WO2012108543A1 - 長大脆性き裂伝播停止特性に優れる板厚５０ｍｍ以上の厚鋼板およびその製造方法ならびに長大脆性き裂伝播停止性能を評価する方法および試験装置 - Google Patents

長大脆性き裂伝播停止特性に優れる板厚５０ｍｍ以上の厚鋼板およびその製造方法ならびに長大脆性き裂伝播停止性能を評価する方法および試験装置 Download PDF

Info

Publication number
WO2012108543A1
WO2012108543A1 PCT/JP2012/053201 JP2012053201W WO2012108543A1 WO 2012108543 A1 WO2012108543 A1 WO 2012108543A1 JP 2012053201 W JP2012053201 W JP 2012053201W WO 2012108543 A1 WO2012108543 A1 WO 2012108543A1
Authority
WO
WIPO (PCT)
Prior art keywords
thickness
plate
steel plate
region
less
Prior art date
Application number
PCT/JP2012/053201
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
恒久 半田
聡 伊木
西村　公宏
弘資 潮海
貞末　照輝
遠藤　茂
Original Assignee
Ｊｆｅスチール株式会社
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 Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to KR1020137020860A priority Critical patent/KR101584235B1/ko
Priority to CN2012800078166A priority patent/CN103348030A/zh
Publication of WO2012108543A1 publication Critical patent/WO2012108543A1/ja

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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—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 by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—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 by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
    • C21D8/0463—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment following 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
    • C22C38/02—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
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/006—Crack, flaws, fracture or rupture
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/006—Crack, flaws, fracture or rupture
    • G01N2203/0062—Crack or flaws
    • G01N2203/0066—Propagation of crack

Definitions

  • the present invention relates to a steel plate having a thickness of 50 mm or more excellent in brittle crack propagation arrestability suitable for use in a large container ship (Mega-container carrier), a bulk carrier (bulk carrier), and the like, and a method for producing the same. About.
  • the present invention also relates to a method and a test apparatus for evaluating the long brittle crack propagation stopping performance equivalent to an actual ship.
  • Container ships and bulk carriers have a structure with a large upper aperture in order to improve the carrying capacity and the cargo handling efficiency. For this reason, in order to ensure the rigidity and longitudinal strength of the hull, it is necessary to increase the thickness of the outer plate of the vessel (outer plate of vessel's body).
  • TEU Japanese-foot Equivalent Unit
  • the plate thickness of the hull outer plate becomes 50 mm or more, and the fracture toughness (fracture toughness) is due to the plate thickness effect. ) Is reduced, and welding heat input is also increased, so that the fracture toughness of the welded part tends to be further reduced.
  • TEU wenty-foot Equivalent Unit
  • a technique for making the structure of the surface part of the steel material ultrafine without increasing the alloy cost has been proposed as a means for improving the brittle crack propagation stopping property.
  • a shear-lip plastic deformation area generated in the steel surface layer portion is effective in improving the brittle crack propagation stopping property. Focusing on a certain point, a method is disclosed in which the propagation energy of propagating brittle cracks is absorbed by refining the crystal grains of the shear lip portion.
  • the process of cooling the surface layer portion below the Ar 3 transformation point by controlled cooling and then stopping the controlled cooling to reheat the surface layer portion above the transformation point is repeated once or more. During this time, by rolling the steel material, it is repeatedly transformed or recrystallized due to deformation, and a superfine ferrite structure or a bainite structure is generated in the surface layer portion. Is.
  • Patent Document 2 discloses a ferrite material having a microstructure mainly composed of ferrite-pearlite, and ferrite particles having both surface portions with a circle-equivalent mean particle diameter of 5 ⁇ m or less and an aspect ratio of 2 or more. Consists of a layer having a ferrite structure of 50% or more and further suppresses local recrystallization phenomenon (phenomenon) by reducing the maximum rolling reduction per pass during finish rolling to 12% or less. However, it is disclosed that an excellent improvement in brittle crack propagation stopping characteristics can be obtained by suppressing the variation in ferrite grain size.
  • Patent Document 3 discloses that a steel material having excellent brittle crack propagation characteristics after being subjected to plastic deformation is contained in crystal grains produced by the methods described in the following (a) to (d). A steel material mainly composed of fine ferrite formed with a sub-grain is disclosed.
  • the brittle crack propagation stop property after plastic deformation is improved without requiring complicated temperature control such as cooling and recuperation of the steel sheet surface layer.
  • Patent Document 4 describes that a separation is generated in a direction parallel to the plate thickness direction on the fracture surface of the steel material by developing a texture.
  • the (110) plane X-ray intensity ratio is 2 by controlled rolling. It is described that coarse particles having an equivalent circle diameter of 20 ⁇ m or more are 10% or less.
  • Patent Document 5 as a welded structural steel having excellent brittle crack propagation stopping performance at a welded joint (welded joint), the X-ray plane strength ratio of the (100) plane at the rolled surface inside the plate thickness is 1.5.
  • a steel sheet characterized by having the above is disclosed, and by the texture development, the crack propagation direction is changed with respect to the direction perpendicular to the stress loading direction, and the steel plate is brittle. It is described that a crack is induced from a welded joint part to the base metal side to improve brittle crack propagation stopping performance as a joint.
  • the X-ray intensity ratio of the (211) plane at the rolled surface at the center of the plate thickness is 1.3 or more, and the (100) plane X-ray at the rolled surface at the 1/4 thickness portion.
  • a steel sheet characterized by having a strength ratio of 1.5 or more and a (100) plane X-ray intensity ratio at the rolled surface in the plate surface layer portion of 1.5 or more is disclosed.
  • a crack is generated near the tip of a brittle crack that penetrates from the surface of the steel plate, and the crack acts as a crack propagation resistance, improving the brittle crack propagation stopping performance against the brittle crack propagating in the plate thickness direction.
  • brittle crack propagation behavior of welded steel plates for shipbuilding with a thickness of less than 50 mm has been experimentally studied by The Shipbuilding Research Association Japan 147th Committee.
  • Non-Patent Document 1 a steel plate base material such as aggregate (also referred to as a stiffener) (Non-Patent Document 1), and a hull structure to which a steel plate having a thickness of 50 mm or more is applied. It is a big problem in ensuring safety.
  • Patent Documents 1 to 6 described above do not describe the lengthened brittle crack propagation stopping characteristics, and cannot solve the problems clarified in Non-Patent Document 1.
  • Patent Documents 1 to 6 there is no description in the techniques described in Patent Documents 1 to 6 regarding the method and test apparatus for evaluating the long brittle crack propagation stopping characteristics equivalent to actual ships, and to solve the problem of safety evaluation equivalent to actual ships. I can't.
  • the present invention provides a thick steel plate that stops a brittle crack that has grown before reaching a large-scale fracture (catastrophic fracture) even when a brittle fracture occurs in a steel plate having a thickness of 50 mm or more and a welded portion thereof. It aims at providing the manufacturing method.
  • an object of the present invention is to provide a method and a test apparatus for evaluating the long brittle crack propagation stopping performance equivalent to an actual ship.
  • the long and brittle crack is a brittle crack having a length of 1 m or more that enters from another adjacent steel plate.
  • the present inventors have investigated the relationship between texture morphology and brittle crack propagation stopping characteristics (sometimes referred to as arrestability) for many steel plates with different chemical compositions and rolling conditions, and have long brittleness.
  • the effect of the distribution of the arrest performance (which is affected by toughness and texture) on the crack propagation arrest phenomenon in the thickness direction was investigated.
  • dynamic FEM analysis in which the distance between the tab plate tips (distance between tips of tab plates) or the distance between load points (distance between loading points) can be used to simulate a long brittle crack propagation characteristic equivalent to an actual ship.
  • the evaluation method and test apparatus for the long-scale ESSO test were studied.
  • the long brittle crack propagation stoppage performance has been dramatically improved and has been stopped so far. It has been found that a thick brittle crack or a long brittle crack propagating through its weld can be stopped with a steel plate under conditions equivalent to an actual ship without stress reflection. Furthermore, as a result of dynamic FEM analysis, the evaluation method and test apparatus for a long-sized ESSO test corresponding to an actual ship without stress reflection were found by setting the distance between the tab plate tips and the distance between the load points to predetermined values. .
  • the present invention is intended for a steel plate with a thickness of 50 mm or more.
  • a steel plate having a thickness (t) of 50 mm or more, and a width of 20% of the thickness (t) at the center of the thickness in the tip shape of the long brittle crack propagation stop portion in the cross section in the thickness direction With respect to the maximum crack length in the region where the stop crack length in the region is 1/4 to 1/10 of the plate thickness (t) or 3/4 to 9/10 of the plate thickness (t) from the steel plate surface, A plate thickness (t) excellent in a long brittle crack propagation stop characteristic, characterized in that it is formed in a concave recess portion that is shorter than the length of the long brittle crack by at least the length of the plate thickness (t).
  • Steel composition includes mass%, C: 0.15% or less, Si: 0.60% or less, Mn: 0.80 to 1.80%, S: 0.001 to 0.05% , Ti: 0.005 to 0.050% or Nb: 0.001 to 0.1%, and at least one selected from the group consisting of: Cu: 2.0% or less, V: 0.2% or less Ni: 2.0% or less, Cr: 0.6% or less, Mo: 0.6% or less, W: 0.5% or less, B: 0.0050% or less, Zr: 0.5% or less (1) to (3) characterized in that it comprises at least one selected from the group consisting of the remaining Fe and unavoidable impurities (1) to (3).
  • a steel material having the composition described in (4) is heated to a temperature of 900 to 1350 ° C., and then rolled at a cumulative rolling reduction of 10% or more in a temperature range of a steel plate surface temperature of 1000 to 850 ° C.
  • the steel sheet surface temperature at the end of rolling at a surface temperature of 900 to 600 ° C. and the steel sheet internal temperature being 50 to 150 ° C. higher than the steel sheet surface temperature, and thereafter with a one-pass rolling reduction of 7% or more and a cumulative rolling reduction of 50% or more.
  • the sheet is cooled to 400 ° C. at a cooling rate of 5 ° C./s or more, and the plate thickness (t ) Is a manufacturing method of a thick steel plate of 50 mm or more.
  • Evaluation method (9) In a test device that evaluates and confirms the propagation stop performance for a large brittle crack with a crack propagation length of 1 m or more using a large test piece with a width of 2 m or more, the distance between the tab plate tips of the test device to which the test piece is attached is Test apparatus for evaluating long brittle crack propagation stopping performance (10), characterized by being 2.8 times or more the width of the test piece (9) In the test apparatus according to (9), further, the test apparatus for evaluating the long brittle crack propagation stopping performance, wherein the distance between the load points of the test apparatus is 4.1 times or more of the test piece width.
  • a brittle crack propagation stopping performance in a thick steel plate having a thickness (t) of 50 mm or more, and it is long in a thick material having a thickness of 50 mm or more, which has been difficult until now.
  • a brittle crack can be stopped under conditions equivalent to an actual ship without stress reflection, which is extremely useful in industry.
  • the dynamic FEM analysis model dynamic finite element analysis model
  • parametric model parametric model
  • the dynamic FEM analysis model in case the distance between load points for investigating the influence of the stress reflection on the evaluation of the long brittle crack propagation stop characteristic is shown.
  • the dynamic FEM analysis model in case the distance between load points for investigating the influence of stress reflection on the evaluation of long brittle crack propagation stop characteristics is shown.
  • the figure which shows the influence of the test conditions (distance from a test piece edge part) which acts on a dynamic stress intensity factor (dynamic stress intensity factor) as an analysis result by the dynamic analysis model of FIG.
  • the tip shape of the long brittle crack propagation stop portion in the cross section in the thickness direction is defined. The reason for limitation of the present invention will be described below.
  • FIG. 1 schematically shows a tip shape (long brittle crack stop position 3) of a propagation stop portion of a long brittle crack 2 in a cross section in the thickness direction of a steel plate 1 having a thickness (t) of 50 mm or more according to the present invention. .
  • the shape of the tip of the long brittle crack propagation stop portion is determined from the position of the long brittle crack stop in the region having a width of 20% of the plate thickness (t) at the plate thickness central portion, and the plate thickness (t) from the steel plate surface.
  • the shortest interval hereinafter referred to as depth a
  • At least the length of the plate thickness (t) is set to a shape having a recessed portion having a substantially U-shape that is short by a depth a in the advancing direction of the long brittle crack.
  • the arrest performance in the upper and lower width regions of 10% or more) is improved.
  • the area of improving the arrest performance, t a is preferably 50% or less due to restrictions of the rolling load (rolling load).
  • Arrest performance area width around the mid-thickness with improved and t a is the thickness of less than 20%, of the 1 / 4-1 / 10 parts near the plate thickness (t) (sheet thickness (t) 1 / 4 position and 1/10 position, the region between 1/4 position and 1/10 position) and the vicinity of 3/4 to 9/10 part of plate thickness (t) (3/4 of plate thickness (t)) And the 9/10 position, the area between the 3/4 position and the 9/10 position) is not sufficiently reduced, and the vicinity of 1/4 to 1/10 part of the plate thickness (t) and the plate In the vicinity of 3/4 to 9/10 part of the thickness (t), the crack does not stop and propagates, so at least 20%.
  • the area where the arrest performance is superior to other areas has a short stop length for the large brittle crack, and a concave recess is formed in the direction of travel, so the tip shape of the long brittle crack propagation stop section Is a substantially U-shaped recessed portion in which a region of at least 20% of the plate thickness (t) at the central portion of the plate thickness is recessed with respect to the traveling direction of the long brittle crack.
  • the shape of the substantially U-shaped recess is to reduce the fracture driving force in the vicinity of 1/4 to 1/10 of the plate thickness (t) and in the vicinity of 3/4 to 9/10 of the plate thickness (t).
  • the brittle crack stop length in the region of 20% of the plate thickness at the center of the plate thickness is 1/4 to 1/10 of the plate thickness (t) and 3/4 to 9/10 of the plate thickness (t). Since it is necessary to shorten at least the length of the plate thickness (t) from the brittle crack stop length in the region, the depth a of the recessed portion is at least the plate thickness (t) with respect to the traveling direction of the large brittle crack.
  • a concave shape equal to the length of.
  • Depth a is a large brittle crack stop position (maximum crack length) in the region where 1/4 to 1/10 of the plate thickness (t) and 3/4 to 9/10 of the plate thickness (t) in FIG. Also passes through the intersection of a line perpendicular to the plate thickness direction and a line parallel to the plate thickness direction showing a region width of 20% of the plate thickness at the center of the plate thickness and the long brittle crack propagation stop position. It is defined as the length of the shortest interval among the intervals with the line perpendicular to the thickness direction.
  • the longest crack propagation zone in the range of 1/4 to 1/10 of the plate thickness (t) or 3/4 to 9/10 of the plate thickness (t) ( 1 is observed)
  • the shape of the long brittle crack propagation stop position drawn in the thickness direction is defined in the present invention in the comparison between the vicinity of the thickness center portion and these regions.
  • the tip shape of the long brittle crack propagation stop portion described above can be confirmed on the fracture surface of the long ESSO test piece 4 shown in FIG.
  • the long ESSO test piece 4 has a test plate 6 and a run-up plate (Crac-running plate) 5 joined by a CO 2 weld 8, and the run-up plate 5 has an electrogas weld (electrogas weld) perpendicular to the CO 2 weld 8. arc weld) 7, and a brittle crack (not shown) generated from a mechanical notch 9 propagates along the electrogas weld 7 and is perpendicular to the loading direction of the test plate 6.
  • the test plate 6 is rushed.
  • the load direction is indicated by the arrow R. D. Rolling direction.
  • the long and brittle crack propagation stop characteristic means that a long ESOP test piece 4 having a long brittle crack propagation distance before entering the test plate 6 is used, and stress reflection is similar to that in an actual ship. This refers to those evaluated by a testing machine that has a sufficiently long distance between the tab plate tips and the load load point without any influence.
  • the stress reflection here refers to reflection of a compressive stress wave generated by the occurrence and propagation of a brittle crack at a tab plate of testing machine. When this stress reflection occurs, the compressive stress wave returns to the brittle crack propagation portion, so that the brittle crack tends to stop.
  • the steel sheet according to the present invention preferably has a texture described below.
  • the X-ray intensity ratio of the (211) plane or the (100) plane at the rolling surface in the region of at least 20% of the plate thickness at the center of the plate thickness is 1.5 or more, the plate thickness of 1/4 t to 1/10 t, or the plate
  • the X-ray intensity ratio of the (110) plane at the rolling surface of thickness 3 / 4t to 9 / 10t is 1.3 or more.
  • the X-ray intensity ratio of the (110) plane on the rolled surface with a thickness of 1/4 t to 1/10 t is less than 1.3, the brittleness in the region of 20% or more of the thickness of the central portion of the thickness is obtained.
  • the crack stop length is not shorter than the brittle crack stop length in the region of the plate thickness from 1/4 t to 1/10 t, and is not shorter than the plate thickness by the thickness of about 1/4 t to 1/10 t (point A in FIG. 1).
  • the failure driving force of the longest crack propagation part near the point A ′ does not decrease. Therefore, the X-ray intensity ratio of the (110) plane at the rolled surface having a thickness of 1/4 t to 1/10 t was limited to 1.3 or more. The same applies to the thickness 3 / 4t to 9 / 10t part.
  • vTrs-12X (100) -22X (211) ⁇ (T-75) /0.64 (However, in the formula, X (211) is the (211) plane X-ray intensity ratio at the rolling surface in the region at least 20% of the plate thickness (t) at the center of the plate thickness, and X (100) is the same site (100) Plane X-ray intensity ratio, vTrs (° C.) is the fracture surface transition temperature obtained by the 2 mm V notch Charpy impact test at the same site, and T is the service temperature (° C.) of the steel sheet)
  • This parameter formula defines the toughness of the steel sheet by vTrs according to the texture in order to ensure the brittle crack propagation stop toughness of the target area in the texture.
  • vTrs is defined so as to satisfy the above equation.
  • the X-ray intensity ratio of the (211) plane or the (100) plane needs to be 1.5 or more. Since the texture greatly contributes to the improvement of brittle crack propagation stop toughness, the coefficient of X (211) is made larger than X (100) in the equation.
  • the preferable component composition and manufacturing conditions of the steel sheet having the above-described characteristics are as follows. In the description,% is mass%. [Ingredient composition] C: 0.15% or less C is necessary to ensure strength. From the viewpoint of securing strength, the lower limit is preferably 0.02%. However, if the C content exceeds 0.15%, the weld heat affected zone (HAZ) toughness decreases, so the content was limited to 0.15% or less. In order to further develop the texture of the (211) plane and the (100) plane, the preferable range is 0.03% or less. Si: 0.60% or less Si is an element effective for increasing the strength. In order to acquire the effect, it is preferable to contain 0.01% or more. If the Si content exceeds 0.60%, the weld heat affected zone (HAZ) toughness is remarkably deteriorated, so it is limited to 0.60% or less.
  • Mn 0.80 to 1.80% Mn is an element effective for increasing the strength, and the lower limit is set to 0.80% from the viewpoint of securing the strength. However, if the amount of Mn exceeds 1.80%, there is a concern about deterioration of the base material toughness. Therefore, Mn is set in the range of 0.80 to 1.80%. A preferred range is 1.00 to 1.70%.
  • Ti forms carbide (nitride) precipitates (precipitate)
  • HAZ welded heat-affected zone
  • Nb is also effective for precipitation strengthening and toughness improvement. Moreover, the recrystallization of austenite is suppressed, and the effect by the rolling conditions described later is promoted. In order to obtain these effects, addition of 0.001% or more is necessary, but if added over 0.1%, the quenched structure tends to become needle-like and the toughness tends to deteriorate. The upper limit is 1%.
  • Cu 2.0% or less, V: 0.2% or less, Ni: 2.0% or less, Cr: 0.6% or less, Mo: 0.6% or less, W: 0.5% or less, B: At least one selected from 0.0050% or less and Zr: 0.5% or less Cu: 2.0% or less Cu can be used mainly for precipitation strengthening. In order to acquire the effect, it is preferable to contain 0.05% or more. If the Cu content exceeds 2.0%, precipitation strengthening becomes excessive and the toughness deteriorates. Therefore, the Cu content is preferably in the range of 2.0% or less.
  • V 0.2% or less
  • V is a component that can be used for solid solution strengthening and precipitation strengthening. In order to acquire the effect, it is preferable to contain 0.001% or more. If the V content exceeds 0.2%, the base metal toughness and weldability are greatly impaired. Therefore, the V content is preferably in the range of 0.2% or less.
  • Ni 2.0% or less Ni is effective in improving strength and toughness and preventing Cu cracking during rolling when Cu is added. In order to acquire the effect, it is preferable to contain 0.05% or more. However, since it is expensive and its effect is saturated even if it is added excessively, it is preferably added in a range of 2.0% or less.
  • Cr 0.6% or less Cr has an effect of increasing strength. In order to acquire the effect, it is preferable to contain 0.01% or more. However, if the content exceeds 0.6%, the weld zone toughness deteriorates, so the Cr content is preferably in the range of 0.6% or less.
  • Mo 0.6% or less Mo has an effect of increasing the strength at normal temperature and high temperature. In order to acquire the effect, it is preferable to contain 0.01% or more. However, if the content exceeds 0.6%, the weldability deteriorates, so the content is preferably in the range of 0.6% or less.
  • W 0.5% or less W has an effect of increasing the high-temperature strength. In order to acquire the effect, it is preferable to contain 0.05% or more. However, if it exceeds 0.5%, not only is the toughness deteriorated, but it is expensive, so it is preferably contained in a range of 0.5% or less.
  • B 0.0050% or less B precipitates as BN during rolling, and fines ferrite grains after rolling. In order to acquire the effect, it is preferable to contain 0.0010% or more. However, if it exceeds 0.0050%, the toughness deteriorates, so it is limited to 0.0050% or less.
  • Zr 0.5% or less
  • Zr is an element that increases the strength and improves the plating cracking resistance of the galvanized material. In order to acquire the effect, it is preferable to contain 0.03% or more. However, since the weld toughness deteriorates if the content exceeds 0.5%, the Zr content is preferably 0.5% as an upper limit.
  • the steel according to the present invention is the balance Fe and unavoidable impurities in addition to the above component composition. Inevitable impurities include P: 0.035% or less, Al: 0.08% or less, N: 0.012% or less, 0: 0.05% or less, Mg: 0.01% or less, and the like. Acceptable.
  • the temperature and cooling rate are average values in the thickness direction.
  • Heating temperature The steel material is heated to a temperature of 900 to 1350 ° C.
  • a heating temperature of 900 ° C. or higher is necessary for homogenization of the material and controlled rolling described later, and a temperature of 1350 ° C. or lower is marked by surface oxidation when the temperature is excessively high. This is because coarsening of crystal grains is unavoidable.
  • the upper limit is preferably set to 1150 ° C.
  • the steel plate at the end of rolling has a one-pass rolling reduction of 7% or more and a cumulative rolling reduction of 50% or more.
  • Hot rolling under the condition of a surface temperature of 850 to 550 ° C When the steel plate surface temperature is 900 to 600 ° C and the steel plate internal temperature is 50 to 150 ° C higher than the steel plate surface temperature, the surface vicinity is almost two phases.
  • the steel plate and the inside of the steel sheet are substantially non-recrystallization regions.
  • the basis of the (211) plane texture which is a kind of transformation texture effective for crack generation at the brittle crack tip, is formed.
  • the one-pass rolling reduction rate it is more preferable to set the one-pass rolling reduction rate to 10% or more.
  • a more preferable cooling start temperature is 700 ° C. or higher.
  • the steel plate according to the present invention when the steel plate according to the present invention is less than 50 mm thick, it has excellent brittle crack propagation characteristics.
  • FIG. 3A, 3B, and 3C show dynamic FEM analysis models, and FIG. 4 shows the results.
  • FIG. 3A is a parametric model for determining the condition without stress reflection, and is a model for analyzing the influence of the distance (2A in FIG. 3A) between the tester tab plates 11 (thickness 200 mm) that affects the stress reflection. is there.
  • FIG. 3B is a model when the distance of the load load point 10 of the test machine to be used is set to 10 m
  • FIG. 3C is a model when the distance of the load load point 10 of the test machine to be used is set to 5 m.
  • FIG. 4 shows the FEM analysis results.
  • FIG. 4 shows the change in the dynamic stress intensity factor (fracture driving force during brittle crack propagation) Kd of the crack during propagation from the occurrence of fracture to the entry into the test plate.
  • FIG. 4 shows the analysis result obtained by the model when the distance between the load points of the test machine used is set to 5 m and 10 m. The large tension of the 10 m model between the load points shown in FIG. 3B is shown. If a long ESSO test is performed with the test jig shape, it is recognized that the evaluation is performed under conditions equivalent to an actual ship without stress reflection.
  • the evaluation method of the long-brittle crack propagation stopping performance under conditions equivalent to an actual ship without stress reflection is the test piece length or the distance between the tab plate tips of the test apparatus to which the test piece is attached is 2 .Times.8 times or more ( ⁇ 6800 mm / 2400 mm), and further, the distance between the load points of the test apparatus was 4.1 times or more ( ⁇ 10000 mm / 2400 mm) of the test piece width.
  • the distance between the tab plate tips of the test device to which the test piece is attached is 2.8 times or more of the test piece width. ( ⁇ 6800 mm / 2400 mm), and further, the distance between the load points of the test apparatus was 4.1 times or more the width of the test piece ( ⁇ 10000 mm / 2400 mm).
  • Thick steel plates were manufactured according to the conditions shown in Table 2 using steel slabs adjusted to various chemical compositions shown in Table 1. For each thick steel plate thus obtained, the X-ray intensity ratio between the (211) plane and the (100) plane of the central portion (high arrest performance region) of the plate thickness (t) is measured, and the Charpy fracture surface transition temperature ( Ductile-Brittle transition temperature of Charimpact test) vTrs was investigated. Further, the X-ray intensity ratio of the (110) plane of 1/8 part of the plate thickness (t) (representative part in the region of 1/4 to 1/10 of the plate thickness (t)) was measured.
  • a large ESSO test piece having the dimensions shown in FIG. 2 was prepared using the above-mentioned thick steel plate (the original thickness of the plate thickness (t)), and the test was performed. It was used for. The test was performed under the conditions of a stress of 257 N / mm 2 and a temperature of ⁇ 10 ° C.
  • the stress 257 N / mm 2 is the maximum allowable stress of the yield strength 40 kgf / mm 2 grade steel plate frequently used in the hull, and the temperature ⁇ 10 ° C. is the design temperature of the ship.
  • the long ESSO test was conducted using a large tensile test jig shown in FIG.
  • Table 3B shows the results of the long ESSO test.
  • examples Nos. 2, 3, 6, 8, 9, 12, 14
  • the brittle cracks stopped at the fillet welds
  • comparative examples No. 1, 4, 5, 7, 10, 11, In 13, 15, 16
  • the brittle crack did not stop.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Heat Treatment Of Steel (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
PCT/JP2012/053201 2011-02-08 2012-02-07 長大脆性き裂伝播停止特性に優れる板厚５０ｍｍ以上の厚鋼板およびその製造方法ならびに長大脆性き裂伝播停止性能を評価する方法および試験装置 WO2012108543A1 (ja)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020137020860A KR101584235B1 (ko) 2011-02-08 2012-02-07 장대 취성 균열 전파 정지 특성이 우수한 판 두께 50㎜ 이상의 후강판 및 그의 제조 방법 그리고 장대 취성 균열 전파 정지 성능을 평가하는 방법 및 시험 장치
CN2012800078166A CN103348030A (zh) 2011-02-08 2012-02-07 长脆性裂纹传播停止特性优异的板厚为50mm以上的厚钢板及其制造方法、以及评价长脆性裂纹传播停止性能的方法及试验装置

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011-024495 2011-02-08
JP2011024495 2011-02-08

Publications (1)

Publication Number Publication Date
WO2012108543A1 true WO2012108543A1 (ja) 2012-08-16

Family

ID=46638754

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/053201 WO2012108543A1 (ja) 2011-02-08 2012-02-07 長大脆性き裂伝播停止特性に優れる板厚５０ｍｍ以上の厚鋼板およびその製造方法ならびに長大脆性き裂伝播停止性能を評価する方法および試験装置

Country Status (5)

Country Link
JP (3) JP5598485B2 (enrdf_load_stackoverflow)
KR (1) KR101584235B1 (enrdf_load_stackoverflow)
CN (2) CN103348030A (enrdf_load_stackoverflow)
TW (1) TWI523953B (enrdf_load_stackoverflow)
WO (1) WO2012108543A1 (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103286128A (zh) * 2013-05-30 2013-09-11 山西太钢不锈钢股份有限公司 一种超级双相不锈钢s32750中板轧制工艺
WO2014024445A1 (ja) * 2012-08-06 2014-02-13 Ｊｆｅスチール株式会社 厚鋼板の長大脆性き裂伝播停止性能の評価方法、それに用いる試験装置および厚鋼板の製造方法
WO2014208072A1 (ja) * 2013-06-26 2014-12-31 Ｊｆｅスチール株式会社 厚鋼板の脆性破壊伝播停止性能の評価方法

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103348030A (zh) * 2011-02-08 2013-10-09 杰富意钢铁株式会社 长脆性裂纹传播停止特性优异的板厚为50mm以上的厚钢板及其制造方法、以及评价长脆性裂纹传播停止性能的方法及试验装置
WO2016105062A1 (ko) * 2014-12-24 2016-06-30 주식회사 포스코 취성균열전파 저항성이 우수한 고강도 강재 및 그 제조방법
KR101657827B1 (ko) * 2014-12-24 2016-09-20 주식회사 포스코 취성균열전파 저항성이 우수한 구조용 극후물 강재 및 그 제조방법
JP6112265B2 (ja) * 2015-03-12 2017-04-12 Ｊｆｅスチール株式会社 高強度極厚鋼板およびその製造方法
CN110878404B (zh) * 2015-09-18 2022-03-04 杰富意钢铁株式会社 结构用高强度厚钢板
JP6338022B2 (ja) * 2016-02-24 2018-06-06 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
JP6665658B2 (ja) * 2016-04-21 2020-03-13 日本製鉄株式会社 高強度厚鋼板
CN111433585B (zh) * 2017-11-22 2022-10-28 杰富意钢铁株式会社 厚钢板的脆性裂纹传播停止性能的评价方法
KR101999015B1 (ko) 2017-12-24 2019-07-10 주식회사 포스코 취성균열 전파 저항성이 우수한 구조용 강재 및 그 제조방법
KR101999022B1 (ko) 2017-12-26 2019-07-10 주식회사 포스코 피로균열 전파 억제 특성이 우수한 구조용 고강도 강재 및 그 제조방법
KR102200222B1 (ko) 2018-12-19 2021-01-08 주식회사 포스코 냉간 벤딩성이 우수한 고강도 구조용 강재 및 그 제조방법
KR102648172B1 (ko) 2019-03-28 2024-03-14 제이에프이 스틸 가부시키가이샤 라인 파이프용 강재 및 그의 제조 방법 그리고 라인 파이프 및 그의 제조 방법
CN110863149A (zh) * 2019-11-13 2020-03-06 浙江金洲管道科技股份有限公司 一种热镀锌钢管及其制造方法
JP7288196B2 (ja) * 2019-12-16 2023-06-07 日本製鉄株式会社 溶接構造体
JP7288197B2 (ja) * 2019-12-16 2023-06-07 日本製鉄株式会社 溶接構造体
KR20230159710A (ko) * 2021-06-10 2023-11-21 제이에프이 스틸 가부시키가이샤 후강판의 취성 균열 전파 정지 성능의 평가 방법

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007327137A (ja) * 2006-05-12 2007-12-20 Jfe Steel Kk 隅肉および十字溶接部の脆性亀裂伝播停止特性に優れる厚物鋼板およびその製造方法
JP2008013831A (ja) * 2006-07-07 2008-01-24 Jfe Steel Kk 高ヤング率溶接構造用厚鋼板およびその製造方法
JP2008045174A (ja) * 2006-08-18 2008-02-28 Jfe Steel Kk 脆性亀裂伝播停止特性に優れた構造用高強度厚鋼板およびその製造方法
JP2008156750A (ja) * 2006-11-30 2008-07-10 Jfe Steel Kk 板厚方向の脆性亀裂伝播停止特性に優れる板厚５０ｍｍ以上の鋼板およびその製造方法
JP2008179878A (ja) * 2006-12-28 2008-08-07 Jfe Steel Kk 脆性亀裂伝播停止特性に優れた高張力厚鋼板およびその製造方法
JP2008214652A (ja) * 2007-02-28 2008-09-18 Jfe Steel Kk 脆性亀裂伝播停止特性に優れた構造用高強度厚鋼板およびその製造方法
JP2010242211A (ja) * 2009-03-17 2010-10-28 Jfe Steel Corp 板厚方向の耐疲労亀裂伝播特性に優れた厚鋼板およびその製造方法
JP2011127207A (ja) * 2009-12-21 2011-06-30 Sumitomo Metal Ind Ltd アレスト特性に優れた高強度厚肉鋼板およびその製造方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07100814B2 (ja) 1990-09-28 1995-11-01 新日本製鐵株式会社 脆性亀裂伝播停止特性と低温靭性の優れた鋼板の製造方法
JP2659661B2 (ja) 1993-01-06 1997-09-30 新日本製鐵株式会社 継手部の脆性破壊伝播停止性能の優れた溶接用構造用鋼とその製造方法
JP3548349B2 (ja) 1996-09-18 2004-07-28 新日本製鐵株式会社 塑性変形後の耐脆性破壊特性の優れた構造用鋼板
JP3467767B2 (ja) 1998-03-13 2003-11-17 Ｊｆｅスチール株式会社 脆性亀裂伝播停止特性に優れた鋼材およびその製造方法
JP4077167B2 (ja) 2001-02-28 2008-04-16 株式会社神戸製鋼所 アレスト特性に優れた鋼板およびその製法
JP4899034B2 (ja) * 2008-02-14 2012-03-21 Ｄｏｗａエレクトロニクス株式会社 化合物半導体作成用のガリウム原料
JP5337412B2 (ja) * 2008-06-19 2013-11-06 株式会社神戸製鋼所 脆性亀裂伝播停止特性に優れた厚鋼板およびその製造方法
CN103348030A (zh) * 2011-02-08 2013-10-09 杰富意钢铁株式会社 长脆性裂纹传播停止特性优异的板厚为50mm以上的厚钢板及其制造方法、以及评价长脆性裂纹传播停止性能的方法及试验装置

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007327137A (ja) * 2006-05-12 2007-12-20 Jfe Steel Kk 隅肉および十字溶接部の脆性亀裂伝播停止特性に優れる厚物鋼板およびその製造方法
JP2008013831A (ja) * 2006-07-07 2008-01-24 Jfe Steel Kk 高ヤング率溶接構造用厚鋼板およびその製造方法
JP2008045174A (ja) * 2006-08-18 2008-02-28 Jfe Steel Kk 脆性亀裂伝播停止特性に優れた構造用高強度厚鋼板およびその製造方法
JP2008156750A (ja) * 2006-11-30 2008-07-10 Jfe Steel Kk 板厚方向の脆性亀裂伝播停止特性に優れる板厚５０ｍｍ以上の鋼板およびその製造方法
JP2008179878A (ja) * 2006-12-28 2008-08-07 Jfe Steel Kk 脆性亀裂伝播停止特性に優れた高張力厚鋼板およびその製造方法
JP2008214652A (ja) * 2007-02-28 2008-09-18 Jfe Steel Kk 脆性亀裂伝播停止特性に優れた構造用高強度厚鋼板およびその製造方法
JP2010242211A (ja) * 2009-03-17 2010-10-28 Jfe Steel Corp 板厚方向の耐疲労亀裂伝播特性に優れた厚鋼板およびその製造方法
JP2011127207A (ja) * 2009-12-21 2011-06-30 Sumitomo Metal Ind Ltd アレスト特性に優れた高強度厚肉鋼板およびその製造方法

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014024445A1 (ja) * 2012-08-06 2014-02-13 Ｊｆｅスチール株式会社 厚鋼板の長大脆性き裂伝播停止性能の評価方法、それに用いる試験装置および厚鋼板の製造方法
CN103286128A (zh) * 2013-05-30 2013-09-11 山西太钢不锈钢股份有限公司 一种超级双相不锈钢s32750中板轧制工艺
WO2014208072A1 (ja) * 2013-06-26 2014-12-31 Ｊｆｅスチール株式会社 厚鋼板の脆性破壊伝播停止性能の評価方法
CN105308431A (zh) * 2013-06-26 2016-02-03 杰富意钢铁株式会社 厚钢板的脆性断裂传播停止性能的评价方法
CN105308431B (zh) * 2013-06-26 2017-11-28 杰富意钢铁株式会社 厚钢板的脆性断裂传播停止性能的评价方法

Also Published As

Publication number Publication date
JP5598485B2 (ja) 2014-10-01
JP2012180590A (ja) 2012-09-20
CN108130479A (zh) 2018-06-08
CN103348030A (zh) 2013-10-09
TWI523953B (zh) 2016-03-01
JP2014052385A (ja) 2014-03-20
KR101584235B1 (ko) 2016-01-11
TW201250007A (en) 2012-12-16
KR20130114239A (ko) 2013-10-16
JP2014145131A (ja) 2014-08-14

Similar Documents

Publication Publication Date Title
WO2012108543A1 (ja) 長大脆性き裂伝播停止特性に優れる板厚５０ｍｍ以上の厚鋼板およびその製造方法ならびに長大脆性き裂伝播停止性能を評価する方法および試験装置
JP5445720B1 (ja) アレスト性に優れた高強度厚鋼板
RU2518830C1 (ru) Горячекатаный стальной лист и способ его изготовления
JP5337412B2 (ja) 脆性亀裂伝播停止特性に優れた厚鋼板およびその製造方法
JP5598617B1 (ja) 脆性亀裂伝播停止特性に優れた大入熱溶接用高強度厚鋼板およびその製造方法
WO2017047088A1 (ja) 構造用高強度厚鋼板およびその製造方法
JP5217391B2 (ja) 板厚方向の脆性亀裂伝播停止特性に優れる板厚５０ｍｍ以上の鋼板およびその製造方法
JP5759109B2 (ja) 脆性亀裂伝播停止特性に優れた鋼材、およびその製造方法
JP2009068050A (ja) 母材低温靭性に優れた大入熱溶接用高張力鋼板
JP6165116B2 (ja) 長大脆性き裂伝播停止性能に優れる厚鋼板の製造方法
WO2016143345A1 (ja) 高強度極厚鋼板およびその製造方法
JP5668668B2 (ja) 溶接熱影響部の靭性に優れた鋼材並びに溶接継手、溶接継手の製造方法
JP6477743B2 (ja) 脆性き裂伝播停止特性および溶接熱影響部靭性に優れた高強度極厚鋼板およびその製造方法
WO2013175745A1 (ja) 脆性き裂伝播停止特性に優れた構造用高強度厚鋼板およびその製造方法
JP5135872B2 (ja) 隅肉および十字溶接部の脆性亀裂伝播停止特性に優れる厚物鋼板およびその製造方法
JP5838801B2 (ja) 厚鋼板及び厚鋼板の製造方法
JP7508029B1 (ja) 高強度極厚鋼板およびその製造方法
JP7468814B1 (ja) 高強度極厚鋼板およびその製造方法
WO2024105967A1 (ja) 高強度極厚鋼板およびその製造方法
JP2008156751A (ja) 板厚方向の脆性亀裂伝播停止特性に優れる板厚５０ｍｍ以上の鋼板およびその製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12744971

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20137020860

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12744971

Country of ref document: EP

Kind code of ref document: A1