Classifications

• • 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 of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/06—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
• • 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
  • 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
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
• • 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
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
• • 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
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
• • 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
  • C21D2261/00—Machining or cutting being involved
• • 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
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/002—Heat treatment of ferrous alloys containing Cr
• • 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
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/005—Heat treatment of ferrous alloys containing Mn
• • 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
  • C21D7/00—Modifying the physical properties of iron or steel by deformation

Definitions

• the invention relates to an austenitic, substantially ferrite-free Steel alloy.
• the invention comprises the use of an austenitic, im Essentially ferrite-free steel alloy.
• the invention relates to a process for the preparation of austenitic, substantially ferrite-free components, in particular Boring bars, for oil field technology.
• Austenitic alloys may be essentially ferrite-free, that is to say with a relative magnetic permeability ⁇ r smaller than 1.01. Thus, austenitic alloys can meet the above requirement and therefore be used principally for drill string components.
• a chosen austenitic material Minimum mechanical values Properties, in particular the 0.2% proof strength and tensile strength achieved and the dynamically changing loads occurring during drilling operation has grown, so in addition has a high permanent fatigue strength. Otherwise, for example, drill rods from corresponding Alloys the occurring during use high tensile and Compressive stresses and torsional stresses not or only for withstand a short operating time; undesirable rapid or premature Material failure is the result.
• Austenitic materials for drill string components tend to be high alloyed with nitrogen to high values of yield strength and tensile strength of components such as boring bars.
• alloys are economically favorable which, when solidified under atmospheric pressure to non-porous semi-finished product to lead.
• austenitic alloys are the high nitrogen content because rather rare, and it is consistently a stagnation under increased pressure required to achieve freedom from pores.
• One Melting and solidification under nitrogen pressure may also be necessary to to obtain enough nitrogen in the solidified material, if otherwise a insufficient nitrogen solubility is given.
• austenitic alloys which are suitable for use as Components of drill strings are provided, a good resistance against different types of corrosion.
• a good resistance against different types of corrosion In particular, is a high Resistance to pitting corrosion and stress corrosion cracking especially in chloride-containing media desired.
• Austenitic alloys are known in the art. which in each case meet some of these requirements, namely extensive freedom from ferrite, good mechanical properties, freedom from pores and high Corrosion resistance, meet.
• Another austenitic alloy is from the way already mentioned DE 196 07 828 A1 known.
• objects for the Offshore industry consisting of an austenitic alloy with (in Weight percent) 0.1% carbon, 8% to 15% manganese, 13% to 18% Chromium, 2.5% to 6% molybdenum, 0% to 5% nickel and 0.55% to 1.1% Nitrogen exist.
• Such objects are intended to be high mechanical Characteristics and a higher permanent alternating fatigue strength than objects have according to DE 39 40 438 C1.
• the disadvantage is one on the Alloy composition traceable low nitrogen solubility, why must be melted under pressure and allowed to solidify or even more complex powder metallurgical manufacturing processes are to be used.
• Austenitic alloy is described in AT 407 882 B.
• alloy has a high 0.2% proof stress, high tensile strength and a high permanent fatigue strength.
• Alloys according to AT 407 882 B are conveniently hot worked and at temperatures of 350 ° C. subjected to a second deformation to about 600 ° C.
• the alloys are suitable for a production of boring bars, which under a Drill bits in oil field technology also meet the high requirements in terms of static and dynamic load capacity over long periods in satisfactorily take into account.
• the invention takes on and sets itself the task of an austenitic To specify steel alloy which meltable at atmospheric pressure and to pore-free semi-finished is processed and which in good mechanical Properties, especially at high 0.2% proof stress, high tensile strength and high permanent fatigue strength, at the same time a high resistance both has against stress corrosion cracking as well as pitting corrosion.
• Another object of the invention is to provide uses for an austenitic, im Specify essentially ferrite-free alloy.
• an austenitic, substantially ferrite-free steel alloy is provided, which good mechanical properties, in particular high values of 0.2% Dehngrenze and the tensile strength and which at the same time a high Resistance to stress corrosion cracking and also against Pitting corrosion has.
• a temperature below the recrystallization temperature preferably below 600 ° C, in particular in the range of 300 ° C to 550 ° C.
• Carbon (C) can be contained in a steel alloy according to the invention up to 0.35% by weight. Carbon is an austenite former and works favorable in terms of high mechanical properties. With regard avoidance of carbidic precipitations, especially in larger dimensions, it is preferable to reduce the carbon content to 0.01% by weight. to adjust to 0.06 wt .-%.
• Silicon (Si) is provided in amounts up to 0.75% by weight and is used in the Main thing of a deoxidation of the steel. Higher contents than 0.75% by weight prove to be with regard to an education of intermetallic phases as disadvantageous. Silicon is also a ferrite former and therefore should a Silicon content to a maximum of 0.75 wt .-% be limited. Cheap and therefore It is preferred to use silicon in amounts of from 0.15% by weight to 0.30% by weight. provide, because in this content range sufficiently deoxidizing Effect is given at low contribution of silicon to ferrite formation.
• Manganese (Mn) is present in amounts of more than 19.0% by weight up to 30.0% by weight. intended. This element contributes significantly to a high Nitrogen solubility at. Non-porous materials from an inventive Steel alloys are therefore also when solidifying under atmospheric pressure produced. With regard to a nitrogen solubility of an alloy in the molten state as well as during and after solidification it is preferred to use manganese in contents of more than 20 wt .-%. manganese In addition, the austenite structure stabilizes especially at high degrees of deformation against the formation of Umformmartensit. With respect to a preferably good Corrosion resistance has an upper limit of manganese content 25.5 wt .-% result.
• Chromium (Cr) proves to be in levels of 17.0% by weight or more than necessary for a high corrosion resistance.
• chrome allows one Admixing large amounts of nitrogen.
• Higher contents than 24.0 wt .-% can adversely affect magnetic permeability because of chromium the ferrite-stabilizing elements counts.
• Particularly advantageous are chromium contents from 19.0% to 23.5%, preferably 20.0% to 23.0%. In these Held shows a common consideration of the inclination to the formation of chromium-containing precipitates and resistance to pitting and Stress corrosion cracking an optimum.
• Molybdenum (Mo) is an element used in a steel alloy according to the Invention essential for corrosion resistance in general and Pitting corrosion resistance in particular contributes, with the effect of molybdenum in a content range of more than 1.90 wt .-% by a Presence of nickel is enhanced.
• molybdenum on the one hand is an expensive element and on the other hand at higher levels tends to Formation of intermetallic phases increases, is a molybdenum content of 5.5 wt .-%, in preferred variants of the invention with 5.0 wt .-%, in particular 4.5 % By weight, limited.
• Nickel (Ni) has been found to contribute actively and positively to corrosion resistance in a content range greater than 2.50% to 15.0% by weight and in cooperation with the other alloying elements. In particular, and this is considered to be completely surprising from a professional point of view, in the presence of more than 2.50 wt .-% nickel is given a high stress corrosion cracking resistance. Contrary to the opinion outlined in relevant textbooks, with increasing nickel levels, stress corrosion cracking resistance of chromium-containing austenites in chloride-containing media decreases dramatically and is at a minimum at about 20 wt% (see, eg: AJ Sedriks, Corrosion of Stainless Steels, 2 ed. , John Wiley & Sons Inc., 1996, page 276), a high stress crack corrosion resistance can be achieved in a steel alloy according to the invention even with nickel contents of more than 2.50% to 15.0% by weight in chloride-containing media.
• nickel contents of at least 2.65% by weight, preferably at least 3.6% by weight, in particular 3.8% by weight to 9.8% by weight, nickel.
• Co Co
• Co can be up to 5.0% by weight for substitution of nickel be provided.
• Nickel as explained above, makes a high contribution to Corrosion resistance and is a strong Austenitchanner. In contrast, Although molybdenum also makes a significant contribution to Corrosion resistance, but is a ferrite. Therefore it is favorable if the nickel content is equal to or greater than the molybdenum content. Especially favorable in this context, if a nickel content more than 1.3 times, preferably more than 1.5 times a molybdenum content.
• Nitrogen (N) is required in amounts of at least 0.35 wt% to 1.05 wt% to ensure high strength. Further, nitrogen contributes to the corrosion resistance and is a strong austenite former, therefore, higher contents than 0.40 wt .-%, especially higher than 0.60 wt .-%, are favorable. On the other hand, as nitrogen content increases, nitrogen-containing precipitate formation tends to increase, for example, Cr 2 N. In advantageous variants of the invention, nitrogen content is therefore limited to 0.95% by weight, preferably 0.90% by weight.
• Boron (B) may be present at levels up to 0.005 wt% and favors in particular in a range of 0.0005 wt .-% to 0.004 wt .-% one Thermoformability of the composite material according to the invention.
• Copper (Cu) is tolerable in a steel alloy according to the invention in a content of less than 0.5 wt .-%. At levels of 0.04 wt.% To 0.35 wt.%, Copper proves to be quite advantageous in special drill bit applications, for example when boring bars come in contact with media such as hydrogen sulfide, especially H 2 S. Contents higher than 0.5% by weight promote precipitation formation and are disadvantageous for corrosion resistance.
• S Sulfur
• S Sulfur
• S is provided at levels up to 0.30% by weight. Larger contents as 0.1 wt .-% have a very favorable effect on processing a Steel alloy according to the invention, because a machining is relieved. If, however, pay attention to the highest corrosion resistance of the material, a sulfur content of 0.015 wt .-% is limited.
• the content of phosphorus (P) is less than 0.035 wt .-%.
• a phosphorus content is maximum 0.02 wt .-% limited.
• Vanadium (V), niobium (Nb), titanium (Ti) act in the steel in a sophisticated way and can be present for this purpose individually or in any combination, wherein a cumulative concentration of the elements present at most 0.85% by weight is. With regard to a grain-refining effect and avoidance of coarse precipitates of these strong carbide formers, it is beneficial if a sum concentration of the elements present more than 0.08% by weight and less than 0.45% by weight.
• the elements carry tungsten, Molybdenum, manganese, chromium, vanadium, niobium and titanium positive for solubility from nitrogen.
• the further object of the invention uses for an austenitic, im
• an austenitic, im To indicate essentially ferrite-free alloy is obtained by using a Steel alloy according to the invention as a material for components for the Oilfield technology achieved.
• the Component is a drill string part.
• the further object of the invention is also achieved by using an alloy according to the invention for stressed on train and pressure components, which with corrosive media, in particular a corrosive liquid such as saline Water, come in contact, reached.
• corrosive media in particular a corrosive liquid such as saline Water
• the method according to the invention is achieved by a process for the production of austenitic, substantially ferrite-free components, in particular boring bars, for oilfield technology, first containing a casting (in% by weight) up to 0.35% carbon to 0.75% silicon more than 19.0% to 30.0% manganese more than 17.0% to 24.0% chrome more than 1.90% to 5.5% molybdenum up to 2.0% tungsten up to 15.0% nickel to 5.0% cobalt 0.35% to 1.05% nitrogen to 0.005% boron up to 0.30% sulfur less than 0.5% copper less than 0.05% aluminum less than 0.035% phosphorus, where a sum content of nickel and cobalt is greater than 2.50%, and optionally one or more element (s) selected from the group consisting of vanadium, niobium and titanium, wherein the sum concentration of the selected elements is not more than 0.85 wt .-%, Remaining iron and manufacturing impurities is created, whereupon the casting is deformed into a semi-finished product at a temperature
• the component to be created is a boring bar
• Deformation degrees provide sufficient strength for uses and allow turning or peeling with reduced Tool wear.
• the semi-finished deformed blocks with water Ambient temperature quenched and finally at a temperature of 380 ° C to 420 ° C subjected to a second deformation step, wherein a Deformity 13% to 17%.
• the created objects were examined or further processed to drill rods.
• the alloys listed in Table 1 were examined for pitting corrosion resistance and stress corrosion cracking.
• the determination of the pitting corrosion resistance was carried out by measuring the pitting potential against a standard hydrogen electrode according to ASTM G 61.
• the stress corrosion cracking (SCC) was determined by determining the value of the SCC limit stress according to ATSM G 36.
• the value of the SCC cut-off voltage represents the externally applied maximum test voltage which a test sample can withstand for more than 720 hours in 155% boiling 45% MgCl 2 solution.
• Pitting potential E pit or SCC limit stress can even reach values corresponding to those of high alloyed Cr-Ni-Mo steels and nickel base alloys, with better strength properties as shown in Tables 4 and 5 at the same time. It is particularly favorable with respect to an SCC limit voltage, if a sum of molybdenum and nickel 4.7 wt .-% or more, in particular more than 6 wt .-%, is.
• articles made of the alloys 1 to 7 according to the invention have a relative magnetic permeability of ⁇ r ⁇ 1,005 and at room temperature permanent fatigue strengths of at least 400 MPa at 10 7 load changes.
• an alloy of the invention is optimal also as a material for fasteners or fasteners, such as Screws, nails, bolts or the like components, if this high mechanical loads as well as aggressive environmental conditions are exposed.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Heat Treatment Of Steel (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Earth Drilling (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=33315002

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (32)

Citations (11)

Family Cites Families (12)

• 2003
  • 2003-12-03 AT AT0193803A patent/AT412727B/de not_active IP Right Cessation
• 2004
  • 2004-11-17 DE DE502004002524T patent/DE502004002524D1/de not_active Expired - Lifetime
  • 2004-11-17 AT AT04450211T patent/ATE350505T1/de not_active IP Right Cessation
  • 2004-11-17 EP EP04450211A patent/EP1538232B1/fr not_active Expired - Lifetime
  • 2004-11-17 ES ES04450211T patent/ES2280936T3/es not_active Expired - Lifetime
  • 2004-12-01 NO NO20045271A patent/NO340359B1/no unknown
  • 2004-12-02 CA CA2488965A patent/CA2488965C/fr not_active Expired - Lifetime
  • 2004-12-02 US US11/001,061 patent/US7708841B2/en active Active
• 2010
  • 2010-03-16 US US12/725,229 patent/US7947136B2/en not_active Expired - Lifetime
• 2011
  • 2011-04-15 US US13/088,019 patent/US8454765B2/en not_active Expired - Lifetime

Patent Citations (12)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events