EP0849372B1 - Niederlegierter Baustahl mit aktiven Teilchen - Google Patents

Niederlegierter Baustahl mit aktiven Teilchen Download PDF

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Publication number
EP0849372B1
EP0849372B1 EP19970402979 EP97402979A EP0849372B1 EP 0849372 B1 EP0849372 B1 EP 0849372B1 EP 19970402979 EP19970402979 EP 19970402979 EP 97402979 A EP97402979 A EP 97402979A EP 0849372 B1 EP0849372 B1 EP 0849372B1
Authority
EP
European Patent Office
Prior art keywords
steel
zirconium
titanium
less
active particles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19970402979
Other languages
English (en)
French (fr)
Other versions
EP0849372A1 (de
Inventor
Dominique Kaplan
Louis Devillers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AG Der Dillinger Huettenwerke
Dillinger Huettenwerke AG
Original Assignee
AG Der Dillinger Huettenwerke
Dillinger Huettenwerke AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AG Der Dillinger Huettenwerke, Dillinger Huettenwerke AG filed Critical AG Der Dillinger Huettenwerke
Publication of EP0849372A1 publication Critical patent/EP0849372A1/de
Application granted granted Critical
Publication of EP0849372B1 publication Critical patent/EP0849372B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium

Definitions

  • the present invention relates to a steel with active particles which favor obtaining a fine ferritic grain.
  • thermomechanical treatments intended to refine the grain austenitic before transformation of austenite into ferrite. These treatments are, for example, normalization by reheating for a time not too long, at a temperature not too high above the temperature of transformation into austenite, or thermomechanical treatment with plastic deformation of steel in a temperature range such as, on the one hand the steel has an austenitic structure, and on the other hand that the grains hardened austenitics do not recrystallize as large grains.
  • This technique of grain refinement by heat treatments or thermomechanical is universally used. However, it presents the disadvantage of not being adapted to certain situations in which steel is subjected to thermal cycles imposed by circumstances particular use, the implementation processes or the manufacturing.
  • the object of the present invention is to remedy this drawback by providing a steel with improved grain refining ability ferritic and allowing to keep a fine grain, therefore properties of satisfactory ductility even when subjected to poor thermal cycles controlled resulting either from manufacturing conditions or from implementation, that is, finally, special circumstances of use. More specifically, the object of the invention is to provide a steel having, at the same time, a ferritic, ferrito-pearlitic or ferrito-bainitic structure, and a temperature "TK 28 J" below - 45 ° C.
  • the aluminum content and the titanium content satisfy the relationship (with Al and Ti expressed in% by weight): (Al - 0.0022) 2 / 1.6 2 + (Ti - 0.021) 2 / 13 2 ⁇ 10 -6
  • the content of this element is greater than 0.002%.
  • the active particles are then consisting of at least one mixed oxide of zirconium and titanium.
  • the active particles may also contain sulfide of manganese.
  • zirconium is added and the steel is poured less than 15 minutes after the addition of zirconium.
  • the inventors have found, in a new way, that so-called particles active, finely dispersed in steel, were germination sites for ferrite, not only by a local effect on the interfacial energy, but also because of the stresses generated in the metal around them. These stresses resulting from differences in the coefficient of expansion between the metal and active particles, appear during any thermal cycle to which steel is subjected, provided that it involves reheating to a sufficient temperature. Such thermal cycles are encountered in numerous circumstances of use, implementation or manufacture.
  • the inventors have also found in a new way that, in order for the stresses generated around the active particles have an effect significant, on the one hand, it is necessary that the deformations generated by these constraints are greater than 1.5%. Finally, they found that only particles of mixed titanium oxide and at least one other element taken from aluminum, silicon and zirconium, induce local deformation greater than 1.5%.
  • the inventors have found that the particles pure oxides of aluminum, silicon or titanium lead to deformations of less than 1.5%, than mixed oxide particles of aluminum and titanium, or the mixed particles of silicon oxides and titanium lead to deformations slightly greater than 1.5%, and, finally, that the particles of mixed zirconium and titanium oxide lead to deformations greater than 3.5%.
  • the particles of mixed zirconium and titanium oxides are sites of particularly effective ferrite germination. This efficiency is improved when the active particles contain a little sulfide of manganese associated with oxides.
  • the grains which have germinated on these active particles will be all the finer as the active particles will be more numerous.
  • the inventors have found that to obtain a significant effect, the number of active particles, counted on a micrographic section of 1 mm 2 , must be greater than 25.
  • the aluminum and titanium contents must satisfy the relationship: (Al - 0.0022) 2 / 1.6 2 + (Ti - 0.021) 2 / 13 2 ⁇ 10 -6
  • Ti - 0.021 titanium-quenched steels
  • the aluminum and titanium contents must satisfy the relationship: (Al - 0.0022) 2 / 1.6 2 + (Ti - 0.021) 2 / 13 2 ⁇ 10 -6
  • the steel must be produced according to the following production method: A non-deoxidized liquid steel containing less than 0.005% aluminum is produced, to which manganese is added before deoxidizing it under vacuum with carbon, manganese and silicon, so as to obtain an oxygen activity strictly less than 30 ppm , then the titanium is added either in the form of ferro-titanium or of ferro-silico-titanium, and, finally, the nuances are adjusted by adjusting the contents of alloying elements; when the steel must contain zirconium, this element is added at the end of production less than 15 minutes before casting, whether this is done continuously or in ingots;
  • steels 1 to 6 were manufactured according to the prior art, and 7 to 9 according to the invention, and their temperatures were measured “TK 28 J "(as defined above, ie measured after heating to 1300 ° C and rapid cooling).
  • Steel No. 8 also in accordance with the invention, differs from preceded by the presence of a small addition of zirconium which leads to the formation of active particles made up of mixed oxides of zirconium and titanium particularly effective in refining the microstructure.
  • This effect favorable results in a temperature "TK 28 J” 20 K lower by compared to the temperature "TK 28 J” of steel N ° 7 and, therefore, very below - 45 ° C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Claims (6)

  1. Verfahren zur Herstellung eines Stahls, dessen massebezogene chemische Zusammensetzung umfasst:
    0,05 % ≤ C ≤ 0,4 %
    0,2 % ≤ Mn ≤ 2,5 %
    0,05% ≤ Si ≤ 0,6%
    0% ≤ Ni ≤ 6%
    0% ≤ Cr ≤ 3%
    0% ≤ Mo ≤ 1,5%
    0% ≤ Cu ≤ 1 %
    0 % ≤ V ≤ 0,2 %
    0% ≤ Nb ≤ 0,1 %
    0% ≤ B ≤ 0,005%
    0 % ≤ S ≤ 0,02 %
    0,001 % ≤ Al ≤ 0,004%
    0,01% ≤ Ti ≤ 0,03%
    0% ≤ N ≤ 0,006 %
    gegebenenfalls Zirconium in Mengenanteilen unter 0,006 %,
    gegebenenfalls Seltenerdmetalle in Mengenanteilen unter 0,05 %,
    gegebenenfalls Calcium in Mengenanteilen unter 0,005 %,
    wobei der Rest aus Eisen und aus der Verarbeitung stammenden Verunreinigungen besteht,
    wobei der Stahl eine feine Dispersion von aktiven Partikeln enthält, die aus einem Mischoxid von Titan und mindestens einem Element bestehen, das unter Aluminium, Silicium und Zirconium ausgewählt ist, wobei die im Mikroschliff ausgezählte Anzahl der aktiven Partikel pro mm2 über 25 liegt,
    wobei das Verfahren die folgenden Schritt umfasst:
    Herstellung eines flüssigen, nicht desoxidierten Stahls, der weniger als, 0,005 % Aluminium enthält,
    Einarbeiten von Mangan,
    Desoxidation des Stahls mit Kohlenstoff, Mangan und Silicium im Vakuum, so dass eine Sauerstoffaktivität unter 30 ppm erhalten wird,
    Einarbeiten von Titan,
    anschließendes Feinen, und
    Gießen des Stahls in Form eines Halbzeugs.
  2. Verfahren nach Anspruch 1, wobei die chemische Zusammensetzung des Stahls so gewählt wird, dass der Gehalt an Aluminium und der Gehalt an Titan die folgende Beziehung erfüllt: (Al - 0,0022)2/1,62 + (Ti - 0,021)2/132 ≤ 10-6.
  3. Verfahren nach Anspruch 1, wobei der Stahl mehr als 0,002 % Zirconium enthält, wobei die aktiven Partikel aus mindestens einem Mischoxid von Zirconium und Titan bestehen, wobei nach dem Verfahren nach dem Zusatz von Titan Zirconium eingearbeitet wird, und wobei der Stahl weniger als 15 min nach dem Zusatz von Zirconium gegossen wird.
  4. Stahl, dessen massebezogene chemische Zusammensetzung umfasst:
    0,05 % ≤ C ≤ 0,4 %
    0,2% ≤ Mn ≤ 2,5%
    0,05 % ≤ Si ≤ 0,6 %
    0% ≤ Ni ≤ 6%
    0% ≤ Cr ≤ 3%
    0% ≤ Mo ≤ 1,5%
    0% ≤ Cu ≤ 1 %
    0% ≤ V ≤ 0,2%
    0% ≤ Nb ≤ 0,1%
    0% ≤ B ≤ 0005%
    0% ≤ S ≤ 0,02 %
    0,001 % ≤ Al ≤ 0,004 %
    0,01 % ≤ Ti ≤ 003%
    0 % ≤ N ≤ 0,006 %
    gegebenenfalls Zirconium in Mengenanteilen unter 0,006 %,
    gegebenenfalls Seltenerdmetalle in Mengenanteilen unter 0,05 %,
    gegebenenfalls Calcium in Mengenanteilen unter 0,005 %,
    wobei der Rest aus Eisen und aus der Verarbeitung stammenden Verunreinigungen besteht,
    wobei der Stahl eine feine Dispersion von aktiven Partikeln enthält, deren im Mikroschliff ausgezählte Anzahl pro mm2 über 25 liegt, dadurch gekennzeichnet, dass es sich bei den aktiven Partikeln um Mischoxide von Titan und einem oder mehreren Elementen handelt, die unter Silicium, Aluminium und Zirconium ausgewählt sind.
  5. Stahl nach Anspruch 4, dadurch gekennzeichnet, dass der Gehalt an Aluminium und der Gehalt an Titan die folgende Beziehung erfüllen: (Al - 0,0022)2/1,62 + (Ti - 0,021)2/132 ≤ 10-6.
  6. Stahl nach Anspruch 4, dadurch gekennzeichnet, dass er mehr als 0,002 % Zirconium enthält, und dadurch, dass die aktiven Partikel Mischoxide von Zirconium und Titan sind.
EP19970402979 1996-12-19 1997-12-10 Niederlegierter Baustahl mit aktiven Teilchen Expired - Lifetime EP0849372B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9615592 1996-12-19
FR9615592A FR2757542B1 (fr) 1996-12-19 1996-12-19 Acier de construction faiblement allie a particules actives

Publications (2)

Publication Number Publication Date
EP0849372A1 EP0849372A1 (de) 1998-06-24
EP0849372B1 true EP0849372B1 (de) 2003-10-08

Family

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Family Applications (1)

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EP19970402979 Expired - Lifetime EP0849372B1 (de) 1996-12-19 1997-12-10 Niederlegierter Baustahl mit aktiven Teilchen

Country Status (3)

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EP (1) EP0849372B1 (de)
DE (1) DE69725414T2 (de)
FR (1) FR2757542B1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2196845C2 (ru) * 1999-04-27 2003-01-20 Открытое акционерное общество "Ижорские заводы" Сталь

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62109948A (ja) * 1985-11-07 1987-05-21 Kawasaki Steel Corp 溶接用高靭性鋼
JPH0757886B2 (ja) * 1988-07-14 1995-06-21 新日本製鐵株式会社 溶接熱影響部靭性の優れたＣｕ添加鋼の製造法
JPH02194115A (ja) * 1989-01-23 1990-07-31 Nippon Steel Corp チタン酸化物を含有する溶接部靭性の優れた低温用高張力鋼の製造法
JPH0642979B2 (ja) * 1989-02-20 1994-06-08 新日本製鐵株式会社 チタン酸化物を含有する溶接・低温用高張力鋼の製造法
JP2661845B2 (ja) * 1992-09-24 1997-10-08 新日本製鐵株式会社 含オキサイド系耐火用形鋼の制御圧延による製造方法
JP2760713B2 (ja) * 1992-09-24 1998-06-04 新日本製鐵株式会社 耐火性及び靱性の優れた制御圧延形鋼の製造方法
JP2965813B2 (ja) * 1993-03-26 1999-10-18 新日本製鐵株式会社 降伏点制御圧延形鋼
JP2944843B2 (ja) * 1993-04-07 1999-09-06 新日本製鐵株式会社 Ｔｉ−Ａｌ複合系酸化物が分散した溶接部の靭性に優れた溶接構造用鋼の製造方法

Also Published As

Publication number Publication date
EP0849372A1 (de) 1998-06-24
FR2757542A1 (fr) 1998-06-26
DE69725414T2 (de) 2004-08-19
FR2757542B1 (fr) 1999-01-15
DE69725414D1 (de) 2003-11-13

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