WO2007141152A1 - Manganese boron steel, flat products produced from such steel, and production method - Google Patents

Manganese boron steel, flat products produced from such steel, and production method Download PDF

Info

Publication number
WO2007141152A1
WO2007141152A1 PCT/EP2007/055130 EP2007055130W WO2007141152A1 WO 2007141152 A1 WO2007141152 A1 WO 2007141152A1 EP 2007055130 W EP2007055130 W EP 2007055130W WO 2007141152 A1 WO2007141152 A1 WO 2007141152A1
Authority
WO
WIPO (PCT)
Prior art keywords
hot
steel
manganese
strip
cold
Prior art date
Application number
PCT/EP2007/055130
Other languages
German (de)
French (fr)
Inventor
Jian Bian
Original Assignee
Thyssenkrupp Steel Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thyssenkrupp Steel Ag filed Critical Thyssenkrupp Steel Ag
Publication of WO2007141152A1 publication Critical patent/WO2007141152A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0405—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/10—Alloys based on aluminium with zinc as the next major constituent
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/02—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
    • C23C28/021—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material including at least one metal alloy layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
    • C23C28/023—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only
    • C23C28/025—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only with at least one zinc-based layer

Definitions

  • the invention relates to a manganese-boron steel, a flat product produced from such a steel and a process for its production.
  • MnB steels of this type are used in particular in the field of automotive engineering for the production of components, which should have a high strength in addition to a low weight.
  • 22MnB5 steel A MnB steel proven in practice for the purposes summarized above is known as "22MnB5" and has been given the material number 1.5528 in the steel key, 2004 edition.
  • 22MnB5 steel available on the market contains, in addition to iron and unavoidable impurities (in wt%), 0.220-0.250% C, 1.2-1.4% Mn, 0.2-0.3% Si, up to 0 , 02% P, up to 0.005% S, 0.020-0.050% Al, 0.020-0.050% Ti, 0.11-0.2% Cr, 0.002-0.0035% B and in each case up to 0.1% Mo, Cu and Ni (Material Data Sheet 11-112 of Salzgitter Flachstahl GmbH, November 2005 edition).
  • EP 0 971 044 B1 specifies an alloying specification according to which a MnB steel, in addition to iron and unavoidable impurities (in% by weight), has a carbon content of more than 0, 20%, but less than 0.5%, a manganese content of more than 0.5%, but less than 3%, a silicon content of more than 0.1%, but less than 0.5%, a chromium content of more than 0.01% but less than 1%, a titanium content of less than 0.2%, an aluminum content of less than 0.1%, a phosphorus content of less than 0.1%, a sulfur content of less than 0.05% and a boron content of more than 0.0005%, but less than 0.08%.
  • an aluminum coating provided with an aluminum coating in EP 0 971 044 B1 has (in% by weight) 0.21% C, 1.14% Mn, 0.020% P, 0.0038% S, 0.25% Si, 0.04% Al, 0.009% Cu, 0.020% Ni, 0.18% Cr, 0.0040% N, 0.032% Ti, 0.003% B and 0.0050% Ca. After a heat treatment, the strength of this steel sheet should be more than 1500 MPa.
  • JP 2004-211197 a steel sheet for structural components of automobile bodies is known, which in addition to iron and unavoidable impurities (in wt .-%) 0.20 - 0.35% C, 0.01 - 1.0% Si, 0.3 - 2.0% Mn, 0.01 - 0.10% Al, more than 1-5% Ni, 0.005 - 0.1% Ti, 0.0005 - 0.005% B, 0.001 - 0.01% N, up to 0.02% P, up to 0.01% S, up to 0.01% O.
  • this alloy for the Ti and N contents the condition "Ti / 47.88
  • the steel sheet in question should have a particularly good hardenability after hot deformation combined with particularly good behavior in the event of a sudden impact.
  • the residual fracture strain of the known steels is typically only 5-6%.
  • steels are needed, in addition to a high strength and an improved elongation behavior of the manufactured from such a steel component after hot pressing.
  • the invention therefore an object of the invention to provide a steel which is suitable for the production of components with high strength and good elongation behavior after a hot press forming.
  • a flat steel product should be specified, which has improved mechanical properties in view of the requirements imposed in practice on such flat steel products, such as steel strips or steel sheets.
  • a method for producing such a flat steel product should be specified.
  • this object has been achieved by a manganese-boron steel containing (in% by weight) 0.1-0.20% C, 0.05-0.30% Si, 0.8. 1.8% Mn, 0.5-1.8% Ni, up to 0.015% P, up to 0.003% S, 0.0002-0.0080% B, and the balance iron and unavoidable impurities.
  • the MnB steel of the present invention may optionally contain 0.01-0.1% Ti, 0.01-0.05% Al, 0.002-0.005% N each in combination or alone.
  • contents of Cr have been dispensed with in the alloy concept according to the invention.
  • MnB steel according to the invention contains levels of Ni in order to significantly increase the elongation at break and toughness of components produced from the steel according to the invention after a hardened state obtained by hot press forming.
  • the presence of Ni improves the hardenability of MnB steels according to the invention, so that the Mn contents could be reduced and the addition of critical Cr in terms of its influence on the residual ductility could be dispensed with.
  • the C content of steels according to the invention has also been modified in such a way that the martensite hardness produced in the course of hot pressing is reduced or the components obtained after hot pressing have a bainitic structure in favor of improved extensibility, by virtue of the toughness and elongation at break of components produced from steel according to the invention is also positively influenced.
  • the C content in the range from 0.15 to 0.20% by weight can be set within the scope of the invention. For a less solid, but a particularly good residual ductility and toughness even after the hot pressing and the resulting hardening steel have in contrast C contents of 0.10 to 0.15 wt .-% proved to be useful.
  • the residual elongation and the hardenability of the steel according to the invention can be adjusted.
  • lower Ni contents lying in the range of 0.5-1.8% by weight, in particular in the range of 0.8-1.5% by weight lead to higher hardenability and at the same time to improved toughness, whereby together an improved residual elongation is achieved.
  • a steel according to the invention with lower strength but with further improved residual elongation after hardening achieved during hot deformation has (in% by weight) 0.10-0.15% C, 0.05-0.30% Si, 1, 0 - 1.8% Mn, 0.8 - 1.8% Ni, max. 0.015% P, max. 0.003% S, 0.0002 - 0.0080% B and the remainder iron and unavoidable impurities.
  • the hardening effect of boron occurs in a steel according to the invention, in particular when the B content is at least 0.0008% by weight.
  • the abovementioned object has accordingly been achieved according to the invention in that such a flat steel product, such as steel strip or sheet, has been produced from a manganese-boron steel composed according to the invention.
  • the flat steel product according to the invention may be a hot or cold rolled steel strip or sheet.
  • composite steel strips or steel sheets according to the invention are outstandingly suitable for surface refinement by application of a metallic coating. This can be applied for example by Feueralum ist or hot dip galvanizing and by a combination of these methods.
  • the corrosion protection respectively obtained by the metallic coating can additionally be improved by additionally providing the flat steel product according to the invention with an organic or inorganic coating.
  • tensile strengths R m of at least 1000 MPa after hot pressing can be guaranteed.
  • the elongation at break values A 80 of flat steel products according to the invention after hot pressing regularly exceed 10%.
  • the resulting hot strip can be descaled for further processing in a conventional manner, for example by pickling. If the resulting flat steel product is to be fed directly as a hot strip of the forming to a component, can now be applied as corrosion protection, a metallic coating in the manner already described above. Alternatively, the hot strip may be cold rolled after the pickling, if necessary, to cold strip. The degrees of cold rolling achieved during cold rolling, preferably without intervening intermediate annealing, should be at least 40% in order to ensure complete recrystallization.
  • Hot stripers were then hot rolled from the resulting Dunnbrammen.
  • the hot rolling end temperature was 850 ° C.
  • the resulting hot strips were rewound at a coiler temperature which was 560 ° C.
  • cold rolling degree reduction in thickness / thickness of the cold rolled hot strip achieved by the cold rolling
  • samples separated from the cold-rolled strips obtained were coated with a metallic coating by means of fire aluminizing.
  • the metallic coating consisted of 89-92% by weight of Al, balance Si.
  • a second sample was fire-aluminized with a coating containing 55% by weight of Al, 43.4% by weight of Zn and 1.6% by weight of Si.
  • a martensitic, a bainitic or a mixed martensitic-bainitic structure was present in the components obtained.
  • the hardness profiles of the steels Sl, S2 compared to the hardness curve of the conventionally assembled steel V are compared with those calculated according to the Jominiy test.
  • the respective hardness H is plotted over the respective distance A to the quenched surface.

Abstract

The invention relates to manganese-boron steel suitable for producing high-strength components with good ductile properties, even after hot pressing. For this purpose, the MnB steel according to the invention contains the following (in % by weight): C: 0,1 - 0,20%; Si: 0,05 - 0,30%; Mn: 0,8 - 1,8%; Ni 0,5 - 1,8%; P: £ 0,015%; S: £ 0,003%; B: 0,0002 - 0,0080%, as well as optionally one or several of the elements Ti, Al, and N, as follows: Ti: 0,01 - 0,1%; Al: 0,01 - 0,05%; N: 0,002 - 0,005%, with the remainder being iron and unavoidable impurities. In addition, the invention relates to flat steel products with improved mechanical properties, manufactured from steel according to the invention, as well as a method for the production of such flat steel products.

Description

MANGAN-BOR-STAHL, AUS EINEM SOLCHEN STAHL HERGESTELLTES FLACHPRODUKT UND VERFAHREN ZU DESSEN HERSTELLUNG MANGAN-BOR-STEEL, FLAT PRODUCT MANUFACTURED FROM SUCH STEEL AND METHOD FOR THE PRODUCTION THEREOF
Die Erfindung betrifft einen Mangan-Bor-Stahl, ein aus einem solchen Stahl hergestelltes Flachprodukt und ein Verfahren zu dessen Herstellung. MnB-Stähle dieser Art werden insbesondere im Bereich des Automobilbaus für die Herstellung von Bauteilen verwendet, die neben einem geringen Gewicht eine hohe Festigkeit besitzen sollen.The invention relates to a manganese-boron steel, a flat product produced from such a steel and a process for its production. MnB steels of this type are used in particular in the field of automotive engineering for the production of components, which should have a high strength in addition to a low weight.
Die an das Verformungsverhalten von modernen Automobilen im Crash-Fall gestellten hohen Sicherheitsanforderungen können heutzutage durch Verwendung von höherfesten Stählen zur Herstellung der bei einem Unfall für das Verformungsverhalten der Fahrzeug-Karosserie und der besonders kritischen Bauteile erfüllt werden. Problematisch ist dabei allerdings, dass hochfeste Stähle in der Regel eine unzureichende Umformbarkeit aufweisen und zum Rückfedern bei ihrer Kaltverformung zu dem jeweiligen Bauteil neigen.The high safety requirements placed on the deformation behavior of modern automobiles in the event of a crash today can be met by using higher-strength steels for producing the deformation behavior of the vehicle bodywork and the particularly critical components in the event of an accident. The problem is, however, that high-strength steels usually have insufficient formability and tend to spring back in their cold deformation to the respective component.
Dieses Problem wird in der Praxis dadurch bewältigt, dass aus höherfesten Stählen erzeugte Bleche im warmen Zustand in so genannten "Warmpressen" zum jeweiligen Bauteil verformt werden. Diese Vorgehensweise hat sich bewährt und erlaubt die Erzeugung auch von komplexer geformten Karosserie- und Fahrwerksteilen aus hochfesten Stählen. Als besonders gut geeignet für die Warmpressverformung haben sich Mangan-Bor-Stähle der hier in Rede stehenden Art erwiesen, die in der EN 10083-3 genormt sind. Diese Stähle besitzen eine gute Härtbarkeit, die beim Warmpressen eine sichere Prozessführung erlaubt und durch die es auf wirtschaftliche Weise möglich ist, im Zuge der Warmverformung eine Martensithärtung noch im Werkzeug ohne zusätzliche Kühlung zu bewirken.This problem is overcome in practice by the fact that sheets produced from higher-strength steels are deformed to the respective component in the warm state in so-called "hot pressing". This approach has proven itself and allows the production of complex molded body and chassis parts made of high-strength steels. Manganese-boron steels of the type in question, which are standardized in EN 10083-3, have proven particularly suitable for the hot-pressing deformation. These steels have a good hardenability, which allows safe process control during hot pressing and by which it is economically possible to effect a martensite hardening in the mold without additional cooling during the hot deformation.
Ein für die voranstehend zusammengefassten Zwecke in der Praxis bewährter MnB-Stahl ist unter der Bezeichnung "22MnB5" bekannt und hat im Stahlschlüssel, Ausgabe 2004, die Werkstoffnummer 1.5528 erhalten. Typischerweise enthält auf dem Markt erhältlicher 22MnB5-Stahl neben Eisen und unvermeidbaren Verunreinigungen (in Gew.-%) 0,220 - 0,250 % C, 1,2 - 1,4 % Mn, 0,2 - 0,3 % Si, bis zu 0,02 % P, bis zu 0,005 % S, 0,020 - 0,050 % Al, 0,020 - 0,050 % Ti, 0,11 - 0,2 % Cr, 0,002 - 0,0035 % B sowie jeweils bis zu 0,1 % Mo, Cu und Ni (Werkstoffdatenblatt 11-112 der Salzgitter Flachstahl GmbH, Ausgabe November 2005) .A MnB steel proven in practice for the purposes summarized above is known as "22MnB5" and has been given the material number 1.5528 in the steel key, 2004 edition. Typically, 22MnB5 steel available on the market contains, in addition to iron and unavoidable impurities (in wt%), 0.220-0.250% C, 1.2-1.4% Mn, 0.2-0.3% Si, up to 0 , 02% P, up to 0.005% S, 0.020-0.050% Al, 0.020-0.050% Ti, 0.11-0.2% Cr, 0.002-0.0035% B and in each case up to 0.1% Mo, Cu and Ni (Material Data Sheet 11-112 of Salzgitter Flachstahl GmbH, November 2005 edition).
Für entsprechend zusammengesetzte, warmgewalzte und mit einer Al-Beschichtung versehene Stahlbleche ist in der EP 0 971 044 Bl eine Legierungsvorschrift angegeben, gemäß der ein MnB-Stahl neben Eisen und unvermeidbaren Verunreinigungen (in Gew.-%) einen Kohlenstoffgehalt von mehr als 0,20 %, jedoch weniger als 0,5 %, einen Mangangehalt von mehr als 0,5 %, jedoch weniger als 3 %, einen Siliziumgehalt von mehr als 0,1 %, jedoch weniger als 0,5 %, einen Chromgehalt von mehr als 0,01 % jedoch weniger als 1 %, einen Titangehalt von weniger als 0,2 %, einen Aluminiumgehalt von weniger als 0,1 %, einen Phosphorgehalt von weniger als 0,1 %, einen Schwefelgehalt von weniger als 0,05 % und einen Borgehalt von mehr als 0,0005 %, jedoch weniger als 0,08 % aufweisen soll. Ein in der EP 0 971 044 Bl als Ausführungsbeispiel angegebenes, mit einer Al-Beschichtung versehenes Stahlblech weist dementsprechend (in Gew.-%) 0,21 % C, 1,14 % Mn, 0,020 % P, 0,0038 % S, 0,25 % Si, 0,04 % Al, 0,009 % Cu, 0,020 % Ni, 0,18 % Cr, 0,0040 % N, 0,032 % Ti, 0,003 % B und 0,0050 % Ca auf. Nach einer Wärmebehandlung soll die Festigkeit dieses Stahlblechs mehr als 1500 MPa betragen.For correspondingly assembled, hot-rolled steel sheets provided with an Al coating, EP 0 971 044 B1 specifies an alloying specification according to which a MnB steel, in addition to iron and unavoidable impurities (in% by weight), has a carbon content of more than 0, 20%, but less than 0.5%, a manganese content of more than 0.5%, but less than 3%, a silicon content of more than 0.1%, but less than 0.5%, a chromium content of more than 0.01% but less than 1%, a titanium content of less than 0.2%, an aluminum content of less than 0.1%, a phosphorus content of less than 0.1%, a sulfur content of less than 0.05% and a boron content of more than 0.0005%, but less than 0.08%. Accordingly, an aluminum coating provided with an aluminum coating in EP 0 971 044 B1 has (in% by weight) 0.21% C, 1.14% Mn, 0.020% P, 0.0038% S, 0.25% Si, 0.04% Al, 0.009% Cu, 0.020% Ni, 0.18% Cr, 0.0040% N, 0.032% Ti, 0.003% B and 0.0050% Ca. After a heat treatment, the strength of this steel sheet should be more than 1500 MPa.
Des Weiteren ist aus der JP 2004-211197 ein Stahlblech für Strukturbauteile von Automobilkarosserien bekannt, das neben Eisen und unvermeidbaren Verunreinigungen (in Gew.-%) 0,20 - 0,35 % C, 0,01 - 1,0 % Si, 0,3 - 2,0 % Mn, 0,01 - 0,10 % Al, mehr als 1 - 5 % Ni, 0,005 - 0,1 % Ti, 0,0005 - 0,005 % B, 0,001 - 0,01 % N, bis zu 0,02 % P, bis zu 0,01 % S, bis zu 0,01 % O aufweist. In dem bei dieser Legierung für die Ti- und N-Gehalte die Bedingung "Ti/47.88Furthermore, from JP 2004-211197 a steel sheet for structural components of automobile bodies is known, which in addition to iron and unavoidable impurities (in wt .-%) 0.20 - 0.35% C, 0.01 - 1.0% Si, 0.3 - 2.0% Mn, 0.01 - 0.10% Al, more than 1-5% Ni, 0.005 - 0.1% Ti, 0.0005 - 0.005% B, 0.001 - 0.01% N, up to 0.02% P, up to 0.01% S, up to 0.01% O. In the case of this alloy for the Ti and N contents, the condition "Ti / 47.88
- N/14.01 < 0,001", für die Al- und N-Gehalte die Bedingung- N / 14.01 <0.001 ", for the Al and N contents the condition
"0 < Al/26.98 - N/14.01 < 0,0015" sowie für die C-, Si-, Mn-, Ni-, Cr-, Cu-, S- und P-Gehalte die Bedingung "-28.8 x C2 + 38.0 x C + 1.7 x Si + 7.5 x Mn + 1.4 x Ni + 43.2 x Cr"0 <Al / 26.98 - N / 14.01 <0.0015" and for the C, Si, Mn, Ni, Cr, Cu, S and P contents the condition "-28.8 x C 2 + 38.0 x C + 1.7 x Si + 7.5 x Mn + 1.4 x Ni + 43.2 x Cr
+ 8.7 x Cu + 53.5 x S + 57.1 x P + 17.9 > 35" eingehalten werden, soll das betreffende Stahlblech eine besonders gute Härtbarkeit nach der Warmverformung bei gleichzeitig besonders gutem Verhalten bei einem schlagartigen Stoß besitzen .+ 8.7 x Cu + 53.5 x S + 57.1 x P + 17.9> 35 ", the steel sheet in question should have a particularly good hardenability after hot deformation combined with particularly good behavior in the event of a sudden impact.
Den voranstehend genannten, konventionellen MnB-Stählen gemeinsam ist, dass sie zwar jeweils hohe Festigkeiten und eine gute Härtbarkeit aufweisen. Ihre hohe Festigkeit nach dem Warmpressen ergibt sich dabei durch den im Martensitgitter gelösten Kohlenstoff, während ihre gute Härtbarkeit maßgeblich durch die Mn- und Cr- Gehalte und ergänzt durch B bestimmt wird.What is common to the above-mentioned conventional MnB steels is that they each have high strengths and good hardenability. Their high strength after hot pressing results from the dissolved carbon in martensite, while their good Hardening significantly by the Mn and Cr contents and supplemented by B is determined.
Die Restbruchdehnung der bekannten Stähle liegt allerdings typischerweise nur bei 5 - 6 %. Um den immer weiter steigenden Anforderungen an das Crash-Verhalten von Fahrzeugkarosserien gerecht zu werden, werden jedoch Stähle benötigt, die neben einer hohen Festigkeit auch ein verbessertes Dehnungsverhalten des aus einem solchen Stahl gefertigten Bauteils nach dem Warmpressen aufweisen.The residual fracture strain of the known steels, however, is typically only 5-6%. In order to meet the ever-increasing demands on the crash behavior of vehicle bodies, however, steels are needed, in addition to a high strength and an improved elongation behavior of the manufactured from such a steel component after hot pressing.
Ausgehend von dem voranstehend erläuterten Stand der Technik lag der Erfindung daher die Aufgabe zugrunde, einen Stahl anzugeben, der zur Herstellung von Bauteilen mit hoher Festigkeit und gutem Dehnungsverhalten auch nach einer Warmpressverformung geeignet ist. Darüber hinaus sollte ein Stahlflachprodukt angegeben werden, das im Hinblick auf die in der Praxis an aus solchen Stahlflachprodukten, wie Stahlbändern oder Stahlblechen, hergestellten Bauteilen gestellten Anforderungen verbesserte mechanische Eigenschaften aufweist. Schließlich sollte ein Verfahren zur Herstellung eines solchen Stahlflachproduktes angegeben werden.Starting from the above-described prior art, the invention therefore an object of the invention to provide a steel which is suitable for the production of components with high strength and good elongation behavior after a hot press forming. In addition, a flat steel product should be specified, which has improved mechanical properties in view of the requirements imposed in practice on such flat steel products, such as steel strips or steel sheets. Finally, a method for producing such a flat steel product should be specified.
In Bezug auf den Stahl ist diese Aufgabe durch einen Mangan-Bor-Stahl gelöst worden, der (in Gew.-%) 0,1 - 0,20 % C, 0,05 - 0,30 % Si, 0,8 - 1,8 % Mn, 0,5 - 1,8 % Ni, bis zu 0,015 % P, bis zu 0,003 % S, 0,0002 - 0,0080 % B und als Rest Eisen und unvermeidbare Verunreinigungen enthält. Zusätzlich kann der erfindungsgemäße MnB-Stahl wahlweise 0,01 - 0,1 % Ti, 0,01 - 0,05 % Al, 0,002 - 0,005 % N jeweils in Kombination oder alleine enthalten. Im Gegensatz zu den konventionellen MnB-Stählen, bei denen die mechanischen Eigenschaften maßgeblich durch die C-, Mn- und Cr-Gehalte bestimmt werden, ist bei dem erfindungsgemäßen Legierungskonzept auf Gehalte an Cr verzichtet worden. Stattdessen enthält erfindungsgemäßer MnB-Stahl Gehalte an Ni, um die Bruchdehnung und Zähigkeit von aus dem erfindungsgemäßen Stahl hergestellten Bauteilen nach einem Warmpressverformen erhaltenen gehärteten Zustand maßgeblich zu steigern. Gleichzeitig verbessert die Anwesenheit von Ni die Härtbarkeit erfindungsgemäßer MnB- Stähle, so dass die Mn-Gehalte reduziert und auf die Zugabe von hinsichtlich seines Einflusses auf die Restdehnbarkeit kritischem Cr verzichtet werden konnte.With respect to steel, this object has been achieved by a manganese-boron steel containing (in% by weight) 0.1-0.20% C, 0.05-0.30% Si, 0.8. 1.8% Mn, 0.5-1.8% Ni, up to 0.015% P, up to 0.003% S, 0.0002-0.0080% B, and the balance iron and unavoidable impurities. In addition, the MnB steel of the present invention may optionally contain 0.01-0.1% Ti, 0.01-0.05% Al, 0.002-0.005% N each in combination or alone. In contrast to the conventional MnB steels, in which the mechanical properties are largely determined by the C, Mn and Cr contents, contents of Cr have been dispensed with in the alloy concept according to the invention. Instead, MnB steel according to the invention contains levels of Ni in order to significantly increase the elongation at break and toughness of components produced from the steel according to the invention after a hardened state obtained by hot press forming. At the same time, the presence of Ni improves the hardenability of MnB steels according to the invention, so that the Mn contents could be reduced and the addition of critical Cr in terms of its influence on the residual ductility could be dispensed with.
Der C-Gehalt erfindungsgemäßer Stähle ist zudem so modifiziert worden, dass zu Gunsten einer verbesserten Dehnbarkeit die im Zuge des Warmpressens erzeugte Martensithärte vermindert oder das nach dem Warmpressen erhaltene Bauteile ein bainitisches Gefüge aufweist, durch dass die Zähigkeit und Bruchdehnung von aus erfindungsgemäßem Stahl erzeugten Bauteilen ebenfalls positiv beeinflusst wird. Wird auf eine erhöhte Festigkeit des erfindungsgemäßen Stahls Wert gelegt, kann im Rahmen der Erfindung der C-Gehalt im Bereich von 0,15 - 0,20 Gew.-% eingestellt werden. Für einen weniger festen, jedoch eine besonders gute Restdehnbarkeit und Zähigkeit auch nach der Warmpressverfomung und der in deren Zuge bewirkten Härtung aufweisenden Stahl haben sich demgegenüber C- Gehalte von 0,10 - 0,15 Gew.-% als zweckmäßig erwiesen.The C content of steels according to the invention has also been modified in such a way that the martensite hardness produced in the course of hot pressing is reduced or the components obtained after hot pressing have a bainitic structure in favor of improved extensibility, by virtue of the toughness and elongation at break of components produced from steel according to the invention is also positively influenced. If it is desired to increase the strength of the steel according to the invention, the C content in the range from 0.15 to 0.20% by weight can be set within the scope of the invention. For a less solid, but a particularly good residual ductility and toughness even after the hot pressing and the resulting hardening steel have in contrast C contents of 0.10 to 0.15 wt .-% proved to be useful.
Durch eine Modifizierung des Mn-Gehaltes kann zudem die Restdehnung und Härtbarkeit des erfindungsgemäßen Stahls beeinflusst werden. Dabei sind reduzierte, im Bereich von 0,8 - 1,6 Gew.-% liegende Mn-Gehalte einer verbesserten Restdehnbarkeit zuträglich, während bei Mn-Gehalten von 1,0 - 1,8 Gew.-% eine verbesserte Härtbarkeit des erfindungsgemäßen Stahls vorliegt.By modifying the Mn content, it is also possible to influence the residual elongation and hardenability of the steel according to the invention. Here are reduced, in the range of 0.8 to 1.6 wt .-% lying Mn contents of improved residual ductility beneficial, while at Mn contents of 1.0 to 1.8 wt .-% improved hardenability of the steel according to the invention is present.
Ebenso kann durch eine geeignete Einstellung des Nickel- Gehalts die Restdehnung und die Härtbarkeit des erfindungsgemäßen Stahls eingestellt werden. So führen niedrigere, im Bereich von 0,5 - 1,8 Gew.-%, insbesondere im Bereich von 0,8 - 1,5 Gew.-%, liegende Ni-Gehalte zu einer höheren Härtbarkeit und zugleich zu einer verbesserten Zähigkeit, wodurch zusammen eine verbesserte Restdehnung erzielt wird.Likewise, by a suitable adjustment of the nickel content, the residual elongation and the hardenability of the steel according to the invention can be adjusted. Thus, lower Ni contents lying in the range of 0.5-1.8% by weight, in particular in the range of 0.8-1.5% by weight, lead to higher hardenability and at the same time to improved toughness, whereby together an improved residual elongation is achieved.
Ein erfindungsgemäßer Stahl mit hoher Festigkeit und verbesserter Restdehnung nach einer im Zuge einer Warmverformung erzielten Härtung weist dementsprechend (in Gew.-%) 0,15 - 0,2 % C, 0,05 - 0,30 % Si, 0,8 - 1,6 % Mn, 0,5 - 1,0 % Ni, max. 0,015 % P, max . 0,003 % S, 0,0002 - 0,0080 % B sowie als Rest Eisen und unvermeidbare Verunreinigungen auf.A steel according to the invention with high strength and improved residual elongation after hardening achieved during hot deformation accordingly has (in% by weight) 0.15-0.2% C, 0.05-0.30% Si, 0.8. 1.6% Mn, 0.5 - 1.0% Ni, max. 0.015% P, max. 0.003% S, 0.0002 - 0.0080% B and the remainder iron and unavoidable impurities.
Ein erfindungsgemäßer Stahl mit geringerer Festigkeit, jedoch weiter verbesserter Restdehnung nach einer im Zuge einer Warmverformung erzielten Härtung weist demgegenüber (in Gew.-%) 0,10 - 0,15 % C, 0,05 - 0,30 % Si, 1,0 - 1,8 % Mn, 0,8 - 1,8 % Ni, max. 0,015 % P, max. 0,003 % S, 0,0002 - 0,0080 % B sowie als Rest Eisen und unvermeidbare Verunreinigungen auf.On the other hand, a steel according to the invention with lower strength but with further improved residual elongation after hardening achieved during hot deformation has (in% by weight) 0.10-0.15% C, 0.05-0.30% Si, 1, 0 - 1.8% Mn, 0.8 - 1.8% Ni, max. 0.015% P, max. 0.003% S, 0.0002 - 0.0080% B and the remainder iron and unavoidable impurities.
Unabhängig davon, welche der verschiedenen im Rahmen der erfindungsgemäßen Legierung möglichen Varianten zur Anwendung kommen, tritt die härtesteigernde Wirkung von Bor in einem erfindungsgemäßen Stahl insbesondere dann ein, wenn der B-Gehalt mindestens 0,0008 Gew.-% beträgt.Regardless of which of the various possible variants of the alloy according to the invention are used, the hardening effect of boron occurs in a steel according to the invention, in particular when the B content is at least 0.0008% by weight.
In Bezug auf das Stahlflachprodukt ist die oben genannte Aufgabe dementsprechend erfindungsgemäß dadurch gelöst worden, dass ein solches Stahlflachprodukt, wie Stahlband oder -blech, aus einem erfindungsgemäß zusammengesetzten Mangan-Bor-Stahl erzeugt worden ist. Bei dem erfindungsgemäßen Stahlflachprodukt kann es sich um ein warm- oder kaltgewalztes Stahlband oder -blech handeln. Dabei eignen sich erfindungsgemäß zusammengesetzte Stahlbänder oder Stahlbleche hervorragend für eine Oberflächenveredelung durch Auftrag einer metallischen Beschichtung. Diese kann beispielsweise durch Feueraluminierung oder Feuerverzinkung sowie durch eine Kombination dieser Verfahren aufgebracht werden. Darüber hinaus kann der durch die metallische Beschichtung jeweils erhaltene Korrosionsschutz zusätzlich dadurch verbessert werden, dass das erfindungsgemäße Stahlflachprodukt zusätzlich mit einer organischen oder anorganischen Beschichtung versehen wird.With regard to the flat steel product, the abovementioned object has accordingly been achieved according to the invention in that such a flat steel product, such as steel strip or sheet, has been produced from a manganese-boron steel composed according to the invention. The flat steel product according to the invention may be a hot or cold rolled steel strip or sheet. In this case, composite steel strips or steel sheets according to the invention are outstandingly suitable for surface refinement by application of a metallic coating. This can be applied for example by Feueralumierung or hot dip galvanizing and by a combination of these methods. In addition, the corrosion protection respectively obtained by the metallic coating can additionally be improved by additionally providing the flat steel product according to the invention with an organic or inorganic coating.
Für erfindungsgemäße Stahlflachprodukt können Zugfestigkeiten Rm von mindestens 1.000 MPa nach dem Warmpressen garantiert werden. Gleichzeitig liegen die Bruchdehnungswerte A80 von erfindungsgemäßen Stahlflachprodukten nach dem Warmpressen regelmäßig über 10 %.For flat steel product according to the invention, tensile strengths R m of at least 1000 MPa after hot pressing can be guaranteed. At the same time, the elongation at break values A 80 of flat steel products according to the invention after hot pressing regularly exceed 10%.
Hinsichtlich des Herstellverfahrens ist die oben genannte Aufgabe schließlich durch ein Verfahren zur Herstellung eines erfindungsgemäßen Stahlflachprodukts gelöst worden, bei dem folgende Arbeitschritte durchlaufen werden: - Erschmelzen einer erfindungsgemäß zusammengesetzten Stahlschmelze,With regard to the production process, the above-mentioned object has finally been achieved by a process for producing a flat steel product according to the invention, in which the following work steps are carried out: Melting of a molten steel composite according to the invention,
- Vergießen der Schmelze zu Brammen oder Dünnbrammen,Casting the melt into slabs or thin slabs,
- Warmwalzen der Brammen oder Dünnbrammen bei einer Warmwalzendtemperatur von 850 - 900 0C zu einem Warmband,- hot-rolling the slabs or thin slabs at a hot-rolling temperature 850-900 0 C to form a hot strip,
- Haspeln des Warmbands bei Haspeltemperaturen von 560 - 600 0C.- Coiling of the hot strip at reel temperatures of 560 - 600 0 C.
Das erhaltene Warmband kann für die weitere Verarbeitung in an sich bekannter Weise beispielsweise durch Beizen entzundert werden. Sofern das erhaltene Stahlflachprodukt unmittelbar als Warmband der Umformung zu einem Bauteil zugeführt werden soll, kann nun als Korrosionsschutz eine metallische Beschichtung in der voranstehend bereits beschriebenen Weise aufgebracht werden. Alternativ kann das Warmband nach dem erforderlichenfalls durchgeführten Beizen zu Kaltband kaltgewalzt werden. Die beim Kaltwalzen bevorzugt ohne zwischengeschaltetes Zwischenglühen erzielten Kaltwalzgrade sollten mindestens 40 % betragen, um eine vollständige Rekristallisation zu gewährleisten.The resulting hot strip can be descaled for further processing in a conventional manner, for example by pickling. If the resulting flat steel product is to be fed directly as a hot strip of the forming to a component, can now be applied as corrosion protection, a metallic coating in the manner already described above. Alternatively, the hot strip may be cold rolled after the pickling, if necessary, to cold strip. The degrees of cold rolling achieved during cold rolling, preferably without intervening intermediate annealing, should be at least 40% in order to ensure complete recrystallization.
Nachfolgend wird die Erfindung anhand von Ausführungsbeispielen erläutert.The invention will be explained below with reference to exemplary embodiments.
In einem konventionellen Konverter sind zwei erfindungsgemäße Stahlschmelzen Sl, S2 erschmolzen worden, deren Zusammensetzungen in Tabelle 1 angegeben sind. Zusätzlich ist in Tabelle 1 zum Vergleich die Zusammensetzung eines konventionellen 22MnB5-Stahls V angegeben . Die Stahlschmelzen Sl, S2 sind anschließend in einer ebenfalls konventionellen Gießwalzanlage zu Dunnbrammen vergossen worden.In a conventional converter, two inventive steel melts Sl, S2 have been melted, whose compositions are given in Table 1. In addition, in Table 1, the composition of a conventional 22MnB5 steel V is shown for comparison. The steel melts Sl, S2 have subsequently been cast into Dunnbrammen in a likewise conventional casting rolling mill.
Aus den so erhaltenen Dunnbrammen sind anschließend Warmbander warmgewalzt worden. Die Warmwalzendtemperatur betrug dabei 850 0C. Anschließend sind die erhaltenen Warmbander bei einer Haspeltemperatur gehaspelt worden, die bei 560 0C lag.Hot stripers were then hot rolled from the resulting Dunnbrammen. The hot rolling end temperature was 850 ° C. Subsequently, the resulting hot strips were rewound at a coiler temperature which was 560 ° C.
Nach dem Haspeln sind die Warmbander gebeizt und zu Kaltbandern kaltgewalzt worden. Im Hinblick auf eine Minimierung der Produktionskosten erfolgte das Kaltwalzen ohne Zwischengluhung . Der im Zuge des Kaltwalzens erreichte Kaltverformungsgrad (Kaltwalzgrad = durch das Kaltwalzen erzielte Dickenabnahme / Dicke des kaltzuwalzenden Warmbands) lag bei 40 %.After coiling, the hot strips were pickled and cold rolled to cold stripers. With a view to minimizing production costs, cold rolling was carried out without intermediate annealing. The degree of cold deformation achieved in the course of cold rolling (cold rolling degree = reduction in thickness / thickness of the cold rolled hot strip achieved by the cold rolling) was 40%.
Anschließend wurden von den erhaltenen Kaltbandern abgeteilte Proben durch Feueraluminieren mit einer metallischen Beschichtung belegt. Bei einer ersten Probe bestand der metallische Überzug dabei aus 89 - 92 Gew.-% Al, Rest Si. Eine zweite Probe wurde mit einem Überzug, der 55 Gew.-% Al, 43,4 Gew.-% Zn und 1,6 Gew.-% Si enthielt, feueraluminiert .Subsequently, samples separated from the cold-rolled strips obtained were coated with a metallic coating by means of fire aluminizing. In the case of a first sample, the metallic coating consisted of 89-92% by weight of Al, balance Si. A second sample was fire-aluminized with a coating containing 55% by weight of Al, 43.4% by weight of Zn and 1.6% by weight of Si.
Andere von den erhaltenen Kaltbandern abgeteilte Proben sind einer Feuerverzinkung unterzogen worden, bei der eine erste Probe mit einer Reinzinkschicht (Zn-Gehalt mindestens 99 Gew.-%) und eine zweite Probe mit einer Schicht aus 95 Gew.-% Zn, Rest Al belegt worden ist. Eine dritte Probe wurde in an sich ebenso bekannter Weise durch Galvanealing mit einer Reinzinkschicht beschichtet. Die so behandelten Proben sind durch Warmpressformen zu Karosseriebauteilen umgeformt worden. Die so erhaltenen Bauteile wiesen Zugfestigkeiten von jeweils mehr als 1.000 MPa und eine Bruchdehnung A80 von mindestens 10 % auf. Durch Auftrag eines durch Kataphorese-Tauch-Lackierung aufgebrachten Lackschicht mit anschließender Trocknung konnte die untere Streckgrenze um mindestens 80 MPa gesteigert werden, ohne dass die Festigkeit und Bruchdehnung der Bauteile sich änderte.Other samples separated from the cold-rolled strips obtained have been subjected to hot-dip galvanizing, in which a first sample is coated with a zinc-zinc layer (Zn content at least 99% by weight) and a second sample with a layer of 95% by weight Zn, balance Al has been. A third sample was coated in a manner known per se by galvanic plating with a pure zinc coating. The samples thus treated have been hot stamped into body parts. The components thus obtained had tensile strengths of more than 1,000 MPa and an elongation at break A 80 of at least 10%. By applying a paint layer applied by cataphoresis dip coating with subsequent drying, the lower yield strength could be increased by at least 80 MPa, without the strength and elongation at break of the components changed.
Abhängig von der jeweiligen Temperaturführung im für die Warmpressverformung verwendeten Werkzeug lag in den erhaltenen Bauteilen ein martensitisches, ein bainitisches oder ein gemischt martensitisches-bainitisches Gefüge vor.Depending on the respective temperature control in the tool used for the hot-pressing deformation, a martensitic, a bainitic or a mixed martensitic-bainitic structure was present in the components obtained.
In Diag. 1 sind die für die Stähle Sl, S2 die nach dem Jominiy-Test berechneten Härteverläufe dem Härteverlauf des konventionell zusammengesetzten Stahls V gegenüber gestellt. Dabei ist die jeweilige Härte H über den jeweiligen Abstand A zur abgeschreckten Fläche aufgetragen. In Diag. 1, the hardness profiles of the steels Sl, S2 compared to the hardness curve of the conventionally assembled steel V are compared with those calculated according to the Jominiy test. The respective hardness H is plotted over the respective distance A to the quenched surface.
Figure imgf000012_0001
Figure imgf000012_0001
Tabelle 1 Table 1

Claims

P A T E N T A N S P R Ü C H E PATENT APPLICATIONS
1. Mangan-Bor-Stahl, der (in Gew.-%)1. Manganese-boron steel containing (in% by weight)
C: 0, 1 - 0,20 %,C: 0, 1 - 0,20%,
Si: 0, 05 - 0,30 %,Si: 0, 05-0.30%,
Mn: 0, 8 - 11 , Q ö 215-,Mn: 0, 8 - 11, Q ö 215-,
Ni: 0, 5 - 11 , Q ö 215-,Ni: 0, 5 - 11, Q ö 215-,
P: < 0, 015 %,P: <0, 015%,
S: < 0,003 %,S: <0.003%,
B: 00,, 000002 - 0,0080 %, sowie wahlweise eines oder mehrere der folgenden Elemente Ti, Al und N nach folgender Maßgabe:B: 00 ,, 000002 - 0.0080%, and optionally one or more of the following elements Ti, Al and N as follows:
Ti: 0, 01 - 0,1 %,Ti: 0, 01 - 0.1%,
Al: 0,01 - 0,05 %,Al: 0.01-0.05%,
N: 0, 002 - 0, 005 %, Rest Eisen und unvermeidbare Verunreinigungen enthält,N: 0, 002 - 0, 005%, the remainder contains iron and unavoidable impurities,
2. Mangan-Bor-Stahl nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t, d a s s er2. manganese-boron steel according to claim 1, d a d u c h e c e n e c e s t e, s e s s
0,15 - 0,20 Gew.-% Kohlenstoff enthält.0.15-0.20% by weight of carbon.
3. Mangan-Bor-Stahl nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t, d a s s er3. Manganese-boron steel as claimed in claim 1, characterized in that it is
0,10 - 0,15 Gew.-% Kohlenstoff enthält. 0.10 - 0.15 wt .-% carbon.
4. Mangan-Bor-Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a s s er 0,8 - 1,6 Gew.-% Mangan enthält.4. manganese-boron steel according to any one of the preceding claims, d a d u c c h e c e n e c e s t e, if s s it 0.8 to 1.6 wt .-% manganese.
5. Mangan-Bor-Stahl nach einem der Ansprüche 1 bis 3, d a d u r c h g e k e n n z e i c h n e t, d a s s er 1,0 - 1,8 Gew.-% Mangan enthält.5. manganese-boron steel according to any one of claims 1 to 3, d a d u c h e c e n e c e s t e, s e s it 1.0 to 1.8 wt .-% manganese.
6. Mangan-Bor-Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a s s er 0,5 - 1,0 Gew.-% Nickel enthält.6. manganese-boron steel according to any one of the preceding claims, d a d u c c h e c e n e c e s t e, s t he s 0.5 to 1.0 wt .-% nickel.
7. Mangan-Bor-Stahl nach einem der Ansprüche 1 bis 5, d a d u r c h g e k e n n z e i c h n e t, d a s s er 0,8 - 1,8 Gew.-% Nickel enthält.7. manganese-boron steel according to one of claims 1 to 5, d a d u c h e c e n e c e s t e, if it contains 0.8 to 1.8 wt .-% nickel.
8. Mangan-Bor-Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a s s er mindestens 0,0008 Gew.-% Bor enthält.8. Manganese-boron steel according to one of the preceding claims, characterized in that it contains at least 0.0008 wt .-% of boron.
9. Stahlflachprodukt, hergestellt aus einem gemäß einem der Ansprüche 1 bis 8 zusammengesetzten Mangan-Bor- Stahl.9. flat steel product, prepared from a composite according to one of claims 1 to 8 manganese-boron steel.
10. Stahlflachprodukt nach Anspruch 9, d a d u r c h g e k e n n z e i c h n e t, d a s s es durch Auftrag einer metallischen Beschichtung oberflächenveredelt ist. 10. Flat steel product according to claim 9, characterized in that it is surface-treated by applying a metallic coating.
11. Stahlflachprodukt nach Anspruch 9 oder 10, d a d u r c h g e k e n n z e i c h n e t, d a s s es nach dem Warmpressen eine Zugfestigkeit Rm von mindestens 1.000 MPa aufweist.11. Flat steel product according to claim 9 or 10, characterized in that it has a tensile strength R m of at least 1,000 MPa after hot pressing.
12. Stahlflachprodukt nach einem der Ansprüche 9 bis 11, d a d u r c h g e k e n n z e i c h n e t, d a s s es nach dem Warmpressen eine Bruchdehnung A80 von mehr als 10 % besitzt.12. Flat steel product according to one of claims 9 to 11, characterized in that it has an elongation at break A 80 of more than 10% after hot pressing.
13. Verfahren zur Herstellung eines gemäß einem der13. A method for producing a according to one of
Ansprüche 9 bis 12 beschaffenen Stahlflachprodukts, umfassend folgende Arbeitschritte:Claims 9 to 12 procured flat steel product, comprising the following steps:
- Erschmelzen einer Stahlschmelze mit einer gemäß einem der Ansprüche 1 bis 8 ausgebildeten Zusammensetzung,Melting a molten steel having a composition according to any one of claims 1 to 8,
- Vergießen der Schmelze zu Brammen oder Dünnbrammen,Casting the melt into slabs or thin slabs,
- Warmwalzen der Brammen oder Dünnbrammen bei einer Warmwalzendtemperatur von 850 - 900 0C zu einem Warmband,- hot-rolling the slabs or thin slabs at a hot-rolling temperature 850-900 0 C to form a hot strip,
- Haspeln des Warmbands bei Haspeltemperaturen von 560 - 600 0C.- Coiling of the hot strip at reel temperatures of 560 - 600 0 C.
14. Verfahren nach Anspruch 13, d a d u r c h g e k e n n z e i c h n e t, d a s s das Warmband nach dem Warmwalzen entzundert wird.14. The method of claim 13, wherein the hot strip is descaled after hot rolling.
15. Verfahren nach Anspruch 13 oder 14, d a d u r c h g e k e n n z e i c h n e t, d a s s das Warmband nach dem Warmwalzen zu einem Kaltband kaltgewalzt wird. 15. The method according to claim 13 or 14, characterized in that the hot strip is cold rolled after hot rolling to a cold strip.
16. Verfahren nach Anspruch 15, d a d u r c h g e k e n n z e i c h n e t, d a s s das Kaltwalzen ohne Zwischenglühen durchgeführt wird.16. The method of claim 15, wherein the cold rolling is carried out without intermediate annealing.
17. Verfahren nach einem der Ansprüche 15 oder 16, d a d u r c h g e k e n n z e i c h n e t, d a s s der beim Kaltwalzen erzielte Kaltwalzgrad mindestens 40 % beträgt.17. The method according to claim 15 or 16, wherein a cold rolling degree achieved during cold rolling is at least 40%.
18. Verfahren nach einem der Ansprüche 14 bis 17, d a d u r c h g e k e n n z e i c h n e t, d a s s das entzunderte Warmband oder das Kaltband durch eine metallische Beschichtung oberflächenveredelt wird.18. The process according to claim 14, wherein the descaled hot strip or the cold strip is surface-finished by a metallic coating.
19. Verfahren nach Anspruch 18, d a d u r c h g e k e n n z e i c h n e t, d a s s das entzunderte Warmband oder das Kaltband feueraluminiert wird.19. The method of claim 18, wherein: the descaled hot strip or the cold strip is flame-aluminized.
20. Verfahren nach Anspruch 18, d a d u r c h g e k e n n z e i c h n e t, d a s s das entzunderte Warmband oder das Kaltband feuerverzinkt wird.20. The method of claim 18, wherein the descaled hot strip or cold strip is hot dip galvanized.
21. Verfahren nach einem der Ansprüche 18 bis 20, d a d u r c h g e k e n n z e i c h n e t, d a s s das mit der metallischen Beschichtung versehene entzunderte Warmband oder Kaltband mit einer organischen oder anorganischen Beschichtung versehen wird. 21. The method of claim 18, wherein the descaled hot strip or cold strip provided with the metallic coating is provided with an organic or inorganic coating.
PCT/EP2007/055130 2006-06-07 2007-05-25 Manganese boron steel, flat products produced from such steel, and production method WO2007141152A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP06115075A EP1865086B1 (en) 2006-06-07 2006-06-07 Use of a steel flat product produced from a manganese boron steel and method of its production
EP06115075.1 2006-06-07

Publications (1)

Publication Number Publication Date
WO2007141152A1 true WO2007141152A1 (en) 2007-12-13

Family

ID=36685928

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/055130 WO2007141152A1 (en) 2006-06-07 2007-05-25 Manganese boron steel, flat products produced from such steel, and production method

Country Status (4)

Country Link
EP (1) EP1865086B1 (en)
AT (1) ATE477348T1 (en)
DE (1) DE502006007636D1 (en)
WO (1) WO2007141152A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9057419B2 (en) 2010-05-31 2015-06-16 Iwis Motorsysteme Gmbh & Co., Kg Link chain with link plates made of boron-manganese steel
US10118646B2 (en) * 2016-01-18 2018-11-06 Ford Global Technologies, Llc Chassis-subframe arrangement for improving crash protection

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016193268A1 (en) * 2015-06-03 2016-12-08 Salzgitter Flachstahl Gmbh Deformation-hardened component made of galvanized steel, production method therefor and method for producing a steel strip suitable for the deformation-hardenening of components
WO2017006144A1 (en) 2015-07-09 2017-01-12 Arcelormittal Steel for press hardening and press hardened part manufactured from such steel
WO2018220430A1 (en) 2017-06-02 2018-12-06 Arcelormittal Steel sheet for manufacturing press hardened parts, press hardened part having a combination of high strength and crash ductility, and manufacturing methods thereof
WO2020002285A1 (en) 2018-06-26 2020-01-02 Tata Steel Nederland Technology B.V. Cold-rolled martensite steel with high strength and high bendability and method of producing thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62287012A (en) * 1986-06-03 1987-12-12 Kobe Steel Ltd Production of low-temperature reinforcing bar having excellent weldability
JPH05345917A (en) * 1992-06-15 1993-12-27 Nippon Steel Corp Production of high strength hot rolled steel plate
JP2001107190A (en) * 1999-10-07 2001-04-17 Nkk Corp High-tensile steel for bolt and nut excellent in seaside weather resistance
EP1160346A1 (en) * 1999-02-22 2001-12-05 Nippon Steel Corporation High strength galvanized steel plate excellent in adhesion of plated metal and formability in press working and high strength alloy galvanized steel plate and method for production thereof
JP2005336541A (en) * 2004-05-26 2005-12-08 Nippon Steel Corp Low yr high tensile strength steel plate and its production method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2780984B1 (en) 1998-07-09 2001-06-22 Lorraine Laminage COATED HOT AND COLD STEEL SHEET HAVING VERY HIGH RESISTANCE AFTER HEAT TREATMENT
JP3993831B2 (en) 2002-11-14 2007-10-17 新日本製鐵株式会社 Steel sheet with excellent curability and impact properties after hot forming and method of using the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62287012A (en) * 1986-06-03 1987-12-12 Kobe Steel Ltd Production of low-temperature reinforcing bar having excellent weldability
JPH05345917A (en) * 1992-06-15 1993-12-27 Nippon Steel Corp Production of high strength hot rolled steel plate
EP1160346A1 (en) * 1999-02-22 2001-12-05 Nippon Steel Corporation High strength galvanized steel plate excellent in adhesion of plated metal and formability in press working and high strength alloy galvanized steel plate and method for production thereof
JP2001107190A (en) * 1999-10-07 2001-04-17 Nkk Corp High-tensile steel for bolt and nut excellent in seaside weather resistance
JP2005336541A (en) * 2004-05-26 2005-12-08 Nippon Steel Corp Low yr high tensile strength steel plate and its production method

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
M. SUEHIRO, K. KUSUMI, T. MIYAKOSHI, J. MAKI, M. OHGAMI: "Properties of aluminium-coated steels for hot forming", NIPPON STEEL TECHNICAL REPORT, no. 88, July 2003 (2003-07-01), pages 16 - 21, XP002393305 *
PATENT ABSTRACTS OF JAPAN vol. 012, no. 181 (C - 499) 27 May 1988 (1988-05-27) *
PATENT ABSTRACTS OF JAPAN vol. 018, no. 191 (C - 1186) 4 April 1994 (1994-04-04) *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 21 3 August 2001 (2001-08-03) *
PATENT ABSTRACTS OF JAPAN vol. 2003, no. 12 5 December 2003 (2003-12-05) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9057419B2 (en) 2010-05-31 2015-06-16 Iwis Motorsysteme Gmbh & Co., Kg Link chain with link plates made of boron-manganese steel
US10118646B2 (en) * 2016-01-18 2018-11-06 Ford Global Technologies, Llc Chassis-subframe arrangement for improving crash protection

Also Published As

Publication number Publication date
DE502006007636D1 (en) 2010-09-23
ATE477348T1 (en) 2010-08-15
EP1865086A1 (en) 2007-12-12
EP1865086B1 (en) 2010-08-11

Similar Documents

Publication Publication Date Title
EP2553133B1 (en) Steel, flat steel product, steel component and method for producing a steel component
DE112006003169B4 (en) Steel sheets for hot press forming with excellent heat treatment and impact properties, hot pressed parts produced therefrom and process for their production
EP2383353B1 (en) High tensile steel containing Mn, steel surface product made from such steel and method for producing same
DE102008035714B9 (en) Hot stamping steel sheet having low-temperature tempering property, methods for producing the same, methods of producing parts using the same, and parts made therewith
EP2449138B1 (en) Process of manufacturing a part from an air hardenable steel and the part manufactured by the process
DE602004010699T2 (en) Cold rolled steel sheet having a tensile strength of 780 MPa or more, excellent local moldability and suppressed weld hardness increase
EP2848709A1 (en) Method for producing a steel component with an anti-corrosive metal coating and steel component
EP3215656B1 (en) Method for producing an anti-corrosion coating for hardenable steel sheets and anti-corrosion layer for hardenable steel sheets
WO2009021897A1 (en) Dual-phase steel, flat product made of such dual-phase steel and method for producing a flat product
WO2009047183A1 (en) Method for the production of a steel component by thermoforming, and steel component produced by thermoforming
DE19610675C1 (en) Dual phase steel for cold rolled sheet or strip - contg. manganese@, aluminium@ and silicon
EP1939308A1 (en) Method for manufacturing a component through hot press hardening and highly rigid component with improved breaking strain
DE2334974A1 (en) HARDENABLE AND HIGH-STRENGTH STEEL FOR COLD-ROLLED PLATE
WO2008052918A1 (en) Method for manufacturing flat steel products from a steel forming a martensitic structure
EP3504349A1 (en) Method for producing a high-strength steel strip with improved properties for further processing, and a steel strip of this type
DE102020134324A1 (en) PRESS-HARDENING STEEL WITH HIGH OXIDATION RESISTANCE
EP1865086B1 (en) Use of a steel flat product produced from a manganese boron steel and method of its production
EP3642371A1 (en) Method for producing a steel component provided with a metallic coating protecting against corrosion
EP3512968B1 (en) Method for producing a flat steel product made of a manganese-containing steel, and such a flat steel product
WO2008052921A1 (en) Method for manufacturing flat steel products from a multiphase steel alloyed with silicon
DE102008022401B4 (en) Process for producing a steel molding having a predominantly bainitic structure
DE69909305T2 (en) Ultra-low carbon steel composition, process for producing this bake hardenable steel, and the product produced
EP1399598A1 (en) Method for producing high-strength cold-formed steel products from a hot rolled strip, said products exhibiting good malleability
EP3872206B1 (en) Post-treated cold rolled steel sheet product and method of manufacturing a post-treated cold rolled steel sheet product
EP3894603B1 (en) Method for producing a coated steel flat product, method for producing a steel component and coated steel flat product ii

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07729554

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
122 Ep: pct application non-entry in european phase

Ref document number: 07729554

Country of ref document: EP

Kind code of ref document: A1