EP1143023A1 - Acier pour structure soudee dont la tenacite de zone thermiquement affectee ne depend pas d'un apport de chaleur, et procede de production associe - Google Patents

Acier pour structure soudee dont la tenacite de zone thermiquement affectee ne depend pas d'un apport de chaleur, et procede de production associe Download PDF

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EP1143023A1
EP1143023A1 EP00966448A EP00966448A EP1143023A1 EP 1143023 A1 EP1143023 A1 EP 1143023A1 EP 00966448 A EP00966448 A EP 00966448A EP 00966448 A EP00966448 A EP 00966448A EP 1143023 A1 EP1143023 A1 EP 1143023A1
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Prior art keywords
steel
heat input
oxides
less
toughness
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EP1143023B1 (fr
EP1143023A4 (fr
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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
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Nippon Steel Corp
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Nippon Steel Corp
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    • 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.
  • 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.
  • Japanese Unexamined Patent Publication No. S59-190313 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.
  • 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.
  • 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.
  • the gist of the present invention is as follows:
  • a steel for a welded structure with HAZ toughness not susceptible to heat input characterized by: containing, in terms of wt%,
  • a steel for a welded structure with HAZ toughness not susceptible to heat input according to the item (1) characterized by further containing, in terms of wt%, one or more of
  • a steel for a welded structure with HAZ toughness not susceptible to heat input according to any one of the items (1) to (3), characterized by having the prior austenite grain sizes of 10 to 200 ⁇ m in its HAZ structure without depending on weld heat input.
  • a method for producing a steel for a welded structure with HAZ toughness not susceptible to heat input according to any one of the items (1) to (4), characterized by: casting the steel in the state of adjusting the dissolved oxygen amount at 50 ppm or less by adding 0.003 to 0.05 wt% of Ti and a required amount of Mg successively or simultaneously after carrying out a weak deoxidation treatment by adding Si and Mn in a steelmaking process; or casting the steel after further adding Mg so that the final content of Mg is 0.01 wt% or less.
  • a method for producing a steel for a welded structure with HAZ toughness not susceptible to heat input according to any one of the items (1) to (4), characterized by: casting the steel in the state of adjusting the dissolved oxygen amount at 50 ppm or less by adding 0.003 to 0.05 wt% of Ti and required amounts of Al, Ca and Mg successively or simultaneously after carrying out a weak deoxidation treatment by adding Si and Mn at a steelmaking process; or casting the steel after further adding Mg so that the final content of Mg is 0.01 wt% or less.
  • 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 is more hardly caused 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 is 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 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 Japanese Unexamined Patent Publication No. H9-157787.
  • 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 present invention relates to a steel material with excellent HAZ toughness obtained by the oxides existing in the state of the above items 1) and/or 2), and provides an epoch-making technology capable of extremely suppressing the toughness change at a HAZ, which largely depended on a heat input amount, formerly.
  • Mg contained oxides according to the present invention have an extremely large intragranular transformation ability.
  • 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.
  • MIIMIII 2 O 4 particles MII: Mg, Ca, Fe, Mn, etc.
  • MIII Al, Ti, Cr, Mn, V, etc.
  • the complex particles of Mg contained oxides and sulfides and/or nitrides (TiN, etc.) as schematically shown in Figure 2.
  • 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, which is dissimilar to the conventional case where the pinning of crystal grains by making use of nitrides such as TiN, etc. is intended, 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.
  • 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%.
  • oxygen is an essential element to form Mg contained 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 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.
  • Production method Plate thickness (mm) d1 ( ⁇ m) d2 ( ⁇ m) d3 ( ⁇ m) ⁇ 1 ( ⁇ m) ⁇ 2 ( ⁇ m) vEo (kgf ⁇ m) ⁇ vEo (kgf ⁇ m) 1
  • Controlled rolling and controlled cooling 40 35 60 100 60 8.3 15.0 2.0 2 Regular rolling and air cooling 40 40 60 100 55 8.2 16.0 2.5 3 Regular rolling and air cooling 250 65 80 140 75 9.3 18.0 3.1 4
  • Controlled rolling and controlled cooling 60 45 50 120 65 9.0 22.0 3.0 5
  • Controlled rolling and controlled cooling 50 60 70 90 50 7.5 20.5 -2.3 7
  • 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 the 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.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
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  • Treatment Of Steel In Its Molten State (AREA)
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EP00966448A 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 Expired - Lifetime EP1143023B1 (fr)

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

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EP1143023A1 true EP1143023A1 (fr) 2001-10-10
EP1143023A4 EP1143023A4 (fr) 2003-01-02
EP1143023B1 EP1143023B1 (fr) 2005-06-01

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EP (1) EP1143023B1 (fr)
JP (1) JP3802810B2 (fr)
KR (1) KR100430067B1 (fr)
DE (1) DE60020522T2 (fr)
WO (1) WO2001027342A1 (fr)

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EP1533392A1 (fr) * 2002-09-04 2005-05-25 JFE Steel Corporation Acier pour soudures a fort apport thermique et son procede de production
EP1637618A1 (fr) * 2003-05-27 2006-03-22 Nippon Steel Corporation Tole mince en acier a resistance elevee presentant une resistance excellente a la rupture differee apres formation et procede de preparation associe, et parties automobiles necessitant une certaine resistance fabriquees a partie de tole mince en acier a resistance elevee
WO2008089894A1 (fr) * 2007-01-22 2008-07-31 Heraeus Electro-Nite International N.V. Procédé permettant d'influer sur les propriétés de la fonte
EP2192205A1 (fr) * 2003-10-17 2010-06-02 Nippon Steel Corporation Plaques métalliques haute résistance ayant d'excellents pouvoir d'expansion de trou et ductilité
EP2218800A1 (fr) * 2007-12-07 2010-08-18 Nippon Steel Corporation Acier avec zone affectée par la chaleur de soudage possédant d'excellentes propriétés ctod et procédé de fabrication de l'acier
EP2305850A1 (fr) * 2008-07-30 2011-04-06 Nippon Steel Corporation Produits d'acier épais de haute résistance présentant d excellentes caractéristiques en termes d endurance et d aptitude au soudage, acier en forme de h ultra épais de haute résistance et procédés de fabrication de ceux-ci
EP2385149A1 (fr) * 2009-05-19 2011-11-09 Nippon Steel Corporation Matériau en acier apte au soudage et son procédé de production
EP2400041A1 (fr) * 2009-05-21 2011-12-28 Nippon Steel Corporation Matériau en acier apte au soudage et son procédé de production
US9403242B2 (en) 2011-03-24 2016-08-02 Nippon Steel & Sumitomo Metal Corporation Steel for welding
EP3133181A4 (fr) * 2014-04-15 2017-10-11 Nippon Steel & Sumitomo Metal Corporation Poutre d'acier en h et son procédé de fabrication

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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

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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
JPH09310147A (ja) * 1996-05-21 1997-12-02 Nippon Steel Corp 溶接熱影響部靭性の優れた鋼板
JPH10298705A (ja) * 1997-02-19 1998-11-10 Nippon Steel Corp 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

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PATENT ABSTRACTS OF JAPAN vol. 015, no. 425 (C-0879), 29 October 1991 (1991-10-29) & JP 03 177535 A (NIPPON STEEL CORP), 1 August 1991 (1991-08-01) *
PATENT ABSTRACTS OF JAPAN vol. 1998, no. 04, 31 March 1998 (1998-03-31) & JP 09 310147 A (NIPPON STEEL CORP), 2 December 1997 (1997-12-02) *
PATENT ABSTRACTS OF JAPAN vol. 1999, no. 02, 26 February 1999 (1999-02-26) & JP 10 298705 A (NIPPON STEEL CORP), 10 November 1998 (1998-11-10) *
PATENT ABSTRACTS OF JAPAN vol. 1999, no. 04, 30 April 1999 (1999-04-30) & JP 11 021613 A (NIPPON STEEL CORP), 26 January 1999 (1999-01-26) *
See also references of WO0127342A1 *

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EP1533392A4 (fr) * 2002-09-04 2005-12-07 Jfe Steel Corp Acier pour soudures a fort apport thermique et son procede de production
EP1533392A1 (fr) * 2002-09-04 2005-05-25 JFE Steel Corporation Acier pour soudures a fort apport thermique et son procede de production
EP1637618A1 (fr) * 2003-05-27 2006-03-22 Nippon Steel Corporation Tole mince en acier a resistance elevee presentant une resistance excellente a la rupture differee apres formation et procede de preparation associe, et parties automobiles necessitant une certaine resistance fabriquees a partie de tole mince en acier a resistance elevee
EP1637618A4 (fr) * 2003-05-27 2006-10-18 Nippon Steel Corp Tole mince en acier a resistance elevee presentant une resistance excellente a la rupture differee apres formation et procede de preparation associe, et parties automobiles necessitant une certaine resistance fabriquees a partie de tole mince en acier a resistance elevee
US8182740B2 (en) 2003-10-17 2012-05-22 Nippon Steel Corporation High-strength steel sheets excellent in hole-expandability and ductility
EP2192205A1 (fr) * 2003-10-17 2010-06-02 Nippon Steel Corporation Plaques métalliques haute résistance ayant d'excellents pouvoir d'expansion de trou et ductilité
US8192683B2 (en) 2003-10-17 2012-06-05 Nippon Steel Corporation High-strength steel sheets excellent in hole-expandability and ductility
US8449741B2 (en) 2007-01-22 2013-05-28 Heraeus Electro-Nite International N.V. Method for influencing the properties of cast iron, and oxygen sensor
US8557176B2 (en) 2007-01-22 2013-10-15 Heraeus Electro-Nite International N.V. Method for influencing the properties of cast iron
WO2008089894A1 (fr) * 2007-01-22 2008-07-31 Heraeus Electro-Nite International N.V. Procédé permettant d'influer sur les propriétés de la fonte
EP2218800A1 (fr) * 2007-12-07 2010-08-18 Nippon Steel Corporation Acier avec zone affectée par la chaleur de soudage possédant d'excellentes propriétés ctod et procédé de fabrication de l'acier
US8361248B2 (en) 2007-12-07 2013-01-29 Nippon Steel Corporation Steel superior in CTOD properties of weld heat-affected zone and method of production of same
EP2218800A4 (fr) * 2007-12-07 2011-07-27 Nippon Steel Corp Acier avec zone affectée par la chaleur de soudage possédant d'excellentes propriétés ctod et procédé de fabrication de l'acier
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
EP2305850A1 (fr) * 2008-07-30 2011-04-06 Nippon Steel Corporation Produits d'acier épais de haute résistance présentant d excellentes caractéristiques en termes d endurance et d aptitude au soudage, acier en forme de h ultra épais de haute résistance et procédés de fabrication de ceux-ci
EP2305850A4 (fr) * 2008-07-30 2011-12-28 Nippon Steel Corp Produits d'acier épais de haute résistance présentant d excellentes caractéristiques en termes d endurance et d aptitude au soudage, acier en forme de h ultra épais de haute résistance et procédés de fabrication de ceux-ci
EP2385149A4 (fr) * 2009-05-19 2012-07-18 Nippon Steel Corp Matériau en acier apte au soudage et son procédé de production
EP2385149A1 (fr) * 2009-05-19 2011-11-09 Nippon Steel Corporation Matériau en acier apte au soudage et son procédé de production
US8668784B2 (en) 2009-05-19 2014-03-11 Nippon Steel & Sumitomo Metal Corporation Steel for welded structure and producing method thereof
EP2400041A4 (fr) * 2009-05-21 2012-10-17 Nippon Steel Corp Matériau en acier apte au soudage et son procédé de production
EP2400041A1 (fr) * 2009-05-21 2011-12-28 Nippon Steel Corporation Matériau en acier apte au soudage et son procédé de production
US8920713B2 (en) 2009-05-21 2014-12-30 Nippon Steel & Sumitomo Metal Corporation Steel for welded structure and producing method thereof
US9403242B2 (en) 2011-03-24 2016-08-02 Nippon Steel & Sumitomo Metal Corporation Steel for welding
EP3133181A4 (fr) * 2014-04-15 2017-10-11 Nippon Steel & Sumitomo Metal Corporation Poutre d'acier en h et son procédé de fabrication
US10280476B2 (en) 2014-04-15 2019-05-07 Nippon Steel & Sumitomo Metal Corporation H-section steel and method of producing the same

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DE60020522T2 (de) 2005-11-24
DE60020522D1 (de) 2005-07-07
JP3802810B2 (ja) 2006-07-26
KR100430067B1 (ko) 2004-05-03
KR20010080751A (ko) 2001-08-22
WO2001027342A1 (fr) 2001-04-19
EP1143023B1 (fr) 2005-06-01
EP1143023A4 (fr) 2003-01-02

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