EP0666332A1 - Acier a resistance a la traction elevee, a resistance a la fatigue et a aptitude au soudage superieures et procede de fabrication - Google Patents

Acier a resistance a la traction elevee, a resistance a la fatigue et a aptitude au soudage superieures et procede de fabrication Download PDF

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Publication number
EP0666332A1
EP0666332A1 EP94923079A EP94923079A EP0666332A1 EP 0666332 A1 EP0666332 A1 EP 0666332A1 EP 94923079 A EP94923079 A EP 94923079A EP 94923079 A EP94923079 A EP 94923079A EP 0666332 A1 EP0666332 A1 EP 0666332A1
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EP
European Patent Office
Prior art keywords
high tensile
weld
tensile steel
steel
fatigue strength
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.)
Withdrawn
Application number
EP94923079A
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German (de)
English (en)
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EP0666332A4 (fr
Inventor
Katsumi Kurebayashi
Shuji Aihara
Atsushi Seto
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Nippon Steel Corp
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Nippon Steel Corp
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Publication date
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Publication of EP0666332A1 publication Critical patent/EP0666332A1/fr
Publication of EP0666332A4 publication Critical patent/EP0666332A4/fr
Withdrawn legal-status Critical Current

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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
    • C22C38/06—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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0231—Warm rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling

Definitions

  • the present invention relates to a high tensile steel, having excellent fatigue strength at its weld and weldability, for shipbuilding, offshore structures, bridges, and the like and a process for producing the same.
  • a high-strength thin steel sheet having excellent fatigue properties in spot welding comprising C: not more than 0.3%, Si: 0.7 to 1.1%, Mn: not more than 2.0%, P: not more than 0.16%, and sol. Al: 0.02 to 0.1%, is disclosed.
  • Japanese Unexamined Patent Publication (Kokai) No. 3-264645 in order to attain good stretch-flange ability, fatigue properties, and resistance weldability by advantageously forming clean polygonal ferrite by Si, strengthening and improving the hardenability of a steel by B, a high-strength thin steel sheet having excellent stretch-flange ability and other properties, comprising C: 0.01 to 0.2%, Mn: 0.6 to 2.5%, Si: 0.02 to 1.5%, B: 0.0005 to 0.1%, and the like, is disclosed.
  • a very low carbon steel plate having a good spot weldability comprising C: not more than 0.006%, Mn: not more than 0.5%, Al: not more than 0.05%, and 0.001 to 0.100% in total of at least one member selected from Ti and/or Nb in a solid solution form exclusive of a nitride and a sulfide, is disclosed.
  • the thin steel sheets disclosed in Japanese Unexamined Patent Publication (Kokai) Nos. 62-10239 and 3-264645 are those of which the applications are mainly limited to base materials of wheels and disks for automobiles, and these steel sheets are quite different from steel plates used in shipbuilding and offshore structures, contemplated in the present invention, in applications, plate thickness, and use. Therefore, the findings associated with these steel sheets, as such, cannot be applied to the steel plates. Also regarding steel chemical compositions, the thin steel sheet disclosed in Japanese Unexamined Patent Publication (Kokai) No.
  • spot welding is a kind of resistance welding and used mainly in welding of thin steel sheets having a sheet thickness in the range of from about 0.5 to 3.5 mm after forming, for example, welding of thin steel sheets for members of automobiles.
  • spot welding portions to be welded are clamped between electrodes, and a large current is passed through the assembly for a short time.
  • the spot welding is different from arc welding used in welding of high-tensile steel plates, having a thickness of not less than 6 mm, as materials for shipbuilding, offshore structures, bridges, and the like in welding process, such as shape of electrodes, use or not of welding materials, and welding conditions, as well as in the shape of the weld, the weld residual stress, and the like, resulting in a difference in factors governing the fatigue strength between both the welding methods.
  • the fatigue strength could be improved in spot welding, the findings for spot welding, as such, cannot be applied to arc welding.
  • Japanese Examined Patent Publication (Kokoku) No. 3-56301 describes a spot weld of a very low carbon steel sheet and aims to regulate the hardness distribution at a spot weld.
  • B is added to refine the structure and prevent grain growth.
  • the upper limit of the amount of B added is set from the viewpoint of preventing a deterioration in material, and no study is made of the weldability.
  • An object of the present invention is to improve the fatigue strength of a weld of structural members, particularly a weld formed by arc welding.
  • Another object of the present invention is to improve the fatigue strength of structural members at their welds, particularly a weld heat affected zone (hereinafter referred to as "HAZ") of structural members by regulating the HAZ micro-structure of the as-welded structural members.
  • HAZ weld heat affected zone
  • a further object of the present invention is to provide a high-tensile steel plate having weldability good enough to stop weld cracking upon welding.
  • a further object of the present invention is to provide a process for producing a high-tensile steel plate which can attain the above object.
  • the present invention provides the following high-tensile steel plate.
  • the ferritic micro-structure fraction is higher than 20% and the bainite micro-structure fraction is lower than 80%, the fatigue cracking is likely to start from grain boundary ferrite or a soft ferritic micro-structure, such as ferrite side plate, so that the fatigue strength is not improved.
  • the hardenability is high, the martensitic micro-structure fraction is higher than 20% and the bainite micro-structure fraction is lower than 80%, the fatigue cracking starts at the grain boundary in the interface of a hard martensitic micro-structure. In this case as well, no improvement in fatigue strength can be attained.
  • the present invention by virtue of the above effects (1) and (2), provides a high-tensile steel sheet having improved fatigue strength and weldability, and further provides a high-tensile steel sheet having a higher fatigue strength by a combination of the effects (1) and (2) with the effect (3).
  • the addition of Cu and Mo is advantageous for further strengthening the ferritic micro-structure in HAZ by solid solution strengthening and, at the same time, improving the hardenability.
  • the addition of Nb is useful for inhibiting the recrystallization of ferrite in a temperature region which does not recrystallize during rolling and, at the same time, improving the hardenability
  • the addition of Ti is useful for inhibiting the coarsening of the grain diameter of austenite.
  • Ca and REM is useful for fixing sulfides causative of fatigue cracking and improving the ductility.
  • the present invention provides a high-tensile steel, characterized by comprising, by weight, C: 0.03 to 0.20%, Si: 0.6 to 2.0%, Mn: 0.6 to 2.0%, Al: 0.01 to 0.08%, N: 0.002 to 0.008%, and B: not more than 0.0020% with the balance consisting of Fe and unavoidable impurities.
  • the present invention provides a high-tensile steel comprising the above chemical compositions and further comprising at least one optional element selected from Cu: 0.1 to 1.5%, Mo: 0.05 to 0.5%, Ni: 0.1 to 3.0%, Cr: 0.1 to 1.0%, V: 0.01 to 0.10%, Nb: 0.005 to 0.06%, Ti: 0.005 to 0.05%, Ca: 0.0005 to 0.0050%, and REM: 0.0005 to 0.0050%. Furthermore, the present invention provides a high-tensile steel, having excellent fatigue strength at its weld and weldability, comprising the above elements, the bainite micro-structure fraction of HAZ being not less than 80%.
  • C is an element which serves to increase the strength of the base material, and the addition thereof in a large amount is preferred from the viewpoint of increasing the strength of the base material.
  • the upper limit of the C content is 0.20%.
  • the C content is excessively low, it becomes difficult to ensure the strength of the base material and, at the same time, the hardenability of the weld is deteriorated, leading to the formation of grain boundary pro-eutectoid ferrite harmful to the fatigue strength.
  • the C content is less than 0.03%, no micro-structure favorable for an improvement in fatigue strength can be formed. For this reason, the lower limit of the C content is 0.03%.
  • Si is a solid-solution strengthening element which does not significantly increase the hardenability. Si strengthens the micro-structure by solid-solution strengthening, inhibits dislocation motion, and inhibits fatigue cracking. Further, Si is known to reduce the stacking fault energy of the steel plate micro-structure and reduce the cross slip. Therefore, when plastic deformation is repeatedly applied to a steel plate, Si inhibits the crossing and localization of dislocation slip lines and enhances the reversibility of the plastic deformation to inhibit cracking. For this reason, Si is indispensable for improving the fatigue strength.
  • the Si content is less than 0.6%, the effect of solid-solution strengthening and stacking fault energy reduction is so small that an improvement in fatigue strength cannot be expected. For this reason, the lower limit of the Si content is 0.6%.
  • the Si is added in an amount exceeding 2.0%, the surface appearance is deteriorated due to the occurrence of red scale, increasing the fatigue cracking source and, at the same time, deteriorating the toughness. For this reason, the upper limit of the Si content is 2.0%.
  • Mn is an element which serves to increase the strength of the base material without a significant loss of toughness.
  • the lower limit of the Mn content is 0.6%.
  • Mn is added in an amount exceeding 2.0%, the toughness of the weld is lowered and, at the same time, the weldability and the ductility are deteriorated. For this reason, the upper limit of the Mn content is limited to 2.0%.
  • Al is necessary as a deoxidizing element, and when the amount of Al added is less than 0.01%, the deoxidizing effect cannot be expected. On the other hand, when Al is added in an amount exceeding 0.08%, large amounts of oxides and nitrides of Al are formed, deteriorating the toughness of the weld. For this reason, the upper limit of the Al content is 0.08%.
  • N when Ti is added, combines with Ti to inhibit the growth of austenite grains in HAZ. When N is less than 0.002%, this effect cannot be expected. For this reason, the lower limit of the N content is 0.002%. On the other hand, the addition of N in an excessive amount increases the amount of N in a solid solution form and lowers the HAZ toughness, so that the upper limit of the N content is 0.008%.
  • B serves to improve the hardenability of the HAZ micro-structure and, at the same time, to inhibit the formation of grain boundary ferrite as a fatigue crack origin.
  • weld cracking such as root cracking and toe cracking.
  • the effect is saturated when the B content is 0.0020%.
  • the upper limit of the amount of B added is 0.0020%.
  • the upper limit of the B content is 0.0005% from the viewpoint of having substantially no effect on the susceptibility to cold cracking.
  • P and S are impurity elements. The lower the contents of these elements, the better the results.
  • the upper limits of P and S each are preferably 0.020% when the toughness of the base material and the weld is taken into consideration in the case of P and when the toughness of the base material and the weld and, at the same time, a lowering in ductility in the through-thickness direction, are taken into consideration in the case of S.
  • Cu and Mo serve to improve the hardenability of the base material and HAZ. These elements are rather useful for reinforcing a ferrite matrix through solid-solution strengthening as with Si.
  • the lowering of stacking fault energy by Cu and Mo is smaller than that by Si, and the effect of Cu and Mo is not significant when the amounts of Cu and Mo added are less than 0.1% and less than 0.05%, respectively. For this reason, the lower limits of the Cu and Mo contents are 0.1% and 0.05%, respectively.
  • the amount of Cu and Mo added exceeds 1.5% and 0.5%, respectively, the hardenability is so high that martensite is formed to unfavorably lower the fatigue strength. For this reason, the upper limits of the Cu and Mo contents are 1.5% and 0.5%, respectively.
  • Ni, Cr, and V are elements which serve to improve the hardenability of the base material and HAZ.
  • the lower limits of the Ni, Cr, and V contents are respectively 0.1%, 0.1%, and 0.01% from the viewpoint of attaining the effects of these elements.
  • the addition of these elements in excessive amounts facilitates the formation of lower bainite and martensitic micro-structure and rather lowers the fatigue strength of the weld.
  • the upper limits of the Ni, Cr, and V contents are 3.0%, 1.0%, and 0.10%, respectively.
  • Nb has the effect of increasing the strength of the base material and, at the same time, improving the hardenability. Further, when controlled rolling and controlled cooling are applied in the production of a steel plate, the addition of Nb in an amount of not less than 0.005% is preferred for the purpose of increasing the temperature region which does not recrystallize to inhibit the recrystallization during rolling, thereby enabling controlled rolling to be carried out in a wide temperature region. The incorporation of Nb in a large amount, however, deteriorates the toughness of HAZ. For this reason, the upper limit of the Nb content is 0.06%.
  • Ti combines with N to form TiN which refines the HAZ micro-structure to improve the toughness of HAZ.
  • the addition of Ti in an amount of not less than 0.005% is necessary.
  • the addition of Ti in an amount exceeding 0.05% saturates the effect. For this reason, the lower limit and the upper limit of the Ti content are 0.005% and 0.05%, respectively.
  • Ca serves to fix sulfides as a fatigue crack source to improve the ductility. Further, it can prevent the occurrence of fatigue failure starting at the sulfides.
  • the amount of Ca added is not more than 0.0005%, this contemplated effect cannot be expected.
  • the Ca content exceeds 0.0050%, the toughness is lowered. For this reason, the lower limit and the upper limit of the Ca content are 0.0005% and 0.0050%, respectively.
  • REM serves to fix sulfides as a fatigue crack source to improve the ductility. Further, it can prevent the occurrence of fatigue failure starting at the sulfides.
  • REM's are rare earth elements which have the same effect. Among REM's, La, Ce, and Y are representative examples.
  • REM In order to attain the contemplated effect by the addition of REM, it is necessary to add REM in a total amount of not less than 0.0005%.
  • the addition of REM in a total amount exceeding 0.0050% however, saturates the effect and, at the same time, is not cost-effective. For this reason, the lower limit and the upper limit of the total amount of REM added are 0.0005% and 0.0050%, respectively.
  • Steels contemplated in the present invention are mainly high-tensile steels having a tensile strength of not less than 490 MPa, and steel plates having various strengths may be produced by applying the following production processes.
  • a steel ingot should be austenitized to 100% prior to hot rolling.
  • the steel ingot may be heated to the Ac3 point or above.
  • heating of the steel ingot to a temperature above 1250°C coarsens austenite grains to increase the grain diameter after rolling, deteriorating properties of the base material, such as strength and toughness. For this reason, the heating temperature is limited to between the Ar3 point and 1250°C.
  • a high-tensile steel can be stably provided at a low cost.
  • the hot rolling is terminated in a recrystallization temperature region and then spontaneously cooled.
  • lack of strength often occurs when the plate thickness is large or the amount of the added elements is small.
  • a production process using controlled rolling can provide a high-tensile steel having high strength and toughness.
  • introduction of a deformation band within austenite grains by rolling to increase the number of ferrite nuclei followed by spontaneous cooling is useful.
  • the introduction of the deformation band requires hot rolling in an unrecrystallization temperature region with a cumulative reduction ratio of not less than 40%.
  • the cumulative reduction ratio exceeds 90%, the toughness of the base material is unfavorably lowered. For this reason, the cumulative reduction ratio is limited to 40 to 90%.
  • a high-tensile steel can be provided which has higher strength than the steel prepared by the production process using controlled rolling alone.
  • cooling should be carried out at a rate of not less than 1°C/sec.
  • the cooling rate exceeds 60°C/sec, the increase in strength is saturated and the toughness is unfavorably lowered. For this reason, the cooling rate is limited to 1 to 60°C/sec.
  • the temperature at which the transformation is completed is 600°C or below
  • the cooling termination temperature is limited to 600°C to room temperature because a liquid at room temperature or above is usually employed as the cooling medium.
  • a high-tensile steel can be provided which has higher strength and toughness than the steel prepared by the production process using a combination of controlled rolling with accelerated cooling.
  • it is useful to recover the deformed micro-structure by decreasing the lattice defect density through the annihilation of dislocations and coalescence.
  • the tempering temperature is below 300°C, these effects cannot be expected.
  • the tempering temperature and time are limited to between 300°C and the Ac1 point and from 10 to 120 min, respectively.
  • the accumulative reduction ratio in recrystallization region is a reduction ratio defined by (h0 - h1)/h0
  • the accumulative reduction ratio in the unrecrystallization region is a reduction ratio defined by (h1 - h2)/h1
  • h0 represents slab thickness (mm)
  • h1 represents plate thickness (mm) after rolling in recrystallization temperature region or plate thickness (mm) before rolling in unrecrystallization temperature region
  • h2 represents plate thickness (mm) after rolling in the unrecrystallization temperature region.
  • the slabs were subjected to a series of steps wherein the slab was heated to between the Ac3 point and 1250°C, held at that temperature for 60 min, hot-rolled in a recrystallization temperature region, and then spontaneously cooled, or alternatively subsequently hot-rolled, without spontaneous cooling, in an uncrystallization temperature region with a cumulative reduction ratio of 40 to 90% and then spontaneously cooled, or alternatively forcibly cooled, without spontaneous cooling, at a cooling rate of 1 to 60°C/sec to a temperature in the range of from 600°C to room temperature and then spontaneously cooled, or further heated to between the 300°C and the Ac1 point to carry out tempering thereby preparing steel plates having a final thickness of 15 mm.
  • a T-shaped fillet weld fatigue specimen 1 as shown in Fig. 1.
  • numeral 2 designates a flat plate
  • numeral 3 designates a rib plate.
  • a fillet 4 is formed by both the plates.
  • the fillet was welded.
  • Numeral 5 designates a weld metal.
  • the level of the amount of Si added are three.
  • the steel 3 of the present invention prepared by controlled rolling with a cumulative reduction ratio of 40% in an unrecrystallization region has higher yield stress and tensile strength. Further, it was found that, although an increase in the amount of Si added gives rise to an increase in fatigue strength, it also increases the Charpy transition temperature, indicating that an optimal amount of Si added exists for putting the steel to practical use.
  • the steels 4 to 16 of the present invention with at least one member selected from Cu, Mo, Ni, Cr, Nb, V, Ti, B, Ca, and REM being added thereto also had higher fatigue strength than the steels 1 to 3 of the present invention by virtue of synergistic effect of the effect of Si, solid-solution strengthening by Cu and Mo, the effect of improving the hardenability by Ni, Cr, and V, the inhibition of recrystallization by Nb, the inhibition of coarsening of grains by Ti and N, the effect of inhibiting grain boundary ferrite by B, on the inhibition of sulfides by Ca and REM.
  • production processes used were ordinary rolling, controlled rolling, controlled rolling + accelerated cooling, controlled rolling + accelerated cooling + temper heat treatment.
  • the comparative steel 1 is a steel wherein the amount of Si added is smaller than the Si content range of the steel of the present invention.
  • the fatigue strength is improved when the amount of Si added falls within the Si content range of the steel of the present invention.
  • the fatigue strength is higher than that of the comparative steel 1.
  • the comparative steels 2 to 8 have excessively high hardenability and form a martensitic micro-structure to lower the bainite micro-structure fraction, so that the fatigue strength is lower than that of the steels of the present invention.
  • the fatigue strength while ensuring the weldability of steel plates, can be improved by adding particular elements to regulate the micro-structure of heat affected zone, and the use of the steel of the present invention can improve the reliability of welded structures with respect to fatigue failure.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
EP94923079A 1993-08-04 1994-08-04 Acier a resistance a la traction elevee, a resistance a la fatigue et a aptitude au soudage superieures et procede de fabrication. Withdrawn EP0666332A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP193350/93 1993-08-04
JP19335093 1993-08-04
PCT/JP1994/001297 WO1995004838A1 (fr) 1993-08-04 1994-08-04 Acier a resistance a la traction elevee, a resistance a la fatigue et a aptitude au soudage superieures et procede de fabrication

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Publication Number Publication Date
EP0666332A1 true EP0666332A1 (fr) 1995-08-09
EP0666332A4 EP0666332A4 (fr) 1995-12-13

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EP94923079A Withdrawn EP0666332A4 (fr) 1993-08-04 1994-08-04 Acier a resistance a la traction elevee, a resistance a la fatigue et a aptitude au soudage superieures et procede de fabrication.

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EP (1) EP0666332A4 (fr)
JP (1) JP3526576B2 (fr)
KR (1) KR0157540B1 (fr)
CN (1) CN1040555C (fr)
NO (1) NO951288L (fr)
WO (1) WO1995004838A1 (fr)

Cited By (9)

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WO1996041024A1 (fr) * 1995-06-07 1996-12-19 Ipsco Inc. Combinaison d'un moulin steckel et d'un appareillage de refroidissement accelere en ligne
DE19632370A1 (de) * 1996-08-10 1998-02-12 Thyssen Stahl Ag Hochleistungsschweißgeeigneter weichmagnetischer Stahl und seine Verwendung für Teile von Magnetschwebebahnen
EP1069198A1 (fr) * 1999-01-28 2001-01-17 Sumitomo Metal Industries, Ltd. Produit en acier destine a des pieces structurelles de machines
EP1072689A1 (fr) * 1999-07-30 2001-01-31 Usinor Procédé de fabrication de bandes minces en acier de type "TRIP" , et bandes minces ainsi obtenues
US6264767B1 (en) 1995-06-07 2001-07-24 Ipsco Enterprises Inc. Method of producing martensite-or bainite-rich steel using steckel mill and controlled cooling
US6309482B1 (en) 1996-01-31 2001-10-30 Jonathan Dorricott Steckel mill/on-line controlled cooling combination
EP1577412A1 (fr) * 2002-12-24 2005-09-21 Nippon Steel Corporation Tole d'acier de haute resistance presentant une excellente aptitude a l'ebarbage et une excellente resistance a l'adoucissement dans une zone affectee par la chaleur et son procede de production
US9975134B2 (en) 2011-03-15 2018-05-22 Samsung Display Co., Ltd. Deposition mask and method of manufacturing the same
EP4116445A1 (fr) * 2021-07-08 2023-01-11 SSAB Technology AB Produit d'acier laminé à chaud résistant aux intempéries et son procédé de fabrication

Families Citing this family (27)

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Publication number Priority date Publication date Assignee Title
KR100401167B1 (ko) * 1998-12-29 2003-12-31 주식회사 포스코 용접부인성이우수한베이나이트계고강도강및그제조방법
KR100431850B1 (ko) * 1999-12-28 2004-05-20 주식회사 포스코 저항복비를 갖는 고강도 강 및 그 제조방법
KR100431851B1 (ko) * 1999-12-28 2004-05-20 주식회사 포스코 고강도 구조용 강 및 그 제조방법
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US6264767B1 (en) 1995-06-07 2001-07-24 Ipsco Enterprises Inc. Method of producing martensite-or bainite-rich steel using steckel mill and controlled cooling
US5810951A (en) * 1995-06-07 1998-09-22 Ipsco Enterprises Inc. Steckel mill/on-line accelerated cooling combination
WO1996041024A1 (fr) * 1995-06-07 1996-12-19 Ipsco Inc. Combinaison d'un moulin steckel et d'un appareillage de refroidissement accelere en ligne
US6309482B1 (en) 1996-01-31 2001-10-30 Jonathan Dorricott Steckel mill/on-line controlled cooling combination
DE19632370A1 (de) * 1996-08-10 1998-02-12 Thyssen Stahl Ag Hochleistungsschweißgeeigneter weichmagnetischer Stahl und seine Verwendung für Teile von Magnetschwebebahnen
DE19632370C2 (de) * 1996-08-10 1998-07-02 Thyssen Stahl Ag Hochleistungsschweißgeeigneter weichmagnetischer Stahl und seine Verwendung für Teile von Magnetschwebebahnen
EP1069198A1 (fr) * 1999-01-28 2001-01-17 Sumitomo Metal Industries, Ltd. Produit en acier destine a des pieces structurelles de machines
EP1069198A4 (fr) * 1999-01-28 2002-02-06 Sumitomo Metal Ind Produit en acier destine a des pieces structurelles de machines
US6475305B1 (en) 1999-01-28 2002-11-05 Sumitomo Metal Industries, Ltd. Machine structural steel product
FR2796966A1 (fr) * 1999-07-30 2001-02-02 Ugine Sa Procede de fabrication de bandes minces en acier de type "trip" et bandes minces ainsi obtenues
EP1072689A1 (fr) * 1999-07-30 2001-01-31 Usinor Procédé de fabrication de bandes minces en acier de type "TRIP" , et bandes minces ainsi obtenues
US6328826B1 (en) 1999-07-30 2001-12-11 Usinor Method of fabricating “TRIP” steel in the form of thin strip, and thin strip obtained in this way
EP1577412A1 (fr) * 2002-12-24 2005-09-21 Nippon Steel Corporation Tole d'acier de haute resistance presentant une excellente aptitude a l'ebarbage et une excellente resistance a l'adoucissement dans une zone affectee par la chaleur et son procede de production
EP1577412A4 (fr) * 2002-12-24 2006-04-12 Nippon Steel Corp Tole d'acier de haute resistance presentant une excellente aptitude a l'ebarbage et une excellente resistance a l'adoucissement dans une zone affectee par la chaleur et son procede de production
US7749338B2 (en) 2002-12-24 2010-07-06 Nippon Steel Corporation High burring, high strength steel sheet excellent in softening resistance of weld heat affected zone and method of production of same
US9975134B2 (en) 2011-03-15 2018-05-22 Samsung Display Co., Ltd. Deposition mask and method of manufacturing the same
EP4116445A1 (fr) * 2021-07-08 2023-01-11 SSAB Technology AB Produit d'acier laminé à chaud résistant aux intempéries et son procédé de fabrication

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NO951288L (no) 1995-06-06
WO1995004838A1 (fr) 1995-02-16
CN1040555C (zh) 1998-11-04
JP3526576B2 (ja) 2004-05-17
KR0157540B1 (ko) 1998-11-16
KR950703661A (ko) 1995-09-20
EP0666332A4 (fr) 1995-12-13
CN1113391A (zh) 1995-12-13
NO951288D0 (no) 1995-04-03

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