WO2019240127A1 - Wire rod for stainless steel wire, stainless steel wire and manufacturing method therefor, and spring component - Google Patents

Wire rod for stainless steel wire, stainless steel wire and manufacturing method therefor, and spring component Download PDF

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Publication number
WO2019240127A1
WO2019240127A1 PCT/JP2019/023091 JP2019023091W WO2019240127A1 WO 2019240127 A1 WO2019240127 A1 WO 2019240127A1 JP 2019023091 W JP2019023091 W JP 2019023091W WO 2019240127 A1 WO2019240127 A1 WO 2019240127A1
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Prior art keywords
steel wire
stainless steel
wire
less
formula
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PCT/JP2019/023091
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French (fr)
Japanese (ja)
Inventor
祥太 山先
光司 高野
雅之 木崎
天藤　雅之
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日鉄ステンレス株式会社
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Priority to JP2020525586A priority Critical patent/JP6858931B2/en
Priority to KR1020207028798A priority patent/KR102404122B1/en
Publication of WO2019240127A1 publication Critical patent/WO2019240127A1/en

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    • 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
    • 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
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C22C38/18—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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F1/00—Springs
    • F16F1/02—Springs made of steel or other material having low internal friction; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
    • F16F1/04—Wound springs
    • F16F1/06—Wound springs with turns lying in cylindrical surfaces

Definitions

  • the present invention relates to a wire for a stainless steel wire, a stainless steel wire, a manufacturing method thereof, and a spring component.
  • Patent Document 1 aims to provide a high-strength metastable stainless steel excellent in cold workability
  • Patent Documents 2 and 3 aim to provide a high-strength stainless steel wire excellent in rigidity.
  • vertical cracks aging cracks
  • Patent Document 3 a process-induced martensite and a wire drawing process in which the temperature is controlled are combined to improve the resistance to longitudinal cracking, but such a method increases the manufacturing cost.
  • the stainless steel wire is required to have a characteristic that does not easily peel when various forces are applied, that is, a delamination resistance characteristic.
  • automotive parts such as spring parts are required to have excellent characteristics against delamination that occurs near the torsional yield point.
  • the delamination resistance characteristics are not studied at all.
  • An object of the present invention is to provide a high-strength stainless steel wire excellent in delamination resistance and a method for producing the same.
  • the present inventors have repeatedly studied focusing on the screw dislocation fraction of the austenite phase at a position of 200 ⁇ m from the surface layer of the stainless steel wire.
  • the screw dislocation fraction is measured by X-ray diffraction using CuK ⁇ rays at a position of 200 ⁇ m from the surface of the steel wire in the L cross section of the steel wire, and (111), (200), (220) (311 ) Is measured and can be obtained from the obtained data using the modified Williamson-Hall equation.
  • the present inventors have found that excellent delamination resistance characteristics can be obtained when the screw dislocation fraction is 0.9 or less. As a result of examining wire drawing conditions for obtaining a steel wire having a screw dislocation fraction of 0.9 or less, the present inventors have appropriately determined the total area reduction rate, the number of passes, and the area reduction rate in the final pass. It was found that management is particularly important.
  • the gist of the present invention is as follows.
  • the screw dislocation fraction of the austenite phase at a position of 200 ⁇ m from the surface layer of the steel wire is 0.9 or less, Stainless steel wire.
  • Md30 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
  • the element symbol in Formula (a) means content (mass%) in the steel of the said element.
  • the content of the element in the formula (a) is 0%, “0” is substituted into the corresponding symbol portion for calculation.
  • the metal structure preferably contains an austenite phase.
  • the stainless steel wire (2) preferably has a tensile strength of 1600 MPa or more and a shear strain rate for generating delamination of 3.0 ⁇ 10 ⁇ 4 / s or more.
  • a method of producing the stainless steel wire of (2) by drawing the wire of (1) above A method for producing a stainless steel wire, wherein the wire drawing is performed under conditions of a total area reduction: 40 to 90%, number of passes: 7 times or more, and area reduction of the final pass: 0.5 to 25%.
  • a high-strength stainless steel wire having excellent delamination resistance can be provided.
  • C 0.005 to 0.15% C is contained in an amount of 0.005% or more in order to obtain high strength after wire drawing. However, if C is excessively contained, vertical cracks are generated during wire drawing, and the delamination resistance is deteriorated, so the C content is 0.15% or less.
  • a preferred lower limit is 0.06% and a preferred upper limit is 0.13%.
  • Si 0.1 to 4.0% Si is contained in an amount of 0.1% or more in order to obtain high strength after wire drawing. However, if Si is excessively contained, the wire drawing workability is deteriorated and the delamination resistance is deteriorated, so the content is made 4.0% or less. Preferably it is 1.0% or less.
  • Mn 0.1 to 8.0% Mn is effective as an alternative element for expensive Ni and is an element effective for obtaining high strength after wire drawing. For this reason, Mn is contained 0.1% or more. However, if Mn is contained excessively, the delamination resistance characteristic of the steel wire is deteriorated, so the content is limited to 8.0% or less. Preferably it is 3.0% or less.
  • Ni 1.0-10.0% Ni is contained in an amount of 1.0% or more to ensure delamination resistance. Preferably, the Ni amount is 4.0% or more. However, if it is excessively contained, the Md30 value in ⁇ becomes low, and the content is made 10.0% or less in order to suppress the production of processing-induced ⁇ ′ effective for strength. Preferably, it is 9.0% or less.
  • Cr 13.0-20.0% Cr is contained in an amount of 13.0% or more in order to ensure corrosion resistance.
  • the Cr amount is 15.0% or more.
  • the content is made 20.0% or less.
  • it is 19.0% or less.
  • Mo 0.01 to 3.00% Mo is contained in an amount of 0.01% or more in order to obtain corrosion resistance and delamination resistance. However, if Mo is excessively contained, the effect is saturated and, on the contrary, the delamination resistance characteristic is lowered, so the upper limit is made 3.00% or less. Preferably it is 1.00% or less.
  • Cu more than 0.80% to 4.00% Cu has the effect of reducing the screw dislocation fraction of the steel wire and is contained in excess of 0.80%. However, when Cu is excessively contained, the hot workability is deteriorated and the strength is lowered, so the content is made 4.00% or less. Preferably, it is 3.00% or less, More preferably, it is 2.00% or less, More preferably, it is 1.50% or less.
  • N 0.005 to 0.20% N is contained in an amount of 0.005% or more in order to obtain high strength after wire drawing. However, if N is excessively contained, vertical cracks are generated during wire drawing, and the delamination resistance is deteriorated, so the N content is 0.20% or less. Preferably it is 0.10% or less. N amount is preferably 0.02 or more.
  • V 0 to 2.5% V may be contained in order to form carbonitrides to refine the crystal grain size and improve the strength and wire drawing workability of the wire and steel wire.
  • the upper limit when V is included is set to 2.5%.
  • a preferred range is 1.0% or less, and a more preferred range is 0.5% or less.
  • the V amount is preferably 0.001% or more.
  • B 0 to 0.012% B is effective for improving the grain boundary strength and improving the strength of the wire rod and the steel wire, and therefore, B may be contained. However, if B is contained excessively, the wire drawing workability and delamination resistance characteristics are reduced due to the formation of coarse boride. Therefore, the upper limit of inclusion is 0.012%. Preferably it is 0.005% or less. In order to exhibit the effect, the B content is preferably 0.001% or more.
  • Al 0 to 2.0% Al may be contained in order to promote deoxidation and improve the inclusion cleanliness level. However, if Al is contained excessively, the effect is saturated, and the strength and delamination resistance characteristics of the material itself are deteriorated. Therefore, the upper limit in the case of inclusion is 2.0%. Preferably it is 1.0% or less, More preferably, it is 0.3% or less. In order to exhibit the effect, the Al content is preferably 0.001% or more.
  • W 0 to 2.5% W is an element effective for improving the corrosion resistance, and therefore may be contained. However, when W is excessively contained, the effect is saturated, and conversely, the delamination resistance may be deteriorated. Therefore, the upper limit when it is contained is set to 2.5%. More preferably, it is 2.0% or less, More preferably, it is 1.5% or less. In order to exhibit the effect, the W content is preferably 0.05% or more. More preferably, it is 0.10% or more.
  • Ga 0 to 0.0500% Ga is an element effective for improving the corrosion resistance, so it may be contained. However, when Ga is contained excessively, hot workability is reduced. Therefore, the upper limit when it is contained is set to 0.0500%. In order to exhibit the effect, the Ga content is preferably 0.0004% or more.
  • Co 0 to 2.5% Since Co has an effect of improving the strength of the steel wire, it may be contained. However, if Co is excessively contained, the effect is saturated, and conversely, the delamination resistance characteristic of the steel wire may be deteriorated. Therefore, the upper limit when it is contained is set to 2.5%. More preferably, it is 1.0% or less, More preferably, it is 0.8% or less. In order to exhibit the effect, the Co content is preferably 0.05% or more, and more preferably 0.10% or more.
  • Sn 0 to 2.5%
  • Sn is an element effective for improving the corrosion resistance, and therefore may be contained.
  • the upper limit when it is contained is set to 2.5%. More preferably, it is 1.0% or less, More preferably, it is 0.2% or less.
  • the Sn content is preferably 0.01% or more. More preferably, it is 0.05% or more.
  • Ti, Nb, and Ta may be included in order to form carbonitrides to refine the crystal grain size and improve the strength and delamination resistance characteristics of the steel wire.
  • the upper limit in the case of making it contain shall be 1.0% for Ti, 2.5% for Nb, and 2.5% for Ta.
  • Ti is preferably 0.7% or less, and more preferably 0.5% or less.
  • Nb is preferably 1.5% or less, and more preferably 0.9% or less.
  • Ta is preferably 1.5% or less, and more preferably 0.9% or less.
  • Ti is preferably 0.03% or more, and more preferably 0.05% or more.
  • Nb is preferably 0.04% or more, and more preferably 0.08% or more.
  • Ta is preferably 0.04% or more, and more preferably 0.08% or more.
  • Ca 0 to 0.012% Mg: 0 to 0.012% Zr: 0 to 0.012% REM: 0 to 0.05%
  • Ca, Mg, Zr, and REM may be contained as necessary for deoxidation. However, coarse inclusions may be generated and the steel wire resistance to delamination and wire drawing may be reduced. Therefore, the upper limit in the case of containing is 0.012% for Ca, 0.012% for Mg, 0.012% for Zr, and 0.05% for REM.
  • Ca is preferably 0.010% or less, and more preferably 0.005% or less.
  • Mg is preferably 0.010% or less, and more preferably 0.005% or less.
  • Zr is preferably 0.010% or less, and more preferably 0.005% or less.
  • REM is preferably 0.05% or less.
  • Ca is contained by 0.0002% or more, Mg is 0.0002% or more, Zr is 0.0002% or more, and REM is 0.0002% or more.
  • Ca is preferably 0.0004% or more, and more preferably 0.001% or more.
  • Mg is preferably 0.0004% or more, and more preferably 0.001% or more.
  • Zr is preferably 0.0004% or more, and more preferably 0.001% or more.
  • REM is preferably 0.0004% or more, and more preferably 0.001% or more.
  • the chemical composition of the wire rod for stainless steel wire contains each of the above elements, and the balance consists of Fe and inevitable impurities.
  • Typical inevitable impurities include O, S, P and the like, and usually mixed in the range of 0.0001 to 0.1% as inevitable impurities in the steel manufacturing process.
  • the elements of the present invention can be contained within a range not impairing the effects. Although it does not prescribe
  • the Md30 value is an index obtained by investigating the relationship between the volume fraction of the processing-induced martensite after wire drawing and the component, and stably ensures the high strength and the hot relaxation resistance characteristics of the steel wire. Need to control in order.
  • the Md30 value is a value obtained from the following formula (a).
  • this value in the austenite phase is less than ⁇ 20, it is difficult to generate the processing-induced ⁇ ′, and the strength characteristics are inferior.
  • the Md30 value exceeds 40, the austenite phase becomes unstable, and the work-induced martensite phase generated initially by wire drawing deteriorates wire drawing workability and delamination resistance. Therefore, the Md30 value is limited to ⁇ 20 or more and 40 or less.
  • the lower limit value of the Md30 value is 0.
  • the upper limit is 20.
  • the wire according to the present embodiment has the above-described chemical composition, and the Md30 value satisfies ⁇ 20 to 40. Therefore, when a stainless steel wire is manufactured using the wire, the stainless steel wire has a volume fraction of the processing-induced martensite phase of 20 to 95 vol. %, Making it easy to obtain a high-strength stainless steel wire with excellent delamination resistance.
  • the processing induced ⁇ ′ fraction of the steel wire of the present invention is 20 vol. % Or more.
  • the volume fraction of processing-induced ⁇ ′ is 95 vol. %, The upper limit is 95 vol. In order to reduce the wire drawing workability and delamination resistance. % Or less. Preferably, 30 vol. % Or more. Moreover, Preferably, 70 vol. % Or less.
  • the phase ratio is measured using an electromagnetic measurement method, and the work-induced martensite phase is vol. %. Even if an unavoidable precipitate phase is present, 1.0 vol. %, Which is negligible compared to the work-induced martensite phase and the austenite phase. Therefore, 1.0 vol. % Is negligible, the vol% of the austenite phase is from 100% to the vol. % Minus the value.
  • the screw dislocation fraction of the austenite phase at a position of 200 ⁇ m from the surface layer of the steel wire contributes to delamination resistance characteristics. And when the screw dislocation fraction becomes excessively high, it becomes difficult to deform and the delamination resistance characteristics deteriorate, so the upper limit is made 0.9 or less. Preferably it is 0.8 or less, More preferably, it is 0.7 or less, More preferably, it is 0.6 or less. There is no need to set the lower limit of the screw dislocation fraction, but if it is too low, the strength may deteriorate, so the screw dislocation fraction is preferably 0.001 or more. A preferred lower limit is 0.01, and a more preferred lower limit is 0.05.
  • Tensile strength 1600 MPa or more
  • the tensile strength of the steel wire is less than 1600 MPa, the strength of the steel wire deteriorates, and the effects of the present invention are not exhibited. Therefore, the lower limit of the tensile strength is set to 1600 MPa or more.
  • it is 1700 MPa or more, More preferably, it is 1800 MPa or more, More preferably, it is 1900 MPa or more.
  • Shear strain rate for generating delamination 3.0 ⁇ 10 ⁇ 4 / s or more
  • the shear strain rate for generating delamination of steel wire is less than 3.0 ⁇ 10 ⁇ 4 / s, delamination resistance Since the characteristics are lowered, the effect of the present invention is not exhibited. Therefore, the lower limit is set to 3.0 ⁇ 10 ⁇ 4 / s or more. It is preferably 7.0 ⁇ 10 ⁇ 4 / s or more, more preferably 2.0 ⁇ 10 ⁇ 3 / s or more, and further preferably 3.5 ⁇ 10 ⁇ 3 / s or more.
  • the steel wire according to this embodiment has a chemical composition similar to that of the wire according to the present invention described above, and is a steel wire satisfying an Md30 value of ⁇ 20 to 40. Further, the volume fraction of processing-induced ⁇ ′ is 20 to 95 vol. Since the screw dislocation fraction of the austenite phase at a position of 200 ⁇ m from the surface layer of the steel wire is 0.9 or less, it becomes a high-strength stainless steel wire excellent in delamination resistance characteristics. In addition, the tensile strength is 1600 or more, and the steel wire has a shear strain rate of 3.0 ⁇ 10 ⁇ 4 / s or more that generates delamination.
  • the steel having the above composition is melted and cast into a slab having a predetermined diameter, and then hot wire rolling is performed on the slab. Thereafter, solution treatment and pickling are performed as necessary to obtain a wire.
  • the stainless steel wire according to the present embodiment is obtained by cold-drawing the above-described wire rod. Specifically, a steel wire or a steel wire is drawn under the following conditions to produce a stainless steel wire.
  • Total area reduction 40-90%
  • the total area reduction rate in the wire drawing is 40% or more in order to secure the amount of machining-induced ⁇ ′ and increase the strength.
  • the upper limit of the total area reduction ratio is 90%.
  • the lower limit of the total area reduction is preferably 50%, and the upper limit is preferably 80%.
  • Number of passes 7 or more Wire drawing is performed by multi-pass wire drawing with a pass number of 7 or more.
  • the number of passes means the number of times a workpiece such as a wire passes through a die. If the number of passes is too small, the screw dislocation ratio of the austenite phase at the 200 ⁇ m position is increased from the surface layer of the steel wire, and the delamination resistance characteristics are deteriorated. Preferably, it is 15 times or more, and more preferably 21 times or more.
  • Area reduction rate of the final pass 0.5-25%
  • the content is preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less.
  • the area reduction rate of the final pass is less than 0.5%, the screw dislocation fraction of the austenite phase at the 200 ⁇ m position increases from the surface layer of the steel wire, and the delamination resistance characteristics are insufficiently improved. Is 0.5% or more.
  • Tables 1 and 2 show the chemical compositions (steel types A to AR) of the steels of the examples and Md30 values in the austenite ( ⁇ ) phase.
  • the underline in Table 2 shows what is outside the scope of the present invention.
  • the steels having these chemical compositions were melted in a 100 kg vacuum melting furnace and cast into a slab of ⁇ 180 mm, assuming AOD melting, which is a cheap melting process for stainless steel.
  • the obtained slab was heated at 1100 ° C. for 200 minutes, and then hot wire rolling (reduction rate: 99.9%) was performed to ⁇ 5.5 mm, and the hot rolling was terminated at 1050 ° C.
  • an in-line heat treatment was performed at 1050 ° C. for 3 minutes as a solution treatment, water-cooled, and pickled to obtain a wire. Thereafter, the wire was drawn cold to ⁇ 4.0 mm.
  • the obtained ⁇ 4.0 mm stainless steel wire was subjected to intermediate strand annealing at 1050 ° C. for 3 minutes and subsequently subjected to cold drawing to ⁇ 2.0 mm to obtain a high-strength stainless steel wire. In this case, the total area reduction rate was 75%, the number of passes was 7, and the area reduction rate of the final pass was 10%.
  • the processing induced martensite fraction ( ⁇ ′ fraction), the screw dislocation fraction of the austenite phase at the 200 ⁇ m position from the surface layer of the steel wire, the tensile strength, The shear strain rate of delamination generation was evaluated.
  • the processing-induced ⁇ ′ fraction of the steel wire is obtained when a magnetic field of 1.0 ⁇ 10 4 Oe is applied to the “steel wire” and “material obtained by heat-treating the steel wire at 1050 ° C. ⁇ 3 minutes” with a DC magnetometer.
  • the saturation magnetization value was measured and obtained by the following formula (B).
  • a DC magnetization characteristic test apparatus manufactured by Metron Engineering Co., Ltd. was used.
  • ⁇ ′ fraction (vol.%) ⁇ ( ⁇ s ⁇ 1050 ) / ⁇ s (bcc) ⁇ ⁇ 100 (B)
  • ⁇ s is the saturation magnetization value (T) of the product
  • ⁇ 1050 is the saturation magnetization value (T) of the material obtained by heat-treating the product at 1050 ° C. ⁇ 3 minutes
  • ⁇ s (bcc) is the martensite ( ⁇ is 100%)
  • ⁇ ′) shows a saturation magnetization value (calculated value represented by the following formula (C)) when transformed. Creq in the following formula (C) is represented by the following formula (D).
  • Equation (E) D is the crystallite size (nm), ⁇ is the dislocation density (m ⁇ 2 ), b is the Burgers vector size (nm), and M is the dislocation density ⁇ and the dislocation interaction distance Re. (Nm) is a constant and C is the average contrast factor of dislocations.
  • a C C h00 (1-qH 2).
  • q e and q s are q values in the case of 100% edge dislocation and screw dislocation, respectively, and are constants determined from elastic constants.
  • Shear strain rate for delamination The shear strain rate at which delamination occurred in the steel wire was evaluated by a twist test. In the twist test, the wire diameter d of the steel wire is 2.0 mm, the distance L between chucks is 150 mm, the rotational speed R (rpm) is changed, and the shear strain speed ⁇ ′ (/ s) of the outermost layer is controlled. A torsion test was performed. At various shear strain rates, the occurrence of torque reduction after 0.3% proof stress was regarded as delamination occurrence, and the shear strain rate at which delamination occurred was used as an index of delamination resistance characteristics.
  • the processing-induced ⁇ ′ fraction was 20 to 90 vol.
  • the tensile strength was 1600 MPa or more
  • the screw dislocation fraction of the austenite phase at a position of 200 ⁇ m from the surface layer of the steel wire was 0.9 or less.
  • the shear strain rate of delamination generation in Invention Examples 1 to 33 was 3.0 ⁇ 10 ⁇ 4 / s or more.
  • Comparative Example No. In No. 41 since the corrosion resistance was poor, the tensile strength and delamination were not evaluated.
  • the steel wires of the examples of the present invention shown in 45 to 53 all have a processing-induced ⁇ ′ fraction of 20 to 90 vol. %,
  • the austenite phase screw dislocation fraction at a position of 200 ⁇ m from the surface layer of the steel wire is 0.9 or less, the tensile strength is 1600 MPa or more, and the shear strain rate at which delamination occurs is 3.0 ⁇ 10 ⁇ 4. / S or more.
  • the steel wires of Comparative Examples 54 to 58 in which the wire drawing was not performed under appropriate conditions the performance of either tensile strength or delamination resistance was deteriorated.
  • a high-strength stainless steel wire having excellent delamination resistance characteristics can be provided, which is extremely useful industrially.
  • a spring component means the spring for motor vehicles, the spring for industrial machines, the spring for household appliances, etc.

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  • Heat Treatment Of Steel (AREA)

Abstract

This wire rod for stainless steel wire is characterized by containing: 0.005-0.15% of C; 0.1-4.0% of Si; 0.1-8.0% of Mn; 1.0-10.0% of Ni; 13.0-20.0% of Cr; 0.01-3.00% of Mo; greater than 0.80% to 4.00% of Cu; 0.005-0.20% of N; V, etc. as necessary; and the remainder comprising Fe and unavoidable impurities The wire rod is also characterized in thatMd30 represented by formula (a) is -20 to 40. A high-strength stainless steel wire having excellent anti-delamination property is obtained from this wire rod. Formula (a): Md30 = 551-462(C+N)-9.2Si-8.1Mn-29(Ni+Cu)-13.7Cr-18.5Mo The symbols of the elements in formula (a) each denote the content (mass%) of the corresponding element in the steel. If the content of any element in formula (a) is 0%, calculation is carried out with "0" substituted into the place of the corresponding symbol.

Description

ステンレス鋼線用の線材、ステンレス鋼線およびその製造方法、ならびに、ばね部品Stainless steel wire, stainless steel wire and method for producing the same, and spring component
　本発明は、ステンレス鋼線用の線材、ステンレス鋼線およびその製造方法、ならびに、ばね部品に関する。 The present invention relates to a wire for a stainless steel wire, a stainless steel wire, a manufacturing method thereof, and a spring component.
　従来、コイルばねに代表されるような、高強度ステンレス製品は、ＳＵＳ３０４、ＳＵＳ３１６を代表とするオーステナイト系ステンレス鋼線材、鋼線を素材として加工・成型され製造されてきた。しかしながら、上記のようなオーステナイト系ステンレス鋼線材から加工、製造されたステンレス製品の強度特性や耐デラミネーション特性は精密部品に十分対応できず、用途の制限を受ける欠点があった。 Conventionally, high-strength stainless steel products represented by coil springs have been processed and molded from austenitic stainless steel wires and steel wires represented by SUS304 and SUS316. However, the strength characteristics and delamination resistance characteristics of the stainless steel products processed and manufactured from the austenitic stainless steel wire as described above cannot sufficiently cope with precision parts, and have a drawback of being restricted in use.
　上記課題に対して、加工誘起マルテンサイト（以下本明細書において加工誘起α’という場合がある）による強化を利用する技術が検討されている（例えば、特許文献１、２、および３）。 In order to solve the above-mentioned problems, techniques using reinforcement by processing-induced martensite (hereinafter sometimes referred to as processing-induced α ′ in the present specification) have been studied (for example, Patent Documents 1, 2, and 3).
特開２００１－２６２２８１号公報JP 2001-262281 A 特開２００５－２９０５３８号公報JP 2005-290538 A 特開２００５－２９８９３２号公報JP 2005-298932 A
　特許文献１の発明は、冷間加工性に優れた高強度準安定ステンレス鋼の提供を、特許文献２および３の発明は、剛性率に優れた高強度ステンレス鋼線の提供を目的としており、これらの発明では、冷間伸線加工時の縦割れ（時効割れ）について検討されている。なお、特許文献３では、加工誘起マルテンサイトと温度を制御した伸線加工を組み合わせて耐伸線縦割れ性の向上を図っているが、そのような方法は製造コストを上昇させる。 The invention of Patent Document 1 aims to provide a high-strength metastable stainless steel excellent in cold workability, and the inventions of Patent Documents 2 and 3 aim to provide a high-strength stainless steel wire excellent in rigidity. In these inventions, vertical cracks (aging cracks) during cold wire drawing are studied. In Patent Document 3, a process-induced martensite and a wire drawing process in which the temperature is controlled are combined to improve the resistance to longitudinal cracking, but such a method increases the manufacturing cost.
　ここで、ステンレス鋼線には、種々の力が付与されたときに剥離しにくい特性、すなわち、耐デラミネーション特性が求められる。特に、ばね部品などの自動車用部品においては、ねじり降伏点近傍で生じるデラミネーションに対する特性に優れていることが求められる。しかし、上記の特許文献１～３の発明では、耐デラミネーション特性について一切検討されていない。 Here, the stainless steel wire is required to have a characteristic that does not easily peel when various forces are applied, that is, a delamination resistance characteristic. In particular, automotive parts such as spring parts are required to have excellent characteristics against delamination that occurs near the torsional yield point. However, in the inventions of Patent Documents 1 to 3 described above, the delamination resistance characteristics are not studied at all.
　本発明の課題は、耐デラミネーション特性に優れる高強度ステンレス鋼線およびその製造方法を提供することにある。 An object of the present invention is to provide a high-strength stainless steel wire excellent in delamination resistance and a method for producing the same.
　本発明者らは、上記の課題を解決するために、ステンレス鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率に着目して検討を重ねた。らせん転位分率とは、鋼線のＬ断面において、鋼線の表層から２００μｍ位置において、Ｘ線回折にてＣｕＫα線を用いて測定を行い、（１１１）、（２００）、（２２０）（３１１）の半価幅を測定し、得られたデータからｍｏｄｉｆｉｅｄ　Ｗｉｌｌｉａｍｓｏｎ－Ｈａｌｌ式を用いて、求めることができる。 In order to solve the above-mentioned problems, the present inventors have repeatedly studied focusing on the screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the stainless steel wire. The screw dislocation fraction is measured by X-ray diffraction using CuKα rays at a position of 200 μm from the surface of the steel wire in the L cross section of the steel wire, and (111), (200), (220) (311 ) Is measured and can be obtained from the obtained data using the modified Williamson-Hall equation.
　そして、本発明者らは、らせん転位分率が０．９以下である場合に、優れた耐デラミネーション特性が得られることを見出した。本発明者らは、らせん転位分率が０．９以下である鋼線を得るための伸線加工条件についての検討をした結果、総減面率、パス回数および最終パスにおける減面率を適切に管理することが特に重要であることを見出した。
　本発明の要旨は下記のとおりである。 The present inventors have found that excellent delamination resistance characteristics can be obtained when the screw dislocation fraction is 0.9 or less. As a result of examining wire drawing conditions for obtaining a steel wire having a screw dislocation fraction of 0.9 or less, the present inventors have appropriately determined the total area reduction rate, the number of passes, and the area reduction rate in the final pass. It was found that management is particularly important.
The gist of the present invention is as follows.
（１）　質量％で、
Ｃ　：０．００５～０．１５％、
Ｓｉ：０．１～４．０％、
Ｍｎ：０．１～８．０％、
Ｎｉ：１．０～１０．０％、
Ｃｒ：１３．０～２０．０％、
Ｍｏ：０．０１～３．００％、
Ｃｕ：０．８０％超～４．００％、
Ｎ　：０．００５～０．２０％、
Ｖ　：０～２．５％、
Ｂ　：０～０．０１２％、
Ａｌ：０～２．０％、
Ｗ　：０～２．５％、
Ｇａ：０～０．０５００％、
Ｃｏ：０～２．５％、
Ｓｎ：０～２．５％、
Ｔｉ：０～１．０％、
Ｎｂ：０～２．５％、
Ｔａ：０～２．５％、
Ｃａ：０～０．０１２％、
Ｍｇ：０～０．０１２％、
Ｚｒ：０～０．０１２％、
ＲＥＭ：０～０．０５％、
残部がＦｅおよび不可避的不純物からなり、
　下記式（ａ）で示されるＭｄ３０が－２０～４０である、
ステンレス鋼線用の線材。
　Ｍｄ３０＝５５１－４６２（Ｃ＋Ｎ）－９．２Ｓｉ－８．１Ｍｎ－２９（Ｎｉ＋Ｃｕ）－１３．７Ｃｒ－１８．５Ｍｏ　　…　（ａ）
　但し、式（ａ）中の元素記号は、当該元素の鋼中における含有量（質量％）を意味する。また、式（ａ）中の元素の含有量が０％である場合は、該当記号箇所には「０」を代入して算出する。 (1) In mass%,
C: 0.005 to 0.15%,
Si: 0.1 to 4.0%,
Mn: 0.1 to 8.0%,
Ni: 1.0-10.0%,
Cr: 13.0-20.0%,
Mo: 0.01 to 3.00%,
Cu: more than 0.80% to 4.00%,
N: 0.005 to 0.20%,
V: 0 to 2.5%
B: 0 to 0.012%,
Al: 0 to 2.0%,
W: 0 to 2.5%
Ga: 0 to 0.0500%,
Co: 0 to 2.5%,
Sn: 0 to 2.5%,
Ti: 0 to 1.0%,
Nb: 0 to 2.5%,
Ta: 0 to 2.5%,
Ca: 0 to 0.012%,
Mg: 0 to 0.012%,
Zr: 0 to 0.012%,
REM: 0 to 0.05%,
The balance consists of Fe and inevitable impurities,
Md30 represented by the following formula (a) is -20 to 40,
Wire for stainless steel wire.
Md30 = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
However, the element symbol in Formula (a) means content (mass%) in the steel of the said element. In addition, when the content of the element in the formula (a) is 0%, “0” is substituted into the corresponding symbol portion for calculation.
（２）　質量％で、
Ｃ　：０．００５～０．１５％、
Ｓｉ：０．１～４．０％、
Ｍｎ：０．１～８．０％、
Ｎｉ：１．０～１０．０％、
Ｃｒ：１３．０～２０．０％、
Ｍｏ：０．０１～３．００％、
Ｃｕ：０．８０％超～４．００％、
Ｎ　：０．００５～０．２０％、
Ｖ　：０～２．５％、
Ｂ　：０～０．０１２％、
Ａｌ：０～２．０％、
Ｗ　：０～２．５％、
Ｇａ：０～０．０５００％、
Ｃｏ：０～２．５％、
Ｓｎ：０～２．５％、
Ｔｉ：０～１．０％、
Ｎｂ：０～２．５％、
Ｔａ：０～２．５％、
Ｃａ：０～０．０１２％、
Ｍｇ：０．０１２％、
Ｚｒ：０～０．０１２％、
ＲＥＭ：０～０．０５％、
残部がＦｅおよび不可避的不純物からなり、
　下記式（ａ）で示されるＭｄ３０が－２０～４０であり、
　加工誘起マルテンサイト相が２０～９５ｖｏｌ．％である金属組織を有し、
　鋼線の表層から２００μｍの位置におけるオーステナイト相のらせん転位分率が０．９以下である、
ステンレス鋼線。
　Ｍｄ３０＝５５１－４６２（Ｃ＋Ｎ）－９．２Ｓｉ－８．１Ｍｎ－２９（Ｎｉ＋Ｃｕ）－１３．７Ｃｒ－１８．５Ｍｏ　　…　（ａ）
　但し、式（ａ）中の元素記号は、当該元素の鋼中における含有量（質量％）を意味する。また、式（ａ）中の元素の含有量が０％である場合は、該当記号箇所には「０」を代入して算出する。 (2) By mass%
C: 0.005 to 0.15%,
Si: 0.1 to 4.0%,
Mn: 0.1 to 8.0%,
Ni: 1.0-10.0%,
Cr: 13.0-20.0%,
Mo: 0.01 to 3.00%,
Cu: more than 0.80% to 4.00%,
N: 0.005 to 0.20%,
V: 0 to 2.5%
B: 0 to 0.012%,
Al: 0 to 2.0%,
W: 0 to 2.5%
Ga: 0 to 0.0500%,
Co: 0 to 2.5%,
Sn: 0 to 2.5%,
Ti: 0 to 1.0%,
Nb: 0 to 2.5%,
Ta: 0 to 2.5%,
Ca: 0 to 0.012%,
Mg: 0.012%,
Zr: 0 to 0.012%,
REM: 0 to 0.05%,
The balance consists of Fe and inevitable impurities,
Md30 represented by the following formula (a) is −20 to 40,
The processing-induced martensite phase is 20 to 95 vol. % Having a metallographic structure,
The screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire is 0.9 or less,
Stainless steel wire.
Md30 = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
However, the element symbol in Formula (a) means content (mass%) in the steel of the said element. In addition, when the content of the element in the formula (a) is 0%, “0” is substituted into the corresponding symbol portion for calculation.
　上記（２）のステンレス鋼線は、前記金属組織が、オーステナイト相を含むのが好ましい。また、上記（２）のステンレス鋼線は、引張強さが１６００ＭＰａ以上、デラミネーションを発生するせん断ひずみ速度が３．０×１０－４／ｓ以上であることが好ましい。 In the stainless steel wire (2), the metal structure preferably contains an austenite phase. The stainless steel wire (2) preferably has a tensile strength of 1600 MPa or more and a shear strain rate for generating delamination of 3.0 × 10 −4 / s or more.
（３）上記（１）の線材を伸線加工して上記（２）のステンレス鋼線を製造する方法であって、
　前記伸線加工を、総減面率：４０～９０％、パス回数：７回以上、最終パスの減面率：０．５～２５％の条件で行う、ステンレス鋼線の製造方法。 (3) A method of producing the stainless steel wire of (2) by drawing the wire of (1) above,
A method for producing a stainless steel wire, wherein the wire drawing is performed under conditions of a total area reduction: 40 to 90%, number of passes: 7 times or more, and area reduction of the final pass: 0.5 to 25%.
（４）上記（２）のステンレス鋼線を用いたばね部品。 (4) A spring component using the stainless steel wire of (2) above.
　本発明によれば、耐デラミネーション特性に優れる高強度ステンレス鋼線を提供できる。 According to the present invention, a high-strength stainless steel wire having excellent delamination resistance can be provided.
　１．ステンレス鋼線用線材
　先ず、ステンレス鋼線用の線材の化学組成について説明する。なお、以下の説明における（％）は特に断りがない限り、質量（％）である。 1. First, the chemical composition of the wire for stainless steel wire will be described. In the following description, (%) is mass (%) unless otherwise specified.
　Ｃ　：０．００５～０．１５％
　Ｃは、伸線加工後に高強度を得るために、０．００５％以上含有させる。しかしながら、Ｃを過剰に含有させると、伸線加工時に縦割れが発生し、また、耐デラミネーション特性を低下させるため、Ｃ含有量は０．１５％以下とする。好ましい下限は０．０６％であり、好ましい上限は０．１３％である。 C: 0.005 to 0.15%
C is contained in an amount of 0.005% or more in order to obtain high strength after wire drawing. However, if C is excessively contained, vertical cracks are generated during wire drawing, and the delamination resistance is deteriorated, so the C content is 0.15% or less. A preferred lower limit is 0.06% and a preferred upper limit is 0.13%.
　Ｓｉ：０．１～４．０％
　Ｓｉは、伸線加工後に高強度を得るために、０．１％以上含有させる。しかしながら、Ｓｉを過剰に含有させると、伸線加工性が悪くなり、また、耐デラミネーション特性を低下させるため、その含有量を４．０％以下にする。好ましくは１．０％以下である。 Si: 0.1 to 4.0%
Si is contained in an amount of 0.1% or more in order to obtain high strength after wire drawing. However, if Si is excessively contained, the wire drawing workability is deteriorated and the delamination resistance is deteriorated, so the content is made 4.0% or less. Preferably it is 1.0% or less.
　Ｍｎ：０．１～８．０％
　Ｍｎは、高価なＮｉの代替元素として有効であり、伸線加工後に高強度を得るのに有効な元素である。このため、Ｍｎは０．１％以上含有させる。しかしながら、Ｍｎを過剰に含有させると、鋼線の耐デラミネーション特性を劣化させるため、その含有量を８．０％以下に限定する。好ましくは３．０％以下とする。 Mn: 0.1 to 8.0%
Mn is effective as an alternative element for expensive Ni and is an element effective for obtaining high strength after wire drawing. For this reason, Mn is contained 0.1% or more. However, if Mn is contained excessively, the delamination resistance characteristic of the steel wire is deteriorated, so the content is limited to 8.0% or less. Preferably it is 3.0% or less.
　Ｎｉ：１．０～１０．０％
　Ｎｉは、耐デラミネーション特性を確保するため、１．０％以上含有させる。好ましくは、Ｎｉ量を４．０％以上とする。しかしながら、過剰に含有させると、γ中のＭｄ３０値が低くなり、強度に有効な加工誘起α’の生成を抑制するため、その含有量を１０．０％以下にする。好ましくは、９．０％以下である。 Ni: 1.0-10.0%
Ni is contained in an amount of 1.0% or more to ensure delamination resistance. Preferably, the Ni amount is 4.0% or more. However, if it is excessively contained, the Md30 value in γ becomes low, and the content is made 10.0% or less in order to suppress the production of processing-induced α ′ effective for strength. Preferably, it is 9.0% or less.
　Ｃｒ：１３．０～２０．０％
　Ｃｒは、耐食性を確保するため、１３．０％以上含有させる。好ましくはＣｒ量を１５．０％以上とする。しかしながら、Ｃｒを過剰に含有させると、鋼線の耐デラミネーション特性を劣化させるため、その含有量を２０．０％以下にする。好ましくは、１９．０％以下である。 Cr: 13.0-20.0%
Cr is contained in an amount of 13.0% or more in order to ensure corrosion resistance. Preferably, the Cr amount is 15.0% or more. However, when Cr is excessively contained, the delamination resistance characteristic of the steel wire is deteriorated, so the content is made 20.0% or less. Preferably, it is 19.0% or less.
　Ｍｏ：０．０１～３．００％
　Ｍｏは、耐食性と耐デラミネーション特性を得るために、０．０１％以上含有させる。しかしながら、Ｍｏを過剰に含有させると、その効果は飽和し、逆に耐デラミネーション特性が低下するため、上限を３．００％以下にする。好ましくは１．００％以下である。 Mo: 0.01 to 3.00%
Mo is contained in an amount of 0.01% or more in order to obtain corrosion resistance and delamination resistance. However, if Mo is excessively contained, the effect is saturated and, on the contrary, the delamination resistance characteristic is lowered, so the upper limit is made 3.00% or less. Preferably it is 1.00% or less.
　Ｃｕ：０．８０％超～４．００％
　Ｃｕは、鋼線のらせん転位分率を低下させる効果があり、０．８０％を超えて含有させる。しかしながら、Ｃｕを過剰に含有させると、熱間加工性が劣化することに加え、強度が低下するため、その含有量を４．００％以下とする。好ましくは、３．００％以下であり、更に好ましくは２．００％以下、更に好ましくは１．５０％以下である。 Cu: more than 0.80% to 4.00%
Cu has the effect of reducing the screw dislocation fraction of the steel wire and is contained in excess of 0.80%. However, when Cu is excessively contained, the hot workability is deteriorated and the strength is lowered, so the content is made 4.00% or less. Preferably, it is 3.00% or less, More preferably, it is 2.00% or less, More preferably, it is 1.50% or less.
　Ｎ　：０．００５～０．２０％
　Ｎは、伸線加工後に高強度を得るために、０．００５％以上含有させる。しかしながら、Ｎを過剰に含有させると、伸線加工時に縦割れが発生し、また耐デラミネーション特性を低下させるため、Ｎ量を０．２０％以下とする。好ましくは０．１０％以下である。Ｎ量は０．０２以上が好ましい。 N: 0.005 to 0.20%
N is contained in an amount of 0.005% or more in order to obtain high strength after wire drawing. However, if N is excessively contained, vertical cracks are generated during wire drawing, and the delamination resistance is deteriorated, so the N content is 0.20% or less. Preferably it is 0.10% or less. N amount is preferably 0.02 or more.
　Ｖ　：０～２．５％
　Ｖは、炭窒化物を形成して結晶粒径を微細にして、線材、鋼線の強度と伸線加工性を改善するため、含有させてもよい。しかしながら、Ｖを過剰に含有させると、粗大介在物が生成し、伸線加工性と耐デラミネーション特性が低下するため、含有させる場合の上限を２．５％とする。好ましい範囲は１．０％以下であり、更に好ましい範囲は０．５％以下である。前記効果を発現させるためには、Ｖ量を０．００１％以上とするのが好ましい。 V: 0 to 2.5%
V may be contained in order to form carbonitrides to refine the crystal grain size and improve the strength and wire drawing workability of the wire and steel wire. However, when V is excessively contained, coarse inclusions are generated, and the wire drawing workability and delamination resistance characteristics are lowered. Therefore, the upper limit when V is included is set to 2.5%. A preferred range is 1.0% or less, and a more preferred range is 0.5% or less. In order to exhibit the effect, the V amount is preferably 0.001% or more.
　Ｂ　：０～０．０１２％
　Ｂは、粒界強度を向上させて、線材、鋼線の強度を向上させるのに有効であるため、含有させてもよい。しかしながら、Ｂを過剰に含有させると、粗大なボライド生成により、逆に伸線加工性と耐デラミネーション特性が低下するため、含有させる場合の上限を０．０１２％とする。好ましくは０．００５％以下である。前記効果を発現させるためには、Ｂ量を０．００１％以上とするのが好ましい。 B: 0 to 0.012%
B is effective for improving the grain boundary strength and improving the strength of the wire rod and the steel wire, and therefore, B may be contained. However, if B is contained excessively, the wire drawing workability and delamination resistance characteristics are reduced due to the formation of coarse boride. Therefore, the upper limit of inclusion is 0.012%. Preferably it is 0.005% or less. In order to exhibit the effect, the B content is preferably 0.001% or more.
　Ａｌ：０～２．０％
　Ａｌは、脱酸を促進して介在物清浄度レベルを向上させるため、含有させてもよい。しかしながら、Ａｌを過剰に含有させると、その効果は飽和し、材料自体の強度と耐デラミネーション特性が劣化するため、含有させる場合の上限を２．０％とする。好ましくは１．０％以下であり、更に好ましくは０．３％以下である。前記効果を発現させるには、Ａｌ量を０．００１％以上とするのが好ましい。 Al: 0 to 2.0%
Al may be contained in order to promote deoxidation and improve the inclusion cleanliness level. However, if Al is contained excessively, the effect is saturated, and the strength and delamination resistance characteristics of the material itself are deteriorated. Therefore, the upper limit in the case of inclusion is 2.0%. Preferably it is 1.0% or less, More preferably, it is 0.3% or less. In order to exhibit the effect, the Al content is preferably 0.001% or more.
　Ｗ　：０～２．５％
　Ｗは、耐食性を向上させるのに有効な元素であるため、含有させてもよい。しかしながら、Ｗを過剰に含有させると、その効果は飽和し、逆に耐デラミネーション特性が劣化するおそれがある。そのため、含有させる場合の上限を２．５％とする。より好ましくは、２．０％以下であり、更に好ましくは１．５％以下である。前記効果を発現させるには、Ｗ量を０．０５％以上とすることが好ましい。より好ましくは、０．１０％以上である。 W: 0 to 2.5%
W is an element effective for improving the corrosion resistance, and therefore may be contained. However, when W is excessively contained, the effect is saturated, and conversely, the delamination resistance may be deteriorated. Therefore, the upper limit when it is contained is set to 2.5%. More preferably, it is 2.0% or less, More preferably, it is 1.5% or less. In order to exhibit the effect, the W content is preferably 0.05% or more. More preferably, it is 0.10% or more.
　Ｇａ：０～０．０５００％
　Ｇａは、耐食性を向上させるのに有効な元素であるため、含有させてもよい。しかしながら、Ｇａを過剰に含有させると、熱間加工性を低下させる。そのため、含有させる場合の上限を、０．０５００％とする。前記効果を発現させるには、Ｇａ量を０．０００４％以上とすることが好ましい。 Ga: 0 to 0.0500%
Ga is an element effective for improving the corrosion resistance, so it may be contained. However, when Ga is contained excessively, hot workability is reduced. Therefore, the upper limit when it is contained is set to 0.0500%. In order to exhibit the effect, the Ga content is preferably 0.0004% or more.
　Ｃｏ：０～２．５％
　Ｃｏは、鋼線の強度を向上させる効果を有するため、含有させてもよい。しかしながら、Ｃｏを過剰に含有させると、その効果は飽和し、逆に鋼線の耐デラミネーション特性が劣化するおそれがある。そのため、含有させる場合の上限を２．５％とする。より好ましくは、１．０％以下であり、更に好ましくは０．８％以下である。前記効果を発現させるには、Ｃｏ量を０．０５％以上とすることが好ましく、０．１０％以上含有させることがより好ましい。 Co: 0 to 2.5%
Since Co has an effect of improving the strength of the steel wire, it may be contained. However, if Co is excessively contained, the effect is saturated, and conversely, the delamination resistance characteristic of the steel wire may be deteriorated. Therefore, the upper limit when it is contained is set to 2.5%. More preferably, it is 1.0% or less, More preferably, it is 0.8% or less. In order to exhibit the effect, the Co content is preferably 0.05% or more, and more preferably 0.10% or more.
　Ｓｎ：０～２．５％
　Ｓｎは、耐食性を向上させるのに有効な元素であるため、含有させてもよい。しかしながら、Ｓｎを過剰に含有させると、その効果は飽和し、逆に耐デラミネーション特性が劣化するおそれがある。そのため、含有させる場合の上限を２．５％とする。より好ましくは、１．０％以下であり、更に好ましくは０．２％以下である。前記効果を発現させるには、Ｓｎ量を０．０１％以上とすることが好ましい。より好ましくは、０．０５％以上である。 Sn: 0 to 2.5%
Sn is an element effective for improving the corrosion resistance, and therefore may be contained. However, when Sn is excessively contained, the effect is saturated, and conversely, the delamination resistance property may be deteriorated. Therefore, the upper limit when it is contained is set to 2.5%. More preferably, it is 1.0% or less, More preferably, it is 0.2% or less. In order to exhibit the effect, the Sn content is preferably 0.01% or more. More preferably, it is 0.05% or more.
　Ｔｉ：０～１．０％
　Ｎｂ：０～２．５％
　Ｔａ：０～２．５％
　Ｔｉ、Ｎｂ、Ｔａは、炭窒化物を形成して結晶粒径を微細にして、鋼線の強度と耐デラミネーション特性を改善するため、含有させてもよい。しかしながら、これら各元素を過剰に含有させると、粗大介在物が生成し、鋼線の耐デラミネーション特性が低下するおそれがある。そのため、含有させる場合の上限を、Ｔｉは１．０％、Ｎｂは２．５％、Ｔａは２．５％とする。Ｔｉは、０．７％以下とするのが好ましく、０．５％以下とするのがより好ましい。Ｎｂは、１．５％以下とするのが好ましく、０．９％以下とするのがより好ましい。Ｔａは、１．５％以下とするのが好ましく、０．９％以下とするのがより好ましい。前記効果を発現させるには、Ｔｉは０．０１％以上、Ｎｂは０．０１％以上、Ｔａは０．０１％以上含有させるのが好ましい。Ｔｉは、０．０３％以上とするのが好ましく、０．０５％以上とするのがより好ましい。Ｎｂは、０．０４％以上とするのが好ましく、０．０８％以上とするのがより好ましい。Ｔａは、０．０４％以上とするのが好ましく、０．０８％以上とするのがより好ましい。 Ti: 0 to 1.0%
Nb: 0 to 2.5%
Ta: 0 to 2.5%
Ti, Nb, and Ta may be included in order to form carbonitrides to refine the crystal grain size and improve the strength and delamination resistance characteristics of the steel wire. However, when these elements are contained excessively, coarse inclusions are generated, and the delamination resistance characteristics of the steel wire may be deteriorated. Therefore, the upper limit in the case of making it contain shall be 1.0% for Ti, 2.5% for Nb, and 2.5% for Ta. Ti is preferably 0.7% or less, and more preferably 0.5% or less. Nb is preferably 1.5% or less, and more preferably 0.9% or less. Ta is preferably 1.5% or less, and more preferably 0.9% or less. In order to exhibit the effect, it is preferable to contain Ti 0.01% or more, Nb 0.01% or more, and Ta 0.01% or more. Ti is preferably 0.03% or more, and more preferably 0.05% or more. Nb is preferably 0.04% or more, and more preferably 0.08% or more. Ta is preferably 0.04% or more, and more preferably 0.08% or more.
　Ｃａ：０～０．０１２％
　Ｍｇ：０～０．０１２％
　Ｚｒ：０～０．０１２％
　ＲＥＭ：０～０．０５％
　Ｃａ、Ｍｇ、Ｚｒ、ＲＥＭは、脱酸のため、必要に応じて、含有させてもよい。しかしながら、粗大介在物が生成して鋼線の耐デラミネーション特性と伸線加工性とが低下するおそれがある。そのため、含有させる場合の上限は、Ｃａは０．０１２％、Ｍｇは０．０１２％、Ｚｒは０．０１２％、ＲＥＭは０．０５％とする。Ｃａは、０．０１０％以下とするのが好ましく、０．００５％以下とするのがより好ましい。Ｍｇは、０．０１０％以下とするのが好ましく、０．００５％以下とするのがより好ましい。Ｚｒは、０．０１０％以下とするのが好ましく、０．００５％以下とするのがより好ましい。ＲＥＭは、０．０５％以下とするのが好ましい。前記効果を発現させるには、Ｃａは０．０００２％以上、Ｍｇは０．０００２％以上、Ｚｒは０．０００２％以上、ＲＥＭは０．０００２％以上含有させるのが好ましい。Ｃａは、０．０００４％以上とするのが好ましく、０．００１％以上とするのがより好ましい。Ｍｇは、０．０００４％以上とするのが好ましく、０．００１％以上とするのがより好ましい。Ｚｒは、０．０００４％以上とするのが好ましく、０．００１％以上とするのがより好ましい。ＲＥＭは、０．０００４％以上とするのが好ましく、０．００１％以上とするのがより好ましい。 Ca: 0 to 0.012%
Mg: 0 to 0.012%
Zr: 0 to 0.012%
REM: 0 to 0.05%
Ca, Mg, Zr, and REM may be contained as necessary for deoxidation. However, coarse inclusions may be generated and the steel wire resistance to delamination and wire drawing may be reduced. Therefore, the upper limit in the case of containing is 0.012% for Ca, 0.012% for Mg, 0.012% for Zr, and 0.05% for REM. Ca is preferably 0.010% or less, and more preferably 0.005% or less. Mg is preferably 0.010% or less, and more preferably 0.005% or less. Zr is preferably 0.010% or less, and more preferably 0.005% or less. REM is preferably 0.05% or less. In order to exhibit the above effects, it is preferable that Ca is contained by 0.0002% or more, Mg is 0.0002% or more, Zr is 0.0002% or more, and REM is 0.0002% or more. Ca is preferably 0.0004% or more, and more preferably 0.001% or more. Mg is preferably 0.0004% or more, and more preferably 0.001% or more. Zr is preferably 0.0004% or more, and more preferably 0.001% or more. REM is preferably 0.0004% or more, and more preferably 0.001% or more.
　ステンレス鋼線用の線材の化学組成は、上記の各元素を含有し、残部は、Ｆｅ及び不可避的不純物からなる。代表的な不可避的不純物としては、Ｏ、Ｓ、Ｐなどが挙げられ、通常、鉄鋼の製造プロセスで不可避的不純物として０．０００１～０．１％の範囲で混入する。 The chemical composition of the wire rod for stainless steel wire contains each of the above elements, and the balance consists of Fe and inevitable impurities. Typical inevitable impurities include O, S, P and the like, and usually mixed in the range of 0.0001 to 0.1% as inevitable impurities in the steel manufacturing process.
　以上説明した各元素の他にも、本発明の効果を損なわない範囲で含有させることが出来る。その他の成分について本発明では特に規定するものではないが、一般的な不純物元素でありＰ、Ｓ、Ｚｎ、Ｂｉ、Ｐｂ、Ｓｅ、Ｓｂ、Ｈ等は可能な限り低減することが好ましい。これらの元素は、本発明の課題を解決する限度において、その含有割合が制御され、必要に応じて、Ｐ≦４００ｐｐｍ、Ｓ≦１００ｐｐｍ、Ｚｎ≦１００ｐｐｍ、Ｂｉ≦１００ｐｐｍ、Ｐｂ≦１００ｐｐｍ、Ｓｅ≦１００ｐｐｍ、Ｓｂ≦５００ｐｐｍ、Ｈ≦１００ｐｐｍの１種以上を含有する。 In addition to the elements described above, the elements of the present invention can be contained within a range not impairing the effects. Although it does not prescribe | regulate especially about another component in this invention, it is preferable to reduce as much as possible P, S, Zn, Bi, Pb, Se, Sb, H etc. which are general impurity elements. The content of these elements is controlled within the limits to solve the problems of the present invention, and P ≦ 400 ppm, S ≦ 100 ppm, Zn ≦ 100 ppm, Bi ≦ 100 ppm, Pb ≦ 100 ppm, Se ≦ 100 ppm as necessary. , Sb ≦ 500 ppm, H ≦ 100 ppm.
　Ｍｄ３０値：－２０～４０
　Ｍｄ３０値は、伸線加工後の加工誘起マルテンサイトの体積分率と成分の関係をそれぞれ調査して得られた指標であり、高強度と鋼線の耐温間リラクセーション特性を安定的に確保するために制御する必要がある。 Md30 value: -20 to 40
The Md30 value is an index obtained by investigating the relationship between the volume fraction of the processing-induced martensite after wire drawing and the component, and stably ensures the high strength and the hot relaxation resistance characteristics of the steel wire. Need to control in order.
　Ｍｄ３０値は、下記式（ａ）より求められる値であり、オーステナイト相中のこの値が－２０を下回ると、加工誘起α’を生成し難くなり、強度特性を劣位にする。一方、Ｍｄ３０値が４０を超える場合、オーステナイト相が不安定となり、伸線加工で初期に生成した加工誘起マルテンサイト相が伸線加工性と耐デラミネーション特性を低下させる。そのため、Ｍｄ３０値を－２０以上、４０以下に限定する。好ましくは、Ｍｄ３０値の下限値は０とする。上限値は２０とする。
　Ｍｄ３０＝５５１－４６２（Ｃ＋Ｎ）－９．２Ｓｉ－８．１Ｍｎ－２９（Ｎｉ＋Ｃｕ）－１３．７Ｃｒ－１８．５Ｍｏ　　…　（ａ）
　但し、式（ａ）中の元素記号は、当該元素の鋼中における含有量（質量％）を意味する。また、式（ａ）中の元素の含有量が０％である場合は、該当記号箇所には「０」を代入して算出する。 The Md30 value is a value obtained from the following formula (a). When this value in the austenite phase is less than −20, it is difficult to generate the processing-induced α ′, and the strength characteristics are inferior. On the other hand, when the Md30 value exceeds 40, the austenite phase becomes unstable, and the work-induced martensite phase generated initially by wire drawing deteriorates wire drawing workability and delamination resistance. Therefore, the Md30 value is limited to −20 or more and 40 or less. Preferably, the lower limit value of the Md30 value is 0. The upper limit is 20.
Md30 = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
However, the element symbol in Formula (a) means content (mass%) in the steel of the said element. In addition, when the content of the element in the formula (a) is 0%, “0” is substituted into the corresponding symbol portion for calculation.
　本実施形態に係る線材は、上述の化学組成を有し、Ｍｄ３０値が－２０～４０を満足するものとなる。そのため、当該線材を用いてステンレス鋼線を製造した場合に、当該ステンレス鋼線は、加工誘起マルテンサイト相の体積分率が２０～９５ｖｏｌ．％となり、耐デラミネーション特性に優れた高強度ステンレス鋼線を得やすくなる。 The wire according to the present embodiment has the above-described chemical composition, and the Md30 value satisfies −20 to 40. Therefore, when a stainless steel wire is manufactured using the wire, the stainless steel wire has a volume fraction of the processing-induced martensite phase of 20 to 95 vol. %, Making it easy to obtain a high-strength stainless steel wire with excellent delamination resistance.
　２．ステンレス鋼線
　本実施形態に係るステンレス鋼線の化学組成およびＭｄ３０値は、線材の化学組成およびＭｄ３０値と同様であるので、説明を割愛する。 2. Stainless Steel Wire Since the chemical composition and Md30 value of the stainless steel wire according to the present embodiment are the same as the chemical composition and Md30 value of the wire, the description thereof is omitted.
　加工誘起マルテンサイト相：２０～９５ｖｏｌ．％
　鋼線の加工誘起α’の体積分率について、２０ｖｏｌ．％未満では、強度特性を得られない。そのため、本発明の鋼線の加工誘起α’分率は２０ｖｏｌ．％以上にする。一方、加工誘起α’の体積分率が９５ｖｏｌ．％を超える場合、伸線加工性と耐デラミネーション特性を低下させるため、上限を９５ｖｏｌ．％以下とする。好ましくは、３０ｖｏｌ．％以上である。また、好ましくは、７０ｖｏｌ．％以下である。 Work-induced martensite phase: 20-95 vol. %
Regarding the volume fraction of the processing-induced α ′ of the steel wire, 20 vol. If it is less than%, strength characteristics cannot be obtained. Therefore, the processing induced α ′ fraction of the steel wire of the present invention is 20 vol. % Or more. On the other hand, the volume fraction of processing-induced α ′ is 95 vol. %, The upper limit is 95 vol. In order to reduce the wire drawing workability and delamination resistance. % Or less. Preferably, 30 vol. % Or more. Moreover, Preferably, 70 vol. % Or less.
　なお、加工誘起マルテンサイト相は、強磁性を有し、一方、オーステナイト相は常磁性であるので、相率の測定には、電磁気的測定方法を用い、加工誘起マルテンサイト相をｖｏｌ．％で求めることができる。不可避的析出物相は存在したとしても１．０ｖｏｌ．％以下であり、加工誘起マルテンサイト相およびオーステナイト相に比べてごくわずかである。したがって、不可避的不純物相の１．０ｖｏｌ．％は無視できるので、オーステナイト相のｖｏｌ％は、１００％から加工誘起マルテンサイト相のｖｏｌ．％を引いた値となる。 Since the work-induced martensite phase has ferromagnetism, while the austenite phase is paramagnetic, the phase ratio is measured using an electromagnetic measurement method, and the work-induced martensite phase is vol. %. Even if an unavoidable precipitate phase is present, 1.0 vol. %, Which is negligible compared to the work-induced martensite phase and the austenite phase. Therefore, 1.0 vol. % Is negligible, the vol% of the austenite phase is from 100% to the vol. % Minus the value.
　鋼線の表層から２００μｍの位置におけるオーステナイト相のらせん転位分率：０．９以下
　鋼線の表層から２００μｍの位置におけるオーステナイト相のらせん転位分率は、耐デラミネーション特性に寄与する。そして、らせん転位分率が過剰に高くなると、変形し難くなり、耐デラミネーション特性が低下するため、その上限を０．９以下とする。好ましくは０．８以下、更に好ましくは０．７以下、更に好ましくは０．６以下である。らせん転位分率の下限は定める必要がないが、低すぎると強度が劣化するおそれがあるので、らせん転位分率は０．００１以上とするのが好ましい。好ましい下限は、０．０１であり、より好ましい下限は、０．０５である。 The screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire: 0.9 or less The screw dislocation fraction of the austenite phase at the position of 200 μm from the surface layer of the steel wire contributes to delamination resistance characteristics. And when the screw dislocation fraction becomes excessively high, it becomes difficult to deform and the delamination resistance characteristics deteriorate, so the upper limit is made 0.9 or less. Preferably it is 0.8 or less, More preferably, it is 0.7 or less, More preferably, it is 0.6 or less. There is no need to set the lower limit of the screw dislocation fraction, but if it is too low, the strength may deteriorate, so the screw dislocation fraction is preferably 0.001 or more. A preferred lower limit is 0.01, and a more preferred lower limit is 0.05.
　引張強さ：１６００ＭＰａ以上
　鋼線の引張強さが１６００ＭＰａ未満の場合、強度が劣化するため、本発明の効果が発現しない。そのため、引張強さの下限を１６００ＭＰａ以上とする。好ましくは１７００ＭＰａ以上であり、更に好ましくは１８００ＭＰａ以上、更に好ましくは１９００ＭＰａ以上である。 Tensile strength: 1600 MPa or more When the tensile strength of the steel wire is less than 1600 MPa, the strength of the steel wire deteriorates, and the effects of the present invention are not exhibited. Therefore, the lower limit of the tensile strength is set to 1600 MPa or more. Preferably it is 1700 MPa or more, More preferably, it is 1800 MPa or more, More preferably, it is 1900 MPa or more.
　デラミネーションを発生するせん断ひずみ速度：３．０×１０－４／ｓ以上
　次に、鋼線のデラミネーションを発生するせん断ひずみ速度が３．０×１０－４／ｓ未満の場合、耐デラミネーション特性が低くなるため、本発明の効果が発現しない。そのため、下限を３．０×１０－４／ｓ以上とする。好ましくは７．０×１０－４／ｓ以上であり、更に好ましくは２．０×１０－３／ｓ以上であり、更に好ましくは３．５×１０－３／ｓ以上である。 Shear strain rate for generating delamination: 3.0 × 10 −4 / s or more Next, when the shear strain rate for generating delamination of steel wire is less than 3.0 × 10 −4 / s, delamination resistance Since the characteristics are lowered, the effect of the present invention is not exhibited. Therefore, the lower limit is set to 3.0 × 10 −4 / s or more. It is preferably 7.0 × 10 −4 / s or more, more preferably 2.0 × 10 −3 / s or more, and further preferably 3.5 × 10 −3 / s or more.
　本実施形態に係る鋼線は、上述の本発明に係る線材と同様の化学組成を有し、また、Ｍｄ３０値が－２０～４０を満足する鋼線となる。さらに、加工誘起α’の体積分率が２０～９５ｖｏｌ．％となり、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率が０．９以下となるため、耐デラミネーション特性に優れた高強度ステンレス鋼線となる。そのうえ、引張強さが１６００以上となり、デラミネーションを発生するせん断ひずみ速度が３．０×１０－４／ｓ以上の鋼線となる。 The steel wire according to this embodiment has a chemical composition similar to that of the wire according to the present invention described above, and is a steel wire satisfying an Md30 value of −20 to 40. Further, the volume fraction of processing-induced α ′ is 20 to 95 vol. Since the screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire is 0.9 or less, it becomes a high-strength stainless steel wire excellent in delamination resistance characteristics. In addition, the tensile strength is 1600 or more, and the steel wire has a shear strain rate of 3.0 × 10 −4 / s or more that generates delamination.
　３．ステンレス鋼線の製造方法
　次に、本実施形態に係る高強度ステンレス鋼線および線材の製造方法について説明する。なお、本発明の高強度ステンレス鋼線および線材の製造方法は、以下に記載した条件に限るものではないことはもちろんである。 3. Next, the manufacturing method of the high-strength stainless steel wire and wire which concern on this embodiment is demonstrated. Of course, the manufacturing method of the high-strength stainless steel wire and wire of the present invention is not limited to the conditions described below.
　上記成分組成を有する鋼を溶製し、所定の径を有する鋳片に鋳造したのち、鋳片に対し熱間の線材圧延を行う。その後は、必要に応じて適宜、溶体化処理、酸洗を行い線材とする。 The steel having the above composition is melted and cast into a slab having a predetermined diameter, and then hot wire rolling is performed on the slab. Thereafter, solution treatment and pickling are performed as necessary to obtain a wire.
　本実施形態に係るステンレス鋼線は、上述の線材を冷間で伸線加工することにより得られる。具体的には、鋼線材または鋼線を下記の条件で伸線加工してステンレス鋼線を製造する。 The stainless steel wire according to the present embodiment is obtained by cold-drawing the above-described wire rod. Specifically, a steel wire or a steel wire is drawn under the following conditions to produce a stainless steel wire.
　総減面率：４０～９０％
　伸線加工における総減面率は、加工誘起α’量を確保し、高強度化するために、４０％以上とする。一方、総減面率が大きくなりすぎると、加工誘起α’量が増加しすぎて、耐デラミネーション特性が劣化するので、総減面率の上限は９０％とする。総減面率の下限は５０％とするのが好ましく、上限は８０％とするのが好ましい。 Total area reduction: 40-90%
The total area reduction rate in the wire drawing is 40% or more in order to secure the amount of machining-induced α ′ and increase the strength. On the other hand, if the total area reduction ratio becomes too large, the amount of processing-induced α ′ increases too much and the delamination resistance characteristics deteriorate, so the upper limit of the total area reduction ratio is 90%. The lower limit of the total area reduction is preferably 50%, and the upper limit is preferably 80%.
　パス回数：７回以上
　伸線加工は、パス回数が７回以上の多パス伸線により行う。パス回数とは、線材等のワークがダイスを通る回数を意味する。パス回数が少なすぎると、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率を上昇させ、耐デラミネーション特性を劣化させるため、パス回数７回以上とする。好ましくは、１５回以上とし、更に好ましくは、２１回以上とする。 Number of passes: 7 or more Wire drawing is performed by multi-pass wire drawing with a pass number of 7 or more. The number of passes means the number of times a workpiece such as a wire passes through a die. If the number of passes is too small, the screw dislocation ratio of the austenite phase at the 200 μm position is increased from the surface layer of the steel wire, and the delamination resistance characteristics are deteriorated. Preferably, it is 15 times or more, and more preferably 21 times or more.
　最終パスの減面率：０．５～２５％
　耐デラミネーション特性を向上するためには、最終パスの減面率を所定の範囲内で行うことが重要である。すなわち、最終パスの減面率は、大きすぎると、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率を上昇させ、耐デラミネーション特性を劣化させるため、２５％以下とする。好ましくは、２０％以下とし、更に好ましくは１０％以下、更に好ましくは５％以下である。一方、最終パスの減面率が０．５％未満となると、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率が上昇し、耐デラミネーション特性の向上が不十分となるため、下限を０．５％以上とする。 Area reduction rate of the final pass: 0.5-25%
In order to improve the delamination resistance, it is important to reduce the area reduction rate of the final pass within a predetermined range. That is, if the area reduction rate of the final pass is too large, the screw dislocation fraction of the austenite phase at the 200 μm position is increased from the surface layer of the steel wire, and the delamination resistance is deteriorated. The content is preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less. On the other hand, when the area reduction rate of the final pass is less than 0.5%, the screw dislocation fraction of the austenite phase at the 200 μm position increases from the surface layer of the steel wire, and the delamination resistance characteristics are insufficiently improved. Is 0.5% or more.
　以上の製造方法により、本実施形態に係る耐デラミネーション特性に優れる高強度ステンレス鋼線を得ることができる。 By the above manufacturing method, a high-strength stainless steel wire having excellent delamination resistance characteristics according to this embodiment can be obtained.
　以下に本発明の実施例について説明するが、実施例での条件は、本発明の実施可能性及び効果を確認するために採用した一条件例であり、本発明は、以下の実施例で用いた条件に限定されるものではない。本発明は、本発明の要旨を逸脱せず、本発明の目的を達成する限りにおいて、種々の条件を採用し得るものである。 Examples of the present invention will be described below, but the conditions in the examples are one example of conditions adopted to confirm the feasibility and effects of the present invention, and the present invention is used in the following examples. It is not limited to the conditions. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.
　表１および表２に実施例の鋼の化学組成（鋼種Ａ～ＡＲ）、オーステナイト（γ）相中のＭｄ３０値を示す。なお、表２中の下線は本発明範囲から外れているものを示す。 Tables 1 and 2 show the chemical compositions (steel types A to AR) of the steels of the examples and Md30 values in the austenite (γ) phase. In addition, the underline in Table 2 shows what is outside the scope of the present invention.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　これらの化学組成の鋼は、ステンレス鋼の安価溶製プロセスであるＡＯＤ溶製を想定し、１００ｋｇの真空溶解炉にて溶解し、φ１８０ｍｍの鋳片に鋳造した。得られた鋳片を１１００℃で２００分の加熱後、φ５．５ｍｍまで熱間の線材圧延（減面率：９９．９％）を行い、１０５０℃で熱間圧延を終了した。その直後に連続して、溶体化処理として１０５０℃で３分のインライン熱処理を実施して水冷し、酸洗を行い線材とした。その後、φ４．０ｍｍまで冷間で伸線加工を施した。得られたφ４．０ｍｍのステンレス鋼線に、１０５０℃で３分の中間ストランド焼鈍を施し、引き続きφ２．０ｍｍまで冷間で伸線加工を施し、高強度ステンレス鋼線とした。また、その際の総減面率は７５％、パス回数は７回、最終パスの減面率は１０％とした。 The steels having these chemical compositions were melted in a 100 kg vacuum melting furnace and cast into a slab of φ180 mm, assuming AOD melting, which is a cheap melting process for stainless steel. The obtained slab was heated at 1100 ° C. for 200 minutes, and then hot wire rolling (reduction rate: 99.9%) was performed to φ5.5 mm, and the hot rolling was terminated at 1050 ° C. Immediately thereafter, an in-line heat treatment was performed at 1050 ° C. for 3 minutes as a solution treatment, water-cooled, and pickled to obtain a wire. Thereafter, the wire was drawn cold to φ4.0 mm. The obtained φ4.0 mm stainless steel wire was subjected to intermediate strand annealing at 1050 ° C. for 3 minutes and subsequently subjected to cold drawing to φ2.0 mm to obtain a high-strength stainless steel wire. In this case, the total area reduction rate was 75%, the number of passes was 7, and the area reduction rate of the final pass was 10%.
　そして、上記方法により製造した鋼線について、下記の方法に従って、の加工誘起マルテンサイト分率（α’分率）、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率、引張強さ、デラミネーション発生のせん断ひずみ速度を評価した。 And about the steel wire manufactured by the above method, according to the following method, the processing induced martensite fraction (α ′ fraction), the screw dislocation fraction of the austenite phase at the 200 μm position from the surface layer of the steel wire, the tensile strength, The shear strain rate of delamination generation was evaluated.
［加工誘起マルテンサイト分率（加工誘起α’分率）］
　鋼線の加工誘起α’分率は、「鋼線」と「鋼線を１０５０℃×３分の熱処理した材料」を直流磁束計にて１．０×１０４Ｏｅの磁場を付与した時の飽和磁化値を測定し、以下の式（Ｂ）にて求めた。飽和磁化値の測定には、直流磁化特性試験装置（メトロン技研（株）製）を用いた。
　α’分率（ｖｏｌ．％）＝｛（σｓ－σ１０５０）／σｓ（ｂｃｃ）｝×１００　・・・（Ｂ）
　ここで、σｓは製品の飽和磁化値（Ｔ）、σ１０５０は製品を１０５０℃×３分の熱処理した材料の飽和磁化値（Ｔ）、σｓ（ｂｃｃ）はγが１００％マルテンサイト（α’）変態した時の飽和磁化値（下記式（Ｃ）で表される計算値）を示す。下記式（Ｃ）中のＣｒｅｑは下記式（Ｄ）で表される。
　　σｓ（ｂｃｃ）＝２．１４－０．０３０×Ｃｒｅｑ　・・・（Ｃ）
　　Ｃｒｅｑ＝Ｃｒ＋１．８×Ｓｉ＋Ｍｏ＋０．５×Ｎｉ＋０．９×Ｍｎ＋３．６（Ｃ＋Ｎ）＋１．２５×Ｐ＋２．９１×Ｓ　・・・（Ｄ） [Machining induced martensite fraction (machining induced α 'fraction)]
The processing-induced α ′ fraction of the steel wire is obtained when a magnetic field of 1.0 × 10 4 Oe is applied to the “steel wire” and “material obtained by heat-treating the steel wire at 1050 ° C. × 3 minutes” with a DC magnetometer. The saturation magnetization value was measured and obtained by the following formula (B). For measurement of the saturation magnetization value, a DC magnetization characteristic test apparatus (manufactured by Metron Engineering Co., Ltd.) was used.
α ′ fraction (vol.%) = {(σ s −σ 1050 ) / σ s (bcc)} × 100 (B)
Here, σ s is the saturation magnetization value (T) of the product, σ 1050 is the saturation magnetization value (T) of the material obtained by heat-treating the product at 1050 ° C. × 3 minutes, σ s (bcc) is the martensite (γ is 100%) α ′) shows a saturation magnetization value (calculated value represented by the following formula (C)) when transformed. Creq in the following formula (C) is represented by the following formula (D).
σ s (bcc) = 2.14−0.030 × Creq (C)
Creq = Cr + 1.8 × Si + Mo + 0.5 × Ni + 0.9 × Mn + 3.6 (C + N) + 1.25 × P + 2.91 × S (D)
［鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率］
　鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率は、Ｘ線ラインプロファイル解析で測定した。鋼線のＬ断面において、鋼線の表層から２００μｍ位置において、Ｘ線回折にてＣｕＫα線を用いて測定を行い、（１１１）、（２００）、（２２０）（３１１）の半価幅を測定し、得られた半価幅を以下のｍｏｄｉｆｉｅｄ　Ｗｉｌｌｉａｍｓｏｎ－Ｈａｌｌ式（Ｅ）へ代入する。
　ΔＫ＝０．９／Ｄ＋√（（πＭ２ｂ２ρ）／２）ＫＣ１／２＋Ｏ（Ｋ２Ｃ） ・・・（Ｅ） [Screw dislocation fraction of austenite phase at 200 μm position from the surface layer of steel wire]
The screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire was measured by X-ray line profile analysis. In the L cross section of the steel wire, at a position of 200 μm from the surface layer of the steel wire, measurement is performed using CuKα ray by X-ray diffraction, and the half widths of (111), (200), (220) and (311) are measured. Then, the obtained half-value width is substituted into the following modified Williamson-Hall equation (E).
ΔK = 0.9 / D + √ ((πM 2 b 2 ρ) / 2) KC 1/2 + O (K 2 C) (E)
　なお、式（Ｅ）において、Ｄ は結晶子サイズ（ｎｍ）、ρは転位密度（ｍ－２），ｂはバーガースベクトルの大きさ（ｎｍ）、Ｍ は転位密度ρ と転位の相互作用距離Ｒｅ（ｎｍ）に関する定数であり，Ｃ は転位の平均コントラスト因子である。また、ＫおよびΔＫは、下記の通りである。
　Ｋ＝２ｓｉｎθ／λ、
　ΔＫ＝２βｃｏｓθ／λ In Equation (E), D is the crystallite size (nm), ρ is the dislocation density (m −2 ), b is the Burgers vector size (nm), and M is the dislocation density ρ and the dislocation interaction distance Re. (Nm) is a constant and C is the average contrast factor of dislocations. K and ΔK are as follows.
K = 2 sin θ / λ,
ΔK = 2βcos θ / λ
　上記式において、β、θおよびλは、それぞれ各回折線の半値幅（ｒａｄ）、ブラッグ反射角（ｒａｄ）およびＸ線波長（ＣｕＫα＝０．１５４０５ｎｍ）である。
　ここで、式（Ｅ）の両辺を２乗し，高次項である Ｏ（Ｋ２Ｃ）を無視し，α＝（０．９／Ｄ）２、γ＝πＭ２ｂ２ρ／２ とすると、式（Ｆ）が得られる。
　[（ΔＫ）２－α]/Ｋ２＝γＣ ・・・（Ｆ） In the above equation, β, θ, and λ are the half width (rad), Bragg reflection angle (rad), and X-ray wavelength (CuKα = 0.15405 nm) of each diffraction line, respectively.
Here, if both sides of the equation (E) are squared, the higher order term O (K 2 C) is ignored, and α = (0.9 / D) 2 and γ = πM 2 b 2 ρ / 2. Equation (F) is obtained.
[(ΔK) 2 −α] / K 2 = γC (F)
　上記式において、Ｃ＝Ｃｈ００（１－ｑＨ２）である。そして、ｑは転位の種類とその割合を含むパラメータであり、Ｈ（＝（ｈ２ｋ２＋ｈ２ｌ２＋ｋ２ｌ２）／（ｈ２＋ｋ２＋ｌ２）２）は回折線の指数ｈ, ｋ, ｌ の関数である。Ｃｈ００は弾性定数から求められる定数である。
上記のｑ値を測定し、下記式（Ｇ）から、オーステナイトのらせん転位分率Ｓを算出することができる。
　Ｓ＝（ｑ－ｑｅ）／（ｑｓ－ｑｅ）・・・（Ｇ） In the above formula, a C = C h00 (1-qH 2). Q is a parameter including the type of dislocation and its ratio, and H (= (h 2 k 2 + h 2 l 2 + k 2 l 2 ) / (h 2 + k 2 + l 2 ) 2 ) is an index h of diffraction lines. , k, l. C h00 is a constant obtained from the elastic constant.
The q value is measured, and the screw dislocation fraction S of austenite can be calculated from the following formula (G).
S = (q−q e ) / (q s −q e ) (G)
　上記式において、ｑｅとｑｓはそれぞれ１００％刃状転位、らせん転位の場合のｑ値であり、弾性定数から決まる定数である。 In the above formula, q e and q s are q values in the case of 100% edge dislocation and screw dislocation, respectively, and are constants determined from elastic constants.
［引張強さ］
　鋼線の引張強さは、ＪＩＳ　Ｚ　２２４１の引張試験での引張強さにて評価した。 [Tensile strength]
The tensile strength of the steel wire was evaluated by the tensile strength in the tensile test of JIS Z2241.
［デラミネーション発生のせん断ひずみ速度］
　鋼線のデラミネーション発生のせん断ひずみ速度は、捻回試験にて評価した。捻回試験は、鋼線の線径ｄを２．０ｍｍ、チャック間距離Ｌを１５０ｍｍとし、回転速度Ｒ（ｒｐｍ）を変化させ、最表層のせん断歪み速度γ’（／ｓ）を制御し、捻回試験を行った。種々のせん断歪み速度にて、０．３％耐力以降にトルク低下の生じたものをデラミネーション発生とし、デラミネーションを発生したせん断歪み速度を耐デラミネーション特性の指標とした。 [Shear strain rate for delamination]
The shear strain rate at which delamination occurred in the steel wire was evaluated by a twist test. In the twist test, the wire diameter d of the steel wire is 2.0 mm, the distance L between chucks is 150 mm, the rotational speed R (rpm) is changed, and the shear strain speed γ ′ (/ s) of the outermost layer is controlled. A torsion test was performed. At various shear strain rates, the occurrence of torque reduction after 0.3% proof stress was regarded as delamination occurrence, and the shear strain rate at which delamination occurred was used as an index of delamination resistance characteristics.
　その評価結果を表３および表４に示す。 The evaluation results are shown in Table 3 and Table 4.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表３に示すとおり、本発明例１～３３の鋼線において、加工誘起α’分率は２０～９０ｖｏｌ．％であり、引張強さは１６００ＭＰａ以上であり、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率は０．９以下であった。また、本発明例１～３３のデラミネーション発生のせん断ひずみ速度は、３．０×１０－４／ｓ以上であった。一方、比較例３４～４８の鋼線は、引張強さ、および、耐デラミネーション特性のいずれかの性能が劣化していた。なお、比較例Ｎｏ．４１においては、耐食性不良であったので、引張強さとデラミネーションについては評価をしなかった。 As shown in Table 3, in the steel wires of Invention Examples 1 to 33, the processing-induced α ′ fraction was 20 to 90 vol. The tensile strength was 1600 MPa or more, and the screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire was 0.9 or less. In addition, the shear strain rate of delamination generation in Invention Examples 1 to 33 was 3.0 × 10 −4 / s or more. On the other hand, in the steel wires of Comparative Examples 34 to 48, either the tensile strength or the delamination resistance performance was deteriorated. Comparative Example No. In No. 41, since the corrosion resistance was poor, the tensile strength and delamination were not evaluated.
　次に、製造条件の影響について調査した。 Next, we investigated the effect of manufacturing conditions.
　表１に示す鋼種Ｒを用いて、上記と同様の方法で作製した、種々の径を有するステンレス鋼線を表５に示す伸線加工条件で伸線することにより、φ２．０ｍｍの鋼線を作製した。いずれの例においても鋼線の最終線径がφ２．０ｍｍとなるように、伸線加工に供する鋼線径および最終パス前の鋼線径を調整した。そして、得られた鋼線について、前記と同様の方法で、加工誘起マルテンサイト（α’）の体積率、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率、引張強さおよびデラミネーション発生のせん断ひずみ速度を測定し、評価した。評価結果を表５および表６に示す。 By using the steel type R shown in Table 1 and drawing the stainless steel wires having various diameters produced in the same manner as described above under the drawing conditions shown in Table 5, a φ2.0 mm steel wire was obtained. Produced. In either example, the steel wire diameter used for wire drawing and the steel wire diameter before the final pass were adjusted so that the final wire diameter of the steel wire was 2.0 mm. Then, with respect to the obtained steel wire, the volume ratio of work-induced martensite (α ′), the screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire, the tensile strength and the delamination are performed in the same manner as described above. The generated shear strain rate was measured and evaluated. The evaluation results are shown in Table 5 and Table 6.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　試験Ｎｏ．４５～５３に示す本発明例の鋼線は、いずれも加工誘起α’分率は２０～９０ｖｏｌ．％であり、鋼線の表層から２００μｍ位置におけるオーステナイト相のらせん転位分率は０．９以下であり、引張強さが１６００ＭＰａ以上、デラミネーション発生のせん断ひずみ速度は、３．０×１０－４／ｓ以上であった。これに対して、伸線加工を適切な条件で行わなかった比較例５４～５８の鋼線は、引張強さ、および、耐デラミネーション特性のいずれかの性能が劣化していた。 Test No. The steel wires of the examples of the present invention shown in 45 to 53 all have a processing-induced α ′ fraction of 20 to 90 vol. %, The austenite phase screw dislocation fraction at a position of 200 μm from the surface layer of the steel wire is 0.9 or less, the tensile strength is 1600 MPa or more, and the shear strain rate at which delamination occurs is 3.0 × 10 −4. / S or more. On the other hand, in the steel wires of Comparative Examples 54 to 58 in which the wire drawing was not performed under appropriate conditions, the performance of either tensile strength or delamination resistance was deteriorated.
　本発明によれば、耐デラミネーション特性に優れる高強度ステンレス鋼線を提供することができるので、産業上極めて有用である。このステンレス鋼線をばね部品などに適用することで、耐デラミネーション特性に優れるばね部品などを提供することができる。なお、ばね部品とは、自動車用ばねや産業機械用ばね、家電用ばね等を意味する。 According to the present invention, a high-strength stainless steel wire having excellent delamination resistance characteristics can be provided, which is extremely useful industrially. By applying this stainless steel wire to a spring part or the like, it is possible to provide a spring part or the like having excellent delamination resistance characteristics. In addition, a spring component means the spring for motor vehicles, the spring for industrial machines, the spring for household appliances, etc.

Claims (8)

  1. 　質量％で、
    Ｃ　：０．００５～０．１５％、
    Ｓｉ：０．１～４．０％、
    Ｍｎ：０．１～８．０％、
    Ｎｉ：１．０～１０．０％、
    Ｃｒ：１３．０～２０．０％、
    Ｍｏ：０．０１～３．００％、
    Ｃｕ：０．８０％超～４．００％、
    Ｎ　：０．００５～０．２０％、
    Ｖ　：０～２．５％、
    Ｂ　：０～０．０１２％、
    Ａｌ：０～２．０％、
    Ｗ　：０～２．５％、
    Ｇａ：０～０．０５００％、
    Ｃｏ：０～２．５％、
    Ｓｎ：０～２．５％、
    Ｔｉ：０～１．０％、
    Ｎｂ：０～２．５％、
    Ｔａ：０～２．５％、
    Ｃａ：０～０．０１２％、
    Ｍｇ：０～０．０１２％、
    Ｚｒ：０～０．０１２％、
    ＲＥＭ：０～０．０５％、
    残部がＦｅおよび不可避的不純物からなり、
    　下記式（ａ）で示されるＭｄ３０が－２０～４０である、
    ステンレス鋼線用の線材。
    　Ｍｄ３０＝５５１－４６２（Ｃ＋Ｎ）－９．２Ｓｉ－８．１Ｍｎ－２９（Ｎｉ＋Ｃｕ）－１３．７Ｃｒ－１８．５Ｍｏ　　…　（ａ）
    　但し、式（ａ）中の元素記号は、当該元素の鋼中における含有量（質量％）を意味する。また、式（ａ）中の元素の含有量が０％である場合は、該当記号箇所には「０」を代入して算出する。     % By mass
    C: 0.005 to 0.15%,
    Si: 0.1 to 4.0%,
    Mn: 0.1 to 8.0%,
    Ni: 1.0-10.0%,
    Cr: 13.0-20.0%,
    Mo: 0.01 to 3.00%,
    Cu: more than 0.80% to 4.00%,
    N: 0.005 to 0.20%,
    V: 0 to 2.5%
    B: 0 to 0.012%,
    Al: 0 to 2.0%,
    W: 0 to 2.5%
    Ga: 0 to 0.0500%,
    Co: 0 to 2.5%,
    Sn: 0 to 2.5%,
    Ti: 0 to 1.0%,
    Nb: 0 to 2.5%,
    Ta: 0 to 2.5%,
    Ca: 0 to 0.012%,
    Mg: 0 to 0.012%,
    Zr: 0 to 0.012%,
    REM: 0 to 0.05%,
    The balance consists of Fe and inevitable impurities,
    Md30 represented by the following formula (a) is -20 to 40,
    Wire for stainless steel wire.
    Md30 = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
    However, the element symbol in Formula (a) means content (mass%) in the steel of the said element. In addition, when the content of the element in the formula (a) is 0%, “0” is substituted into the corresponding symbol portion for calculation.
  2. 　更に質量％で、
    Ｖ　：０．００１～２．５％、
    Ｂ　：０．００１～０．０１２％、
    Ａｌ：０．００１～２．０％、
    Ｗ　：０．０５～２．５％、
    Ｇａ：０．０００４～０．０５００％、
    Ｃｏ：０．０５～２．５％、
    Ｓｎ：０．０１～２．５％、
    Ｔｉ：０．０１～１．０％、
    Ｎｂ：０．０１～２．５％、
    Ｔａ：０．０１～２．５％、
    Ｃａ：０．０００２～０．０１２％、
    Ｍｇ：０．０００２～０．０１２％、
    Ｚｒ：０．０００２～０．０１２％および
    ＲＥＭ：０．０００２～０．０５％から選択される一種以上を含有する、
    請求項１に記載のステンレス鋼線用の線材。     In addition,
    V: 0.001 to 2.5%,
    B: 0.001 to 0.012%,
    Al: 0.001 to 2.0%,
    W: 0.05-2.5%,
    Ga: 0.0004 to 0.0500%,
    Co: 0.05-2.5%
    Sn: 0.01 to 2.5%,
    Ti: 0.01 to 1.0%,
    Nb: 0.01 to 2.5%,
    Ta: 0.01 to 2.5%,
    Ca: 0.0002 to 0.012%,
    Mg: 0.0002 to 0.012%,
    One or more selected from Zr: 0.0002 to 0.012% and REM: 0.0002 to 0.05%,
    The wire material for stainless steel wires according to claim 1.
  3. 　質量％で、
    Ｃ　：０．００５～０．１５％、
    Ｓｉ：０．１～４．０％、
    Ｍｎ：０．１～８．０％、
    Ｎｉ：１．０～１０．０％、
    Ｃｒ：１３．０～２０．０％、
    Ｍｏ：０．０１～３．００％、
    Ｃｕ：０．８０％超～４．００％、
    Ｎ　：０．００５～０．２０％、
    Ｖ　：０～２．５％、
    Ｂ　：０～０．０１２％、
    Ａｌ：０～２．０％、
    Ｗ　：０～２．５％、
    Ｇａ：０～０．０５００％、
    Ｃｏ：０～２．５％、
    Ｓｎ：０～２．５％、
    Ｔｉ：０～１．０％、
    Ｎｂ：０～２．５％、
    Ｔａ：０～２．５％、
    Ｃａ：０～０．０１２％、
    Ｍｇ：０．０１２％、
    Ｚｒ：０～０．０１２％、
    ＲＥＭ：０～０．０５％、
    残部がＦｅおよび不可避的不純物からなり、
    　下記式（ａ）で示されるＭｄ３０が－２０～４０であり、
    　加工誘起マルテンサイト相が２０～９５ｖｏｌ．％である金属組織を有し、
    　鋼線の表層から２００μｍの位置におけるオーステナイト相のらせん転位分率が０．９以下である、
    ステンレス鋼線。
    　Ｍｄ３０＝５５１－４６２（Ｃ＋Ｎ）－９．２Ｓｉ－８．１Ｍｎ－２９（Ｎｉ＋Ｃｕ）－１３．７Ｃｒ－１８．５Ｍｏ　　…　（ａ）
    　但し、式（ａ）中の元素記号は、当該元素の鋼中における含有量（質量％）を意味する。また、式（ａ）中の元素の含有量が０％である場合は、該当記号箇所には「０」を代入して算出する。     % By mass
    C: 0.005 to 0.15%,
    Si: 0.1 to 4.0%,
    Mn: 0.1 to 8.0%,
    Ni: 1.0-10.0%,
    Cr: 13.0-20.0%,
    Mo: 0.01 to 3.00%,
    Cu: more than 0.80% to 4.00%,
    N: 0.005 to 0.20%,
    V: 0 to 2.5%
    B: 0 to 0.012%,
    Al: 0 to 2.0%,
    W: 0 to 2.5%
    Ga: 0 to 0.0500%,
    Co: 0 to 2.5%,
    Sn: 0 to 2.5%,
    Ti: 0 to 1.0%,
    Nb: 0 to 2.5%,
    Ta: 0 to 2.5%,
    Ca: 0 to 0.012%,
    Mg: 0.012%,
    Zr: 0 to 0.012%,
    REM: 0 to 0.05%,
    The balance consists of Fe and inevitable impurities,
    Md30 represented by the following formula (a) is −20 to 40,
    The processing-induced martensite phase is 20 to 95 vol. % Having a metallographic structure,
    The screw dislocation fraction of the austenite phase at a position of 200 μm from the surface layer of the steel wire is 0.9 or less,
    Stainless steel wire.
    Md30 = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
    However, the element symbol in Formula (a) means content (mass%) in the steel of the said element. In addition, when the content of the element in the formula (a) is 0%, “0” is substituted into the corresponding symbol portion for calculation.
  4. 　更に質量％で、
    Ｖ　：０．００１～２．５％、
    Ｂ　：０．００１～０．０１２％、
    Ａｌ：０．００１～２．０％、
    Ｗ　：０．０５～２．５％、
    Ｇａ：０．０００４～０．０５００％、
    Ｃｏ：０．０５～２．５％、
    Ｓｎ：０．０１～２．５％、
    Ｔｉ：０．０１～１．０％、
    Ｎｂ：０．０１～２．５％、
    Ｔａ：０．０１～２．５％、
    Ｃａ：０．０００２～０．０１２％、
    Ｍｇ：０．０００２～０．０１２％、
    Ｚｒ：０．０００２～０．０１２％および
    ＲＥＭ：０．０００２～０．０５％から選択される一種以上を含有する、
    請求項３に記載のステンレス鋼線。     In addition,
    V: 0.001 to 2.5%,
    B: 0.001 to 0.012%,
    Al: 0.001 to 2.0%,
    W: 0.05-2.5%,
    Ga: 0.0004 to 0.0500%,
    Co: 0.05-2.5%
    Sn: 0.01 to 2.5%,
    Ti: 0.01 to 1.0%,
    Nb: 0.01 to 2.5%,
    Ta: 0.01 to 2.5%,
    Ca: 0.0002 to 0.012%,
    Mg: 0.0002 to 0.012%,
    One or more selected from Zr: 0.0002 to 0.012% and REM: 0.0002 to 0.05%,
    The stainless steel wire according to claim 3.
  5. 　前記金属組織が、オーステナイト相を含む、
    請求項３または請求項４に記載のステンレス鋼線。     The metal structure includes an austenite phase;
    The stainless steel wire according to claim 3 or claim 4.
  6. 　引張強さが１６００ＭＰａ以上、デラミネーションを発生するせん断ひずみ速度が３．０×１０－４／ｓ以上である、
    請求項３から請求項５までの何れか一項に記載のステンレス鋼線。     The tensile strength is 1600 MPa or more, and the shear strain rate for generating delamination is 3.0 × 10 −4 / s or more.
    The stainless steel wire according to any one of claims 3 to 5.
  7. 　請求項１または請求項２に記載の線材を伸線加工して請求項３から請求項６までの何れか一項に記載のステンレス鋼線を製造する方法であって、
    　前記伸線加工を、総減面率：４０～９０％、パス回数：７回以上、最終パスの減面率：０．５～２５％の条件で行う、ステンレス鋼線の製造方法。     A method for producing the stainless steel wire according to any one of claims 3 to 6 by drawing the wire according to claim 1 or 2.
    A method for producing a stainless steel wire, wherein the wire drawing is performed under conditions of a total area reduction: 40 to 90%, number of passes: 7 times or more, and area reduction of the final pass: 0.5 to 25%.
  8. 　請求項３から請求項６までの何れか一項に記載のステンレス鋼線を用いたばね部品。
          A spring component using the stainless steel wire according to any one of claims 3 to 6.
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JP2018021260A (en) * 2016-07-25 2018-02-08 新日鐵住金ステンレス株式会社 Thick-sized high-strength stainless steel wire and method for producing the same, and spring component
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WO2022180869A1 (en) * 2021-02-24 2022-09-01 日鉄ステンレス株式会社 Austenitic stainless steel material, method for producing same, and leaf spring
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WO2024018520A1 (en) * 2022-07-19 2024-01-25 日鉄ステンレス株式会社 High strength stainless steel wire and spring

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