EP3688203B1 - Produit d'acier plat et son procédé de fabrication - Google Patents

Produit d'acier plat et son procédé de fabrication Download PDF

Info

Publication number
EP3688203B1
EP3688203B1 EP17780063.8A EP17780063A EP3688203B1 EP 3688203 B1 EP3688203 B1 EP 3688203B1 EP 17780063 A EP17780063 A EP 17780063A EP 3688203 B1 EP3688203 B1 EP 3688203B1
Authority
EP
European Patent Office
Prior art keywords
flat steel
steel product
martensite
temperature
cooling
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.)
Active
Application number
EP17780063.8A
Other languages
German (de)
English (en)
Other versions
EP3688203A1 (fr
Inventor
Richard Georg THIESSEN
Manuela Irnich
Bernd Linke
Jan-hendrik RUDOLPH
Rainer FECHTE-HEINEN
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.)
ThyssenKrupp Steel Europe AG
ThyssenKrupp AG
Original Assignee
ThyssenKrupp Steel Europe AG
ThyssenKrupp 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 Europe AG, ThyssenKrupp AG filed Critical ThyssenKrupp Steel Europe AG
Priority to PL17780063.8T priority Critical patent/PL3688203T3/pl
Priority to EP22159990.5A priority patent/EP4043603A1/fr
Publication of EP3688203A1 publication Critical patent/EP3688203A1/fr
Application granted granted Critical
Publication of EP3688203B1 publication Critical patent/EP3688203B1/fr
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • 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
    • C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
    • C21D1/22—Martempering
    • 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
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • 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
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat 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
    • 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
    • C22C38/001—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
    • C22C38/002—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
    • C22C38/02—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
    • 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
    • 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
    • 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
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • C23C2/29—Cooling or quenching
    • 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
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/34—Pretreatment of metallic surfaces to be electroplated
    • C25D5/36—Pretreatment of metallic surfaces to be electroplated of iron or steel
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/06—Wires; Strips; Foils
    • C25D7/0614—Strips or foils
    • 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
    • C21D2211/001—Austenite
    • 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
    • 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 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
    • C21D8/0436—Cold rolling
    • 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
    • C21D8/0447—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 heat 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
    • 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
    • C21D9/48—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals deep-drawing sheets

Definitions

  • the invention relates to a high-strength flat steel product suitable for bake-hardening treatment and a method for producing such a flat steel product.
  • BH steel flats suitable for bake hardening (BH) treatment are also referred to as bake hardening (BH) steel flats and are commonly used in automotive applications such as body panels.
  • BH steel flat products have a lower strength level before BH treatment than after BH treatment. This circumstance is used to carry out the forming of flat steel products to be formed before the BH treatment and thus with lower yield points and better forming capacity.
  • the strength level is increased by the BH treatment, in which the material is subjected to heat treatment.
  • the BH treatment is typically performed for 3 to 40 minutes within a temperature range of 120 to 250°C.
  • the BH treatment stimulates atoms of interstitially dissolved elements to diffuse, whereby they can attach to dislocations. This hinders the dislocations in their movement, which leads to an increase in the yield point.
  • This effect of the increase in yield point is also referred to as the bake hardening effect (BH effect) and the difference in the yield points before and after the BH treatment is also referred to as the bake hardening value (BH value).
  • BH effect bake hardening effect
  • BH value bake hardening value
  • yield point in the present case means the characteristic value referred to as the upper yield point ReH.
  • the increase in yield point or the BH value is discussed here, for steel flat products that do not have a pronounced yield point before the BH treatment but have a yield point, this means the difference between the yield point RpO,2 before the BH treatment and the yield point ReH understood after BH treatment.
  • a high BH value has a positive effect on the buckling resistance of components made from BH flat steel products. As a result, it is possible to reduce the thickness of the component by using flat steel products, which have a high BH value, while maintaining the rigidity of the components.
  • the BH effect has so far been used for soft steels, which often have a predominantly ferritic matrix, only low martensite content and tensile strengths below 700 MPa.
  • the sheets should consist of a steel which, in addition to iron and unavoidable impurities, contains 0.0010 - 0.0040% by mass C, 0.005 - 0.05% by mass Si, 0.1 - 0.8% by mass Mn, 0.
  • the value of the quotient of the proportions of Mn and P [Mn%]/[P%] should be between 1.6 and 45, and the amount present in solid solution Carbon, which is obtained from [C%]-(12/93)x[Nb%], should be between 0.0005 and 0.0025% by mass.
  • the cold-rolled sheets suitable for bake-hardening should satisfy the equation X(222)/ ⁇ X(119)+X(200) ⁇ 3.0.
  • X(222), X(110) and X(200) are the integrated X-ray diffraction intensity of the ⁇ 222 ⁇ plane, the ⁇ 110 ⁇ plane and the ⁇ 200 ⁇ plane which are parallel to a plane which starting from the sheet surface is 1 ⁇ 4 of the sheet thickness.
  • the sheets should have good deep-drawing properties and tensile strengths of 300 to 450 MPa.
  • High-strength flat steel products are usually used for body parts in order to be able to realize small component thicknesses with good dent resistance.
  • High-strength steels are characterized by a high proportion of martensite in the structure. Martensite is a carbon-rich structural component from which carbon can diffuse into other structural components when thermally activated. The higher the proportion of martensite in the structure, the more pronounced the BH effect is typically. However, high proportions of martensite go hand in hand with poor deformability.
  • the sheets should contain 0.05 - 0.30% by mass C, 0.5 - 3.0% by mass Si, 0.2 - 3.0% by mass Mn, up to 0.10% by mass P, up to 0.010% by mass S, up to 0.010% by mass N and 0.001 - 0.10% by mass Al, the rest iron and unavoidable impurities.
  • the structure should contain 50 - 85% by area martensite, less than 5% by area ferrite and the rest bainite and have a dislocation density of at least 5.0 x 10 15 m -2 and at least 0.08% by mass of dissolved carbon.
  • the sheets should be suitable for bake-hardening and have good bending properties and tensile strengths of 1180 MPa or more.
  • the sheets are produced using conventional continuous casting, hot rolling and cold rolling.
  • the cold-rolled sheets are to be heated to annealing temperatures of Ac3+50°C up to 930 °C, held at this annealing temperature for 30 to 1200 s, then at an average speed of 15 °C/s or more to a cooling stop temperature between 450 °C C to 550 °C, then immersed in a molten bath for 10 to 60 s at 480 to 525 °C within a maximum of 30 s from reaching the cooling stop temperature and then to 200 ° at an average cooling rate of 15 °C/s or more C to be cooled.
  • the JP 2014 034716 describes a high-strength steel flat product with a tensile strength of 980 MPa or more, good ductility and good hole expansion properties, and a method for its production.
  • the steel flat product has a microstructure containing less than 80 area % martensite, of which less than 75 area % is tempered martensite.
  • the WO 2016/177763 A1 describes a steel flat product with an optimized combination of strength and elongation and a method for its production.
  • the retained austenite content in the structure of the steel flat product should be less than 2% by volume in order to improve the isotropy of the deformability.
  • the JP 2015 224359 A describes a high-strength steel flat product with good processing properties and a tensile strength of 980 MPa and more, as well as a process for its production.
  • the reheating (partitioning) that takes place after quenching to coolant temperature takes place in very short times of well under 10 s in order to provide an efficient and cost-effective process.
  • a low-temperature transformation structure is thereby obtained, which comprises tempered martensite, bainite and tempered bainite.
  • the object of the invention was to specify a high-strength flat steel product with optimized properties, in particular very good bake-hardening properties and very good forming properties both before and after a BH treatment.
  • the object was achieved in that at least the method steps specified in claim 10 are completed during the production of a flat steel product according to the invention.
  • a flat steel product according to the invention is characterized in that, before a BH treatment, it has a yield point Rp0.2 of over 700 MPa or a yield point ReH of over 700 MPa, a tensile strength Rm of 950-1500 MPa and an elongation A80 of 7-25% and has a high bake hardening (BH) potential.
  • the BH potential is expressed in the flat steel product having an increase in yield point of at least 80 MPa after a BH treatment and an elongation A80_BH which is at least half as high as the elongation A80 before the BH treatment.
  • the carbon content of the steel of a flat steel product according to the invention is 0.1-0.5% by weight.
  • carbon contributes to the formation and stabilization of austenite.
  • C contents of at least 0.1 wt. %, preferably at least 0.12 wt is to ensure a residual austenite content of at least 5% by volume on the flat steel product according to the invention.
  • the residual austenite can be stabilized particularly reliably if the C content is at least 0.14% by weight.
  • the C content has a strong influence on the strength of the martensite. This applies to both the strength of the martensite formed during the first quench and the strength of the martensite formed during the second quench that begins after the partitioning anneal.
  • the C content should be at least 0.1% by weight.
  • a minimum content of 0.1% by weight is required in order to provide sufficient carbon atoms for diffusion to the dislocations present in the material during a later BH treatment and thus to ensure a pronounced BH effect.
  • Particularly high BH values are obtained when the C content is at least 0.14% by weight.
  • the martensite start temperature Ms also becomes lower temperatures shifted.
  • a C content above 0.5% by weight could therefore lead to insufficient martensite formation during quenching.
  • the workability, in particular the weldability is also impaired at higher C contents, which is why the C content should be at most 0.5% by weight, preferably at most 0.4% by weight.
  • the Mn content of the steel of a flat steel product according to the invention is therefore at least 1.0% by weight, preferably at least 1.9% by weight, in order to provide a pearlite-free structure for the further process steps after the first quenching.
  • the Mn content increases, the weldability deteriorates and the risk of severe segregation occurring increases. Segregations are chemical inhomogeneities in the composition formed during the solidification process in the form of macroscopic or microscopic demixing.
  • the Mn content of the steel of a flat steel product according to the invention is limited to a maximum of 3.0% by weight, preferably a maximum of 2.7% by weight.
  • the Si content of the steel of a flat steel product according to the invention is limited to 0.9-2.0% by weight.
  • Si as an alloying element helps to suppress cementite formation.
  • Cementite is an iron carbide.
  • the formation of cementite binds carbon in the form of iron carbide and is no longer available in atomic form for solution in the iron lattice.
  • atomic carbon which is interstitially dissolved in the iron lattice, contributes significantly to the stabilization of retained austenite on the one hand and to the improvement of the BH effect on the other.
  • retained austenite helps improve formability, especially elongation, both before and after BH treatment.
  • a similar effect in terms of stabilizing the retained austenite can also be achieved by alloying aluminum.
  • the minimum Si content required to obtain a flat steel product according to the invention can be reduced to 0.5% by weight.
  • the Si content should be at least 0.9% by weight.
  • the steel should contain no more than 2.0% by weight, preferably no more than 1.6% by weight.
  • Aluminum is present in the steel of a flat steel product according to the invention in contents of 0.02-1.5% by weight.
  • Al is added for deoxidation and grain refinement. Grain refinement occurs through the formation of AlN clusters and AlN precipitates, each of which inhibits grain growth during austenitizing annealing, which is also referred to as austenitizing for short.
  • AlN clusters are generally understood to mean accumulations of aluminum and nitrogen atoms which, in contrast to AlN precipitations, do not have a sharp phase boundary to the matrix.
  • the Al content should be at least 0.01% by weight. Particularly fine austenite grains can thus be set by the addition of Al and N to lattice defects and their subsequent cluster formation or precipitation.
  • the finer austenite grain size results in fine martensite with a small lancet length being formed during the first quench.
  • increased Al contents of at least 0.02% by weight are particularly advantageous.
  • a further advantage for the formation of AlN clusters and AlN precipitations is a high number of lattice defects that are available during heating to the austenitizing temperature (THZ). These lattice defects can be introduced into the material before austenitizing, for example in the form of dislocations.
  • THZ austenitizing temperature
  • Aluminum, like silicon, contributes to the suppression of cementite formation.
  • Al is not as effective as Si in suppressing cementite formation.
  • Si has a negative effect on scaling and coatability and thus on the surface quality of the steel flat products
  • Al can be used as a substitute for Si when selecting the alloy composition.
  • Al contents of at least 0.1% by weight have proven to be particularly effective for the steel composition according to the invention proven. At lower Al contents, the influence of Al on cementite suppression is not significant.
  • aluminum contributes to increasing the carbon activity in martensite. This applies both to the martensite formed after the first quench, which takes place after austenitizing, and to the martensite formed after the second quench, which takes place after partitioning annealing.
  • the increase in carbon activity also shows a positive effect on the BH effect.
  • high carbon activity also increases the driving force for attachment of carbon atoms to dislocations, resulting in the increase in BH value.
  • Al contents of at least 0.02% by weight have proven to be particularly advantageous for increasing the carbon activity in the martensite. Since aluminum increases the annealing temperature required for complete austenitization and complete austenitization is only possible with difficulty at Al contents above 1.5% by weight, the Al content of the steel of the flat steel product according to the invention is limited to a maximum of 1.5% by weight. -% limited. If a low austenitizing temperature is to be set in order to improve energy efficiency, Al contents of at most 0.2% by weight have proven to be expedient.
  • the sum of the Si content and half of the Al content is at least 0.9% by weight.
  • Values of less than 0.9% by weight increase the risk of cementite forming, through which carbon is bound and is no longer available for diffusion into the retained austenite during partitioning annealing and is therefore no longer available for stabilization of the retained austenite.
  • the N content in the steel of a flat steel product according to the invention is limited to 0.001-0.008% by weight.
  • nitrogen forms nitrides, for example with aluminum or titanium.
  • the steel should contain at least 0.001% by weight of N.
  • a preferred N content of at least 0.002% by weight can be set. Increasing N contents tend to lead to the formation of larger precipitates.
  • the N content is limited to a maximum of 0.008% by weight.
  • Phosphorus has a negative effect on the weldability in flat steel products according to the invention. For this reason, the P content should be as low as possible and in particular should not exceed 0.02% by weight.
  • chromium can be present in the steel in contents of up to 1.0% by weight.
  • Chromium is an effective inhibitor of pearlite and contributes to strength. This applies in particular to Cr contents of at least 0.01% by weight. With Cr contents of more than 1.0% by weight, however, the risk of pronounced grain boundary oxidation, which leads to a deterioration in the surface quality, is increased.
  • Molybdenum can likewise optionally be contained in the steel of a steel flat product according to the invention in amounts of at least 0.01% by weight in order to prevent the formation of pearlite. For reasons of cost, the Mo content is limited to levels of up to 0.2% by weight.
  • Boron can be contained as an optional alloying element in amounts of 0.001 to 0.01% by weight in the steel of a flat steel product according to the invention. Boron segregates onto the phase boundaries and thus blocks their movement. This supports the formation of a fine-grain structure, which improves the mechanical properties of the steel flat product.
  • alloying boron sufficient aluminum should be available so that AlN forms preferentially.
  • an Al/B ratio of at least 10 is therefore set. However, no further improvement can be achieved by adding boron in excess of 0.01% by weight.
  • steels of flat steel products according to the invention can also contain one or more micro-alloying elements from the group Ti, Nb and V.
  • Microalloying elements can form carbides, nitrides or carbonitrides with carbon or nitrogen. In the form of very finely distributed precipitations, these contribute to greater strength.
  • the sum of the micro-alloying elements should be at least 0.005% by weight, so that the precipitation of carbides, nitrides or carbonitrides can lead to the freezing of grain and phase boundaries during austenitizing and thus counteract grain coarsening.
  • carbon which in atomic form is favorable for stabilizing the retained austenite, is bound as carbide or carbonitride.
  • the total concentration of the micro-alloying elements should not exceed 0.2% by weight. To avoid coarse titanium nitride precipitates, the titanium concentration should not be more than 0.10%.
  • a flat steel product according to the invention has a yield point Rp02 of over 700 MPa or a yield point ReH of over 700 MPa, a tensile strength Rm of 950-1500 MPa and an elongation A80 of 7-25%, with the yield point Rp02 or the yield point ReH being the Tensile strength Rm and elongation A80 can be determined according to DIN EN ISO 6892:2009.
  • a flat steel product according to the invention has a high bake-hardening potential (BH potential).
  • a measure of the BH potential is the BH2 value, which is determined after pre-deformation of 2% and tempering for 20 minutes at 170° C.
  • the elongation A80_BH present after a BH treatment for 20 minutes at 170° C. on flat steel products according to the invention preformed by 2% is at least half as high as the elongation A80 before the BH treatment.
  • the elongation values A80 and A80_BH are determined according to DIN EN ISO 6892:2009.
  • the flat steel product according to the invention has a structure that contains no more than 15% by area of ferrite in order to ensure the required high strength.
  • the microstructure does not have more than 5% by area of bainite.
  • the microstructure of a flat steel product according to the invention contains at least 5% by volume of retained austenite. Residual austenite has a beneficial effect on the formability and elongation of martensite steels.
  • the austenite which has been stabilized down to room temperature, can be stretched more than other structural components using the TRIP effect with simultaneous higher hardening.
  • the austenite-stabilizing alloying elements such as C and Mn for reasons of weldability, a residual austenite content greater than 20% by volume is not possible with the manufacturing process described.
  • the flat steel product according to the invention contains at least 80% by area of martensite, of which at least 75% by area is tempered martensite.
  • the martensite formed in the course of the method according to the invention after the partitioning by the second quenching in step j) is also referred to as untempered martensite.
  • the martensite resulting from the first quench after austenitizing, which undergoes partitioning, is also known as tempered martensite. All of the martensite present in the structure is composed of tempered and untempered martensite, with the possibility that there is no untempered martensite.
  • the total proportion of martensite i.e. the sum of tempered and non-tempered martensite, should be at least 80% by area, preferably at least 90% by area. This high proportion of martensite contributes to the high strength of the flat steel product.
  • martensite is a carbon-rich structural component. As such, the martensite serves as a source for the diffusion of carbon both during the partitioning anneal and during the BH treatment.
  • the residual austenite present is stabilized by the carbon diffusion from the martensite into the austenite during the partitioning annealing, which makes it possible to set a residual austenite proportion of at least 5% by volume.
  • the carbon diffusion during the BH treatment increases the BH effect, resulting in an increase in the BH value.
  • At least 75% of the martensite present in the flat steel product is tempered martensite, because only then is there enough martensite available for adequate residual austenite stabilization during partitioning annealing.
  • At least 90% of the martensite lancets have a martensite lancet width of at most 1000 nm.
  • the narrow lancet width of at most 1000 nm leads to short diffusion paths during partitioning annealing, which enables targeted local stabilization of the retained austenite.
  • the martensite lancet length is limited to a maximum of 7.5 ⁇ m to ensure good formability. Since the lancets grow with a defined ratio of length to width, the width is limited, which has an advantageous effect on the diffusion of the carbon.
  • the information on the microstructural proportions for the microstructural components martensite, ferrite and bainite are based on area % and for retained austenite on vol. %. Due to the fineness of the microstructure, it is advisable to carry out the microstructure investigations, including the determination of the martensite lancet length and width, using a scanning electron microscope (SEM) at 5000x magnification. An examination using X-ray diffraction (XRD) according to ASTM E975 is recommended as a suitable method for the quantitative determination of retained austenite.
  • SEM scanning electron microscope
  • step a a hot-rolled flat steel product is provided, which consists of a steel of the composition mentioned in step a).
  • the hot-rolled flat steel product is pickled before cold rolling.
  • the pickling in step b) is carried out in a conventional manner.
  • the cold rolling in step c) should be carried out with a degree of cold rolling of at least 37%.
  • the degree of cold rolling KWG is understood to mean the reduction in thickness that occurs as a result of the cold rolling of the flat steel product.
  • h0 is the thickness of the flat steel product before the first cold rolling process or cold rolling pass in mm and h1 is the thickness of the flat steel product after the last cold rolling process or cold rolling pass in mm.
  • Cold rolling with a KWG of at least 37% results in mechanical homogenization and a reduction in grain size, resulting in a fine-grained structure. Due to the high degree of cold rolling and the precipitation processes and the resulting fine initial structure before annealing, a very fine-grained austenite structure is already present before cooling.
  • the grain boundaries act as an obstacle to the growth of martensite lancets, and the short distance between grain boundaries in a fine structure results in shorter and narrower lancets.
  • a structure of the finest martensite lancets with residual austenite embedded in between is created. In the subsequent treatment step, this leads to short diffusion paths, which means that targeted local stabilization of the retained austenite is possible.
  • the heating of the cold-rolled flat steel product in step d) to a holding zone temperature THZ takes place initially until a turning temperature TW is reached, which is 200-400° C., at a heating rate ThetaH1 of 5-50 K/s. Above the turning temperature TW, heating takes place at a heating rate ThetaH2 of 2 - 10 K/s until the holding zone temperature THZ is reached.
  • the heating can also take place in one step, i.e. the heating speeds ThetaH1 and ThetaH2 are set to the same value.
  • the steel flat product is heated to a holding zone temperature THZ, which is above the A3 temperature of the steel, in order to enable a complete transformation into austenite.
  • the holding zone temperature THZ can also be referred to as the austenitizing temperature and annealing at THZ can also be referred to as austenitizing.
  • the holding zone temperature is limited to a maximum of 950 °C.
  • step e) the flat steel product is held at the holding zone temperature THZ for a holding time tHZ of at least 5 seconds in order to ensure complete austenitization.
  • the holding time tHZ should not exceed 15 seconds in order to of a coarse austenite grain and irregular austenite grain growth.
  • the aim of austenitizing is to set a fine and regular austenite grain, since such a structure has a favorable effect on the BH value.
  • the flat steel product can optionally first be slowly cooled in step f) to an intermediate temperature TLK, which is 620° C. and at most 720° C. TLK is not lower than 620 °C to avoid phase transformation into ferrite. For the same reason, the duration tLK of the cooling from THZ to TLK is limited to 30 - 300 seconds.
  • the flat steel product is cooled in step g) at a higher cooling rate ThetaQ than the cooling rate in step f) of more than 5 K/s cooled to a cooling stop temperature TAB. Because of the high cooling rate, such cooling is also referred to as quenching or, to distinguish between quenching after partitioning annealing, the quenching in work step g) is also referred to as first quenching.
  • the cooling rate from the intermediate temperature TLK to the cooling stop temperature TAB is more than 5 K/s in order to avoid both the transformation of the austenite into ferrite and into bainite for the steel compositions according to the invention. This is even more reliable with higher cooling rates, which is why the ThetaQ cooling rate is preferably set to more than 20 K/s.
  • the cooling rate ThetaQ is technically limited to values of at most 500 K/s, preferably at most 100 K/s.
  • the cooling stop temperature TAB is between the martensite start temperature TMS and a temperature that is up to 175°C lower than TMS ((TMS-175°C) ⁇ TAB ⁇ TMS).
  • the martensite start temperature TMS is the temperature at which the transformation from austenite to martensite begins.
  • the extent of the transformation i.e. the proportion of martensite
  • the holding time tQ in step h) is at least 10 seconds to ensure sufficient conversion of the austenite into martensite.
  • the proportion of martensite produced by the first quenching after austenitizing should be at least 60% by area.
  • the holding time tQ should not be more than 60 seconds in order to avoid complete transformation into martensite and to ensure a residual austenite content of at least 5% by volume in the structure of the steel flat product at room temperature.
  • step i) the flat steel product is heated to a treatment temperature TB at a heating rate ThetaB1 and optionally maintained at TB in order to enrich the residual austenite present after step h) with carbon from the supersaturated martensite, which was formed by the first quenching.
  • the redistribution of the carbon which can also be referred to as partitioning, takes place during the heating phase on TB. If the flat steel product is then also held isothermally on TB, partitioning also takes place during the optional isothermic holding.
  • the heating to the treatment temperature TB and the subsequent optional holding at the treatment temperature TB are also referred to as partitioning annealing or partitioning.
  • heating is carried out at a heating rate of at least 1 K/s and at most 80 K/s.
  • the treatment temperature TB is 350 - 500 °C to avoid the formation of carbides and the decomposition of retained austenite.
  • the total treatment time is tBT at least 10 and at most 1000 seconds, also to ensure sufficient carbon redistribution.
  • the total treatment time tBT is made up of the time required for heating and, if applicable, the time used for the optional isothermal hold.
  • the flat steel product is then cooled to room temperature in step j) at a cooling rate ThetaB2.
  • the cooling rate ThetaB2 is more than 5 K/s, preferably more than 20 K/s to allow the formation of martensite.
  • This cooling step can also be referred to as quenching due to the high cooling rate.
  • the quenching in step j) is also referred to as second quenching.
  • the cooling rate ThetaB2 is technically limited to values of at most 500 K/s, preferably at most 100 K/s.
  • the flat steel product can additionally optionally be subjected to a coating treatment (step k)).
  • the coating treatment can be carried out either as a hot-dip coating (step k1)) or as an electrolytic coating (step k2)). If hot-dip coating takes place (work step k1)), the flat steel product, after partitioning in work step i) and before cooling in work step j), runs through a coating bath with a zinc-based molten bath composition.
  • the temperature of the molten bath is preferably 450-500.degree.
  • the flat steel product can be subjected to electrolytic coating (work step k2)).
  • the electrolytic coating does not take place before the flat steel product has been cooled in step j), but only after it has been cooled.
  • the coating treatment of steps k1) or k2) preferably takes place in a continuous process.
  • a possible molten bath composition can consist of up to 1% by weight Al, the remainder zinc and unavoidable impurities.
  • Another possible Molten bath composition may consist of 1-2 wt% Al, 1-2 wt% Mg, balance zinc and unavoidable impurities.
  • an anti-corrosion coating is applied to the flat steel product on at least one side of the flat steel product.
  • the coated flat steel product can also optionally be subjected to a galvannealing treatment.
  • the process according to the invention can be carried out continuously in annealing plants or coil coating plants which are usually provided for this purpose.
  • the cooling rate ThetaQ of the rapid cooling after austenitizing and the holding time tQ a microstructure results which has a very fine martensite structure.
  • This martensite structure is characterized by a particularly fine-grained structure with a narrow lancet width.
  • the high degree of cold rolling and the carbide and nitride precipitations lead to a fine-grained initial structure for austenitizing annealing.
  • coarsening of the grains during the austenitizing is avoided, so that a very fine-grained structure is already present before the cooling that follows the austenitizing.
  • the numerous grain boundaries of the fine structure hinder the growth of the martensite lancets.
  • Such a structure provides short diffusion paths for the carbon for the annealing process of the subsequent work step i) and thus enables targeted local stabilization of the retained austenite.
  • the flat steel products made available by the present invention are particularly suitable for further processing that includes a cold forming process and subsequent heat treatment at temperatures below 300.degree.
  • the production of components for automotive applications is mentioned here as an example.
  • Flat steel products are formed into components, for example painted using cathodic dip painting (KTL) and in a further process step subjected to heat treatment, for example during paint baking.
  • the heat treatment usually takes the form of heating within a temperature range of typically 120 to 250°C for a period of typically 3 to 40 minutes.
  • the flat steel products according to the present invention are particularly suitable for such applications.
  • the advantageous properties of the flat steel products according to the invention can also be used for products that have not been subjected to any pre-deformation.
  • the hot strips were pickled in a conventional manner and processed into cold strips with the cold rolling degrees "KWG” given in Table 2a. The further production of the cold strips took place in accordance with the information given in Table 2a and Table 2b.
  • the cold strips were each heated to a turning temperature "TW” at a first, faster heating rate “ThetaH1” and then at a second, slower heating rate “ThetaH2” brought to hold zone temperature "THZ" at which they were held for duration "tHZ".
  • the cold strips from tests 1-9 were first slowly cooled to an intermediate temperature "TLK” within a period of time “tLK”, then quickly quenched from the intermediate temperature "TLK” at a cooling rate "ThetaQ” to a cooling stop temperature "TAB”, at which they were held for a duration "tQ”.
  • the cold strip of test 10 was quickly quenched directly to the cool stop temperature "TAB” at a cooling rate "ThetaQ” without slow cooling and held at this temperature for the duration "tQ”.
  • the flat steel products were then subjected to partitioning for a time “tBT”, with them being heated to the partitioning temperature "TB” at a heating rate "ThetaB1". Finally, the steel flat products were quenched to room temperature with a cooling rate "ThetaB2". 10 tests were carried out, of which tests 4, 8 and 10 meet the requirements of the invention.
  • the structural investigations were carried out on cross sections at 1/3t layer, i.e. on sections which were taken at a third of the sheet thickness.
  • the sections were prepared for scanning electron microscopy (SEM) examination and treated with a 3% Nital etch. Due to the fineness of the microstructure, the microstructure was characterized by means of REM observation at a magnification of 5000x.
  • the quantitative determination of the retained austenite was carried out by means of X-ray diffraction (XRD) according to ASTM E975.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Electrochemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Claims (10)

  1. Produit plat en acier à haute résistance adapté au traitement de durcissement après cuisson, constitué d'un acier qui est constitué, en plus de fer et d'impuretés inévitables, de (en % en poids)
    C : 0,1 à 0,5 %,
    Si : 0,9 à 2,0 %,
    Mn : 1,0 à 3,0 %,
    Al : 0,02 à 1,5 %,
    N : 0,001 à 0,008 %,
    P : ≤ 0,02 %,
    S : ≤ 0,005 %,
    et éventuellement d'un ou de plusieurs des éléments suivants : Cr : 0,01 à 1,0 %, Mo : 0,01 à 0,2 %, B : 0,001 à 0,01 %,
    et éventuellement d'un total de 0,005 à 0,2 % de V, Ti et Nb, la proportion de Ti étant d'au plus 0,10 %,
    le produit plat en acier présentant une structure constituée
    - d'au plus 15 % en surface de ferrite,
    - d'au plus 5 % en surface de bainite,
    - d'au moins 5 % en volume d'austénite résiduelle et
    - d'au moins 80 % en surface de martensite, dont au moins 75 % en surface de martensite revenue,
    sur la base de la proportion totale de martensite dans la structure, celle-ci présentant une longueur de lancette de martensite d'au plus 7,5 µm et une largeur de lancette de martensite d'au plus 1 000 nm pour au moins 90 % de la martensite, mesurées comme indiqué dans la description, et
    le produit plat en acier présentant une limite d'allongement Rp02 de plus de 700 MPa ou une limite d'élasticité ReH de plus de 700 MPa, une résistance à la dilatation Rm de 950 à 1 500 MPa, un allongement A80 de 7 à 25 % et une valeur BH2, déterminée après une pré-déformation de 2 % et un revenu pendant 20 minutes à 170 °C conformément à la norme DIN EN 10325:2006, d'au moins 80 MPa.
  2. Produit plat en acier selon la revendication 1, caractérisé en ce que la teneur en carbone est d'au moins 0,14 % en poids.
  3. Produit plat en acier selon l'une des revendications précédentes, caractérisé en ce que la teneur en Al de l'acier du produit plat en acier est d'au moins 0,2 % en poids.
  4. Produit plat en acier selon l'une des revendications précédentes, caractérisé en ce qu'il est pourvu d'un revêtement anti-corrosion à base de zinc au moins sur une face.
  5. Procédé de fabrication d'un produit plat en acier à haute résistance adapté au traitement de durcissement après cuisson selon la revendication 1, comprenant les étapes de travail suivantes :
    a) fourniture d'un produit plat en acier laminé à chaud constitué d'un acier qui est constitué, en plus de fer et d'impuretés inévitables, de (en % en poids) 0,1 à 0,5 % de C, 1,0 à 3,0 % de Mn, 0,9 à 2,0 % de Si, 0,02 à 1,5 % de Al, 0,001 à 0,008 % de N, jusqu'à 0,02 % de P, jusqu'à 0,005 % de S et éventuellement d'un ou de plusieurs des éléments suivants : 0,01 à 1,0 % de Cr, 0,01 à 0,2 % de Mo, 0,001 à 0,01 % de B et éventuellement d'un total de 0,005 à 0,2 % de V, Ti et Nb, la proportion de Ti étant d'au plus 0,10 % ;
    b) décapage du produit plat en acier laminé à chaud ;
    c) laminage à froid du produit plat en acier à un degré de laminage à froid d'au moins 37 % ;
    d) chauffage du produit plat en acier laminé à froid à une température de zone de maintien THZ supérieure à la température A3 de l'acier et étant d'au plus 950 °C, le chauffage s'effectuant jusqu'à une température d'inflexion TW de 200 à 400 °C à une vitesse de chauffage ThetaH1 de 5 à 50 K/s et au-dessus de la température d'inflexion TW à une vitesse de chauffage ThetaH2 de 2 à 10 K/s ;
    e) maintien du produit plat en acier pendant 5 à 15 s à la température de zone de maintien THZ ;
    g) refroidissement éventuel du produit plat en acier pendant 30 à 300 secondes de la température de zone de maintien THZ jusqu'à une température intermédiaire TLK d'au moins 620 et d'au plus 720 °C ;
    f) refroidissement du produit plat en acier à une vitesse de refroidissement ThetaQ supérieure à 5 K/s en moyenne jusqu'à une température d'arrêt de refroidissement TAB comprise entre la température de début de martensite TMS et une température inférieure jusqu'à 175 °C à la TMS ;
    h) maintien du produit plat en acier à la température d'arrêt de refroidissement TAB pendant 10 à 60 secondes ;
    i) chauffage du produit plat en acier à une vitesse de chauffage ThetaB1, qui est de 1 à 80 K/s, à une température de traitement TB de 350 à 500 °C et éventuellement maintien isotherme du produit plat en acier à la température de traitement TB, la durée du chauffage et du maintien isotherme éventuel étant au total de 10 à 1 000 secondes ;
    j) refroidissement du produit plat en acier à une vitesse de refroidissement ThetaB2 supérieure à 5 K/s et inférieure à 500 K/s à température ambiante
    k) revêtement éventuel du produit plat en acier dans un bain fondu soit
    k1) au moyen d'un revêtement par immersion à chaud avant le refroidissement à l'étape de travail j)
    ou soit
    k2) au moyen d'un revêtement électrolytique après le refroidissement à l'étape de travail j).
  6. Procédé selon la revendication 5, caractérisé en ce que le degré de laminage à froid à l'étape de travail c) est d'au moins 42 %.
  7. Procédé selon la revendication 5 ou 6, caractérisé en ce que le produit plat en acier traverse un bain de fusion à base de zinc à l'étape de travail k).
  8. Procédé selon la revendication 7, caractérisé en ce que la composition de bain de fusion à l'étape de travail k) est constituée de 1 à 2 % en poids d'AI, de 1 à 2 % en poids de Mg, et de reste de zinc et d'impuretés inévitables.
  9. Procédé selon l'une des revendications 5 à 8, caractérisé en ce que le traitement de revêtement éventuel à l'étape de travail k) a lieu dans un processus continu.
  10. Procédé selon l'une des revendications 5 à 9, caractérisé en ce que la vitesse de refroidissement ThetaB2 à l'étape de travail j) est supérieure à 20 K/s.
EP17780063.8A 2017-09-28 2017-09-28 Produit d'acier plat et son procédé de fabrication Active EP3688203B1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PL17780063.8T PL3688203T3 (pl) 2017-09-28 2017-09-28 Płaski wyrób stalowy i sposób jego wytwarzania
EP22159990.5A EP4043603A1 (fr) 2017-09-28 2017-09-28 Produit plat en acier et son procédé de fabrication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2017/074642 WO2019063081A1 (fr) 2017-09-28 2017-09-28 Produit plat en acier et son procédé de fabrication

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP22159990.5A Division EP4043603A1 (fr) 2017-09-28 2017-09-28 Produit plat en acier et son procédé de fabrication
EP22159990.5A Division-Into EP4043603A1 (fr) 2017-09-28 2017-09-28 Produit plat en acier et son procédé de fabrication

Publications (2)

Publication Number Publication Date
EP3688203A1 EP3688203A1 (fr) 2020-08-05
EP3688203B1 true EP3688203B1 (fr) 2022-04-27

Family

ID=60019885

Family Applications (2)

Application Number Title Priority Date Filing Date
EP17780063.8A Active EP3688203B1 (fr) 2017-09-28 2017-09-28 Produit d'acier plat et son procédé de fabrication
EP22159990.5A Withdrawn EP4043603A1 (fr) 2017-09-28 2017-09-28 Produit plat en acier et son procédé de fabrication

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP22159990.5A Withdrawn EP4043603A1 (fr) 2017-09-28 2017-09-28 Produit plat en acier et son procédé de fabrication

Country Status (6)

Country Link
EP (2) EP3688203B1 (fr)
JP (1) JP7105302B2 (fr)
CN (1) CN111148853B (fr)
ES (1) ES2921013T3 (fr)
PL (1) PL3688203T3 (fr)
WO (1) WO2019063081A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3807429A1 (fr) 2018-06-12 2021-04-21 ThyssenKrupp Steel Europe AG Produit plat en acier et procédé de fabrication
ES2889200T3 (es) * 2019-01-22 2022-01-11 Voestalpine Stahl Gmbh Tira o chapa de acero de fase compleja laminado en frío de alta resistencia y alta ductilidad
WO2020151856A1 (fr) * 2019-01-22 2020-07-30 Voestalpine Stahl Gmbh Bande ou tôle d'acier à phase complexe, laminée à froid, très résistante et hautement ductile
EP3754035B1 (fr) 2019-06-17 2022-03-02 Tata Steel IJmuiden B.V. Procédé de traitement thermique d'une bande d'acier laminée à froid
ES2911662T3 (es) 2019-06-17 2022-05-20 Tata Steel Ijmuiden Bv Método de tratamiento térmico de un fleje de acero laminado en frío de alta resistencia
MX2021015578A (es) * 2019-06-28 2022-01-24 Nippon Steel Corp Lamina de acero.
CN115537635B (zh) * 2022-09-16 2024-01-23 北京科技大学 一种基于trip效应的颗粒增强型耐磨钢板nm300及其制备方法

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4173618B2 (ja) * 2000-03-07 2008-10-29 株式会社神戸製鋼所 高強度高靭性マルテンサイト鋼の製造方法
JP4411751B2 (ja) * 2000-06-28 2010-02-10 アイシン精機株式会社 ギヤ部分付き平板状部材
WO2012073538A1 (fr) 2010-11-29 2012-06-07 新日本製鐵株式会社 Tôle d'acier laminée à froid à haute résistance et à durcissement après cuisson, et son procédé de fabrication
EP2524970A1 (fr) * 2011-05-18 2012-11-21 ThyssenKrupp Steel Europe AG Produit plat en acier hautement résistant et son procédé de fabrication
JP5857909B2 (ja) * 2012-08-09 2016-02-10 新日鐵住金株式会社 鋼板およびその製造方法
JP6234845B2 (ja) 2014-03-06 2017-11-22 株式会社神戸製鋼所 焼付け硬化性と曲げ性に優れた高強度合金化溶融亜鉛めっき鋼板
JP6179461B2 (ja) * 2014-05-27 2017-08-16 Ｊｆｅスチール株式会社 高強度鋼板の製造方法
WO2016079565A1 (fr) * 2014-11-18 2016-05-26 Arcelormittal Procédé de fabrication d'un produit en acier haute résistance et produit en acier ainsi obtenu
JP6282577B2 (ja) * 2014-11-26 2018-02-21 株式会社神戸製鋼所 高強度高延性鋼板
WO2016129214A1 (fr) * 2015-02-13 2016-08-18 Ｊｆｅスチール株式会社 Tôle d'acier galvanisée par immersion à chaud à haute résistance et procédé de fabrication s'y rapportant
JP6540131B2 (ja) * 2015-03-20 2019-07-10 日本製鉄株式会社 フェライト系耐熱鋼
JP6554396B2 (ja) * 2015-03-31 2019-07-31 株式会社神戸製鋼所 加工性および衝突特性に優れた引張強度が９８０ＭＰａ以上の高強度冷延鋼板、およびその製造方法
WO2016177420A1 (fr) * 2015-05-06 2016-11-10 Thyssenkrupp Steel Europe Ag Produit laminé plat en acier et son procédé de fabrication
KR101767818B1 (ko) * 2016-03-08 2017-08-11 주식회사 포스코 소부경화성 및 내시효성이 우수한 용융 아연계 도금강판 및 그 제조방법

Also Published As

Publication number Publication date
CN111148853A (zh) 2020-05-12
CN111148853B (zh) 2022-04-15
ES2921013T3 (es) 2022-08-16
EP3688203A1 (fr) 2020-08-05
WO2019063081A1 (fr) 2019-04-04
EP4043603A1 (fr) 2022-08-17
PL3688203T3 (pl) 2022-08-29
JP2021503040A (ja) 2021-02-04
JP7105302B2 (ja) 2022-07-22

Similar Documents

Publication Publication Date Title
EP3688203B1 (fr) Produit d'acier plat et son procédé de fabrication
EP2710158B1 (fr) Produit plat en acier hautement résistant et son procédé de fabrication
DE60125253T2 (de) Hochfestes warmgewalztes Stahlblech mit ausgezeichneten Reckalterungseigenschaften
EP3292228B1 (fr) PRODUIT EN ACIER PLAT ET PROCÉDÉ DE FABRICATION DE
CELLE-CI
EP3027784B1 (fr) Acier multiphase à haute résistance, micro-allié et contenant du silicium, présentant une résistance minimale à la traction de 750 mpa et des propriétés améliorées et procédé de fabrication d'une bande à partir de cet acier
EP3221484B1 (fr) Procédé de production d'une bande en acier polyphasé, durcissant à l'air, ayant une haute résistance et ayant d'excellentes propriétés de mise en oeuvre
EP3221478B1 (fr) Bande à chaud ou à froid d'un acier multiphasé à haute résistance durcissant à l'air qui présente d'excellentes propriétés de traitement et procédé de fabrication d'une bande à chaud ou à froid à partir de cet acier multiphasé à haute résistance durcissant à l'air
EP3320120A1 (fr) Acier multiphase à haute résistance et procédé de fabrication d'une bande d'acier laminée à froid composée dudit acier
WO2009021897A1 (fr) Acier biphasé, produit plat constitué d'un tel acier biphasé et procédé de fabrication d'un produit plat
EP3221483B1 (fr) Acier multiphases autotrempant en profondeur à haute résistance mécanique avec excellent aptitude au faconnage et procédé de fabrication d'une bande de cet acier
EP2935635A1 (fr) Procédé de traitement thermique d'un produit en acier au manganèse et produit en acier au manganèse
DE102017123236A1 (de) Höchstfester Mehrphasenstahl und Verfahren zur Herstellung eines Stahlbandes aus diesem Mehrphasenstahl
EP3856936B1 (fr) Procédé pour la préparation d'un produit plat en acier revêtu et produit plat en acier revêtu
WO2019238741A1 (fr) Produit plat en acier et procédé de fabrication
DE60210767T2 (de) Hochzugfestes warmgewalztes stahlblech mit hervorragender masshaltigkeit und hervorragenden dauerfestigkeitseigenschaften nach dem formen
WO2020038883A1 (fr) Produit plat en acier laminé à chaud n'ayant pas subi un traitement par trempe et revenu, laminé à chaud ayant subi un traitement par trempe et revenu, ainsi que procédé de production associé
EP3872206B1 (fr) Procédé de fabrication d'un produit plan en acier laminé à froid, traité ultérieurement et produit plan en acier laminé à froid, traité ultérieurement
WO2024170670A1 (fr) Acier à haute résistance à la traction ayant une résistance améliorée à la fragilisation par l'hydrogène
WO2024149909A1 (fr) Acier à haute résistance à la traction ayant une résistance améliorée à la fragilisation par l'hydrogène
EP4139492A1 (fr) Produit d'acier plat laminé à chaud et son procédé de fabrication

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20200207

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20210510

RAP3 Party data changed (applicant data changed or rights of an application transferred)

Owner name: THYSSENKRUPP STEEL EUROPE AG

Owner name: THYSSENKRUPP AG

RIN1 Information on inventor provided before grant (corrected)

Inventor name: THIESSEN, RICHARD GEORG

Inventor name: IRNICH, MANUELA

Inventor name: LINKE, BERND

Inventor name: RUDOLPH, JAN-HENDRIK

Inventor name: FECHTE-HEINEN, RAINER

REG Reference to a national code

Ref country code: DE

Ref legal event code: R079

Ref document number: 502017013084

Country of ref document: DE

Free format text: PREVIOUS MAIN CLASS: C22C0038000000

Ipc: C21D0001220000

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

RIC1 Information provided on ipc code assigned before grant

Ipc: C21D 8/04 20060101ALN20211001BHEP

Ipc: C21D 9/48 20060101ALN20211001BHEP

Ipc: C21D 6/00 20060101ALN20211001BHEP

Ipc: C23C 2/28 20060101ALI20211001BHEP

Ipc: C25D 7/06 20060101ALI20211001BHEP

Ipc: C25D 5/36 20060101ALI20211001BHEP

Ipc: C22C 38/04 20060101ALI20211001BHEP

Ipc: C22C 38/02 20060101ALI20211001BHEP

Ipc: C22C 38/00 20060101ALI20211001BHEP

Ipc: C21D 8/02 20060101ALI20211001BHEP

Ipc: C22C 38/06 20060101ALI20211001BHEP

Ipc: C21D 8/00 20060101ALI20211001BHEP

Ipc: C22C 38/12 20060101ALI20211001BHEP

Ipc: C22C 38/18 20060101ALI20211001BHEP

Ipc: C21D 9/46 20060101ALI20211001BHEP

Ipc: C22C 38/14 20060101ALI20211001BHEP

Ipc: C23C 2/00 20060101ALI20211001BHEP

Ipc: C23C 2/04 20060101ALI20211001BHEP

Ipc: C23C 2/06 20060101ALI20211001BHEP

Ipc: C23C 2/34 20060101ALI20211001BHEP

Ipc: C23C 2/40 20060101ALI20211001BHEP

Ipc: C21D 1/22 20060101AFI20211001BHEP

INTG Intention to grant announced

Effective date: 20211104

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 1486973

Country of ref document: AT

Kind code of ref document: T

Effective date: 20220515

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502017013084

Country of ref document: DE

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

REG Reference to a national code

Ref country code: NL

Ref legal event code: FP

REG Reference to a national code

Ref country code: SE

Ref legal event code: TRGR

REG Reference to a national code

Ref country code: FI

Ref legal event code: FGE

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2921013

Country of ref document: ES

Kind code of ref document: T3

Effective date: 20220816

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG9D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220829

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220727

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220728

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220727

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220827

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502017013084

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

26N No opposition filed

Effective date: 20230130

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220928

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230526

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220930

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220928

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220930

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CZ

Payment date: 20230918

Year of fee payment: 7

Ref country code: AT

Payment date: 20230921

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20230920

Year of fee payment: 7

Ref country code: PL

Payment date: 20230919

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20231124

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20230927

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20170928

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20220427

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FI

Payment date: 20240918

Year of fee payment: 8

Ref country code: DE

Payment date: 20240918

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20240920

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20240918

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20240925

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20240918

Year of fee payment: 8