EP2520683A2 - Tôle d'acier à haute résistance présentant une excellente résistance aux fissures fragiles et procédé de fabrication de celle-ci - Google Patents

Tôle d'acier à haute résistance présentant une excellente résistance aux fissures fragiles et procédé de fabrication de celle-ci Download PDF

Info

Publication number
EP2520683A2
EP2520683A2 EP10841181A EP10841181A EP2520683A2 EP 2520683 A2 EP2520683 A2 EP 2520683A2 EP 10841181 A EP10841181 A EP 10841181A EP 10841181 A EP10841181 A EP 10841181A EP 2520683 A2 EP2520683 A2 EP 2520683A2
Authority
EP
European Patent Office
Prior art keywords
steel sheet
less
brittle crack
crack initiation
heat affected
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.)
Granted
Application number
EP10841181A
Other languages
German (de)
English (en)
Other versions
EP2520683A4 (fr
EP2520683B1 (fr
Inventor
Sang-Ho Kim
Ki-Hyun Bang
In-Shik Suh
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 EP2520683A2 publication Critical patent/EP2520683A2/fr
Publication of EP2520683A4 publication Critical patent/EP2520683A4/fr
Application granted granted Critical
Publication of EP2520683B1 publication Critical patent/EP2520683B1/fr
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • C22C38/04—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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
    • B21B3/02—Rolling special iron alloys, e.g. stainless steel
    • 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
    • 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
    • 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
    • C22C38/08—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
    • C22C38/12—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
    • 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
    • C21D2201/00—Treatment for obtaining particular effects
    • C21D2201/05—Grain orientation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints

Definitions

  • the present invention relates to a high-strength steel sheet used in offshore and building structures, and more particularly, to a high-strength steel sheet having excellent resistance to brittle crack initiation in a parent material and in a weld heat affected zone (HAZ) and a method of manufacturing the same.
  • HZ weld heat affected zone
  • a crack tip opening displacement (CTOD) test based on fracture mechanics is mainly used as a method of evaluating resistance to brittle crack initiation at low temperatures.
  • the CTOD test has mainly been used to evaluate resistance to brittle crack initiation in a weld heat affected zone so far.
  • an impact test instead of the CTOD test has been used for a parent material zone.
  • high-strength thick steel sheets having a thickness of 50 mm or more are mainly used in offshore structures built in extreme cold regions such as Sakhalin and the Arctic Ocean in consideration of collisions with icebergs, and in addition, there is a possibility that brittle cracks may be generated from fatigue cracks under specific conditions after fatigue cracks initiated in a weld zone propagate into a parent material zone along a direction of applied cyclic stress, a high level of resistance to brittle crack initiation is required for the parent material zone as well as the weld heat affected zone.
  • Korean Patent Application Laid-Open Publication No. 2002-0028203 discloses a method of preventing the generation of brittle fractures in weld heat affected zones by adding magnesium (Mg) to inhibit grain coarsening generated near a fusion line during welding.
  • Mg magnesium
  • this patent guarantees the prevention of brittle fractures at a temperature of -10°C or more, resistance to brittle fractures at a low temperature such as -40°C may not be guaranteed.
  • Korean Patent Application Laid-Open Publication No. 2008-0067957 discloses a technique of preventing a rapid decrease in toughness generated in weld heat affected zones by limiting aluminum (Al) or niobium (Nb) below a predetermined limit and securing resistance to brittle crack initiation of weld heat affected zones even at a low temperature of -40°C by using manganese (Mn) having a low effect on the toughness of the weld heat affected zone.
  • Al aluminum
  • Nb niobium
  • Mn manganese
  • Korean Patent Application Laid-Open Publication No. 2006-0090287 discloses a method of manufacturing steels having excellent resistance to brittle crack initiation in a parent material zone and a weld heat affected zone at a low temperature of -40°C, as a technique for securing physical properties of the steel sheet by reducing a carbon (C) content to inhibit the formation of martensitic islands and using precipitation hardening due to copper (Cu) precipitates generated by the addition of 0.8% or more of Cu.
  • C carbon
  • Cu copper
  • An aspect of the present invention provides a high-strength steel sheet having excellent resistance to brittle crack initiation able to inhibit initiation of brittle cracks at low temperatures in both a parent material zone and a weld heat affected zone (HAZ) and having a yield strength of 420 MPa or more, and a method of manufacturing the high-strength steel sheet.
  • HZ weld heat affected zone
  • a high-strength steel sheet having excellent resistance to brittle crack initiation including: 0.02 wt% to 0.06 wt% of C (carbon); 0.1 wt% or less of Si (silicon); 1.5 wt% to 2.0 wt% of Mn (manganese); 0.012 wt% or less of P (phosphorous); 0.003 wt% or less of S (sulfur); 0.5 wt% to 1.5 wt% of Ni (nickel); 0.003 wt% to 0.015 wt% of Al (aluminum); 0.005 wt% to 0.02 wt% of Ti (titanium); 0.005 wt% to 0.015 wt% of Nb (niobium); 0.002 wt% to 0.006 wt% of N (nitrogen); and Fe (iron) as well as unavoidable impurities as a remainder, wherein a value of C+0.5
  • a method of manufacturing a high-strength steel sheet having excellent resistance to brittle crack initiation including: heating a steel slab satisfying the foregoing composition range within a temperature range of 1000°C to 1100°C; rough rolling the heated slab at a cumulative reduction rate of 40% or more and a temperature of 950°C or more; finish rolling within a temperature range of 700°C to 800°C after the rough rolling; and cooling the rolled steel sheet.
  • a high-strength steel sheet having a yield strength of 420 MPa or more and simultaneously having excellent resistances to brittle crack initiation at low temperatures of -60°C to -40°C in a parent material and a weld heat affected zone, respectively, and a method of manufacturing the high-strength steel sheet may be provided.
  • the foregoing thick steel sheet may be used in offshore structures, building structures, ships, tankers or the like, operating in extreme environments.
  • FIG. 1 is a graph showing the results of crack tip opening displacement (CTOD) tests for a weld heat affected zone according to a value of C+0.5Si-0.1Ni+6Al+3Nb; and
  • FIG. 2 is a graph showing the results of CTOD tests for a parent material zone according to an effective grain size.
  • the present inventors have recognized that a martensitic island structure generated in a weld heat affected zone is a cause of brittle cracks generated at low temperatures in the weld heat affected zone.
  • CTOD crack tip opening displacement
  • the present inventors found that brittle fractures mainly occur at a center of the sheet in a thickness direction of the steel sheet and brittle cracks are microstructurally initiated at relatively coarse grains among grains in the center of the sheet in the thickness direction, and as a result of in-depth research into a method of inhibiting the brittle cracks, the present inventors completed the present invention.
  • composition range of the present invention will be described in detail, in terms of weight percentage, (hereinafter, wt%).
  • C is an important alloying element for constituting martensitic islands generated in a weld heat affected zone to initiate brittle fracture, it is essential to primarily limit a content of C in order to inhibit formation of martensitic islands.
  • a content of C is greater than 0.06%, a target of the present invention may not be achieved due to the insufficient inhibition of martensitic islands. Therefore, an upper limit of C may be limited to 0.06%.
  • a lower limit thereof may be 0.02%.
  • Si is an element required for increasing tensile strength of a parent material zone and deoxidization of steel.
  • Si greatly contributes to the formation of martensitic islands by preventing the decomposition of untransformed austenites into ferrites and cementites when the untransformed austenites formed by a weld heat cycle are cooled to form a final structure and thus, greatly decreases CTOD toughness in a weld heat affected zone. Therefore, an amount of added Si may be limited to 0.1% or less.
  • Mn is a useful element for securing strength
  • Mn must be added in an amount of 1.5% or more in order to secure the strength of the steel sheet.
  • an upper limit of Mn may be limited to 2.0%.
  • P and S are elements generating grain boundary embrittlement in a weld heat affected zone, P and S are required to be minimized. However, since there are difficulties in decreasing P and S to a very low level in a steelmaking process, contents of P and S are limited to 0.012% or less and 0.003% or less, respectively.
  • Ni increases hardenability to promote formation of martensitic islands.
  • an effect of reinforcing toughness of a matrix structure is greater than the foregoing effect, Ni may have an effect of rather improving toughness of a weld heat affected zone different from other alloying elements.
  • the effect of improving toughness of the matrix phase by Ni is also exhibited in a parent material zone, it is also effective in reinforcing toughness of the parent material zone.
  • Ni is required to be added in an amount of 0.5% or more.
  • an upper limit thereof may be limited to 1.5%.
  • Al is an element contributing to formation of martensitic islands by preventing formation of ferrites and cementites from untransformed austenites during a weld heat cycle. Since Al greatly decreases toughness of a weld heat affected zone when added in an amount of greater than 0.015%, an upper limit thereof may be limited to 0.015%. However, Al is a very effective element for the deoxidization of steel. When a content of Al is also too low in a state in which the Si content in the present invention is limited to 0.1% or less, deoxidization of steel may be insufficiently performed, and thus, cleanliness of the steel may be greatly deteriorated. Therefore, Al may be added in an amount of 0.003% or more.
  • Ti prevents grain coarsening generated near a weld fusion line by forming fine nitrides in combination with nitrogen (N) and thus, improves toughness of a weld heat affected zone.
  • N nitrogen
  • Ti may be added in an amount of 0.005% or more.
  • Ti carbides may be formed together with the Ti nitrides and hardnesses of a parent material zone and the weld heat affected zone may increase due to a precipitate hardening effect of the Ti carbides, and thus, the possibility of brittle crack initiation may be increased. Therefore, an upper limit of Ti may be limited to 0.02%.
  • Nb is an alloying element that decreases resistance to brittle fractures in a weld heat affected zone when added.
  • Nb greatly contributes to refine a structure during a controlled rolling-accelerated cooling process
  • Nb is an important element for increasing resistance to brittle fractures in a parent material zone.
  • an effective grain size of 30 ⁇ m or less required in the present invention may be difficult to obtain unless refinement of the structure by Nb is accompanied, even in the case in which the controlled rolling-accelerated cooling process is performed. Therefore, Nb may be added in an amount of 0.005% or more in order to secure the resistance to brittle fractures in the parent material zone required in the present invention.
  • an upper limit thereof may be limited to 0.015%.
  • N combines with Ti to form TiN particles and thus, prevents grain coarsening near a weld fusion line. Therefore, N may be required to be included in an amount of 0.002% or more in order to obtain the foregoing effect.
  • an upper limit of N may be limited to 0.006%.
  • Cu copper
  • a content of Cu may be 0.35% or less.
  • Cu is an alloying element that may secure strength of the steel sheet as well as being relatively less harmful to the toughness of a weld heat affected zone.
  • the strength of the steel sheet excessively increases when Cu is excessively added and thus, stable CTOD toughness may not be obtained in a parent material zone and Cu cracks may be initiated on surfaces of slab and steel sheet. Therefore, an upper limit of Cu may be limited to 0.35%.
  • Fe and unavoidable impurities are included as a remainder.
  • a value of C+0.5Si-0.1Ni+6Al+3Nb in the composition may be 0.1% or less.
  • the present inventors deduced a method of minimizing the generation of martensitic islands in the weld heat affected zone under a low to medium heat input welding condition having a heat input range of 0.8 kJ/mm to 4.5 kJ/mm.
  • the present inventors conducted weld heat affected zone simulation experiments to simulate an intercritically reheated coarse grained heat affected zone which is known as a region, in which the largest amount of martensitic islands is formed in the weld heat affected zone.
  • the intercritically reheated coarse grained heat affected zone was simulated in such a manner that small samples having a thickness of 10 mm, a width of 10 mm, and a length of 60 mm were heated to a temperature of 1400°C and then cooled at a cooling rate of 20°C/s within a temperature range of 800°C to 500°C, and intercritically reheated and then cooled at a cooling rate of 20°C/s within a temperature range of a maximum heated temperature to 500°C.
  • Fatigue cracks were introduced at up to 50% of a width of the heat affected zone simulation samples and CTOD tests were then performed at -40°C. From the result of the tests, a correlation between the alloying elements and CTOD toughness of the weld heat affected zone was deduced and the results thereof are presented in FIG. 1 .
  • FIG. 1 illustrates a relationship between values of C+0.5Si-0.1Ni+6A1+3Nb and critical CTOD test values at -40°C obtained from the heat affected zone simulation samples. It may be understood that the lower the value of C+0.5Si-0.1Ni+6Al+3Nb is, the higher the critical CTOD value at -40°C of the weld heat affected zone is. When the value of C+0.5Si-0.1Ni+6Al+3Nb is greater than 0.2%, brittle fracture occurred in all samples. According to FIG. 1 , it may be understood that the value of C+0.5Si-0.1Ni+6Al+3Nb must be 0.1% or less in order that the critical CTOD value measured at -40°C becomes 0.25 mm or more.
  • C, Si, Al, and Nb alloying elements promote the initiation of brittle cracks in the weld heat affected zone when added, but only Ni has an opposite effect.
  • the reason for this is that the effect of reinforcing toughness of the matrix structure by Ni is greater than that of decreasing toughness by increasing martensitic islands in the weld heat affected zone as a hardening element.
  • an average circle equivalent diameter of grains having a size belong to top 5% of a minimum of 5000 or more grains defined as boundaries having a grain misorientation of 15 degrees or more measured at a center of the sheet in the thickness direction of the steel sheet by an electron back-scattered pattern (EBSP) method may be 30 ⁇ m or less.
  • the center of the sheet in the thickness direction is defined such that it is positioned within ⁇ 1 mm in a thickness direction from a position at 1/2 of the thickness of the steel sheet.
  • an image analysis method based on an optical microscopic image is used for measuring a grain size.
  • relatively accurate analysis may be possible only when a microstructure is composed of polygonal ferrites and pearlites, and an accurate measurement of grain size may be very difficult because grain boundaries are unclear in a microstructure having acicular ferrites or bainites mixed therein.
  • the present inventors used an EBSP method based on Kikuchi patterns in order to more accurately measure a grain size of the center of the sheet in the thickness direction.
  • the EBSP method has advantage in that an intergranular misorientation may be quantitatively analyzed regardless of a microstructure.
  • a boundary having a measured intergranular misorientation of 15 degrees or more is defined as a large-angle grain boundary.
  • an average circle equivalent diameter of grains (effective grains) having a size belong to top 5% of a minimum of 5000 or more grains defined as boundaries (large-angle grain boundaries) having a grain misorientation of 15 degrees or more measured at the center of the sheet in the thickness direction of the steel sheet by the EBSP method is defined as an effective grain size.
  • samples having various grain sizes were prepared from a slab having a composition of 0.05C-0.04Si-1.62Mn-0.95Ni by varying heating and rolling conditions, and CTOD tests were performed at various temperatures by using the samples and 0.25 mm critical CTOD transition temperatures were then obtained.
  • the 0.25 mm critical CTOD transition temperature is denoted as a transition temperature when the measured critical CTOD value is 0.25 mm.
  • a relationship between the effective grain size and the 0.25 mm critical CTOD transition temperature measured from each sample is shown in FIG. 2 .
  • a steel sheet having a minimum critical CTOD value of 0.25 mm or more at -60°C may be obtained when the effective grain size defined in the present invention is 30 ⁇ m or less.
  • the effective grain size is greater than 30 ⁇ m, a critical CTOD value at - 60°C of the parent material zone in the steel sheet becomes 0.25 mm or less, and thus, the target of the present invention may not be satisfied.
  • a basic microstructure of the center of the sheet in the thickness direction may include ferrite, bainite, or a composite structure thereof excluding martensite.
  • a targeted critical CTOD value may not be obtained because hardness of the martensite structure is so high even in the case of having a fine grain size that a pop-in phenomenon is facilitated at an extremely low temperature such as -60°C.
  • a critical CTOD value at -60°C of the parent material zone is 0.25 mm or more and a critical CTOD value at -40°C of the weld heat affected zone (HAZ) during welding is 0.25 mm or more, excellent low-temperature brittle crack resistance characteristics are obtained in the parent material zone as well as the weld heat affected zone.
  • a steel slab satisfying the foregoing composition is heated to within a temperature range of 1000°C to 1100°C.
  • a continuous cast slab may be used as the slab. Since a continuous casting process has a solidification rate of molten steel and a cooling rate after the solidification faster than those of an ingot process, finer TiN particles may be obtained in a material, and thus, resistance to brittle crack initiation of the parent material zone and of the weld heat affected zone may increase.
  • a heating temperature of the slab is an important factor affecting a grain size of a final structure.
  • the heating temperature of the slab is greater than 1100°C, the final structure may be insufficiently refined and TIN particles in the structure become coarse to decrease toughness of the weld heat affected zone. Therefore, an upper limit thereof may be limited to 1100°C.
  • the heating temperature of the slab is less than 1000°C, alloying elements may be insufficiently dissolved and sufficient rolling may be difficult above a recrystallization temperature. Therefore, the heating of the slab may be performed at a temperature of 1000°C or more.
  • the slab is heated and rough rolling is then performed at a cumulative reduction rate of 40% or more and a temperature of 950°C or more. Since recrystallization of austenite grains actively occurs at a temperature of 950°C or more, the grain size may decrease. Also, the reason for having a cumulative reduction rate of 40% or more is that mixed grains may be generated in the final structure because the recrystallization of austenite grains occurs insufficiently when the cumulative reduction rate is less than 40%.
  • Finish rolling may be performed within a temperature range of 700°C to 800°C.
  • the finish rolling temperature is greater than 800°C, resistance to brittle crack initiation may not be secured because refinement of a structure at the center of the sheet in the thickness direction is insufficiently completed.
  • a lower limit thereof may be limited to 700°C.
  • finish rolling may be performed at a minimum cumulative reduction rate of 40% or more in order to further refine the final structure.
  • a cooling rate and a cooling stop temperature may be in ranges of 3 °C/s to 20 °C/s and 350°C to 550°C, respectively. Since brittle crack initiation is facilitated when the strength is excessively higher than a target value, it is important not to have excessively high strength. From such a point of view, the cooling rate and the cooling stop temperature may be 20 °C/s or less and 350°C or more, respectively. However, since the strength targeted in the present invention may not be obtained when the cooling is insufficient, the cooling rate and the cooling stop temperature for this purpose may be 3 °C/s or more and 550°C or less, respectively.
  • Molten steels were prepared in a 300-ton electric furnace according to compositions presented in Table 1 and 300 mm thick slabs were prepared through a continuous casting method. As shown in Table 2, the slabs thus prepared were heated and subjected to rough rolling and finish rolling, and steels were prepared by final accelerated cooling.
  • An electron back-scattered pattern (EBSP) apparatus attached to a scanning electron microscope (SEM) was used for measuring effective grain sizes of the prepared steel sheets.
  • the magnifications used were within a range of 300 times to 500 times, a step size was 0.75 ⁇ m, and center of the sheet in the thickness directions of cross sections in rolling and thickness directions were observed.
  • a minimum of 5000 or more grains defined as boundaries having a grain misorientation of 15 degrees or more were included.
  • the effective grain sizes defined in the present invention were calculated by using software able to analyze misorientations measured by the EBSP method.
  • Fatigue cracks were generated up to 50% of a width of the samples after notches were made in the CTOD samples by electric discharge machining and CTOD tests were then performed three times for each sample at a temperature of -60°C and each sample was evaluated with a minimum value thereof.
  • Evaluations were performed in accordance with the API RP 2Z rule in order to evaluate resistances to brittle crack initiation in the weld heat affected zones of the prepared thick steel sheets.
  • Single-opening lines were made according to the API RP 2Z rule and weldings were performed at welding heat inputs of 0.8 kJ/mm and 4.5 kJ/mm by flux cored arc welding and submerged arc welding, respectively.
  • Welded samples were machined into full-thickness specimens in accordance with the BS7448 standard as in the parent material zones and fatigue cracks were introduced into coarse grain regions near weld fusion lines. CTOD tests were then performed three times for each sample at -40°C and each sample was evaluated with a minimum value thereof.
  • Inventive Examples 1 to 16 corresponding to the composition and manufacturing method of the present invention, effective grain sizes defined in the present invention were 30 ⁇ m or less, critical CTOD values of the parent material zones evaluated at -60°C were 0.25 mm or more, and minimum CTOD values at -40°C of the weld heat affected zones under low and medium heat input conditions were also 0.25 mm or more, and thus, very good resistances to brittle crack initiation were obtained.
  • a CTOD value of the weld heat affected zone was not greater than 0.25 mm because a value of C+0.5Si-0.1Ni+6Al+3Nb exceeded 0.1%.
  • Si and Al in Comparative Example 2 did not satisfy the scope of the present invention and the value of C+0.5Si-0.1Ni+6Al+3Nb was also high at 0.199%, and thus, CTOD characteristics of the weld heat affected zone at -40°C was very poor.

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)
EP10841181.0A 2009-12-28 2010-12-22 Tôle d'acier à haute résistance présentant une excellente résistance aux fissures fragiles et procédé de fabrication de celle-ci Active EP2520683B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1020090131740A KR101360737B1 (ko) 2009-12-28 2009-12-28 취성 균열 발생 저항성이 우수한 고강도 강판 및 그 제조방법
PCT/KR2010/009222 WO2011081349A2 (fr) 2009-12-28 2010-12-22 Tôle d'acier à haute résistance présentant une excellente résistance aux fissures fragiles et procédé de fabrication de celle-ci

Publications (3)

Publication Number Publication Date
EP2520683A2 true EP2520683A2 (fr) 2012-11-07
EP2520683A4 EP2520683A4 (fr) 2015-03-11
EP2520683B1 EP2520683B1 (fr) 2016-11-30

Family

ID=44226970

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10841181.0A Active EP2520683B1 (fr) 2009-12-28 2010-12-22 Tôle d'acier à haute résistance présentant une excellente résistance aux fissures fragiles et procédé de fabrication de celle-ci

Country Status (4)

Country Link
EP (1) EP2520683B1 (fr)
KR (1) KR101360737B1 (fr)
CN (1) CN102753719B (fr)
WO (1) WO2011081349A2 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103695807A (zh) * 2013-12-13 2014-04-02 莱芜钢铁集团有限公司 止裂性优良的超高强x100管线钢板及其制备方法
WO2017145651A1 (fr) * 2016-02-24 2017-08-31 Ｊｆｅスチール株式会社 Tôle d'acier ultra-épaisse de haute résistance, ayant d'excellentes caractéristiques d'arrêt de la propagation des fissures fragiles et son procédé de fabrication
JP2018503744A (ja) * 2014-12-24 2018-02-08 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた高強度鋼材及びその製造方法
JP2018504520A (ja) * 2014-12-24 2018-02-15 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた高強度鋼材及びその製造方法
JP2018504523A (ja) * 2014-12-24 2018-02-15 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた高強度鋼材及びその製造方法
JP2018504524A (ja) * 2014-12-24 2018-02-15 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた構造用極厚鋼材及びその製造方法
JP2020509165A (ja) * 2016-12-22 2020-03-26 ポスコＰｏｓｃｏ 表面部ｎｒｌ−ｄｗｔ物性に優れる極厚物鋼材及びその製造方法
CN113166888A (zh) * 2018-11-30 2021-07-23 株式会社Posco 脆性裂纹止裂特性优异的超厚钢及其制造方法

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103882312B (zh) * 2014-03-04 2016-04-27 南京钢铁股份有限公司 低成本高韧性-140℃低温用钢板的制造方法
EP3095889A1 (fr) 2015-05-22 2016-11-23 Outokumpu Oyj Procédé de fabrication d'un composant en acier austénitique
SI3117922T1 (en) 2015-07-16 2018-07-31 Outokumpu Oyj A method for producing a component of TWIP or TRIP / TWIP austenitic steel
KR101726082B1 (ko) * 2015-12-04 2017-04-12 주식회사 포스코 취성균열전파 저항성 및 용접부 취성균열개시 저항성이 우수한 고강도 강재 및 그 제조방법
KR101736611B1 (ko) * 2015-12-04 2017-05-17 주식회사 포스코 취성균열전파 저항성 및 용접부 취성균열개시 저항성이 우수한 고강도 강재 및 그 제조방법
KR101758520B1 (ko) * 2015-12-23 2017-07-17 주식회사 포스코 열간 저항성이 우수한 고강도 구조용 강판 및 그 제조방법
KR102220739B1 (ko) * 2018-12-19 2021-03-02 주식회사 포스코 두께 중심부 인성이 우수한 극후물 강판의 제조방법

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4341396B2 (ja) * 2003-03-27 2009-10-07 Ｊｆｅスチール株式会社 低温靱性および溶接性に優れた高強度電縫管用熱延鋼帯
WO2005052205A1 (fr) * 2003-11-27 2005-06-09 Sumitomo Metal Industries, Ltd. Acier a haute resistance mecanique presentant une zone soudee d'une durete excellente et une structure offshore associee
CN101153370B (zh) * 2006-09-27 2012-06-13 鞍钢股份有限公司 一种可大线能量焊接的低合金高强度钢板及其制造方法
EP2060643B1 (fr) 2006-12-20 2012-04-18 Nippon Steel Corporation Acier excellant par sa dureté dans les zones affectées par la chaleur de la soudure
JP4934505B2 (ja) * 2007-05-29 2012-05-16 株式会社神戸製鋼所 疲労亀裂進展抑制特性および脆性破壊抑制特性に優れた鋼板
KR20110125277A (ko) * 2007-12-07 2011-11-18 신닛뽄세이테쯔 카부시키카이샤 용접열 영향부의 ｃｔｏｄ 특성이 우수한 강 및 그 제조 방법
KR100985298B1 (ko) * 2008-05-27 2010-10-04 주식회사 포스코 리징 저항성이 우수한 저비중 고강도 열연 강판, 냉연강판, 아연도금 강판 및 이들의 제조방법

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103695807A (zh) * 2013-12-13 2014-04-02 莱芜钢铁集团有限公司 止裂性优良的超高强x100管线钢板及其制备方法
CN103695807B (zh) * 2013-12-13 2016-01-20 莱芜钢铁集团有限公司 止裂性优良的超高强x100管线钢板及其制备方法
JP2018504524A (ja) * 2014-12-24 2018-02-15 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた構造用極厚鋼材及びその製造方法
JP2018503744A (ja) * 2014-12-24 2018-02-08 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた高強度鋼材及びその製造方法
JP2018504520A (ja) * 2014-12-24 2018-02-15 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた高強度鋼材及びその製造方法
JP2018504523A (ja) * 2014-12-24 2018-02-15 ポスコＰｏｓｃｏ 脆性亀裂伝播抵抗性に優れた高強度鋼材及びその製造方法
US10822671B2 (en) 2014-12-24 2020-11-03 Posco High-strength steel having superior brittle crack arrestability, and production method therefor
US10883159B2 (en) 2014-12-24 2021-01-05 Posco High-strength steel having superior brittle crack arrestability, and production method therefor
WO2017145651A1 (fr) * 2016-02-24 2017-08-31 Ｊｆｅスチール株式会社 Tôle d'acier ultra-épaisse de haute résistance, ayant d'excellentes caractéristiques d'arrêt de la propagation des fissures fragiles et son procédé de fabrication
JPWO2017145651A1 (ja) * 2016-02-24 2018-03-08 Ｊｆｅスチール株式会社 脆性き裂伝播停止特性に優れた高強度極厚鋼板およびその製造方法
JP2020509165A (ja) * 2016-12-22 2020-03-26 ポスコＰｏｓｃｏ 表面部ｎｒｌ−ｄｗｔ物性に優れる極厚物鋼材及びその製造方法
CN113166888A (zh) * 2018-11-30 2021-07-23 株式会社Posco 脆性裂纹止裂特性优异的超厚钢及其制造方法
EP3889295A4 (fr) * 2018-11-30 2022-03-09 Posco Acier ultra-épais présentant une excellente résistance aux fissures fragiles et son procédé de fabrication
US12338515B2 (en) 2018-11-30 2025-06-24 Posco Co., Ltd Ultra-thick steel excellent in brittle crack arrestability and manufacturing method therefor

Also Published As

Publication number Publication date
EP2520683A4 (fr) 2015-03-11
WO2011081349A2 (fr) 2011-07-07
CN102753719B (zh) 2015-08-19
WO2011081349A3 (fr) 2011-11-10
EP2520683B1 (fr) 2016-11-30
CN102753719A (zh) 2012-10-24
KR101360737B1 (ko) 2014-02-07
KR20110075321A (ko) 2011-07-06

Similar Documents

Publication Publication Date Title
EP2520683B1 (fr) Tôle d'acier à haute résistance présentant une excellente résistance aux fissures fragiles et procédé de fabrication de celle-ci
JP5924058B2 (ja) 溶接熱影響部の低温靭性に優れた高張力鋼板およびその製造方法
EP2434027B1 (fr) Matériau en acier apte au soudage avec un apport calorifique élevé
KR101312211B1 (ko) Ni 첨가 강판 및 그 제조 방법
KR101635008B1 (ko) 용접 열영향부 ctod 특성이 우수한 후육 고장력강 및 그의 제조 방법
US10023946B2 (en) Thick steel sheet having excellent CTOD properties in multilayer welded joints, and manufacturing method for thick steel sheet
KR20140117560A (ko) 용접 열 영향부의 저온 인성이 우수한 고장력 강판 및 그 제조 방법
JP2011214120A (ja) 低温焼戻脆化割れ性に優れた耐摩耗鋼板
KR20210099627A (ko) 고강도 강 제품 및 그 제조 방법
WO2009123076A1 (fr) Matériau d'acier réfractaire avec un joint soudé présentant une excellente insensibilité à la fragilisation par rechauffage et une excellente ténacité et son procédé de fabrication
KR100697905B1 (ko) 스폿 용접성 및 재질안정성이 우수한 고강도 용융아연도금강판 및 그 제조방법
EP2400041B1 (fr) Matériau en acier apte au soudage et son procédé de production
EP2385149B1 (fr) Matériau en acier apte au soudage et son procédé de production
KR20190076758A (ko) 저온에서의 내파괴 특성이 우수한 극지 환경용 고강도 강재 및 그 제조방법
JP6973681B2 (ja) 電縫鋼管用熱延鋼板およびその製造方法、電縫鋼管およびその製造方法、ラインパイプ、建築構造物
EP2860276B1 (fr) Plaque d'acier
JPH11229077A (ja) 多層盛溶接部のｃｔｏｄ特性に優れた鋼板およびその製造方法
JP6277679B2 (ja) 耐ガス切断割れ性および大入熱溶接部靭性が優れた高張力鋼板
JP4645461B2 (ja) 耐延性亀裂発生特性と耐疲労亀裂伝播特性に優れた高強度鋼材およびその製造方法
JP5126780B2 (ja) 溶接熱影響部のｃｔｏｄ特性に優れた極低温用鋼
JP2007197776A (ja) 耐遅れ破壊特性と耐疲労き裂伝播特性に優れた高強度鋼材およびその製造方法
JP3336877B2 (ja) 脆性破壊伝播停止特性と溶接性に優れた厚肉高張力鋼板の製造方法
JP2005290553A (ja) 被削性と靭性および溶接性に優れた鋼板およびその製造方法
Nyo Influence of chromium and niobium content on the mechanical properties and heat affected zone simulations of low-carbon bainitic steels
JP2023112410A (ja) クラッド鋼溶接鋼管およびその製造方法

Legal Events

Date Code Title Description
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

17P Request for examination filed

Effective date: 20120726

AK Designated contracting states

Kind code of ref document: A2

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

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

Effective date: 20150205

RIC1 Information provided on ipc code assigned before grant

Ipc: B21B 3/02 20060101ALI20150130BHEP

Ipc: C21D 8/02 20060101ALI20150130BHEP

Ipc: C22C 38/04 20060101AFI20150130BHEP

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

INTG Intention to grant announced

Effective date: 20160622

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

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: CH

Ref legal event code: EP

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 849870

Country of ref document: AT

Kind code of ref document: T

Effective date: 20161215

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602010038536

Country of ref document: DE

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

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: 20161130

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

REG Reference to a national code

Ref country code: NL

Ref legal event code: MP

Effective date: 20161130

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

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: 20161130

Ref country code: SE

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: 20161130

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: 20170228

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: 20170301

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: 20170330

Ref country code: PL

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: 20161130

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: 20161130

Ref country code: BE

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

Effective date: 20161231

Ref country code: ES

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: 20161130

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: 20161130

Ref country code: FI

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: 20161130

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

Ref country code: NL

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: 20161130

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

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: 20161130

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: 20161130

Ref country code: CZ

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: 20161130

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: 20161130

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: 20161130

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: 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: 20170228

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: 20161130

Ref country code: IT

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: 20161130

Ref country code: BE

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: 20161130

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602010038536

Country of ref document: DE

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: 20161130

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

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

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20170228

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: 20161222

Ref country code: LI

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

Effective date: 20161231

Ref country code: CH

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

Effective date: 20161231

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20171002

26N No opposition filed

Effective date: 20170831

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

Ref country code: IE

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

Effective date: 20161222

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: 20161130

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

Ref country code: FR

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

Effective date: 20170130

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

Ref country code: GB

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

Effective date: 20170228

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: 20161130

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: 20101222

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: 20161130

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: 20161130

Ref country code: TR

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: 20161130

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 NON-PAYMENT OF DUE FEES

Effective date: 20161222

REG Reference to a national code

Ref country code: AT

Ref legal event code: UEP

Ref document number: 849870

Country of ref document: AT

Kind code of ref document: T

Effective date: 20161130

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: 20161130

REG Reference to a national code

Ref country code: DE

Ref legal event code: R081

Ref document number: 602010038536

Country of ref document: DE

Owner name: POSCO CO., LTD, POHANG-SI, KR

Free format text: FORMER OWNER: POSCO, POHANG, KR

Ref country code: DE

Ref legal event code: R081

Ref document number: 602010038536

Country of ref document: DE

Owner name: POSCO CO., LTD, POHANG- SI, KR

Free format text: FORMER OWNER: POSCO, POHANG, KR

Ref country code: DE

Ref legal event code: R081

Ref document number: 602010038536

Country of ref document: DE

Owner name: POSCO HOLDINGS INC., KR

Free format text: FORMER OWNER: POSCO, POHANG, KR

REG Reference to a national code

Ref country code: AT

Ref legal event code: PC

Ref document number: 849870

Country of ref document: AT

Kind code of ref document: T

Owner name: POSCO CO., LTD, KR

Effective date: 20230228

REG Reference to a national code

Ref country code: DE

Ref legal event code: R081

Ref document number: 602010038536

Country of ref document: DE

Owner name: POSCO CO., LTD, POHANG-SI, KR

Free format text: FORMER OWNER: POSCO HOLDINGS INC., SEOUL, KR

Ref country code: DE

Ref legal event code: R081

Ref document number: 602010038536

Country of ref document: DE

Owner name: POSCO CO., LTD, POHANG- SI, KR

Free format text: FORMER OWNER: POSCO HOLDINGS INC., SEOUL, KR

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

Ref country code: DE

Payment date: 20251105

Year of fee payment: 16

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

Ref country code: AT

Payment date: 20251105

Year of fee payment: 16