EP0780480A1 - Process for manufacturing high strength cold rolled steel strip excellent in formability with isotropic mechanical properties - Google Patents

Process for manufacturing high strength cold rolled steel strip excellent in formability with isotropic mechanical properties Download PDF

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EP0780480A1
EP0780480A1 EP96114389A EP96114389A EP0780480A1 EP 0780480 A1 EP0780480 A1 EP 0780480A1 EP 96114389 A EP96114389 A EP 96114389A EP 96114389 A EP96114389 A EP 96114389A EP 0780480 A1 EP0780480 A1 EP 0780480A1
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Prior art keywords
steel
max
rolling
content
cold
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German (de)
French (fr)
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Bernhard Dr. Engl
Günter Dipl.-Ing. Stich
Klaus-Dieter Horn
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ThyssenKrupp Steel Europe AG
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Fried Krupp AG Hoesch Krupp
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0436Cold rolling
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0447Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
    • C21D8/0473Final recrystallisation annealing

Definitions

  • the invention relates to a method for producing a strip steel according to the preamble of claim 1, wherein such steels and their composition belong to the prior art.
  • Cold rolled steel strip is widely used for the production of cold formed products. Depending on the type of forming process, different properties (characteristic values) are required.
  • Good formability is characterized by the highest possible r values, which characterize the deep-drawability, high n values, which characterize the stretchability, and high elongation values, which characterize the plane strain properties.
  • the method according to the invention is suitable for setting yield strengths in the range between 200 and 420 N / mm 2 .
  • the mechanical properties are isotropic.
  • the process in its individual variants also allows higher r values to be set and offers the possibility of achieving bake hardening.
  • the advantages of continuous annealing or hot-dip coating can also be included.
  • the advantages according to the invention can be achieved with Ti, Nb, V or Zr.
  • the process according to the invention permits the production of isotropic strip steels not only by the hood but also by the continuous process and thus allows bakehardening to be achieved and refinement by the hot-dip process.
  • Table 1 shows the chemical composition of the steels.
  • the steels were alloyed with at least the amount of elements Ti and / or Nb or V required for stoichiometric nitrogen setting.
  • Steels 4 and 9 were also alloyed with phosphorus to increase strength.
  • Table 2 shows the manufacturing conditions for the steels. It shows the combination of properties according to the invention of low final roll temperature below A r3 and high reel temperature (> 650 ° C.).
  • Table 3 shows the mechanical quality values, the degree of skin passage and the grain size of the steels of 70% cold-rolled strip. Due to the hot strip production according to the invention, the skin pass rate on the cold strips could be approx. Can be set 1/3 lower. Furthermore, high r m values (1.4 - 1.65) were achieved with vacuum decarburized steels, with low ⁇ r values ( ⁇ 0.1).
  • Fig. 1 the tip height is plotted against the degree of cold rolling for the continuously annealed steels and in Fig. 2 that for the annealed steels.
  • the records show that between 50 and 85% low-strip cold strips were produced in the case of the continuously annealed as well as the annealed annealed steels.
  • the usual degree of cold rolling of approx. 70% the tip height of all examples is tip-free.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

Zur Erzeugung eines kaltgewalzten, höherfesten Bandstahles mit guter Umformbarkeit bei isotropen Eigenschaften aus Stahl mit folgender Zusammensetzung in Gewichtsprozenten: max.: 0,08 % C: max.: 0,10 % P; max.: 1,0 % Si: max.: 0,02 % S; max.: 1,8 % Mn: max.: 0,08 % Al max.: 0,008 % N und einem oder mehreren der Elemente Titan, Vanadium, Niob, Rest Eisen, durch Warmwalzen, Kaltwalzen, rekristallisierendes Glühen und nachfolgendes Dressieren, wird vorgeschlagen, daß entweder der Gehalt an Ti oder V mind. dem Dreifachen des Gehalts an N oder der Gehalt an Nb oder Zr mind. dem Sechsfachen des Gehalts an N entspricht, und daß der Stahl zu Brammen abgegossen, vor dem Warmwalzen auf eine Temperatur von mind. 1000°C erwärmt, zu Warmband ausgewalzt wird, wobei die Endwalztemperatur unter Ar3 und die Haspeltemperatur oberhalb 650°C liegt, und der Stahl nach der Warmwalzung mit einem Abwalzgrad zwischen 55 und 85 % kalt ausgewalzt, dann rekristallisierend geglüht und abschließend dressiert wird, und die Streckgrenze des Stahls nach zusätzlicher simulierter Lackeinbrennbehandlung mit mind. 20 min - 170°C mindestens 200 N/mm<2> beträgt.To produce a cold-rolled, high-strength steel strip with good formability and isotropic properties from steel with the following composition in percent by weight: max .: 0.08% C: max .: 0.10% P; max .: 1.0% Si: max .: 0.02% S; max .: 1.8% Mn: max .: 0.08% Al max .: 0.008% N and one or more of the elements titanium, vanadium, niobium, remainder iron, by hot rolling, cold rolling, recrystallizing annealing and subsequent dressing proposed that either the Ti or V content be at least three times the N content or the Nb or Zr content be at least six times the N content, and that the steel be cast into slabs prior to hot rolling to a temperature of heated at least 1000 ° C, rolled into hot strip, the final rolling temperature being below Ar3 and the coiling temperature above 650 ° C, and the steel is cold-rolled after hot rolling with a degree of rolling between 55 and 85%, then annealed to recrystallize and finally treated , and the yield strength of the steel after additional simulated paint baking treatment with at least 20 min - 170 ° C is at least 200 N / mm <2>.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung eines Bandstahles gemäß dem Oberbegriff des Anspruchs 1, wobei derartige Stähle und deren Zusammensetzung zum Stand der Technik gehören.The invention relates to a method for producing a strip steel according to the preamble of claim 1, wherein such steels and their composition belong to the prior art.

Kaltgewalztes Stahlband wird vielfach zur Herstellung von kaltumgeformten Erzeugnissen verwendet. Je nach Art des Umformverfahrens sind unterschiedliche Eigenschaften (Kennwerte) erforderlich.Cold rolled steel strip is widely used for the production of cold formed products. Depending on the type of forming process, different properties (characteristic values) are required.

Die steigenden Anforderungen bezüglich der Anwendungs- und Gebrauchseigenschaften erfordern zunehmend noch bessere mechanische, insbesondere Umformeigenschaften. Eine gute Umformbarkeit ist gekennzeichnet durch möglichst hohe, die Tiefziehbarkeit kennzeichnende r-Werte, hohe, die Streckziehbarkeit kennzeichnende n-Werte und hohe, die plane strain-Eigenschaften kennzeichnende Dehnungswerte.The increasing requirements with regard to the application and use properties increasingly require even better mechanical, in particular forming, properties. Good formability is characterized by the highest possible r values, which characterize the deep-drawability, high n values, which characterize the stretchability, and high elongation values, which characterize the plane strain properties.

Es hat sich als vorteilhaft erwiesen, wenn die Umformeigenschaften in den verschiedenen Richtungen, insbesondere in der Längs-, der Quer- und der Diagonalrichtung möglichst gleich sind, d. h. weitgehend isotrop sind. Wenn diese Bedingung für den r-Wert zutrifft, bedeutet dies außerdem, daß der sog. Δr-Wert sehr klein ist und nach dem Abpressen von rotationssymmetrischen Teilen weitgehende Freiheit von Zipfeln erreicht wird. Die Vorteile isotroper Eigenschaften drücken sich im wesentlichen in einer Gleichmäßigkeit des Stoffflusses und einer Reduzierung des Blechverschnitts aus.It has proven to be advantageous if the forming properties in the different directions, in particular in the longitudinal, transverse and diagonal directions, are as equal as possible, i. H. are largely isotropic. If this condition applies to the r-value, this also means that the so-called .DELTA.r-value is very small and that, after pressing off rotationally symmetrical parts, extensive freedom from corners is achieved. The advantages of isotropic properties are essentially expressed in the uniformity of the material flow and a reduction in the sheet waste.

Die ebenfalls zunehmenden Anstrengungen im Leichtbau erfordern zur Erreichnung von Gewichtsreduzierungen den Einsatz von dünneren Blechen. Zum Ausgleich des durch die Blechdickenreduzierung verursachten Festigkeitsverlustes muß die Festigkeit des Blechs gesteigert werdenThe increasing efforts in lightweight construction also require the use of thinner sheets to achieve weight reductions. To compensate for the loss of strength caused by the reduction in sheet thickness, the strength of the sheet must be increased

Wegen des naturbedingten Abfalls der Umformbarkeit infolge einer Festigkeitserhöhung ist ein vorherrschendes Ziel der Werkstoffentwicklung, bei der Verwirklichung höherer Festigkeiten den Verlust an Umformbarkeit möglichst gering zu halten.Because of the natural drop in formability as a result of an increase in strength, a predominant goal of material development is to keep the loss of formability as low as possible when realizing higher strengths.

Nach dem Stand der Entwicklung sind zahlreiche höherteste Stähle mit Eignung zur Kaltumformbarkeit bekannt. Der erreichte Stand ist im wesentlichen in den Stahl-Eisen-Werkstoffblättern 093 und 094 für mikrolegierte sowie P-legierte mit und ohne Bake-hardening (BH) wiedergegeben. BH-Eigenschaften lassen sich besonders gut nach einem der neuartigen Durchlaufglühverfahren, z. T. gekoppelt mit einer Schmelztauchveredlung erzielen. Die Bandsauberkeit sowie die Gleichmäßigkeit der Eigenschaften lassen sich in diesen kontinuierlichen Bandverfahren sehr gut einstellen.According to the state of development, numerous higher-grade steels with suitability for cold formability are known. The status achieved is essentially reproduced in steel-iron material sheets 093 and 094 for micro-alloyed and P-alloyed with and without bake-hardening (BH). BH properties can be particularly well after one of the new continuous annealing processes, for. Achieve T. coupled with a hot dip. The belt cleanliness and the uniformity of the properties can be adjusted very well in this continuous belt process.

Auch gibt es seit längerer Zeit erfolgreiche Bemühungen zur Erzielung isotroper Eigenschaften. Ein isotroper Werkstoff zeigt beim Abpressen rotationssymmetrischer Teile keine Zipfelbildung. Beispiel hierfür ist die Anzeige "B-Faktor" von Fa. Brockhaus, "Der Spiegel", Nr. 19/1966, Seite 125. Dieses Beispiel beinhaltet jedoch nicht ausdrücklich die Herstellung höherfester Stähle und erfordert entweder sehr hohe Kaltwalzgrade oder sogar eine normalisierende Glühung zur Einstellung der Zipfelfreiheit.There have also been successful efforts to achieve isotropic properties for a long time. An isotropic material shows no tip formation when pressing rotationally symmetrical parts. An example of this is the "B factor" display from Brockhaus, "Der Spiegel", No. 19/1966, page 125. However, this example does not explicitly include the production of high-strength steels and either requires very high degrees of cold rolling or even normalizing annealing for setting the tip clearance.

In jüngster Zeit ist das Beispiel eines höherfesten Feinblechstahls mit Ti-Legierung zur Erzielung von Zipfelfreiheit aus der DE-PS 38 03 064 bekannt worden. Diese Entwicklung ist jedoch auf das Haubenglühverfahren beschränkt und muß deshalb auf die genannten Vorteile bei Anwendung des kontinuierlichen Glühens sowie der Oberflächenveredlung nach einem Schmelztauchverfahren verzichten. Des weiteren bleibt die Möglichkeit einer Steigerung der Festigkeitseigenschaften, z. B. der Streckgrenze, auf rd. 220 bis 280 N/mm2 beschränkt. Ein weiterer Nachteil sind die ausschließlich niedrigen r-Werte um 1,0, wodurch die Herstellung von Tiefziehteilen beeinträchtigt ist. Zudem wird bei diesem Konzept die höhere Festigkeit wesentlich durch den Verfestigungsmechanismus einer Kornverfeinerung erzielt. Feinkorn bedingt vergleichsweise hohen Aufwand beim Dressieren. Bei lediglich normaler Dressierung bestünde die Gefahr von Fließfigurenbildung und damit Von Versagen bei Außenhautteilen. Die im vorliegenden Fall notwendigerweise hohen Dressiergrade verringern jedoch die Umformeigenschaften gegenüber normaler Dressierung.Recently, the example of a high-strength sheet steel with a Ti alloy for achieving tip freedom has become known from DE-PS 38 03 064. However, this development is limited to the hood annealing process and must therefore forego the advantages mentioned when using continuous annealing and surface finishing using a hot-dip process. Furthermore, there remains the possibility of increasing the strength properties, e.g. B. the yield strength, to approx. 220 to 280 N / mm 2 limited. Another disadvantage is the exclusively low r-values around 1.0, which affects the production of deep-drawn parts. In addition, with this concept the higher strength is essentially achieved through the hardening mechanism of a grain refinement. Fine grain requires a comparatively high level of dressing. With only normal skin training, there would be a risk of formation of flow figures and thus failure of outer skin parts. However, in the present case, the high degrees of skin passaging necessarily reduce the forming properties compared to normal skin passaging.

Die Beschränkung auf die nahezu ausschließliche Wirkung der Kornverfeinerung über Titan machen außerdem eine genaue Abstimmung von Warm-, Kaltwalz- und Glühbedingungen auf die jeweils gegebene chem. Zusammensetzung erforderlich, wodurch hohe Anforderung an die Treffsicherheit bei den genannten Fertigungsbedingungen gegeben sind. Ein weiterer Nachteil ist in der Beschränkung der Walzendtemperatur auf Werte oberhalb von Ar3 zu sehen, wodurch vor allem das Walzen von Bändern mit geringer Enddicke aufgrund des damit verbundenen höheren Temperaturverlustes erschwert wird.The restriction to the almost exclusive effect of grain refinement over titanium also makes an exact match of hot, cold rolling and annealing conditions to the given chem. Composition required, which places high demands on accuracy in the manufacturing conditions mentioned. Another disadvantage is the limitation of the final rolling temperature to values above A r3 , which in particular makes it difficult to roll strips with a small final thickness due to the associated higher temperature loss.

Hier setzt die vorliegende Erfindung mit den im Anspruch 1 angegebenen Merkmalen an. Das erfindungsgemäße Verfahren ist für die Einstellung von Streckgrenzen im Bereich zwischen 200 und 420 N/mm2 geeignet. Dabei sind die mechanischen Eigenschaften isotrop. Zudem läßt das Verfahren in seinen einzelnen Varianten die Einstellung auch höherer r-Werte zu und bietet die Möglichkeit zur Erzielung von Bake-hardening. Des weiteren können die Vorteile des kontinuierlichen Glühens oder der Schmelztauchveredlung mit einbezogen werden. Die erfindungsgemäßen Vorteile können mit Ti, Nb, V oder Zr erreicht werden.This is where the present invention comes in with the features specified in claim 1. The method according to the invention is suitable for setting yield strengths in the range between 200 and 420 N / mm 2 . The mechanical properties are isotropic. In addition, the process in its individual variants also allows higher r values to be set and offers the possibility of achieving bake hardening. The advantages of continuous annealing or hot-dip coating can also be included. The advantages according to the invention can be achieved with Ti, Nb, V or Zr.

Nach dem bisher aus der DE-PS 38 03 064 vorliegenden Erkenntnisstand wird die Herstellung unter Einhaltung einer Walzendtemperatur oberhalb von Ar3 vorgeschrieben. Demnach war bislang nicht bekannt, unter welchen Bedingungen die Vorteile einer abgesenkten Walzendtemperatur genutzt werden konnte.According to the knowledge available up to now from DE-PS 38 03 064, production is stipulated while maintaining a final roll temperature above A r3 . Accordingly, it was not previously known under which conditions the advantages of a reduced final roll temperature could be used.

Nach der vorliegenden Erfindung wird eine niedrige Walzendtemperatur mit einer hohen Haspeltemperatur kombiniert. Überraschend ergaben sich hierdurch Eigenschaften und Merkmale, wie sie bislang für Stahl mit isotropem Verhalten unbekannt waren:

  • Verringerter Zunderanfall beim Warmwalzen
  • Verminderter Dressieraufwand am Feinblech
According to the present invention, a low roll end temperature is combined with a high reel temperature. Surprisingly, this resulted in properties and characteristics that were previously unknown for steel with isotropic behavior:
  • Reduced scaling during hot rolling
  • Reduced skin pass work on the thin sheet

Das erfindungsgemäße Verfahren läßt die Herstellung isotroper Bandstähle nicht nur nach dem Hauben- sondern auch nach dem Durchlaufverfahren zu und erlaubt somit die Erzielung von Bakehardening sowie die Veredlung im Schmelztauchverfahren.The process according to the invention permits the production of isotropic strip steels not only by the hood but also by the continuous process and thus allows bakehardening to be achieved and refinement by the hot-dip process.

Bei Anwendung einer Vakuumentkohlung im Stahlwerk und Durchlaufglühen des Kaltbands kann neben Bakehardening überraschenderweise auch ein hoher r-Wert erzielt werden.When using vacuum decarburization in the steel mill and continuous annealing of the cold strip, a high r-value can surprisingly be achieved in addition to bakehardening.

Einige Beispiele sollen das Ergebnis des erfindungsgemäßen Verfahrens verdeutlichen.A few examples are intended to illustrate the result of the method according to the invention.

In der Tabelle 1 ist die chemische Zusammensetzung der Stähle aufgeführt.
Die Stähle wurden mindestens mit der zur stöchiometrischen Stickstoffabbindung erforderlichen Menge der Elemente Ti und/oder Nb oder V legiert. Zudem wurden die Stähle 4 und 9 zur Festigkeitserhöhung mit Phosphor legiert.
Table 1 shows the chemical composition of the steels.
The steels were alloyed with at least the amount of elements Ti and / or Nb or V required for stoichiometric nitrogen setting. Steels 4 and 9 were also alloyed with phosphorus to increase strength.

Tabelle 2 zeigt die Fertigungsbedingungen der Stähle.
Sie weist die erfindungsgemäße Eigenschaftskombination niedriger Walzendtemperatur unter Ar3 und hohe Haspeltemperatur (> 650 °C) aus.
Table 2 shows the manufacturing conditions for the steels.
It shows the combination of properties according to the invention of low final roll temperature below A r3 and high reel temperature (> 650 ° C.).

In der Tabelle 3 sind die mechanischen Gütewerte, der Dressiergrad und die Korngröße der Stähle von 70 % kaltgewalztem Band aufgeführt.
Aufgrund der erfindungsgemäßen Warmbandfertigung konnte der Dressiergrad an den Kaltbändern um rd. 1/3 niedriger eingestellt werden. Des weiteren wurden bei den vakuumentkohlten Stählen 1 - 4 hohe rm Werte (1,4 - 1,65), bei niedrigen Δr Werten (<±0,1) erreicht.
Table 3 shows the mechanical quality values, the degree of skin passage and the grain size of the steels of 70% cold-rolled strip.
Due to the hot strip production according to the invention, the skin pass rate on the cold strips could be approx. Can be set 1/3 lower. Furthermore, high r m values (1.4 - 1.65) were achieved with vacuum decarburized steels, with low Δ r values (<± 0.1).

In der Fig. 1 ist die Zipfelhöhe über dem Kaltwalzgrad für die durchlaufgeglühten Stähle und in Fig. 2 die für die haubengeglühten Stähle grafisch aufgetragen.
Die Aufzeichnungen zeigen, daß sowohl bei den durchlaufgeglühten als auch bei den haubengeglühten Stählen bei Kaltwalzgraden zwischen 50 und 85 % zipfelarme Kaltbänder erzeugt wurden. Dabei war bei dem für die Kaltbandfertigung üblichen Kaltwalzgrad von rd. 70 % die Zipfelhöhe aller Beispiele zipfelfrei.
In Fig. 1 the tip height is plotted against the degree of cold rolling for the continuously annealed steels and in Fig. 2 that for the annealed steels.
The records show that between 50 and 85% low-strip cold strips were produced in the case of the continuously annealed as well as the annealed annealed steels. The usual degree of cold rolling of approx. 70% the tip height of all examples is tip-free.

Zudem ist der Fig. 2 zu entnehmen, daß eine abweichend von der Erfindung niedrige Haspeltemperatur (Stahl 7.2.1, 600 °C) eine hohe Zipfligkeit bewirkt. Dieses unterstreicht das Erfordernis der erfindungsgemäßen Kombination von hoher Haspeltemperatur bei niedriger Walzendtemperatur.

Figure imgb0001
Figure imgb0002
Figure imgb0003
It can also be seen from FIG. 2 that a reel temperature (steel 7.2.1, 600 ° C.) which is low in deviation from the invention results in a high degree of unevenness. This underlines the requirement of the combination according to the invention of a high reel temperature at a low final roll temperature.
Figure imgb0001
Figure imgb0002
Figure imgb0003

Claims (6)

Verfahren zur Herstellung eines kaltgewalzten, höhertesten Bandstahles mit guter Umformbarkeit bei isotropen Eigenschaften aus Stahl mit folgender Zusammensetzung in Gewichtsprozenten: max.: 0,08 % C   0,010 - 0,10 % P max.: 1,0 % Si   max.: 0,02 % S max.: 1,8 % Mn   max.: 0,08 % Al
max.: 0,008 % N
und einem oder mehreren der Elemente Titan, Vanadium, Niob, Zirkon, Rest Eisen, durch Warmwalzen, Kaltwalzen, rekristallisierendes Glühen und nachfolgendes Dressieren, wobei entweder der Gehalt an Ti oder V mind. dem Dreifachen des Gehalts an N oder der Gehalt an Nb oder Zr mind. dem Sechsfachen des Gehalts an N entspricht, und wobei der Stahl zu Brammen abgegossen, vor dem Warmwalzen auf eine Temperatur von mind. 1000°C erwärmt, zu Warmband ausgewalzt wird, wobei die Endwalztemperatur unter Ar3 und die Haspeltemperatur oberhalb 650°C liegt, und der Stahl nach der Warmwalzung mit einem Abwalzgrad zwischen 55 und 85 % kalt ausgewalzt, dann rekristallisierend geglüht und abschließend dressiert wird, und die Streckgrenze des Stahls nach zusätzlicher simulierter Lackeinbrennbehandlung mindestens 200 N/mm2 beträgt, wobei diese Behandlung mindestens 20 Min. bei mindestens 170°C durchgeführt wird.
Process for producing a cold-rolled, highest-quality steel strip with good formability and isotropic properties from steel with the following composition in percent by weight: max .: 0.08% C 0, 010 to 0.10% P max .: 1.0% Si max .: 0.02% S max .: 1.8% Mn max .: 0.08% Al
max .: 0.008% N
and one or more of the elements titanium, vanadium, niobium, zirconium, remainder iron, by hot rolling, cold rolling, recrystallizing annealing and subsequent tempering, wherein either the content of Ti or V is at least three times the content of N or the content of Nb or Zr corresponds to at least six times the N content, and the steel is poured into slabs, heated to a temperature of at least 1000 ° C before hot rolling, rolled into hot strip, the final rolling temperature below A r3 and the reel temperature above 650 ° C, and the steel is rolled cold after the hot rolling with a rolling degree between 55 and 85%, then annealed in a recrystallizing manner and finally treated, and the yield strength of the steel after additional simulated paint baking treatment is at least 200 N / mm 2 , this treatment being at least 20 Min. At least 170 ° C is carried out.
Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Stahl nach dem Kaltwalzen in einem Haubenofen rekristallisierend geglüht wird.A method according to claim 1, characterized in that the steel is annealed recrystallizing in a hood furnace after the cold rolling. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Stahl nach dem Kaltwalzen in einem Durchlaufofen rekristallisierend geglüht wird.A method according to claim 1, characterized in that the steel is annealed after re-crystallizing in a continuous furnace after cold rolling. Verfahren nach den Ansprüchen 1 und 3, dadurch gekennzeichnet, daß der Stahl nach dem Kaltwalzen und Glühen anschließend schmelztauchveredelt wird.Process according to claims 1 and 3, characterized in that the steel is subsequently hot-dip coated after cold rolling and annealing. Verfahren nach einem oder mehreren der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der Phosphorgehalt 0,035 bis 0,10 % beträgt.Method according to one or more of claims 1 to 4, characterized in that the phosphorus content is 0.035 to 0.10%. Verfahren nach einem oder mehreren der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Endwalztemperatur beim Warmwalzen kleiner gleich 8500C ist.Method according to one or more of claims 1 to 5, characterized in that the final rolling temperature during hot rolling is less than or equal 850 0 C.
EP96114389A 1995-12-16 1996-09-09 Process for manufacturing high strength cold rolled steel strip excellent in formability with isotropic mechanical properties Withdrawn EP0780480A1 (en)

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DE19547181A DE19547181C1 (en) 1995-12-16 1995-12-16 Mfg. cold-rolled, high strength steel strip with good shapability
DE19547181 1995-12-16

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EP1225235A2 (en) * 2001-01-23 2002-07-24 Salzgitter AG Process for manufacturing a cold rolled steel strip or sheet and steel strip or sheet obtainable by the process
KR100738849B1 (en) * 2000-04-22 2007-07-12 쉐플러 카게 Rolling bearing component

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BE1011066A3 (en) * 1997-03-27 1999-04-06 Cockerill Rech & Dev Niobium steel and method for manufacturing flat products from it.
TW515847B (en) * 1997-04-09 2003-01-01 Kawasaki Steel Co Coating/baking curable type cold rolled steel sheet with excellent strain aging resistance and method for producing the same
DE19736509A1 (en) * 1997-08-22 1999-04-22 Krupp Ag Hoesch Krupp Titanium-alloyed, isotropic, earing-free, cold rolled strip steel is produced
MXPA01006761A (en) * 1998-12-30 2003-05-15 Mije Rob V D Steel band with good forming properties and method for producing same.
DE10333875A1 (en) * 2003-07-25 2005-02-17 Ina-Schaeffler Kg Needle bearing has cold-formed outer ring made from steel, ratio of wall thickness of ring to diameter of needles being 1:20 - 1:5
DE102005058658A1 (en) * 2005-12-07 2007-06-14 Kermi Gmbh Method for reducing the wall thickness of steel radiators
CN102312167B (en) * 2010-06-29 2014-04-02 鞍钢股份有限公司 High-strength hot rolled steel plate for double-sided enamel and manufacturing method thereof
CN102787215A (en) * 2011-05-19 2012-11-21 宝山钢铁股份有限公司 Method for RH nitrogen-increasing control of glassed steel
CN102328191B (en) * 2011-10-19 2013-08-28 无锡市锡州冷拉型钢有限公司 Production process for C-shaped channel steel
CN105463321A (en) * 2015-12-08 2016-04-06 武汉钢铁(集团)公司 Batch annealing process plane isotropy steel and manufacturing method thereof
CN105483537B (en) * 2015-12-09 2018-10-16 武汉钢铁有限公司 Planar isotropy excellent yield strength is the cold-rolling and punching steel and its manufacturing method of 180MPa ranks

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CZ283200B6 (en) 1998-01-14
DE19547181C1 (en) 1996-10-10
CZ309496A3 (en) 1997-09-17
PL317513A1 (en) 1997-06-23
ES2104529T1 (en) 1997-10-16

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