Bandoberfläche silbrig glänzt, ist eine Eisen-Zink-Legierungsschicht mausgrau und matt, wenn sie durchlegiert ist, während nur anlegierte Bereiche heller sind. Bei einem optimal behandelten Stahlband ist die Beschichtung bis auf die Randbereiche durchlegiert. Die Randbereiche sind dagegen wegen einer prozeßbedingt etwas dickeren Zinkschicht und geringerer Behandlungstemperaturen nur anlegiert.To produce Galvannealed sheet, a steel strip is coated with zinc and then heat-treated (diffusion annealed). During this heat treatment, the zinc coating alloys with iron from the Steel strip, so that an iron-zinc alloy layer with about 90% zinc and 10% iron is formed. While a galvanized strip surface has a silvery shine, an iron-zinc alloy layer is mouse gray and matt if it is alloyed, while only areas that are alloyed are lighter. In the case of an optimally treated steel strip, the coating is alloyed down to the edge areas. The edge areas, on the other hand, are only alloyed due to a process-related slightly thicker zinc layer and lower treatment temperatures.
Bei einem bekannten Verfahren und einer bekannten Anlage zum Verzinken eines Stahlbandes, bei dem nach dem Beschichten des Stahlbandes mit Zink eine Wärmebehandlung des Stahlbandes zum Zwecke der Umwandlung der Zinkschicht in eine Zn-Fe-Legierungsschicht erfolgt, erfolgt die Wärmebehandlung in Abhängigkeit von derIn a known method and a known plant for galvanizing a steel strip, in which after the steel strip has been coated with zinc, the steel strip is heat-treated for the purpose of converting the zinc layer into a Zn-Fe alloy layer, the heat treatment is carried out as a function of
Strahlungsemission der Bandoberfläche während oder nach der Wärmebehandlung (EP 0 564 437 AI) . Die Wärmebehandlung erfolgt über die Steuerung der Heizleistung eines Durchlaufofens . Sie basiert auf der angeblichen Erkenntnis, daß die Durchreaktion (optimaler Legierungszustand) an einem starken Anstieg der Emissionsstrahlung zu erkennen ist. Um eine Überreaktion während des den Durchlaufofen und gegebenenfalls die Warmhaltezonen durchlaufenden Stahlbandes zu vermeiden, ist es erforderlich, die Emissionsstrahlung der Bandoberfläche an mehreren hintereinander liegenden Stellen des Durchlaufofens und der Warmhaltezonen zu ermitteln. Nur dann läßt sich am richtigen Ort rechtzeitig steuernd in die Wärmebehandlung eingreifen.Radiation emission from the strip surface during or after the heat treatment (EP 0 564 437 AI). The heat treatment is carried out by controlling the heating power of a continuous furnace. It is based on the alleged knowledge that the through reaction (optimal alloy state) can be recognized by a strong increase in the emission radiation. In order to avoid an overreaction during the steel strip passing through the continuous furnace and possibly the warming zones, it is necessary to determine the emission radiation of the surface of the strip at several points of the continuous furnace and the warming zones lying one behind the other. Only then can you intervene in the right place at the right place in a timely manner.
Es ist nicht bekannt, ob dieses bekannte Verfahren und diese bekannte Anlage bereits Eingang in die Praxis gefunden haben und sich bewährt haben. Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren und eine Anlage zum Verzinken eines Stahlbandes mit einer Zn-Fe-Legierungsschicht zu schaffen, bei dem beziehungsweise bei der ein optimaler Legierungszustand der Zn-Fe-Legierungsschicht erzielbar ist.It is not known whether this known method and this known system have already found their way into practice and have proven themselves. The invention has for its object to provide a method and a system for galvanizing a steel strip with a Zn-Fe alloy layer, in which or in which an optimal alloy state of the Zn-Fe alloy layer can be achieved.
Diese Aufgabe wird erfindungsgemäß beim eingangs genannten Verfahren dadurch gelöst, daß bei einer Regelabweichung der als Regelgröße erfaßten charakteristischen Meßwerte der Emissionsstrahlung oder des Grauwertes des Stahlbandes in dessen mittlerem und in dessen Randbereichen die Ofenleistung im Sinne einer Angleichung an die für einen optimalen Legierungszustand der Bandoberfläche maßgeblichen, entsprechenden charakteristischen Werte angepaßt wird.This object is achieved according to the invention in the method mentioned at the outset that, in the event of a control deviation of the characteristic measured values of the emission radiation or the gray value of the steel strip recorded as a controlled variable, the furnace performance in the middle and in the edge regions thereof in the sense of an approximation to those which are decisive for an optimal alloy state of the strip surface , corresponding characteristic values are adjusted.
Anlagenmäßig wird die Aufgabe dadurch gelöst, daß die Meßeinrichtung Meßwerte für die Strahlungsemission der Bandoberfläche im mittleren Bereich des Stahlbandes und an dessen Rändern liefert und die Regeleinrichtung die Stellgröße für die Ofenleistung aus dem Vergleich dieser Meßwerte bildet.In terms of the system, the object is achieved in that the measuring device supplies measured values for the radiation emission of the strip surface in the central region of the steel strip and on its edges, and the control device forms the manipulated variable for the furnace output from the comparison of these measured values.
Die Erfindung basiert auf der Erkenntnis, daß der Legierungszustand der Zn-Fe-Schicht des Stahlbandes sehr genau durch den Vergleich der Emissionsstrahlung oder des Grauwertes der Bandoberfläche in der Bandmitte mit den entsprechenden Werten an den Bandrändern festgestellt werden kann. Dies liegt daran, daß bei einem optimalen Legierungszustand die Emissionsstrahlung am größten ist beziehungsweise der Grauwert mittelgrau und matt ist, während bei einem nicht optimalen Legierungszustand die Emissionsstrahlung geringer beziehungsweise der Grauwert heller und glänzend ist. Deshalb sieht die Erfindung auch nach einer Ausgestaltung vor, die Anpassung der Ofenleistung im Sinne eines Maximums des Differenzwertes für die Emissionsstrahlung oder den Grauwert des Stahlbandes vorzunehmen, der aus den Mittelwerten der Emissionsstrahlung oder des Grauwertes des Stahlbandes im mittleren Bereich und in den Randbereichen ermittelt wird.The invention is based on the knowledge that the alloy state of the Zn-Fe layer of the steel strip can be determined very precisely by comparing the emission radiation or the gray value of the strip surface in the middle of the strip with the corresponding values at the strip edges. This is due to the fact that the emission radiation is the greatest in an optimal alloy state or the gray value is medium gray and matt, while the emission radiation is lower or the gray value is lighter and glossy in the case of a non-optimal alloy state. That is why the invention also sees According to one embodiment, the furnace output is adjusted in terms of a maximum of the difference value for the emission radiation or the gray value of the steel strip, which is determined from the mean values of the emission radiation or the gray value of the steel strip in the middle area and in the peripheral areas.
Besonders vorteilhaft ist es hinsichtlich einer kurzen Totzeit für die Regelung, wenn bei einem Durchlaufofen und einer anschließenden Warmhaltezone die Messung der Emissionsstrahlung oder des Grauwertes innerhalb und/oder am Ende der Warmhaltezone erfolgt, wobei die aus diesen Meßwerten für die Regelung gebildete Stellgröße der Feinregelung dient, während eine aus den Meßwerten der am Ausgang des Ofens gemessenen Emissionsstrahlung und/oder Temperatur des Stahlbandes gebildete Stellgröße einer Grobregelung dient. Da in der Regel eine Durchlegierung am Ausgang des Ofens noch nicht erfolgt ist, sondern für die Durchlegierung noch die Temperaturbehandlung in der Warmhaltezone benötigt wird, würde eine ausschließliche Regelung in Abhängigkeit von den Meßwerten innerhalb oder am Ende der Warmhaltezonen zu einer unerwünscht späten Reaktion bei der Anpassung der Ofenleistung führen. Da aber auch am Ausgang des Ofens schon grob der zu erwartende Legierungszustand zu erkennen ist, ist es vorteilhaft, von einem Meßwert an dieser Stelle schon eine erste Stellgröße abzuleiten, so daß nachher nur noch eine Feinregelung zu erfolgen hat.It is particularly advantageous with regard to a short dead time for the control if the emission radiation or the gray value is measured within and / or at the end of the warming zone in a continuous furnace and a subsequent warming zone, the manipulated variable formed from these measured values for the control serving for fine control , while a manipulated variable formed from the measured values of the emission radiation and / or temperature of the steel strip measured at the exit of the furnace serves for a rough control. Since, as a rule, alloying at the outlet of the furnace has not yet taken place, but rather temperature treatment in the holding zone is still required for the alloying, exclusive regulation depending on the measured values within or at the end of the holding zones would result in an undesirable late reaction in the Adjust the furnace output. However, since the expected state of the alloy can already be roughly recognized at the exit of the furnace, it is advantageous to derive a first manipulated variable from a measured value at this point, so that only a fine control has to be carried out afterwards.
Im folgenden wird die Erfindung anhand einer Zeichnung näher erläutert. Im einzelnen zeigen: Figur 1 eine Anlage zum Verzinken eines Stahlbandes mit anschließender Wärmebehandlung in schematischer Darstellung,The invention is explained in more detail below with reference to a drawing. In detail show: FIG. 1 shows a system for galvanizing a steel strip with subsequent heat treatment in a schematic illustration,
Figur 2 eine Anlage zum Verzinken eines Stahlbandes mit anschließender Wärmebehandlung in schematischer Darstellung in einer zu Figur 1 anderen AusführungFigure 2 shows a system for galvanizing a steel strip with subsequent heat treatment in a schematic representation in a different embodiment to Figure 1
n dn d
Figur 3 ein Diagramm für die Emissionsstrahlung in Abhängigkeit von der Ofenleistung.3 shows a diagram for the emission radiation as a function of the furnace output.
Ein Stahlband 1 wird über eine Rolle 2a durch ein Bad 2b aus flüssigem Zink einer Beschichtungsanlage 2 geleitet. Abstreifdüsen 3 streifen überschüssiges Zink ab. Danach gelangt das Stahlband in einen Durchlaufofen 4 mit einer Reihe von Induktionsspulen, mit denen die Heizleistung des Durchlaufofens 4 steuerbar ist. Am Ausgang des Ofens 4 ist eine Meßeinrichtung für die Emissionsstrahlung und die Temperatur 5, und zwar ein spezielles Pyrometer, angeordnet. Das Stahlband 1 durchläuft dann zwei Warmhaltezonen 6,7, und zwar eine stationäre 6 und eine bewegliche 7. Am Ausgang der Warmhaltezone 7 ist auf jeder Seite des Stahlbandes eine Meßeinrichtung 8a, 8b für die Emissionsstrahlung der Oberflächen des Stahlbandes 1 angeordnet. Diese Meßeinrichtungen 8a, 8b sind in der Lage, einerseits die Emissionsstrahlung in den Bereichen beider Bandränder und andererseits im mittleren Bereich des Stahlbandes zu erfassen und dafür entsprechende Meßwerte zu liefern. Anschließend durchläuft das Stahlband 1 eine Kühlzone 9, um dann über eine Umlenkrolle 10 beispielsweise zu einem Haspel weitertransportiert zu werden. Die Meßeinrichtungen 5, 8a, 8b liefern an einen Regler 11 Meßwerte über die Emissionsstrahlung. Die Meßeinrichtung 5 liefert beispielsweise einen Meßwert für die mittlere Emission des Stahlbandes 1 . Die Meßeinrichtungen 8a, 8b liefern dagegen differenzierte Meßwerte, und zwar Meßwerte für die Bereiche der Bandränder und für den mittleren Bandbereich. Bei einer typischen Bandbreite von 1000 bis 2000 mm reicht für die Erfassung der Emission im Randbereich eine Breite von 20 mm und im mittleren Bereich eine Breite von 200 mm aus. Den Meßwert der Meßeinrichtung 5 verarbeitet der Regler 11 zu einer Stellgröße, um die Leistung des Durchlaufofens zunächst grob anzupassen. Aus den von den Meßeinrichtungen 8a, 8b gelieferten Meßwerten für die Strahlungsemission werden zunächst Mittelwerte gebildet. Die Mittelwerte werden miteinander verglichen, indem aus ihnen die Differenz gebildet wird:A steel strip 1 is passed over a roll 2a through a bath 2b made of liquid zinc of a coating system 2. Scraper nozzles 3 scrape off excess zinc. The steel strip then passes into a continuous furnace 4 with a series of induction coils with which the heating power of the continuous furnace 4 can be controlled. A measuring device for the emission radiation and the temperature 5, namely a special pyrometer, is arranged at the outlet of the furnace 4. The steel strip 1 then passes through two warming zones 6, 7, namely a stationary 6 and a movable 7. At the exit of the warming zone 7, a measuring device 8a, 8b for the emission radiation of the surfaces of the steel strip 1 is arranged on each side of the steel strip. These measuring devices 8a, 8b are able, on the one hand, to detect the emission radiation in the areas of both band edges and, on the other hand, in the central area of the steel band and to supply corresponding measured values for this. The steel strip 1 then passes through a cooling zone 9 in order to then be transported further via a deflection roller 10, for example to a reel. The measuring devices 5, 8a, 8b deliver measured values about the emission radiation to a controller 11. The measuring device 5 provides, for example, a measured value for the average emission of the steel strip 1. The measuring devices 8a, 8b, on the other hand, supply differentiated measured values, specifically measured values for the regions of the band edges and for the middle band region. With a typical bandwidth of 1000 to 2000 mm, a width of 20 mm is sufficient for the detection of the emission in the edge area and a width of 200 mm in the middle area. The controller 11 processes the measured value of the measuring device 5 into a manipulated variable in order initially to roughly adapt the performance of the continuous furnace. Average values are initially formed from the measured values for the radiation emission supplied by the measuring devices 8a, 8b. The mean values are compared with each other by forming the difference from them:
Λ c _ r? rRand k IRand Λ c _ r ? rBorder k IRand
ΔJrr- - ±- itte ~ oΔJrr- - ± - itte ~ o
(Mit ΔE= Differenz der Mittelwerte der Emissionsstrahlungen in Bandmitte und an den Bandrändern;(With ΔE = difference of the mean values of the emission radiation in the middle of the band and at the band edges;
EMi e = Mittelwert der Emissionsstrahlung in Bandmitte;EMi e = mean value of the emission radiation in the middle of the band;
E rRand = Mittelwert der Emissionsstrahlung am rechtenE rRand = mean value of the emission radiation on the right
Bandrand; E1Rand = Mittelwert der Emissionsstrahlung am linken Bandrand) .Band edge; E 1Ran d = mean value of the emission radiation on the left edge of the band).
Im Diagramm der Figur 3 ist die Größe ΔE über der Ofenleistung aufgetragen. Es ist zu erkennen, daß bei einer bestimmten Ofenleistung die Differenz der Mittelwerte der Emissionsstrahlungen ihr Maximum hat. In diesem Maximum ist die Zn-Fe-Schicht des Metallbandes optimal legiert. Nur schmale Bereiche an den Bandrändern, in denen sich prozeßbedingt eine dickere Zinkschicht gebildet hat und/oder die nicht optimal wärmebehandelt wurden und beim ohnehin notwendigen Besäumen des Metallbandes abgeschnitten werden, sind nur anlegiert. Der charakteristische Verlauf dieser Kurve ist einerseits damit zu erklären, daß bei optimalem Legierungszustand der Beschichtung des Metallbandes in der Bandmitte diese nur anlegierten Bandränder eine geringere Strahlungsemission als der mittlere, optimal legierte Bandbereich haben, andererseits damit, daß bei Erhöhung der Ofenleistung eine weitere Durchlegierung der Zinkschicht an den Bandrändern stattfindet, was sich in einer erhöhten Emissionsstrahlung bemerkbar macht, und gleichzeitig wird das Stahlband im übrigen Bereich überlegiert, ohne daß sich dies in einer wesentlichen Veränderung der Emissionsstrahlung bemerkbar macht. Das bedeutet, daß bei erhöhter Ofenleistung der ermittelte Differenzwert für die Strahlungsemission wieder abnimmt.In the diagram in FIG. 3, the size ΔE is plotted against the furnace output. It can be seen that the difference between the mean values of the emission radiation has its maximum at a certain furnace output. The Zn-Fe layer of the metal strip is at this maximum optimally alloyed. Only narrow areas at the edges of the strip, in which a thicker zinc layer has formed due to the process and / or which have not been optimally heat-treated and are cut off when the metal strip is trimmed anyway, are only alloyed. The characteristic course of this curve can be explained on the one hand by the fact that when the coating of the metal strip in the middle of the strip is in the optimum alloy state, these only alloyed strip edges have a lower radiation emission than the middle, optimally alloyed strip area, and on the other hand that by increasing the furnace output, further alloying of the Zinc layer takes place at the edges of the strip, which is noticeable in increased emission radiation, and at the same time the steel strip is alloyed in the remaining area without this being noticeable in a significant change in the emission radiation. This means that as the furnace output increases, the difference value determined for the radiation emission decreases again.
Das am Beispiel der Strahlungsemission beschriebene Prinzip läßt sich gleichzeitig oder alternativ auch mit dem Grauwert der Bandoberfläche verwirklichen. Figur 2 zeigt dafür ein entsprechendes Ausführungsbeispiel . Soweit mit dem ersten Ausführungsbeispiel Übereinstimmungen bestehen, sind die entsprechenden Anlageteile mit gleichen Bezugszeichen versehen.The principle described using the example of radiation emission can be implemented simultaneously or alternatively with the gray value of the strip surface. Figure 2 shows a corresponding embodiment. To the extent that there are similarities with the first exemplary embodiment, the corresponding system parts are provided with the same reference symbols.
Bei diesem Ausführungsbeispiel besteht der Durchlaufofen 4 aus nur einer Induktionsspule, während eine zusätzliche bewegliche Warmhaltezone 6* vorgesehen ist. Hinter jeder Warmhaltezone 6, 6*, 7 können die speziellen Pyrometer 5 angeordnet sein. Vor allem aber sind anstelle der Meßeinrichtungen 8a, 8b der Figur 1 bei diesem Ausführungsbeispiel hinter der oberen Umlenkrolle 10 Meßeinrichtungen 11a, 11b in Form von Kameras vorgesehen, die Meßwerte für Grauwerte des von Beleuchtungseinrichtungen 12a, 12b beleuchteten Stahlbandes 1 aufnehmen, und zwar Meßwerte für die beiden Randbereiche und für den mittleren Bandbereich. Die Verarbeitung dieser Meßwerte erfolgt in der gleichen Weise wie die Verarbeitung der Meßwerte für die Strahlungsemission beim Ausführungsbeispiel der Figur 1. In this embodiment, the continuous furnace 4 consists of only one induction coil, while an additional movable warming zone 6 * is provided. The special pyrometers 5 can be arranged behind each warming zone 6, 6 *, 7. Above all, however, instead of the measuring devices 8a, 8b of FIG. 1, behind the upper deflection roller 10 in this exemplary embodiment Measuring devices 11a, 11b are provided in the form of cameras, which record measured values for gray values of the steel strip 1 illuminated by lighting devices 12a, 12b, specifically measured values for the two edge regions and for the middle band region. These measured values are processed in the same way as the measured values for radiation emission are processed in the exemplary embodiment in FIG. 1.
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2001260262A AU2001260262A1 (en) | 2000-05-05 | 2001-04-28 | Method and installation for galvanizing a steel strip |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10021948.9 | 2000-05-05 | ||
| DE10021948A DE10021948B4 (en) | 2000-05-05 | 2000-05-05 | Process and plant for galvanizing a steel strip |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2001086017A1 true WO2001086017A1 (en) | 2001-11-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2001/004810 Ceased WO2001086017A1 (en) | 2000-05-05 | 2001-04-28 | Method and installation for galvanizing a steel strip |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2001260262A1 (en) |
| DE (1) | DE10021948B4 (en) |
| WO (1) | WO2001086017A1 (en) |
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| DE102009053368A1 (en) * | 2009-11-14 | 2011-05-19 | Bayerische Motoren Werke Aktiengesellschaft | Process and manufacturing plant for producing a sheet metal part with a corrosion protection coating |
| DE102013113708B3 (en) * | 2013-12-09 | 2015-01-22 | Thyssenkrupp Ag | Device for observing a region of a hot metal strip and / or molten bath in a strip treatment process |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2563537A1 (en) * | 1984-04-25 | 1985-10-31 | Stein Heurtey | Process and device for diffusion annealing for obtaining metal sheets with alloy coating |
| EP0564437A1 (en) * | 1992-03-31 | 1993-10-06 | Voest-Alpine Industrieanlagenbau Gmbh | Process of galvanizing a strip and arrangement for carrying out the process |
| JPH0711413A (en) * | 1993-06-29 | 1995-01-13 | Nisshin Steel Co Ltd | Method and apparatus for controlling alloying degree by emissivity |
| US5785772A (en) * | 1995-12-06 | 1998-07-28 | Bethlehem Steel Corporation | Method and apparatus for controlling galvanneal induction furnace operation |
| EP0921709A2 (en) * | 1997-12-05 | 1999-06-09 | Mitsubishi Heavy Industries, Ltd. | Alloying system and heating control device for high grade galvanized steel sheet |
| EP0992602A1 (en) * | 1998-08-24 | 2000-04-12 | Sms Schloemann-Siemag Aktiengesellschaft | Method and device for quality control and reguation of the galvannealed-coating of steel sheets |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3307968A (en) * | 1963-09-03 | 1967-03-07 | Armco Steel Corp | Method and apparatus for controlling the alloying of zinc coatings |
| AT397815B (en) * | 1992-03-31 | 1994-07-25 | Voest Alpine Ind Anlagen | METHOD FOR GALVANIZING A TAPE AND SYSTEM FOR IMPLEMENTING THE METHOD |
-
2000
- 2000-05-05 DE DE10021948A patent/DE10021948B4/en not_active Expired - Fee Related
-
2001
- 2001-04-28 AU AU2001260262A patent/AU2001260262A1/en not_active Abandoned
- 2001-04-28 WO PCT/EP2001/004810 patent/WO2001086017A1/en not_active Ceased
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2563537A1 (en) * | 1984-04-25 | 1985-10-31 | Stein Heurtey | Process and device for diffusion annealing for obtaining metal sheets with alloy coating |
| EP0564437A1 (en) * | 1992-03-31 | 1993-10-06 | Voest-Alpine Industrieanlagenbau Gmbh | Process of galvanizing a strip and arrangement for carrying out the process |
| JPH0711413A (en) * | 1993-06-29 | 1995-01-13 | Nisshin Steel Co Ltd | Method and apparatus for controlling alloying degree by emissivity |
| US5785772A (en) * | 1995-12-06 | 1998-07-28 | Bethlehem Steel Corporation | Method and apparatus for controlling galvanneal induction furnace operation |
| EP0921709A2 (en) * | 1997-12-05 | 1999-06-09 | Mitsubishi Heavy Industries, Ltd. | Alloying system and heating control device for high grade galvanized steel sheet |
| EP0992602A1 (en) * | 1998-08-24 | 2000-04-12 | Sms Schloemann-Siemag Aktiengesellschaft | Method and device for quality control and reguation of the galvannealed-coating of steel sheets |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 1995, no. 04 31 May 1995 (1995-05-31) * |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10021948B4 (en) | 2004-02-19 |
| AU2001260262A1 (en) | 2001-11-20 |
| DE10021948A1 (en) | 2001-11-22 |
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