EP2465961B1 - Feuilles d'acier très résistantes et leurs procédés de production - Google Patents

Feuilles d'acier très résistantes et leurs procédés de production Download PDF

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Publication number
EP2465961B1
EP2465961B1 EP11193464.2A EP11193464A EP2465961B1 EP 2465961 B1 EP2465961 B1 EP 2465961B1 EP 11193464 A EP11193464 A EP 11193464A EP 2465961 B1 EP2465961 B1 EP 2465961B1
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EP
European Patent Office
Prior art keywords
steel sheet
phase
martensite
temperature
space factor
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EP11193464.2A
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German (de)
English (en)
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EP2465961A1 (fr
Inventor
Kenji Saito
Tomokazu Masuda
Masaaki Miura
Yoichi Mukai
Shushi Ikeda
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Kobe Steel Ltd
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Kobe Steel Ltd
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Priority claimed from JP2007144466A external-priority patent/JP5201653B2/ja
Priority claimed from JP2007144705A external-priority patent/JP4291860B2/ja
Priority claimed from JP2007145987A external-priority patent/JP5234893B2/ja
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Publication of EP2465961A1 publication Critical patent/EP2465961A1/fr
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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
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • C22C38/04—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
    • C22C38/06—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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

Definitions

  • the present invention relates to a high strength steel sheet for which high press formability is required, typically including steel sheets for automobiles, particularly to a high strength steel sheet with both elongation and stretch-flanging performance and a method for manufacturing the same.
  • High strength steel sheets which are generally used by being press-molded, are used in industrial product such as automobiles, electric devices and industrial machines. Since high strength steel sheets are used for the purpose of lightening industrial products, they need not only have high strength, but also have the ability to form various configurations of the products. Accordingly, it is required for high strength steel sheets to have excellent press formability. To meet this requirement, high-strength steel sheets having excellent elongation and stretch-flanging performance, which are necessary for improving press formability, are required.
  • Examples of known steels having such characteristics include dual phase steel (DP steel) whose metal structure is composed of a ferrite phase and a martensite phase, as described in Patent document 1. Since this DP steel can ensure ductility (elongation) due to its soft ferrite and strength due to its rigid martensite, it has both strength and elongation (in particular, uniform elongation) . However, because of the coexistence of soft ferrite and rigid martensite, distortion (stress) is concentrated at the interface of the two phases when deformed, and therefore the interface is likely to serve as the starting point of rupture, thereby disadvantageously preventing ensuring stretch-flanging performance (local elongation).
  • Examples of steel sheets which expectedly have ductility (especially, uniform elongation) higher than those of DP steels include TRIP steels utilizing the TRIP (Transformation Induced Plasticity) phenomenon, as described in Patent document 2.
  • TRIP steel is a steel sheet in which uniform elongation is increased by transforming retained austenite into martensite during deformation (working-induced transformation).
  • martensite which has been transformed from retained austenite in the TRIP steel is extremely hard, it likely serves as the starting point of rupture, lowering the stretch-flanging performance of the steel sheet.
  • Other methods of improving the stretch-flanging performance of the high strength steel sheets include that in which the metal structure is single-phase structure and localization of process distortion is suppressed by homogenizing the in the metal structure, and that in which a difference in strength between a soft phase having a multi-phase metal structure and a hard phase is reduced.
  • martensite single-phase structure steel sheet Since martensite single-phase structure steel sheet has a uniform structure, it is known as a steel sheet which has both strength and stretch-flanging performance. However, the martensite single-phase structure steel sheet disadvantageously has low ductility, and insufficient elongation.
  • Patent document 3 discloses a high-stretch-strength cold-rolled steel sheet in which martensite single-phase structure is achieved by justifying the composition and heat treatment conditions of the steel sheet, and tensile strength is 880 to 1170 MPa. That is, the high-stretch-strength cold-rolled steel sheet of Patent document 3 is produced by heating and retaining a steel sheet having a predetermined composition range at 850°C, which is normally reachable temperature industrially, to transform the steel sheet into austenite, and then rendering it a martensite single-phase structure.
  • a steel sheet of a martensite single-phase structure produced by this invention has a tensile strength of 880 to 1170 MPa, and thus has excellent stretch-flanging performance. However, it has elongation EL (%) lower than 8% and thus has low ductility. In the high strength steel sheet of the invention of Patent document 3, if ductility is improved, press formability can be further improved.
  • Patent document 4 discloses a method for manufacturing a high tensile strength steel sheet, in which a steel sheet in which the ratio by volume of a low-temperature transformation phase comprising a martensite phase and others and a retained austenite phase is 90% or higher of the entire metal structure is heated and retained to produce a two phase region: a ferrite phase and an austenite phase, a metal structure comprising a fine ferrite phase which has succeeded the laths of the low-temperature transformation phase and the austenite phase is provided, and finally the steel sheet is given such a metal structure that comprises ferrite and the low-temperature transformation phase finely dispersed in the form of laths.
  • Patent document 4 since the steel sheet produced by the steelmaking method disclosed in Patent document 4 has a relatively high cooling stop temperature in the steelmaking process, a large amount of bainite is deposited, while a large amount of retained austenite also remains therein, and therefore the steel sheet has excellent ductility, but has insufficient stretch-flanging performance.
  • Patent document 1 Japanese Unexamined Patent Application Publication (JP-A) No. S55-122820
  • Patent document 2 Japanese Patent document 2
  • JP-A-S60-43425 Japanese Patent No.
  • JP-A-2005-272954 JP 2005-213603 discloses a cold rolled steel plate which comprises 0.03 to 0.2% C, ⁇ 2% Si, 0.5 to 3% Mn, ⁇ 0.1% P, ⁇ 0.01% S, 0.01 to 0.1% Sol Al, ⁇ 0.005% N and the balance Fe, and has two phases of ferrite and martensite with ⁇ 2.0 ⁇ m grain size of the ferrite.
  • the steel plate is manufactured by hot rolling a steel having the above composition at a temperature equal to or higher than the Ar 3 point for finish rolling, cooling from the finish temperature to ⁇ 550°C at ⁇ 70°C/s cooling rate, winding up at ⁇ 500°C, heat treating the steel at a temperature in a range from 600°C to the Ac 1 point, subjecting the steel to acid pickling and cold rolling, then keeping the steel at a temperature in a range from the Ac 1 point to the Ac 3 point for 10 seconds,; rapidly cooling to 100°C at a cooling rate of ⁇ 100°C/s and tempering at 300 to 500°C for recrystallization annealing/tempering treatment.
  • JP 2001-92768 discloses a steel plate having a composition containing 0.05 to 0.20% C, 0.3 to 1.8% Si, 1.0 to 3.0% Mn and ⁇ 0.005% S, which is subjected to a first stage in which the same is subjected to primary heating treatment in the temperature range of (the Ac 3 transformation point -50 °C) to (the Ac 3 transformation point + 100 °C) and is thereafter rapidly cooled to the M s point or less, a second stage in which the same is subjected to secondary heating treatment in a two phase region and is rapidly cooled to 500 °C or less and a third stage in which the same is subjected to hot dip galvanizing treatment and is rapidly cooled to 300 °C in succession.
  • the present invention has been made to solve such a problem, and an object thereof is to provide a high strength steel sheet excellent in both elongation and stretch-flanging performance and a method for manufacturing the same.
  • Another object of the present invention is to provide a high strength steel sheet having a tensile strength of 780 MPa or higher, in which elongation and stretch-flanging performance are both improved, and a method for manufacturing the same.
  • the high strength steel sheet of the present invention is constituted of, in percent by mass, C: 0.05 to 0.3%, Si: 0.01 to 3%, Mn: 0.5 to 3.0%; Al: 0.01 to 0.1%, at least an element selected from Ti, Nb, V and Zr in an amount of 0.01 to 1% in total, and optionally, Ni and/or Cu in an amount of 1% or lower in total, Cr: 2% or less, Mo: 1% or less, B: 0.0001 to 0.005%, Ca and/or REM in an amount of 0.003% or lower in total, and the remainder comprising iron and inevitable impurities, has a space factor of martensite phase, wherein the structure which is a main part of the metal structure is the martensite phase and a ferrite phase; the space factor of the martensite phase is 70 to 95%; the space factor of the ferrite phase is 5 to 25%; the total sum of the martensite phase and the ferrite phase is 80% or higher, and the mean grain size of the martensite phase is
  • the term "equivalent of a circle diameter” means the diameter of an anticipated circle having the same area as the grains of tempered martensite, and is determined by subjecting a structure picture to image analysis.
  • the term "space factor” means the percentage by volume, and is determined by corroding a structure observation test piece with nital, observing the test piece with an optical microscope (1000 times), and by subjecting the observed structure picture to image analysis.
  • annealed bainite is observed as a body centered cubic structure in terms of a crystal structure.
  • Ac 3 point is a temperature at which a two-phase region comprising an austenite phase and a ferrite phase transforms into an austenite single-phase region that is stable at high temperatures in a temperature raising step.
  • the structure which is the main part of the metal structure is a martensite phase and a ferrite phase; the space factor of the martensite phase is 70 to 95% (meaning “% by volume", and so on); the space factor of the ferrite phase is 5 to 25%; the total sum of the martensite phase and the ferrite phase is 80% or higher, and the mean grain size of the martensite phase is 10 ⁇ m or smaller in terms of the equivalent of a circle diameter and wherein the structure is allowed as the rest of the metal structure containing bainite, pearlite and retained austenite phase.
  • the method for manufacturing the high strength steel sheet according to the present invention is for manufacturing a high strength steel sheet of the present invention by using, as a material steel sheet, a steel sheet in which the total space factor of the martensite phase and/or bainite phase in the entire metal structure is 90% or higher and the grain size of the former austenite is 20 ⁇ m or smaller in terms of the equivalent of a circle diameter, heating and retaining the steel sheet at a temperature of (Ac 3 point -100°C) or higher but not higher than Ac 3 point for 1 to 2400 seconds, then cooling the steel sheet to a transformation start temperature of martensite, Ms point, or lower at an average cooling rate of 10°C/sec. or higher, and subsequently conducting a heat treatment in which the steel sheet is heated and retained at a temperature of 300 to 550°C for 60 to 1200 seconds.
  • a material steel sheet a steel sheet in which the total space factor of the martensite phase and/or bainite phase in the entire metal structure is 90% or higher and the grain size of the former
  • the high strength steel sheet according to the present invention may comprise, in addition to the above-mentioned basic components, any of the element groups (a) to (e) described below, or one or more elements selected from a plurality of groups within a range defined for each element group.
  • the present invention it is also possible to achieve a high strength steel sheet which has excellent elongation and stretch-flanging performance et the same time by designing the steel sheet especially for a dual phase steel sheet mainly composed of a ferrite phase and martensite, ensuring high strength of the steel sheet as a whole, and appropriately controlling the space factors of especially the ferrite phase and martensite and the mean grain sizes of the same.
  • the inventors of the present invention studied the requirements for obtaining both strength and elongation, which are the features of a dual phase steel sheet (DP steel sheet), and also stretch-flanging performance by presupposingly using this DP steel sheet comprising the ferrite phase and martensite, from various angles.
  • a very fine ferrite + martensite dual structure can be obtained by subjecting a steel sheet having a fine lath-shaped structure (martensite and/or bainite) as a material steel sheet (that is, as an initial structure) to annealing (hereinafter referred to as "dual-phase range annealing") in a dual-phase range (ferrite +austenite range) .
  • a steel sheet having such a structure has good elongation and stretch-flanging performance.
  • ferrite produced by the dual-phase range annealing is finely dispersed, and the growth of austenite during the dual-phase range annealing is suppressed by its pinning effect. Accordingly, its structure after hardening becomes a very fine ferrite + martensite structure.
  • crystal grain micronizing elements such as Ti, Nb, V and Zr are added to the steel sheet as chemical components, whereby further micronization of the structure can be achieved. The thus-obtained dual phase steel sheet is imparted further improved elongation and stretch-flanging performance.
  • the high strength steel sheet of the present invention is a dual phase steel sheet which is mainly composed of a ferrite phase and martensite.
  • the space factors of these phases to the entire structure are adjusted appropriately. That is, in the high strength steel sheet of the present invention, the space factors of the ferrite phase and martensite are 5 to 25% and 70 to 95%, respectively.
  • a preferable space factor of the ferrite phase is 7% or higher.
  • a preferable space factor of the martensite phase is not higher than 85%.
  • space factor means the ratio (% by volume) of each phase constituting a metal structure in the steel material to the entire structure, and the space factors of the ferrite phase and martensite can be determined by corroding a steel material with nital, observing the material with an optical microscope (1000 times), and then subjecting the material to image analysis.
  • the mean grain size of the above ferrite phase is 3 ⁇ m or smaller in terms of the equivalent of a circle diameter, and that the mean grain size of the martensite phase is 6 ⁇ m or smaller in terms of the equivalent of a circle diameter. If these sizes are increased, elongation and stretch-flanging performance are lowered.
  • the "mean grain sizes" of these phases are determined, for example, by measuring the grain sizes of twenty grains by observing the structure using an optical microscope and FE/SEM-EBSP, and averaging the measurements.
  • the dual phase steel sheet according to the present invention is composed of a ferrite phase and martensite as its main structure, but it is not necessarily 100% composed of these phases, and it is also allowed that at least the total sum is 80% or higher, in terms of space factor, due to the intention that it is merely the main part, and that bainite, pearlite, retained austenite and the like are contained.
  • a preferable composition of constituents considering the strength (590 MPa or higher as tensile strength TS) and other points is as follows: C: 0.05 to 0.3%; Si: 0.01 to 3%; Mn: 0.5 to 3.0%; Al: 0.01 to 0.1%; at least one element selected from the group consisting of Ti, Nb, V and Zr: 0.01 to 1% in total; and iron and inevitable impurities as the remainder.
  • the reason for the definition of these preferable ranges is as follow:
  • the amount of C contained is preferably 0.05% or higher. From the perspective of increasing strength, the higher the amount of C contained, the better. However, if the amount of C is excessively high, a large amount of retained austenite which deteriorates stretch-flanging performance is produced, and weldability is also adversely affected. Therefore, the amount is preferably 0.3% or lower. A more preferable lower limit of the amount of C contained is 0.07%, and a more preferable upper limit is 0.25%.
  • Si is an element which effectively acts as a deoxidizing element when steel is melted, and effectively increases strength without deteriorating the ductility of steel. It also acts to suppress deposition of coarse carbide which deteriorates stretch-flanging performance. In order to perform these effects effectively, it is preferably contained in an amount of 0.01% or higher. However, since the effect of adding Si is saturated in an amount of about 3%, A preferable upper limit is set to 3%. A more preferable lower limit of the amount of Si contained is 0.1%, and a more preferable upper limit is 2.5%.
  • Mn is an element useful in increasing the hardening characteristics of the steel sheet to ensure high strength. To perform such an effect, it is preferably contained in an amount of 0.5% or higher. However, when the amount of Mn contained is excessively high, ductility is lowered and therefore processability is adversely affected. For this reason, the upper limit is set to 3.0%. A more preferable amount of Mn contained is 0.7% or higher but not higher than 2.5% or lower.
  • Al is an element having a deoxidation effect, and when Al deoxidation is performed, it needs to be added in an amount of 0.01% or higher.
  • the upper limit is set to 0.1%.
  • a more preferable amount of Al contained is 0.03% or higher but not higher than 0.08%.
  • These elements have the action to form precipitates such as carbide, nitride and carbonitride together with C and N to contribute to increased strength, and micronize crystal grains during hot rolling to increase elongation and stretch-flanging performance.
  • Such effects are effectively performed when they are added in an amount of 0.01% or higher in total (of one or more members).
  • a more preferable amount of these elements contained is 0.03% or higher, however, when the amount is excessively high, elongation and stretch-flanging performance are deteriorated rather than improved. Therefore, the amount is to be limited to 1% or lower, and more preferably 0.7% or lower.
  • Preferable basic components in the dual phase steel sheet of the present invention are as stated above, and the remainder is iron and inevitable impurities.
  • inevitable impurities include steel raw materials, and P, S, N, 0 and others which can get into steel during the manufacturing process of the materials, among others.
  • Ni and/or Cu 1% or lower (not including 0%) in total
  • Cr 2% or lower (not including 0%) and/or Mo: 1% or lower (not including 0%)
  • B 0.0001 to 0.005%
  • Ca and/or REM 0.003% or lower (not including 0%) in total, among others.
  • the characteristics of the steel sheet are further improved depending on the types of the components contained. The reason for setting the range of these elements when contained is as follows.
  • Both Cr and Mo are elements effective in stabilizing the austenite phase, and facilitating the generation of the low-temperature transformation phase in the course of cooling. Although their effects increase as their amount contained is increased, if they are contained in an excessively high amount, ductility is deteriorated. Therefore, the amount of Cr is to be limited to 2% or lower (more preferably 1.5% or lower), and the amount of Mo is to be limited to 1% or lower (more preferably 0.7% or lower).
  • B is an element effective in improving hardening characteristics, and increasing the strength of the steel sheet when added in a minute amount. To exhibit such an effect, it is preferably contained in an amount of 0.0001% or higher. However, when the amount of B contained is excessively high and is higher than 0.005%, crystal grain boundaries may be embrittled and cracks may occur during rolling.
  • Ca and REM are elements effective in controlling the form of sulfide in the steel and improving processability.
  • the material steel sheet used in the present invention has a space factor of the low-temperature transformation phase of 90% or higher.
  • This low-temperature transformation phase may be constituted only by martensite or bainite.
  • the space factor of the low-temperature transformation phase is lower than 90%, and the material steel sheet is heated to a 2-phase range of the ferrite phase and austenite phase (dual-phase range annealing) in the annealing step (final annealing step) described later, a coarse ferrite phase and an austenite phase are produced. Therefore, the fine ferrite phase and martensite mentioned above cannot be obtained in the final structure. As a result, stretch-flanging performance cannot be improved.
  • a material steel sheet having space factor of the low-temperature transformation phase of 90% or higher can be produced by the following steps: First, a steel slab adjusted to meet the composition of chemical constituents as mentioned above is hot-rolled in such a manner that the finishing rolling temperature is higher than Ac 3 point. Second, the material steel sheet is cooled to a temperature lower than a martensite transformation start temperature, Ms point (temperature at which the austenite phase starts to transform into martensite), at an average cooling rate of 10°C/sec. or higher, and is then wound up, giving a material steel sheet having a space factor of martensite of 90% or higher.
  • Ms point temperature at which the austenite phase starts to transform into martensite
  • a material steel sheet which is mainly composed of bainite and has a space factor of the low-temperature transformation phase of 90% or higher is obtained by cooling the material steel sheet to a bainite transformation temperature after the hot rolling, at an average cooling rate of 10°C/sec. or higher and winding up the same.
  • the finishing rolling temperature is Ac 3 point or lower or the cooling rate after the hot rolling is 10°C/sec. or lower, a ferrite phase is likely to be produced during cooling after the hot rolling, and therefore the space factor of the low-temperature transformation phase after the hot rolling is not 90% or higher.
  • the grain size of austenite is micronized by utilizing the pinning effect by finely depositing a micro-alloy (Ti, Nb, V, Zr, etc.). In order to do so, it is necessary to re-solutionize the deposition of the coarse micro-alloy produced prior to the hot rolling step.
  • the heating temperature and its retaining time is preferably 1000°C or higher, and 600 seconds or longer, respectively, to perform the solutionization effect of the micro-alloy (Ti, Nb, V, Zr and the like) .
  • the heating temperature is 1400°C or higher and its retaining time is longer than 1000 seconds, the grain size of austenite becomes undesirably coarse.
  • the material steel sheet used in the present invention needs to have the grain size of the former austenite of 20 ⁇ m or smaller. This is from the perspective of improvement of elongation and stretch-flanging performance due to the micronization of the structure. That is, by subjecting a basis steel sheet having a grain size of the former austenite of 20 ⁇ m or smaller to the final annealing step and tempering step, the final structure becomes finer than in the case where the grain size is larger than 20 ⁇ m, and elongation and stretch-flanging performance are significantly improved.
  • This preliminary annealing is a treatment in which the above steel sheet is retained in a temperature range of Ac 3 point or higher for 5 seconds or longer, and is then cooled at an average cooling rate of 10°C/sec. or higher to a temperature of Ms point or lower or to the bainite transformation temperature range and retained.
  • the retaining temperature of the steel sheet is lower than Ac 3 point, a ferrite phase is likely to be produced, and a space factor of the low-temperature transformation phase of 90% or higher is not attained.
  • the retaining time is shorter than 5 seconds, transformation of the metal structure into austenite is insufficient, and a space factor of 90% or higher is not attained.
  • a material steel sheet is subjected to a heat treatment in which it is heated to and retained at a temperature range of (Ac 3 point -100°C) or higher but not higher than Ac 3 point for 1 second or longer but not longer than 2400 seconds, and is then cooled at a cooling rate of 10°C/sec or higher to Ms point or lower (cooling stop temperature).
  • a steel sheet having the structure (the space factor of ferrite: 5 to 30%, the space factor of martensite: 50 to 95%) mentioned above is obtained.
  • the mean crystal grain diameters of the ferrite phase and martensite in the high strength steel sheet which is finally obtained are determined by the sizes of the crystal grains of the ferrite phase and austenite produced when the material steel sheet is heated to and retained at a temperature range of (Ac 3 point -100°C) or higher but not higher than Ac 3 point. That is, in order to obtain a fine dual phase steel sheet in which the mean grain size of the ferrite phase is 3 ⁇ m or smaller and the mean grain size of martensite is 6 ⁇ m or smaller, it is necessary to heat the material steel sheet to a temperature range of (Ac 3 point -100°C) or higher but not higher than Ac 3 point and retain at the same.
  • the basis steel sheet has a Structure form mainly composed of a highly micronized lath-shaped low-temperature transformation phase due to the micronization effect of the micro-alloy.
  • a finely dispersed ferrite phase having a low space factor is produced.
  • the term "ferrite phase” used in this invention denotes annealed martensite or annealed bainite produced when martensite or bainite is annealed at a high temperature (dual-phase range).
  • the final structure obtained in the following hardening and tempering steps becomes a structure mainly composed of a very fine ferrite phase and martensite.
  • a temperature lower than (Ac 3 point -100°C) transformation into austenite does not proceed sufficiently, and the space factor of martensite after the heat treatment becomes lower than 50%, thereby lowering the stretch-flanging performance of the steel sheet.
  • the heating and retaining time in the final annealing needs to be in the range of 1 second or longer but not longer than 2400 seconds. It is preferably 5 seconds or longer but shorter than 1200 seconds.
  • the cooling rate after heating and retaining is 10°C/sec. or lower or the cooling stop temperature is higher than Ms point, generation of bainite, retained austenite phase and pearlite, generation of more ferrite phase than necessary, and deposition of a cementite phase are caused, and structures other than martensite are formed in large amounts. Therefore, the space factor of martensite is lowered, and the space factor and mean crystal grain size of the ferrite phase are excessively increased, leading to lowered elongation and stretch-flanging performance.
  • the higher the cooling rate at this time, and the lower the cooling stop temperature the higher the space factor of martensite is likely to be. However, since the temperature and time of the above dual-phase range annealing are suitably controlled, the space factor becomes no greater than 95%.
  • tempering reheating treatment
  • fine (ferrite phase +martensite) is formed in its metal structure.
  • martensite in an annealed state is very hard, which lowers elongation.
  • a difference in hardness between martensite and soft ferrite is large, which leads to lowered stretch-flanging performance.
  • the hardness of martensite needs to be reduced than in an annealed state, which is why it is subjected to the tempering step.
  • the retaining temperature in this tempering step is lower than 300°C, softening of martensite is insufficient, and therefore elongation and stretch-flanging performance of the steel sheet are lowered.
  • the retaining temperature is higher than 550°C, a coarse cementite phase is deposited, whereby the stretch-flanging performance of the steel sheet is lowered.
  • the retaining time of the tempering step is shorter than 60 seconds, softening of martensite is insufficient, and therefore elongation and stretch-flangingperformance of the steel sheet are lowered.
  • the retaining time is longer than 1200 seconds, martensite is too softened so that ensuring strength is made difficult, and the stretch-flanging performance of the steel sheet is lowered by the deposition of cementite.
  • This retaining time is preferably 90 seconds or longer but not longer than 900 seconds, and more preferably 120 seconds or longer but not longer than 600 seconds.
  • a steel sheet in which the space factors and grain sizes of the ferrite phase and martensite are suitably adjusted can be obtained, and a tensile strength as high as 590 MPa and excellent elongation and stretch-flanging performance are achieved.
  • Such a high strength steel sheet can be used as a steel sheet with excellent press formability as a material for various steel products typically including automobiles.
  • Tables 10 and 11 steel slabs having compositions of chemical constituents shown in Tables 10 and 11 below were prepared, and material steel sheets were prepared from the steel slabs under the hot rolling conditions and preliminary annealing conditions shown in Tables 12 and 13 below.
  • Tables 10 and 11 also show the Ac 3 point (Ac 3 transformation point) and martensite transformation start temperature, Ms point, for each steel type determined by equations (1) and (2).
  • [C], [Ni], [Sil], [v], [Mo], [W], [Mn], [Cr], [Cu], [P], [Al], [As], [Ti] and [Co] represent the amounts contained of C, Ni, Si, V, Mo, W, Mn, Cr, Cu, P, Al, As, Ti and Co (% by mass), respectively.
  • the material steel sheets obtained were subjected to the final annealing and reheating (tempering) under the conditions shown in Tables 14 and 15 below to prepare test steel sheets, and the structures (space factor of ferrite ⁇ , mean grain size of ferrite ⁇ , space factor of martensite M, and mean grain size of martensite M) and mechanical characteristics (tensile strength TS, elongation EL, hole expansion rate ⁇ ) of the test steel sheets were determined by the methods described below.
  • Tables 14 and 15 below also show the structures [phase constitution, space factor of low-temperature transformation phase, grain size of former austenite ( ⁇ )] of the test steel sheets before the final annealing.
  • the space factors of ferrite ⁇ and martensite M were determined by subjecting the structure pictures of the test steel sheets after being corroded with nital to image analysis.
  • the mean grain sizes of ferrite ⁇ and martensite M were measured by structure analysis using FE/SEM-EBSP, and the measurements were converted into "the equivalent of a circle diameter" described above to determine their mean value.
  • test pieces of No.1 to 3, 6, 9, 10, 13, 16 to 18 and 33 to 36 are not provided with satisfactory characteristics as the followings because at least one requirement of their composition of chemical constituents and manufacturing conditions falls outside the scope defined in the present invention.
  • the test piece of Experiment No.3 has low tensile strength TS since the amount of C contained does not fall with in the preferable range defined in the present invention.
  • the test piece of Experiment No. 6 has strength higher than necessary because the amount of C contained is higher than the preferable range defined in the present invention, so that ductility is lowered and elongation characteristics are deteriorated.
  • the amount of Si contained is higher than the preferable range defined in the present invention, and therefore its ductility is lowered, and elongation and stretch-flanging performance are deteriorated.
  • the amount of Mn contained does not fall with in the preferable range defined in the present invention, and therefore the space factor of ferrite is increased, deteriorating tensile strength and stretch-flanging performance.
  • the amount of Mn contained is higher than the preferable range defined in the present invention, and therefore its ductility is lowered, deteriorating elongation and stretch-flanging performance.
  • the heating temperature in the final annealing is much below the range defined in the present invention. Therefore, the space factor and mean grain size of ferrite, the space factor and mean grain size of martensite in the final structure fall outside the range defined in the present invention, and desired tensile strength and stretch-flanging performance have not been obtained.
  • the high strength steel sheet according to the present invention has excellent elongation and stretch-flanging performance at the same time, and thus has excellent press formability. Therefore, the high strength steel sheet according to the present invention can be processed by press molding to be used for various industrial products such as automobiles, especially for industrial products where weight reduction is necessary.

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  • Metallurgy (AREA)
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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Claims (2)

  1. Feuille d'acier à haute résistance qui comprend, en pour cent en masse, C : 0,05 à 0,3 % ; Si : 0,01 à 3 % ; Mn : 0,5 à 3,0 % ; Al : 0,01 à 0,1 % ; au moins un élément choisi parmi Ti, Nb, V et Zr dans une quantité de 0,01 à 1 % au total, et facultativement, Ni et/ou Cu dans une quantité de 1 % ou moins au total, Cr : 2 % ou moins, Mo : 1 % ou moins, B : 0,0001 à 0,005 %, Ca et/ou des métaux de terres rares dans une quantité de 0,003 % ou moins au total ; et le reste comprenant du fer et des impuretés inévitables, la feuille d'acier à haute résistance ayant un facteur d'espacement d'une phase de martensite, dans laquelle la structure qui est une partie principale de la structure métallique est la phase de martensite et une phase de ferrite ; le facteur d'espacement de la phase de martensite est de 70 à 95 % ; le facteur d'espacement de la phase de ferrite est de 5 à 25 % ; la somme totale de la phase de martensite et de la phase de ferrite est de 80 % ou plus, et la taille moyenne de grain de la phase de martensite est de 10 µm ou moins en termes de l'équivalent d'un diamètre de cercle, et dans laquelle la structure est admise comme le reste de la structure métallique contenant la bainite, la perlite et une phase d'austénite résiduelle ; et une résistance à la traction de 590 MPa ou plus.
  2. Procédé de fabrication d'une feuille d'acier à haute résistance selon la revendication 1, le procédé comprenant la fourniture d'un facteur d'espacement total de la phase de martensite et/ou de la phase de bainite dans la totalité de la structure métallique de 90 % ou plus ; l'utilisation d'une feuille d'acier ayant une taille de grain de l'austénite précédente de 20 µm ou moins en termes de l'équivalent d'un diamètre de cercle en tant que feuille d'acier de matériau ; le chauffage et le maintien de la feuille d'acier à une température de (point Ac3 -100 °C) ou plus mais non supérieure au pont Ac3 pendant 1 à 2400 secondes ; puis le refroidissement de la feuille d'acier à une température de démarrage de transformation de la martensite, point Ms, ou moins à une vitesse de refroidissement moyenne de 10 °C/s ou plus ; et ensuite la réalisation d'un traitement thermique dans lequel la feuille d'acier est chauffée et maintenue à une température de 300 à 550 °C pendant 60 à 1200 secondes.
EP11193464.2A 2006-07-14 2007-07-13 Feuilles d'acier très résistantes et leurs procédés de production Not-in-force EP2465961B1 (fr)

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JP2007144466A JP5201653B2 (ja) 2007-05-31 2007-05-31 伸びおよび伸びフランジ性に優れた高強度鋼板およびその製造方法
JP2007144705A JP4291860B2 (ja) 2006-07-14 2007-05-31 高強度鋼板およびその製造方法
JP2007145987A JP5234893B2 (ja) 2007-05-31 2007-05-31 伸びおよび伸びフランジ性に優れた高強度鋼板およびその製造方法
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Families Citing this family (50)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101126953B1 (ko) * 2007-11-22 2012-03-22 가부시키가이샤 고베 세이코쇼 고강도 냉연 강판
KR101230728B1 (ko) 2008-03-07 2013-02-07 가부시키가이샤 고베 세이코쇼 냉간 압연 강판
WO2010109702A1 (fr) * 2009-03-27 2010-09-30 株式会社神戸製鋼所 Tôle d'acier laminée à froid
JP4712838B2 (ja) * 2008-07-11 2011-06-29 株式会社神戸製鋼所 耐水素脆化特性および加工性に優れた高強度冷延鋼板
JP4712882B2 (ja) * 2008-07-11 2011-06-29 株式会社神戸製鋼所 耐水素脆化特性および加工性に優れた高強度冷延鋼板
JP5365112B2 (ja) * 2008-09-10 2013-12-11 Ｊｆｅスチール株式会社 高強度鋼板およびその製造方法
JP5418047B2 (ja) * 2008-09-10 2014-02-19 Ｊｆｅスチール株式会社 高強度鋼板およびその製造方法
JP5637342B2 (ja) * 2008-09-18 2014-12-10 国立大学法人 岡山大学 ホットプレス加工を施した鋼板部材及びその製造方法
KR101091306B1 (ko) * 2008-12-26 2011-12-07 주식회사 포스코 원자로 격납 용기용 고강도 강판 및 그 제조방법
JP5565785B2 (ja) 2009-03-05 2014-08-06 株式会社デルタツーリング 構造材
US8460800B2 (en) * 2009-03-31 2013-06-11 Kobe Steel, Ltd. High-strength cold-rolled steel sheet excellent in bending workability
CN102341518B (zh) * 2009-04-03 2013-04-10 株式会社神户制钢所 冷轧钢板及其制造方法
JP6010730B2 (ja) 2009-05-29 2016-10-19 日産自動車株式会社 高延性ダイクエンチによる高強度成形品及びその製造方法
DE102010003997A1 (de) * 2010-01-04 2011-07-07 Benteler Automobiltechnik GmbH, 33102 Verwendung einer Stahllegierung
JP5327106B2 (ja) * 2010-03-09 2013-10-30 Ｊｆｅスチール株式会社 プレス部材およびその製造方法
JP5671359B2 (ja) 2010-03-24 2015-02-18 株式会社神戸製鋼所 温間加工性に優れた高強度鋼板
JP5662902B2 (ja) 2010-11-18 2015-02-04 株式会社神戸製鋼所 成形性に優れた高強度鋼板、温間加工方法、および温間加工された自動車部品
KR101253885B1 (ko) * 2010-12-27 2013-04-16 주식회사 포스코 연성이 우수한 성형 부재용 강판, 성형 부재 및 그 제조방법
EP2489748B1 (fr) * 2011-02-18 2017-12-13 ThyssenKrupp Steel Europe AG Produit plat en acier laminé à chaud fabriqué à partir d'un acier à phase complexe et son procédé de fabrication
JP5667472B2 (ja) 2011-03-02 2015-02-12 株式会社神戸製鋼所 室温および温間での深絞り性に優れた高強度鋼板およびその温間加工方法
KR101604963B1 (ko) * 2011-03-31 2016-03-18 가부시키가이샤 고베 세이코쇼 가공성이 우수한 고강도 강판 및 그의 제조 방법
CN103597107B (zh) * 2011-06-10 2016-06-22 株式会社神户制钢所 热压成形品、其制造方法和热压成形用薄钢板
JP5636347B2 (ja) 2011-08-17 2014-12-03 株式会社神戸製鋼所 室温および温間での成形性に優れた高強度鋼板およびその温間成形方法
KR101598313B1 (ko) 2011-12-15 2016-02-26 가부시키가이샤 고베 세이코쇼 강도 및 연성의 편차가 작은 고강도 냉연 강판 및 그 제조 방법
US9115416B2 (en) * 2011-12-19 2015-08-25 Kobe Steel, Ltd. High-yield-ratio and high-strength steel sheet excellent in workability
DE102011057007B4 (de) * 2011-12-23 2013-09-26 Benteler Automobiltechnik Gmbh Verfahren zum Herstellen eines Kraftfahrzeugbauteils sowie Kraftfahrzeugbauteil
JP5860308B2 (ja) 2012-02-29 2016-02-16 株式会社神戸製鋼所 温間成形性に優れた高強度鋼板およびその製造方法
JP5632904B2 (ja) 2012-03-29 2014-11-26 株式会社神戸製鋼所 加工性に優れた高強度冷延鋼板の製造方法
JP5860343B2 (ja) 2012-05-29 2016-02-16 株式会社神戸製鋼所 強度および延性のばらつきの小さい高強度冷延鋼板およびその製造方法
US9708697B2 (en) 2012-05-31 2017-07-18 Kobe Steel, Ltd. High strength cold-rolled steel sheet and manufacturing method therefor
JP5906147B2 (ja) 2012-06-29 2016-04-20 株式会社神戸製鋼所 母材靭性およびｈａｚ靱性に優れた高張力鋼板
KR101223242B1 (ko) * 2012-06-29 2013-01-17 삼부기술 주식회사 지형정보 변화에 따른 영상 이미지의 공간영상 도화 시스템
JP5860354B2 (ja) 2012-07-12 2016-02-16 株式会社神戸製鋼所 降伏強度と成形性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法
KR101223245B1 (ko) * 2012-09-12 2013-01-17 삼부기술 주식회사 영상이미지의 기준점 대비 도화하기 위한 대상 지형지물을 촬영하는 공간 영상도화 시스템
JP5609945B2 (ja) 2012-10-18 2014-10-22 Ｊｆｅスチール株式会社 高強度冷延鋼板およびその製造方法
JP2015200012A (ja) * 2014-03-31 2015-11-12 株式会社神戸製鋼所 延性、伸びフランジ性、および溶接性に優れた高強度冷延鋼板、高強度溶融亜鉛めっき鋼板、および高強度合金化溶融亜鉛めっき鋼板
WO2015177582A1 (fr) * 2014-05-20 2015-11-26 Arcelormittal Investigación Y Desarrollo Sl Tôle d'acier doublement recuite à hautes caractéristiques mécaniques de résistance et ductilité, procédé de fabrication et utilisation de telles tôles
US10199910B2 (en) * 2014-10-03 2019-02-05 Ford Global Technologies, Llc Motor core formed from a single steel source and having separately processed rotor and stator laminations
JP6048620B1 (ja) * 2015-02-27 2016-12-21 Ｊｆｅスチール株式会社 高強度冷延鋼板およびその製造方法
EP3284841A4 (fr) * 2015-04-15 2018-12-19 Nippon Steel & Sumitomo Metal Corporation Tôle d'acier laminée à chaud et son procédé de fabrication
KR101725274B1 (ko) * 2015-10-16 2017-04-10 삼화스틸(주) 고강도 강판 및 그 제조방법
CN106119703B (zh) 2016-06-21 2018-01-30 宝山钢铁股份有限公司 一种980MPa级热轧双相钢及其制造方法
CN109642279B (zh) * 2016-08-05 2021-03-09 日本制铁株式会社 钢板及镀覆钢板
KR102206448B1 (ko) * 2016-08-10 2021-01-21 제이에프이 스틸 가부시키가이샤 박강판 및 그의 제조 방법
EP3473741B1 (fr) * 2016-08-30 2020-05-13 JFE Steel Corporation Tôle d'acier mince et procédé de production de cette dernière
KR101917472B1 (ko) * 2016-12-23 2018-11-09 주식회사 포스코 항복비가 낮고 균일연신율이 우수한 템퍼드 마르텐사이트 강 및 그 제조방법
KR102164074B1 (ko) * 2018-12-19 2020-10-13 주식회사 포스코 내마모성 및 고온 강도가 우수한 차량의 브레이크 디스크용 강재 및 그 제조방법
CN111363978B (zh) * 2018-12-26 2021-11-16 宝山钢铁股份有限公司 一种抗焊接软化的铁素体马氏体热轧双相钢及制造方法
JP2023506477A (ja) * 2019-12-13 2023-02-16 アルセロールミタル 熱処理された冷間圧延鋼板及びその製造方法
CN115369320B (zh) * 2022-08-10 2023-07-25 北京科技大学 一种海洋装备用高性能低密度薄板及其制备方法

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55122820A (en) 1979-03-13 1980-09-20 Kawasaki Steel Corp Manufacture of alloyed zinc-plated high tensile steel sheet with superior workability
JPS6043425A (ja) 1983-08-15 1985-03-08 Nippon Kokan Kk <Nkk> 熱延高強度高加工性複合組織鋼板の製造方法
US4854976A (en) * 1988-07-13 1989-08-08 China Steel Corporation Method of producing a multi-phase structured cold rolled high-tensile steel sheet
JPH05311244A (ja) * 1992-05-01 1993-11-22 Kobe Steel Ltd 伸びフランジ性の優れた高強度熱延原板合金化溶融亜鉛めっき鋼板の製造方法
EP1096029B1 (fr) * 1999-04-21 2006-01-25 JFE Steel Corporation Tole d'acier recouverte de zinc par immersion a chaud, a haute resistance ayant une excellente ductilite, et procede de production correspondant
JP3840864B2 (ja) * 1999-11-02 2006-11-01 Ｊｆｅスチール株式会社 高張力溶融亜鉛めっき鋼板およびその製造方法
JP3587116B2 (ja) * 2000-01-25 2004-11-10 Ｊｆｅスチール株式会社 高張力溶融亜鉛めっき鋼板およびその製造方法
JP3729108B2 (ja) 2000-09-12 2005-12-21 Ｊｆｅスチール株式会社 超高張力冷延鋼板およびその製造方法
US7090731B2 (en) * 2001-01-31 2006-08-15 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) High strength steel sheet having excellent formability and method for production thereof
EP1365037B1 (fr) * 2001-01-31 2008-04-02 Kabushiki Kaisha Kobe Seiko Sho Feuillard en acier a haute resistance ayant une excellente formabilite, et son procede de production
FR2830260B1 (fr) * 2001-10-03 2007-02-23 Kobe Steel Ltd Tole d'acier a double phase a excellente formabilite de bords par etirage et procede de fabrication de celle-ci
JP4306202B2 (ja) * 2002-08-02 2009-07-29 住友金属工業株式会社 高張力冷延鋼板及びその製造方法
JP4062616B2 (ja) * 2002-08-12 2008-03-19 株式会社神戸製鋼所 伸びフランジ性に優れた高強度鋼板
JP4085826B2 (ja) * 2003-01-30 2008-05-14 Ｊｆｅスチール株式会社 伸びおよび伸びフランジ性に優れた二相型高張力鋼板およびその製造方法
JP4457681B2 (ja) * 2004-01-30 2010-04-28 Ｊｆｅスチール株式会社 高加工性超高強度冷延鋼板およびその製造方法
JP4396347B2 (ja) 2004-03-25 2010-01-13 Ｊｆｅスチール株式会社 延性および伸びフランジ性に優れる高張力鋼板の製造方法
JP2005336526A (ja) * 2004-05-25 2005-12-08 Kobe Steel Ltd 加工性に優れた高強度鋼板及びその製造方法
JP4445365B2 (ja) * 2004-10-06 2010-04-07 新日本製鐵株式会社 伸びと穴拡げ性に優れた高強度薄鋼板の製造方法
CA2531616A1 (fr) * 2004-12-28 2006-06-28 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Tole mince d'acier a haute resistance mecanique possedant une resistance elevee a la fragilisation par l'hydrogene et une grande aptitude a l'usinage
JP2006194056A (ja) 2005-01-11 2006-07-27 Hisashi Kawajiri 網戸の網の均一な張りを得るための網張りローラー用特殊具
JP4714010B2 (ja) 2005-11-25 2011-06-29 トッパン・フォームズ株式会社 ラベル製造装置
JP2007145987A (ja) 2005-11-28 2007-06-14 Kaneka Corp 環状オレフィンコポリマー樹脂押出発泡体およびその製造方法
JP4561614B2 (ja) 2005-11-29 2010-10-13 Ｊｆｅスチール株式会社 圧延材の保持装置

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EP2053140A4 (fr) 2011-06-29
EP2465961A1 (fr) 2012-06-20
US20090277547A1 (en) 2009-11-12
EP2465962A1 (fr) 2012-06-20
EP2465962B1 (fr) 2013-12-04
WO2008007785A1 (fr) 2008-01-17
KR101082680B1 (ko) 2011-11-15
EP2053140A1 (fr) 2009-04-29
CN101460647B (zh) 2015-05-20
CN101460647A (zh) 2009-06-17
EP2053140B1 (fr) 2013-12-04

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