EP3245310A2 - Acier à deux phases à propriétés améliorées - Google Patents

Acier à deux phases à propriétés améliorées

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Publication number
EP3245310A2
EP3245310A2 EP16706031.8A EP16706031A EP3245310A2 EP 3245310 A2 EP3245310 A2 EP 3245310A2 EP 16706031 A EP16706031 A EP 16706031A EP 3245310 A2 EP3245310 A2 EP 3245310A2
Authority
EP
European Patent Office
Prior art keywords
steel sheet
temperature
manganese
carbon
molybdenum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP16706031.8A
Other languages
German (de)
English (en)
Inventor
Grant Aaron THOMAS
Jose Mauro BARROS LOSZ
Luis Gonzalo GARZA-MARTINEZ
Eddie Ray CASE
Eric Petersen
Prabhat Rastogi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cleveland Cliffs Steel Properties Inc
Original Assignee
AK Steel Properties Inc
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 AK Steel Properties Inc filed Critical AK Steel Properties Inc
Publication of EP3245310A2 publication Critical patent/EP3245310A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for drawing, e.g. for deep-drawing
    • C21D8/0478—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for drawing, e.g. for deep-drawing involving a particular surface treatment
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • 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
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • 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
    • C23C2/26—After-treatment
    • 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
    • C21D2211/002—Bainite
    • 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 steel compositions and processing methods for production of steel using thermal processing techniques such that the resulting steel exhibits high strength and/or cold formability.
  • the present steel is produced using a composition and a modified thermal process that together produces a resulting micro structure consisting of generally ferrite and a second phase generally comprising martensite and bainite (among other constituents).
  • the composition includes certain alloying additions and the thermal process includes a hot-dip
  • HDG galvanizing/galvannealing
  • FIGURE 1 depicts a schematic view of a HDG temperature profile with a
  • quenching step performed prior to galvanizing/galvannealing.
  • FIGURE 2 depicts the HDG temperature profile of FIGURE 1, with the average cooling rate of the HDG temperature profile shown in phantom.
  • FIGURE 3 depicts a schematic view of an alternative HDG temperature profile with a quenching step performed after galvanizing/galvannealing.
  • FIG. 1 shows a schematic representation of a combination of a typical hot-dip galvanizing thermal profile and a modified hot-dip galvanizing thermal profile.
  • the modified thermal cycle is used to achieve high strength and good formability in a dual phase steel sheet (described in greater detail below).
  • the steel sheet generally comprises two phases after the thermal cycles - a first phase of predominantly ferrite and a second phase.
  • first phase of predominantly ferrite
  • second phase is generally used to refer to a phase generally comprising predominately martensite with some bainite.
  • such a second phase may also include any one or more of cementite and/or residual austenite.
  • FIG. 1 is shown in connection with hot-dip galvanizing, in other embodiments a galvannealing or other hot-dip coating process can be used. In still other embodiments, hot-dip coating processes are omitted entirely and the steel sheet is merely subjected to the thermal profile as shown.
  • the solid line in FIG. 1 shows a schematic view of the typical hot-dip galvanizing or galvannealing thermal profile (10).
  • the typical thermal profile (10) involves heating the steel sheet to a peak metal temperature (12) and optionally holding the steel sheet at the peak metal temperature (12) for a first predetermined period of time.
  • the peak metal temperature (12) is at least above the austenite transformation temperature (AO (e.g., dual phase austenite + ferrite region).
  • AO austenite transformation temperature
  • the peak metal temperature may also include temperatures above the temperature at which ferrite completely transforms to austenite (A 3 ) (e.g., the single phase, austenite region).
  • a 3 austenite
  • the steel sheet is held at the peak metal temperature (12) for a first predetermined amount of time. It should be understood that the particular amount of time that the steel sheet is held at the peak metal temperature (12) may be varied by a number of factors such as the particular chemistry of the steel sheet, or the desired volumetric quantity of the second phase in the steel sheet at the conclusion of the thermal cycle.
  • the time held at the peak metal temperature (12) may be reduced to zero or near zero.
  • the peak metal temperature can be increased to compensate for such a reduction.
  • the profile (10) involves rapidly cooling the steel sheet to an intermediate temperature (14).
  • the steel sheet is then held at the intermediate temperature (14) for a second predetermined period of time.
  • the steel sheet is held at the intermediate temperature (14) for a sufficient amount of time to permit the steel sheet to reach a temperature that is near the temperature of the zinc bath.
  • the steel sheet is next inserted into a liquid zinc galvanizing tub or galvannealing apparatus.
  • the temperature of the steel sheet is slightly reduced to a bath temperature (16) that is below the intermediate temperature (14).
  • the bath temperature (16) is generally below the intermediate temperature (14) to avoid dross formation upon entry of the steel sheet into the liquid zinc.
  • the steel sheet remains at the bath temperature (16) for the duration of the
  • the steel sheet is removed from the bath at some period of time and then elevated to an annealing temperature.
  • the particular temperature of the bath temperature (16) is at least above the melting point of zinc (e.g., 419° C, 787° F).
  • the bath temperature (16) may be even higher depending on the particular configuration of the galvanizing bath or galvannealing apparatus.
  • the intermediate temperature (14) may remain the same as shown, be correspondingly raised, or even lowered.
  • the steel sheet is cooled below the martensite start temperature (M s ), thereby transforming at least some austenite into martensite.
  • M s martensite start temperature
  • other constituents may form such as bainite, pearlite, or retained austenite.
  • the second phase may contain one or more of martensite, bainite, pearlite and/or retained austenite, it should be understood that the second phase is generally characterized by formation of predominately martensite.
  • the average cooling rate from the peak metal temperature (12) to the martensite start temperature (M s ) may be insufficient to form a desirable volumetric quantity of martensite - instead forming non- martensitic transformation products (e.g., bainite, cementite, pearlite, and/or etc.). This may be the case regardless of how quickly the steel sheet is cooled after galvanizing or galvannealing.
  • conventional dual phase steels used in such a process often includes high alloy content to increase hardenability and thereby avoid formation of non- martensitic transformation products.
  • the typical thermal profile (10) described above can be any thermal profile (10) described above.
  • this alternative procedure is generally identical to the procedure described above with the exception of the portion of the procedure related to the intermediate temperature (14).
  • the steel sheet is quenched from the peak metal temperature (12) to a quench temperature (20).
  • the cooling rate from the peak metal temperature (12) to the quench temperature (20) is generally high enough to transform at least some of the austenite formed at the peak metal temperature (12) to martensite.
  • the cooling rate is rapid enough to transform austenite to martensite instead of other non-martensitic transformation products such as ferrite, pearlite, or bainite which form at relatively lower cooling rates.
  • the quench temperature is below the martensite start temperature (M s ).
  • the difference between the quench temperature (20) and the martensite start temperature (M s ) can vary depending on the individual composition of the steel sheet being used. However, in many embodiments the difference between quench temperature (20) and M s is sufficiently great to form a predominately martensitic second phase.
  • the temperature of the steel sheet is maintained at the quench temperature for a predetermined quench time. Because formation of martensite is nearly instantaneous, the particular amount of time during which the steel sheet is at the quench temperature is generally insignificant.
  • the steel sheet is reheated to the intermediate temperature (14) or to another temperature at or near the bath temperature (16). In the present example, reheating is relatively quick and may be performed using various methods such as induction heating, torch heating, and/or other methods known in the art. Once reheated, the steel sheet is inserted into a zinc bath.
  • the steel sheet In the zinc bath, the steel sheet will reach the bath temperature (16), as described above, where the steel sheet will remain for the remainder of the galvanizing.
  • the particular amount of time during which the steel sheet is in the zinc bath is largely determined by the galvanizing/galvannealing process.
  • the martensite is tempered to thereby improve the mechanical properties of the steel sheet.
  • the steel sheet may be heated to an annealing temperature after removal from the bath.
  • the reheating step is described herein as being in connection with a coating step, such as galvanizing or galvannealing, it should be understood that no such limitation is intended.
  • the reheating step may merely be performed and then the process may proceed as described below.
  • the steel sheet is held at the intermediate temperature (14) or the bath temperature (16) despite not actually being subjected to a galvanizing or galvannealing treatment.
  • the steel sheet may be held at a lower temperature (e.g., 400° C) relative to the bath temperature (16) because heating the steel sheet to the melting point of zinc is not necessary without application of zinc.
  • the steel sheet may be held at such a temperature for any suitable time as will be apparent to those of ordinary skill in the art in view of the teachings herein.
  • the steel sheet is cooled to room temperature, as similarly described above. Accordingly, in the present example, the steel sheet is first heated to a peak metal temperature (12) to form austenite and optionally ferrite. Next the steel sheet is cooled from the peak metal temperature (12) to the quench temperature (20) to form martensite or other constituents of the second phase. After quenching, the steel sheet is reheated to approximately the zinc bath temperature for galvanizing and optionally galvannealing. Finally, the steel sheet is cooled to ambient temperature.
  • FIG. 2 shows a comparison of the average cooling rate (30) of the typical thermal profile (10) versus the average cooling rate (32) of the typical thermal profile (10) modified to include the quench step (18).
  • the quench step (18) substantially reduces the average cooling rate of the typical thermal profile (10).
  • average cooling rate may depend at least partially on the feed speed of the galvanizing/galvannealing line. For instance, where feed speeds of about 30 meters per minute are used, the average cooling rate using the typical thermal profile (10) is about 17° C per second, while the average cooling rate using the modifications described herein is about 48° C per second.
  • the average cooling rate using the typical thermal profile (10) is about 6° C per second, while the average cooling rate using the modifications described herein is about 16° C per second. In yet other examples where feed speeds of about 120 meters per minute are used, the average cooling rate using the typical thermal profile (10) is about 4° C per second, while the average cooling rate using the modifications described herein is about 12° C per second.
  • the quench step (18) may be performed after galvanizing/galvannealing instead of before.
  • the quench step (18) may be performed as similarly described above with a rapid cooling of the steel sheet below the martensite start temperature (M s ).
  • M s martensite start temperature
  • the average cooling rate from the peak metal temperature (12) to the intermediate temperature (14) or bath temperature (16) is similar to the average cooling rate (30) for the typical thermal profile (10) shown in FIG. 2.
  • a tempering step (40) may also be performed, where the steel sheet is heated to a predetermined temperature above or below the martensite start temperature (M s ) for a predetermined period of time after the quench step (18).
  • M s martensite start temperature
  • the average cooling rate is also similar to the average cooling rate (30) for the typical thermal profile (10) shown in FIG. 2.
  • HER hole expansion ratio
  • the steel sheet may include various alloying elements typically present in
  • carbon provides increased strength.
  • increasing carbon concentration generally lowers the M s temperature, lowers transformation temperatures for other non-martensitic constituents (e.g., bainite, ferrite, pearlite), and increases the time required for non-martensitic products to form.
  • increased carbon concentrations may improve the hardenability of the material thus retaining formation of non-martensitic constituents near the core of the material where cooling rates may be locally depressed.
  • carbon additions may be limited as significant carbon concentrations can lead to detrimental effects on weldability.
  • carbon can have a detrimental effect of formability. Therefore, the carbon content is generally kept around 0.067- 0.14% by weight.
  • manganese provides increased strength by lowering
  • Manganese can further improve the propensity of the steel sheet to form martensite by increasing hardenability. Manganese can also increase strength through solid solution strengthening. However, the presence of manganese in large concentrations can degrade formability. Therefore the manganese content is generally present in the concentration of about 1.65-2.9% by weight.
  • aluminum is generally present in the concentration of about 0.015-0.07% by weight.
  • silicon can be added to promote a dual phase structure consisting of predominately ferrite and martensite.
  • silicon is generally present in the concentration of about 0.1-0.25% by weight.
  • niobium is added to refine ferrite grains. Such grain
  • refinement is desirable to improve formability and improve weld quality.
  • niobium is generally present in the concentration of about 0-0.045% by weight. Alternatively, in some examples niobium is present in the concentration of about 0.015-0.045% by weight.
  • vanadium is added to increase hardenability and/or refine ferrite grains.
  • vanadium is generally included in a concentration less than or equal to 0.05% by weight.
  • chromium is added to improve formability and weld quality.
  • chromium may be included in the concentration of about 0-0.67%, or 0.2-0.67% by weight.
  • molybdenum may be used to increase hardenability.
  • molybdenum can be included in a concentration of about 0.08-0.45% by weight. In other embodiments the lower limit concentration of molybdenum is reduced further, or even eliminated entirely.
  • titanium and boron are added to increase strength. It should be understood that in some embodiments titanium and boron may be used together, separately in lieu of the other, or neither element may be used. When titanium is used, titanium is present in the concentration of about 0.01-0.03% by weight. When boron is used, boron is present in the concentration of about 0.0007-0.0013% by weight.
  • titanium is added together.
  • titanium may be included to combine with nitrogen prior to the nitrogen combining with boron.
  • titanium is included in concentrations of about 3.43 times the weight percent of nitrogen. When included in this concentration, titanium generally combines with nitrogen, thereby preventing boron from forming nitrides.
  • Embodiments of the steel sheet made with the compositions set forth above in Table 1 were subjected to mechanical testing. Mechanical properties for a selected number of the compositions set forth in Table 1 are set forth below in Table 2.
  • Embodiments of the steel sheet were made with the compositions set forth in Table 3 below.
  • the particular compositions shown in Table 3 are based on the compositional ranges set forth in Table 1.
  • Embodiments of the steel sheet made with the compositions set forth above in Table 3 were subjected to mechanical testing. Mechanical properties for each of the compositions set forth in Table 3 are set forth below in Tables 4 through 15.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Coating With Molten Metal (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Abstract

Cette invention concerne un procédé de traitement d'une tôle d'acier à deux phases. Ledit procédé consiste à chauffer la tôle d'acier à une première température (Tl), refroidir la tôle d'acier à une seconde température (T2), faire passer la tôle d'acier à une troisième température (T3), et refroidir la tôle d'acier à la température ambiante. La température Tl est au moins supérieure à la température de transformation austénitique et ferritique de la tôle d'acier. La température T2 est supérieure à la température de début de transformation martensitique (Ms) La vitesse de refroidissement à la température T2 est suffisamment rapide pour transformer au moins une partie de l'austénite en martensite.
EP16706031.8A 2015-01-14 2016-01-14 Acier à deux phases à propriétés améliorées Withdrawn EP3245310A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201562103286P 2015-01-14 2015-01-14
PCT/US2016/013338 WO2016115303A2 (fr) 2015-01-14 2016-01-14 Acier à deux phases à propriétés améliorées

Publications (1)

Publication Number Publication Date
EP3245310A2 true EP3245310A2 (fr) 2017-11-22

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Family Applications (1)

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Country Status (15)

Country Link
US (1) US20160201159A1 (fr)
EP (1) EP3245310A2 (fr)
JP (1) JP2018508653A (fr)
KR (2) KR20200003264A (fr)
CN (2) CN110218942A (fr)
AU (1) AU2016206736B2 (fr)
BR (1) BR112017014686A2 (fr)
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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI628310B (zh) * 2017-08-08 2018-07-01 中國鋼鐵股份有限公司 High-strength lubricating galvanized steel sheet and manufacturing method thereof
EP4569150A1 (fr) * 2022-08-12 2025-06-18 ArcelorMittal Acier martensitique laminé à froid et son procédé de production

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56146853A (en) * 1980-04-11 1981-11-14 Nippon Steel Corp Dual-phase steel plate for car with superior weldability and high corrosion resistance
JP2761096B2 (ja) * 1990-11-05 1998-06-04 株式会社神戸製鋼所 高延性高強度合金化溶融亜鉛めっき鋼板の製造方法
JPH0693340A (ja) * 1992-09-14 1994-04-05 Kobe Steel Ltd 伸びフランジ性の優れた高強度合金化溶融亜鉛めっき鋼板の製造方法及び製造設備
JP3126911B2 (ja) * 1995-12-27 2001-01-22 川崎製鉄株式会社 めっき密着性の良好な高強度溶融亜鉛めっき鋼板
CN100471982C (zh) * 2002-11-26 2009-03-25 Uec科技有限责任公司 制造双相钢板的方法
JP4171454B2 (ja) * 2004-11-19 2008-10-22 新日本製鐵株式会社 伸びおよび穴拡げ性に優れた高強度鋼板または溶融亜鉛めっき高強度鋼板の製造設備
JP4681290B2 (ja) * 2004-12-03 2011-05-11 本田技研工業株式会社 高強度鋼板及びその製造方法
US11155902B2 (en) * 2006-09-27 2021-10-26 Nucor Corporation High strength, hot dip coated, dual phase, steel sheet and method of manufacturing same
ES2367713T3 (es) * 2007-08-15 2011-11-07 Thyssenkrupp Steel Europe Ag Acero de fase dual, producto plano de un acero de fase dual tal y procedimiento para la fabricación de un producto plano.
PL2028282T3 (pl) * 2007-08-15 2012-11-30 Thyssenkrupp Steel Europe Ag Stal dwufazowa, płaski wyrób wytworzony ze stali dwufazowej i sposób wytwarzania płaskiego wyrobu
EP2123786A1 (fr) * 2008-05-21 2009-11-25 ArcelorMittal France Procédé de fabrication de tôles d'aciers dual phase laminées à froid à trés haute résistance et tôles ainsi produites
JP5304522B2 (ja) * 2009-08-03 2013-10-02 新日鐵住金株式会社 加工性に優れた高強度鋼板及びその製造方法
KR100958019B1 (ko) * 2009-08-31 2010-05-17 현대하이스코 주식회사 복합조직강판 및 이를 제조하는 방법
CN102021482B (zh) * 2009-09-18 2013-06-19 宝山钢铁股份有限公司 一种冷轧热镀锌双相钢及其制造方法
KR20170104159A (ko) * 2013-05-17 2017-09-14 에이케이 스틸 프로퍼티즈 인코포레이티드 양호한 연성을 나타내는 고강도 스틸 그리고 용융 아연 욕 하류의 인-라인 열처리를 통한 생산 방법

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PH12017501293A1 (en) 2018-01-29
BR112017014686A2 (pt) 2018-01-09
UA119189C2 (uk) 2019-05-10
CA2972470C (fr) 2019-10-22
KR20170095363A (ko) 2017-08-22
RU2017123566A (ru) 2019-02-14
TW201812053A (zh) 2018-04-01
JP2018508653A (ja) 2018-03-29
CO2017006995A2 (es) 2017-09-20
CN110218942A (zh) 2019-09-10
CN107109586A (zh) 2017-08-29
RU2017123566A3 (fr) 2019-02-14
AU2016206736B2 (en) 2019-02-14
WO2016115303A3 (fr) 2016-09-09
AU2016206736A1 (en) 2017-07-13
US20160201159A1 (en) 2016-07-14
TWI653342B (zh) 2019-03-11
TW201641715A (zh) 2016-12-01
MX2017009192A (es) 2018-04-30
WO2016115303A2 (fr) 2016-07-21
CA2972470A1 (fr) 2016-07-21
KR20200003264A (ko) 2020-01-08

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