EP2031081B1 - Dual-phase steel, flat product made of such dual-phase steel and method for manufacturing a flat product - Google Patents

Dual-phase steel, flat product made of such dual-phase steel and method for manufacturing a flat product Download PDF

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Publication number
EP2031081B1
EP2031081B1 EP07114399A EP07114399A EP2031081B1 EP 2031081 B1 EP2031081 B1 EP 2031081B1 EP 07114399 A EP07114399 A EP 07114399A EP 07114399 A EP07114399 A EP 07114399A EP 2031081 B1 EP2031081 B1 EP 2031081B1
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EP
European Patent Office
Prior art keywords
dual
phase steel
content
weight
strip
Prior art date
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EP07114399A
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German (de)
French (fr)
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EP2031081A1 (en
Inventor
Ekaterina Bocharova
Brigitte Hammer
Thomas Heller
Dorothea Mattissen
Günter STICH
Silke Strauss
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ThyssenKrupp Steel Europe AG
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ThyssenKrupp Steel Europe AG
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Publication date
Priority to ES07114399T priority Critical patent/ES2367713T3/en
Application filed by ThyssenKrupp Steel Europe AG filed Critical ThyssenKrupp Steel Europe AG
Priority to PL07114399T priority patent/PL2031081T3/en
Priority to AT07114399T priority patent/ATE516380T1/en
Priority to EP07114399A priority patent/EP2031081B1/en
Priority to US12/673,279 priority patent/US20110220252A1/en
Priority to CN2008801034281A priority patent/CN101802237B/en
Priority to JP2010520537A priority patent/JP5520221B2/en
Priority to PCT/EP2008/060382 priority patent/WO2009021898A1/en
Publication of EP2031081A1 publication Critical patent/EP2031081A1/en
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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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
    • Y10T29/49988—Metal casting
    • Y10T29/49991—Combined with rolling

Definitions

  • the invention relates to a dual-phase steel, the structure of which consists essentially of martensite and ferrite or bainite, wherein shares of retained austenite may be present and the dual-phase steel has a tensile strength of more than 950 MPa.
  • the invention likewise relates to a flat product produced from such a dual-phase steel and to a process for producing a flat product.
  • the generic term "flat product" typically includes steel strips and sheets of the type according to the invention.
  • the known steel contains, in addition to iron and the unavoidable impurities (in% by weight) 0.05-0.3% C, up to 1.5% Si, 0.01-0.3% Mn, up to 0.02 % P, 0.02% S, up to 0.01% N and 0, 01 - 3.0% Al.
  • the known steel should have a retained austenite content of not more than 7% and have Mg precipitates with a particle diameter of 0.01-5.0 ⁇ m at a distribution determined in more detail in this document.
  • the from the EP 1 637 618 A1 known steel to further increase its strength in addition to other optionally added alloying elements also contain contents of Cr and Mo of 0.005 - 5 wt .-% and 0.0051 - 2 wt .-% Cu, the contents of Cu should additionally reduce the risk of breakage ,
  • the Martenistanteil of the steel in question is about 5% to 20% of the predominantly martensitic-ferritic microstructure.
  • a flat product produced in this way has strengths of at least 500 N / mm 2 and at the same time good formability, without requiring particularly high contents of certain alloying elements.
  • JP-A-2000282175 discloses a steel, the structure of which consists of 60-90 vol.% Bainite and the remainder of ferrite, martensite and retained austenite for bodywork.
  • the object of the invention was to develop a steel and a flat product produced therefrom which has a strength of at least 950 MPa and good deformability.
  • the steel should be one Having a surface finish that allows using a simple manufacturing process, a flat product produced from this steel in the uncoated or provided with a corrosion-protective coating state to deform a complex-shaped component, such as a part of an automobile body.
  • a method should also be given that allows in a simple manner to produce in the above-mentioned manner manufactured flat products.
  • a the above-mentioned object solving flat product according to claim 21 according to the invention characterized in that it consists of a composite according to the invention and procured steel.
  • a steel according to the invention is characterized by high strengths of at least 950, in particular 980 MPa, with regular strengths of 1000 MPa and more being achieved. At the same time, the steel according to the invention has a yield strength of at least 580 MPa, in particular at least 600 MPa, and has an elongation A 80 of at least 10%.
  • steel according to the invention is particularly suitable for the production of complex shaped, highly loaded in practical use components, such as those required in the field of bodywork for automobiles.
  • the advantageous combination of properties of a steel according to the invention is achieved inter alia by possessing a dual-phase structure despite its high strengths.
  • the alloy of a steel according to the invention is composed to have a martensite content of at least 20% to a maximum of 70%.
  • residual austenite contents of up to 8% may be advantageous, with generally lower residual austenite contents of not more than 7% or less being preferred.
  • the remainder of the microstructure of a dual-phase steel according to the invention consists respectively of ferrite and / or bainite (bainitic ferrite + carbides).
  • the high strengths, good elongation properties and optimized surface textures are due to the adjustment of the dual-phase structure according to the invention achieved. This has been made possible by a narrow selection of the individual contents of the alloying elements present in a steel according to the invention besides iron and unavoidable impurities.
  • the invention provides a C content of 0.050-0.105% by weight.
  • the inventively provided levels of C have been chosen in view of the best possible weldability of the steel.
  • the advantageous effect of carbon in a steel according to the invention can be used particularly reliably if the C content of a steel according to the invention is 0.060-0.090% by weight, in particular 0.070-0.080% by weight.
  • Si is used in a steel according to the invention to increase the strength by hardening the ferrite or bainite.
  • a minimum content of Si of 0.10 wt .-% is provided, the effect of Si is particularly safe when the Si content of a steel according to the invention at least 0.2 wt .-%, in particular at least 0.25 wt .-% is.
  • adherence to this upper limit minimizes the risk of grain boundary oxidation.
  • the upper limit of the Si content has at the same time been set at 0.6% by weight. In this case, an unfavorable influence of Si on the properties of the steel according to the invention can be avoided with even greater certainty that the Si content of the steel according to the invention is limited to 0.4% by weight, in particular 0.35% by weight.
  • the Mn content of a steel according to the invention is in the range of 2.10-2.80% by weight in order to use, on the one hand, the strength-increasing effect and, on the other hand, the positive influence of Mn on martensite formation.
  • Mn also has a positive effect with regard to the lowering of the critical cooling rate after annealing, since it hinders the formation of perlite.
  • the positive effects of the presence of Mn in a steel according to the invention can be used with particular certainty if the Mn content is at least 2.20% by weight, in particular at least 2.45% by weight.
  • Negative effects of Mn on a steel according to the invention such as a reduction in elongation, deterioration of weldability or poorer suitability for hot-dip galvanizing, can be excluded with increased certainty that the Mn content to 2.70 wt .-%, in particular 2, 60 wt .-% is limited.
  • Cr also strengthens in a dual-phase steel according to the invention in contents of 0.2-0.8% by weight.
  • the effect of Cr is comparable to the effect of Mn.
  • the advantageous effects of Cr occur in particular when the Cr content is at least 0.3% by weight, in particular at least 0.55% by weight.
  • the Cr content of a steel according to the invention is limited to 0.8% by weight in order to reduce the risk of occurrence of grain boundary oxidation and to avoid a negative influence on the ductility of the steel according to the invention. This is especially ensured when the upper limit of the Chromium content of a steel according to the invention to at most 0.7 wt .-%, in particular 0.65 wt .-%, is set.
  • the presence of titanium at levels of at least 0.02% by weight also contributes to increasing the strength of a steel according to the invention by forming fine precipitates of TiC or Ti (C, N) and contributing to grain refining.
  • Another positive effect of Ti is the setting of possibly present nitrogen, so that the formation of boron nitrides in the steel according to the invention is prevented. These would have a strong negative impact on the elongation properties and, consequently, on the formability of a flat product according to the invention.
  • the presence of Ti thus ensures, in the case of an addition of boron to increase the strength, that the boron can fully develop its effect.
  • Ti is added in an amount which is more than 5.1 times the respective N content (ie Ti content> 1.5 (3.4 ⁇ N content)).
  • too high Ti contents lead to unfavorably high recrystallization temperatures, which has a negative effect, in particular, when cold-rolled flat products are produced from steel according to the invention, which are finally annealed. Therefore, the upper limit of the Ti content has been limited to 0.10 wt%.
  • the positive influence of Ti on the properties of a steel according to the invention can be used particularly reliably if its Ti content is 0.060-0.090% by weight, in particular 0.070-0.085% by weight.
  • the strength of the steel according to the invention is also increased by the amounts of B, which are optionally provided according to the invention, of up to 0.002% by weight and, as in the case of the addition of Mn, Cr and Mo in the case of the production of cold strip of steel according to the invention, the critical cooling rate lowered after annealing. Therefore, according to a particularly preferred embodiment of the invention, the B content is at least 0.0005 wt .-%. At the same time, however, excessively high contents of B can reduce the deformability of the steel according to the invention and adversely affect the expression of the dual-phase structure desired according to the invention. Optimized effects of boron can be used in a steel according to the invention in that the B content is limited to 0.0007-0.0016% by weight, in particular 0.0008-0.0013% by weight.
  • the inventively optional contents of molybdenum of at least 0.05% by weight also contribute to increasing the strength of a steel according to the invention.
  • the presence of Mo does not adversely affect the coatability of the flat product with a metallic coating and its ductility.
  • Practical experiments have shown that the positive effects of Mo up to contents of 0.25% by weight, in particular 0.22% by weight, can be used particularly effectively, even from a cost point of view.
  • contents of Mo of at least 0.05% by weight have a positive effect on the properties of a steel according to the invention.
  • the desired effect of molybdenum occurs a steel according to the invention, in particular if its Mo content is 0.065-0.18% by weight, in particular 0.08-0.13% by weight.
  • Mo content is 0.065-0.18% by weight, in particular 0.08-0.13% by weight.
  • Cr contents of less than 0.3% by weight it is advantageous to add 0.05-0.22% by weight of Mo to secure the required strength of the steel according to the invention.
  • Aluminum is used in the melting of a steel according to the invention for deoxidizing and for setting nitrogen which may be present in the steel.
  • Al may be added to the steel according to the invention in contents of less than ⁇ 0.1% by weight, the desired effect of Al occurring particularly safely if its contents in the range of 0.01-0.06 wt .-%, in particular 0.020 - 0.050 wt .-%, are.
  • the steel according to the invention may, to further increase its strength, have copper in contents of up to 0.20% by weight.
  • a copper content has a particularly favorable effect when it is in the range of 0.08 to 0.12 wt .-%.
  • nickel may be added to the steel according to the invention in order to further improve the hardenability and, accordingly, the strength of a steel according to the invention.
  • Ca can be used for deoxidation like Al in steelmaking.
  • the presence of Ca in amounts of up to 0.005 wt .-%, in particular from 0.002 to 0.004 wt .-%, also favor the formation of a fine-grained structure.
  • Nitrogen is allowed in inventive steel only in amounts of up to 0.012 wt .-%, in order to avoid the formation of boron nitrides especially in the simultaneous presence of B.
  • the N content is preferably limited to 0.007% by weight.
  • the P content is according to the invention preferably limited to ⁇ 0.1, in particular ⁇ 0.02 wt .-%, with particularly good results at levels of less than 0.010 wt .-% can be achieved.
  • a dual phase steel composed according to the invention is first melted, then the melt to a precursor, such as slab or thin slab, cast, then reheated the precursor at a hot rolling start temperature of 1100 - 1300 ° C. or held, then the precursor hot rolled at a hot rolling end temperature of 800 - 950 ° C to a hot strip and finally the hot strip at a reel temperature of up to 650 ° C, in particular 500 - 650 ° C, reeled.
  • hot strip composed according to the invention reacts insensitive to the change in the coiler temperature and can always achieve strengths which are in the range of 1000 MPa and yield strengths of 750 to 890 MPa.
  • the reel temperature can be varied over a wide range in order to influence the respective desired properties and microstructural characteristics in a targeted manner.
  • particularly suitable reel temperatures are in the range of 500-650 ° C, with reel temperatures of 530-580 ° C as have proved particularly favorable, since at temperatures of more than 580 ° C with increasing reel temperature, the risk of grain boundary oxidation increases and lying below 500 ° C reel temperatures, the strength of the hot strip increases so much that a subsequent deformation can be difficult.
  • the hot strip obtained in the manner according to the invention should remain uncoated or be electrolytically coated with a metallic coating as a hot strip, no annealing of the flat product is required.
  • the hot-rolled strip is to be coated with a metallic coating by hot-dip galvanizing, then it is first annealed at a maximum annealing temperature of 600 ° C. and then cooled to the temperature of the coating bath, which may be, for example, a zinc bath. After passing through the zinc bath, the coated hot strip can be conventionally cooled to room temperature.
  • cold rolled strips can also be produced from composite steel.
  • a composite according to the invention dual-phase steel melted, then cast the melt into a precursor, such as slab or thin slab, then reheated or held the precursor at a hot rolling start temperature of 1100-1300 ° C, then the hot rolled at a final hot rolling temperature of 800-950 ° C to a hot strip, the pre-product obtained hot strip at a reel temperature of up to 650 ° C, in particular 500 - 650 ° C, reeled, then the hot strip cold rolled into a cold strip, then the cold strip annealed at a 700 - 900 ° C amount annealing temperature and finally cooled the cold strip controlled
  • the cold strip thus produced can also be provided with a protective coating against corrosion.
  • the cold strip to be cold rolled to cold strip is preferably at least 500 ° C, in particular at least 530 ° C or at least 550 ° C, reeled.
  • Such cold-rolled Cold rolled strip according to the invention typically has thicknesses of 0, 8-2.5 mm.
  • the flat product according to the invention is provided with a metallic protective coating, this can be done, for example, by hot-dip galvanizing, galvannealing or electrolytic coating. If necessary, a pre-oxidation can be carried out before the coating in order to ensure a secure connection of the metallic coating to the respective substrate to be coated.
  • the cold strip produced according to the invention remains uncoated or is to be electrolytically coated, an annealing treatment in a continuous annealing anneal takes place as a separate working step.
  • the maximum annealing temperatures achieved are in the range of 700-900 ° C at heating rates of 1-50 K / s.
  • the annealed cold strip for the targeted setting of the desired property combination according to the invention is preferably cooled in such a way that in the temperature range of 550-650 ° C cooling rates of at least 10 K / s are achieved in order to suppress the formation of perlite.
  • the strip can be held for a period of 10-100 s or cooled directly to room temperature at a cooling rate of 0.5-30 K / s.
  • the cold strip is to be coated by hot dip galvanizing, then the steps of annealing and coating can be combined.
  • the cold strip in continuous sequence through different furnace sections of a fire-coating plant, wherein in the individual furnace sections have different temperatures, the maximum in the range of 700 - 900 ° C, with heating rates in the range of 2 - 100 K / s should be selected.
  • the strip is then held at this temperature for 10-200 seconds.
  • the strip is then cooled to the temperature of the respective coating bath, which is typically below 500 ° C., which is typically a zinc bath, the cooling rate also being more than 10 K in the temperature range 550-650 ° C. in this case / s should be.
  • the cold strip can be kept at the respective temperature for 10 - 100 s. Then the annealed cold strip passes through the respective coating bath, which is preferably a zinc bath. This is followed by either cooling to room temperature to obtain a conventionally hot-dip galvanized cold-rolled strip or rapid heating followed by cooling to room temperature to produce a galvanized cold-rolled strip.
  • the respective coating bath which is preferably a zinc bath. This is followed by either cooling to room temperature to obtain a conventionally hot-dip galvanized cold-rolled strip or rapid heating followed by cooling to room temperature to produce a galvanized cold-rolled strip.
  • the cold-rolled strip in the coated or uncoated state after the annealing treatment may be subjected to a skin pass rolling in which the skin passages ranging up to 2% are adjusted.
  • the hot rolled strips thus obtained were rewound at a coiler temperature of 550 ° C., adjusted to an accuracy of +/- 30 ° C., before being cold rolled to a thickness of 50%, 65% and 70%, respectively from 0.8 mm to 2 mm cold rolled.
  • Table 2 shows the microstructural state, the mechanical properties as well as the respectively set cold rolling degrees and strip thicknesses for the cold strips produced in the first test series from melts 1 to 16.
  • the hot strips produced from melts 1 to 16 in the manner described above were rewound at a reel temperature lower than 100 ° C, at 500 ° C, at 600 ° C and at 650 ° C.
  • the hot strips thus obtained were not intended for cold rolling, but have been supplied as hot strips - possibly after application of a metallic protective coating - the further processing to components.
  • Table 1 melt C Si Mn al Not a word Ti Cr B P S N 1 0.087 0.18 2.22 0,007 0,100 0,050 0.60 0.001 0,007 0,004 0.0045 2 0,069 0.28 2.62 0.04 0.092 0,080 0.58 0.0015 0,008 0.0015 0.0031 3 0,095 0.23 2.27 0.031 0.10 0,075 0.62 0.0012 0,013 0,002 0.0051 4 0,089 0.22 2.31 0.034 0,050 0.081 0.64 0.0017 0,012 0.0021 0.0036 5 0.091 0.31 2.52 0.034 0,150 0,052 0.42 0.0011 0.009 0,003 0.0046 6 0,060 0.26 2.15 0,041 0,250 0,051 0.25 0.001 0,012 0.0019 0.0052 7 0,102 0.15 2.26 0,038 0,050 0,090 0.80 0.0018 0.009 0.0021 0.0049 8th 0,065 0.60 2.64 0.032 0,095 0,025 0.45 0.0012 0,0

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Heat Treatment Of Steel (AREA)
  • Coating With Molten Metal (AREA)

Abstract

Dual-phase steel comprises 20-70% of martensite, up to 8% of residual austenite and balance of ferrite and/or bainite and which possess a tensile strength of at least 950 MPa, and composition of e.g. manganese (2.1-2.8 wt.%), chromium (0.2-0.8 wt.%), titanium (0.02-0.10 wt.%), boron (less than 0.002 wt.%), molybdenum (less than 0.25 wt.%), aluminum (less than 0.1 wt.%), copper (up to 0.2 wt.%), nickel (up to 0.1 wt.%), calcium (up to 0.005 wt.%), phosphorus (up to 0.2 wt.%), sulfur (up to 0.01 wt.%), nitrogen (up to 0.012 wt.%) and balance of iron and unavoidable contamination. Dual-phase steel comprises 20-70% of martensite, up to 8% of residual austenite and balance of ferrite and/or bainite and which possess a tensile strength of at least 950 MPa, and composition of carbon (0.050-0.105 wt.%), silicon (0.2-0.6 wt.%), manganese (2.1-2.8 wt.%), chromium (0.2-0.8 wt.%), titanium (0.02-0.10 wt.%), boron (less than 0.002 wt.%), molybdenum (less than 0.25 wt.%), aluminum (less than 0.1 wt.%), copper (up to 0.2 wt.%), nickel (up to 0.1 wt.%), calcium (up to 0.005 wt.%), phosphorus (up to 0.2 wt.%), sulfur (up to 0.01 wt.%), nitrogen (up to 0.012 wt.%) and balance of iron and unavoidable contamination. Independent claims are included for: (1) a flat product comprising the dual-phase steel; (2) production of a hot laminated strip with a tensile strength of at least 950 MPa and a dual phase structure, comprising melting the dual-phase steel, pouring the melt to a preproduct such as slab or thin slab, reheating or holding the preproduct at a hot rolling starting temperature of 1100-1300[deg] C, hot rolling the preproduct at a hot rolling temperature of 800-950[deg] C to the hot laminated strip and winding the hot laminated strip at a winder temperature of up to 650[deg] C, preferably 500-650[deg] C; and (3) production of a cold strip with a tensile strength of at least 950 MPa and a dual phase structure, comprising melting the composite dual-phase steel, pouring the melt to a preproduct such as slab or thin slab, reheating or holding the preproduct at a hot rolling starting temperature of 1100-1300[deg] C, hot rolling the preproduct at a hot rolling temperature of 800-950[deg] C to the hot laminated strip, winding the hot laminated strip at a winder temperature of up to 650[deg] C, preferably 500-650[deg] C, cold rolling the hot laminated strip to a cold strip, tempering the cold strip to a tempering temperature of 700-900[deg] C and controlled cooling of the tempered cold strip.

Description

Die Erfindung betrifft einen Dualphasenstahl, dessen Gefüge im Wesentlichen aus Martensit und Ferrit bzw. Bainit besteht, wobei Anteile an Restaustenit vorhanden sein können und der Dualphasenstahl eine Zugfestigkeit von mehr als 950 MPa aufweist. Ebenso betrifft die Erfindung ein aus einem solchen Dualphasenstahl hergestelltes Flachprodukt sowie ein Verfahren zur Herstellung eines Flachprodukts. Unter den Oberbegriff "Flachprodukt" fallen dabei typischerweise Stahlbänder und -bleche der erfindungsgemäßen Art.The invention relates to a dual-phase steel, the structure of which consists essentially of martensite and ferrite or bainite, wherein shares of retained austenite may be present and the dual-phase steel has a tensile strength of more than 950 MPa. The invention likewise relates to a flat product produced from such a dual-phase steel and to a process for producing a flat product. The generic term "flat product" typically includes steel strips and sheets of the type according to the invention.

Gerade im Bereich des Fahrzeugkarosseriebaus besteht die Forderung nach Stählen, die einerseits bei geringem Gewicht eine hohe Festigkeit, andererseits jedoch auch eine gute Verformbarkeit besitzen. Es sind eine große Zahl von Versuchen bekannt, Stähle zu erzeugen, die diese an sich widersprüchlichen Eigenschaften in sich vereinen.Especially in the field of vehicle bodyworking, there is a demand for steels which on the one hand have high strength on the one hand with low weight, but on the other hand also have good deformability. There are a large number of attempts known to produce steels that combine these self-contradictory properties.

So sind beispielsweise aus der EP 1 637 618 A1 ein Stahl, der nicht nur gut tiefziehbar sein soll, sondern auch hohe Zugfestigkeiten besitzt, ein daraus hergestelltes Flachprodukt und ein Verfahren zu dessen Herstellung bekannt,. Der bekannte Stahl enthält neben Eisen und den unvermeidbaren Verunreinigungen (in Gew.-%) 0,05 - 0,3 % C, bis zu 1,5 % Si, 0, 01 - 3,0 % Mn, bis zu 0,02 % P, 0,02 % S, bis zu 0,01 % N und 0, 01 - 3,0 % Al. Der bekannte Stahl soll einen Restaustenit-Gehalt von maximal 7 % aufweisen und bei einer in diesem Dokument näher bestimmten Verteilung Mg-Ausscheidungen mit einem Partikeldurchmesser von 0,01 - 5,0 µm aufweisen. Der derart zusammengesetzte und beschaffene Stahl soll besonders gut verformbar sein und eine geringe Neigung zur Bruchbildung zeigen. Entscheidende Bedeutung kommt bei diesem Stand der Technik somit die Anwesenheit von Mg in der Legierung zu, das gemäß den in der EP 1 637 618 A1 enthaltenen Erklärungen wesentlich die Neigung zur Bruchbildung ("Delayed fracture") verhindert, die bei anderen bekannten Stählen vergleichbarer Zusammensetzung gegeben ist.For example, from the EP 1 637 618 A1 a steel which is not only good to be deep-drawable but also has high tensile strengths, a flat product made therefrom and a process for its production. The known steel contains, in addition to iron and the unavoidable impurities (in% by weight) 0.05-0.3% C, up to 1.5% Si, 0.01-0.3% Mn, up to 0.02 % P, 0.02% S, up to 0.01% N and 0, 01 - 3.0% Al. The known steel should have a retained austenite content of not more than 7% and have Mg precipitates with a particle diameter of 0.01-5.0 μm at a distribution determined in more detail in this document. The thus assembled and procured steel should be particularly well deformable and show a low tendency to breakage. Decisive importance in this prior art is thus the presence of Mg in the alloy, which according to the in the EP 1 637 618 A1 Explanations significantly inhibit the tendency for "delayed fracture"("delayedfracture") that exists in other known steels of comparable composition.

Optional kann der aus der EP 1 637 618 A1 bekannte Stahl zur weiteren Steigerung seiner Festigkeit neben anderen wahlweise zugegebenen Legierungselementen auch Gehalte an Cr und Mo von jeweils 0,005 - 5 Gew.-% sowie 0.0051 - 2 Gew.-% Cu enthalten, wobei die Gehalte an Cu zusätzlich die Gefahr von Bruchbildung senken sollen.Optionally, the from the EP 1 637 618 A1 known steel to further increase its strength in addition to other optionally added alloying elements also contain contents of Cr and Mo of 0.005 - 5 wt .-% and 0.0051 - 2 wt .-% Cu, the contents of Cu should additionally reduce the risk of breakage ,

Eine weitere Möglichkeit der Erzeugung von aus höherfesten Dualphasenstählen bestehenden Flachprodukten, die auch nach Durchlauf eines Glühprozesses unter Einschluss einer Überalterungsbehandlung noch gute mechanisch-technologische Eigenschaften besitzen, ist aus der EP 1 200 635 A1 bekannt. Bei dem aus dieser Druckschrift bekannt Verfahren wird ein Stahlband oder -blech erzeugt, welches ein überwiegend ferritischmartensitisches Gefüge aufweist, an welchem der Martensitanteil zwischen 4 bis 20 % beträgt, wobei das Stahlband oder -blech neben Fe und erschmelzungsbedingten Verunreinigungen (in Gew.-%) 0,05 - 0,2 % C, bis zu 1,0 % Si, bis zu 2,0 % Mn, bis zu 0,1 % P, bis zu 0,015 % S, 0,02 - 0,4 % Al, bis zu 0,005 % N, 0,25 - 1,0 % Cr, 0,002 - 0,01 % B enthält. Vorzugsweise beträgt dabei der Martenistanteil des betreffenden Stahls rund 5 % bis 20 % des überwiegend martensitisch-ferritischen Gefüges. Ein solcherart erzeugtes Flachprodukt weist Festigkeiten von mindestens 500 N/mm2 bei gleichzeitig gutem Umformvermögen auf, ohne dass dazu besonders hohe Gehalte an bestimmten Legierungselementen erforderlich sind.Another possibility of producing high-strength dual-phase steels flat products, which still have good mechanical and technological properties even after passing through an annealing process including an overaging treatment, is from the EP 1 200 635 A1 known. In the process known from this document, a steel strip or sheet is produced which has a predominantly ferritic-martensitic microstructure in which the martensite fraction is between 4 and 20%, the steel strip or sheet containing Fe and melt-caused impurities (in% by weight). ) 0.05-0.2% C, up to 1.0% Si, up to 2.0% Mn, up to 0.1% P, up to 0.015% S, 0.02-0.4% Al, up to 0.005% N, 0.25-1.0% Cr, 0.002 - 0.01% B contains. Preferably, the Martenistanteil of the steel in question is about 5% to 20% of the predominantly martensitic-ferritic microstructure. A flat product produced in this way has strengths of at least 500 N / mm 2 and at the same time good formability, without requiring particularly high contents of certain alloying elements.

Zur Steigerung der Festigkeit ist bei dem in der EP 1 200 635 A1 beschriebenen Stahl auf den umwandlungsbeeinflussenden Effekt des Elementes Bor zurückgegriffen worden. Dessen festigkeitssteigernde Wirkung wird bei dem bekannten Stahl dadurch sichergestellt, dass dem Stahlwerkstoff mindestens ein alternativer Nitridbildner, vorzugsweise Al und ergänzend Ti, beigegeben wird. Die Wirkung der Zugabe an Titan und Aluminium besteht darin, dass sie den im Stahl enthaltenen Stickstoff binden, so dass Bor zur Bildung von härtesteigernden Karbiden zur Verfügung steht. Unterstützt durch den notwendig vorhandenen Cr-Gehalt wird auf diese Weise ein höheres Festigkeitsniveau erreicht als bei vergleichbaren Stählen. Jedoch liegt das Maximum der Festigkeit der in der EP 1 200 635 A1 beispielhaft angegebenen Stähle jeweils unterhalb von 900 MPa.To increase the strength is in the in the EP 1 200 635 A1 described steel has been resorted to the conversion-influencing effect of the element boron. Its strength-increasing effect is ensured in the known steel in that at least one alternative nitride former, preferably Al and additionally Ti, is added to the steel material. The effect of the addition of titanium and aluminum is that they bind the nitrogen contained in the steel, so that boron is available for the formation of hardness-increasing carbides. Supported by the necessary Cr content, a higher strength level is achieved in this way than with comparable steels. However, the maximum of the strength lies in the EP 1 200 635 A1 Steels exemplified below 900 MPa.

JP-A- 2000282 175 offenbart einen Stahl, dessen Gefüge besteht aus 60-90 vol.% Bainite und als Rest aus Ferrit, Martensit und Restaustenit für Karosserienbau. JP-A-2000282175 discloses a steel, the structure of which consists of 60-90 vol.% Bainite and the remainder of ferrite, martensite and retained austenite for bodywork.

Vor dem Hintergrund des voranstehend beschriebenen Standes der Technik lag der Erfindung die Aufgabe zu Grunde, einen Stahl und ein daraus hergestelltes Flachprodukt zu entwickeln, das eine Festigkeit von mindestens 950 MPa und eine gute Verformbarkeit aufweist. Darüber hinaus sollte der Stahl eine Oberflächenbeschaffenheit besitzen, die es unter Anwendung eines einfachen Herstellverfahrens erlaubt, ein aus diesem Stahl erzeugtes Flachprodukt im unbeschichteten oder mit einem vor Korrosion schützenden Überzug versehenen Zustand zu einem komplex geformten Bauteil, wie einem Teil einer Automobilkarosserie, zu verformen. Des Weiteren sollte auch ein Verfahren angegeben werden, dass es auf einfache Weise erlaubt, in der voranstehend genannten Weise beschaffene Flachprodukte herzustellen.Against the background of the prior art described above, the object of the invention was to develop a steel and a flat product produced therefrom which has a strength of at least 950 MPa and good deformability. In addition, the steel should be one Having a surface finish that allows using a simple manufacturing process, a flat product produced from this steel in the uncoated or provided with a corrosion-protective coating state to deform a complex-shaped component, such as a part of an automobile body. Furthermore, a method should also be given that allows in a simple manner to produce in the above-mentioned manner manufactured flat products.

In Bezug auf den Werkstoff ist diese Aufgabe erfindungsgemäß durch den in Anspruch 1 angegebenen Dualphasenstahl gelöst worden. Vorteilhafte Ausgestaltungen dieses Stahls sind in den auf Anspruch 1 rückbezogenen Ansprüchen genannt.With respect to the material, this object has been achieved by the dual-phase steel specified in claim 1. Advantageous embodiments of this steel are mentioned in the dependent claims on claim 1.

Ein die voranstehend genannte Aufgabe lösendes Flachprodukt ist entsprechend Anspruch 21 erfindungsgemäß dadurch gekennzeichnet, dass es aus einem erfindungsgemäß zusammengesetzten und beschaffenen Stahl besteht.A the above-mentioned object solving flat product according to claim 21 according to the invention, characterized in that it consists of a composite according to the invention and procured steel.

In Bezug auf das Herstellverfahren ist die oben genannte Aufgabe schließlich erfindungsgemäß durch die in den Ansprüchen 27 und 28 angegebenen Herstellweisen gelöst worden, wobei sich das in Anspruch 27 angegebene Verfahren auf die erfindungsgemäße Herstellung eines Warmbands und die in Anspruch 28 angegebene Vorgehensweise sich auf die erfindungsgemäße Herstellung eines Kaltbands beziehen. In den auf die Ansprüche 27 und 28 rückbezogenen Ansprüchen sind jeweils vorteilhafte Varianten der erfindungsgemäßen Verfahren enthalten. Zusätzlich sind nachfolgend für die praktische Anwendung der erfindungsgemäßen Verfahren und ihrer in den Ansprüchen angegebenen Varianten besonders vorteilhafte Ausgestaltungen erläutert.With regard to the manufacturing process, the above-mentioned object has finally been achieved according to the invention by the manufacturing methods specified in claims 27 and 28, wherein the method specified in claim 27 on the inventive production of a hot strip and the procedure specified in claim 28 is based on the invention Obtain production of a cold-rolled strip. The claims referring back to claims 27 and 28 each contain advantageous variants of the inventive method. In addition, for the practical application of the inventive method and their in the Claims specified variants particularly advantageous embodiments explained.

Ein erfindungsgemäßer Stahl zeichnet sich durch hohe Festigkeiten von mindestens 950, insbesondere 980 MPa, aus, wobei regelmäßig Festigkeiten von 1000 MPa und mehr erreicht werden. Gleichzeitig besitzt der erfindungsgemäße Stahl eine Streckgrenze von mindestens 580 MPa, insbesondere mindestens 600 MPa, und weist eine Dehnung A80 von mindestens 10 % auf.A steel according to the invention is characterized by high strengths of at least 950, in particular 980 MPa, with regular strengths of 1000 MPa and more being achieved. At the same time, the steel according to the invention has a yield strength of at least 580 MPa, in particular at least 600 MPa, and has an elongation A 80 of at least 10%.

Aufgrund der Kombination aus hoher Festigkeit und guter Verformbarkeit eignet sich erfindungsgemäßer Stahl insbesondere zur Herstellung von komplex geformten, im praktischen Einsatz hoch belasteten Bauteilen, wie sie beispielsweise im Bereich des Karosseriebaus für Automobile benötigt werden.Due to the combination of high strength and good deformability, steel according to the invention is particularly suitable for the production of complex shaped, highly loaded in practical use components, such as those required in the field of bodywork for automobiles.

Die vorteilhafte Eigenschaftskombination eines erfindungsgemäßen Stahls wird unter anderem dadurch erreicht, dass er trotz seiner hohen Festigkeiten ein Dualphasengefüge besitzt. So ist die Legierung eines erfindungsgemäßen Stahls so zusammengesetzt, dass er einen Martensitanteil von mindestens 20 % bis maximal 70 % besitzt. Gleichzeitig können Restaustenitanteile von bis zu 8 % vorteilhaft sein, wobei in der Regel geringere Restaustenitanteile von maximal 7 % oder darunter bevorzugt werden. Der Rest des Gefüges eines erfindungsgemäßen Dualphasenstahls besteht jeweils aus Ferrit und / oder Bainit (bainitischer Ferrit + Karbide).The advantageous combination of properties of a steel according to the invention is achieved inter alia by possessing a dual-phase structure despite its high strengths. Thus, the alloy of a steel according to the invention is composed to have a martensite content of at least 20% to a maximum of 70%. At the same time, residual austenite contents of up to 8% may be advantageous, with generally lower residual austenite contents of not more than 7% or less being preferred. The remainder of the microstructure of a dual-phase steel according to the invention consists respectively of ferrite and / or bainite (bainitic ferrite + carbides).

Die hohen Festigkeiten, guten Dehnungseigenschaften und optimierten Oberflächenbeschaffenheiten sind durch die erfindungsgemäße Einstellung des Dualphasengefüges erzielt worden. Diese ist durch eine enge Auswahl der einzelnen Gehalte an den Legierungselementen ermöglicht worden, die in einem erfindungsgemäßen Stahl neben Eisen und unvermeidbaren Verunreinigungen vorhanden sind.The high strengths, good elongation properties and optimized surface textures are due to the adjustment of the dual-phase structure according to the invention achieved. This has been made possible by a narrow selection of the individual contents of the alloying elements present in a steel according to the invention besides iron and unavoidable impurities.

So sieht die Erfindung einen C-Gehalt von 0,050 - 0,105 Gew.-% vor. Dabei sind die erfindungsgemäß vorgesehenen Gehalte an C im Hinblick auf eine möglichst gute Schweißbarkeit des Stahls gewählt worden. Besonders sicher kann die vorteilhafte Wirkung von Kohlenstoff in einem erfindungsgemäßen Stahl genutzt werden, wenn der C-Gehalt eines erfindungsgemäßen Stahls 0,060 - 0,090 Gew.-%, insbesondere 0,070 - 0,080 Gew.-%, beträgt.Thus, the invention provides a C content of 0.050-0.105% by weight. In this case, the inventively provided levels of C have been chosen in view of the best possible weldability of the steel. The advantageous effect of carbon in a steel according to the invention can be used particularly reliably if the C content of a steel according to the invention is 0.060-0.090% by weight, in particular 0.070-0.080% by weight.

Si dient in einem erfindungsgemäßen Stahl zur Steigerung der Festigkeit durch Härtung des Ferrits bzw. Bainits. Um diesen Effekt nutzen zu können, ist ein Mindestgehalt an Si von 0,10 Gew.-% vorgesehen, wobei die Wirkung von Si dann besonders sicher eintritt, wenn der Si-Gehalt eines erfindungsgemäßen Stahls mindestens 0,2 Gew.-%, insbesondere mindestens 0,25 Gew.-% beträgt. Auch ist bei Einhaltung dieser Obergrenze die Gefahr von Korngrenzoxidation minimiert. Im Hinblick darauf, dass ein aus einem erfindungsgemäßen Stahl erzeugtes Flachprodukt eine für die weitere Verarbeitung und erforderlichenfalls aufgetragene Beschichtungen optimale Oberflächenbeschaffenheit besitzen soll, ist gleichzeitig die Obergrenze des Si-Gehaltes auf 0,6 Gew.-% festgelegt worden. Dabei lässt sich ein ungünstiger Einfluss von Si auf die Eigenschaften des erfindungsgemäßen Stahls dadurch mit noch größerer Sicherheit vermeiden, dass der Si-Gehalt des erfindungsgemäßen Stahls auf 0,4 Gew.-%, insbesondere 0,35 Gew.-%, beschränkt wird.Si is used in a steel according to the invention to increase the strength by hardening the ferrite or bainite. To be able to use this effect, a minimum content of Si of 0.10 wt .-% is provided, the effect of Si is particularly safe when the Si content of a steel according to the invention at least 0.2 wt .-%, in particular at least 0.25 wt .-% is. Also, adherence to this upper limit minimizes the risk of grain boundary oxidation. In view of the fact that a flat product produced from a steel according to the invention should have an optimum surface finish for further processing and, if necessary, applied coatings, the upper limit of the Si content has at the same time been set at 0.6% by weight. In this case, an unfavorable influence of Si on the properties of the steel according to the invention can be avoided with even greater certainty that the Si content of the steel according to the invention is limited to 0.4% by weight, in particular 0.35% by weight.

Der Mn-Gehalt eines erfindungsgemäßen Stahls liegt im Bereich von 2,10 - 2,80 Gew.-%, um einerseits die festigkeitssteigernde Wirkung und andererseits den positiven Einfluss von Mn auf die Martensitbildung zu nutzen. Im Falle der erfindungsgemäßen Herstellung von Kaltband wirkt Mn sich zudem positiv im Hinblick auf die Absenkung der kritischen Abkühlgeschwindigkeit nach dem Glühen aus, da es die Entstehung von Perlit behindert. Die positiven Effekte der Anwesenheit von Mn in einem erfindungsgemäßen Stahl lassen sich dabei dann besonders sicher nutzen, wenn der Mn-Gehalt mindestens 2,20 Gew.-%, insbesondere mindestens 2,45 Gew.-% beträgt. Negative Einflüsse von Mn auf einen erfindungsgemäßen Stahl, wie beispielsweise eine Herabsetzung der Dehnung, Verschlechterung der Schweißeignung oder schlechtere Eignung zur Feuerverzinkung, können dadurch mit erhöhter Sicherheit ausgeschlossen werden, dass der Mn-Gehalt auf 2,70 Gew.-%, insbesondere 2,60 Gew.-%, beschränkt wird.The Mn content of a steel according to the invention is in the range of 2.10-2.80% by weight in order to use, on the one hand, the strength-increasing effect and, on the other hand, the positive influence of Mn on martensite formation. In the case of the production of cold strip according to the invention, Mn also has a positive effect with regard to the lowering of the critical cooling rate after annealing, since it hinders the formation of perlite. The positive effects of the presence of Mn in a steel according to the invention can be used with particular certainty if the Mn content is at least 2.20% by weight, in particular at least 2.45% by weight. Negative effects of Mn on a steel according to the invention, such as a reduction in elongation, deterioration of weldability or poorer suitability for hot-dip galvanizing, can be excluded with increased certainty that the Mn content to 2.70 wt .-%, in particular 2, 60 wt .-% is limited.

Cr wirkt in einem erfindungsgemäßen Dualphasenstahl in Gehalten von 0,2 - 0,8 Gew.-% ebenfalls festigkeitssteigernd. In Bezug auf die kritische Abkühlgeschwindigkeit nach dem Glühen eines aus erfindungsgemäßem Stahl hergestellten Kaltbands ist die Wirkung von Cr mit der Wirkung von Mn vergleichbar. Die vorteilhaften Effekte von Cr treten insbesondere dann ein, wenn der Cr-Gehalt mindestens 0,3 Gew.-%, insbesondere mindestens 0,55 Gew.-% beträgt. Gleichzeitig ist der Cr-Gehalt eines erfindungsgemäßen Stahls jedoch auf 0,8 Gew.-% beschränkt, um die Gefahr des Auftretens von Korngrenzenoxidation zu vermindern und einen negativen Einfluss auf die Dehnbarkeit des erfindungsgemäßen Stahls zu vermeiden. Dies wird insbesondere dann sichergestellt, wenn die Obergrenze des Chrom-Gehalts eines erfindungsgemäßen Stahls auf höchstens 0,7 Gew.-%, insbesondere 0,65 Gew.-%, festgesetzt wird.Cr also strengthens in a dual-phase steel according to the invention in contents of 0.2-0.8% by weight. With respect to the critical cooling rate after the annealing of a cold strip made of steel according to the invention, the effect of Cr is comparable to the effect of Mn. The advantageous effects of Cr occur in particular when the Cr content is at least 0.3% by weight, in particular at least 0.55% by weight. At the same time, however, the Cr content of a steel according to the invention is limited to 0.8% by weight in order to reduce the risk of occurrence of grain boundary oxidation and to avoid a negative influence on the ductility of the steel according to the invention. This is especially ensured when the upper limit of the Chromium content of a steel according to the invention to at most 0.7 wt .-%, in particular 0.65 wt .-%, is set.

Die Anwesenheit von Titan in Gehalten von mindestens 0,02 Gew.-% trägt ebenfalls zur Steigerung der Festigkeit eines erfindungsgemäßen Stahls bei, indem es feine Ausscheidungen von TiC bzw. Ti(C,N) bildet und zur Kornfeinung beiträgt. Eine weitere positive Wirkung von Ti besteht in der Abbindung eventuell vorhandenen Stickstoffs, so dass die Bildung von Bornitriden im erfindungsgemäßen Stahl verhindert wird. Diese hätten einen stark negativen Einfluss auf die Dehnungseigenschaften und damit einhergehend auf die Umformbarkeit eines erfindungsgemäßen Flachproduktes. Durch die Anwesenheit von Ti wird somit im Fall einer Zugabe von Bor zur Festigkeitssteigerung auch sichergestellt, dass das Bor seine Wirkung voll entfalten kann. Zu diesem Zweck kann es günstig sein, wenn Ti in einer Menge zugegeben wird, die mehr als das 5,1-fache des jeweiligen N-Gehaltes beträgt (d. h. Ti-Gehalt > 1,5 (3,4 x N-Gehalt)). Zu hohe Ti-Gehalte führen allerdings zu ungünstig hohen Rekristallisationstemperaturen, was sich insbesondere dann negativ auswirkt, wenn aus erfindungsgemäßem Stahl kaltgewalzte Flachprodukte erzeugt werden, die abschließend geglüht werden. Daher ist die Obergrenze des Ti-Gehalts auf 0,10 Gew.-% beschränkt worden. Besonders sicher lässt sich der positive Einfluss von Ti auf die Eigenschaften eines erfindungsgemäßen Stahls nutzen, wenn sein Ti-Gehalt 0,060 - 0,090 Gew.-%, insbesondere 0,070 - 0,085 Gew.-%, beträgt.The presence of titanium at levels of at least 0.02% by weight also contributes to increasing the strength of a steel according to the invention by forming fine precipitates of TiC or Ti (C, N) and contributing to grain refining. Another positive effect of Ti is the setting of possibly present nitrogen, so that the formation of boron nitrides in the steel according to the invention is prevented. These would have a strong negative impact on the elongation properties and, consequently, on the formability of a flat product according to the invention. The presence of Ti thus ensures, in the case of an addition of boron to increase the strength, that the boron can fully develop its effect. For this purpose, it may be favorable if Ti is added in an amount which is more than 5.1 times the respective N content (ie Ti content> 1.5 (3.4 × N content)). , However, too high Ti contents lead to unfavorably high recrystallization temperatures, which has a negative effect, in particular, when cold-rolled flat products are produced from steel according to the invention, which are finally annealed. Therefore, the upper limit of the Ti content has been limited to 0.10 wt%. The positive influence of Ti on the properties of a steel according to the invention can be used particularly reliably if its Ti content is 0.060-0.090% by weight, in particular 0.070-0.085% by weight.

Auch durch die erfindungsgemäß optional vorgesehenen Gehalte an B von bis zu 0,002 Gew.-% wird die Festigkeit des erfindungsgemäßen Stahls erhöht und, wie durch die jeweilige Zugabe von Mn, Cr und Mo, im Falle der Herstellung von Kaltband aus erfindungsgemäßem Stahl die kritische Abkühlgeschwindigkeit nach dem Glühen herabgesetzt. Deshalb beträgt gemäß einer besonders bevorzugten Ausgestaltung der Erfindung der B-Gehalt mindestens 0,0005 Gew.-%. Gleichzeitig können jedoch zu hohe Gehalte an B die Verformbarkeit des erfindungsgemäßen Stahls herabsetzen und die Ausprägung des erfindungsgemäß angestrebten Dualphasengefüges negativ beeinflussen. Optimierte Wirkungen von Bor lassen sich in einem erfindungsgemäßen Stahl dadurch nutzen, dass der B-Gehalt auf 0,0007 - 0,0016 Gew.-%, insbesondere 0,0008 - 0,0013 Gew.-%, beschränkt wird.The strength of the steel according to the invention is also increased by the amounts of B, which are optionally provided according to the invention, of up to 0.002% by weight and, as in the case of the addition of Mn, Cr and Mo in the case of the production of cold strip of steel according to the invention, the critical cooling rate lowered after annealing. Therefore, according to a particularly preferred embodiment of the invention, the B content is at least 0.0005 wt .-%. At the same time, however, excessively high contents of B can reduce the deformability of the steel according to the invention and adversely affect the expression of the dual-phase structure desired according to the invention. Optimized effects of boron can be used in a steel according to the invention in that the B content is limited to 0.0007-0.0016% by weight, in particular 0.0008-0.0013% by weight.

Wie Bor oder Cr in den voranstehend genannten Gehaltsbereichen tragen auch die erfindungsgemäß wahlweise vorhandenen Gehalte an Molybdän von mindestens 0,05 Gew.-% zur Erhöhung der Festigkeit eines erfindungsgemäßen Stahls bei. Dabei wirkt sich die Anwesenheit von Mo erfahrungsgemäß nicht negativ auf die Beschichtbarkeit des Flachproduktes mit einer metallischen Beschichtung und seiner Dehnbarkeit aus. Praktische Versuche haben gezeigt, dass sich die positiven Einflüsse von Mo bis zu Gehalten von 0,25 Gew.-%, insbesondere 0,22 Gew.-%, auch unter Kostengesichtspunkten besonders effektiv nutzen lassen. So wirken sich bereits Gehalte an Mo von mindestens 0,05 Gew.-% positiv auf die Eigenschaften eines erfindungsgemäßen Stahls aus. Bei Anwesenheit ausreichender Mengen an anderen festigkeitssteigernden Elementen tritt die erwünschte Wirkung von Molybdän in einem erfindungsgemäßen Stahl insbesondere dann ein, wenn sein Mo-Gehalt 0,065 - 0,18 Gew.-%, insbesondere 0,08 - 0,13 Gew.-%, beträgt. Insbesondere dann jedoch, wenn Cr-Gehalte von weniger als 0,3 Gew.-% im erfindungsgemäßen Stahl vorhanden sind, ist es vorteilhaft, zur Sicherung der geforderten Festigkeit des erfindungsgemäßen Stahls 0,05 - 0,22 Gew.-% Mo zuzugeben.Like boron or Cr in the above-mentioned content ranges, the inventively optional contents of molybdenum of at least 0.05% by weight also contribute to increasing the strength of a steel according to the invention. Experience has shown that the presence of Mo does not adversely affect the coatability of the flat product with a metallic coating and its ductility. Practical experiments have shown that the positive effects of Mo up to contents of 0.25% by weight, in particular 0.22% by weight, can be used particularly effectively, even from a cost point of view. For example, contents of Mo of at least 0.05% by weight have a positive effect on the properties of a steel according to the invention. In the presence of sufficient amounts of other strength enhancing elements, the desired effect of molybdenum occurs a steel according to the invention, in particular if its Mo content is 0.065-0.18% by weight, in particular 0.08-0.13% by weight. In particular, however, if Cr contents of less than 0.3% by weight are present in the steel according to the invention, it is advantageous to add 0.05-0.22% by weight of Mo to secure the required strength of the steel according to the invention.

Aluminium wird bei der Erschmelzung eines erfindungsgemäßen Stahls zur Desoxidation und zum Abbinden von gegebenenfalls in dem Stahl enthaltenem Stickstoff genutzt. Zu diesem Zweck kann dem erfindungsgemäßen Stahl erforderlichenfalls Al in Gehalten von weniger als < 0,1 Gew.-% zugegeben werden, wobei die gewünschte Wirkung von Al dann besonders sicher eintritt, wenn dessen Gehalte im Bereich von 0,01 - 0,06 Gew.-%, insbesondere 0,020 - 0,050 Gew.-%, liegen.Aluminum is used in the melting of a steel according to the invention for deoxidizing and for setting nitrogen which may be present in the steel. For this purpose, if necessary, Al may be added to the steel according to the invention in contents of less than <0.1% by weight, the desired effect of Al occurring particularly safely if its contents in the range of 0.01-0.06 wt .-%, in particular 0.020 - 0.050 wt .-%, are.

Der erfindungsgemäße Stahl kann zur weiteren Steigerung seiner Festigkeit Kupfer in Gehalten bis zu 0,20 Gew.-% aufweisen. Besonders günstig wirkt sich ein Kupfergehalt dabei dann aus, wenn er im Bereich von 0,08 - 0,12 Gew.-% liegt.The steel according to the invention may, to further increase its strength, have copper in contents of up to 0.20% by weight. A copper content has a particularly favorable effect when it is in the range of 0.08 to 0.12 wt .-%.

Ebenso kann bis zu 0,1 Gew.-% Nickel dem erfindungsgemäßen Stahl zugegeben werden, um die Härtbarkeit und dementsprechend die Festigkeit eines erfindungsgemäßen Stahls weiter zu verbessern.Likewise, up to 0.1% by weight of nickel may be added to the steel according to the invention in order to further improve the hardenability and, accordingly, the strength of a steel according to the invention.

Ca kann wie Al bei der Stahlerzeugung zur Desoxidation verwendet werden. Darüber hinaus kann die Anwesenheit von Ca in Gehalten von bis zu 0,005 Gew.-%, insbesondere von 0,002 - 0,004 Gew.-%, auch die Entstehung eines feinkörnigen Gefüges begünstigen.Ca can be used for deoxidation like Al in steelmaking. In addition, the presence of Ca in amounts of up to 0.005 wt .-%, in particular from 0.002 to 0.004 wt .-%, also favor the formation of a fine-grained structure.

Stickstoff ist in erfindungsgemäßem Stahl nur in Gehalten von bis zu 0,012 Gew.-% zugelassen, um insbesondere bei gleichzeitiger Anwesenheit von B die Bildung von Bornitriden zu vermeiden. Um sicher zu verhindern, dass das jeweils vorhandene Titan vollständig mit N abgebunden wird und nicht mehr als Mikrolegierungselement wirksam sein kann, ist der N-Gehalt bevorzugt auf 0,007 Gew.-% beschränkt.Nitrogen is allowed in inventive steel only in amounts of up to 0.012 wt .-%, in order to avoid the formation of boron nitrides especially in the simultaneous presence of B. In order to reliably prevent the titanium present in each case from being completely set to N and can no longer be effective as a micro-alloying element, the N content is preferably limited to 0.007% by weight.

Niedrige, unterhalb der erfindungsgemäß vorgesehenen Obergrenze liegende P-Gehalte tragen zur guten Schweißbarkeit erfindungsgemäßen Stahls bei. Daher wird der P-Gehalt erfindungsgemäß bevorzugt auf < 0,1, insbesondere < 0,02 Gew.-% beschränkt, wobei besonders gute Ergebnisse bei Gehalten von weniger als 0,010 Gew.-% erzielt werden.Low P contents below the upper limit provided by the invention contribute to the good weldability of the steel according to the invention. Therefore, the P content is according to the invention preferably limited to <0.1, in particular <0.02 wt .-%, with particularly good results at levels of less than 0.010 wt .-% can be achieved.

Bei unterhalb der erfindungsgemäß vorgegebenen Obergrenze liegenden Gehalten an Schwefel wird die Bildung von MnS bzw. (Mn,Fe)S unterdrückt, so dass eine gute Dehnbarkeit des erfindungsgemäßen Stahls bzw. der daraus hergestellten Flachprodukte gewährleistet ist. Dies ist insbesondere dann der Fall, wenn der S-Gehalt unter 0,003 Gew.-% liegt.At below the inventively given upper limit levels of sulfur, the formation of MnS or (Mn, Fe) S is suppressed, so that a good extensibility of the steel according to the invention or the flat products produced therefrom is ensured. This is especially the case when the S-content is less than 0.003 wt .-%.

Zur erfindungsgemäßen Herstellung eines Warmbands mit einer Zugfestigkeit von mindestens 950 MPa und einem Dualphasengefüge, das zu 20 - 70 % aus Martensit, bis zu 8 % aus Restaustenit und als Rest aus Ferrit und/oder Bainit besteht, wird zunächst ein erfindungsgemäß zusammengesetzter Dualphasenstahl erschmolzen, dann die Schmelze zu einem Vorprodukt, wie Bramme oder Dünnbramme, vergossen, anschließend das Vorprodukt bei einer Warmwalzstarttemperatur von 1100 - 1300 °C wiedererwärmt oder gehalten, daraufhin das Vorprodukt bei einer Warmwalzendtemperatur von 800 - 950 °C zu einem Warmband warmgewalzt und schließlich das Warmband bei einer Haspeltemperatur von bis zu 650 °C, insbesondere 500 - 650 °C, gehaspelt.For the production according to the invention of a hot strip with a tensile strength of at least 950 MPa and a dual-phase structure consisting of 20-70% martensite, up to 8% retained austenite and the remainder ferrite and / or bainite, a dual phase steel composed according to the invention is first melted, then the melt to a precursor, such as slab or thin slab, cast, then reheated the precursor at a hot rolling start temperature of 1100 - 1300 ° C. or held, then the precursor hot rolled at a hot rolling end temperature of 800 - 950 ° C to a hot strip and finally the hot strip at a reel temperature of up to 650 ° C, in particular 500 - 650 ° C, reeled.

In erfindungsgemäßer Weise aus einem erfindungsgemäßen Dualphasenstahl bestehende Flachprodukte können als nach dem Warmwalzen erhaltenes Warmband unmittelbar, d. h. ohne nachfolgend durchgeführten Kaltwalzprozess, der weiteren Verarbeitung zugeführt werden. Dabei konnte nachgewiesen werden, dass erfindungsgemäß zusammengesetztes Warmband unempfindlich auf die Änderung der Haspeltemperatur reagiert und sich stets Festigkeiten, die im Bereich von 1000 MPa liegen, und Streckgrenzen von 750 bis 890 MPa erreichen lassen.In accordance with the invention from a dual-phase steel according to the invention existing flat products can be obtained as immediately after hot rolling hot strip, d. H. without subsequent cold rolling process, for further processing. It could be demonstrated that hot strip composed according to the invention reacts insensitive to the change in the coiler temperature and can always achieve strengths which are in the range of 1000 MPa and yield strengths of 750 to 890 MPa.

Ähnliche Eigenschaften werden auch bei Warmbändern erzielt, die aus Complex-Phasen-Stählen erzeugt werden. Allerdings verlangen diese eine besonders exakte Einstellung der Haspeltemperatur. So gilt für aus Complex-Phasen-Stahl erzeugte Warmbänder in der Praxis eine maximal zulässige Abweichung von der Haspeltemperatur von nur 30 °C.Similar properties are also achieved with hot strips made from complex phase steels. However, these require a particularly precise adjustment of the reel temperature. Thus, in practice, for hot strip produced from complex phase steel, a maximum permissible deviation from the reel temperature of only 30 ° C applies.

Bei erfindungsgemäß erzeugten Warmbändern bestehen derart hohe Anforderungen an die Genauigkeit der Prozessführung nicht. Stattdessen lässt sich bei der erfindungsgemäßen Erzeugung von Warmband die Haspeltemperatur über einen großen Bereich variieren, um die jeweils gewünschten Eigenschaften und Gefügeausprägungen gezielt zu beeinflussen. Für diesen Zweck besonders geeignete Haspeltemperaturen liegen im Bereich von 500 - 650 °C, wobei sich Haspeltemperaturen von 530 - 580 °C als besonders günstig erwiesen haben, da bei Temperaturen von mehr als 580 °C mit zunehmender Haspeltemperatur die Gefahr von Korngrenzoxidation steigt und bei unterhalb von 500 °C liegenden Haspeltemperaturen die Festigkeit des Warmbands so stark ansteigt, dass eine nachfolgende Verformung schwierig werden kann.In hot strips produced according to the invention, such high demands on the accuracy of the process control do not exist. Instead, in the production of hot strip according to the invention, the reel temperature can be varied over a wide range in order to influence the respective desired properties and microstructural characteristics in a targeted manner. For this purpose, particularly suitable reel temperatures are in the range of 500-650 ° C, with reel temperatures of 530-580 ° C as have proved particularly favorable, since at temperatures of more than 580 ° C with increasing reel temperature, the risk of grain boundary oxidation increases and lying below 500 ° C reel temperatures, the strength of the hot strip increases so much that a subsequent deformation can be difficult.

Aus erfindungsgemäß beschaffenem Warmband lassen sich sowohl im unbeschichteten als auch beschichteten Zustand hoch belastbare, komplex gestaltete Bauteile formen.From hot-rolled strip according to the invention, it is possible to form highly loadable, complex-shaped components both in the uncoated and coated state.

Soll das in erfindungsgemäßer Weise erhaltene Warmband unbeschichtet bleiben oder als Warmband elektrolytisch mit einem metallischen Überzug beschichtet werden, so ist keine Glühung des Flachproduktes erforderlich. Soll dagegen das Warmband durch Feuerverzinken mit einem metallischen Überzug beschichtet werden, so wird es zunächst bei einer maximalen Glühtemperatur von 600 °C geglüht und dann auf die Temperatur des Beschichtungsbades, bei dem es sich beispielsweise um ein Zinkbad handeln kann, abgekühlt. Nach dem Durchlauf des Zinkbades kann das beschichtete Warmband in konventioneller Weise auf Raumtemperatur abgekühlt werden.If the hot strip obtained in the manner according to the invention should remain uncoated or be electrolytically coated with a metallic coating as a hot strip, no annealing of the flat product is required. If, on the other hand, the hot-rolled strip is to be coated with a metallic coating by hot-dip galvanizing, then it is first annealed at a maximum annealing temperature of 600 ° C. and then cooled to the temperature of the coating bath, which may be, for example, a zinc bath. After passing through the zinc bath, the coated hot strip can be conventionally cooled to room temperature.

Werden Flachprodukte mit geringerer Dicke gefordert, so können aus zusammengesetztem Stahl auch Kaltbänder erzeugt werden. Bei einem zu diesem Zweck vorgesehenem erfindungsgemäßen Verfahren zum Herstellen eines Kaltbands mit einer Zugfestigkeit von mindestens 950 MPa und einem Dualphasengefüge, das zu 20 - 70 % aus Martensit, bis zu 8 % aus Restaustenit und als Rest aus Ferrit und/oder Bainit besteht, wird zunächst ein erfindungsgemäß zusammengesetzter Dualphasenstahl erschmolzen, dann die Schmelze zu einem Vorprodukt, wie Bramme oder Dünnbramme, vergossen, anschließend das Vorprodukt bei einer Warmwalzstarttemperatur von 1100 - 1300 °C wiedererwärmt oder gehalten, daraufhin das Vorprodukt bei einer Warmwalzendtemperatur von 800 - 950 °C zu einem Warmband warmgewalzt, das erhaltene Warmband bei einer Haspeltemperatur von bis zu 650 °C, insbesondere 500 - 650 °C, gehaspelt, daraufhin das Warmband zu einem Kaltband kaltgewalzt, anschließend das Kaltband bei einer 700 - 900 °C betragenden Glühtemperatur geglüht und schließlich das Kaltband kontrolliert abgekühlt.If flat products with a smaller thickness are required, cold rolled strips can also be produced from composite steel. In an intended for this purpose method for producing a cold strip having a tensile strength of at least 950 MPa and a dual-phase structure consisting of 20-70% martensite, up to 8% of retained austenite and the remainder of ferrite and / or bainite is first, a composite according to the invention dual-phase steel melted, then cast the melt into a precursor, such as slab or thin slab, then reheated or held the precursor at a hot rolling start temperature of 1100-1300 ° C, then the hot rolled at a final hot rolling temperature of 800-950 ° C to a hot strip, the pre-product obtained hot strip at a reel temperature of up to 650 ° C, in particular 500 - 650 ° C, reeled, then the hot strip cold rolled into a cold strip, then the cold strip annealed at a 700 - 900 ° C amount annealing temperature and finally cooled the cold strip controlled.

Das so erzeugte Kaltband kann ebenfalls mit einem vor Korrosion schützenden Überzug versehen werden.The cold strip thus produced can also be provided with a protective coating against corrosion.

Haspeltemperaturen im Bereich von bis zu 580 °C haben sich im Zusammenhang mit der Erzeugung von Kaltband als besonders vorteilhaft erwiesen, weil bei Überschreiten der Haspeltemperatur von 580 °C die Gefahr von Korngrenzoxidation ansteigt. Mit niedrigen Haspeltemperaturen steigt die Festigkeit und Streckgrenze des Warmbands an, so dass das Warmband immer schwerer kaltgewalzt werden kann. Dementsprechend wird das zu Kaltband kaltzuwalzende Warmband bevorzugt bei mindestens 500 °C, insbesondere mindestens 530 °C oder mindestens 550 °C, gehaspelt.Coiling temperatures in the range of up to 580 ° C have proven to be particularly advantageous in connection with the production of cold strip, because when exceeding the coiler temperature of 580 ° C, the risk of grain boundary oxidation increases. With low reel temperatures, the strength and yield strength of the hot strip increases, so that the hot strip can be cold rolled more and more difficult. Accordingly, the cold strip to be cold rolled to cold strip is preferably at least 500 ° C, in particular at least 530 ° C or at least 550 ° C, reeled.

Wird das Warmband zu Kaltband kaltgewalzt, so hat es sich als günstig erwiesen, wenn dabei Kaltwalzgrade eingestellt werden, die 40 - 70 %, insbesondere 50 - 60 %, betragen. Zu geringe Verformungsgrade sind im Hinblick auf die Gefahr von Grobkornbildung beim abschließenden Glühen ungünstig. Derart kaltgewalztes erfindungsgemäßes Kaltband weist typischerweise Dicken von 0, 8 - 2,5 mm auf.If the hot strip is cold rolled to cold strip, so it has proven to be beneficial if doing cold rolling degrees are set, which are 40 - 70%, in particular 50 - 60%. Too low a degree of deformation are unfavorable in view of the risk of coarse grain formation in the final annealing. Such cold-rolled Cold rolled strip according to the invention typically has thicknesses of 0, 8-2.5 mm.

Sofern das erfindungsgemäße Flachprodukt mit einem metallischen Schutzüberzug versehen wird, kann dies beispielsweise durch Feuerverzinken, eine Galvannealing-Behandlung oder elektrolytisches Beschichten erfolgen. Erforderlichenfalls kann dabei vor dem Beschichten eine Voroxidation durchgeführt werden, um eine sichere Anbindung der metallischen Beschichtung an das jeweils zu beschichtende Substrat zu gewährleisten.If the flat product according to the invention is provided with a metallic protective coating, this can be done, for example, by hot-dip galvanizing, galvannealing or electrolytic coating. If necessary, a pre-oxidation can be carried out before the coating in order to ensure a secure connection of the metallic coating to the respective substrate to be coated.

Wenn das erfindungsgemäß erzeugte Kaltband unbeschichtet bleiben oder elektrolytisch beschichtet werden soll, so erfolgt eine Glühbehandlung in einer Conti-Glühe als separater Arbeitsschritt. Die dabei erreichten maximalen Glühtemperaturen liegen im Bereich von 700 - 900 °C bei Aufheizraten von 1 - 50 K/s. Anschließend wird das geglühte Kaltband zur gezielten Einstellung der erfindungsgemäß angestrebten Eigenschaftskombination bevorzugt in der Weise abgekühlt, dass im Temperaturbereich von 550 - 650 °C Abkühlgeschwindigkeiten von mindestens 10 K/s erreicht werden, um die Bildung von Perlit zu unterdrücken. Nach Erreichen der in diesem kritischen Temperaturbereich liegenden Temperatur kann das Band für eine Dauer von 10 - 100 s gehalten werden oder direkt mit einer Abkühlrate von 0,5 - 30 K/s auf Raumtemperatur abgekühlt werden.If the cold strip produced according to the invention remains uncoated or is to be electrolytically coated, an annealing treatment in a continuous annealing anneal takes place as a separate working step. The maximum annealing temperatures achieved are in the range of 700-900 ° C at heating rates of 1-50 K / s. Subsequently, the annealed cold strip for the targeted setting of the desired property combination according to the invention is preferably cooled in such a way that in the temperature range of 550-650 ° C cooling rates of at least 10 K / s are achieved in order to suppress the formation of perlite. After reaching the temperature which is within this critical temperature range, the strip can be held for a period of 10-100 s or cooled directly to room temperature at a cooling rate of 0.5-30 K / s.

Wenn das Kaltband jedoch durch Feuerverzinken beschichtet werden soll, dann lassen sich die Arbeitsschritte des Glühens und des Beschichtens zusammenlegen. In diesem Fall durchläuft das Kaltband in kontinuierlicher Abfolge verschiedene Ofenabschnitte einer Feuerbeschichtungsanlage, wobei in den einzelnen Ofenabschnitten unterschiedliche Temperaturen herrschen, die im Maximum im Bereich von 700 - 900 °C liegen, wobei Aufheizraten im Bereich von 2 - 100 K/s gewählt werden sollten. Nach Erreichen der jeweiligen Glühtemperatur wird das Band dann für 10 - 200 s bei dieser Temperatur gehalten. Anschließend wird das Band auf die in der Regel unter 500 °C liegende Temperatur des jeweiligen Beschichtungsbades, bei dem es sich typischerweise um ein Zinkbad handelt, abgekühlt, wobei auch in diesem Fall im Temperaturbereich von 550 - 650 °C die Abkühlgeschwindigkeit mehr als 10 K/s betragen sollte. Optional kann das Kaltband nach Erreichen dieser Temperaturstufe für 10 - 100 s bei der jeweiligen Temperatur gehalten werden. Dann läuft das geglühte Kaltband durch das jeweilige Beschichtungsbad, bei dem es sich bevorzugt um ein Zinkbad handelt. Anschließend erfolgt entweder eine Abkühlung auf Raumtemperatur, um ein konventionell feuerverzinktes Kaltband zu erhalten, oder ein schnelles Aufheizen mit anschließender Abkühlung auf Raumtemperatur, um ein Galvanealed-Kaltband herzustellen.However, if the cold strip is to be coated by hot dip galvanizing, then the steps of annealing and coating can be combined. In this case, the cold strip in continuous sequence through different furnace sections of a fire-coating plant, wherein in the individual furnace sections have different temperatures, the maximum in the range of 700 - 900 ° C, with heating rates in the range of 2 - 100 K / s should be selected. After reaching the respective annealing temperature, the strip is then held at this temperature for 10-200 seconds. The strip is then cooled to the temperature of the respective coating bath, which is typically below 500 ° C., which is typically a zinc bath, the cooling rate also being more than 10 K in the temperature range 550-650 ° C. in this case / s should be. Optionally, after reaching this temperature level, the cold strip can be kept at the respective temperature for 10 - 100 s. Then the annealed cold strip passes through the respective coating bath, which is preferably a zinc bath. This is followed by either cooling to room temperature to obtain a conventionally hot-dip galvanized cold-rolled strip or rapid heating followed by cooling to room temperature to produce a galvanized cold-rolled strip.

Erforderlichenfalls kann das Kaltband im beschichteten oder unbeschichteten Zustand nach der Glühbehandlung einer Dressierwalzung unterzogen werden, bei der im Bereich von bis 2 % liegende Dressiergrade eingestellt werden.If necessary, the cold-rolled strip in the coated or uncoated state after the annealing treatment may be subjected to a skin pass rolling in which the skin passages ranging up to 2% are adjusted.

Nachfolgend wird die Erfindung anhand von Ausführungsbeispielen näher erläutert.The invention will be explained in more detail by means of exemplary embodiments.

Sechzehn Stahlschmelzen 1 - 16, deren Zusammensetzungen in Tabelle 1 angegeben sind, sind in konventioneller Weise erschmolzen und zu Brammen vergossen worden. Die Brammen sind anschließend in einem Ofen auf 1200 °C wiedererwärmt und ausgehend von dieser Temperatur in konventioneller Weise warmgewalzt worden. Die Walzendtemperatur betrug dabei 900 °C.Sixteen molten steels 1-16, the compositions of which are given in Table 1, were melted in a conventional manner and cast into slabs. The slabs are then reheated in an oven to 1200 ° C and from this temperature in hot-rolled conventionally. The rolling end temperature was 900 ° C.

Für eine erste Versuchsreihe sind die so erhaltenen Warmbänder bei einer mit einer Genauigkeit von +/- 30 °C eingestellten Haspeltemperatur von 550 °C gehaspelt worden, bevor sie mit einem Kaltwalzgrad von 50 %, 65 % bzw. 70 % zu Kaltband mit einer Dicke von 0,8 mm bis 2 mm kaltgewalzt worden sind.For a first series of tests, the hot rolled strips thus obtained were rewound at a coiler temperature of 550 ° C., adjusted to an accuracy of +/- 30 ° C., before being cold rolled to a thickness of 50%, 65% and 70%, respectively from 0.8 mm to 2 mm cold rolled.

In Tabelle 2 sind für die in der ersten Versuchsreihe aus den Schmelzen 1 bis 16 erzeugten Kaltbänder der Gefügezustand, die mechanischen Eigenschaften sowie die jeweils eingestellten Kaltwalzgrade und Banddicken angegeben.Table 2 shows the microstructural state, the mechanical properties as well as the respectively set cold rolling degrees and strip thicknesses for the cold strips produced in the first test series from melts 1 to 16.

In vier weiteren Versuchsreihen sind die aus den Schmelzen 1 bis 16 in der voranstehend beschriebenen Weise erzeugten Warmbänder bei einer weniger als 100 °C, bei einer 500 °C, bei einer 600 °C und bei einer 650 °C betragenden Haspeltemperatur gehaspelt worden. Die für diese Warmbänder ermittelten Eigenschaften sind in den Tabellen 3 (Haspeltemperatur 20 °C), 4 (Haspeltemperatur = 500 °C), 5 (Haspeltemperatur = 580 °C) und 6 (Haspeltemperatur = 650 °C) eingetragen. Die so erhaltenen Warmbänder waren nicht für das Kaltwalzen bestimmt, sondern sind als Warmbänder - ggf. nach Auftrag einer metallischen Schutzbeschichtung - der weiteren Verarbeitung zu Bauteilen zugeführt worden. Tabelle 1 Schmelze C Si Mn Al Mo Ti Cr B P S N 1 0,087 0,18 2,22 0,007 0,100 0,050 0,60 0,001 0,007 0,004 0,0045 2 0,069 0,28 2,62 0,04 0,092 0,080 0,58 0,0015 0,008 0,0015 0,0031 3 0,095 0,23 2,27 0,031 0,10 0,075 0,62 0,0012 0,013 0,002 0,0051 4 0,089 0,22 2,31 0,034 0,050 0,081 0,64 0,0017 0,012 0,0021 0,0036 5 0,091 0,31 2,52 0,034 0,150 0,052 0,42 0,0011 0,009 0,003 0,0046 6 0,060 0,26 2,15 0,041 0,250 0,051 0,25 0,001 0,012 0,0019 0,0052 7 0,102 0,15 2,26 0,038 0,050 0,090 0,80 0,0018 0,009 0,0021 0,0049 8 0,065 0,60 2,64 0,032 0,095 0,025 0,45 0,0012 0,014 0,0017 0,0039 9 0,063 0,16 2,10 0,035 0,240 0,063 0,71 0,0011 0,008 0,0021 0,0046 10 0,092 0,35 2,12 0,032 0,098 0,077 0,46 0,0017 0,013 0,003 0,0033 11 0,100 0,21 2,34 0,042 0,130 0,065 0,47 0,0018 0,014 0,0017 0,0032 12 0,072 0,50 2,65 0,031 0,160 0,089 0,32 0,0014 0,009 0,0021 0,005 13 0,076 0,34 2,39 0,037 0,200 0,057 0,54 0,0015 0,012 0,0015 0,0047 14 0,084 0,23 2,52 0,037 0,060 0,031 0,63 0,001 0,008 0,0033 0,0032 15 0,092 0,15 2,27 0,033 0,210 0,035 0,75 0,0013 0,014 0,0018 0,0041 16 * 0,083 0,05 2,20 0,032 0,170 0,070 0,80 0,0016 0,013 0,0018 0,0032 Angaben in Gew.-%, Rest Eisen und unvermeidbare Verunreinigungen
* Außer dem beanspruchten Gegenstand Tabelle 2 Schmelze Rp0.2 Rm A80 Gefüge Kaltwalzgrad Dicke Matrix Martensit Restaustenit [MPa] [%] [%] [%] [%] [mm] 1 601 980 14,8 Ferrit/Bainit 35 - 40 3 50 2 2 659 1038 15,9 Bainit/Ferrit 40 - 50 2 50 2 3 621 1012 14,6 Bainit/Ferrit 35 - 45 1 65 1,2 4 596 996 15,1 Ferrit/Bainit 30 - 40 7 50 2 5 612 1021 13,8 Ferrit/Bainit 45 - 55 2 70 0,8 6 635 1036 16,8 Bainit/Ferrit 55 - 65 1,5 70 0,8 7 675 1079 13,7 Bainit 60 - 70 1 50 2 8 580 964 15,2 Ferrit/Bainit 20 - 30 2 65 1,2 9 613 1030 15,6 Bainit/Ferrit 45 - 55 3 70 0,8 10 665 1042 14,5 Bainit/Ferrit 60 - 70 1 70 0,8 11 597 977 16,7 Ferrit/Bainit 25 - 35 3 50 2 12 645 1063 14,7 Bainit 55 - 65 1 50 2 13 624 1003 16,3 Ferrit/Bainit 30 - 40 5 65 1,2 14 627 998 14,2 Ferrit/Bainit 30 - 40 2 65 1,2 15 589 985 15 Ferrit/Bainit 30 - 40 3 50 2 16 * 616 1026 14,5 Bainit/Ferrit 45 - 55 1 70 0,8 * Außer dem beanspruchten Gegenstand Tabelle 3 Schmelze Ap0.2 Rm A80 Gefüge Matrix Martensit [MPa] [MPa] [%] [%] 1 936 1013 9,3 Bainit 30 - 35 2 810 1011 10,1 Bainit 30 3 860 995 11,2 Bainit 25 - 30 4 796 1037 10,9 Bainit 45 5 818 999 9,8 Bainit 30 6 838 996 10,2 Bainit 30 7 803 992 9,8 Bainit 25 - 30 8 846 1013 10,9 Bainit 30 - 40 9 923 1050 10,3 Bainit 35 - 40 10 890 1034 10,1 Bainit 35 - 40 11 820 1011 10,4 Bainit / bainitischer Ferrit 30 12 910 1025 9,8 Bainit / bainitischer Ferrit 30 - 35 13 879 1015 11,1 Bainit / bainitischer Ferrit 25 - 30 14 865 1026 9,7 Bainit 35 15 804 997 10,8 Bainit 20 16 * 906 1042 10,1 Bainit 40 - 45 * Außer dem beanspruchten Gegenstand Tabelle 4 Schmelze Rp0.2 Rm A80 Gefüge Matrix Martensit [MPa] [MPa] [%] [%] 1 802 984 9,5 Bainit, Anteile globularer Ferrit 20 2 810 1011 10,1 Bainit/banitischer Ferrit, Anteile globularer Ferrit 25-30 3 752 988 11,2 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20-25 4 838 978 11,3 Bainit, Anteile globularer Ferrit 2.0 5 810 1009 11,2 Bainit, Anteile globularer Ferrit 20-25 6 760 967 11,6 Bainit, Anteile globularer Ferrit 20 7 807 1007 10,1 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20 8 814 983 9,1 Bainit, Anteile globularer Ferrit 20-25 9 876 1037 11 Bainit, Anteile globularer Ferrit 30 10 864 1023 9,8 Bainit/banitischer Ferrit, Anteile globularer Ferrit 30-35 11 789 998 10,6 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20 12 832 1003 10,5 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20-25 13 851 1006 11,9 Bainit, Anteile globularer Ferrit 20-25 14 824 997 9,8 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20 15 798 986 11 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20-25 16 * 854 1011 10,2 Bainit/banitischer Ferrit, Anteile globularer Ferrit 25-30 * Auβer dem beanspruchten Gegenstand Tabelle 5 Schmelze Rp0.2 Rm A80 Gefüge Matrix Martensit [MPa] [MPa] [%] [%] 1 787 1000 11,1 Bainit/banitischer Ferrit, Anteile globularer Ferrit 25 2 821 1012 12,2 Bainit, Anteile globularer Ferrit 30 3 795 998 9,3 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20-25 4 787 1001 10,7 Bainit, Anteile globularer Ferrit 25 5 822 1013 11,2 Bainit/banitischer Ferrit, Anteile globularer Ferrit 30 6 792 998 9,6 Bainit, Anteile globularer Ferrit 20-25 7 862 1003 10,9 Bainit, Anteile globularer Ferrit 20-25 8 826 991 10,2 Bainit, Anteile globularer Ferrit 20-25 9 812 1003 12,4 Bainit/banitischer Ferrit, Anteile globularer Ferrit 30 10 898 1065 11 Bainit/banitischer Ferrit, Anteile globularer Ferrit 30-35 11 780 994 10,6 Bainit, Anteile globularer Ferrit 20-25 12 866 987 10,4 Bainit, Anteile globularer Ferrit 20-25 13 784 998 11,1 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20 14 802 1002 11 Bainit/banitischer Ferrit, Anteile globularer Ferrit 20-25 15 826 991 10,2 Bainit, Anteile globularer Ferrit 20-25 16 * 833 1008 11,4 Bainit, Anteile globularer Ferrit 20-25 * Außer dem beanspruchten Gegenstand Tabelle 6 Schmelze Rp0.2 Rm A80 Gefüge Matrix Martensit [MPa] [MPa] [%] [%] 1 833 1034 14,6 Bainit (bainit. Ferrit, 4 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 25 2 760 1004 17,3 Bainit (bainit. Ferrit, 4 % Restaustenit, Karbidausscheidungen) 20 3 821 1014 10,7 Bainit (bainit. Ferrit, 2 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 25 4 862 1016 10,4 Bainit (bainit. Ferrit, < 1 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 - 25 5 829 996 16,7 Bainit (bainit. Ferrit, 3 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 6 807 1014 15,9 Bainit (bainit. Ferrit, 4,5 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 7 742 990 18,2 Bainit (bainit. Ferrit, 2 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 8 867 1046 10,8 Bainit (bainit. Ferrit, 1 % Restaustenit, Karbidausscheidungen) 20 - 25 9 780 1003 16,3 Bainit (bainit. Ferrit, 3,5 % Restaustenit, Karbidausscheidungen) 20 10 887 1007 9,5 Bainit (bainit. Ferrit < 1 % Restaustenit, Karbidausscheidungen) 20 11 787 1024 15,8 Bainit (bainit. Ferrit, 4 % Restaustenit, Karbidausscheidungen) 20 12 822 985 16,3 Bainit (bainit. Ferrit, 2 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 13 782 1001 10 Bainit (bainit. Ferrit < 1 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 25 14 824 1029 13,9 Bainit (bainit. Ferrit, 3,5 % Restaustenit, Karbidausscheidungen) 20 15 848 1027 11,7 Bainit (bainit. Ferrit, 2 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 16 * 779 1004 15,3 Bainit (bainitischer Ferrit, 4 % Restaustenit, Karbidausscheidungen), Anteile globularer Ferrit 20 * Außer dem beanspruchten Gegenstand In four further series of experiments, the hot strips produced from melts 1 to 16 in the manner described above were rewound at a reel temperature lower than 100 ° C, at 500 ° C, at 600 ° C and at 650 ° C. The properties determined for these hot strips are given in Tables 3 (reel temperature 20 ° C), 4 (reel temperature = 500 ° C), 5 (reel temperature = 580 ° C) and 6 (reel temperature = 650 ° C). The hot strips thus obtained were not intended for cold rolling, but have been supplied as hot strips - possibly after application of a metallic protective coating - the further processing to components. Table 1 melt C Si Mn al Not a word Ti Cr B P S N 1 0.087 0.18 2.22 0,007 0,100 0,050 0.60 0.001 0,007 0,004 0.0045 2 0,069 0.28 2.62 0.04 0.092 0,080 0.58 0.0015 0,008 0.0015 0.0031 3 0,095 0.23 2.27 0.031 0.10 0,075 0.62 0.0012 0,013 0,002 0.0051 4 0,089 0.22 2.31 0.034 0,050 0.081 0.64 0.0017 0,012 0.0021 0.0036 5 0.091 0.31 2.52 0.034 0,150 0,052 0.42 0.0011 0.009 0,003 0.0046 6 0,060 0.26 2.15 0,041 0,250 0,051 0.25 0.001 0,012 0.0019 0.0052 7 0,102 0.15 2.26 0,038 0,050 0,090 0.80 0.0018 0.009 0.0021 0.0049 8th 0,065 0.60 2.64 0.032 0,095 0,025 0.45 0.0012 0,014 0.0017 0.0039 9 0.063 0.16 2.10 0,035 0.240 0.063 0.71 0.0011 0,008 0.0021 0.0046 10 0.092 0.35 2.12 0.032 0.098 0.077 0.46 0.0017 0,013 0,003 0.0033 11 0,100 0.21 2.34 0,042 0.130 0,065 0.47 0.0018 0,014 0.0017 0.0032 12 0.072 0.50 2.65 0.031 0,160 0,089 0.32 0.0014 0.009 0.0021 0.005 13 0,076 0.34 2.39 0.037 0,200 0.057 0.54 0.0015 0,012 0.0015 0.0047 14 0.084 0.23 2.52 0.037 0,060 0.031 0.63 0.001 0,008 0.0033 0.0032 15 0.092 0.15 2.27 0.033 0.210 0,035 0.75 0.0013 0,014 0.0018 0.0041 16 * 0.083 0.05 2.20 0.032 0,170 0,070 0.80 0.0016 0,013 0.0018 0.0032 Data in wt .-%, balance iron and unavoidable impurities
* Except the claimed item melt R p0.2 R m A 80 structure Cold rolling reduction thickness matrix martensite austenite [MPa] [%] [%] [%] [%] [Mm] 1 601 980 14.8 Ferrite / bainite 35 - 40 3 50 2 2 659 1038 15.9 Bainite / ferrite 40 - 50 2 50 2 3 621 1012 14.6 Bainite / ferrite 35 - 45 1 65 1.2 4 596 996 15.1 Ferrite / bainite 30 - 40 7 50 2 5 612 1021 13.8 Ferrite / bainite 45 - 55 2 70 0.8 6 635 1036 16.8 Bainite / ferrite 55 - 65 1.5 70 0.8 7 675 1079 13.7 bainit 60 - 70 1 50 2 8th 580 964 15.2 Ferrite / bainite 20 - 30 2 65 1.2 9 613 1030 15.6 Bainite / ferrite 45 - 55 3 70 0.8 10 665 1042 14.5 Bainite / ferrite 60 - 70 1 70 0.8 11 597 977 16.7 Ferrite / bainite 25 - 35 3 50 2 12 645 1063 14.7 bainit 55 - 65 1 50 2 13 624 1003 16.3 Ferrite / bainite 30 - 40 5 65 1.2 14 627 998 14.2 Ferrite / bainite 30 - 40 2 65 1.2 15 589 985 15 Ferrite / bainite 30 - 40 3 50 2 16 * 616 1026 14.5 Bainite / ferrite 45 - 55 1 70 0.8 * Except the claimed item melt A p0.2 R m A 80 structure matrix martensite [MPa] [MPa] [%] [%] 1 936 1013 9.3 bainit 30 - 35 2 810 1011 10.1 bainit 30 3 860 995 11.2 bainit 25 - 30 4 796 1037 10.9 bainit 45 5 818 999 9.8 bainit 30 6 838 996 10.2 bainit 30 7 803 992 9.8 bainit 25 - 30 8th 846 1013 10.9 bainit 30 - 40 9 923 1050 10.3 bainit 35 - 40 10 890 1034 10.1 bainit 35 - 40 11 820 1011 10.4 Bainite / bainitic ferrite 30 12 910 1025 9.8 Bainite / bainitic ferrite 30 - 35 13 879 1015 11.1 Bainite / bainitic ferrite 25 - 30 14 865 1026 9.7 bainit 35 15 804 997 10.8 bainit 20 16 * 906 1042 10.1 bainit 40 - 45 * Except the claimed item melt R p0.2 R m A 80 structure matrix martensite [MPa] [MPa] [%] [%] 1 802 984 9.5 Bainite, proportions of globular ferrite 20 2 810 1011 10.1 Bainite / Banitic ferrite, proportions of globular ferrite 25-30 3 752 988 11.2 Bainite / Banitic ferrite, proportions of globular ferrite 20-25 4 838 978 11.3 Bainite, proportions of globular ferrite 2.0 5 810 1009 11.2 Bainite, proportions of globular ferrite 20-25 6 760 967 11.6 Bainite, proportions of globular ferrite 20 7 807 1007 10.1 Bainite / Banitic ferrite, proportions of globular ferrite 20 8th 814 983 9.1 Bainite, proportions of globular ferrite 20-25 9 876 1037 11 Bainite, proportions of globular ferrite 30 10 864 1023 9.8 Bainite / Banitic ferrite, proportions of globular ferrite 30-35 11 789 998 10.6 Bainite / Banitic ferrite, proportions of globular ferrite 20 12 832 1003 10.5 Bainite / Banitic ferrite, proportions of globular ferrite 20-25 13 851 1006 11.9 Bainite, proportions of globular ferrite 20-25 14 824 997 9.8 Bainite / Banitic ferrite, proportions of globular ferrite 20 15 798 986 11 Bainite / Banitic ferrite, proportions of globular ferrite 20-25 16 * 854 1011 10.2 Bainite / Banitic ferrite, proportions of globular ferrite 25-30 * Except the claimed object melt R p0.2 R m A 80 structure matrix martensite [MPa] [MPa] [%] [%] 1 787 1000 11.1 Bainite / Banitic ferrite, proportions of globular ferrite 25 2 821 1012 12.2 Bainite, proportions of globular ferrite 30 3 795 998 9.3 Bainite / Banitic ferrite, proportions of globular ferrite 20-25 4 787 1001 10.7 Bainite, proportions of globular ferrite 25 5 822 1013 11.2 Bainite / Banitic ferrite, proportions of globular ferrite 30 6 792 998 9.6 Bainite, proportions of globular ferrite 20-25 7 862 1003 10.9 Bainite, proportions of globular ferrite 20-25 8th 826 991 10.2 Bainite, proportions of globular ferrite 20-25 9 812. 1003 12.4 Bainite / Banitic ferrite, proportions of globular ferrite 30 10 898 1065 11 Bainite / Banitic ferrite, proportions of globular ferrite 30-35 11 780 994 10.6 Bainite, proportions of globular ferrite 20-25 12 866 987 10.4 Bainite, proportions of globular ferrite 20-25 13 784 998 11.1 Bainite / Banitic ferrite, proportions of globular ferrite 20 14 802 1002 11 Bainite / Banitic ferrite, proportions of globular ferrite 20-25 15 826 991 10.2 Bainite, proportions of globular ferrite 20-25 16 * 833 1008 11.4 Bainite, proportions of globular ferrite 20-25 * Except the claimed item melt Rp 0.2 R m A 80 structure matrix martensite [MPa] [MPa] [%] [%] 1 833 1034 14.6 Bainite (bainite ferrite, 4% retained austenite, carbide precipitates), levels of globular ferrite 25 2 760 1004 17.3 Bainite (bainite ferrite, 4% retained austenite, carbide precipitates) 20 3 821 1014 10.7 Bainite (bainite ferrite, 2% retained austenite, carbide precipitates), globular ferrite levels 25 4 862 1016 10.4 Bainite (bainite ferrite, <1% retained austenite, carbide precipitates), globular ferrite levels 20 - 25 5 829 996 16.7 Bainite (bainite ferrite, 3% retained austenite, carbide precipitates), globular ferrite levels 20 6 807 1014 15.9 Bainite (bainite ferrite, 4.5% retained austenite, carbide precipitates), globular ferrite levels 20 7 742 990 18.2 Bainite (bainite ferrite, 2% retained austenite, carbide precipitates), globular ferrite levels 20 8th 867 1046 10.8 Bainite (bainite ferrite, 1% retained austenite, carbide precipitates) 20 - 25 9 780 1003 16.3 Bainite (bainite ferrite, 3.5% retained austenite, carbide precipitates) 20 10 887 1007 9.5 Bainite (bainite ferrite <1% retained austenite, carbide precipitates) 20 11 787 1024 15.8 Bainite (bainite ferrite, 4% retained austenite, carbide precipitates) 20 12 822 985 16.3 Bainite (bainite ferrite, 2% retained austenite, carbide precipitates), globular ferrite levels 20 13 782 1001 10 Bainite (bainite ferrite <1% retained austenite, carbide precipitates), globular ferrite content 25 14 824 1029 13.9 Bainite (bainite ferrite, 3.5% retained austenite, carbide precipitates) 20 15 848 1027 11.7 Bainite (bainite ferrite, 2% retained austenite, carbide precipitates), globular ferrite levels 20 16 * 779 1004 15.3 Bainite (bainitic ferrite, 4% retained austenite, carbide precipitates), globular ferrite content 20 * Except the claimed item

Claims (31)

  1. Dual-phase steel, the structure of which consists to 20 - 70 % of martensite, up to 8 % of retained austenite and for the remainder of ferrite and/or bainite and which has a tensile strength of at least 950 MPa, with the following composition (in % by weight): C: 0.050 - 0.105 %, Si: 0.10 - 0.60 %, Mn: 2.10 - 2.80 %, Cr: 0.20 - 0.80 %, Ti: 0.02 - 0.10 %, B: < 0.0020 %, Mo: < 0.25 %, Al: < 0.10 %, Cu: up to 0.20 %, Ni: up to 0.10 %, Ca: up to 0.005 %, P: up to 0.2 %, S: up to 0.01 %, N: up to 0.012 %
    the remainder being iron and unavoidable impurities.
  2. Dual-phase steel according to claim 1, characterised in that the yield strength thereof is at least 580 MPa.
  3. Dual-phase steel according to either one of the preceding claims, characterised in that the elongation A80 thereof is at least 10 %.
  4. Dual-phase steel according to any one of the preceding claims, characterised in that the P content thereof is < 0.1 % by weight, in particular < 0.020 % by weight.
  5. Dual-phase steel according to any one of the preceding claims, characterised in that the C content thereof is from 0.06 to 0.09 % by weight.
  6. Dual-phase steel according to any one of the preceding claims, characterised in that the Si content thereof is from 0.20 to 0.40 % by weight.
  7. Dual-phase steel according to any one of the preceding claims, characterised in that the Mn content thereof is from 2.20 to 2.70 % by weight.
  8. Dual-phase steel according to any one of the preceding claims, characterised in that the Cr content thereof is from 0.40 to 0.70 % by weight.
  9. Dual-phase steel according to any one of the preceding claims, characterised in that the Ti content thereof is from 0.060 to 0.090 % by weight.
  10. Dual-phase steel according to any one of the preceding claims, characterised in that in the presence of N, the Ti content of said dual-phase steel is more than 5.1 times the respective N content.
  11. Dual-phase steel according to any one of the preceding claims, characterised in that the B content thereof is from 0.0005 to 0.002 % by weight.
  12. Dual-phase steel according to claim 11, characterised in that the B content thereof is from 0.0007 to 0.0015 % by weight.
  13. Dual-phase steel according to any one of the preceding claims, characterised in that the Mo content thereof is from 0.05 to 0.20 % by weight.
  14. Dual-phase steel according to claim 13, characterised in that the Cr content thereof is < 0.3 % by weight.
  15. Dual-phase steel according to either claim 13 or claim 14, characterised in that the Mo content thereof is from 0.065 to 0.150 % by weight.
  16. Dual-phase steel according to any one of the preceding claims, characterised in that the Al content thereof is from 0.01 to 0.06 % by weight.
  17. Dual-phase steel according to any one of the preceding claims, characterised in that the Cu content thereof is from 0.07 to 0.13 % by weight.
  18. Dual-phase steel according to any one of the preceding claims, characterised in that the S content thereof is < 0.003 % by weight.
  19. Dual-phase steel according to any one of the preceding claims, characterised in that the N content thereof is < 0.007 % by weight.
  20. Dual-phase steel according to any one of the preceding claims, characterised in that the retained austenite content thereof is less than 7 %.
  21. Flat product consisting of a dual-phase steel obtained according to any one of claims 1 to 20.
  22. Flat product according to claim 21, characterised in that it is a hot strip which has only been hot-rolled.
  23. Flat product according to claim 21, characterised in that it is a cold strip obtained by cold rolling.
  24. Flat product according to any one of claims 21 to 23, characterised in that it is provided with a protective metallic coating.
  25. Flat product according to claim 24, characterised in that the protective metallic coating is produced by hot-dip galvanisation.
  26. Flat product according to claim 24, characterised in that the protective metallic coating is produced by galvannealing.
  27. Process for the production of a hot strip having a tensile strength of at least 950 MPa and a dual-phase structure which consists to 20 - 70 % of martensite, up to 8 % of retained austenite and for the remainder of ferrite and/or bainite, comprising the following steps:
    - melting a dual-phase steel composed according to any one of claims 1 to 20,
    - casting the melt into a pre-product, such as slab or thin slab,
    - reheating to or keeping the pre-product at a starting hot rolling temperature of 1100 - 1300 °C,
    - hot rolling the pre-product at a final hot rolling temperature of 800 - 950 °C into a hot strip,
    - reeling the hot strip at a reeling temperature of up to 650 °C, in particular 500 - 650 °C.
  28. Process according to claim 27, characterised in that a cold strip is produced from the warm strip obtained after reeling, by conducting the following additional working steps:
    - cold-rolling the hot strip into a cold strip,
    - annealing the cold strip at an annealing temperature of 700 - 900 °C, and
    - cooling the annealed cold strip in a controlled manner.
  29. Process according to either claim 27 or claim 28, characterised in that the reeling temperature is higher than 500 °C up to 580 °C.
  30. Process according to any one of claims 27 to 29, characterised in that the hot strip is cold-rolled into a cold strip with a degree of cold-rolling of from 40 to 70 %.
  31. Process according to any one of claims 27 to 30, characterised in that the controlled cooling is carried out within a temperature range of from 550 to 650 °C at a cooling rate of at least 10 K/s.
EP07114399A 2007-08-15 2007-08-15 Dual-phase steel, flat product made of such dual-phase steel and method for manufacturing a flat product Active EP2031081B1 (en)

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PL07114399T PL2031081T3 (en) 2007-08-15 2007-08-15 Dual-phase steel, flat product made of such dual-phase steel and method for manufacturing a flat product
AT07114399T ATE516380T1 (en) 2007-08-15 2007-08-15 DUAL PHASE STEEL, FLAT PRODUCT FROM SUCH A DUAL PHASE STEEL AND METHOD FOR PRODUCING A FLAT PRODUCT
EP07114399A EP2031081B1 (en) 2007-08-15 2007-08-15 Dual-phase steel, flat product made of such dual-phase steel and method for manufacturing a flat product
ES07114399T ES2367713T3 (en) 2007-08-15 2007-08-15 STEEL OF DUAL PHASE, FLAT PRODUCT OF A STEEL OF DUAL PHASE SIZE AND PROCEDURE FOR THE MANUFACTURE OF A FLAT PRODUCT.
US12/673,279 US20110220252A1 (en) 2007-08-15 2008-08-07 Dual-phase steel, flat product made of such a dual-phase steel and process for the production of a flat product
CN2008801034281A CN101802237B (en) 2007-08-15 2008-08-07 Dual-phase steel, flat product made of such dual-phase steel and method for producing a flat product
JP2010520537A JP5520221B2 (en) 2007-08-15 2008-08-07 Flat product made of two-phase steel and two-phase steel and method for producing flat product
PCT/EP2008/060382 WO2009021898A1 (en) 2007-08-15 2008-08-07 Dual-phase steel, flat product made of such dual-phase steel and method for producing a flat product

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2666392C2 (en) * 2013-07-30 2018-09-07 Зальцгиттер Флахшталь Гмбх Micro-alloyed high-strength multi-phase steel containing silicon with minimum tensile strength of 750 mpa improved properties and method for producing a strip from said steel
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Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102851611B (en) * 2011-06-29 2014-03-05 宝山钢铁股份有限公司 Ultrahigh toughness steel plate for deep-water pressure resistant shell and manufacture method thereof
US9115416B2 (en) * 2011-12-19 2015-08-25 Kobe Steel, Ltd. High-yield-ratio and high-strength steel sheet excellent in workability
DE102011056847B4 (en) 2011-12-22 2014-04-10 Thyssenkrupp Rasselstein Gmbh Steel sheet for use as a packaging steel and process for the production of a packaging steel
DE102012002079B4 (en) 2012-01-30 2015-05-13 Salzgitter Flachstahl Gmbh Process for producing a cold or hot rolled steel strip from a high strength multiphase steel
JP6228741B2 (en) * 2012-03-27 2017-11-08 株式会社神戸製鋼所 High-strength hot-dip galvanized steel sheet, high-strength alloyed hot-dip galvanized steel sheet, which has a small difference in strength between the central part and the end part in the sheet width direction and has excellent bending workability, and methods for producing these
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DE102014017274A1 (en) 2014-11-18 2016-05-19 Salzgitter Flachstahl Gmbh Highest strength air hardening multiphase steel with excellent processing properties and method of making a strip from this steel
AU2016206736B2 (en) * 2015-01-14 2019-02-14 Ak Steel Properties, Inc. Dual phase steel with improved properties
DE102015111177A1 (en) 2015-07-10 2017-01-12 Salzgitter Flachstahl Gmbh High strength multi-phase steel and method of making a cold rolled steel strip therefrom
DE102015112889A1 (en) * 2015-08-05 2017-02-09 Salzgitter Flachstahl Gmbh High-strength manganese-containing steel, use of the steel for flexibly rolled flat steel products and production methods together with flat steel product for this purpose
KR101736620B1 (en) * 2015-12-15 2017-05-17 주식회사 포스코 Ultra-high strength steel sheet having excellent phosphatability and hole expansibility, and method for manufacturing the same
DE102017204099A1 (en) * 2016-03-15 2017-09-21 Ksb Aktiengesellschaft Method for producing components from a duplex steel and components produced by the method
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CN106756512B (en) * 2017-01-12 2018-12-18 唐山钢铁集团有限责任公司 The hot rolling complex phase high strength steel plate and its production method of one steel multistage
CN109207867A (en) * 2017-06-29 2019-01-15 宝山钢铁股份有限公司 A kind of cold rolled annealed dual phase steel, steel plate and its manufacturing method
DE102017123236A1 (en) 2017-10-06 2019-04-11 Salzgitter Flachstahl Gmbh Highest strength multi-phase steel and process for producing a steel strip from this multi-phase steel
DE102017218434A1 (en) 2017-10-16 2019-04-18 Thyssenkrupp Ag Enameling of high-strength steels
CN109097676A (en) * 2018-08-06 2018-12-28 首钢集团有限公司 A kind of alloyed zinc hot dip galvanized dual phase steel and preparation method thereof
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Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1146784A (en) * 1995-01-26 1997-04-02 新日本制铁株式会社 Weldable high-tensile steel excellent in low-temp. toughness
JP3254106B2 (en) * 1995-05-19 2002-02-04 株式会社神戸製鋼所 Ultra-high-strength steel sheet excellent in hydrogen embrittlement resistance and method for producing the same
DE19710125A1 (en) * 1997-03-13 1998-09-17 Krupp Ag Hoesch Krupp Process for the production of a steel strip with high strength and good formability
JP2000282175A (en) * 1999-04-02 2000-10-10 Kawasaki Steel Corp Superhigh strength hot-rolled steel sheet excellent in workability, and its production
DE19936151A1 (en) * 1999-07-31 2001-02-08 Thyssenkrupp Stahl Ag High-strength steel strip or sheet and process for its manufacture
JP4085583B2 (en) * 2001-02-27 2008-05-14 Ｊｆｅスチール株式会社 High-strength cold-rolled galvanized steel sheet and method for producing the same
EP1288322A1 (en) * 2001-08-29 2003-03-05 Sidmar N.V. An ultra high strength steel composition, the process of production of an ultra high strength steel product and the product obtained
FR2833617B1 (en) * 2001-12-14 2004-08-20 Usinor METHOD FOR MANUFACTURING VERY HIGH STRENGTH COLD ROLLED SHEET OF MICRO-ALLOY DUAL STEEL
FR2855184B1 (en) * 2003-05-19 2006-05-19 Usinor COLD LAMINATED, ALUMINATED, HIGH STRENGTH, DUAL PHASE STEEL FOR TELEVISION ANTI-IMPLOSION BELT, AND METHOD FOR MANUFACTURING THE SAME
JP3934604B2 (en) * 2003-12-25 2007-06-20 株式会社神戸製鋼所 High strength cold-rolled steel sheet with excellent coating adhesion
WO2005095664A1 (en) * 2004-03-31 2005-10-13 Jfe Steel Corporation High-rigidity high-strength thin steel sheet and method for producing same
JP4445365B2 (en) * 2004-10-06 2010-04-07 新日本製鐵株式会社 Manufacturing method of high-strength thin steel sheet with excellent elongation and hole expandability

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2666392C2 (en) * 2013-07-30 2018-09-07 Зальцгиттер Флахшталь Гмбх Micro-alloyed high-strength multi-phase steel containing silicon with minimum tensile strength of 750 mpa improved properties and method for producing a strip from said steel
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JP5520221B2 (en) 2014-06-11
PL2031081T3 (en) 2011-11-30
ATE516380T1 (en) 2011-07-15
CN101802237B (en) 2013-09-04
JP2010535947A (en) 2010-11-25
US20110220252A1 (en) 2011-09-15
ES2367713T3 (en) 2011-11-07
EP2031081A1 (en) 2009-03-04
CN101802237A (en) 2010-08-11
WO2009021898A1 (en) 2009-02-19

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