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
  • C22C38/40—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
  • 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
  • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
• • 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
  • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
  • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S148/00—Metal treatment
  • Y10S148/902—Metal treatment having portions of differing metallurgical properties or characteristics
  • Y10S148/908—Spring
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12431—Foil or filament smaller than 6 mils

Definitions

• the present invention relates to a stainless steel wire of small diameter having high mechanical characteristics, usable in particular for the manufacture of springs or elastomer reinforcement wires.
• fine drawn wires having very mechanical characteristics high, made of unstable austenitic stainless steel type 1.4310 (according to standards EN 10088 and Pr EN 10270.3) including chemical analysis comprises, by weight, from 16 to 19% of chromium, from 6 to 9.5% of nickel, at most 0.8 % molybdenum, at most 0.11% nitrogen and 0.05 to 0.15% carbon.
• the mechanical characteristics obtained for the drawn wire result from both the work hardening and the formation of martensite ⁇ 'generated by work hardening resulting from wire drawing.
• These wires can be used for the manufacture of springs which are obtained by shaping the wire then thermal relaxation treatment and hardening. This technique has at least one drawback which results from very significant consolidation during the wire drawing. Because of the importance of this consolidation, when the diameter of the wire is small, it cannot be obtained in several cycles alternating drawing and heat treatment of hyperemperance. This complicates manufacturing and increases its cost.
• fine drawn wires having characteristics very high mechanical properties, usable in particular for the manufacture of springs, made of austenitic stainless steel with secondary hardening by NiAl precipitation, type 1.4568 (according to EN 10088 and Pr EN 10270) the chemical analysis of which comprises, by weight, from 16 to 18% of chromium, from 6.5 to 7.8% nickel and 0.7-1.5% aluminum.
• This technique has the advantage of making it possible to manufacture the springs from a wire with mechanical characteristics significantly lower than desired mechanical characteristics for the spring, which facilitates the carrying out the shaping operation. Indeed, the characteristics final mechanical can be obtained by heat treatment of aging which causes precipitation hardening.
• this technique has the disadvantage of using steel grades containing easily oxidizable or nitriding elements which generate the formation of harmful inclusions for the fatigue strength of the springs, on the other hand these grades of steel lead, as in the previous case, to a very significant consolidation during wire drawing, which also requires way, a succession of cycles alternating drawing and treatment of hyper quenching.
• Document DE-A-2 338 282 describes a steel for the manufacture of very long wire, the composition of which overlaps that claimed.
• the object of the present invention is to remedy these drawbacks by offering a precipitation hardenable austenitic stainless steel wire, having, in the strain-hardened state before aging, a tensile strength greater than 2200 MPa for a diameter between 0.4 and 0.5 mm, greater than 2225 MPa for a diameter between 0.3 and 0.4 mm, greater than 2250 MPa for a diameter between 0.2 and 0.3 mm, greater than 2275 mm for a diameter less than 0.2 mm, and which is easy to draw or cold roll.
• This wire can be of round, oval or polygonal cross section, for example of triangular, square, rectangular or hexagonal section.
• its dimension is defined by its diameter
• its section is not round, its dimension is defined by the diameter of a wire whose section would have the same surface. In all cases, we will talk about the diameter of the wire.
• the subject of the invention is a stainless steel wire, of diameter less than 2 mm and of tensile strength greater than 2100 MPa, consisting of a steel whose chemical composition comprises, by weight: 0% ⁇ C ⁇ 0.03% 0% ⁇ Mn ⁇ 2% 0% ⁇ If ⁇ 0.5% 8% ⁇ Ni ⁇ 9% 17% ⁇ Cr ⁇ 18% 0% ⁇ Mo ⁇ 0.4% 3% ⁇ Cu ⁇ 3.5% 0% ⁇ N ⁇ 0.03% S ⁇ 0.01% P ⁇ 0.04% the remainder being iron and impurities resulting from processing.
• This wire can be used in particular to make a spring, make a cable or can constitute the core of an elastomer reinforcement wire.
• the invention also relates to a method for manufacturing the yarn according to the invention.
• the process consists of sourcing a wire rod of diameter greater than or equal to 5 mm made of an austenitic steel whose composition chemical complies with what is indicated above, to submit it to a hyperhardening treatment to give it an entirely austenitic structure, pickling and shaping it by cold plastic deformation, generally without intermediate heat treatment, or, for the smallest diameters, with an intermediate hyperemperation followed by a reduction in section greater than 300.
• the purpose of cold plastic deformation is to in particular, to reduce the section and, possibly, to give the section of the wire the desired shape (round, square, triangle, etc.).
• This plastic deformation can be made by wire drawing, rolling or any other manufacturing process of a wire by cold plastic deformation.
• the invention relates to an austenitic stainless steel, the chemical composition of which comprises, by weight: 0% ⁇ C ⁇ 0.03% 0% ⁇ Mn ⁇ 2% 0% ⁇ If ⁇ 0.5% 8% ⁇ Ni ⁇ 9% 17% ⁇ Cr ⁇ 18% 0% ⁇ Mo ⁇ 0.4% 3% ⁇ Cu ⁇ 3.5% 0% ⁇ N ⁇ 0.03% S ⁇ 0.01% P ⁇ 0.04% the remainder being iron and impurities resulting from processing.
• this steel exhibits the advantage of achieving high mechanical characteristics by drawing and structural hardening without the need for intermediate annealing, even for diameter reductions greater than 20 times.
• a wire is produced by hot rolling machine with a diameter greater than or equal to 5 mm which is subjected to a treatment hyperhardening consisting of heating to a temperature between 800 ° C and 1250 ° C followed by air cooling, or faster, in order to impart an entirely austenitic structure, then it is pickled.
• a treatment hyperhardening consisting of heating to a temperature between 800 ° C and 1250 ° C followed by air cooling, or faster, in order to impart an entirely austenitic structure, then it is pickled.
• the hyper-soaked and pickled wire rod thus obtained is then drawn until a diameter of less than 2 mm, in one or more stages of several passes each, without the need for any intermediate heat treatment, at month as long as the ratio of the initial section to the final section remains below 485.
• To manufacture the smallest diameters, especially the smaller diameters at 0.25 mm it may be necessary to make an intermediate overflow intended to restore the deformation capacity of the metal.
• the final work hardening i.e. carried out after the intermediate overheating, must correspond to a section reduction greater than 300 (final section / initial section ⁇ 1/300).
• This aging treatment consists of heating for a time between 5 min and 3 hours, at a temperature between 400 and 475 ° C It generates a hardening resulting from the precipitation of Cu ⁇ (c.f.c.) in a centered cubic structure ( ⁇ 'martensite induced by wire drawing deformation). This hardening is, all other things being equal, the higher the Martensite content is higher.
• the aging treatment can be performed either directly after drawing or after carrying out operations additional on the wire, for example after having shaped it to manufacture a spiral spring.
• drawn wire of 1 mm, 0.5 mm and 0.25 mm diameter was produced in accordance with the invention, starting with a machine wire 5.5 mm in diameter made up of a austenitic stainless steel, the chemical composition of which was as follows (in% by weight): VS Mn Yes Or Cr Mo Cu NOT S P 0.011 1.83 0.4 8.08 17.24 0.36 3.24 0.027 0.004 0.025
• the wire rod was hyper-soaked by reheating to 1080 ° C and water cooling then pickled.
• wires thus obtained were used to manufacture springs such as indicated above which have the advantage of having characteristics at least equal to those of springs manufactured in standard grade 1.4310, with a equal or even improved relaxation, while being simpler and less costly to to manufacture.
• the yarns according to the invention can also be used to make elastomeric reinforcing threads, for example example for making reinforcements of tires.
• These reinforcing threads comprise a core consisting of a drawn wire according to the invention coated, by example, by nickel plating and brass plating (this coating is intended to ensure good bond with rubber).

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Crystallography & Structural Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Heat Treatment Of Steel (AREA)
• Metal Extraction Processes (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Wire Processing (AREA)
• Cell Electrode Carriers And Collectors (AREA)
• Ropes Or Cables (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Treatment Of Steel In Its Molten State (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 1996
  • 1996-12-31 FR FR9616250A patent/FR2757878B1/fr not_active Expired - Fee Related
• 1997
  • 1997-12-03 EP EP97402907A patent/EP0851039B1/fr not_active Expired - Lifetime
  • 1997-12-03 AT AT97402907T patent/ATE204343T1/de active
  • 1997-12-03 DK DK97402907T patent/DK0851039T3/da active
  • 1997-12-03 ES ES97402907T patent/ES2162218T3/es not_active Expired - Lifetime
  • 1997-12-03 DE DE69706131T patent/DE69706131T2/de not_active Expired - Lifetime
  • 1997-12-03 PT PT97402907T patent/PT851039E/pt unknown
  • 1997-12-04 CA CA002223656A patent/CA2223656C/fr not_active Expired - Fee Related
  • 1997-12-08 TW TW086118434A patent/TW448233B/zh active
  • 1997-12-08 AU AU46921/97A patent/AU717911B2/en not_active Ceased
  • 1997-12-17 ZA ZA9711350A patent/ZA9711350B/xx unknown
  • 1997-12-18 US US08/993,658 patent/US6106639A/en not_active Expired - Lifetime
  • 1997-12-24 ID IDP973972A patent/ID19297A/id unknown
  • 1997-12-26 JP JP9368352A patent/JPH10204592A/ja not_active Withdrawn
  • 1997-12-30 BR BR9705615A patent/BR9705615A/pt not_active IP Right Cessation
  • 1997-12-30 KR KR1019970078938A patent/KR100487265B1/ko active IP Right Grant
  • 1997-12-30 CN CN97108588A patent/CN1076404C/zh not_active Expired - Fee Related

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