EP4455338A1 - Warmgewalzter stahl für hyperrohre und herstellungsverfahren dafür - Google Patents

Warmgewalzter stahl für hyperrohre und herstellungsverfahren dafür Download PDF

Info

Publication number
EP4455338A1
EP4455338A1 EP22911814.6A EP22911814A EP4455338A1 EP 4455338 A1 EP4455338 A1 EP 4455338A1 EP 22911814 A EP22911814 A EP 22911814A EP 4455338 A1 EP4455338 A1 EP 4455338A1
Authority
EP
European Patent Office
Prior art keywords
hot
steel sheet
rolled steel
amount
slab
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.)
Pending
Application number
EP22911814.6A
Other languages
English (en)
French (fr)
Other versions
EP4455338A4 (de
Inventor
Hong-Seok Yang
Nam-Il Jo
Jin-Joo CHOI
Seung-Gohn KIM
Seok-Jong SEO
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.)
Posco Holdings Inc
Original Assignee
Posco Co Ltd
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 Posco Co Ltd filed Critical Posco Co Ltd
Publication of EP4455338A1 publication Critical patent/EP4455338A1/de
Publication of EP4455338A4 publication Critical patent/EP4455338A4/de
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • 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
    • C21D8/0221—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 characterised by the working steps
    • C21D8/0226—Hot 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 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
    • C21D8/0247—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 characterised by the heat treatment
    • C21D8/0263—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 characterised by the heat treatment following hot 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • 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
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/18—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
    • 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
    • C21D2211/009—Pearlite

Definitions

  • the present disclosure relates to a hot-rolled steel sheet and a manufacturing method therefor, and more specifically, to a hot-rolled steel sheet having properties suitable for a vacuum train tube, and a manufacturing method therefor.
  • a vacuum train also known as a hyperloop train, may be a system in which a magnetically levitated train moves inside a vacuum tube.
  • Such a train is capable of operating at an ultra-high speed because there is no friction with air or a track, which is the main cause of energy loss when running a train.
  • Such a vacuum train may have low energy loss to conserve 93% of energy, as compared to an airplane, and may thus be in the spotlight as an eco-friendly next-generation means of transportation, and active research thereon is being conducted around the world.
  • a structure and material of the vacuum tube used in such a high-speed vacuum train may affect performance and costs of the system.
  • a first material thereamong may be a concrete material.
  • a concrete tube is advantageous in terms of costs, but individual tubes of about 10 meters in length may not be easy to be interconnected.
  • a second material thereamong which is attracting a lot of research, may be a composite material such as a carbon fiber or the like.
  • the composite material such as a carbon fiber or the like may be light and have high performance, but high costs may be considered as the biggest disadvantage thereof.
  • a third material which may be most promising for the vacuum train tube, may be steel materials.
  • -Steel materials may be materials that may be mass-produced at low cost.
  • Steel materials may be materials that have high rigidity and strength and are easy to process.
  • Steel materials may be also materials that are easy to assemble or weld a component between tubes or to a tube, and have an appropriate outgassing rate when maintaining a vacuum.
  • ultra-high-speed vacuum trains operate at significantly faster speeds than current high-speed trains, safety of passengers and surrounding facilities should be considered a top priority.
  • safety standards for ultra-high-speed vacuum trains have not been established, and development of materials for tubes to ensure safety of ultra-high-speed vacuum trains may be also insufficient.
  • the vacuum trains should also ensure high efficiency to match the trends of the times, the development of materials for tube to maximize energy efficiency of the vacuum trains may be also insufficient.
  • Patent Document 1 Korean Patent No. 10-2106353 (May 4, 2020 )
  • the present disclosure seeks to provide a hot-rolled steel sheet for a vacuum train tube having excellent structural stability, and a manufacturing method therefor.
  • the present disclosure is to provide a hot-rolled steel sheet for a vacuum train tube maximizing energy efficiency of a vacuum train, and a manufacturing method therefor.
  • a hot-rolled steel sheet for a vacuum train tube includes, by weight, carbon (C): 0.03 to 0.11%, silicon (Si): 1.0 to 2.0%, manganese (Mn): 1.2 to 2.2%, a balance of Fe, and inevitable impurities, wherein a microstructure comprises a composite structure in which pearlite is dispersed in a matrix structure of ferrite.
  • An average particle size (D F , pm) of the ferrite and an average aspect ratio (A F ) of the ferrite may satisfy the following relational expression 1: 7 ⁇ D F / A F ⁇ 20
  • the average particle size (D F ) of the ferrite may satisfy a range of 8 to 20 ⁇ m.
  • the average aspect ratio (A F ) of the ferrite may be 2 or less.
  • An amount of carbon (C) of the hot-rolled steel sheet may be 0.05 to 0.09 wt%.
  • An amount of silicon (Si) of the hot-rolled steel sheet may be 1.4 to 1.8 wt%.
  • An amount of manganese (Mn) of the hot-rolled steel sheet may be 1.5 to 1.9 wt%.
  • a total amount of titanium (Ti), niobium (Nb), and vanadium (V), inevitably included in the hot-rolled steel sheet, may be less than 0.01% (including 0%).
  • the hot-rolled steel sheet may include one or more selected from chromium (Cr), nickel (Ni), copper (Cu), molybdenum (Mo), and tungsten (W), in a total amount of 1.0% or less (including 0%).
  • the hot-rolled steel sheet may satisfy any one or more of the following relational expressions 2 to 5 for the hot-rolled steel sheet: 355 ⁇ 11 + 394 * D F ⁇ 0.5 + 448 * C + 94 * Si + 69 * Mn 100 ⁇ 186 - 240*D F (-0.5) - 121*[C] - 13.2*[Si] + 13.7*[Mn]
  • D F is an average particle size (pm) of ferrite included in the hot-rolled steel sheet
  • [C], [Si], and [Mn] are an amount of carbon (C), an amount of silicon (Si), and an amount of manganese (Mn), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • the microstructure of the hot-rolled steel sheet may comprise 60 to 90 area% of ferrite, 10 to 40 area% of pearlite, and an inevitable structure.
  • Yield strength of the hot-rolled steel sheet may be 350 MPa or more, and a Charpy impact energy of the hot-rolled steel sheet at -20°C may be 27 J or more.
  • a vibration damping ratio measured at a frequency of 1650Hz in a flexural vibration mode, after processing the hot-rolled steel sheet into a specimen with a length*width*thickness of 80mm*20mm*2mm, may be 100*10 -6 or more.
  • An electrical resistivity of the hot-rolled steel sheet may be 35*10 -8 Qm or more.
  • YR RD is a yield ratio in a direction, parallel to a rolling direction of the hot-rolled steel sheet
  • YR TD is a yield ratio in a direction, perpendicular to the rolling direction of the hot-rolled steel sheet
  • YR RD - YR TD is an absolute value of a difference between the yield ratio (YR RD ) in a direction, parallel to the rolling direction and the yield ratio (YR TD ) in a direction, perpendicular to the rolling direction.
  • a Charpy impact energy of the welded portion at -20°C may be 27 J or more, and a fraction of an M-A phase included in the welded portion may be 5 area% or less (including 0%).
  • a thickness of the hot-rolled steel sheet may be 10 mm or more.
  • a method for manufacturing a hot-rolled steel sheet for a vacuum train tube includes heating a slab to a heating temperature (T 1 ) of 1100°C to 1300°C, wherein the slab includes, by weight, carbon (C) : 0.03 to 0.11%, silicon (Si): 1.0 to 2.0%, manganese (Mn): 1.2 to 2.2%, a balance of Fe, and inevitable impurities; hot-rolling the heated slab at a finish rolling temperature (T 2 ) of 900°C to 1000°C to provide a hot-rolled steel sheet; and coiling the hot-rolled steel sheet at a coiling temperature (T 3 ) of 600°C to 700°C, wherein the finish rolling temperature (T 2 ) and the coiling temperature (T 3 ) satisfy the following relational expression 7: 10 ⁇ -101.9 + 0.103*[T 2 ] + 0.0339*[T 3 ] - 61.9* [C] - 190.2*[Nb] ⁇ 20
  • [T 2 ] and [T 3 ] are the finish rolling temperature (T 2 , °C) and the coiling temperature (T 3 , °C), [C] and [Nb] are an amount of carbon (C) and an amount of niobium (Nb), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • An amount of carbon (C) of the slab may be 0.05 to 0.09 wt%.
  • An amount of silicon (Si) of the slab may be 1.4 to 1.8 wt%.
  • An amount of manganese (Mn) of the slab may be 1.5 to 1.9 wt%.
  • a total amount of titanium (Ti), niobium (Nb), and vanadium (V), inevitably included in the slab, may be less than 0.01% (including 0%).
  • the slab may include one or more selected from chromium (Cr), nickel (Ni), copper (Cu), molybdenum (Mo), and tungsten (W), in a total amount of 1.0% or less (including 0%) .
  • a thickness of the hot-rolled steel sheet may be 10 mm or more.
  • a hot-rolled steel sheet having excellent yield strength, yield ratio, vibration damping ratio, and low-temperature toughness, and low anisotropy of the yield ratio which has physical properties suitable for vacuum train tubes, and a method for manufacturing the same, may be provided.
  • the present disclosure relates to a hot-rolled steel sheet for a vacuum train tube and a manufacturing method therefor, and hereinafter, preferred embodiments of the present disclosure will be described.
  • Embodiments of the present disclosure may be modified in various forms, and the scope of the present disclosure should not be construed as being limited to embodiments described below.
  • the present embodiments may be provided to describe the present disclosure in more detail to those skilled in the art to which the present disclosure pertains.
  • a vacuum train may be a train that runs inside a tube in a vacuum or sub-vacuum state, and may be a next-generation transportation vehicle currently in an early stage of development.
  • the vacuum train may be a means of transportation that may effectively achieve high speed and high efficiency by eliminating frictional resistance between wheels and tracks and minimizing air resistance.
  • due to nature of the vacuum train operating at ultra-high speeds there may be a risk of large-scale accidents occurring when safety of the vacuum train is not sufficiently secured.
  • a material for a vacuum train tube requires more stringent safety measures.
  • the inventor of the present disclosure found that the following characteristics are important as a material for the vacuum tube to ensure safety of the vacuum train.
  • a material for the vacuum tube has high strength characteristics. Since the vacuum train moves through an internal space of the vacuum tube, the material for vacuum tube may be required to have sufficient strength as a structure. Additionally, since the internal space of the vacuum tube should be maintained in a vacuum or sub-vacuum state, it is required to have sufficient strength characteristics to prevent a shape of the tube from being deformed due to a difference in pressure between the internal space and an external space.
  • the material for vacuum tube has excellent vibration damping ability.
  • a pod in which several dozen people are on board may pass through the internal space of the vacuum tube at intervals of tens of seconds to several minutes.
  • vibration may be amplified within the vacuum tube, causing resonance, and in serious cases, it may even cause damage to the tube. Therefore, when a material having a vibration damping ratio above a certain level is applied to the vacuum tube, vibration within the tube may be effectively reduced after passing the preceding pod, and may effectively contribute to safety of the vacuum train.
  • the material for vacuum tube has excellent low-temperature toughness.
  • the vacuum train may also operate in polar regions or deep oceans. Iron and steel materials tend to be more easily damaged in a low-temperature environment or an extremely low-temperature environment. Therefore, when iron and steel are applied to the vacuum tube, it is required to have a certain level of low-temperature toughness to ensure safety.
  • excellent low-temperature toughness may be required not only in a base material but also in a welded portion.
  • the material for vacuum tube has excellent buckling resistance and earthquake resistance properties.
  • a compressive load may be applied to the vacuum tube along a length of the vacuum tube due to operation of the vacuum train or influence of a surrounding environment.
  • buckling a phenomenon in which the vacuum tube suddenly bends in a direction, perpendicular to a load direction, may occur.
  • an earthquake of a certain magnitude or higher occurs in a region in which the vacuum tube is installed, the vacuum tube may be structurally damaged or collapse. Therefore, the material for vacuum tube may be required to have excellent buckling resistance and earthquake resistance properties to ensure structural safety, and such properties may be secured by lowering the yield ratio of the material.
  • the vacuum tube When a yield ratio of the material is anisotropic, the vacuum tube may be easily damaged or bent, even when a load significantly lower than the critical load is applied to the vacuum tube in a specific direction. Therefore, it is advantageous for the material for vacuum tubes to have a low yield ratio and have a small deviation in yield ratio value depending on a direction.
  • the vacuum train may minimize friction between a track and a train through magnetic levitation, and the methods of levitating the train may be broadly divided into an electromagnetic suspension (EMS) method and an electrodynamic suspension (EDS) method.
  • the electromagnetic suspension (EMS) method may use attractive force between (electro)magnets to levitate the train, and the electrodynamic suspension (EDS) method may use repulsive force between a superconductor and a magnet.
  • Both the electrodynamic suspension (EDS) method and the electromagnetic suspension (EMS) method may form a strong magnetic field around the vacuum train, which is running, and a change in magnetic field, as above, may form an induced current in the vacuum tube. Since generation of such induced current means energy loss, it is necessary to reduce such energy loss by increasing electrical resistivity of the material for vacuum tube.
  • the inventor of the present disclosure strictly controlled alloy composition amounts and a microstructure of the steel sheet, to improve yield strength, a yield ratio, a vibration damping ratio, low-temperature toughness, and electrical resistivity, and lower anisotropy of the yield ratio. After recognizing this, the present disclosure was developed.
  • a hot-rolled steel sheet for a vacuum train tube includes, by weight, carbon (C) : 0.03 to 0.11%, silicon (Si): 1.0 to 2.0%, manganese (Mn): 1.2 to 2.2%, a balance of Fe, and inevitable impurities, wherein a composite structure in which pearlite is dispersed in a matrix structure of ferrite is included as a microstructure.
  • Carbon (C) may be a component that has a very large impact on strength of a steel sheet.
  • the present disclosure may include 0.03% or more of carbon (C) to ensure strength required for a structure.
  • a preferable lower limit of the amount of carbon (C) may be 0.04%, and a more preferable lower limit of the amount of carbon (C) may be 0.05%.
  • the carbon (C) content is excessive, toughness of the material may decrease, weldability may deteriorate, and a yield ratio may increase.
  • an amount of carbon (C) is excessive, it may be difficult to coarsen crystal grains. Therefore, the present disclosure limits an upper limit of the amount of carbon (C) to 0.11%.
  • a preferable upper limit of the amount of carbon (C) is 0.10%, and a more preferable upper limit of the amount of carbon (C) is 0.09%.
  • silicon (Si) may combine with oxygen to form a slag in steelmaking, silicon (Si) tends to be removed along with oxygen. Additionally, silicon (Si) may be also a component that effectively contributes to improving strength of a material. Therefore, the present disclosure may include 1.0% or more of silicon (Si) for this effect.
  • a preferable lower limit of the amount of silicon (Si) is 1.2%, and a more preferable lower limit of the amount of silicon (Si) is 1.4%.
  • an amount of silicon (Si) when an amount of silicon (Si) is excessive, low-temperature toughness of a welded portion may be reduced by promoting formation of an M-A phase (a martensite-austenite complex) in the welded portion, the present disclosure may limit an amount of silicon (Si) to 2.0% or less.
  • a preferable upper limit of the amount of silicon (Si) is 1.9%, and a more preferable upper limit of the amount of silicon (Si) is 1.8%.
  • Manganese (Mn) may be a component that improves strength and hardenability of steel. Therefore, the present disclosure may include 1.2% or more of manganese (Mn) to ensure this effect.
  • a preferable lower limit of the amount of manganese (Mn) is 1.3%, and a more preferable lower limit of the amount of manganese (Mn) is 1.5%.
  • the amount of manganese (Mn) is limited to 2.2% or less.
  • a preferable upper limit of the amount of manganese (Mn) is 2.1%, and a more preferable upper limit of the amount of manganese (Mn) is 1.9%.
  • the hot-rolled steel sheet according to an aspect of the present disclosure may further include one or more selected from chromium (Cr), nickel (Ni), copper (Cu), molybdenum (Mo), and tungsten (W), in addition to the above-described alloy components.
  • chromium (Cr), nickel (Ni), copper (Cu), molybdenum (Mo), and tungsten (W) may contribute to improving the strength of the hot-rolled steel sheet.
  • a carbon equivalent (Ceq) may be excessively high, but also costs therefrom may increase.
  • a total amount of one or more selected from chromium (Cr), nickel (Ni), copper (Cu), molybdenum (Mo), and tungsten (W) may be 1.0% or less.
  • the total amount of one or more selected from chromium (Cr), nickel (Ni), copper (Cu), molybdenum (Mo), and tungsten (W) may be 0.5%, and cases in which the total amount of the components is 0% may be included.
  • a hot-rolled steel sheet according to an aspect of the present disclosure may include a remaining Fe and other inevitable impurities in addition to the above-mentioned components.
  • unintended impurities from raw materials or surrounding environment may be inevitably mixed, and thus this may not be entirely excluded. Since all of these impurities may be known to anyone skilled in the art, all of the contents may not be specifically mentioned in the present specification.
  • additional components effective in addition to the above-described components may not be entirely excluded.
  • a hot-rolled steel sheet according to an aspect of the present disclosure may actively suppress addition of titanium (Ti), niobium (Nb), and vanadium (V), and even when these components are inevitably included, the total amount thereof may limit less than 0.01% (including 0%). Titanium (Ti), niobium (Nb), and vanadium (V) may be representative precipitation strengthening elements that effectively contribute to improving strength of steel by generating fine carbonitrides. Since titanium (Ti), niobium (Nb), and vanadium (V) may excessively refine a microstructure of the steel, which may be detrimental to securing vibration damping ability, the present disclosure is seeks to actively suppress these components.
  • titanium (Ti), niobium (Nb), and vanadium (V) may be expensive components, and may be undesirable from an economic perspective.
  • the present disclosure may not artificially add these components, and even when they are unavoidably added, the total amount of these components may be actively suppressed to be less than 0.01%.
  • the total amount of these components is 0.005% or less, and more preferably, the total amount of these components is 0%.
  • a hot-rolled steel sheet according to an aspect of the present disclosure may have a composite structure in which pearlite is dispersed in a matrix structure of ferrite as a microstructure.
  • the matrix structure may be interpreted to mean a structure that occupies 50 area% or more, when observing the microstructure of the hot-rolled steel sheet.
  • a hot-rolled steel sheet according to an aspect of the present disclosure may actively suppress creation of low-temperature structures such as bainite, martensite, or the like.
  • a steel sheet having a low-temperature structure such as bainite, martensite, or the like may have high strength and a low yield ratio, and may thus exhibit excellent properties as a structural material. Since a hot-rolled steel sheet for a vacuum train tube targeted by the present disclosure may be thick at a level of 10 mm or more, a low-temperature structure may be formed only on a surface of the steel sheet, and it may be difficult to sufficiently generate the low-temperature structure up to a central portion of the steel sheet.
  • a fraction thereof may be actively suppressed to 1 area% or less (including 0%).
  • a fraction of ferrite may be 60 to 90 area%, and a fraction of pearlite may be 10 to 40 area%.
  • the present disclosure may limit an average particle size (D F , pm) of ferrite to a certain range. As a grain size increases, it may be more advantageous to secure the vibration damping ratio. Therefore, the present disclosure may limit the average particle size (D F , pm) of ferrite to 8 pm or more. When the grain size is excessively large, strength and low-temperature toughness of a material may deteriorate. Therefore, the present disclosure may limit the average particle size (D F , pm) of ferrite to 20 pm or less.
  • D F means an average particle size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
  • a F means an average aspect ratio of ferrite
  • D F is an average particle size (pm) of ferrite included in the hot-rolled steel sheet
  • [C], [Si], and [Mn] are an amount of carbon (C), an amount of silicon (Si), and an amount of manganese (Mn), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • D F is an average particle size (pm) of ferrite included in the hot-rolled steel sheet
  • [C], [Si], and [Mn] are an amount of carbon (C), an amount of silicon (Si), and an amount of manganese (Mn), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • a hot-rolled steel sheet for a vacuum train tube may satisfy any one or more of the above-described alloy component amounts and relational expressions 1 to 5, and thus a desired level of yield strength, yield ratio, material anisotropy, base material low-temperature toughness, vibration damping ratio, electrical resistivity, and low-temperature toughness of the welded portion may be secured.
  • a hot-rolled steel sheet for a vacuum train tube according to an aspect of the present disclosure may have a yield strength of 350 MPa or more and a Charpy impact energy at -20°C of 27 J or more. Therefore, the hot-rolled steel sheet for a vacuum train tube of the present disclosure may secure suitable strength and low-temperature toughness as a structural material, and may effectively ensure the structural safety of the vacuum train tube.
  • a hot-rolled steel sheet for a vacuum train tube may have a vibration damping ratio of 100*10 -6 or more.
  • the vibration damping ratio refers to a vibration damping ratio measured at a frequency of 1650 Hz, after hitting a specimen with a length*width*thickness of 80mm*20mm*2mm in a flexural vibration mode. Since a hot-rolled steel sheet for a vacuum train tube according to an aspect of the present disclosure may have a vibration damping ratio of 100*10 -6 or more, vibration amplification in the vacuum tube may be effectively suppressed, and damage to the vacuum train tube due to vibration may be prevented effectively.
  • a hot-rolled steel sheet for a vacuum train tube may have an electrical resistivity of 35*10 -8 ⁇ m or more, and energy efficiency may be effectively secured, when operating the vacuum train.
  • a hot-rolled steel sheet for a vacuum train tube according to an aspect of the present disclosure has a yield ratio of 0.8 or less, and a yield ratio difference ( ⁇ YR) in each direction, defined by the following relational expression 6, may be 10% or less.
  • ⁇ YR YR RD ⁇ YR TD * 100 / YR RD
  • YR RD is a yield ratio in a direction, parallel to a rolling direction of the hot-rolled steel sheet
  • YR TD is a yield ratio in a direction, perpendicular to the rolling direction of the hot-rolled steel sheet
  • YR RD - YR TD is an absolute value of a difference between the yield ratio (YR RD ) in a direction, parallel to the rolling direction and the yield ratio (YR TD ) in a direction, perpendicular to the rolling direction.
  • a Charpy impact energy of the welded portion at - 20°C may be 27 J or more, and a fraction of an M-A phase included in the welded portion may be 5 area% or less (including 0%) .
  • a preferable fraction of the M-A phase of the welded portion may be 3 area% or less, and a more preferable fraction of the M-A phase of the welded portion may be 1 area% or less.
  • the welded portion may be a position 1 mm away from a fusion line, and may be interpreted to include both a weld metal portion and a heat-affected zone (HAZ).
  • FIG. 1 is a micrograph observing a welded portion formed by welding a base material containing 1.5 wt% of silicon (Si) using a welding material not containing silicon (Si), and FIG.
  • FIG. 2 is a micrograph observing a welded portion formed by welding a base material containing 2.0 wt% of silicon (Si) using a welding material containing 0.3 wt% of silicon (Si).
  • a large amount of white portion (M-A phase) is observed at a grain boundary, while in FIG. 1 , the M-A phase is not observed.
  • a hot-rolled steel sheet having properties suitable for a vacuum train tube due to excellent yield strength, yield ratio, material anisotropy, base material low-temperature toughness, vibration damping ratio, electrical resistivity, and welded portion low-temperature toughness.
  • a thickness of a hot-rolled steel sheet for a vacuum train tube according to an aspect of the present disclosure is not particularly limited, but may be 10 mm or more to comply with the trend toward larger diameters of a vacuum train tube.
  • a method for manufacturing a hot-rolled steel sheet for a vacuum train tube includes heating a slab to a heating temperature (T 1 ) of 1100°C to 1300°C, wherein the slab includes, by weight, carbon (C): 0.03 to 0.11%, silicon (Si): 1.0 to 2.0%, manganese (Mn): 1.2 to 2.2%, a balance of Fe, and inevitable impurities; hot-rolling the heated slab at a finish rolling temperature (T 2 ) of 900°C to 1000°C to provide a hot-rolled steel sheet; and coiling the hot-rolled steel sheet at a coiling temperature (T 3 ) of 600°C to 700°C, wherein the finish rolling temperature (T 2 ) and the coiling temperature (T 3 ) satisfy the following relational expression 7: 10 ⁇ -101.9 + 0.103*[T 2 ] + 0.0339*[T 3 ] - 61.9* [C] - 190.2*[Nb] ⁇ 20
  • [T 2 ] and [T 3 ] are the finish rolling temperature (T 2 , °C) and the coiling temperature (T 3 , °C), [C] and [Nb] are an amount of carbon (C) and an amount of niobium (Nb), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • a steel slab having a predetermined alloy composition may be prepared. Since the steel slab of the present disclosure has an alloy composition corresponding to the above-described hot-rolled steel sheet, description of the alloy composition of the steel slab may be replaced with the description of the alloy composition of the above-described hot-rolled steel sheet.
  • the prepared steel slab may be heated to a heating temperature (T 1 ) of 1100°C to 1300°C.
  • T 1 a heating temperature of 1100°C to 1300°C.
  • the steel slab may be heated in a temperature range of 1100°C or higher.
  • a preferred heating temperature of the steel slab may be 1200°C or more.
  • a more preferred heating temperature of the steel slab may be 1250°C or higher.
  • the present disclosure may limit the heating temperature of the steel slab to 1300°C or lower.
  • a hot-rolled steel sheet may be provided by hot-rolling the heated steel slab at a finish rolling temperature (T 2 ) of 900°C to 1000°C.
  • the hot-rolled steel sheet provided by hot-rolling of the present disclosure may have a thickness of 10 mm or more.
  • An important process factor during hot-rolling may be a finishing delivery temperature (FDT), which may be a temperature in ending the rolling. This may be because the grain size of the final microstructure may be controlled depending on the finishing rolling temperature. Since the present disclosure seeks to control the final microstructure to a level above a certain size, hot-rolling may be performed at a finish rolling temperature of 900°C or higher. A preferable finish rolling temperature is 930°C or higher, and a more preferable finish rolling temperature is 950°C. When the finish rolling temperature is excessively high, the final microstructure may become excessively coarse. Therefore, the present disclosure may limit an upper limit of the finish rolling temperature to 1000°C.
  • the hot-rolled steel sheet provided by hot-rolling may be coiled at a coiling temperature (T 3 ) of 600°C to 700°C, after undergoing water cooling. Since the present disclosure seeks to implement a composite structure of ferrite and pearlite as a final structure, coiling may be performed in a temperature range of 600°C or higher. Since the present disclosure seeks to realize a final microstructure of a certain size or more, it is more preferable to coil at a temperature range of 650°C or higher. When a temperature of the coiling is excessively high, a coarse microstructure may be formed or surface quality may deteriorate. Therefore, the present disclosure may limit an upper limit of the coiling temperature to 700°C.
  • the inventor of the present disclosure has conducted in-depth research on technical means for controlling a particle size of the final microstructure.
  • the heating temperature (T 1 ) during heating the steel slab, the finish rolling temperature (T 2 ) during hot-rolling, and the coiling temperature (T 3 ) during coiling of the hot-rolled steel sheet should be independently controlled to satisfy a certain range, but also the finish rolling temperature (T 2 ) and the coiling temperature (T 3 ) should be controlled independently within a certain range in conjunction with each other, the relational expression 7 below was then derived. 10 ⁇ -101.9 + 0.103*[T 2 ] + 0.0339*[T 3 ] - 61.9* [C] - 190.2*[Nb] ⁇ 20
  • [T 2 ] and [T 3 ] are the finish rolling temperature (T 2 , °C) and the coiling temperature (T 3 , °C), [C] and [Nb] are an amount of carbon (C) and an amount of niobium (Nb), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • a method for manufacturing a hot-rolled steel sheet for a vacuum train tube includes not only heating a slab to a heating temperature (T 1 ) of 1100°C to 1300°C, hot-rolling at a finish rolling temperature (T 2 ) of 900°C to 1000°C, and coiling the hot-rolled steel sheet at a coiling temperature (T 3 ) of 600°C to 700°C, but also controlling process conditions such that the finish rolling temperature (T 2 ) and the coiling temperature (T 3 ) satisfy relational expression 7. Therefore, a desired microstructure of the hot-rolled steel sheets may be effectively realized.
  • the hot-rolled steel sheet manufactured by the above-described manufacturing method may satisfy any one or more of the following relational expressions 1 to 5. 7 ⁇ D F / A F ⁇ 20
  • D F means an average particle size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
  • a F means an average aspect ratio of ferrite. 355 ⁇ 11 + 394 * D F ⁇ 0.5 + 448 * C + 94 * Si + 69 * Mn 100 ⁇ 186 - 240*D F (-0.5) - 121*[C] - 13.2*[Si] + 13.7*[Mn] 27 ⁇ 476 ⁇ 95.22 * ln D F ⁇ 220 * C ⁇ 88 * Si 35 ⁇ 9.5 + 5.2 * C + 5.8 * Mn + 13.1 * Si
  • D F means an average particle size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
  • a F means an average aspect ratio of ferrite
  • D F is an average particle size (pm) of ferrite included in the hot-rolled steel sheet
  • [C], [Si], and [Mn] are an amount of carbon (C), an amount of silicon (Si), and an amount of manganese (Mn), included in the hot-rolled steel sheet (wt%), and, when a component thereamong is not included, brackets including the component are substituted with zero (0).
  • the hot-rolled steel sheet manufactured by the above-described manufacturing method may satisfy a yield strength of 350 MPa or more, a Charpy impact energy at -20°C of 27 J or more, and a vibration damping ratio of 100*10 -6 or more.
  • the vibration damping ratio refers to a vibration damping ratio measured at a frequency of 1650 Hz, after preparing a specimen with a length*width*thickness of 80mm*20mm*2mm in a flexural vibration mode.
  • the hot-rolled steel sheet manufactured by the above-described manufacturing method may satisfy an electrical resistivity of 35*10 -8 ⁇ m or more, a yield ratio of 0.8 or less, and a yield ratio difference ( ⁇ YR) in each direction of 10% or less.
  • the yield ratio difference ( ⁇ YR) for each direction may be defined as relational expression 6 below.
  • YR RD is a yield ratio in a direction, parallel to a rolling direction of the hot-rolled steel sheet
  • YR TD is a yield ratio in a direction, perpendicular to the rolling direction of the hot-rolled steel sheet
  • YR RD - YR TD is an absolute value of a difference between the yield ratio (YR RD ) in a direction, parallel to the rolling direction and the yield ratio (YR TD ) in a direction, perpendicular to the rolling direction.
  • a Charpy impact energy of the welded portion at -20°C may be 27 J or more, and a fraction of an M-A phase included in the welded portion may be 5 area% or less (including 0%).
  • the welded portion may be a position 1 mm away from a fusion line.
  • Microstructures and mechanical properties of each specimen were analyzed and listed in Table 3, and whether Relational expressions 1 to 5 of each specimen were satisfied may be also listed in Table 3.
  • the microstructures were measured using an optical microscope at 500x magnification after etching each specimen using a Nital etching method.
  • a grain size of ferrite was measured according to ASTM E112.
  • An aspect ratio of ferrite was measured using a length of the longest side of a grain and a length of a side, perpendicular thereto.
  • FIG. 3 is an optical micrograph used to observe a microstructure of specimen 1.
  • the mechanical properties were measured according to KS B 0802 and KS B 0810, and measured yield strength and yield ratio were listed in Table 4.
  • a vibration damping ratio was measured at room temperature using IMCE's RFDA LTV800 after preparing a specimen with length*width*thickness of 80*20*2 mm. After hitting in a flexural vibration mode, the vibration damping ratio in a 1650 Hz region corresponding to a 1 st mode among vibration modes of the specimen was measured and analyzed, and results therefrom were listed in Table 4. Electrical resistivity was measured according to KS C IEC 60404, and values thereof were listed in Table 4.
  • Submerged arc welding was performed on each specimen using a welding material containing C: 0.052 wt%, Mn: 1.53 wt%, Ni: 1.3 wt%, Mo: 0.135 wt%, a remaining Fe, and other inevitable impurities.
  • a heat input of 20 kJ/cm 2 was applied to the inside, and a heat input of 22 kJ/cm 2 was applied to the outside.
  • a -20°C Charpy impact toughness of the welded portion was measured according to KS B 0810, and results therefrom were listed in Table 4.
  • first etching was performed using a solution of 5 g of EDTA and 0.5 g of NaF dissolved in 100 ml of distilled water
  • second etching was then performed using a solution of 25 g of NaOH and 5 g of picric acid dissolved in 100 ml of distilled water.
  • the second etching was performed, and an M-A phase fraction was measured according to ASTM E 562.
  • ASTM E 562 [Table 3] Specim en No.
  • specimens that satisfy the alloy composition, process conditions, and Relational expressions 1 to 5 of the present disclosure satisfied a yield strength of 350 MPa or more, a vibration damping ratio of 100*10 -6 or more, a yield ratio of 0.8 or less, a yield ratio difference ( ⁇ YR) in each direction of 10% or less, and an electrical resistivity of 35*10-8 ⁇ m or more, and a Charpy impact energy at -20°C of the welded portion satisfied 27 J or more. It can be seen that specimens not satisfying one or more of the conditions limited by the present disclosure did not simultaneously secure the desired properties.
  • FIG. 4 is an optical micrograph of EN-S355 taken using an optical microscope.
  • a hot-rolled steel sheet having excellent yield strength, yield ratio, vibration damping ratio, and low-temperature toughness, and low anisotropy of the yield ratio, and having properties suitable for a vacuum train tube, and a manufacturing method thereof.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
EP22911814.6A 2021-12-20 2022-12-19 Warmgewalzter stahl für hyperrohre und herstellungsverfahren dafür Pending EP4455338A4 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1020210182580A KR20230093722A (ko) 2021-12-20 2021-12-20 진공열차 튜브용 열연강판 및 그 제조방법
PCT/KR2022/020722 WO2023121181A1 (ko) 2021-12-20 2022-12-19 진공열차 튜브용 열연강판 및 그 제조방법

Publications (2)

Publication Number Publication Date
EP4455338A1 true EP4455338A1 (de) 2024-10-30
EP4455338A4 EP4455338A4 (de) 2026-01-14

Family

ID=86903363

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22911814.6A Pending EP4455338A4 (de) 2021-12-20 2022-12-19 Warmgewalzter stahl für hyperrohre und herstellungsverfahren dafür

Country Status (5)

Country Link
US (1) US20250051892A1 (de)
EP (1) EP4455338A4 (de)
KR (1) KR20230093722A (de)
CA (1) CA3241605A1 (de)
WO (1) WO2023121181A1 (de)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007291511A (ja) * 2006-03-29 2007-11-08 Jfe Steel Kk 靭性に優れた高張力厚鋼板およびその製造方法
JP5018934B2 (ja) * 2010-06-29 2012-09-05 Ｊｆｅスチール株式会社 加工性に優れた高強度鋼板およびその製造方法
JP5397437B2 (ja) * 2011-08-31 2014-01-22 Ｊｆｅスチール株式会社 加工性と材質安定性に優れた冷延鋼板用熱延鋼板、溶融亜鉛めっき鋼板用熱延鋼板およびその製造方法
JP5316634B2 (ja) * 2011-12-19 2013-10-16 Ｊｆｅスチール株式会社 加工性に優れた高強度鋼板およびその製造方法
KR102106353B1 (ko) 2019-07-24 2020-05-04 태산엔지니어링 주식회사 초고강도 레진 모르타르 조성물 및 이를 이용한 수중 구조물 및 하이퍼루프용 튜브의 제작 시공 방법
JP7303435B2 (ja) * 2019-08-20 2023-07-05 日本製鉄株式会社 熱延鋼板およびその製造方法
KR102348664B1 (ko) * 2019-12-18 2022-01-06 주식회사 포스코 진공튜브용 강재 및 그 제조방법
CN117897513A (zh) * 2021-08-31 2024-04-16 浦项股份有限公司 真空列车管用热轧钢板及其制造方法

Also Published As

Publication number Publication date
US20250051892A1 (en) 2025-02-13
CA3241605A1 (en) 2023-06-29
WO2023121181A1 (ko) 2023-06-29
EP4455338A4 (de) 2026-01-14
KR20230093722A (ko) 2023-06-27

Similar Documents

Publication Publication Date Title
EP2949772B1 (de) Heissgewalztes stahlblech und verfahren zur herstellung davon
KR101444646B1 (ko) 어레스트성이 우수한 고강도 후강판
EP2811046B1 (de) Warmgewalztes stahlblech für eine generatorrippe und herstellungsverfahren dafür
WO2003006699A1 (en) High strength steel pipe having strength higher than that of api x65 grade
KR20140138933A (ko) 내변형 시효 특성이 우수한 저항복비 고강도 강판 및 그 제조 방법 그리고 그것을 사용한 고강도 용접 강관
JP6455650B1 (ja) トーションビーム用アズロール電縫鋼管
CN102884217A (zh) 落锤冲击特性优异的高强度厚钢板
EP4455338A1 (de) Warmgewalzter stahl für hyperrohre und herstellungsverfahren dafür
KR20190111920A (ko) 압연 h형강 및 그 제조 방법
EP4397780A1 (de) Warmgewalztes stahlblech für hyperrohr und herstellungsverfahren dafür
EP4261308A1 (de) Warmgewalztes stahlblech für hyperzugrohr und herstellungsverfahren dafür
JP7701464B2 (ja) 真空列車チューブ用熱延鋼板及びその製造方法
JP2004232091A (ja) 耐地震特性に優れた構造用鋼材の製造方法
KR20240098928A (ko) 강판 및 그 제조방법
KR20240098927A (ko) 강판 및 그 제조방법
KR20240098878A (ko) 진공열차 튜브용 열연강판 및 그 제조 방법
CN117015628B (en) Hot rolled steel sheet for vacuum train pipeline and method for manufacturing same
KR20250090684A (ko) 진공 열차 튜브용 열연 강판
EP4640886A1 (de) Warmgewalztes stahlblech und herstellungsverfahren dafür
KR20120044121A (ko) 저항복비를 갖는 고강도 ａｐｉ 열연강판 및 그 제조 방법
JPH09256103A (ja) 熱間成形後に低降伏比の鋼板部材が得られる熱延鋼板及びその熱延鋼板部材
KR100782748B1 (ko) 초미세 페라이트 조직을 갖는 강 및 그 제조 방법
JPH08134609A (ja) 溶接熱影響部軟化の小さい高強度高Ｍｎ非磁性鋼板

Legal Events

Date Code Title Description
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: 20240619

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 ME MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
A4 Supplementary search report drawn up and despatched

Effective date: 20251216

RIC1 Information provided on ipc code assigned before grant

Ipc: C22C 38/04 20060101AFI20251210BHEP

Ipc: C22C 38/02 20060101ALI20251210BHEP

Ipc: C22C 38/14 20060101ALI20251210BHEP

Ipc: C22C 38/12 20060101ALI20251210BHEP

Ipc: C22C 38/38 20060101ALI20251210BHEP

Ipc: C22C 38/34 20060101ALI20251210BHEP

Ipc: C21D 8/02 20060101ALI20251210BHEP

Ipc: C21D 9/46 20060101ALI20251210BHEP

Ipc: C22C 38/08 20060101ALI20251210BHEP

Ipc: C22C 38/16 20060101ALI20251210BHEP