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
  • C22C38/18—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
  • 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

Definitions

• the invention relates to a method for producing non-magnetic drill string parts, in particular drill collars for exploration drilling, e.g. for oil and / or natural gas deposits, such as directional drilling or the like.
• the position and direction of the drilling is determined by magnetic measurement.
• the very precise magnetic field measurement which is undisturbed if suitable material is used is still preferred. Since such bores extend to ever greater depths, a particularly exact position determination is required.
• the drill string parts in particular those drill string parts which are arranged in the immediate vicinity of the measuring device, for example a forester probe, should only have magnetic anomalies to the smallest extent. So it is known, for example, if drill collars have a greater maximum compass deviation than + 1/4 0 , then they no longer meet the requirements or only in rare cases.
• these drill string parts must have a high mechanical strength, both for tensile and compressive stress, depending on whether a corresponding pressure is exerted on the drill head or whether the drill head is pulled out of the borehole becomes. Furthermore, these drill string parts are subject to a high level Torsional stress, because at least partially the rotary movement is carried out on the drill head. Furthermore, the alloys must be suitable for extruded parts for threaded connections, which must be detachable without "seizing up” even after long mechanical stress.
• Another very important criterion is the corrosion resistance, in particular the resistance to stress corrosion cracking, since such drill string parts are often exposed to strongly corrosive media, for example sodium chloride solutions and / or magnesium chloride solutions as well as hydrogen sulfide and the like.
• cerium-like drill string parts In addition to the criteria listed above, another essential prerequisite for the economic use of cerium-like drill string parts is that alloys are used which can be used over a long period of time and which are therefore not subject to the criterion of composition change due to material shortages or the like.
• AT-PS 214 466 describes the use of an amagnetic austenitic chromium-manganese steel alloy with in% by weight
• the present invention has set itself the goal of creating a process for the production of non-magnetic drill string parts which have a sufficiently high mechanical strength with little scatter, in particular by cold working, which at the same time ensures that no or only insignificant magnetizable islands remain in the drill string part , whereby the drill string parts should not have any permanent magnetization even with high magnetic fields.
• the remainder iron and optionally one or more of the following elements vanadium, boron and aluminum and production-related impurities are melted, solidified, subjected to at least 2 times, in particular 4 to 6 times hot working, optionally cooled and then at 1020 to 1070 ° C solution annealed, then, e.g. quenched in water and subjected to cold working consists essentially in that the cold working at a temperature above room temperature, in particular above 100 ° C and below about 700 ° C, in particular the Curie point of iron and with at least 5%, preferably at least 12%, deformation is carried out.
• Cold forging in particular stretch forging, has proven particularly useful as cold deformation, although different degrees of deformation can exist from the center to the edge region.
• a mechanical, in particular machining, is according to a further feature of present invention carried out after the cold forming, without this resulting in significant processing obstructions.
• the preferred limits for cold forming are at a temperature above 100 ° C. and below 550 ° C., in particular below the Curie point, as a result of which a particular resistance to intra- and intergranular stress corrosion cracking can be achieved.
• the test of magnetizability was carried out according to the procedure in accordance with EU-P 14 195, the prior to the test Collar was subjected to magnetization at 120 kA / m. No single measuring point could be determined that was above 0.02 microtesla.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Heat Treatment Of Steel (AREA)
• Hard Magnetic Materials (AREA)
• Earth Drilling (AREA)
• Heat Treatment Of Articles (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=3522989

Family Applications (1)

Country Status (5)

Cited By (7)

Families Citing this family (40)

Family Cites Families (6)

• 1985
  • 1985-06-25 AT AT0187985A patent/AT381658B/de not_active IP Right Cessation
• 1986
  • 1986-06-18 JP JP61140449A patent/JPS621815A/ja active Pending
  • 1986-06-19 DE DE8686890180T patent/DE3681641D1/de not_active Expired - Lifetime
  • 1986-06-19 EP EP86890180A patent/EP0207068B1/fr not_active Expired - Lifetime
• 1988
  • 1988-07-15 US US07/219,216 patent/US4919728A/en not_active Expired - Lifetime

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