EP1520912A2 - Stahl mit durch Schweissen beeinflusster Zone mit ausgezeichneter Zähigkeit - Google Patents

Stahl mit durch Schweissen beeinflusster Zone mit ausgezeichneter Zähigkeit Download PDF

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Publication number
EP1520912A2
EP1520912A2 EP04026201A EP04026201A EP1520912A2 EP 1520912 A2 EP1520912 A2 EP 1520912A2 EP 04026201 A EP04026201 A EP 04026201A EP 04026201 A EP04026201 A EP 04026201A EP 1520912 A2 EP1520912 A2 EP 1520912A2
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Prior art keywords
steel
toughness
oxide particles
haz
affected zone
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Application number
EP04026201A
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English (en)
French (fr)
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EP1520912A3 (de
EP1520912B1 (de
Inventor
Masanori Nippon Steel Corp. Minagawa
Toshihiko Nippon Steel Corp. Koseki
Yuji Nippon Steel Corp. Funatsu
Jun Nippon Steel Corp. Ohtani
Tomohiko Nippon Steel Corp. Hada
Tadashi Nippon Steel Corp. Ishikawa
Masaaki Nippon Steel Corp. Nagahara
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Nippon Steel Corp
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Nippon Steel Corp
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Priority claimed from JP2000033242A external-priority patent/JP2001226739A/ja
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Publication of EP1520912A3 publication Critical patent/EP1520912A3/de
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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
    • 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
    • C22C38/02—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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium

Definitions

  • This invention relates to a steel for a welded structure excellent in the toughness of a weld heat-affected zone (hereinafter referred to as "HAZ”) used for ships, marine construction, medium and high-rise buildings and so on.
  • HZ weld heat-affected zone
  • Japanese Unexamined Patent Publication No. H3-264614 proposes a method of improving the toughness of a HAZ by using the multiphase precipitates of Ti nitrides and MnS as the nuclei of ferrite transformation.
  • Japanese Unexamined Patent Publication No. H4-143246 proposes a method of improving the toughness of a HAZ by using the multiphase precipitates of Ti nitrides and BN as the nuclei of the precipitation of intergranular ferrite.
  • steels containing Ti oxides are used in various fields of steel plates, sections and the like.
  • a steel containing Ti oxides is very effective for improving the toughness of a high heat input HAZ, and the application of the technology to a high tensile steel is promising.
  • the principle is as follows: Ti nitrides, MnS and the like precipitate using Ti oxides, which are stable even at the melting temperature of a steel, as precipitation sites during the temperature drop after welding; then fine ferrite forms using the precipitated Ti nitrides, MnS and the like as the sites of the formation; and, as a result, the formation of coarse ferrite detrimental to toughness is suppressed and, thus, the toughness is prevented from deteriorating.
  • the cause is the coarsening and agglomeration of Ti oxides and, when it is attempted to increase the number of Ti oxides, coarse Ti oxides 5 ⁇ m or more in diameter, namely so-called inclusions, increase. Inclusions 5 ⁇ m or more in diameter are harmful since they serve as starting points of the fracture of a structure, leading to the deterioration of toughness. To further improve the toughness of a HAZ, therefore, it is necessary to use oxides not prone to coarsen or agglomerate but which are apt to disperse in a steel in finer grains than Ti oxides.
  • the method of adding Ti to molten steel substantially not containing strongly deoxidizing elements such as Al is often employed. It is difficult, however, to control the number and dispersion of Ti oxides in a steel by simply adding Ti to molten steel and, moreover, it is also difficult to control the number and dispersion of the precipitates of TiN, MnS and the like. As a consequence, in a steel wherein the Ti oxides are dispersed solely by means of the deoxidation by Ti, there are problems of causing, for instance, an insufficient number of Ti oxides, toughness variation in the thickness direction of a steel plate and the like.
  • the upper limit of Al amount is set at a very low figure of 0.007%.
  • the toughness of a base metal may deteriorate caused by an insufficient amount of AlN precipitates or the like.
  • the toughness of a weld metal may deteriorate.
  • Japanese Unexamined Patent Publication No. H6-293937 proposes a technique of utilizing Ti-Al composite oxides formed by adding Al immediately after adding Ti. It is possible, by this technique, to significantly improve the toughness of a HAZ under high heat input welding. Lately, however, shipbuilding and construction industries are promoting a further increase in weld heat input to 200 kJ/cm or more or even to 1,000 kJ/cm and, as a consequence, a steel having higher HAZ toughness is sought. In this situation, the improvement of toughness in the vicinity of a weld fusion zone is particularly required.
  • the object of the present invention is, in order to significantly improve the properties of a HAZ even under the above ultra-high heat input welding, to provide a steel excellent in the toughness of a weld heat-affected zone, wherein a HAZ excellent in toughness can be realized by further suppressing the coarsening of austenite grains when the steel is heated for a long time at a high temperature.
  • the present invention has been established for solving the above problems, and the gist of the present invention is as follows:
  • the present invention is explained in detail hereafter.
  • the present inventors studied the method of making reheated austenite grains fine in a HAZ, which is heated to 1,400°C or higher, using an oxide.
  • volume percentage of the dispersed grains The higher the volume percentage of the dispersed grains and the larger the diameter of each of them, the larger the effect of the dispersed grains to pin the crystal grain boundaries. It has to be noted, however, that there is an upper limit to the volume percentage of the dispersed grains, determined by the concentrations of the component elements of the grains contained in the steel in question. Therefore, supposing that the volume percentage is constant, a good pinning effect is obtained when the diameter of the grains is not very large. From this viewpoint, the present inventors carried out studies on how to increase the volume percentage of oxides and how to obtain an adequate grain size.
  • the present inventors discovered that it was possible to increase the volume percentage of oxides, or the amount of oxides, when Ca at 3% or more and Al at 1% or more were contained in the composition of the oxide particles formed in a steel. Based on this result, the present invention stipulated that the oxide particles in a steel contained at least Ca, Al and O in their composition, and that the oxide particles contained, in the mass percentage of the elements excluding O, Ca at 3% or more and Al at 1% or more.
  • the present invention stipulated that the oxide particles in a steel contained at least Ca, Al, Mg and O in their composition, and that, in the mass percentage of the elements excluding O, the oxide particles contained Ca at 5% or more, Al at 5% or more and Mg at 1% or more.
  • the present inventors discovered that a further increase in the volume percentage of the dispersed grains could be brought about through the combined effect of oxides and sulfides when sulfides such as CaS and MgS precipitated around oxide particles.
  • the present invention stipulated that the particles in a steel contained at least Ca, Al, O and S in their composition, and that, in the mass percentage of the elements excluding O, the particles contained Ca at 5% or more, Al at 5% or more and S at 1% or more, otherwise, that the particles in a steel contained at least Ca, Al, Mg, O and S in their composition, and that, in the mass percentage of the elements excluding O, the particles contained Ca at 5% or more, Al at 5% or more, Mg at 1% or more and S at 1% or more.
  • the present inventors confirmed that the effects of the present invention remained unaffected in the above case, even when the oxide particles contained Mg and/or REM, having a deoxidizing strength rated between Al and Ca, as a component element or component elements in the balance of the elements whose contents were specified above.
  • the present inventors also confirmed that the effects of the present invention were not hindered even when the particles contained deoxidizing elements milder than Al, such as Si, Mn and Ti, unavoidably included in the oxide particles and/or impurity elements, such as S, inevitably combining with Ca and so on.
  • the effect of pinning crystal grain boundaries by dispersed grains increases as the volume percentage of the dispersed grains increases and the size of each of the grains becomes larger.
  • the present inventors reasoned that, when the volume percentage of the dispersed grains was constant, the number of the oxide particles would increase as the size of each of the particles became smaller and, as a consequence, pinning effect would increase, and that, when the grain size was too small, the proportion of the crystal grain boundaries occupied by the dispersed grains would decrease and, as a result, the pinning effect would also decrease.
  • the present inventors discovered that the pinning effect was the largest when the grain size was from 0.005 to 2.0 ⁇ m. It was also made clear that the pinning force for arresting the migration of austenite grain boundaries became stronger as the size of the dispersed grains increased. Thus, the present inventors discovered that, among the dispersed grains having grain sizes from 0.005 to 2.0 ⁇ m, those having grain sizes from 0.1 to 2.0 ⁇ m were particularly effective. Pinning effect decreases gradually when the grain size decreases to below 0.1 ⁇ m and, when it is below 0.005 ⁇ m, little of the pinning effect appears.
  • the oxide particles larger than 2.0 ⁇ m have pinning effect, they sometimes serve as the starting points of brittle fracture and, for this reason, they are undesirable from the viewpoint of the material properties of a steel.
  • the present invention stipulates that the required diameter of the oxide particles is from 0.005 to 2.0 ⁇ m, preferably from 0.1 to 2.0 ⁇ m.
  • the present inventors studied the number of pinning grains required for securing a desired toughness of a HAZ.
  • a HAZ toughness required of a steel material is different in a complicated manner depending on the application of the steel material and the method of welding employed in the application.
  • the present inventors discovered that, in order to satisfy a HAZ toughness, for example, of 50 J or more in terms of the absorbed energy at a test temperature of -40°C, corresponding to the toughness level required when a high strength steel for ship construction was welded under a high heat input, which was considered to be a case where especially stringent property requirements were applied, it was necessary that the density of oxide particles 0.005 to 2.0 ⁇ m in circle-equivalent diameter was 100 pieces/mm 2 or more, as shown in Fig. 1.
  • an appropriate upper limit of the density of the oxide particles is 3,000 pieces/mm 2 .
  • the size and number of the oxide particles can be measured, for instance, in the following manner.
  • An extracted replica is produced from a sample taken from a base steel plate, and it is observed at 20 or more visual fields, namely 1,000 ⁇ m 2 or more in terms of the total observation area, under a magnification of ⁇ 10,000 using an electron microscope.
  • the size of the particles are determined, for instance, by calculating circle-equivalent diameters of the particles based on micrographs of the particles.
  • the extracted replica may be produced from any portion from the surface layer to the thickness center of a steel plate. A lower magnification may be used if the oxide particles can be observed adequately.
  • the oxide particles form during the deoxidation process of molten steel.
  • the oxides forming at this stage are called primary oxides.
  • Ti-Al-Ca oxides form as the temperature of the molten steel falls during the stages of casting and solidification.
  • the oxides forming at these stages are called secondary oxides. Either primary oxides or secondary oxides may be used for the purpose of the present invention.
  • the present inventors proceeded with further studies for significantly increasing the effects of improving toughness by refining a HAZ structure yet more. As a result, they discovered that, when the reheated austenite grains were made finer by dispersing fine oxide grains in a great amount, an addition of B was very effective for suppressing the growth of ferrite at the grain boundaries and triple boundaries during the process in which a HAZ structure was formed.
  • C is an effective component for increasing steel strength and, as such, the lower limit of its content is set at 0.03%. Since its excessive addition remarkably deteriorates the weldability, HAZ toughness and so on of a steel material, the upper limit of its content is set at 0.18%.
  • Si is a component necessary for securing the strength of base metal, deoxidizing steel and so on, but the upper limit of its content is set at 0.5% in order to prevent the toughness of a HAZ from lowering through its hardening.
  • Mn is an effective component for securing the strength and toughness of base metal and, as such, it has to be added at 0.4% or more, but the upper limit of its content is set at 2.0% in order to control the toughness, cracking property and so on of welded joints within respective tolerable ranges.
  • Al is an important deoxidizing element and, for this reason, the lower limit of its content is set at 0.005%.
  • the upper limit of its content is set at 0.04%.
  • Ti is added at 0.005% or more for the purpose of forming Ti nitrides through the combination with N.
  • the HAZ toughness is lowered and, for this reason, the upper limit of its content is set at 0.03%.
  • B is an effective element, when it is in a solute state, for suppressing the growth of ferrite forming at the boundaries of reheated austenite grains and, for this reason, B of at least 0.0005% is added.
  • B When it is added in a great amount, however, the toughness of a steel material is deteriorated and, therefore, the upper limit of its content is set at 0.003%.
  • Cu is effective for enhancing the strength of a steel material but, when it is added in excess of 1.0%, the HAZ toughness is lowered and, therefore, the upper limit of its content is set at 1.0%.
  • Ni is effective for enhancing the strength and toughness of a steel material but, as the increase in its addition increases production costs, the upper limit of its content is set at 1.5%.
  • Nb is an effective element for enhancing the strength and toughness of base metal through the improvement of hardenability but, since its excessive addition deteriorates the toughness of a HAZ remarkably, the upper limit of its content is set at 0.04%.
  • V, Cr and Mo have the same effects as Nb does and, for this reason, the upper limits of their contents are set at 0.1, 0.6 and 0.6%, respectively.
  • REM has a deoxidizing strength in molten steel second to Ca and also a function of helping Ca form fine oxide grains, but its addition is more costly than the addition of Ca and, when added excessively, it forms coarse inclusions to deteriorate the toughness of a HAZ and a steel plate. For this reason, the upper limit of its content is set at 0.05%.
  • 50-kg class steels having the chemical compositions shown in Table 1 were produced for test purposes.
  • Steels 1 to 8 are invented steels and steels 9 to 14 are comparative steels.
  • the sample steels were melted in a converter and deoxidized during vacuum degassing treatment in an RH degasser.
  • the amount of solute oxygen in molten steel was controlled with Si before the addition of Ti, and then Ti and Al were added in this sequence for deoxidation.
  • the steels were cast into slabs 280 mm in thickness by continuous casting and then rolled into steel plates 45 mm in thickness through reheating and rolling.
  • the steel plates thus produced were welded through 1 pass of SEGARC welding.
  • the heat input was approximately 200 kJ/cm 2 .
  • Table 2 shows the composition of oxide particles, the number of the oxide particles 0.005 to 2.0 ⁇ m in diameter, the rolling conditions of the steel plates, the characteristics of base metal and the toughness of the HAZ.
  • a Charpy impact value for evaluating the HAZ toughness is the average value of 9 test pieces, each of the values being measured at the portion of a HAZ located 1 mm away from a fusion line.
  • steels 1 to 8 according to the present invention have excellent HAZ toughness compared with comparative steels: they are quite excellent in the HAZ toughness at -40°C, as the oxide particle size, the number of oxide particles and the amounts of their components are within the respective ranges specified in the present invention. It is also clear from the table that, among the steels according to the present invention, invented steels 3, 4, 5, 6, and 8 containing the oxide particles 0.1 to 2.0 ⁇ m in diameter within the range from 100 to 3,000 pieces/mm 2 , invented steels 2, 4, 5, 6, 7 and 8 having the oxide particles containing Mg of 1% or more, and invented steels 3, 4 and 5 having the oxide particles containing S of 1% or more are superior in the HAZ toughness to the other invented steels.
  • the content of Al in the oxide particles and the number of oxide particles are below the respective lower limits according to the present invention.
  • the Charpy test for evaluating the HAZ toughness was done at -40°C, and each of the impact values in the table is the average value of 9 test pieces, each of the values being measured at the portion of a HAZ located 1 mm away from a bond.
  • invented steels 17 to 24 have excellent HAZ toughness compared with comparative steels.
  • the density of the oxide particles 0.005 to 2.0 ⁇ m in diameter containing Ca and Al by respective prescribed contents is within the range from 100 to 3,000 pieces/mm 2 and, thanks to this, the austenite grain size of the HAZ structure of these steels is smaller compared with that of comparative steels, and the ferrite at the grain boundaries or triple boundaries of austenite grains is also small owing to the effect of B.
  • the Charpy absorbed energy value at -40°C of each of these steels far exceeds 50 J, which is the average absorbed energy value generally required of steel structures from the viewpoint of fracture mechanics, and thus the HAZ toughness is quite excellent, as seen in the table.
  • the density of the oxide particles 0.1 to 2.0 ⁇ m in diameter is 100 pieces/mm 2 or more and, as a consequence, the austenite grain size is relatively small compared with that of steels 19 and 22, and the Charpy absorbed energy value is high.
  • a HAZ toughness value is the average value of the results of Charpy tests at -40°C obtained by applying the Charpy tests to 9 test pieces, each of the values being measured at the portion of a HAZ located 1 mm away from the bond of the steel plates after the welding.
  • invented steels 32 to 39 have excellent HAZ toughness compared with comparative steels.
  • the density of the oxide particles 0.005 to 2.0 ⁇ m in diameter containing Ca and Al by respective prescribed contents is within the range from 100 to 3,000 pieces/mm 2 and, thanks to this, the austenite grain size of the HAZ structure of these steels is smaller compared with that of comparative steels, and the ferrite at the grain boundaries or triple boundaries of austenite grains is also small owing to the effect of B.
  • the Charpy absorbed energy value at -40°C of each of these steels far exceeds 50 J, which is the average value generally required of steel structures from the viewpoint of fracture mechanics, and thus the HAZ toughness is quite excellent, as seen in the table.
  • the density of the oxide particles 0.1 to 2.0 ⁇ m in diameter is 100 pieces/mm 2 or more and, as a consequence, the austenite grain size is relatively small compared with that of steels 34 and 37, and the Charpy absorbed energy value is high.
  • the present invention is a steel plate excellent in toughness at a welding joint even in high heat input welding or ultra-high heat input welding with a heat input of 200 kJ/cm 2 or more, and is applicable to general steel materials for welded structures used for ships, marine construction, medium and high-rise buildings, bridges and so on and also to material steel plates for pipes, bars, long steel products, hot-rolled steel sheets and the like.
  • a significant improvement in the toughness of a welded joint is obtained in any of these applications.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Nonmetallic Welding Materials (AREA)
EP04026201A 2000-02-10 2000-11-13 Stahl mit durch Schweissen beeinflusster Zone mit ausgezeichneter Zähigkeit Expired - Lifetime EP1520912B1 (de)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
JP2000033242A JP2001226739A (ja) 2000-02-10 2000-02-10 溶接熱影響部靭性に優れた鋼材
JP2000033242 2000-02-10
JP2000033241 2000-02-10
JP2000033241 2000-02-10
JP2000068210 2000-03-13
JP2000068210 2000-03-13
EP00974966A EP1262571B1 (de) 2000-02-10 2000-11-13 Stahl mit durch schweissen beeinflusster zone mit ausgezeichneter zähigkeit

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EP00974966A Division EP1262571B1 (de) 2000-02-10 2000-11-13 Stahl mit durch schweissen beeinflusster zone mit ausgezeichneter zähigkeit

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EP1520912A2 true EP1520912A2 (de) 2005-04-06
EP1520912A3 EP1520912A3 (de) 2005-04-27
EP1520912B1 EP1520912B1 (de) 2007-01-17

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EP04026201A Expired - Lifetime EP1520912B1 (de) 2000-02-10 2000-11-13 Stahl mit durch Schweissen beeinflusster Zone mit ausgezeichneter Zähigkeit
EP00974966A Expired - Lifetime EP1262571B1 (de) 2000-02-10 2000-11-13 Stahl mit durch schweissen beeinflusster zone mit ausgezeichneter zähigkeit

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EP (2) EP1520912B1 (de)
KR (1) KR100514667B1 (de)
DE (2) DE60033070T2 (de)
WO (1) WO2001059167A1 (de)

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WO2013007729A1 (en) * 2011-07-10 2013-01-17 Tata Steel Ijmuiden Bv Hot-rolled high-strength steel strip with improved haz-softening resistance and method of producing said steel

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JP3699077B2 (ja) * 2002-10-29 2005-09-28 株式会社日本製鋼所 溶接熱影響部の低温靭性に優れたクラッド鋼板用母材および該クラッド鋼板の製造方法
JP4972451B2 (ja) * 2007-04-20 2012-07-11 株式会社神戸製鋼所 溶接熱影響部および母材の低温靭性に優れた低降伏比高張力鋼板並びにその製造方法
JP4399018B1 (ja) 2008-07-15 2010-01-13 新日本製鐵株式会社 溶接熱影響部の靭性に優れた鋼板
US9403242B2 (en) 2011-03-24 2016-08-02 Nippon Steel & Sumitomo Metal Corporation Steel for welding
BR112014012265B1 (pt) * 2011-11-25 2018-12-18 Nippon Steel & Sumitomo Metal Corporation aço para soldagem
CN105008574B (zh) * 2013-03-12 2018-05-18 杰富意钢铁株式会社 多层焊接接头ctod特性优良的厚钢板及其制造方法
CN103320693B (zh) 2013-06-19 2015-11-18 宝山钢铁股份有限公司 抗锌致裂纹钢板及其制造方法
CN103320692B (zh) 2013-06-19 2016-07-06 宝山钢铁股份有限公司 超高韧性、优良焊接性ht550钢板及其制造方法

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JPH08158006A (ja) * 1994-12-06 1996-06-18 Kobe Steel Ltd 溶接熱影響部の靭性が優れた高強度鋼
JPH10183295A (ja) * 1996-12-19 1998-07-14 Nippon Steel Corp 大入熱溶接の熱影響部靭性の優れた鋼材およびその製造方法
JPH11229078A (ja) * 1998-02-16 1999-08-24 Kobe Steel Ltd 母材および大入熱溶接熱影響部の靱性に優れた高張力鋼板およびその製造方法
JP2000001738A (ja) * 1998-04-15 2000-01-07 Nippon Steel Corp 溶接熱影響部の靱性に優れた鋼板

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JPH08158006A (ja) * 1994-12-06 1996-06-18 Kobe Steel Ltd 溶接熱影響部の靭性が優れた高強度鋼
JPH10183295A (ja) * 1996-12-19 1998-07-14 Nippon Steel Corp 大入熱溶接の熱影響部靭性の優れた鋼材およびその製造方法
JPH11229078A (ja) * 1998-02-16 1999-08-24 Kobe Steel Ltd 母材および大入熱溶接熱影響部の靱性に優れた高張力鋼板およびその製造方法
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013007729A1 (en) * 2011-07-10 2013-01-17 Tata Steel Ijmuiden Bv Hot-rolled high-strength steel strip with improved haz-softening resistance and method of producing said steel
CN103649355A (zh) * 2011-07-10 2014-03-19 塔塔钢铁艾默伊登有限责任公司 具有改善的haz-软化抵抗性的热轧高强度钢带材及生产所述钢的方法
CN103649355B (zh) * 2011-07-10 2016-08-17 塔塔钢铁艾默伊登有限责任公司 具有改善的haz-软化抵抗性的热轧高强度钢带材及生产所述钢的方法

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DE60021919T2 (de) 2006-06-08
DE60033070D1 (de) 2007-03-08
EP1520912A3 (de) 2005-04-27
KR20020073579A (ko) 2002-09-27
DE60033070T2 (de) 2007-05-31
KR100514667B1 (ko) 2005-09-14
WO2001059167A1 (fr) 2001-08-16
EP1520912B1 (de) 2007-01-17
EP1262571A4 (de) 2003-03-26
EP1262571B1 (de) 2005-08-10
EP1262571A1 (de) 2002-12-04
DE60021919D1 (de) 2005-09-15

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