EP1396549A1 - Process for manufacturing hot rolled pearlite-free steel strip and hot strip obtained thereby - Google Patents
Process for manufacturing hot rolled pearlite-free steel strip and hot strip obtained thereby Download PDFInfo
- Publication number
- EP1396549A1 EP1396549A1 EP02019314A EP02019314A EP1396549A1 EP 1396549 A1 EP1396549 A1 EP 1396549A1 EP 02019314 A EP02019314 A EP 02019314A EP 02019314 A EP02019314 A EP 02019314A EP 1396549 A1 EP1396549 A1 EP 1396549A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- hot
- temperature
- cooling
- hot strip
- strip
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
- C21D8/0215—Rapid solidification; Thin strip casting
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
Definitions
- High strength steels with good elongation characteristics and Processability are used in the field of vehicle construction, in general steel construction as well as in mechanical and apparatus engineering needed for the production of components that require high forces absorb and in their shape optimally to the each adjusted constructive requirements can be.
- a high-strength, good for these purposes malleable hot strip and a method to his Production are known from EP 0 295 500 B1.
- the for the production of the known hot strip used steel contains besides iron and the production-related unavoidable impurities (in% by weight) 0.15 to less than 0.3% C, 0.5 to 2.0% Si, 0.5 to 2.0% Mn.
- the steel 0.0005 to 0.0100 Ca or 0.005 to 0.050% rare earth metals.
- the known steel is according to EP 0 295 500 B1 in a Hot rolling stand with a hot rolling end temperature hot rolled, with a maximum of 50 ° C from the Ar3 temperature differs.
- the hot strip is on the following to the hot roll relay roller table controlled cooled, the EP 0 295 500 B1 two ways this controlled cooling pretends.
- the band will be at a relatively low level in a first stage Cooling speeds of 15 to 45 K / s and then in one second stage with a raised respectively Cooling cooled, which is between 35 to 80 K / s was.
- the cooling takes place three-stage with cooling rates in the first Stage 50 to 85 K / s, in the second stage 10 to 45 K / s and in the third stage was 35 to 80 K / s.
- the two Variants achieved reel temperatures were between 370 up to 520 ° C.
- Hot-rolled strip produced in this way has one formed from ferrite, retained austenite and bainite Structure.
- the formation of perlite and martensite is included largely suppressed to the formation of retained austenite not to hinder.
- the hot strip produced according to the known method Although has a high strength at high ductility. In practice, however, shows that its production is expensive. Also shows in the case of sudden Strains of high kinetic energies, like them for example, in motor vehicles in an accident typically occur that it is difficult to with the well-known steel the ever increasing Requirements for optimized crash behavior too fulfill. On top of that, conventional manufacturing the known hot strip is expensive.
- the Si and Mn content of the processed steel are included adjusted so that in the received hot strip one for the Achieving the TRIP effect sufficient amount Restaustenit is guaranteed.
- Manganese stabilizes the remaining after the controlled cooling in the steel Austenite.
- the presence of silicon supports on the one hand the formation of ferrite and also improves the Extensibility of the steel.
- the mechanical Properties improving effects causes the Limitation of the Si and Mn contents according to the invention also an improvement of the surface finish of the Hot strips. These effects are especially certain then one, if the sum of the contents of silicon and Manganese 1.5-2.5% by weight, in particular 1.8-2.3% by weight, is.
- TRIP steels contain retained austenite and consequently exhibit the effect of the so-called "TRANSformation Induced Plasticity. "It is essential according to the invention prescribed combination of the procedure over a casting mill and the presence of Ti and / or Nb.
- micro-alloying elements are used in the conventional production via slab casting in the slab excreted and go only partially in the warming of the Slab before hot rolling back into solution.
- these elements remain due to the between the Thin slab production and hot rolling usually in a tunnel furnace in passing heat supply however, until the beginning of hot rolling in solution.
- These Excretions improve the grain refinement of the finished Hotbands and contribute on the one hand to an increase in the Restaustenitanteils and on the other hand to a Stabilization of retained austenite against conversion into Martensite at.
- Produced according to the invention and Composite steel is therefore capable of higher Endure stress.
- the obtained thin slabs run with temperatures in the Range from 850 - 1050 ° C in a tunnel kiln.
- the inlet temperature is not less than 950 ° C to the formation of excreta at this stage to avoid the warm strip production.
- the thin slabs at 1000 - 1200 ° C in Flow annealed In the furnace, the thin slabs at 1000 - 1200 ° C in Flow annealed.
- the tunnel oven temperature is included preferably limited to the range of 1000 - 1050 ° C, to avoid excessive scale formation. To this Way is the lying at about 900 ° C temperature range safely bypassed using it in the invention Steel comes to a precipitation maximum. Instead the micro-alloying elements are kept in solution with the consequence that they are finer and finer in the finished product distributed more homogeneously.
- the residence time in the tunnel furnace on 10 to 60 minutes, preferably 15 to 35 minutes.
- the restriction causes the annealing time immediately increase the output of the Casting-rolling plant used according to the invention.
- the Formation of a fine-grained microstructure can also be assisted by the fact that, if the finish rolling is carried out in several passes, the deformation in the last pass of the hot rolling is at least 5%, preferably 15-25%.
- the through the various measures of the invention The achieved fine graininess not only contributes to Deformability, but together with the chemical Composition of processed steel also to Stabilization of the desired Restaustenitanteils at. So hinders the fine distribution of the individual
- the hot strip according to the invention produced hot strip existing phases also in a mechanical way the transformation of the retained austenite into Martensite.
- the hot strip according to the invention has due its not only one in terms of the retained austenite content high chemical but also a high geometric Stability on. This stability of the structure contributes to it in that still finished in produced from the hot strip Component residual austenite may be present.
- the post-warming controlled cooling has also a significant influence on the expression of the Microstructure and mechanical properties of the finished Hot strip. So can be targeted by the cooling the Shares of the individual phases and the strength and Affect elongation properties.
- a first Variant of the invention is the controlled cooling to this purpose, placing the hot strip in a first stage starting from the hot rolling end temperature with a Cooling speed of 70 to 500 K / s on a 600-750 ° C intermediate temperature is cooled, by placing the hot strip in a second stage for 2 to 13 seconds in air cools and by the hot strip then in a third stage with a 30 to 200 K / s amounting cooling speed on a reel temperature is cooled, which is 300 - 530 ° C.
- the highest possible Cooling rate in the first stage of cooling has a positive effect on the hot strip obtained contained Austenitmenge from. Therefore, after one preferred embodiment of this variant of the controlled Cooling the cooling rate in the first stage of the Cooling at least 150 K / s, preferably 300 K / s.
- the duration of the second stage of cooling may be preferred for this purpose be limited to 4 to 8 seconds. Subsequently, will in the third stage the accelerated cooling continued to the formation of perlite and grain growth to suppress.
- Another variant of the invention provides that the controlled cooling takes place in that the hot strip with a cooling rate of 10 to 70 K / s continuously from the hot rolling end temperature to the Reel temperature is cooled. Also in this way lets a hot strip with the invention sought after Create microstructure.
- the cools Hot strip after reeling in the coil continues from.
- the hot strip accelerates after a rest period in the coil is cooled.
- the desired division of the individual phase components adjusts when the accelerated cooling of the coil after a rest period ranging from 2 to 30 starts.
- the cooling by applying the Accelerate coils with a cooling fluid.
- a liquid such as water, or an air stream be used.
- the hot strip produced according to the invention has in each case at least three of the structural components ferrite, bainite, Retained austenite or martensite.
- the sum of the Content of martensite and retained austenite at least 8% be.
- As low as possible martensite contents are sought to reduce carbon loss to the detriment of the To avoid residual austenite. Accordingly sees the Invention that the carbon content of the retained austenite more than 1%. This carbon content leaves For example, determine by X-ray.
- produced hot strip is suitable in special way for use in vehicle construction, in Steel construction, in general machine and apparatus construction as well in shipbuilding.
- the invention is based on Embodiments explained in more detail.
- the steel melts S1, S2, S3 are in a casting-rolling plant to thin slabs with an average thickness 55 mm has been cast in a continuous the casting subsequent process in a tunnel kiln in which they are at average Temperatures of 1050 ° C in the course of an annealing have been subjected. After leaving the oven, the Thin slabs happen a scale washer in which their Surface by applying one under more than 300 bar of sprayed cleaning liquid in the flow has been freed from the tinder.
- the thus cleaned thin slabs are then in one multistage hot roll stand arrived, in which they at a hot rolling end temperature ET in several passes too in each case, a hot strip with a thickness d finished hot rolled have been.
- the hot strip thicknesses d are in Table 2.
- Table 4 shows the relevant process parameters and the thickness d of the hot strips W5 to W10.
- Table 5 contains the corresponding information on the respective tensile strength Rm, uniform elongation Ag, elongation A80 and elongation A5 as well as the respective product of Rm * A5 and Rm * A80.
Abstract
Description
Hochfeste Stähle mit guten Dehnungskennwerten und Verarbeitbarkeit werden im Bereich des Fahrzeugbaus, im allgemeinen Stahlbau sowie im Maschinen- und Apparatebau zur Herstellung von Bauteilen benötigt, die hohe Kräfte aufnehmen und in ihrer Formgebung optimal an die sich jeweils stellenden konstruktiven Anforderungen angepasst werden können.High strength steels with good elongation characteristics and Processability are used in the field of vehicle construction, in general steel construction as well as in mechanical and apparatus engineering needed for the production of components that require high forces absorb and in their shape optimally to the each adjusted constructive requirements can be.
Ein für diese Einsatzzwecke bestimmtes hochfestes, gut verformbares Warmband und ein Verfahren zu seiner Herstellung sind aus der EP 0 295 500 B1 bekannt. Der für die Erzeugung des bekannten Warmbands verwendete Stahl enthält neben Eisen und den herstellungsbedingt unvermeidbaren Verunreinigungen (in Gew.-%) 0,15 bis weniger als 0,3 % C, 0,5 bis 2,0 % Si, 0,5 bis 2,0 % Mn. Zusätzlich können in dem Stahl 0,0005 bis 0,0100 Ca oder 0,005 bis 0,050 % Seltenerdmetalle enthalten sein.A high-strength, good for these purposes malleable hot strip and a method to his Production are known from EP 0 295 500 B1. The for the production of the known hot strip used steel contains besides iron and the production-related unavoidable impurities (in% by weight) 0.15 to less than 0.3% C, 0.5 to 2.0% Si, 0.5 to 2.0% Mn. In addition, in the steel, 0.0005 to 0.0100 Ca or 0.005 to 0.050% rare earth metals.
Der bekannte Stahl wird gemäß der EP 0 295 500 B1 in einer Warmwalzstaffel mit einer Warmwalzendtemperatur warmgewalzt, die mit maximal 50 °C von der Ar3-Temperatur abweicht. Im Anschluss an das Warmwalzen wird das Warmband auf dem sich an die Warmwalzstaffel anschließenden Rollgang gesteuert abgekühlt, wobei die EP 0 295 500 B1 zwei Wege dieser gesteuerten Abkühlung vorgibt. Auf dem ersten Weg wird das Band in einer ersten Stufe bei relativ niedrigen Abkühlgeschwindigkeiten von 15 bis 45 K/s und dann in einer zweiten Stufe mit einer jeweils erhöhten Abkühlgeschwindigkeit gekühlt, die zwischen 35 bis 80 K/s lag. Bei der anderen Variante erfolgt die Abkühlung dreistufig mit Abkühlgeschwindigkeiten, die in der ersten Stufe 50 bis 85 K/s, in der zweiten Stufe 10 bis 45 K/s und in der dritten Stufe 35 bis 80 K/s betrug. Die bei beiden Varianten erreichten Haspeltemperaturen lagen zwischen 370 bis 520 °C.The known steel is according to EP 0 295 500 B1 in a Hot rolling stand with a hot rolling end temperature hot rolled, with a maximum of 50 ° C from the Ar3 temperature differs. Following hot rolling, the hot strip is on the following to the hot roll relay roller table controlled cooled, the EP 0 295 500 B1 two ways this controlled cooling pretends. On the first way The band will be at a relatively low level in a first stage Cooling speeds of 15 to 45 K / s and then in one second stage with a raised respectively Cooling cooled, which is between 35 to 80 K / s was. In the other variant, the cooling takes place three-stage with cooling rates in the first Stage 50 to 85 K / s, in the second stage 10 to 45 K / s and in the third stage was 35 to 80 K / s. The two Variants achieved reel temperatures were between 370 up to 520 ° C.
Zusätzlich zu der mehrstufigen Abkühlung wird gemäß dem aus der EP 0 295 500 B1 bekannten Verfahren eine Abkühlung des Warmbandes im Coil durchgeführt. Dabei wird das Band mit einer Abkühlgeschwindigkeit von mindestens 30 °C/h auf eine unter 200 °C liegende Temperatur beschleunigt abgekühlt.In addition to the multi-stage cooling is in accordance with the EP 0 295 500 B1 known method cooling the Hot strip performed in the coil. This is the tape with a cooling rate of at least 30 ° C / h on a Temperature below 200 ° C accelerated cooled.
Warmband, das in dieser Weise hergestellt worden ist, besitzt eine aus Ferrit, Restaustenit und Bainit gebildete Struktur. Die Bildung von Perlit und Martensit ist dabei weitestgehend unterdrückt, um die Bildung von Restaustenit nicht zu behindern.Hot-rolled strip produced in this way has one formed from ferrite, retained austenite and bainite Structure. The formation of perlite and martensite is included largely suppressed to the formation of retained austenite not to hinder.
Das gemäß dem bekannten Verfahren hergestellte Warmband weist zwar eine hohe Festigkeit bei hoher Dehnbarkeit auf. In der Praxis zeigt sich jedoch, dass seine Herstellung aufwändig ist. Auch zeigt sich im Fall plötzlicher Belastungen durch hohe kinetische Energien, wie sie beispielsweise bei Kraftfahrzeugen bei einem Unfall typischerweise auftreten, dass es nur schwer möglich ist, mit dem bekannten Stahl die immer weiter steigenden Anforderungen an ein optimiertes Crash-Verhalten zu erfüllen. Hinzu kommt, dass die konventionelle Fertigung des bekannten Warmbandes aufwändig ist. The hot strip produced according to the known method Although has a high strength at high ductility. In practice, however, shows that its production is expensive. Also shows in the case of sudden Strains of high kinetic energies, like them for example, in motor vehicles in an accident typically occur that it is difficult to with the well-known steel the ever increasing Requirements for optimized crash behavior too fulfill. On top of that, conventional manufacturing the known hot strip is expensive.
Die der Erfindung zu Grunde liegende Aufgabe bestand daher darin, ein kostengünstig und praxisgerecht durchführbares Verfahren anzugeben, welches zuverlässig die Herstellung von hinsichtlich ihrer Festigkeits- und Verformungseigenschaften optimierten Warmbändern ermöglicht.The task underlying the invention was therefore therein, a cost-effective and practical feasible Specify method, which reliably the production in terms of their strength and Deformation properties of optimized hot strips allows.
Diese Aufgabe wird erfindungsgemäß durch ein Verfahren zum Herstellen eines warmgewalzten Stahlbands gelöst, das perlitfrei ist, TRIP-Eigenschaften besitzt und eine Zugfestigkeit von mindestens 600 MPa aufweist. Erfindungsgemäß wird dieses Warmband in einem kontinuierlich ablaufenden Arbeitsprozess erzeugt, bei dem mindestens folgende Arbeitsschritte durchgeführt werden:
- Vergießen einer Stahlschmelze, die neben Eisen und unvermeidbaren Verunreinigungen (in Gew.-%) 0,06 - 0,3 % C, 0,1 - 3,0 % Si, 0,3 - 1,1 % Mn, wobei die Summe aus den Gehalten an Si und Mn 1,5 - 3,5 % beträgt, mindestens eines der Elemente Ti oder Nb in Gehalten von jeweils 0,005 - 0,15 %, sowie wahlweise einzeln oder in Kombination max. 0,8 % Cr, max. 0,8 % Mo, max. 1 % Cu und max. 1 % Ni, enthält, zu Dünnbrammen,
- Glühen der mit einer 850 bis 1050 °C betragenden Einlauftemperatur in einen Glühofen einlaufenden Dünnbrammen bei Glühtemperaturen von 1000 bis 1200 °C für eine Glühdauer von 10 bis 60 Minuten,
- Entzundern der Dünnbrammen in einem Zunderwäscher unter einem Abspritzdruck der zum Entzundern eingesetzten Flüssigkeit von mindestens 300 bar,
- Fertigwarmwalzen der Dünnbrammen zu einem Warmband bei Warmwalzendtemperaturen, die im Bereich von 750 bis 1000 °C liegen,
- gesteuertes Abkühlen des erhaltenen Warmbands auf eine Haspeltemperatur,
- Haspeln des Warmbands.
- Casting a molten steel, in addition to iron and unavoidable impurities (in wt .-%) 0.06 - 0.3% C, 0.1 - 3.0% Si, 0.3 - 1.1% Mn, the sum from the contents of Si and Mn is 1.5-3.5%, at least one of the elements Ti or Nb in contents of 0.005-0.15% each, and optionally individually or in combination max. 0.8% Cr, max. 0.8% Mo, max. 1% Cu and max. 1% Ni, contains, to thin slabs,
- Annealing the inlet temperature, which amounts to 850 to 1050 ° C., into thin slabs entering an annealing furnace at annealing temperatures of 1000 to 1200 ° C. for an annealing time of 10 to 60 minutes,
- Descaling the thin slabs in a scale washer under a spray pressure of the liquid used for descaling of at least 300 bar,
- Finish hot rolling of the thin slabs to a hot strip at hot rolling end temperatures ranging from 750 to 1000 ° C,
- controlled cooling of the resulting hot strip to a reel temperature,
- Coiling the hot strip.
Gemäß der Erfindung wird in einem kontinuierlich ablaufenden Verfahren, wie es typisch auf einer Gießwalzanlage durchführbar ist, ein TRIP-Eigenschaften besitzendes Warmband erzeugt, welches aufgrund einer optimierten Abstimmung seiner Legierungsgehalte und der Art und Weise seiner Herstellung eine Kombination von Verformungseigenschaften und Festigkeitswerten aufweist, die einerseits seine Verarbeitung vereinfacht und andererseits zu einem verbesserten Kraftaufnahmevermögen im Fall plötzlicher Belastung durch hohe Verformungsenergien beiträgt.According to the invention is in a continuous ongoing procedures, as is typical on one Cast rolling mill is feasible, a TRIP properties owning hot strip produced, which due to a optimized tuning of its alloy contents and type and way of making it a combination of Having deformation properties and strength values, on the one hand simplifies its processing and on the other hand to an improved power absorption in the Fall of sudden stress due to high deformation energies contributes.
Der Si- und Mn-Gehalt des verarbeiteten Stahles sind dabei so abgestimmt, dass im erhaltenen Warmband eine für die Erzielung des TRIP-Effekts ausreichende Menge an Restaustenit gewährleistet ist. Mangan stabilisiert den nach der gesteuerten Abkühlung im Stahl verbleibenden Restaustenit. Die Anwesenheit von Silizium unterstützt einerseits die Bildung von Ferrit und verbessert zudem die Dehnbarkeit des Stahls. Andererseits wirkt sich der Silizium-Gehalt günstig im Hinblick auf die Anreicherung des im Zuge der Warmbanderzeugung nicht umgewandelten Austenits mit Kohlenstoff aus. Neben den die mechanischen Eigenschaften verbessernden Effekten bewirkt die erfindungsgemäße Beschränkung der Si- und Mn-Gehalte auch eine Verbesserung der Oberflächenbeschaffenheit der Warmbänder. Besonders sicher stellen sich diese Wirkungen dann ein, wenn die Summe aus den Gehalten an Silizium und Mangan 1,5 - 2,5 Gew.-%, insbesondere 1,8 - 2,3 Gew.-%, beträgt.The Si and Mn content of the processed steel are included adjusted so that in the received hot strip one for the Achieving the TRIP effect sufficient amount Restaustenit is guaranteed. Manganese stabilizes the remaining after the controlled cooling in the steel Austenite. The presence of silicon supports on the one hand, the formation of ferrite and also improves the Extensibility of the steel. On the other hand, the affects Silicon content favorable in terms of enrichment of the not converted in the course of hot strip production Austenite with carbon out. In addition to the mechanical Properties improving effects causes the Limitation of the Si and Mn contents according to the invention also an improvement of the surface finish of the Hot strips. These effects are especially certain then one, if the sum of the contents of silicon and Manganese 1.5-2.5% by weight, in particular 1.8-2.3% by weight, is.
Wesentlicher Bestandteil der erfindungsgemäß verarbeiteten Legierung ist neben den Gehalten an Silizium und Mangan der Gehalt an mindestens einem der Elemente Niob und Titan. TRIP-Stähle enthalten Restaustenit und weisen infolgedessen den Effekt der sogenannten "TRansformation Induced Plasticity" auf. Wesentlich ist dabei die erfindungsgemäß vorgeschriebene Kombination aus der Verfahrensführung über eine Gießwalzanlage und dem Vorhandensein von Ti und/oder Nb.Essential part of the invention processed Alloy is in addition to the levels of silicon and manganese the Content of at least one of the elements niobium and titanium. TRIP steels contain retained austenite and consequently exhibit the effect of the so-called "TRANSformation Induced Plasticity. "It is essential according to the invention prescribed combination of the procedure over a casting mill and the presence of Ti and / or Nb.
Diese Mikrolegierungselemente werden bei der konventionellen Erzeugung über Brammenguss in der Bramme ausgeschieden und gehen nur teilweise bei der Erwärmung der Bramme vor dem Warmwalzen wieder in Lösung. Bei der erfindungsgemäß vorgeschriebenen Erzeugung einer Dünnbramme bleiben diese Elemente bedingt durch die zwischen der Dünnbrammenerzeugung und dem Warmwalzen in der Regel in einem Tunnelofen im Durchlauf erfolgende Wärmezufuhr dagegen bis zum Beginn des Warmwalzens in Lösung. Diese Ausscheidungen verbessern die Kornfeinung des fertigen Warmbands und tragen einerseits zu einer Erhöhung des Restaustenitanteils und andererseits zu einer Stabilisierung des Restaustenits gegen eine Umwandlung in Martensit bei. Erfindungsgemäß erzeugter und zusammengesetzter Stahl ist daher in der Lage, höhere Belastungen zu ertragen. Diese Eigenschaft macht ihn besonders geeignet für die Herstellung von so genannten "crash-relevanten" Bauteilen, die beispielsweise bei einem Unfall plötzlich hohen Beanspruchungen ausgesetzt sind. Durch die gegebenenfalls kombinierte, notwendige Anwesenheit von Niob und/oder Titan in Gehalten von jeweils bis zu 0,15 Gew.-% werden so in Kombination mit dem erfindungsgemäß eingeschlagenen Verfahrensweg die Verformbarkeit des Warmbands selbst und die Verfestigungsprozesse im Fall einer Verformung eines aus dem erfindungsgemäß erzeugten Warmband hergestellten Bauteils gezielt verbessert.These micro-alloying elements are used in the conventional production via slab casting in the slab excreted and go only partially in the warming of the Slab before hot rolling back into solution. In the According to the invention prescribed generation of a thin slab these elements remain due to the between the Thin slab production and hot rolling usually in a tunnel furnace in passing heat supply however, until the beginning of hot rolling in solution. These Excretions improve the grain refinement of the finished Hotbands and contribute on the one hand to an increase in the Restaustenitanteils and on the other hand to a Stabilization of retained austenite against conversion into Martensite at. Produced according to the invention and Composite steel is therefore capable of higher Endure stress. This property makes him especially suitable for the production of so-called "crash-relevant" components, for example, in a Accident suddenly exposed to high stresses. By possibly combined, necessary Presence of niobium and / or titanium in levels of each up to 0.15 wt .-% are so in combination with the According to the invention taken process path the Deformability of the hot strip itself and the Solidification processes in the case of deformation of a produced according to the invention produced hot strip Component specifically improved.
Nach dem Vergießen des erfindungsgemäß verwendeten Stahls zu Dünnbrammen, deren Dicke typisch 40 bis 70 mm beträgt, laufen die erhaltenen Dünnbrammen mit Temperaturen, die im Bereich von 850 - 1050 °C in einen Tunnelofen ein. Bevorzugt beträgt die Einlauftemperatur nicht weniger als 950 °C, um die Bildung von Ausscheidungen in diesem Stadium der Warmbanderzeugung zu vermeiden.After casting the steel used in the invention to thin slabs whose thickness is typically 40 to 70 mm, The obtained thin slabs run with temperatures in the Range from 850 - 1050 ° C in a tunnel kiln. Preferably, the inlet temperature is not less than 950 ° C to the formation of excreta at this stage to avoid the warm strip production.
In dem Ofen werden die Dünnbrammen bei 1000 - 1200 °C im Durchlauf geglüht. Die Tunnelofentemperatur ist dabei vorzugsweise auf den Bereich von 1000 - 1050 °C beschränkt, um eine übermäßige Zunderbildung zu vermeiden. Auf diese Weise wird der bei ca. 900 °C liegende Temperaturbereich sicher umgangen, bei dem es im erfindungsgemäß verwendeten Stahl zu einem Ausscheidungsmaximum kommt. Stattdessen werden die Mikrolegierungselemente in Lösung gehalten mit der Folge, dass sie im fertigen Produkt feiner und homogener verteilt vorliegen.In the furnace, the thin slabs at 1000 - 1200 ° C in Flow annealed. The tunnel oven temperature is included preferably limited to the range of 1000 - 1050 ° C, to avoid excessive scale formation. To this Way is the lying at about 900 ° C temperature range safely bypassed using it in the invention Steel comes to a precipitation maximum. Instead the micro-alloying elements are kept in solution with the consequence that they are finer and finer in the finished product distributed more homogeneously.
Zum selben Zweck ist die Verweilzeit im Tunnelofen auf 10 - 60 Minuten, bevorzugt 15 - 35 Minuten, beschränkt. Darüber hinaus bewirkt die Beschränkung der Glühdauer unmittelbar eine Erhöhung der Ausbringung der erfindungsgemäß eingesetzten Gieß-Walz-Anlage. For the same purpose, the residence time in the tunnel furnace on 10 to 60 minutes, preferably 15 to 35 minutes. In addition, the restriction causes the annealing time immediately increase the output of the Casting-rolling plant used according to the invention.
Auch wenn es bei der durch die Erfindung vorgegebenen Vorgehensweise insgesamt zur Entstehung geringerer Zundermengen auf den Oberflächen der verarbeiteten Dünnbrammen kommt, werden die Dünnbrammen nach dem Glühen in einem Zunderwäscher gezielt entzundert. Der Druck, mit dem dabei die Reinigungsflüssigkeit, in der Regel Wasser, auf die Brammen gegeben wird, beträgt erfindungsgemäß mindestens 300 bar, um eine weitestgehende Entfernung aller auf den Oberflächen der Bramme vorhandenen Rückstände zu erreichen. Besonders die auf den Brammen vorhandene Menge an Fayalit, welches andernfalls im weiteren Prozess die Bildung von unerwünschtem Rotzunder verursachen kann, wird auf diese Weise weitestgehend entfernt.Even if it is given by the invention Overall approach to the emergence of lesser Scale amounts on the surfaces of the processed Thin slab comes, the thin slabs become after annealing descaled in a scale washer. The pressure, with while doing the cleaning liquid, usually water, is placed on the slabs is according to the invention at least 300 bar, to a distance as far as possible Residues on the surfaces of the slab too to reach. Especially the amount present on the slabs at Fayalit, which otherwise in the further process the Formation of unwanted Rotzunder can cause far removed in this way.
In der anschließend durchlaufenen Fertigwalzstaffel werden aus den Dünnbrammen bei Warmwalzendtemperaturen von 750 bis 1000 °C Warmbänder gewalzt, deren Dicke typischerweise 0,8 - 10 mm beträgt. Durch die innerhalb des vorgegebenen Temperaturbereichs jeweils konkret gewählte Endtemperatur lässt sich die Feinheit und die Zusammensetzung der Struktur der erhaltenen Warmbänder beeinflussen. So kann schon dadurch, dass das Fertigwalzen unterhalb der Ar3-Temperatur beendet wird, eine verfeinerte Körnung erreicht werden. Über der Ar3-Temperatur liegende Warmwalzendtemperaturen können eingestellt werden, wenn größere Mengen an Restaustenit gebildet werden sollen.In the subsequently completed finish rolling mill from the thin slabs at hot rolling end temperatures of 750 to Rolled 1000 ° C hot strips whose thickness is typically 0.8-10 mm. By within the given Temperature range in each case specifically selected final temperature can the fineness and the composition of the Structure of the obtained hot strip influence. So can already by the fact that the finish rolling below the Ar3 temperature finished, achieved a refined grain become. Above the Ar3 temperature Hot rolling temperatures can be adjusted if larger amounts of retained austenite are to be formed.
Im Hinblick auf die Feinheit der Struktur des erhaltenen Warmbandes hat es sich darüber hinaus als günstig erwiesen, wenn der während des Fertigwarmwalzens erzielte Gesamtumformgrad ϕges 1,8 - 3,7 beträgt. Auf diese Weise ist eine ausreichende Zerstörung des Gussgefüges der Brammen sichergestellt und es wird eine optimierte Feinkörnigkeit des erhalten Warmbandes erzielt. Dies ist insbesondere dann der Fall, wenn der über das Warmwalzen erzielte Umformgrad ϕges mindestens 2,5 beträgt. Unterstützt werden kann die Ausbildung eines feinkörnigen Gefüges zudem dadurch, dass, wenn das Fertigwalzen in mehreren Stichen durchgeführt wird, die Verformung im letzten Stich des Warmwalzens mindestens 5 %, bevorzugt 15 - 25 %, beträgt.In view of the fineness of the structure of the resulting hot strip, it has also proved to be favorable if the Gesamtumformgrad φ ges achieved during the final hot rolling is 1.8-3.7. In this way, a sufficient destruction of the cast structure of the slabs is ensured and it is achieved an optimized fine grain of the hot strip obtained. This is the case in particular when the degree of deformation φ ges achieved via hot rolling is at least 2.5. The formation of a fine-grained microstructure can also be assisted by the fact that, if the finish rolling is carried out in several passes, the deformation in the last pass of the hot rolling is at least 5%, preferably 15-25%.
Die durch die verschiedenen Maßnahmen der erfindungsgemäßen Vorgehensweise erreichte Feinkörnigkeit trägt nicht nur zur Verformbarkeit, sondern gemeinsam mit der chemischen Zusammensetzung des verarbeiteten Stahls auch zur Stabilisierung des erwünschten Restaustenitanteils bei. So behindert die feine Verteilung der einzelnen im erfindungsgemäß erzeugten Warmband vorhandenen Phasen auch auf mechanische Weise die Umwandlung des Restaustenits in Martensit. Das erfindungsgemäße Warmband weist infolge dessen in Bezug auf den Restaustenitanteil nicht nur eine hohe chemische, sondern auch eine hohe geometrische Stabilität auf. Diese Stabilität des Gefüges trägt dazu bei, dass noch im aus dem Warmband erzeugten fertigen Bauteil Restaustenit vorliegen kann.The through the various measures of the invention The achieved fine graininess not only contributes to Deformability, but together with the chemical Composition of processed steel also to Stabilization of the desired Restaustenitanteils at. So hinders the fine distribution of the individual According to the invention produced hot strip existing phases also in a mechanical way the transformation of the retained austenite into Martensite. The hot strip according to the invention has due its not only one in terms of the retained austenite content high chemical but also a high geometric Stability on. This stability of the structure contributes to it in that still finished in produced from the hot strip Component residual austenite may be present.
Die nach dem Warmwalzen erfolgende gesteuerte Abkühlung hat ebenfalls wesentlichen Einfluss auf die Ausprägung der Gefügestruktur und mechanischen Eigenschaften des fertigen Warmbands. So lassen sich durch die Abkühlung gezielt die Anteile der einzelnen Phasen sowie die Festigkeits- und Dehnungseigenschaften beeinflussen. Gemäß einer ersten Variante der Erfindung erfolgt die gesteuerte Abkühlung zu diesem Zweck, indem das Warmband in einer ersten Stufe ausgehend von der Warmwalzendtemperatur mit einer Abkühlgeschwindigkeit von 70 bis 500 K/s auf eine 600 - 750 °C betragende Zwischentemperatur gekühlt wird, indem das Warmband anschließend in einer zweiten Stufe für 2 bis 13 Sekunden an Luft abkühlt und indem das Warmband daraufhin in einer dritten Stufe mit einer 30 bis 200 K/s betragenden Abkühlgeschwindigkeit auf eine Haspeltemperatur gekühlt wird, die 300 - 530 °C beträgt. Eine möglichst hohe Abkühlgeschwindigkeit in der ersten Stufe der Abkühlung wirkt sich dabei positiv auf die im erhaltenen Warmband enthaltene Restaustenitmenge aus. Daher beträgt nach einer bevorzugten Ausführungsform dieser Variante der gesteuerten Abkühlung die Abkühlgeschwindigkeit in der ersten Stufe der Abkühlung mindestens 150 K/s, bevorzugt 300 K/s.The post-warming controlled cooling has also a significant influence on the expression of the Microstructure and mechanical properties of the finished Hot strip. So can be targeted by the cooling the Shares of the individual phases and the strength and Affect elongation properties. According to a first Variant of the invention is the controlled cooling to this purpose, placing the hot strip in a first stage starting from the hot rolling end temperature with a Cooling speed of 70 to 500 K / s on a 600-750 ° C intermediate temperature is cooled, by placing the hot strip in a second stage for 2 to 13 seconds in air cools and by the hot strip then in a third stage with a 30 to 200 K / s amounting cooling speed on a reel temperature is cooled, which is 300 - 530 ° C. The highest possible Cooling rate in the first stage of cooling has a positive effect on the hot strip obtained contained Austenitmenge from. Therefore, after one preferred embodiment of this variant of the controlled Cooling the cooling rate in the first stage of the Cooling at least 150 K / s, preferably 300 K / s.
Nach der ersten Phase der schnellen Abkühlung erfolgt in der zweiten Phase eine Kühlpause, um die Bildung von größeren Mengen an Ferrit und die Anreicherung des Restaustenits mit Kohlenstoff zu ermöglichen. Die Dauer der zweiten Stufe der Abkühlung kann zu diesem Zweck bevorzugt auf 4 bis 8 Sekunden beschränkt werden. Anschließend wird in der dritten Stufe die beschleunigte Abkühlung fortgesetzt, um die Bildung von Perlit und das Kornwachstum zu unterdrücken.After the first phase of rapid cooling takes place in the second phase a cooling break to the formation of larger amounts of ferrite and the accumulation of To allow residual austenite with carbon. The duration of the second stage of cooling may be preferred for this purpose be limited to 4 to 8 seconds. Subsequently, will in the third stage the accelerated cooling continued to the formation of perlite and grain growth to suppress.
Eine andere Variante der Erfindung sieht vor, dass die gesteuerte Abkühlung dadurch erfolgt, dass das Warmband mit einer Abkühlgeschwindigkeit von 10 bis 70 K/s kontinuierlich von der Warmwalzendtemperatur auf die Haspeltemperatur gekühlt wird. Auch auf diese Weise lässt sich ein Warmband mit der erfindungsgemäß angestrebten Gefügestruktur erzeugen.Another variant of the invention provides that the controlled cooling takes place in that the hot strip with a cooling rate of 10 to 70 K / s continuously from the hot rolling end temperature to the Reel temperature is cooled. Also in this way lets a hot strip with the invention sought after Create microstructure.
Schließlich ist es möglich, die Abkühlung so zu steuern, dass das Warmband in einer ersten Stufe innerhalb von 1 - 7 Sekunden auf eine Temperatur abgekühlt wird, die etwa 80 °C über der Haspeltemperatur liegt, und dass das Warmband anschließend an Luft auf die Haspeltemperatur abkühlt, die im Bereich von 300 bis 530 °C liegt. Bei dieser Variante der gesteuerten Abkühlung erfolgt im ersten Schritt eine besonders schnelle Abkühlung mit der Folge, dass sich ein besonders feines Gefüge mit hohem Restaustenitanteil und hoher Festigkeit einstellt.Finally, it is possible to control the cooling so that the hot strip is in a first stage within 1 to 7 seconds to a temperature that is about 80 ° C is above the reel temperature, and that the Hot strip then in air on the reel temperature cools, which is in the range of 300 to 530 ° C. at This variant of the controlled cooling takes place in the first Step a particularly fast cooling with the consequence that a particularly fine structure with high Restaustenitanteil and high strength sets.
Unabhängig, welche der voranstehend erläuterten Varianten der gesteuerten Abkühlung eingesetzt werden, kühlt das Warmband nach dem Haspeln im Coil weiter ab. Damit es dabei nicht zur Bildung von unerwünscht großen Mengen an Bainit auf Kosten des Restaustenits kommt, ist es günstig, wenn das Warmband nach einer Ruhezeit im Coil beschleunigt abgekühlt wird. Es hat sich gezeigt, dass sich die gewünschte Aufteilung der einzelnen Phasen-Anteile einstellt, wenn die beschleunigte Kühlung des Coils nach einer im Bereich von 2 bis 30 liegenden Ruhezeit beginnt. Dabei lässt sich die Abkühlung durch Beaufschlagung des Coils mit einem Kühlfluid beschleunigen. Abhängig von den jeweils erforderlichen Abkühlgeschwindigkeiten kann dazu eine Flüssigkeit, beispielsweise Wasser, oder ein Luftstrom eingesetzt werden.Independently, which of the above-explained variants the controlled cooling are used, the cools Hot strip after reeling in the coil continues from. To do it not to the formation of undesirably large amounts of bainite comes at the expense of residual austenite, it is favorable if The hot strip accelerates after a rest period in the coil is cooled. It has been shown that the desired division of the individual phase components adjusts when the accelerated cooling of the coil after a rest period ranging from 2 to 30 starts. In this case, the cooling by applying the Accelerate coils with a cooling fluid. Depending on the each required cooling rates can do so a liquid, such as water, or an air stream be used.
Das erfindungsgemäß erzeugte Warmband weist jeweils mindestens drei der Gefügebestandteile Ferrit, Bainit, Restaustenit oder Martensit auf. Dabei sollte die Summe der Gehalte an Martensit und Restaustenit mindestens 8 % betragen. Möglichst geringe Martensitgehalte sind angestrebt, um einen Kohlenstoffverlust zu Ungunsten des Restaustenits zu vermeiden. Dementsprechend sieht die Erfindung vor, dass der Kohlenstoffgehalt des Restaustenits mehr als 1 % betragen soll. Dieser Kohlenstoffgehalt lässt sich beispielsweise röntgenographisch ermitteln. The hot strip produced according to the invention has in each case at least three of the structural components ferrite, bainite, Retained austenite or martensite. The sum of the Content of martensite and retained austenite at least 8% be. As low as possible martensite contents are sought to reduce carbon loss to the detriment of the To avoid residual austenite. Accordingly sees the Invention that the carbon content of the retained austenite more than 1%. This carbon content leaves For example, determine by X-ray.
Durch die erfindungsgemäße Weise der Herstellung lassen sich Warmbänder erzeugen, bei denen das Produkt RM*A5 aus Zugfestigkeit Rm und Bruchdehnung A5 mindestens 19.000 MPa*% und das Produkt Rm*A80 aus Zugfestigkeit Rm und Bruchdehnung A80 mindestens 16.000 MPa*%, insbesondere 17.000 MPa*%, beträgt.Leave the method of manufacture according to the invention Produce hot strips where the product RM * A5 is made Tensile strength Rm and elongation at break A5 at least 19,000 MPa *% and the product Rm * A80 from tensile strength Rm and elongation at break A80 at least 16,000 MPa *%, in particular 17,000 MPa *%.
Erfindungsgemäß erzeugtes Warmband eignet sich in besonderer Weise zur Verwendung im Fahrzeugbau, im Stahlbau, im allgemeinen Maschinen- und Apparatebau sowie im Schiffsbau.According to the invention produced hot strip is suitable in special way for use in vehicle construction, in Steel construction, in general machine and apparatus construction as well in shipbuilding.
Nachfolgend wird die Erfindung anhand von Ausführungsbeispielen näher erläutert.The invention is based on Embodiments explained in more detail.
Es sind Stahlschmelzen S1, S2 und S3 erschmolzen worden, deren Zusammensetzungen in Tabelle 1 angegeben sind.Steel melts S1, S2 and S3 have been smelted, their compositions are given in Table 1.
Die Stahlschmelzen S1, S2, S3 sind in einer Gieß-Walz-Anlage zu Dünnbrammen mit einer Dicke von durchschnittlich 55 mm vergossen worden, die in einem sich kontinuierlich an das Vergießen anschließenden Vorgang in einen Tunnelofen eingelaufen sind, in dem sie bei durchschnittlichen Temperaturen von 1050 °C im Durchlauf einer Glühung unterzogen worden sind. Nach Verlassen des Ofens haben die Dünnbrammen einen Zunderwäscher passiert, in dem ihre Oberfläche durch Beaufschlagung mit einer unter mehr als 300 bar abgespritzten Reinigungsflüssigkeit im Durchlauf vom Zunder befreit worden ist.The steel melts S1, S2, S3 are in a casting-rolling plant to thin slabs with an average thickness 55 mm has been cast in a continuous the casting subsequent process in a tunnel kiln in which they are at average Temperatures of 1050 ° C in the course of an annealing have been subjected. After leaving the oven, the Thin slabs happen a scale washer in which their Surface by applying one under more than 300 bar of sprayed cleaning liquid in the flow has been freed from the tinder.
Die derart gesäuberten Dünnbrammen sind dann in eine mehrgerüstige Warmwalzstaffel eingelaufen, in der sie bei einer Warmwalzendtemperatur ET in mehreren Stichen zu jeweils einem Warmband mit einer Dicke d fertigwarmgewalzt worden sind.The thus cleaned thin slabs are then in one multistage hot roll stand arrived, in which they at a hot rolling end temperature ET in several passes too in each case, a hot strip with a thickness d finished hot rolled have been.
Anschließend sind die aus den Schmelzen S1 und S2 erzeugten Warmbänder W1 - W4 in drei Stufen abgekühlt worden. In der ersten Stufe dieser Abkühlung sind die betreffenden Warmbänder jeweils mit einer Abkühlgeschwindigkeit Ag1 auf eine Zwischentemperatur ZT1 gekühlt worden. Daran schloss sich für eine Zeitdauer t2 eine Abkühlung an Luft an, auf die wiederum die dritte Abkühlstufe folgte, in der die Bänder mit einer Abkühlgeschwindigkeit Ag2 auf eine Temperatur ZT2 gekühlt worden sind. Auf dem zwischen dem Ende der Kühleinrichtung bis zur Haspeleinrichtung zurückgelegten Weg sind die Warmbänder dann auf die Temperatur HT angekühlt, mit der sie gehaspelt worden sind.Subsequently, those generated from the melts S1 and S2 Hot strips W1 - W4 have been cooled in three stages. In the first stage of this cooling are the relevant ones Hot strips each with a cooling rate Ag1 on an intermediate temperature ZT1 has been cooled. That concluded Cool down in air for a period of time t2 which in turn followed the third cooling stage in which the Tapes with a cooling rate Ag2 on one Temperature ZT2 have been cooled. On the between the End of the cooling device to the reel then covered the hot tapes are on the Temperature HT cooled, with which they have been reeled.
Die während der Herstellung der Warmbänder W1 - W4 aus den Schmelzen S1 und S2 eingehaltenen Endwalztemperaturen ET, die Warmbanddicken d, die jeweiligen Abkühlgeschwindigkeiten Ag1, die Zwischentemperatur ZT1, die Zeitdauer t2 der zwischengeschalteten Abkühlung an Luft, die jeweiligen Abkühlgeschwindigkeiten Ag2, die Zwischentemperatur ZT2 und die Haspeltemperaturen HT sind in Tabelle 2 angegeben.During the production of the hot tapes W1 - W4 from the Melting S1 and S2 compliant final rolling temperatures ET, the hot strip thicknesses d, the respective Cooling rates Ag1, the intermediate temperature ZT1, the duration t2 of the intermediate cooling Air, the respective cooling rates Ag2, the Intermediate temperature ZT2 and the reel temperatures HT are in Table 2.
In Tabelle 3 sind die für die betreffenden Warmbänder W1 - W4 ermittelten mechanischen Eigenschaften Zugfestigkeit Rm, Gleichmaßdehnung Ag, Dehnung A80 und Dehnung A5 sowie das jeweilige Produkt aus Rm*A5 und Rm*A80 angegeben.In Table 3 are those for the relevant hot strips W1 - W4 determined mechanical properties Tensile strength Rm, uniform elongation Ag, elongation A80 and Elongation A5 and the respective product of Rm * A5 and Rm * A80 specified.
Die aus der Schmelze S3 erzeugten Warmbänder W5 - W10 sind dagegen nach dem Verlassen der Warmwalzstaffel einer Abkühlung unterzogen worden, bei der sie mit einer Abkühlgeschwindigkeit Ag1 auf eine Zwischentemperatur ZT1 und anschließend mit einer Abkühlgeschwindigkeit Ag2 auf die jeweilige Haspeltemperatur HT abgekühlt worden sind. In Tabelle 4 sind die betreffenden Verfahrensparameter sowie die Dicke d der Warmbänder W5 bis W10 angegeben. Tabelle 5 enthält die zugehörigen Angaben zur jeweiligen Zugfestigkeit Rm, Gleichmaßdehnung Ag, Dehnung A80 und Dehnung A5 sowie zum jeweiligen Produkt aus Rm*A5 und Rm*A80. The hot strips W5-W10 produced from the melt S3, on the other hand, have been subjected to cooling after leaving the hot rolling scale, where they have been cooled at a cooling rate Ag1 to an intermediate temperature ZT1 and then at a cooling rate Ag2 to the respective reeling temperature HT. Table 4 shows the relevant process parameters and the thickness d of the hot strips W5 to W10. Table 5 contains the corresponding information on the respective tensile strength Rm, uniform elongation Ag, elongation A80 and elongation A5 as well as the respective product of Rm * A5 and Rm * A80.
Claims (24)
1,5 - 3,5 % beträgt,
mindestens eines der Elemente Ti oder Nb in Gehalten von jeweils 0,005 - 0,15 %,
sowie wahlweise eines oder mehrere der folgenden Elemente
zu Dünnbrammen,
1.5-3.5%,
at least one of the elements Ti or Nb in amounts of 0.005 - 0.15% each,
and optionally one or more of the following elements
to thin slabs,
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT02019314T ATE343649T1 (en) | 2002-08-28 | 2002-08-28 | METHOD FOR PRODUCING A PEARLITE-FREE HOT ROLLED STEEL STRIP AND HOT STRIP PRODUCED BY THIS METHOD |
DE50208550T DE50208550D1 (en) | 2002-08-28 | 2002-08-28 | A method for producing a pearlite-free hot rolled steel strip and hot strip produced by this method |
EP02019314A EP1396549B1 (en) | 2002-08-28 | 2002-08-28 | Process for manufacturing hot rolled pearlite-free steel strip and hot strip obtained thereby |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP02019314A EP1396549B1 (en) | 2002-08-28 | 2002-08-28 | Process for manufacturing hot rolled pearlite-free steel strip and hot strip obtained thereby |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1396549A1 true EP1396549A1 (en) | 2004-03-10 |
EP1396549B1 EP1396549B1 (en) | 2006-10-25 |
Family
ID=31502704
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP02019314A Expired - Lifetime EP1396549B1 (en) | 2002-08-28 | 2002-08-28 | Process for manufacturing hot rolled pearlite-free steel strip and hot strip obtained thereby |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1396549B1 (en) |
AT (1) | ATE343649T1 (en) |
DE (1) | DE50208550D1 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2398928A1 (en) * | 2009-02-20 | 2011-12-28 | Nucor Corporation | A hot rolled thin cast strip product and method for making the same |
CN101717890B (en) * | 2009-11-26 | 2012-09-05 | 三一重工股份有限公司 | Cast low alloy steel for grader blade and preparation method |
CN109536686A (en) * | 2018-12-12 | 2019-03-29 | 贵阳市白云区科创生产力促进中心 | The preparation method of manganese TRIP steel in a kind of Nb-microalloying |
WO2020130614A2 (en) | 2018-12-19 | 2020-06-25 | 주식회사 포스코 | High strength hot-rolled steel sheet having excellent hole expansion ratio and manufacturing method for same |
CN112522595A (en) * | 2019-09-19 | 2021-03-19 | 宝山钢铁股份有限公司 | High-strength thin-specification fire-resistant weather-resistant steel plate/steel belt and production method thereof |
WO2021125563A1 (en) | 2019-12-20 | 2021-06-24 | 주식회사 포스코 | High-strength hot-rolled steel sheet having excellent yield ratio, and method for manufacturing same |
WO2022108220A1 (en) | 2020-11-17 | 2022-05-27 | 주식회사 포스코 | High-strength hot-rolled steel sheet, hot-rolled plated steel sheet, and manufacturing methods therefor |
KR20220087989A (en) | 2020-12-18 | 2022-06-27 | 주식회사 포스코 | High strength hot-rolled steel sheet and hot-rolled plated steel sheet, and manufacturing method for thereof |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0295500A1 (en) * | 1987-06-03 | 1988-12-21 | Nippon Steel Corporation | Hot rolled steel sheet with a high strength and a distinguished formability |
EP0789090A1 (en) * | 1995-08-31 | 1997-08-13 | Kawasaki Steel Corporation | Hot-rolled steel sheet and process for producing the same |
EP0881306A1 (en) * | 1997-05-12 | 1998-12-02 | RECHERCHE ET DEVELOPPEMENT DU GROUPE COCKERILL SAMBRE, en abrégé: RD-CS | Ductile steel with high yield strength and process for manufacturing same |
JP2000034537A (en) * | 1998-07-16 | 2000-02-02 | Nippon Steel Corp | High strength hot rolled steel plate excellent in machinability, and its production |
US6190469B1 (en) * | 1996-11-05 | 2001-02-20 | Pohang Iron & Steel Co., Ltd. | Method for manufacturing high strength and high formability hot-rolled transformation induced plasticity steel containing copper |
US6328826B1 (en) * | 1999-07-30 | 2001-12-11 | Usinor | Method of fabricating “TRIP” steel in the form of thin strip, and thin strip obtained in this way |
-
2002
- 2002-08-28 DE DE50208550T patent/DE50208550D1/en not_active Expired - Lifetime
- 2002-08-28 AT AT02019314T patent/ATE343649T1/en not_active IP Right Cessation
- 2002-08-28 EP EP02019314A patent/EP1396549B1/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0295500A1 (en) * | 1987-06-03 | 1988-12-21 | Nippon Steel Corporation | Hot rolled steel sheet with a high strength and a distinguished formability |
EP0789090A1 (en) * | 1995-08-31 | 1997-08-13 | Kawasaki Steel Corporation | Hot-rolled steel sheet and process for producing the same |
US6190469B1 (en) * | 1996-11-05 | 2001-02-20 | Pohang Iron & Steel Co., Ltd. | Method for manufacturing high strength and high formability hot-rolled transformation induced plasticity steel containing copper |
EP0881306A1 (en) * | 1997-05-12 | 1998-12-02 | RECHERCHE ET DEVELOPPEMENT DU GROUPE COCKERILL SAMBRE, en abrégé: RD-CS | Ductile steel with high yield strength and process for manufacturing same |
JP2000034537A (en) * | 1998-07-16 | 2000-02-02 | Nippon Steel Corp | High strength hot rolled steel plate excellent in machinability, and its production |
US6328826B1 (en) * | 1999-07-30 | 2001-12-11 | Usinor | Method of fabricating “TRIP” steel in the form of thin strip, and thin strip obtained in this way |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 05 14 September 2000 (2000-09-14) * |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2398928A1 (en) * | 2009-02-20 | 2011-12-28 | Nucor Corporation | A hot rolled thin cast strip product and method for making the same |
EP2398928A4 (en) * | 2009-02-20 | 2014-12-24 | Nucor Corp | A hot rolled thin cast strip product and method for making the same |
US9296040B2 (en) | 2009-02-20 | 2016-03-29 | Nucor Corporation | Hot rolled thin cast strip product and method for making the same |
EP3757244A1 (en) * | 2009-02-20 | 2020-12-30 | Nucor Corporation | A hot rolled thin cast strip product and method for making the same |
CN101717890B (en) * | 2009-11-26 | 2012-09-05 | 三一重工股份有限公司 | Cast low alloy steel for grader blade and preparation method |
CN109536686A (en) * | 2018-12-12 | 2019-03-29 | 贵阳市白云区科创生产力促进中心 | The preparation method of manganese TRIP steel in a kind of Nb-microalloying |
KR20200076239A (en) | 2018-12-19 | 2020-06-29 | 주식회사 포스코 | High strength hot-rolled steel sheet having excellent hole expansion ratio and manufacturing method for the same |
WO2020130614A2 (en) | 2018-12-19 | 2020-06-25 | 주식회사 포스코 | High strength hot-rolled steel sheet having excellent hole expansion ratio and manufacturing method for same |
CN112522595A (en) * | 2019-09-19 | 2021-03-19 | 宝山钢铁股份有限公司 | High-strength thin-specification fire-resistant weather-resistant steel plate/steel belt and production method thereof |
CN112522595B (en) * | 2019-09-19 | 2022-10-21 | 宝山钢铁股份有限公司 | High-strength thin-specification fire-resistant weather-resistant steel plate/steel belt and production method thereof |
WO2021125563A1 (en) | 2019-12-20 | 2021-06-24 | 주식회사 포스코 | High-strength hot-rolled steel sheet having excellent yield ratio, and method for manufacturing same |
KR20210079831A (en) | 2019-12-20 | 2021-06-30 | 주식회사 포스코 | High strength hot-rolled steel sheet having excellent yield ratio and manufactueing method for the same |
WO2022108220A1 (en) | 2020-11-17 | 2022-05-27 | 주식회사 포스코 | High-strength hot-rolled steel sheet, hot-rolled plated steel sheet, and manufacturing methods therefor |
KR20220087989A (en) | 2020-12-18 | 2022-06-27 | 주식회사 포스코 | High strength hot-rolled steel sheet and hot-rolled plated steel sheet, and manufacturing method for thereof |
Also Published As
Publication number | Publication date |
---|---|
ATE343649T1 (en) | 2006-11-15 |
DE50208550D1 (en) | 2006-12-07 |
EP1396549B1 (en) | 2006-10-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2924140B1 (en) | Method for manufacturing a high strength flat steel product | |
EP2690183B1 (en) | Hot-rolled steel flat product and method for its production | |
EP1918406B1 (en) | Process for manufacturing steel flat products from boron microalloyed multi phase steel | |
DE19911287C1 (en) | Process for producing a hot strip | |
EP1918402B1 (en) | Process for manufacturing steel flat products from a steel forming a complex phase structure | |
EP1918403B1 (en) | Process for manufacturing steel flat products from a steel forming martensitic structure | |
EP2855717A1 (en) | Steel, sheet steel product and process for producing a sheet steel product | |
DE10259230A1 (en) | Method of making a steel product | |
WO2015117934A1 (en) | High-strength flat steel product having a bainitic-martensitic microstructure and method for producing such a flat steel product | |
DE60315129T2 (en) | METHOD FOR PRODUCING AN UNWORKED STEEL HARDWARE PRODUCT HAVING A HIGH COPPER CONTENT AND THEREFORE OBTAINED IRON SHED PRODUCT | |
WO2014016421A1 (en) | Cold-rolled flat steel product and method for the production thereof | |
DE2454163A1 (en) | METHOD OF CONTROLLING THE TEMPERATURE OF STEEL DURING HOT ROLLING ON A CONTINUOUS HOT ROLLING DEVICE | |
WO2015024903A1 (en) | Method for producing a steel component | |
DE2924167A1 (en) | METHOD OF MANUFACTURING COLD-ROLLED STEEL SHEET WITH DOUBLE-PHASE STRUCTURE | |
WO2008052921A1 (en) | Method for manufacturing flat steel products from a multiphase steel alloyed with silicon | |
EP1398390B1 (en) | Steel with a very fine ferritic and martensitic microstructure having a high tensile strength | |
EP1396549B1 (en) | Process for manufacturing hot rolled pearlite-free steel strip and hot strip obtained thereby | |
DE10130774C1 (en) | Production of a high strength cold-formed product comprises pre-casting a steel to a pre-material, hot rolling into a hot strip so that the micro-alloying elements remain dissolved, coiling, cold-forming to a product, and annealing | |
EP1453984B1 (en) | Method for the production of hot strip or sheet from a micro-alloyed steel | |
EP1918404B1 (en) | Process for manufacturing steel flat products from aluminium alloyed multi phase steel | |
EP1396550A1 (en) | Method for manufacturing hot strip | |
EP3872194A1 (en) | Method for producing hot-rolled flat steel product and flat steel product | |
DE3437637A1 (en) | Process for producing heavy plate | |
WO2021213647A1 (en) | Hot-rolled flat steel product and method for the production thereof | |
WO2023025635A1 (en) | Cold-rolled flat steel product and method for the production thereof |
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: 20030708 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL LT LV MK RO SI |
|
AKX | Designation fees paid |
Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: THYSSENKRUPP STEEL AG |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SK TR |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SK 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: 20061025 Ref country code: CZ 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: 20061025 Ref country code: FI 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: 20061025 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: 20061025 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D Free format text: NOT ENGLISH |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D Free format text: LANGUAGE OF EP DOCUMENT: GERMAN |
|
REF | Corresponds to: |
Ref document number: 50208550 Country of ref document: DE Date of ref document: 20061207 Kind code of ref document: P |
|
GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) |
Effective date: 20061122 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
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: 20070125 Ref country code: BG 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: 20070125 Ref country code: SE 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: 20070125 |
|
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 FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20070205 |
|
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: 20070326 |
|
ET | Fr: translation filed | ||
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FD4D |
|
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: 20070726 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
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: 20070126 Ref country code: MC Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20070831 Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20070831 Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20070831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20070828 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: EE 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: 20061025 |
|
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: 20070828 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: 20061025 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: TR 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: 20061025 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 20140820 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20140820 Year of fee payment: 13 Ref country code: FR Payment date: 20140820 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: IT Payment date: 20140826 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: BE Payment date: 20140901 Year of fee payment: 13 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20150828 |
|
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: 20150828 |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MM Effective date: 20150901 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20160429 |
|
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: 20150901 |
|
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: 20150828 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: BE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150831 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20200820 Year of fee payment: 19 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 50208550 Country of ref document: DE |
|
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: 20220301 |