EP1143023B1 - Steel for welded structure purpose exhibiting no dependence of haz toughness on heat input and method for producing the same - Google Patents

Steel for welded structure purpose exhibiting no dependence of haz toughness on heat input and method for producing the same Download PDF

Info

Publication number
EP1143023B1
EP1143023B1 EP00966448A EP00966448A EP1143023B1 EP 1143023 B1 EP1143023 B1 EP 1143023B1 EP 00966448 A EP00966448 A EP 00966448A EP 00966448 A EP00966448 A EP 00966448A EP 1143023 B1 EP1143023 B1 EP 1143023B1
Authority
EP
European Patent Office
Prior art keywords
particles
steel
addition
oxides
heat input
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.)
Expired - Lifetime
Application number
EP00966448A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP1143023A4 (en
EP1143023A1 (en
Inventor
Ryuji Nippon Steel Corporation Technical UEMORI
Yukio Nippon Steel Corporation Technical TOMITA
Takuya Nippon Steel Corporation Technical HARA
Shuji Nippon Steel Corporation Technical AIHARA
Naoki Nippon Steel Corporation SAITOH
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.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
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 Nippon Steel Corp filed Critical Nippon Steel Corp
Publication of EP1143023A1 publication Critical patent/EP1143023A1/en
Publication of EP1143023A4 publication Critical patent/EP1143023A4/en
Application granted granted Critical
Publication of EP1143023B1 publication Critical patent/EP1143023B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium

Definitions

  • the present invention relates to a steel, for a welded structure, used for an offshore structure, a line pipe for transporting natural gas or crude oil, in architecture, in shipbuilding, for a bridge, for construction equipment or the like, and a method for producing the same.
  • the present invention relates to a steel, for a welded structure, requiring toughness at a weld zone, having a small prior austenite grain size at a weld heat-affected zone (hereunder referred to as "HAZ”) even when the steel is welded on a heat input condition that the heat input during welding widely ranges from 0.5 kJ/mm to over 150 kJ/mm, and being excellent in toughness at the weld heat-affected zone (hereunder referred to as "HAZ toughness”) without depending on the heat input condition.
  • HZ weld heat-affected zone
  • the difference between the influence of large heat input welding on a steel plate and that of ultra-large heat input welding on a steel plate is caused by the difference of their retention times at high temperatures of 1,400°C or more.
  • ⁇ grains prior austenite grains
  • inclusion particles finely dispersed in the steel
  • the inclusion particles being, for example, TiN described in JP-A-55-26164 or ZrN in "a steel for a large heat input welded structure characterized by containing, in weight %, 0.01 to 0.2% of C, 0.002 to 1.5% of Si, 0.5 to 2.5% of Mn, 0.002 to 0.1% of Ti and/or Zr, 0.004% or less of Ca and/or Mg, 0.001 to 0.1% of Ce and/or La, 0.005 to 0.1% of Al and 0.002 to 0.015% of N" as described in JP-A-52-17314.
  • nitrides contribute to fining crystal grains by showing a pinning effect of pinning prior ⁇ grains without dissolving in case of small or medium heat input welding
  • nitrides easily dissolve in a steel by welding heat and disappear in case of large or ultra-large heat input welding having an extremely long retention time at a high temperature of 1,400 °C or higher.
  • JP-A-59-190313 discloses a method for producing a steel material excellent in weldability, characterized by deoxidizing molten steel with Ti or Ti alloy and then adding Al, Mg, etc.
  • This production method is a technology to make use of the effect of increasing a ferrite ratio by making Ti oxides act as transformation nuclei of ferrite and to attempt to improve HAZ toughness by a method different from the former method of utilizing a pinning effect by precipitates such as nitrides.
  • the essence of those technologies is "to evenly and finely disperse Ti containing oxides usable for the formation of ferrite nuclei during ⁇ to a transformation, namely, the fining of a ferrite structure," and not to secure a pinning effect by nitrides and the like as described above, but to attempt to suppress the formation of a coarse brittle structure by accelerating ferrite transformation during ⁇ to ⁇ transformation arising in a cooling process and to attain the fining of a structure.
  • toughness improvement methods are all based on the technology to disperse and utilize relatively large oxides of about 1 ⁇ m as transformation nuclei in a coarse structure for promoting ferrite transformation in grains.
  • JP-A-9 310 147 discloses steel excellent in heat affected zone toughness having oxides of Ti and Mg of size 0.5-5 microns at a density of ⁇ 30 pieces/mm 2 and oxides of size 0.05-0.5 microns at a density of ⁇ 5000 pieces/mm 2
  • the object of the present invention is to provide a steel for a welded structure, excellent in HAZ toughness even if the steel is welded on any heat input condition, including ultra-large heat input, by improving the existing complex deoxidizing method, dispersing oxides and/or nitrides more finely and evenly than before, and further imposing, in addition, a ferrite transformation capability on the finely dispersed particles.
  • Mg is an element to enhance the cleanliness of a steel by acting as a strong deoxidizer and a desulfurizing agent and thus to improve HAZ toughness.
  • the object of the technology is to accelerate a finely dispersion of the increase of Ti oxides, which are intragranular transformation nuclei, by adding Mg for pinning the oxides.
  • the present inventors paying their attention to the function of Mg as a strong deoxidizer, had the idea that a fine dispersion of oxides might be expected if the sequence and amount of the addition of the deoxidizer in a Ti added steel were controlled in a steelmaking process by making use of the characteristic of Mg which more hardly causes aggregation and coarsening than Al.
  • the present inventors systematically investigated the state of oxides when Mg was added to molten steel deoxidized weakly by adding Ti.
  • oxides having two kinds of particle sizes were formed either when Ti and Mg were added in the order of Ti and then Mg or when Ti and Mg were added simultaneously and further, in the state of equilibrium, Mg was added again, after the molten steel was deoxidized by Si and Mn.
  • Mg containing oxides having grain sizes of 0.2 to 5.0 ⁇ m and the other kind is ultra-fine MgO or Mg containing oxides having a spinel structure having grain sizes of 0.005 to 0.1 ⁇ m. It is thought that these oxides are formed based on the following reasons.
  • oxides, at the ⁇ m level composed of Ti or those mainly composed of Ti are once formed by the addition of Ti or the simultaneous addition of Ti and a small amount of Mg.
  • Mg which has strong deoxidizing ability, is further added in this state, the oxides already formed are reduced by Mg and Mg containing oxides at the ⁇ m level, mainly composed of Mg, are formed finally.
  • the upper limit of the Mg addition amount is regarded to be 30 to 50 ppm when Mg is added, as described in JP-A-157787.
  • Mg can be added up to 100 ppm.
  • the oxides formed in steel become the nucleus forming sites of sulfides and nitrides during casting, cooling thereafter or reheating in hot rolling processes.
  • the states of the oxides existing in the steel can be arranged as described in items 1) and 2) below.
  • the state of oxides existing in steel it is preferable to observe 10 visual fields or more at a specified magnification (for example, about 100,000 times in case of ultra-fine oxides) and to measure the average particle interval.
  • the steel material with excellent HAZ toughness obtained by the oxides existing in the state of the above items 1) and/or 2) provides an epoch-making technology capable of extremely suppressing the toughness change at a HAZ, which largely depended on a heat input amount, formerly.
  • Figure 1 is a graph obtained by measuring the prior ⁇ particle sizes at HAZs on each condition (1 kJ/mm, 10 kJ/mm, 50 kJ/mm, 100 kJ/mm or 150 kJ/mm) using 0.10C-1.0Mn steel as the base steel, taking the heat input amounts along the axis of the abscissas.
  • the prior ⁇ particle size is obtained by taking the photographs (5 pictures or more), at a magnification of 50 to 200 times with an optical microscope, of microstructures obtained by extracting a part of a HAZ with cutting and processing, etc., applying polishing thereafter and further being subjected to Nitral corrosion, and by measuring the size by the cutting method.
  • the prior ⁇ particle sizes in the cases of 1 to 50 kJ/mm shown in Figure 1 are the ones obtained by this method.
  • the prior ⁇ particle size is obtained by calculating it as the prior ⁇ particle including grain boundary ferrite since the grain boundary ferrite forms along the prior ⁇ grain boundary, or by measuring the prior ⁇ particle size from the microstructure obtained by being heated on a prescribed condition and then rapid-cooled using a reproduction thermal cycling test machine adjusted so that the heat input equivalent amounts are identical.
  • the prior ⁇ particle sizes in the cases of 100 and 150 kJ/mm shown in Figure 1 are the ones obtained from the microstructure formed by using the reproduction thermal cycling test machine, which measuring method is the latter one.
  • the state of the oxides as specified in the above item 2) is a factor governing the fining of the prior ⁇ particle size.
  • MgO particles of a face centered cubic structure and MIIMIII 2 O 4 particles MII: Mg, Ca, Fe, Mn, etc., and MIII: Al, Ti, Cr, Mn, V, etc.
  • MII Mg, Ca, Fe, Mn, etc.
  • MIII Al, Ti, Cr, Mn, V, etc.
  • the suppression of the prior ⁇ particle growth at a HAZ, which has never been obtained in a conventional steel, can be attained.
  • one of the features of the present invention is, in addition to the remarkable improvement in intragranular transformation ability, to create the precipitation nuclei of nitrides by introducing oxides such as MgO, etc. finely in steel, thereby to realize the increase of the number of nitrides, and, in case of small heat input welding where nitrides effectively function, to obtain the prior ⁇ particles with the size of 10 to 200 ⁇ m at a HAZ due to the existence of those complex particles.
  • This is dissimilar to the conventional case where the pinning of crystal grains by making use of nitrides such as TiN, etc. is intended.
  • another feature of the present invention is that, even in large or ultra-large heat input welding where nitrides dissolve and the effect of improving toughness is never obtained formerly, the prior ⁇ particle size scarcely changes at a HAZ due to the effect of oxides alone on suppressing grain growth.
  • the method of adding Mg according to the present invention is, as described before, a method to add Si and Mn firstly, thereafter, either to adjust the oxygen amount in molten steel by adding Ti beforehand and thereafter to add a small amount of Mg little by little, or to add Ti and a small amount of Mg simultaneously and thereafter to finally add Mg again.
  • the final optimum amount of dissolved oxygen when Mg is added is about 0.1 to 50 ppm.
  • the lower limit of 0.1 ppm is the lowest amount of dissolved oxygen capable of forming fine Mg oxides.
  • the upper limit is set at 50 ppm.
  • C is a basic element for enhancing the strength of a base steel.
  • An addition amount of 0.01% or more is required for securing the enhancement effect. But, if it is excessively added in excess of 0.2%, weldability and toughness of a steel deteriorate, and therefore the upper limit is set at 0.2%.
  • Si is an indispensable element used as a deoxidizing element in steelmaking and an addition of 0.02% or more into a steel is required. However, if it is added in excess of 0.5%, HAZ toughness deteriorates, and therefore the upper limit is set at 0.5%.
  • Mn is an indispensable element for securing the strength and toughness of a base steel.
  • HAZ toughness deteriorates markedly, but in contrast, with the addition of less than 0.3%, the strength of a base steel is hardly secured. Therefore, the addition amount is limited in the range of 0.3 to 2%.
  • P is an element affecting the toughness of a steel. Since the toughness of not only a base steel but also a HAZ deteriorates greatly with a content exceeding 0.03%, the upper limit is set at 0.03%.
  • the range of the addition amount is set at 0.0001 to 0.03%.
  • Al is usually added as a deoxidizing agent.
  • the upper limit of Al is set at 0.05% since its addition in excess of 0.05% hinders the effect of Mg addition, and its lower limit is set at 0.0005% since Al addition of at least 0.0005% is required for forming MIIMIII 2 O 4 stably.
  • Ti is an element effective in the fining of crystal grains, acting as a deoxidizing agent and further an element to form nitrides.
  • a large amount of its addition causes the considerable deterioration of toughness due to the formation of carbides and therefore the upper limit has to be 0.05%.
  • the range of the addition amount is set at 0.003 to 0.05%.
  • Mg is a main alloying element in the present invention and is added as a deoxidizing agent mainly.
  • it is added in excess of 0.01%, coarse oxides tend to form and the toughness of a base steel and a HAZ deteriorates.
  • the range of the addition amount is set at 0.0001 to 0.010%.
  • O oxygen
  • oxygen is an essential element to form Mg containing oxides. If the oxygen amount finally remaining in a steel is less than 0.0001%, the number of oxides is insufficient, and therefore the lower limit is set at 0.0001%. On the other hand, if the amount of remaining oxygen exceeds 0.008%, coarse oxides increase and the toughness of a base steel and a HAZ deteriorates, and therefore the upper limit is set at 0.008%.
  • one or more elements of Cu, Ni, Cr, Mo, V, Nb, Zr, Ta and B may optionally be added as the elements which enhance strength and toughness.
  • Cu is an effective element in enhancing strength without deteriorating toughness.
  • the range of the content is set at 0.05 to 1.5%.
  • Ni is an effective element in enhancing toughness and strength, and, to secure the effect, an addition amount of 0.05% or more is required. However, when the addition amount exceeds 5%, weldability deteriorates, and therefore the upper limit is set at 5%.
  • Cr is added in the amount of 0.02% or more for effectively enhancing the strength of a steel by precipitation hardening, but a large amount of its addition exceeding 1.5% raises hardenability, generates a bainite structure and deteriorates toughness. Therefore, the upper limit is set at 1.5%.
  • Mo is an element which enhances hardenability and, at the same time, improves strength by forming carbonitrides.
  • the addition amount of 0.02% or more is required for securing the effect, but the addition in large amount exceeding 1.5% enhances strength excessively and deteriorates toughness considerably. Therefore, the range of the content is set at 0.02 to 1.5%.
  • V is an element which forms carbides and nitrides and is effective in enhancing strength, but the effect cannot be secured with the addition amount of less than 0.01% and, in contrast with this, toughness deteriorates with the addition amount of exceeding 0.1%. Therefore, the range of the content is set at 0.01 to 0.1%.
  • Nb is an element which forms carbides and nitrides and is effective in enhancing strength, but the effect cannot be secured with the addition amount of less than 0.0001% and toughness deteriorates with the addition amount of exceeding 0.2%. Therefore, the range of the content is set at 0.0001 to 0.2%.
  • Each of Zr and Ta is, like Nb, an element which forms carbides and nitrides and is effective in enhancing strength, but the effect cannot be secured with the addition amount of less than 0.0001% and, in contrast with this, toughness deteriorates with the addition amount of exceeding 0.05%. Therefore, the range of the content is set at 0.0001 to 0.05%.
  • B generally enhances hardenability when it is in the state of solid solution and is an element which decreases N in solid solution by forming BN and enhances the toughness of a weld heat-affected zone.
  • the above effects can be secured with the addition of 0.0003% or more, but its excessive addition causes the deterioration of toughness and therefore the upper limit is set at 0.005%.
  • Ca and REM suppress the generation of elongated MnS by forming sulfides and improve the properties in the plate thickness direction of a steel material, particularly a lamellar tear property.
  • Each of Ca and REM cannot secure those effects with the addition of less than 0.0005% and therefore the lower limit is set at 0.0005%.
  • the upper limit is set at 0.005%.
  • a steel containing above-mentioned components is refined in a steelmaking process, continuous casting, the heavy plate thus produced is heated and rolled.
  • a rolling method a heating and cooling method and a heat treatment method, even though methods conventionally applied in the relevant fields are adopted, there is no affection to HAZ toughness at all.
  • the fining of a prior ⁇ grain size at a HAZ according to the present invention demonstrates a large effect even in the case that not only HAZ toughness but also hardness matching, etc. have to be taken into consideration.
  • ⁇ vEo in Table 3 is obtained by calculating the difference of Charpy absorbed energy between the cases of small heat input (1.7 kJ/mm) and ultra-large heat input (150 kJ/mm), that is, [toughness in case of small heat input: vEo (J)] - [toughness in case of ultra-large heat input: vEo (J)], and each absorbed energy is an average of the values obtained by the measurement of three test pieces at 0°C.
  • ⁇ 1 and ⁇ 2 are average particle intervals of oxides calculated from ten photographs taken with an electron microscope in the magnification of 1,000 times for ⁇ 1 and 100,000 times for ⁇ 2.
  • Steel Chemical competition (mass%) C Si Mn P S Al Ti Mg O Cu Ni Cr 1 Invented steel 0.05 0.10 1.21 0.005 0.0030 0.0040 0.005 0.0033 0.0042 0.40 0.30 2 0.15 0.13 1.32 0.008 0.0053 0.0030 0.003 0.0041 0.0008 3 0.10 0.08 1.50 0.003 0.0044 0.0084 0.012 0.0003 0.0032 4 0.14 0.07 1.60 0.004 0.0035 0.0005 0.016 0.0019 0.0025 5 0.15 0.25 1.47 0.009 0.0053 0.0071 0.012 0.0019 0.0024 0.15 6 0.18 0.10 0.70 0.026 0.0029 0.0061 0.012 0.0025 0.0033 7 0.19 0.02 0.31 0.003 0.0228 0.00
  • the steels 1 to 22 show the examples according to the present invention.
  • the prior ⁇ grain sizes of these invented steels are all 200 ⁇ m or less in the wide heat input range from small heat input to ultra-large heat input.
  • the steels 20-2 and 21-2 have almost the same chemical compositions as those of the steels 20 and 21, respectively, the deoxidizing conditions are varied and the Mg amounts are somewhat different.
  • ⁇ 1 in case of the steel 20-2 and ⁇ 2 in case of the steel 21-2 are outside the range specified in the present invention, even in these cases, it is observed that the grain size of the steel 20-2 scarcely changes and it is understood that the grain size of the steel 21-2 is 200 ⁇ m or less at the heat input condition of 60.0 kJ/mm.
  • Charpy absorbed energy of all those invented steels exceeds 10 kgf-m and it shows that the above invented steels have high toughness.
  • the difference of Charpy absorbed energy between the cases of small heat input and ultra-large heat input is as small as 4 kgf-m at the largest and HAZ toughness does not vary even on the wide-ranging heat input conditions.
  • the steels 23 to 35 are the comparative steels produced on other conditions than that specified in the present invention. More specifically, the comparative steels 23, 24, 25, 26, 27, 29, 30, 33, 34 and 35 are the cases where at least one of the basic components or the selective elements is added in the amount outside the composition range specified in the present invention.
  • Comparative steels 28 and 31 are the cases where the amounts of Al and Ti are lower than their lower limits specified in the present invention, respectively. In these cases, prior ⁇ grain sizes coarsen as the heat input increases and thus both comparative steels have poor toughness.
  • Comparative steel 32 has no Mg addition, and under a small heat input condition, has good toughness. But under an ultra-large heat input condition, the steel has considerable deterioration of toughness and, consequently, the large Charpy absorbed energy difference of 10.3 kgf-m.
  • Comparative steels 33 and 34 have many fine oxides and, because of that, have largely deteriorated toughness even though the prior ⁇ grain sizes are sufficiently small compared with other cases.
  • Comparative steels 36 and 37 are the cases where their chemical compositions are the same as those of the invented steels 1 and 2, respectively, but the amounts of oxygen dissolved in molten steel exceed 50 ppm when the prescribed amounts of Mg are added at the final stage.
  • the growth of prior ⁇ grains at a HAZ can be suppressed, while disregarding heat input conditions, by either adding a prescribed amount of Mg properly after adding Ti or adding a prescribed amount of Mg properly after adding Ti and Mg simultaneously.
  • the present invention can, accordingly, greatly contribute to the development of various industrial technologies.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Steel (AREA)
EP00966448A 1999-10-12 2000-10-12 Steel for welded structure purpose exhibiting no dependence of haz toughness on heat input and method for producing the same Expired - Lifetime EP1143023B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP28941299 1999-10-12
JP28941299 1999-10-12
PCT/JP2000/007091 WO2001027342A1 (fr) 1999-10-12 2000-10-12 Acier pour structure soudee dont la tenacite de zone thermiquement affectee ne depend pas d'un apport de chaleur, et procede de production associe

Publications (3)

Publication Number Publication Date
EP1143023A1 EP1143023A1 (en) 2001-10-10
EP1143023A4 EP1143023A4 (en) 2003-01-02
EP1143023B1 true EP1143023B1 (en) 2005-06-01

Family

ID=17742916

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00966448A Expired - Lifetime EP1143023B1 (en) 1999-10-12 2000-10-12 Steel for welded structure purpose exhibiting no dependence of haz toughness on heat input and method for producing the same

Country Status (5)

Country Link
EP (1) EP1143023B1 (ko)
JP (1) JP3802810B2 (ko)
KR (1) KR100430067B1 (ko)
DE (1) DE60020522T2 (ko)
WO (1) WO2001027342A1 (ko)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4762450B2 (ja) * 2001-08-06 2011-08-31 新日本製鐵株式会社 母材靭性と溶接部ｈａｚ靭性に優れた高強度溶接構造用鋼の製造方法
KR100605717B1 (ko) * 2001-12-27 2006-08-01 주식회사 포스코 Ｔｉ-Ａｌ-Ｚｒ-Ｍｇ계 산화물 미세균일분산 용접 구조용 강
WO2004022807A1 (ja) * 2002-09-04 2004-03-18 Jfe Steel Corporation 大入熱溶接用鋼材およびその製造方法
DE60333400D1 (de) * 2003-05-27 2010-08-26 Nippon Steel Corp Herstellungsverfahren für hochfestes dünnes stahlblech mit hervorragender beständigkeit gegenüber verzögertem bruch nach dem umformen
AU2003292689A1 (en) * 2003-10-17 2005-05-05 Nippon Steel Corporation High strength thin steel sheet excellent in hole expansibility and ductility
DE102007004147A1 (de) 2007-01-22 2008-07-24 Heraeus Electro-Nite International N.V. Verfahren zum Beeinflussen der Eigenschaften von Gusseisen sowie Sauerstoffsensor
KR101142185B1 (ko) * 2007-12-07 2012-05-04 신닛뽄세이테쯔 카부시키카이샤 용접열 영향부의 ｃｔｏｄ 특성이 우수한 강 및 그 제조 방법
US8303734B2 (en) 2008-07-30 2012-11-06 Nippon Steel Corporation High strength thick steel material and high strength giant H-shape excellent in toughness and weldability and methods of production of same
RU2458174C1 (ru) 2009-05-19 2012-08-10 Ниппон Стил Корпорейшн Сталь для сварных конструкций и способ ее получения
TWI365915B (en) * 2009-05-21 2012-06-11 Nippon Steel Corp Steel for welded structure and producing method thereof
US9403242B2 (en) 2011-03-24 2016-08-02 Nippon Steel & Sumitomo Metal Corporation Steel for welding
US10280476B2 (en) 2014-04-15 2019-05-07 Nippon Steel & Sumitomo Metal Corporation H-section steel and method of producing the same

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03177535A (ja) * 1989-12-04 1991-08-01 Nippon Steel Corp 溶接用低温高靭性鋼の製造方法
JP2940647B2 (ja) * 1991-08-14 1999-08-25 新日本製鐵株式会社 溶接用低温高靱性鋼の製造方法
JP3476999B2 (ja) * 1996-05-21 2003-12-10 新日本製鐵株式会社 溶接熱影響部靭性の優れた鋼板
JP3752050B2 (ja) * 1997-02-19 2006-03-08 新日本製鐵株式会社 Ｍｇを含有する超大入熱溶接用鋼
JPH1121613A (ja) * 1997-05-07 1999-01-26 Nippon Steel Corp 低温靭性および耐サワー性に優れた鋼の製造方法
JP3752076B2 (ja) * 1998-04-15 2006-03-08 新日本製鐵株式会社 Ｍｇを含有する超大入熱溶接用鋼

Also Published As

Publication number Publication date
JP3802810B2 (ja) 2006-07-26
KR20010080751A (ko) 2001-08-22
EP1143023A4 (en) 2003-01-02
DE60020522T2 (de) 2005-11-24
WO2001027342A1 (fr) 2001-04-19
DE60020522D1 (de) 2005-07-07
KR100430067B1 (ko) 2004-05-03
EP1143023A1 (en) 2001-10-10

Similar Documents

Publication Publication Date Title
JP3863878B2 (ja) 溶接熱影響部の靭性が優れた溶接構造用鋼材、その製造方法及びこれを用いた溶接構造物
JP4213833B2 (ja) 溶接部靱性に優れた高靱性高張力鋼とその製造方法
EP1254275B1 (en) STEEL PLATE TO BE PRECIPITATING TiN + ZrN FOR WELDED STRUCTURES, METHOD FOR MANUFACTURING THE SAME AND WELDING FABRIC USING THE SAME
EP1339889B1 (en) STEEL PLATE TO BE PRECIPITATING TiN+CuS FOR WELDED STRUCTURES, METHOD FOR MANUFACTURING THE SAME, WELDING FABRIC USING THE SAME
EP1337678B1 (en) Steel plate to be precipitating tin+mns for welded structures, method for manufacturing the same and welding fabric using the same
EP1143023B1 (en) Steel for welded structure purpose exhibiting no dependence of haz toughness on heat input and method for producing the same
EP1052303A2 (en) High tensile strength steel product for high heat input welding, having excellent toughness in heat-affected zone
EP1262571B1 (en) Steel having weld heat-affected zone excellent in toughness
JPH11293382A (ja) Ｍｇを含有する超大入熱溶接用鋼
KR20020048034A (ko) 미세한ＴｉＯ산화물과 ＴｉＮ의 석출물을 갖는 고강도용접구조용 강의 제조방법
KR20020048199A (ko) 침질처리에 의한 ＴｉＮ석출물과 미세한 ＴｉＯ산화물을갖는 고강도 용접구조용 강의 제조방법
JP3520241B2 (ja) Ｍｇを含有する超大入熱溶接用鋼
JP2002371338A (ja) レーザー溶接部の靭性に優れた鋼
JP2003049236A (ja) 溶接熱影響部靱性および耐候性に優れた橋梁用高強度鋼およびその製造方法
JP3513001B2 (ja) 超大入熱溶接熱影響部の靱性に優れた溶接用高張力鋼
JP2003342670A (ja) 靭性の優れた非調質高張力鋼
KR20020045944A (ko) 이상역 제어압연에 의한 고강도 용접구조용 강재의 제조방법
KR100435488B1 (ko) 침질처리에 의해 ＴｉＮ과 ＺｒＮ의 석출물을 갖는용접구조용 강재의 제조방법
KR100435489B1 (ko) 침질처리에 의해 ＴｉＮ과 ＺｒＮ의 석출물을 갖는 고강도용접구조용 강재의 제조방법
JPH10298705A (ja) Ｍｇを含有する超大入熱溶接用鋼
KR20020045945A (ko) 침질처리와 이상역 제어압연에 의한 고강도 용접구조용강재의 제조방법
KR20020091845A (ko) 미세한 ＴｉＯ산화물과 ＴｉＮ의 석출물을 갖는용접구조용 강의 제조방법
KR20020048033A (ko) 침질처리에 의한 ＴｉＮ석출물과 미세한 ＴｉＯ산화물을갖는 용접구조용 강의 제조방법
KR20020047786A (ko) ＴｉＮ과 ＺｒＮ의 석출물을 갖는 용접구조용 강재와 그제조방법
KR20020041536A (ko) 침질처리에 의한 고강도 용접구조용 강재의 제조방법

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: 20010612

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

A4 Supplementary search report drawn up and despatched

Effective date: 20021113

AK Designated contracting states

Kind code of ref document: A4

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

17Q First examination report despatched

Effective date: 20030403

RBV Designated contracting states (corrected)

Designated state(s): DE FR

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

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): DE FR

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 60020522

Country of ref document: DE

Date of ref document: 20050707

Kind code of ref document: P

ET Fr: translation filed
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

26N No opposition filed

Effective date: 20060302

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 60020522

Country of ref document: DE

Representative=s name: VOSSIUS & PARTNER, DE

Effective date: 20130227

Ref country code: DE

Ref legal event code: R081

Ref document number: 60020522

Country of ref document: DE

Owner name: NIPPON STEEL & SUMITOMO METAL CORPORATION, JP

Free format text: FORMER OWNER: NIPPON STEEL CORP., TOKIO/TOKYO, JP

Effective date: 20130227

Ref country code: DE

Ref legal event code: R082

Ref document number: 60020522

Country of ref document: DE

Representative=s name: VOSSIUS & PARTNER PATENTANWAELTE RECHTSANWAELT, DE

Effective date: 20130227

REG Reference to a national code

Ref country code: FR

Ref legal event code: CA

Effective date: 20130913

Ref country code: FR

Ref legal event code: CD

Owner name: NIPPON STEEL & SUMITOMO METAL CORPORATION, JP

Effective date: 20130913

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 17

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 18

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 19

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

Ref country code: FR

Payment date: 20180913

Year of fee payment: 19

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

Ref country code: DE

Payment date: 20181002

Year of fee payment: 19

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 60020522

Country of ref document: DE

Representative=s name: VOSSIUS & PARTNER PATENTANWAELTE RECHTSANWAELT, DE

Ref country code: DE

Ref legal event code: R081

Ref document number: 60020522

Country of ref document: DE

Owner name: NIPPON STEEL CORPORATION, JP

Free format text: FORMER OWNER: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOKYO, JP

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60020522

Country of ref document: DE

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

Ref country code: DE

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

Effective date: 20200501

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: 20191031