EP0577898B1 - Rostfreies nicht-magnetisches Stahl mit hohem Mangan- und Chromgehalt, mit hohe Widerstandsfähigkeit gegen Spannungskorrosion und verwendbar für Bohrausrüstungen sowie Verfahren zur Herstellung von Stangen aus diesen Stahl - Google Patents

Rostfreies nicht-magnetisches Stahl mit hohem Mangan- und Chromgehalt, mit hohe Widerstandsfähigkeit gegen Spannungskorrosion und verwendbar für Bohrausrüstungen sowie Verfahren zur Herstellung von Stangen aus diesen Stahl Download PDF

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Publication number
EP0577898B1
EP0577898B1 EP92401946A EP92401946A EP0577898B1 EP 0577898 B1 EP0577898 B1 EP 0577898B1 EP 92401946 A EP92401946 A EP 92401946A EP 92401946 A EP92401946 A EP 92401946A EP 0577898 B1 EP0577898 B1 EP 0577898B1
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EP
European Patent Office
Prior art keywords
steel
bar
ingot
temperature
corrosion
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.)
Revoked
Application number
EP92401946A
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English (en)
French (fr)
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EP0577898A1 (de
Inventor
Jean Bourrat
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.)
Aubert and Duval SA
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Aubert and Duval SA
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Application filed by Aubert and Duval SA filed Critical Aubert and Duval SA
Priority to DE1992625065 priority Critical patent/DE69225065T2/de
Publication of EP0577898A1 publication Critical patent/EP0577898A1/de
Application granted granted Critical
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/16—Drill collars
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese

Definitions

  • the present invention relates to non-magnetic stainless steels with high mechanical resistance characteristics, as well as the parts made of these steels and their manufacturing processes.
  • the invention typically applies to the production of parts for the oil drilling industry, in particular for offshore drilling ( off-shore ), such as " drill-collars” , which are parts non-magnetic mechanics placed at the head of the drilling train allowing the entire column to be guided, the latter being made up, for the rest, of elements made of conventional ferromagnetic steel.
  • offshore drilling off-shore
  • drill-collars parts non-magnetic mechanics placed at the head of the drilling train allowing the entire column to be guided, the latter being made up, for the rest, of elements made of conventional ferromagnetic steel.
  • the magnetic permeability of these parts must be as low as possible, in any case less than 1.01 and generally less than 1.005.
  • This essential physical property allows to guide the drill string in its non-rectilinear progression in the medium to be drilled, by combining the field component magnetic created by a magnet housed in the drill collar with that of the Earth's magnetic field.
  • This property of non-magnetism is also required for parts other than drill collars, in particular "stabilizers" or various other measuring equipment or control less mechanically critical, but before nevertheless be made of non-magnetic steel.
  • the second requirement is the ability to withstand the stresses to which these parts are subjected during work, whether these stresses are in bending, in traction or in torsion.
  • imposed minima ( SPEC 7 of May 28, 1984) have been established by the API (American Petroleum Institute), providing in particular, in longitudinal direction, a yield strength E p0,2 in traction of at least 760 MPa for diameters between 79 mm (3 1/8 ") and 175.0 mm (6 7/8") and at least 690 MPa for diameters between 178 mm (7 ") and 254 mm ( 10 ").
  • a metal subject to intergranular corrosion due to precipitation of chromium carbides and carbonitrides in the joints of grains which, associated with a depleted chromium zone on the part and on the other side of the joint, "sensitizes the metal to intergranular corrosion) is also sensitive to the stress corrosion mechanism, which has its source in the grain boundaries, and this mechanism can combine very quickly with corrosion in transgranular mode.
  • Corrosion resistance must therefore be adapted to the various environments in which tools are likely to work made using these steels.
  • the route generally followed consists rather of making steels manganese-chromium-based austenitics containing amounts significant (0.2 to 0.6%) of nitrogen, the hardening element par excellence austenites and also generator and stabilizer of this phase.
  • Such a steel is for example described in EP-A-0 277 065, which describes a steel comprising mass proportions of at most 0.06% carbon, 19 to 26% manganese, 7 to 13% chromium, about 0.3% nitrogen and 0.6% silicon, less than 0.2% nickel and less than 0.1% molybdenum.
  • this steel is hardened by hot working.
  • This treatment was carried out either by shot peening or by hammering, this operation having the effect of compressing the treated surface to a certain depth (up to 1.5 mm for shot blasting and up to 5 mm for hammering), thus allowing the part to properly resist stress corrosion at the place thus treated.
  • the present invention provides a steel grade which remedies the aforementioned drawbacks and which, while offering the properties required magnetism and high mechanical performance, either by nature - and not after surface treatment - resistant stress corrosion and intergranular corrosion. In this way, the parts produced can be used naked, directly after shaping, without the need to provide a surface and local treatment of sensitive surfaces.
  • the invention proposes a non-magnetic steel grade which, once hardened, has the mechanical properties of a cold-worked steel but also withstands stress corrosion and to intergranular corrosion than a hyperhardened metal, not hardened.
  • the invention also proposes, as will be seen, a method which lends itself perfectly to the realization of any non-magnetic piece and with a high elastic limit, in particular non-magnetic drill swabs and similar parts (stabilizers, in particular), which are typical pieces which must have these characteristics and which, moreover, are the most difficult to manufacture given their very large dimensions.
  • the steel of the invention is a steel with an austenitic structure characterized by the respective mass proportions of the following elements: carbon ⁇ 0.025%, preferably ⁇ 0.020%, manganese 15 to 25%, chromium 10 to 15%, nickel ⁇ 0.25%, molybdenum 1.0 to 1.3%, nitrogen 0.30 to 0.50%, silicon ⁇ 1.0%. the balance being iron and residual impurities.
  • the transformations applied to the bar work harden it, preferably with a wrinkling factor of at least 1.5.
  • the invention allows the production of long non-magnetic hardened steel bars (typically, greater than 2 or 3 m) presenting over their entire length homogeneous mechanical characteristics, in particular characteristics meeting the values imposed by the recommendations API mentioned above.
  • the present invention therefore also relates, by way of new industrial product, a hardened non-magnetic steel bar length greater than 2.5 m, especially for equipment of drilling, presenting, over its entire length and homogeneously, a mechanical resistance, in transverse direction, to tensile failure at least 830 MPa and insensitivity to corrosion intergranular and stress corrosion.
  • a steel grade with the following composition is produced, using techniques which are in themselves conventional: carbon ⁇ 0.020%, manganese 15 to 25%, chromium 10 to 15%, nickel ⁇ 0.25%, molybdenum 1.0 to 1.3%, nitrogen 0.30 to 0.50%, silicon ⁇ 1.0%, sulfur ⁇ 0.010%, phosphorus ⁇ 0.025%. the balance being iron and residual impurities.
  • the molybdenum content is chosen to be high because, although that, as with nickel, a high molybdenum content decreases resistance to stress corrosion, the presence of this element is a factor of resistance to pitting and corrosion cavernous.
  • the properties of the shade according to the invention allow indeed to obtain such a high resistance to stress corrosion that the negative impact of molybdenum on this resistance becomes negligible.
  • drill rods are tubular parts, threaded in their two ends and axially bored over its entire length to a diameter between 50.8 and 76.2 mm (this value depending on the diameter outside).
  • the starting metal consists of an octagonal ingot of 10 t, with an average section of around 60 dm 2 (the extreme ingot weights corresponding to the smallest and the largest diameters are approximately 3.5 and 10 t respectively).
  • This ingot is first heated in a gas oven to a temperature between 1240 and 1280 ° C for a period of time between 16 and 24 hours.
  • the ingot thus made uniform in temperature is then fed and subjected to a first consistent thermomechanical transformation in a roughing operation by press stretching (press 4500 t), to obtain an octagonal 290 mm blank on dishes.
  • This operation which lasts approximately one hour, must necessarily lead to an octagonal bar whose length is less than 6 m in order to subsequently apply a minimum wrought 1.5 on the finished product.
  • thermomechanical transformation is carried out, starting with a second heating up to a temperature (in the case of this example) from 980 to 1000 ° C, the temperature being depending on the section of the blank and the diameter of the workpiece.
  • This heating is carried out in a gas oven for 8 hours approximately, in order to obtain a uniform temperature over the entire length of the bar and over the entire extent of the section.
  • the two blanks are then subjected, in a single operation, to rapid forging in stamps with simultaneous dressing on the 4500-ton press, which makes it possible to obtain a bar of approximately 230 mm in diameter and 10 m in length.
  • the bar is returned in end of operation to forge the extreme part previously held in the bits. During this operation, the temperature drops in skin up to 750 ° C.
  • the bar is then placed on the ground, cooled as quickly as possible, then the training is completed.
  • thermomechanical forming operations are then completed.
  • the drill rods thus produced proved to be perfectly meet corrosion resistance requirements as well as those of mechanical strength.
  • test pieces corrosion samples taken and placed in a sulfocupric medium boiling showed no beginning of intergranular corrosion.
  • a ring test piece ( C-Ring test piece according to ASTM G 38) was stressed either in constant deformation or in constant stress and placed in test environments capable of causing stress corrosion, the most conventional of which is a CL 2 Mg, 6H 2 O 44% medium boiling at 154 ° C (test according to ASTM G 36), or else in a test medium for delayed corrosion by hydrogen, the most common of which is a ClNa medium at 50 g / l buffered with glacial acetic acid at pH 3 and saturated with H 2 S at room temperature (test according to NACE TM 01-77).
  • test specimens constrained to stresses equal to 80% of the elastic limit E p 0.2, showed no rupture after 720 h of test, these tests having even been extended without further consequences until 1000 h.

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  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Fluid Mechanics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)
  • Forging (AREA)

Claims (10)

  1. Nicht magnetischer, nichtoxidierbarer Stahl mit austenitischer Struktur auf Mangan-Chrom-Basis, gekennzeichnet durch die jeweiligen Massenverhältnisse der folgenden Elemente: Kohlenstoff ≤ 0,025% Mangan 15 bis 20 % Chrom 10 bis 15 % Nickel < 0,25 % Molybdän 1,0 bis 1,3 % Stickstoff 0,30 bis 0,50 % Silicium < 1,0%,
    wobei der Rest aus Eisen und restlichen Unreinheiten besteht.
  2. Stahl gemäß Anspruch 1, bei dem der Anteil des Kohlenstoffs zumindest gleich 0,020 % ist.
  3. Herstellungsverfahren für einen Stab, gekennzeichnet durch die folgenden Schritte:
    Erschmelzung eines Ausgangsblockes aus einem Stahl gemäß Anspruch 1,
    erste homogene Erhitzung bei einer höheren Temperatur als der Rekristallisationstemperatur des Stahls,
    Vorformen des Stabes durch Warmziehen des Blockes,
    erstes Abkühlen auf Umgebungstemperatur,
    zweite homogene Erhitzung
    Formgebung des Stabes durch Schmieden und Preßwalzen,
    zweites Abkühlen auf Umgebungstemperatur, und
    Endbearbeitung.
  4. Verfahren gemäß Anspruch 3, bei dem die erste Erhitzung bei einer Temperatur zwischen 1240 und 1280°C stattfindet.
  5. Verfahren gemäß Anspruch 3, bei dem die zweite Erhitzung bei einer Temperatur zwischen 800 und 1000°C stattfindet.
  6. Verfahren gemäß Anspruch 3, bei dem die Bearbeitungen, denen der Stab unterzogen wird, diesen mit einem Schweißfaktor von zumindest 1,5 kaltverfestigen.
  7. Verfahren gemäß Anspruch 3, das außerdem nach dem Vorformungsschritt einen zusätzlichen Schritt zum Entfernen der Enden des Blockes aufweist.
  8. Verfahren gemäß einem der Ansprüche 3 bis 7, bei dem nach dem Vorformungsschritt oder, gegebenenfalls dem Schritt zum Entfernen der Enden des Blockes, ein zusätzlicher Schritt der Unterteilung des Blockes oder bzw. des verbleibenden Teils des Blockes in eine Vielzahl von verschiedenen Längen vorgesehen ist, wobei jede Länge dann einzeln in den aufeinanderfolgenden Schritten des Verfahrens behandelt wird.
  9. Nicht magnetischer Stahlstab gemäß Anspruch 1 oder 2, der mit größerer Länge als 2,5 m kaltverfestigt ist, insbesondere für Bohrausrüstungen, dadurch gekennzeichnet, daß er auf seiner gesamten Länge in homogener Weise eine Elastizitätsgrenze Ep0,2 in Längsrichtung, die zumindest gleich 760 MPa für Endprodukte mit Durchmessern zwischen 79 und 175 mm und gleich 690 MPa für Endprodukte mit Durchmessern zwischen 178 und 254 mm ist, und eine Unempfindlichkeit gegenüber der interkristallinen Korrosion und der Spannungskorrosion aufweist.
  10. Nicht magnetischer Stahlstab gemäß Anspruch 9, dadurch gekennzeichnet dass dieser Stab durch Einbringung des Verfahrens gemäß einem der Ansprüche 3 bis 8 verarbeitet wurde.
EP92401946A 1991-02-14 1992-07-07 Rostfreies nicht-magnetisches Stahl mit hohem Mangan- und Chromgehalt, mit hohe Widerstandsfähigkeit gegen Spannungskorrosion und verwendbar für Bohrausrüstungen sowie Verfahren zur Herstellung von Stangen aus diesen Stahl Revoked EP0577898B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE1992625065 DE69225065T2 (de) 1992-07-07 1992-07-07 Rostfreies nicht-magnetisches Stahl mit hohem Mangan- und Chromgehalt, mit hohe Widerstandsfähigkeit gegen Spannungskorrosion und verwendbar für Bohrausrüstungen sowie Verfahren zur Herstellung von Stangen aus diesen Stahl

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR9101743A FR2672904B1 (fr) 1991-02-14 1991-02-14 Acier inoxydable amagnetique a base manganese-chrome resistant a la corrosion sous contrainte, procede de fabrication d'une barre en acier amagnetique de grande longueur.

Publications (2)

Publication Number Publication Date
EP0577898A1 EP0577898A1 (de) 1994-01-12
EP0577898B1 true EP0577898B1 (de) 1998-04-08

Family

ID=9409716

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92401946A Revoked EP0577898B1 (de) 1991-02-14 1992-07-07 Rostfreies nicht-magnetisches Stahl mit hohem Mangan- und Chromgehalt, mit hohe Widerstandsfähigkeit gegen Spannungskorrosion und verwendbar für Bohrausrüstungen sowie Verfahren zur Herstellung von Stangen aus diesen Stahl

Country Status (3)

Country Link
EP (1) EP0577898B1 (de)
AT (1) ATE164888T1 (de)
FR (1) FR2672904B1 (de)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2672904B1 (fr) * 1991-02-14 1993-05-07 Aubert & Duval Acieries Acier inoxydable amagnetique a base manganese-chrome resistant a la corrosion sous contrainte, procede de fabrication d'une barre en acier amagnetique de grande longueur.
FR2744379A1 (fr) * 1996-02-07 1997-08-08 Smf Int Procede de traitement mecanique d'un produit de forme allongee en acier austenitique amagnetique et en particulier d'une masse-tige pour forage petrolier
DE19813459A1 (de) 1998-03-26 1999-09-30 Mettler Toledo Gmbh Elastisch verformbares Bauteil und Verfahren zu seiner Herstellung
AT407882B (de) 1999-07-15 2001-07-25 Schoeller Bleckmann Oilfield T Verfahren zur herstellung eines paramagnetischen, korrosionsbeständigen werkstoffes u.dgl. werkstoffe mit hoher dehngrenze, festigkeit und zähigkeit
JP4538966B2 (ja) * 2001-02-05 2010-09-08 大同特殊鋼株式会社 高強度高耐食非磁性ステンレス鋼
JP4379804B2 (ja) * 2004-08-13 2009-12-09 大同特殊鋼株式会社 高窒素オーステナイト系ステンレス鋼
CN101745786B (zh) * 2009-12-31 2012-03-14 上海新闵重型锻造有限公司 一种给水接管及二次侧人孔及其锻造方法
CN108866424A (zh) * 2018-07-13 2018-11-23 广州广钢新材料股份有限公司 一种耐腐蚀螺纹钢及其制备方法
CN110117746B (zh) * 2019-02-01 2021-07-27 上海加宁新材料科技有限公司 一种高性能无磁不锈钢的制造方法

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB779591A (en) * 1954-09-02 1957-07-24 Ford Motor Co Austenitic iron-base alloy
AT214466B (de) * 1959-06-04 1961-04-10 Schoeller Bleckmann Stahlwerke Stahllegierungen zur Herstellung von Schwerstangen für Tiefbohrgestänge
BE754614A (fr) * 1969-12-27 1971-01-18 Nisshin Steel Co Ltd Aciers inoxydables austenitiques
US4450008A (en) * 1982-12-14 1984-05-22 Earle M. Jorgensen Co. Stainless steel
AT381658B (de) * 1985-06-25 1986-11-10 Ver Edelstahlwerke Ag Verfahren zur herstellung von amagnetischen bohrstrangteilen
FR2672904B1 (fr) * 1991-02-14 1993-05-07 Aubert & Duval Acieries Acier inoxydable amagnetique a base manganese-chrome resistant a la corrosion sous contrainte, procede de fabrication d'une barre en acier amagnetique de grande longueur.

Also Published As

Publication number Publication date
FR2672904A1 (fr) 1992-08-21
EP0577898A1 (de) 1994-01-12
FR2672904B1 (fr) 1993-05-07
ATE164888T1 (de) 1998-04-15

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