EP1112128B1 - Method and device for producing hot-rolled strips and plates - Google Patents

Method and device for producing hot-rolled strips and plates Download PDF

Info

Publication number
EP1112128B1
EP1112128B1 EP99969051A EP99969051A EP1112128B1 EP 1112128 B1 EP1112128 B1 EP 1112128B1 EP 99969051 A EP99969051 A EP 99969051A EP 99969051 A EP99969051 A EP 99969051A EP 1112128 B1 EP1112128 B1 EP 1112128B1
Authority
EP
European Patent Office
Prior art keywords
slab
temperature
transformation
continuous casting
cooling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP99969051A
Other languages
German (de)
French (fr)
Other versions
EP1112128A1 (en
Inventor
Udo Falkenreck
Uwe Quitmann
Harald Wehage
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SMS Siemag AG
Original Assignee
SMS Demag AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SMS Demag AG filed Critical SMS Demag AG
Publication of EP1112128A1 publication Critical patent/EP1112128A1/en
Application granted granted Critical
Publication of EP1112128B1 publication Critical patent/EP1112128B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0218—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for strips, sheets, or plates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B1/30—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a non-continuous process
    • B21B1/32—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a non-continuous process in reversing single stand mills, e.g. with intermediate storage reels for accumulating work
    • B21B1/34—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a non-continuous process in reversing single stand mills, e.g. with intermediate storage reels for accumulating work by hot-rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting

Definitions

  • the invention relates to a method for producing hot strip and sheets a production line consisting of a continuous caster for slabs a thickness between 100 and 180 mm and with an exit temperature from the Continuous caster above 1000 ° C, one heating furnace and one Steckel rolling mill.
  • FFM Flexible Flat Mill
  • the temperature of the slab is usually after leaving the Continuous caster between 1000 ° C and 1150 ° C and decreases during the Transport to the heating furnace on the roller table.
  • the direct hot use in the Heating oven takes place at temperatures between 750 and 950 ° C.
  • the slab evenly across thickness, width and length depending on material Temperatures warmed between 1050 and 1280 ° C.
  • Characteristic for hot use is the fact that before the first forming No or only a slight austenite-ferrite / pearlite conversion in the rolling mill via the slab thickness takes place in the near-surface area when the Surface temperatures are the transition temperatures when transporting the Slab from the continuous caster to the heating furnace not or only slightly and fell short of.
  • the one created with the solidification of the slab Coarse-grained primary austenite remains predominantly in the rolling mill until it is formed receive.
  • the austenite grain size in the heating furnace can vary depending on the material Heating technology is still growing.
  • the method of hot use leads to savings compared to cold use of heating energy and time during the heating process.
  • the described method of hot use has proven itself for steels with a Copper content less than 0.3%. At higher copper contents in the steel, this settles copper released in the heating furnace at the grain boundaries of the Primary austits. Depending on the copper content, the heating temperature and These copper deposits on the grain boundaries during the scaling process Forming in the rolling mill into material separations in the form of net-like cracks to lead.
  • EP 0686702 A1 it is proposed to solve the problem occurring in thin-slab casting and rolling plants, the surface of 40 - lower 70 mm-thick thin slabs in one of the continuous casting plant downstream cooling zone to temperatures below the A r3 temperature such that, in a near-surface region of at least 2 mm depth, there is at least a 70% structural transformation of the austenite into ferrite / pearlite with reorientation of the austenite limits after reheating in the roller hearth furnace.
  • an average surface temperature should not fall below the martensite threshold of the respective material quality.
  • the devices for rapid cooling are localized in the prior art between the continuous caster and the heating or equalizing furnace proposed.
  • the partial conversion of the surface layer into Ferrite / pearlite is with a grain refinement and reorientation of the austenite grain boundaries connected after reheating, as in Figures 1b and 2, also on the course of solid line representing the state of the art can be seen.
  • the object of the present invention is to ensure that in a combined Hot strip / sheet metal production system of the generic type described also Steels with higher contents of Cu, Al and N can be processed without disadvantages can.
  • the surface is completely descaled in the scale washer.
  • the slab is formed with a total decrease of 5-15% and with a diameter-optimized roll gap ratio l d / h m less than 0.8.
  • the rolling speed corresponds to the casting speed.
  • the proposed roll gap ratio of the pressed length to the medium rolling stock height is set such that, according to another feature of the invention, the area near the surface corresponds to a thickness of at most a quarter of the slab thickness by choosing the decrease and the roll gap ratio. while the core area remains almost undeformed.
  • the intensity of the cooling section is controlled and regulated so that the surface temperature of the slab neither reaches the bainite area nor falls below the martensite threshold of the respective material quality.
  • control and regulation systems Media pressure of the nozzle groups of the cooling section depending on the respective Slab thickness and casting speed, the average temperature of the surface layer close to the surface in compliance with for a 100% Microstructure transformation necessary cooling temperature and time as well as the Bainite start temperature and the martensite start temperature of the respective material quality regulate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Metal Rolling (AREA)
  • Control And Other Processes For Unpacking Of Materials (AREA)
  • Thermotherapy And Cooling Therapy Devices (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Abstract

A method for producing hot-rolled strip and plates in a production plant having a continuous casting installation for slabs 100-180 mm thick, descaling sprays, a single- or multiple-stand rolling unit with or without edging, a cooling interval, a heating furnace, and a Steckel mill. Between the continuous casting installation and the heating furnace, only the skin layer of the previously descaled slab is deformed in-line, recrystallized during and after deformation, and then cooled in several stages to a temperature below the Ar3 transformation point and temporarily maintained there until the microstructural transformation of the recrystallized, fine-grained austenite to ferrite/pearlite has been completed.

Description

Die Erfindung betrifft ein Verfahren zur Erzeugung von Warmband und Blechen auf einer Produktionsanlage, bestehend aus einer Stranggießanlage für Brammen mit einer Dicke zwischen 100 und 180 mm und mit einer Austrittstemperatur aus der Stranggießanlage oberhalb von 1000 °C, einem Anwärmofen und einem Steckelwalzwerk.The invention relates to a method for producing hot strip and sheets a production line consisting of a continuous caster for slabs a thickness between 100 and 180 mm and with an exit temperature from the Continuous caster above 1000 ° C, one heating furnace and one Steckel rolling mill.

In einer unter dem Namen FFM (Flexible Flat Mill) bekanntgewordenen Produktionsanlage für die Erzeugung sowohl von Warmband als auch von Blechen wird eine 100 - 180 mm dicke Bramme von der Stranggießanlage mit Hilfe eines Rollgangs direkt zum Anwärmofen transportiert, heiß eingesetzt und angewärmt und nach Verlassen des Anwärmofens in einem ein- oder mehrgerüstigem Steckelwalzwerk zu einem Band oder zu einem oder mehreren Blechen ausgewalzt.In a known as FFM (Flexible Flat Mill) Production plant for the production of both hot strip and sheet is a 100 - 180 mm thick slab from the continuous caster with the help of a Roller tables are transported directly to the heating furnace, used hot and heated and after leaving the heating furnace in a single or multi-stand Steckel rolling mill rolled into a strip or one or more sheets.

Üblicherweise liegt die Temperatur der Bramme nach dem Verlassen der Stranggießanlage zwischen 1000°C und 1150 °C und verringert sich während des Transportes zum Anwärmofen auf dem Rollgang. Der direkte Heißeinsatz in den Anwärmofen erfolgt bei Temperaturen zwischen 750 und 950 °C. Im Anwärmofen wird die Bramme gleichmäßig über Dicke, Breite und Länge auf materialabhängige Temperaturen zwischen 1050 und 1280 °C angewärmt. The temperature of the slab is usually after leaving the Continuous caster between 1000 ° C and 1150 ° C and decreases during the Transport to the heating furnace on the roller table. The direct hot use in the Heating oven takes place at temperatures between 750 and 950 ° C. In the heating furnace the slab evenly across thickness, width and length depending on material Temperatures warmed between 1050 and 1280 ° C.

Kennzeichnend für den Heißeinsatz ist die Tatsache, daß vor der ersten Umformung in der Walzstraße über die Brammendicke keine oder nur eine geringfügige Austenit-Ferrit/Perlit-Umwandlung im oberflächennahen Bereich stattfindet, wenn die Oberflächentemperaturen die Umwandlungstemperaturen beim Transport der Bramme von der Stranggießanlage zum Anwärmofen nicht oder nur geringfügig und kurzzeitig unterschritten hat. Der mit der Erstarrung der Bramme entstandene grobkörnige Primäraustenit bleibt bis zur Umformung in der Walzstraße überwiegend erhalten. Die Austenitkorngröße kann im Anwärmofen materialabhängig und je nach Anwärmtechnologie noch wachsen.Characteristic for hot use is the fact that before the first forming No or only a slight austenite-ferrite / pearlite conversion in the rolling mill via the slab thickness takes place in the near-surface area when the Surface temperatures are the transition temperatures when transporting the Slab from the continuous caster to the heating furnace not or only slightly and fell short of. The one created with the solidification of the slab Coarse-grained primary austenite remains predominantly in the rolling mill until it is formed receive. The austenite grain size in the heating furnace can vary depending on the material Heating technology is still growing.

Das Verfahren des Heißeinsatzes führt im Vergleich zum Kalteinsatz zur Einsparung von Anwärmenergie und -zeit während des Anwärmprozesses.The method of hot use leads to savings compared to cold use of heating energy and time during the heating process.

Das beschriebene Verfahren des Heißeinsatzes hat sich bewährt für Stähle mit einem Kupfergehalt kleiner als 0,3 %. Bei höheren Kupfergehalten im Stahl lagert sich das bei der Zunderbildung im Anwärmofen frei werdende Kupfer an den Korngrenzen des Primäraustenits an. In Abhängigkeit vom Kupfergehalt, der Anwärmtemperatur und Verzunderung können diese Kupferanlagerungen an den Korngrenzen während der Umformung im Walzwerk zu Materialtrennungen in Form von netzartigen Rissen führen.The described method of hot use has proven itself for steels with a Copper content less than 0.3%. At higher copper contents in the steel, this settles copper released in the heating furnace at the grain boundaries of the Primary austits. Depending on the copper content, the heating temperature and These copper deposits on the grain boundaries during the scaling process Forming in the rolling mill into material separations in the form of net-like cracks to lead.

In EP 0686702 A1 wird zur Lösung des auch in Dünnbrammen-Gießwalzanlagen auftretenden Problems vorgeschlagen, die Oberfläche der 40 - 70 mm dicken Dünnbrammen in einer der Stranggießanlage nachgeordneten Kühlstrecke auf Temperaturen unterhalb der Ar3-Temperatur derart abzusenken, daß in einem oberflächennahen Bereich von mindestens 2 mm Tiefe eine mindestens 70%ige Gefügeumwandlung des Austenits in Ferrit/Perlit mit Neuorientierung der Austenitkomgrenzen nach Wiedererwärmung im Rollenherdofen stattfindet. Eine mittlere Oberflächentemperatur soll bei der Abkühlung in der Kühlstrecke die Martensitschwelle der jeweiligen Materialgüte nicht unterschreiten. In EP 0686702 A1 it is proposed to solve the problem occurring in thin-slab casting and rolling plants, the surface of 40 - lower 70 mm-thick thin slabs in one of the continuous casting plant downstream cooling zone to temperatures below the A r3 temperature such that, in a near-surface region of at least 2 mm depth, there is at least a 70% structural transformation of the austenite into ferrite / pearlite with reorientation of the austenite limits after reheating in the roller hearth furnace. When cooling in the cooling section, an average surface temperature should not fall below the martensite threshold of the respective material quality.

Insgesamt ist festzustellen, daß beim Stand der Technik beim Walzen von Blöcken, Knüppeln und Brammen bestimmter chemischer Zusammensetzung Risse bzw. Materialtrennungen auftreten, wenn das Verfahren des Heißeinsatzes in den Anwärmofen als direkte Kopplung von Stranggießanlage und Walzwerk angewendet wird.Overall, it can be stated that in the prior art, when rolling blocks, Billets and slabs of certain chemical composition cracks or Material separations occur when the process of hot use in the Heating furnace used as a direct link between the continuous caster and the rolling mill becomes.

In JP 59-189001 wird für Knüppel aus Kohlenstoffstählen mit 5 - 100 ppm Bor, 0,03 - 0,15 % Schwefel und 0,5 - 2,0 % Silizium ebenfalls eine schnelle Abkühlung der oberflächennahen Randschicht im Bereich zwischen Stranggießanlage und Anwärmofen zur Vermeidung von Rissen im Walzgut während des Walzens vorgeschlagen.In JP 59-189001 for billets made of carbon steels with 5 - 100 ppm boron, 0.03 - 0.15% sulfur and 0.5 - 2.0% silicon also rapidly cool the near the surface in the area between the continuous caster and Heating furnace to avoid cracks in the rolling stock during rolling proposed.

In EP 0587150 A1 werden AIN-Ausscheidungen während des Heißeinsatzes als Ursache für Risse im Walzgut beim Walzen von aluminium-beruhigten Stählen mit 0,008 - 0,030 % N und 0,03 - 0,25 % Pb angegeben. Empfohlen wird eine Schnellabkühlung der oberflächennahen Randschicht der Vorblöcke mit Gefügeumwandlung im Bainitgebiet zur Unterdrückung der AlN-Ausscheidungen. Die Schnellabkühlung findet zwischen Stranggießanlage und Anwärmofen statt.In EP 0587150 A1 AIN excretions during hot use as Cause of cracks in the rolling stock when rolling aluminum-soaked steels 0.008-0.030% N and 0.03-0.25% Pb. One is recommended Rapid cooling of the near-surface boundary layer of the blooms Structural transformation in the bainite region to suppress AlN excretions. The Rapid cooling takes place between the continuous caster and the heating furnace.

Im US - Patent 56 34 512 werden Ausscheidungen von Al, V und N während des Heißeinsatzes als Ursache für Risse in Vorblöcken, Knüppeln und Brammen infolge von Zugspannungen bei der Abkühlung an Luft benannt. Vorgeschlagen wird ebenfalls eine Schnellabkühlung einer oberflächennahen Randschicht von mindestens 10 mm auf eine Temperatur von 400 °C mit anschließendem Selbstanlassen auf 900 °C durch nachfließende Wärme aus dem Kernbereich. Die Einrichtung zur Schnellabkühlung befindet sich zwischen Stranggießanlage und Anwärmofen. Eine materialspezifische Steuerung und Regelung der Abkühleinrichtung ist vorgesehen. In the US patent 56 34 512 excretions of Al, V and N during the Hot use as a cause of cracks in blooms, billets and slabs as a result of tensile stresses during cooling in air. Is proposed also rapid cooling of a surface layer close to the surface of at least 10 mm to a temperature of 400 ° C with subsequent Self-tempering to 900 ° C due to heat flowing from the core area. The The rapid cooling device is located between the continuous caster and Anwärmofen. A material-specific control and regulation of the Cooling device is provided.

Dem geschilderten Stand der Technik ist gemeinsam, daß die eigentlichen Ursachen, Vorgänge bzw. Mechanismen, die zu Rissen und Materialtrennungen bei Nutzung des Heißeinsatzes in der Prozeßlinie Stranggießanlage - Anwärm-/Ausgleichofen - Walzwerk führen, bisher nicht eindeutig geklärt sind. Die Möglichkeit der Kombination mehrerer genannter Ursachen ist gegeben. Generell wird jedoch beim Stand der Technik eine Schnellabkühlung der oberflächennahen Randschicht des Stranggußmaterials unter die Umwandlungstemperatur mit anschließendem Anlassen durch nachfließende Wärme aus dem Kern vorgeschlagen. Die Gefahr der teilweisen Unterschreitung der Oberflächentemperatur unter die Martensitschwelle ist bei allen genannten Patenten gegeben, wie in Figur 1a mit der durchgezogenen, den Stand der Technik darstellenden Linie gezeigt ist. Fig.1a zeigt den Verlauf der Oberflächentemperatur über der Zeit.Common to the described prior art is that the actual causes, Processes or mechanisms that lead to cracks and material separations when using the Hot use in the process line continuous casting plant - heating / equalizing furnace - Rolling mill, have not yet been clearly clarified. The possibility of combination several named causes exist. Generally, however, the status of Technique rapid cooling of the surface layer near the surface of the Continuous casting material below the transition temperature with subsequent tempering suggested by flowing heat from the core. The risk of partial Everyone is below the surface temperature below the martensite threshold given patents, as in Figure 1a with the solid, the state the line representing the technique is shown. Fig.1a shows the course of the Surface temperature over time.

Die Einrichtungen zur Schnellabkühlung werden beim Stand der Technik örtlich zwischen der Stranggießanlage und dem Anwärmofen bzw. Ausgleichofen vorgeschlagen. Die partielle Umwandlung der oberflächennahen Randschicht in Ferrit/Perlit ist mit einer Kornfeinung und Neuorientierung der Austenitkorngrenzen nach Wiedererwärmung verbunden, wie in Figuren 1b und 2, ebenfalls am Verlauf der durchgezogenen, den Stand der Technik darstellenden Linie zu erkennen ist.The devices for rapid cooling are localized in the prior art between the continuous caster and the heating or equalizing furnace proposed. The partial conversion of the surface layer into Ferrite / pearlite is with a grain refinement and reorientation of the austenite grain boundaries connected after reheating, as in Figures 1b and 2, also on the course of solid line representing the state of the art can be seen.

Untersuchungen haben ferner gezeigt, daß bei Stählen mit einem Kupfergehalt größer als 0,3 % und 0,02 - 0,05 % Al sowie 0,008 - 0,020 % N und einem Kupfer/Nickel-Verhältnis größer als 3 ungeachtet einer Schnellabkühlung der oberflächennahen Randschicht einer Bramme mit partieller Gefügeumwandlung nach der Stranggießanlage und vor Einsatz in den Anwärmofen Risse bzw. Materialtrennungen beim nachfolgenden Walzen der Bramme zu Bändern und Blechen auftreten.Studies have also shown that steels with a copper content greater than 0.3% and 0.02 - 0.05% Al and 0.008 - 0.020% N and one Copper / nickel ratio greater than 3 regardless of rapid cooling edge layer near the surface of a slab with partial structural transformation the continuous caster and before use in the heating furnace cracks or Material separations in the subsequent rolling of the slab into strips and Sheet metal occur.

Aufgabe der vorliegenden Erfindung ist es sicherzustellen, daß in einer kombinierten Warmband/Blech-Produktionsanlage der beschriebenen gattungsgemäßen Art auch Stähle mit höheren Gehalten an Cu, Al und N ohne Nachteile verarbeitet werden können. The object of the present invention is to ensure that in a combined Hot strip / sheet metal production system of the generic type described also Steels with higher contents of Cu, Al and N can be processed without disadvantages can.

Erfindungsgemäß wird bei dem gattungsgemäßen Verfahren vorgeschlagen, daß zwischen Stranggießanlage und Anwärmofen nur die oberflächennahe Randschicht der zuvor entzunderten Bramme in-line umgeformt wird, während und nach der Umformung rekristallisiert und anschließend mehrstufig auf eine Temperatur unterhalb des Ar3-Umwandlungspunktes abgekühlt und zeitweise gehalten wird, bis die Gefügeumwandlung des rekristallisierten feinkörnigen Austenits im Ferrit/Perlit abgeschlossen ist.According to the invention, it is proposed in the generic method that between the continuous casting plant and the heating furnace only the surface layer of the previously descaled slab near the surface is formed in-line, recrystallized during and after the forming, and then cooled in several stages to a temperature below the A r3 conversion point and temporarily maintained until the structural transformation of the recrystallized fine-grained austenite in the ferrite / pearlite is completed.

Vorrichtungstechnisch bedeutet das, daß vor dem Einsatz der Bramme in den Anwärmofen eine Oberflächenverformungsgruppe bestehend aus einem Zunderwäscher, einer ein- oder mehrgerüstigen Walzeinheit mit oder ohne integrierten Staucher und einer steuer- und regelbaren Kühlstrecke durchlaufen wird. Im Zunderwäscher wird die Oberfläche vollständig entzundert.Technically, this means that before the slab is used in the Heating furnace a surface deformation group consisting of a Tinder washer, a single or multi-stand rolling unit with or without integrated edger and a controllable and controllable cooling section. The surface is completely descaled in the scale washer.

In einer Weiterbildung der Erfindung ist vorgesehen, daß die Bramme mit einer Gesamtabnahme von 5- 15 % und mit einem durchmesseroptimierten Walzspaltverhältnis ld/hm kleiner als 0,8 umgeformt wird. Die Walzgeschwindigkeit entspricht der Gießgeschwindigkeit. Durch Optimierung des bzw. der Walzendurchmesser und der Abnahme wird das vorgeschlagene Walzspaltverhältnis von gedrückter Länge zu mittlerer Walzguthöhe so eingestellt, daß nach einem anderen Merkmal der Erfindung der oberflächennaher Breich durch Wahl der Abnahme und des Walzspaltverhältnisses einer Dicke von maximal einem Viertel der Brammendicke entspricht, während der Kernbereich nahezu unverformt bleibt.In a development of the invention it is provided that the slab is formed with a total decrease of 5-15% and with a diameter-optimized roll gap ratio l d / h m less than 0.8. The rolling speed corresponds to the casting speed. By optimizing the roll diameter (s) and the decrease, the proposed roll gap ratio of the pressed length to the medium rolling stock height is set such that, according to another feature of the invention, the area near the surface corresponds to a thickness of at most a quarter of the slab thickness by choosing the decrease and the roll gap ratio. while the core area remains almost undeformed.

Durch die Verformung rekristallisiert der oberflächennahe Bereich des Stranggußmaterials im Walzspalt des jeweiligen Gerüstes der Walzeinheit in Abhängigkeit von den Umformbedingungen teilweise bis vollständig dynamisch. Nach Austritt aus dem Walzspalt des jeweiligen Gerüstes der Walzeinheit findet eine teilweise bis vollständige statische Rekristallisation der verformten oberflächennahen Randschicht des Walzgutes statt. Den Temperaturverlauf der oberflächennahen Randschicht zeigt Figur 1a mit der gestrichelten Linie. Durch die dynamische und statische Rekristallisation erfolgt eine Kornfeinung der oberflächennahen Randschicht (vgl. Figur 1b, gestrichelte Linie), d.h. der grobkörnige Primäraustenit ist in eine gewalzte feinkörnige Struktur übergegangen.Due to the deformation, the near-surface area of the Continuous casting material in the roll gap of the respective stand of the rolling unit in Depending on the forming conditions, partially to completely dynamic. To One emerges from the roll gap of the respective stand of the rolling unit partial to complete static recrystallization of the deformed surface near the surface Edge layer of the rolling stock instead. The temperature curve of the surface Figure 1a shows the boundary layer with the dashed line. Due to the dynamic and Static recrystallization results in grain refinement of the surface layer near the surface (see Figure 1b, dashed line), i.e. the coarse-grained primary austenite is in one rolled fine-grained structure.

Zur Vermeidung von Kornwachstum in der oberflächennahen Randschicht aufgrund der noch hohen Temperaturen zwischen 850 und 1050 °C wird diese nach Abschluß der Rekristallisation in einer Kühlstrecke mehrstufig abgekühlt. Bei dieser Abkühlung wird gleichzeitig die Ar3-Umwandlungstemperatur unterschritten, wodurch das durch das Walzen rekristallisierte und gefeinte Korn der oberflächennahen Randschicht im Vergleich zur herkömmlichen Methode 1 bedeutend schneller und zu einem noch feinerem ferritisch/perlitischen Gefüge umwandelt (vgl. Figuren 1 und 2). Erfindungsgemäß wird die Intensität der aus mehreren Düsengruppen bestehenden Kühlstrecke so gesteuert und geregelt wird, daß die Oberflächentemperatur der Bramme weder das Bainitgebiet erreicht noch die Martensitschwelle der jeweiligen Materialgüte unterschreitet.In order to avoid grain growth in the surface layer near the surface due to the still high temperatures between 850 and 1050 ° C., this is cooled in several stages in a cooling section after the recrystallization has been completed. This cooling simultaneously falls below the A r3 transformation temperature, as a result of which the grain of the surface layer near the surface, recrystallized and refined by the rolling, converts significantly faster and to an even finer ferritic / pearlitic structure in comparison to conventional method 1 (see FIGS. 1 and 2). , According to the invention, the intensity of the cooling section consisting of several nozzle groups is controlled and regulated so that the surface temperature of the slab neither reaches the bainite area nor falls below the martensite threshold of the respective material quality.

Die mehrstufige Abkühlung der oberflächennahen Randschicht erfolgt solange, bis eine 100 %ige Umwandlung des rekristallisierten und gefeinten Austenitkorns in Ferrit/Perlit erfolgt ist. Dazu ist vorgesehen, daß Steuer- und Regelsysteme den Mediendruck der Düsengruppen der Kühlstrecke in Abhängigkeit von der jeweiligen Brammendicke und Gießgeschwindigkeit, der mittleren Temperatur der oberflächennahen Randschicht unter Einhaltung der für eine 100 %ige Gefügeumwandlung notwendigen Abkühltemperatur und -zeit sowie der Bainitstarttemperatur und der Martensitstarttemperatur der jeweiligen Materialgüte regulieren.The multi-stage cooling of the surface layer near the surface takes place until a 100% conversion of the recrystallized and refined austenite grain into Ferrite / pearlite is done. For this purpose, it is provided that control and regulation systems Media pressure of the nozzle groups of the cooling section depending on the respective Slab thickness and casting speed, the average temperature of the surface layer close to the surface in compliance with for a 100% Microstructure transformation necessary cooling temperature and time as well as the Bainite start temperature and the martensite start temperature of the respective material quality regulate.

Durch die Kombination von Umformung der oberflächennahen Randschicht mit deren stufenweisen Kühlung unter die Ar3-Umwandlungstemperatur entsteht ein bedeutend feinkörnigeres ferritisch/perlitisches Gefüge bis zum Einsatz der Bramme in den Anwärmofen im Vergleich zu herkömmlichen Methoden (vgl. Figur 1b). Dadurch ist auch eine vollständige Neuorientierung der Austenitkorngrenzen mit einem bedeutend feineren Korn infolge Gefügeumwandlung während der Wiedererwärmung gegeben. The combination of reshaping the surface layer near the surface with its gradual cooling below the A r3 transformation temperature results in a significantly more fine-grained ferritic / pearlitic structure until the slab is used in the heating furnace compared to conventional methods (see Figure 1b). This also gives a complete reorientation of the austenite grain boundaries with a significantly finer grain as a result of structural changes during reheating.

Durch die vollständige Neuorientierung der Austenitkorngrenzen bei bedeutend feinerem Korn können Stähle mit einem Kupfergehalt größer als 0,3 % und Zusätzen von Al und N sowie einem Kupfer/Nickel-Verhältnis größer als 3 im Heißeinsatz auf der beschriebenen Produktionsanlage verarbeitet werden.By completely reorienting the austenite grain boundaries at significant finer grain can be steels with a copper content greater than 0.3% and additives of Al and N and a copper / nickel ratio greater than 3 in hot use the production plant described are processed.

Claims (5)

  1. Method for the production of hot rolled strip and plates in a manufacturing plant consisting of a continuous casting plant for slabs between 100 and 180 mm in thickness, a descaling spray, a single- or multiple-frame roller unit with or without an integrated upsetting device, a cooling line, a heating-up furnace and a Steckel rolling mill,
    characterised in that
    between the continuous casting mill and the heating-up furnace, only the skin layer close to the surface of the previously descaled slab is deformed in-line, re-crystallised during and after the deformation process, and then cooled in several stages to a temperature below the Ar3 transformation point, and temporarily held until the microstructural transformation of the re-crystallised fine-grained austenite to ferrite/pearlite is complete.
  2. Method as in Claim 1,
    characterised in that
    the slab is deformed at a total draught of 5 - 15% and at an optimised gauge roll gap ratio ld / hm of less than 0.8.
  3. Method as in Claim 1 and 2,
    characterised in that
    the deformed area close to the surface corresponds, by selecting the draught and the roll gap ratio, to a maximum depth of one quarter of the thickness of the slab.
  4. Method as in Claim 1 and 3,
    characterised in that
    the intensity of the cooling line, which consists of several groups of nozzles, is controlled and regulated in such a way that the surface temperature of the slab neither reaches the bainite range, nor falls below the martensite threshold of the stock material concerned.
  5. Method as in Claim 1 and 4,
    characterised in that
    control and regulating systems regulate the pressure of the medium from the groups of nozzles in the cooling line, in dependence on the relevant slab thickness and casting speed, the average temperature of the skin layer close to the surface - while maintaining the cooling temperature and period necessary for a 100% microstructure transformation - and the bainite start temperature and the martensite start temperature of the stock material concerned.
EP99969051A 1998-09-14 1999-09-08 Method and device for producing hot-rolled strips and plates Expired - Lifetime EP1112128B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19843200A DE19843200C1 (en) 1998-09-14 1998-09-14 Method for producing hot rolled strip and sheet
DE19843200 1998-09-14
PCT/DE1999/002866 WO2000015362A1 (en) 1998-09-14 1999-09-08 Method and device for producing hot-rolled strips and plates

Publications (2)

Publication Number Publication Date
EP1112128A1 EP1112128A1 (en) 2001-07-04
EP1112128B1 true EP1112128B1 (en) 2003-01-02

Family

ID=7881679

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99969051A Expired - Lifetime EP1112128B1 (en) 1998-09-14 1999-09-08 Method and device for producing hot-rolled strips and plates

Country Status (10)

Country Link
US (1) US6451136B1 (en)
EP (1) EP1112128B1 (en)
CN (1) CN1142038C (en)
AT (1) ATE230315T1 (en)
AU (1) AU1149200A (en)
CA (1) CA2344423C (en)
DE (2) DE19843200C1 (en)
ES (1) ES2186438T3 (en)
RU (1) RU2224605C2 (en)
WO (1) WO2000015362A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2951198B1 (en) * 2009-10-12 2013-05-10 Snecma THERMAL TREATMENTS OF STAINLESS STEEL MARTENSITIC STEELS AFTER REFUSION UNDER DAIRY
DE102013212951A1 (en) 2013-07-03 2015-01-22 Sms Siemag Ag Casting rolling mill and method for producing metallic rolling stock
CN105195700A (en) * 2014-06-23 2015-12-30 鞍钢股份有限公司 Method for avoiding surface cracks of directly-installed rolled thick plate
RU2660504C1 (en) * 2017-05-10 2018-07-06 Николай Петрович Белокопытов Method of production of stainless steel wide thick sheets
EP3769862A1 (en) * 2019-07-24 2021-01-27 Primetals Technologies Austria GmbH Method for producing a deep-drawable ready-made strip made of steel in a casting roller composite system
CN111876664B (en) * 2020-06-19 2022-04-12 江阴兴澄特种钢铁有限公司 Manufacturing method of 50CrVA hot-rolled wide spring steel plate

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58164751A (en) * 1982-03-23 1983-09-29 Daido Steel Co Ltd Cold forging steel and its manufacture
JPS59189001A (en) * 1983-04-08 1984-10-26 Sumitomo Electric Ind Ltd Method for rolling hot billet by direct feeding
JPS62212001A (en) * 1986-03-13 1987-09-18 Sumitomo Metal Ind Ltd Hot rolling method for preventing surface cracking of ingot
JPS63168260A (en) * 1986-12-30 1988-07-12 Aichi Steel Works Ltd Hot working method for continuously cast billet
JPH0688125A (en) * 1992-09-09 1994-03-29 Aichi Steel Works Ltd Method for hot-working continuously cast slab and steel ingot
US5464246A (en) * 1993-02-19 1995-11-07 Simula Inc. Inflatable tubular cushions for crash protection of seated automobile occupants
ES2181698T3 (en) * 1993-10-29 2003-03-01 Danieli Off Mecc METHOD FOR THERMAL SURFACE TREATMENT IN A CONTINUOUS COLADA MACHINE AND CORRESPONDING DEVICE.
DE4416752A1 (en) * 1994-05-13 1995-11-16 Schloemann Siemag Ag Process and production plant for the production of hot wide strip

Also Published As

Publication number Publication date
DE19843200C1 (en) 1999-08-05
ATE230315T1 (en) 2003-01-15
RU2224605C2 (en) 2004-02-27
WO2000015362A1 (en) 2000-03-23
AU1149200A (en) 2000-04-03
DE59903924D1 (en) 2003-02-06
CN1317999A (en) 2001-10-17
CA2344423C (en) 2007-09-04
EP1112128A1 (en) 2001-07-04
ES2186438T3 (en) 2003-05-01
CN1142038C (en) 2004-03-17
CA2344423A1 (en) 2000-03-23
US6451136B1 (en) 2002-09-17

Similar Documents

Publication Publication Date Title
EP1469954B2 (en) Method for producing a hot rolled strip from austenitic rust-resistant steels
EP1951916B1 (en) Method and finishing train for hot-rolling starting material
CA1322479C (en) Method and apparatus for the manufacture of formable steel strip
EP2035587B1 (en) A method and a system for producing hot-rolled strip silicon steel based on thin slabs
EP0804300B1 (en) Process and device for producing a steel strip with the properties of a cold-rolled product
EP1305122B1 (en) Production method and installation for producing thin flat products
DE102008010062A1 (en) Process for hot rolling and heat treatment of a strip of steel
CA2332933A1 (en) Method and apparatus for producing martensite- or bainite-rich steel using steckel mill and controlled cooling
DE60014145T2 (en) METHOD FOR THE PRODUCTION OF CARBON STEEL STRIPS, ESPECIALLY FOR PACKAGING MATERIAL, AND SOFTWARE PRODUCED THEREFOR
EP0686702B1 (en) Process for producing hot wide strip
DE2262869B2 (en) Process for producing electrical steel sheet with a Goss texture
WO2011067315A1 (en) Hot rolling mill and method for hot rolling a metal strip or sheet
EP2991783A1 (en) Method for producing a metal strip
DE19600990C2 (en) Process for hot rolling steel strips
EP1112128B1 (en) Method and device for producing hot-rolled strips and plates
DE60015434T2 (en) Process for the production of deep-drawn sheets by direct casting of thin steel strips
DE19950502C1 (en) Hot rolled low alloy low carbon steel strip production, especially for deep drawing quality cold rolled strip manufacture, by rapidly cooling and then air cooling continuously cast strand before reheating and hot rolling
EP3206808B1 (en) Installation and method for producing heavy plate
EP1093866A2 (en) Method and device for improving the surface quality of a cast strand of a continuous casting plant
DE102020214427A1 (en) Method for producing a hot strip by means of a casting and rolling plant
DE2624258C2 (en) Process for annealing silicon steel slabs
DE2845531B2 (en) Method of treating a continuously cast stainless steel strand
DD207162B5 (en) Thermomechanical treatment process on continuous wire rod mills
DE3227368A1 (en) Process and apparatus for the production of hot wide strip, in particular from rust-resistant, acid-resistant and heat-resistant steels
JPH04311516A (en) Production of slab of high carbon 5% cr steel

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20010220

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

17Q First examination report despatched

Effective date: 20020628

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030102

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030102

REF Corresponds to:

Ref document number: 230315

Country of ref document: AT

Date of ref document: 20030115

Kind code of ref document: T

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: 20030102:NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20030104

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: GERMAN

REF Corresponds to:

Ref document number: 59903924

Country of ref document: DE

Date of ref document: 20030206

Kind code of ref document: P

ET Fr: translation filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030402

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030402

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2186438

Country of ref document: ES

Kind code of ref document: T3

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

Ref document number: 1112128E

Country of ref document: IE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030908

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030908

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030930

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030930

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030930

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20031003

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20090915

Year of fee payment: 11

REG Reference to a national code

Ref country code: NL

Ref legal event code: V1

Effective date: 20110401

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20110401

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FI

Payment date: 20120912

Year of fee payment: 14

Ref country code: GB

Payment date: 20120920

Year of fee payment: 14

Ref country code: SE

Payment date: 20120919

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20120926

Year of fee payment: 14

Ref country code: DE

Payment date: 20120921

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20121010

Year of fee payment: 14

Ref country code: BE

Payment date: 20120920

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20120926

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20120912

Year of fee payment: 14

BERE Be: lapsed

Owner name: *SMS DEMAG A.G.

Effective date: 20130930

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 59903924

Country of ref document: DE

REG Reference to a national code

Ref country code: SE

Ref legal event code: EUG

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130909

Ref country code: FI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130908

REG Reference to a national code

Ref country code: AT

Ref legal event code: MM01

Ref document number: 230315

Country of ref document: AT

Kind code of ref document: T

Effective date: 20130908

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20130908

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20140530

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130908

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130908

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130908

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140401

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 59903924

Country of ref document: DE

Effective date: 20140401

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20150507

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130909