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HK1069190A1 - High strength stainless steel wire excellent in frequency of torque and modulus of rigidity and method for production thereof - Google Patents

High strength stainless steel wire excellent in frequency of torque and modulus of rigidity and method for production thereof Download PDF

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Publication number
HK1069190A1
HK1069190A1 HK05101661A HK05101661A HK1069190A1 HK 1069190 A1 HK1069190 A1 HK 1069190A1 HK 05101661 A HK05101661 A HK 05101661A HK 05101661 A HK05101661 A HK 05101661A HK 1069190 A1 HK1069190 A1 HK 1069190A1
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Hong Kong
Prior art keywords
steel wire
cold drawing
wire
modulus
equivalent
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HK05101661A
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Chinese (zh)
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HK1069190B (en
Inventor
Koji Takano
Kazuhisa Takeuchi
Yoshinori Tada
Yoshinori Tanimoto
Takayuki Akizuki
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Nippon Steel Corporation
Nippon Seisen Co., Ltd.
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Application filed by Nippon Steel Corporation, Nippon Seisen Co., Ltd. filed Critical Nippon Steel Corporation
Publication of HK1069190A1 publication Critical patent/HK1069190A1/en
Publication of HK1069190B publication Critical patent/HK1069190B/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
    • B23K35/262—Sn as the principal constituent
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/10—Modifying the physical properties of iron or steel by deformation by cold working of the whole cross-section, e.g. of concrete reinforcing bars
    • 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
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/36—Electric or electronic devices
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Heat Treatment Of Steel (AREA)
  • Metal Extraction Processes (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Abstract

A high strength stainless steel wire excellent in ductility-toughness and modulus of rigidity, which has a chemical composition, in mass %, C: 0.03 to 0.14 %, Si: 0.1 to 4.0 %, Mn: 0.1 to 5.0 %, Ni: 5.0 to 9.0 %, Cr: 14.0 to 19.0 %, N: 0.005 to 0.20 %, O: 0.001 to 0.01 %, S: 0.0001 to 0.012 % and balance: Fe and inevitable impurities, provided that the value of (2C + N) is 0.17 to 0.32 %, that the value of Ni equivalent of the following formula (1): Ni equivalent (%) = Ni + 0.65Cr + 0.98Mo + 1.06Mn + 0.35Si + 12.6(C + N) (1) is 20 to 24, and that H <= 4 ppm. The production of the high strength stainless steel wire is achieved through the control of the amounts of basic components, oxygen, hydrogen and sulfur as mentioned above, the formation of finer crystal grains, and the toughness improving effect of ausforming by cold wire drawing.

Description

High-strength stainless steel wire having excellent number of twists and modulus of rigidity and method for producing same
Technical Field
The present invention relates to a high-strength stainless steel wire, and more particularly, to a technique for improving ductility (ductility, toughness) and a modulus of rigidity of a high-strength austenitic stainless steel wire by cold drawing.
Background
Conventionally, high-strength stainless steel wires for springs have a problem of longitudinal cracking (age cracking) during cold drawing, and there has been proposed a technique for preventing the occurrence of this problem by specifying the composition, the amount of hydrogen, and the amount of martensite generated by strain after drawing (Japanese patent application laid-open No. Hei 10-121208).
In addition, as for the technique of strengthening and toughening a steel material (the technique of improving ductility), conventionally, a method of an austenite-forming heat treatment of cooling an austenite structure to transform it into martensite in a hot or warm state after working has been studied for carbon steel. (for example, Japan society of metals, Vol.27, No. 8, 1988, p623 ~ 639). However, this method is greatly limited because it requires the austenite structure to be processed at a hot temperature or a warm temperature region and then immediately quenched, and thus has hardly been industrially popularized.
In the prior art, no study has been made on the strategy of improving the ductility (ductility and toughness) and the modulus of rigidity of stainless steel wires for springs and the like. In particular, the number of twists is important as an index of ductility of a steel wire for a high-strength spring.
In the use of high-strength stainless steel springs, it is the most important object to improve the ductility (number of twists) and the modulus of stiffness of high-strength stainless steel wires from the viewpoints of preventing breakage accidents and improving the spring constant, and making them stable and lightweight.
Accordingly, an object of the present invention is to provide a high-strength stainless steel wire having remarkably improved ductility and modulus of rigidity by utilizing the effects of grain refinement and strengthening by austenite shape heat treatment by cold drawing in addition to the predetermined basic components and purity (oxygen and sulfur), and a method for manufacturing the same.
Disclosure of Invention
The present inventors have made various studies to solve the above problems, and as a result, have found that a high-strength stainless steel wire having significantly improved ductility and modulus of rigidity can be stably obtained by defining the conditions of the structure, strength, and cold drawing process, and utilizing the effects of grain refinement and austenite shape heat treatment, in addition to the basic components and purity (oxygen and sulfur) of the matrix metal in austenitic stainless steel. The present invention has been completed based on such findings.
That is, the gist of the present invention is as follows.
The present invention is a high-strength stainless steel wire excellent in the number of twists and the modulus of rigidity, characterized by containing, in mass%, C: 0.03 to 0.14%, Si: 0.1-4.0%, Mn: 0.1 to 5.0%, Ni: 5.0-9.0%, Cr: 14.0 to 19.0%, N: 0.005-0.20%, 0: 0.001-0.01%, S: 0.0001 to 0.012%, further comprising any 1 or more than 1 of A, B described below, further comprising C if necessary, and the balance of Fe and inevitable impurities, and wherein 2C + N is 0.17 to 0.32%, the value of Ni equivalent (%) in the following formula (1) is 20 to 24, H is not more than 4ppm,
a: any 1 or more than 1 of Al, Nb, Ti, Zr, Ta and W, which are respectively 0.01-0.30%;
b: v is 0.1-0.5%;
c: mo is 0.2-3.0%;
ni equivalent (mass%) + Ni +0.65Cr +0.98Mo +1.06Mn +0.35Si +12.6(C + N)
(1)
In addition, the steel wire of the present invention preferably has a GI value of 30 or less in the following formula (2).
GI(％)＝16C+2Mn+9Ni-3Cr+8Mo+15N (2)
The present invention is a method for producing a high-strength stainless steel wire having excellent torsional modulus and rigidity modulus, comprising the steps of mixing, in mass%, a steel wire containing C: 0.03 to 0.14%, Si: 0.1-4.0%, Mn: 0.1 to 5.0%, Ni: 5.0-9.0%, Cr: 14.0 to 19.0%, N: 0.005-0.20%, O: 0.001-0.01%, S: 0.0001 to 0.012%, the balance being Fe and unavoidable impurities, and 0.17 to 0.32% 2C + N, and 0.17 to 0.32% Ni equivalent (%) of the following formula (1) is hot-rolled into a wire rod and subjected to solution treatment, or the wire rod is subjected to solution treatment 1 or more times and cold drawing to form a rough wire, and then cold finishing is performed to produce a steel wire, wherein in a series of steps of performing cold finishing to produce a steel wire, the final solution treatment is performed at least in an atmosphere not containing hydrogen gas so that H in the steel is 4ppm or less, and cold finishing drawing is performed in a range of formula (4) in accordance with a drawing amount ε represented by formula (3).
Ni equivalent (%) ═ Ni +0.65Cr +0.98Mo +1.06Mn +0.35Si +12.6(C + N)
(1)
ε＝ln(A0/A) (3)
Wherein A is0: cross-sectional area of wire rod or thick wire before cold-drawing
A: cross-sectional area of steel wire after cold drawing
0.15X (Ni equivalent) -2.28. ltoreq. epsilon. 0.15X (Ni equivalent) -0.88 (4)
In the above production method of the present invention, it is preferable that the series of steps is added with a step prior to the solution treatment in an atmosphere not containing hydrogen gas, and in the addition step, the dehydrogenation treatment is performed in an atmosphere not containing hydrogen gas and having a temperature of 200 to 600 ℃.
In the production method of the present invention, the steel, the wire rod, or the thick wire may further contain any one or more selected from the following A, B, C in mass%.
A: any 1 or more than 1 of Al, Nb, Ti, Zr, Ta and W, 0.01-0.30% respectively
B: v is 0.1 to 0.5 percent
C: mo is 0.2-3.0%
In the production method of the present invention, the austenite average grain size before cold drawing of the wire rod or the thick wire is preferably 30 μm or less.
Detailed Description
First, the composition ranges of the stainless steel wire of the present invention will be described. In the following description,% represents mass% as a whole unless otherwise specified.
In order to obtain high strength after cold drawing together with N, 0.03% or more of C is added. However, if the amount of Cr added exceeds 0.14%, Cr carbide precipitates at grain boundaries to lower the ductility, so that the amount of Cr carbide is limited to 0.14%.
For deoxidation, 0.1% or more of Si is added. However, when the amount exceeds 4.0%, the effect is saturated, the productivity is poor, and the ductility is poor, so that the upper limit is 4.0%.
For deoxidation and adjustment of Ni equivalent, 0.1% or more of Mn is added. However, when the amount exceeds 5.0%, the rigidity modulus decreases, so that the upper limit is 5.0%.
In order to secure ductility and adjust Ni equivalent, 5.0% or more of Ni is added. However, when the amount exceeds 9.0%, the rigidity modulus decreases, so that the upper limit is 5.0%.
In order to secure corrosion resistance and adjust the Ni equivalent, 14.0% or more of Cr is added. However, when the amount exceeds 19.0%, the ductility is deteriorated, so that the amount is limited to 19.0%.
In order to obtain high strength after cold drawing together with C, 0.005% or more N is added. However, when the amount of the additive exceeds 0.20%, pores are formed during production, and the productivity is remarkably deteriorated, so that the amount is limited to 0.20%.
In order to ensure the number of twists, 0 is defined to be 0.01% or less than 0.01%. However, if the content is controlled to 0.001% or less, the industrial cost increases and the price/performance ratio deteriorates, so the lower limit is set to 0.001%.
In order to ensure the number of twists, S is limited to 0.012% or less than 0.012%. However, if the content is controlled to 0.0001% or less, the lower limit is set to 0.0001% because the industrial cost increases and the cost performance ratio deteriorates.
In order to ensure ductility, the hydrogen content in the steel is 4ppm or less. Particularly preferably 1.5ppm or less or 1.5ppm or less.
Al, Nb, Ti, Zr, Ta, and W can form fine carbonitrides, stably refine austenite grains after solution treatment of the steel wire, and improve ductility, and therefore, any 1 or more than 1 of 0.01% or more is added, respectively, as necessary. However, when 0.30% or more is added, the effect is saturated; not only uneconomical but also reduced ductility, so that it is limited to 0.30%.
In particular, Al and Nb are effective because they improve hot workability and contribute to high strength by the precipitation strengthening effect.
V can form fine carbonitride like Al, Nb, Ti, Zr, Ta, W, and stably refine austenite grains after solution treatment of the steel wire to improve ductility, and is added in an amount of 0.1% or more as necessary. However, when 0.5% or more is added, the effect is saturated, and the ductility is reduced, so that the upper limit is 0.5%.
Mo is effective against corrosion, and therefore 0.2% or more or 0.2% is added as necessary. However, when the amount of the additive exceeds 3.0%, the effect is saturated, and the elastic modulus is decreased, so that the upper limit is 3.0%. Particularly preferably 2.0% or less, or 2.0% or less.
Cu suppresses work hardening of the austenite structure and lowers the strength of the steel wire after cold drawing, and therefore is preferably lowered to 0.8% or less, if necessary.
P is an element that reduces ductility, and therefore, it is preferably reduced to 0.02% or less, if necessary.
The strength of the steel wire after cold drawing and the amount of strain-induced martensite will be described below.
Cold wire drawing processThe tensile strength of the steel wire is lower than 1700N/mm2In the case (2), since ductility is basically high, the effect of the present invention cannot be remarkably exhibited. On the other hand, the tensile strength of the steel wire after cold drawing was 1700N/mm2Or 1700N/mm2In the case of the above high-strength material, the ductility is lowered, and therefore the effects of the present invention, such as grain refinement and austenite heat treatment, can be clarified. Therefore, it is preferable to limit the tensile strength of the steel wire after cold drawing to 1700N/m2Or 1700N/mm2The above. Particularly preferably 1900N/mm2Or 1900N/mm2Above, but the upper limit value is 2800N/mm2It is preferable.
When the amount of strain-induced martensite in the steel wire after cold drawing is less than 20%, the tensile strength of the steel wire after cold drawing is usually less than 1700N/mm2The effect of high ductility of the present invention is not remarkably exhibited, and the modulus of rigidity is also low. Therefore, the amount of strain-induced martensite is preferably 20% or more. On the other hand, when the amount of strain-induced martensite after cold drawing exceeds 80%, the amount of tough martensite itself subjected to austenite-type hot working decreases, and the ductility decreases. Therefore, the upper limit is preferably 80%. In particular, in order to maximize the strength and rigidity of the steel wire by the austenite heat treatment, it is preferable to limit the amount of strain-induced martensite in the steel wire after the cold drawing to 40% to 70%.
The amount (volume%) of strain-induced martensite can be measured, for example, by a saturation magnetic flux density measured by a dc magnetization characteristic measuring device or the like. In addition, in the case of measurement by a simple ferrite instrument (フエライトメ - タ), wire diameter correction is required.
The following describes the 2C + N amount (%) defined in the present invention, and the formulae (1) and (2).
The 2C + N (%) was obtained by examining the effect of C, N on the tensile strength of the steel wire after cold drawing. In order to ensure the tensile strength of the steel wire after cold drawing at 1700N/mm2Or 1700N/mm2In this case, 2C + N is limited to 0.17 (%) or more. However, if it exceeds 0.32 (%), the ductility is lowered, so that the upper limit is 0.32 (%). Particularly from stable high strength (tensile strength is more than or equal to 1900N/mm)2) And 0.20 to 0.30 (%) from the viewpoint of high ductility.
The Ni equivalent of formula (1) was obtained as a result of examining the influence of each element on the ductility of the steel wire after cold drawing, and indicates the degree of influence of the effective element on the ductility.
Ni equivalent (%) ═ Ni +0.65Cr +0.98Mo +1.06Mn +0.35Si +12.6(C + N)
(1)
When the Ni equivalent exceeds 24 (%), the amount of martensite generated by strain of the steel wire after cold drawing decreases, the strength decreases, and the effect of the present invention is reduced, and therefore, it is determined to be 24 (%) or more. On the other hand, if the value of the Ni equivalent is less than 20 (%), the austenite-hot-treated martensite itself of the steel wire after cold drawing is reduced, and the ductility is lowered, so that the lower limit is set to 20%. In particular, in order to maximize the strength of the austenite-forming heat treatment by the usual cold drawing process, the Ni equivalent is preferably set to 21 (%) to 23 (%).
GI (%) in formula (2) was obtained by examining the influence of each element on the rigidity modulus after cold drawing, and indicates the effective element for the rigidity modulus and the degree of influence.
GI(％)＝16C+2Mn+9Ni-3Cr+8Mo+15N (2)
The value of GI is set to 30 (%) or less, as necessary. When the value of GI exceeds 30 (%), the rigidity modulus after cold drawing is low, and therefore, it is preferably limited to 30 (%). Particularly preferably 25 (%) or less.
The process for producing the steel wire of the present invention is described below in brief.
The steel wire of the present invention can be produced by any of the following processes.
That is, steel adjusted to a desired composition is hot-rolled to form a stainless steel wire rod, and after solution treatment (including continuous treatment after rolling), first, a steel wire (final product) is formed by finish cold drawing, or when the diameter of the final steel wire is greatly different from the diameter of the stainless steel wire rod, the above-mentioned solution treated stainless steel wire rod is repeatedly subjected to cold drawing and annealing (solution treatment) 1 or more times to form a thick wire (wire), and after the thick wire is subjected to a plurality of continuous anneals (solution treatments), finish cold drawing is performed to form a steel wire (final product). In this series of steps, the solution treatment (including the multiple continuous annealing) may be performed in an atmosphere containing hydrogen or in an atmosphere not containing hydrogen, but as will be described later in the present invention, at least the final solution treatment is performed in an atmosphere not containing hydrogen, and finish cold drawing is performed under specific conditions. The term "solution treatment" as used herein means that carbide is brought into a solid solution state.
In the present invention, as one of the above-described series of steps, the dehydrogenation treatment is performed in an atmosphere not containing hydrogen gas, and finish cold drawing is performed under specific conditions.
The conditions for the cold drawing process will be described below.
The formula (3) represents the cold-drawn wire processing amount of the wire rod or the thick wire after the solution treatment, and the formula (4) represents the range thereof.
ε＝ln(A0/A) (3)
Wherein A is0: cross-sectional area of wire rod or thick wire before cold-drawing
A: cross-sectional area of steel wire after cold drawing
0.15X (Ni equivalent) -2.28. ltoreq. epsilon. 0.15X (Ni equivalent) -0.88 (4)
When general cold drawing is performed at room temperature, the value of the cold drawing amount epsilon defined by the formula (3) falls within the range defined by the formula (4). When the range is smaller than the range of formula (4), the tensile strength of the steel wire after cold drawing is lowered, and the modulus of rigidity is also lowered. On the other hand, if the range is larger than the range of the formula (4), the amount of martensite in the steel wire after cold drawing increases, and the ductility decreases. Therefore, the cold-drawing amount after the solution treatment is defined by the formulas (3) and (4).
The conditions of the solution treatment (including multiple continuous annealing) and the dehydrogenation treatment of the wire rod or the thick wire are explained below.
As described above, the ductility and the amount of hydrogen in the steel wire show dependency. When the solution treatment is performed in an atmosphere of a reducing gas containing hydrogen, the steel contains more than 4ppm of hydrogen due to the absorption of hydrogen, and the ductility is deteriorated. Therefore, at least the final solution treatment in the above steps is performed in an atmosphere such as argon, nitrogen, or air, which does not contain hydrogen, so that the hydrogen content in the steel is 4ppm or less. Particularly, it is preferable to carry out the reaction under an atmosphere of argon or the like to prevent surface oxidation.
In order to reduce the amount of hydrogen in the steel to 4ppm or less, as one of the series of steps, for example, dehydrogenation treatment is performed before and after solution treatment of wire rod, before and after solution treatment of cold drawing for forming a rough wire, before and after solution treatment of finish cold drawing, or the like. That is, if the dehydrogenation treatment is performed in an atmosphere containing no hydrogen gas at 200 to 600 ℃, the ductility can be improved. In this case, the effect is not clear at 200 ℃ or below 200 ℃, and when it exceeds 600 ℃, the scale becomes thick and the manufacturability becomes poor. Therefore, the dehydrogenation treatment is preferably carried out at 200 to 600 ℃, more preferably at 200 to 400 ℃ in an atmosphere of argon, nitrogen, air or the like which does not contain hydrogen.
The grain size of the austenite structure before cold drawing of the wire rod or the thick wire is described below.
When the average grain size of the austenite structure of the wire rod or the thick wire before the cold drawing exceeds 30 μm, the ductility of the steel wire after the cold drawing is lowered. Therefore, the solution treatment conditions of the wire rod or the thick wire before the cold drawing are adjusted as necessary, and for example, the wire rod or the thick wire is rapidly cooled from the temperature range of 950 to 1150 ℃ at a cooling rate of 5 ℃/sec or more on average to 500 ℃ or less at 500 ℃ or less so that the average grain size of the austenite structure is 30 μm or less.
Examples
The present invention will be described in further detail below based on examples of the present invention.
The tensile strength of the steel wire after cold drawing is 1700N/mm2Or 1700N/mm2As described above, the number of twists is 10 or more, which is an important factor of ductility of the steel wire for springs, and the modulus of rigidity is 63GPa or more, which is an important factor of the modulus of elasticity of the steel wire for springs. The young's modulus is also an important factor of the elastic modulus, but in the present invention, the stiffness modulus is defined as a representative value thereof.
The test materials of the examples were obtained by melting, hot-rolling to Φ 5.5mm, and finish-rolling at 1000 ℃ in a production process of a usual stainless steel wire rod. The obtained wire rod was subjected to heat treatment (solution treatment) at 1050 ℃ for 5 minutes, and water-cooled. Then, a part of the wire is subjected to dehydrogenation treatment to obtain an intermediate cold-drawn wire. Then, the thick wire was subjected to solution treatment at 1050 ℃ in an argon atmosphere in a multi-strand continuous annealing furnace, and then subjected to finish cold drawing to obtain a steel wire.
Then, the average grain size of austenite of the rough wire before the finish cold-drawing (after solution treatment) and the hydrogen content, the amount of martensite generated by strain, the tensile strength, the number of twists, and the modulus of rigidity of the steel wire after the finish cold-drawing were examined.
The cross section of the thick wire was electrolytically etched in a 10% nitric acid solution, and then the cross-sectional area of each crystal was determined by image analysis, and the average grain size of austenite of the thick wire before cold drawing was expressed as an average value of 10 points of a converted diameter (d) of the area.
A sample was taken from the steel wire after cold drawing and the amount of hydrogen was measured by an inert gas melting-thermal conductivity measuring method.
The saturated magnetization is measured by a direct current type BH tracer, and the amount of martensite generated by strain of the steel wire after finish machining and cold drawing is obtained.
The tensile strength of the steel wire after cold drawing was measured by the tensile test of JIS Z2241.
The number of twists of the steel wire after cold drawing was evaluated by the number of twists from the twist test to the breakage.
The modulus of rigidity of the steel wire after cold drawing was measured by the torsional pendulum method.
First, the effects of the essential ingredients of the present invention will be described. The test material was a steel wire prepared as follows: the wire rod is rolled in a hot state and subjected to solution treatment, then the wire rod is subjected to intermediate cold drawing processing to prepare a thick wire with the diameter of 3.4mm, then the solution treatment is carried out in an argon atmosphere, and then finish cold drawing is carried out until the diameter of 1.6 mm. Table 1 shows the basic components of the examples and the characteristics of the steel wire.
The effects of the matrix components C, Si, Mn, P, S, Ni, Cr, Mo, Cu, O and N on the properties of the steel wires were examined for inventive examples Nos. 1 to 19 and comparative examples Nos. 20 to 32.
The tensile strength of all steel wires of the embodiment of the invention is 1700N/mm2Or 1700N/mm2The number of twists is 10 or more, the modulus of rigidity is 63GPa or more, and the number of twists and the modulus of rigidity are excellent under high strength. In addition, in comparison with No.1 and No.19 of the present invention, the number of twists was increased by decreasing P.
However, in comparative example 20, the amount of C was low, and the number of twists and the elastic modulus were not low, but the strength was low, so that the effect of the present invention was not remarkable.
In comparative example No.21, the amount of C was high and the number of twists was low.
In comparative example 22, the amount of N was high, and the number of twists was low because of occurrence of material defects such as voids.
In comparative example No.23, the amount of Si was high and the number of twists was low.
In comparative example No.24, the Mn content was high and the number of twists was low.
In comparative example No.25, the amount of Ni was high, the amount of strain-induced martensite was low, and the rigidity modulus was poor.
In comparative example No.26, the amount of Ni was low, the amount of strain-induced martensite was high, and the number of twists was low.
In comparative example 27, the amount of Cr was low, the amount of strain-induced martensite was high, and the number of twists was low.
In comparative example No.28, the amount of Cr was high, the number of twists was low, the amount of strain-induced martensite was also low, and the modulus of rigidity was also poor.
In comparative example No.29, Mo was high and the rigidity modulus was poor.
In comparative example 30, since Cu content is high and tensile strength is low, not only the effect of high number of twists of the present invention is not clear, but also martensite content due to strain is low and rigidity modulus is poor.
In comparative examples No.31 and No.32, the O amount and S amount were high, respectively, and the number of twists was low.
Next, the effects of the present invention of grain refinement and the addition of grain refinement elements will be described. The test material was a steel wire prepared as follows: the wire rod is rolled in a hot state and subjected to solution treatment, then the wire rod is subjected to intermediate cold drawing processing to prepare a thick wire with the diameter of 3.4mm, then the solution treatment is carried out in an argon atmosphere, and then finish cold drawing is carried out until the diameter of 1.6 mm. . Table 2 shows the basic components of the examples and the characteristics of the steel wire.
The effects of grain refinement and addition of grain refinement elements on the number of twists of the steel wire were examined for inventive examples 33 to 44 and comparative examples 45 and 46.
In the present invention examples 34 to 44, Al, Nb, Ti, Zr, Ta, W and V were added for grain refinement, and the average grain size was 10 μm, and the number of twists was significantly increased as compared with the present invention example 33. The effect of grain refinement on high twist count is demonstrated. In addition, the tensile strengths of inventive examples Nos. 34 to 44(Ni equivalent: 21.7 to 22.1% in total) in Table 2 were set to 2000N/mm2Or 2000N/mm2The above-mentioned numbers of twists (29 times, 25 times, 32 times, and 25 times, respectively) of Nos. 35, 36, 38, and 44 were 21.7 to 22.1% in Ni equivalent and 2000N/mm in tensile strength, as compared with the present invention examples Nos. 1 to 19 in which no grain refining element was added, as shown in Table 12Or 2000N/mm2The effect of adding the grain refining element is clearly seen in comparison of the numbers of twists (13 times, 11 times, and 13 times, respectively) of nos. 3, 11, 12, and 18.
However, in comparative examples No.45 and No.46, Al or Nb was excessively added, and therefore the number of twists was rather reduced.
The effect of the present invention for reducing the amount of hydrogen and the effect of the production method for reducing the amount of hydrogen will be described below. Table 3 shows the manufacturing conditions and characteristics of the examples. The test material was prepared by subjecting steel type a of table 1 to hot-rolling and solution treatment, and then subjecting a part of the wire rod to dehydrogenation treatment under the conditions shown in table 3. Then, intermediate cold drawing was performed until Φ 3.4mm to obtain a thick wire, and then, a plurality of continuous anneals (solution treatments) were performed under the atmosphere gas conditions shown in table 3, and then, the thick wire was subjected to finish cold drawing to obtain a steel wire having Φ 1.6 mm.
Examples 47 to 55 of the present invention and comparative examples 56 and 57 are examples of investigating the effect of grain refinement and the addition of grain refinement elements on the number of twists imparted to steel wire.
In the invention examples No.47 to No.55, the number of twists was high because the amount of hydrogen was low. In particular, in the case of examples 50 to 55 of the present invention, the hydrogen amount was further reduced by the dehydrogenation treatment, and the number of twists was further increased. This demonstrates the effect of high twist times produced by the reduction of hydrogen.
In addition, comparative examples 56 and 57 were annealed in an atmosphere containing hydrogen gas, and the number of twists was low because the amount of hydrogen in the material was high.
The effect of the cold-drawing method of the present invention will be described below. Table 4 shows the cold drawing conditions and characteristics of the examples, and the materials for the tests were produced by subjecting the steel type AH of table 2, the steel type I of table 1, and the steel type L to hot rolling, solution treatment, intermediate cold drawing until Φ 3.4mm was performed on the wire rod to produce a thick wire, then, multiple continuous annealing (solution treatment) was performed in an argon atmosphere, and then, finish cold drawing was performed on the thick wire at the cold drawing amount of table 4 to produce a steel wire. Table 4 also shows the ranges of the optimum cold-drawn wire processing amounts calculated from expressions (3) and (4).
Examples 58 to 66 of the present invention and comparative examples 67 to 72 were examples for investigating the effect of the cold drawing amount on the tensile strength, the number of twists, and the modulus of rigidity of the steel wire.
The inventive examples 58 to 66 had high tensile strength and exhibited high number of twists and high modulus of rigidity because of appropriate cold-drawn wire processing amount.
However, comparative examples 67, 69 and 71 had low tensile strength due to low cold drawing amount, and not only the effect of high number of twists of the present invention was not clear, but also the amount of strain-induced martensite was low and the modulus of rigidity was poor.
In comparative examples 68, 70 and 72, the amount of cold drawing was too high, the amount of martensite generated by strain was large, and the number of twists was low.
As is clear from the above examples, the high strength stainless steel wire of the present invention is excellent in the number of twists (ductility) and the modulus of rigidity.
TABLE 1
No. Steel grade Chemical composition (% by mass) 2C+N(％) Ni equivalent (%) GI(％) Amount of hydrogen (ppm) Average grain size (. mu.m) Amount of Strain-induced martensite (% by volume) Tensile strength (N/mm)2) Number of twists (times) Modulus of rigidity (GPa)
C Si Mn P S Ni Cr Mo Cu O N
Examples of the invention 1 A 0.1 0.8 1.6 0.03 0.0033 7 17 0.1 0.2 0.005 0.06 0.26 22.0 18.5 2.2 40 51 1990 17 67
2 B 0.04 0.8 1.5 0.02 0.0045 7 16.9 0.1 0.1 0.006 0.1 0.18 21.6 18.2 2 30 70 1910 14 68
3 C 0.13 0.8 1.5 0.04 0.0052 7 17.1 0.2 0.1 0.004 0.02 0.28 22.0 18.7 1.8 30 58 2050 13 69
4 D 0.03 0.8 1.5 0.03 0.0023 6.9 17 0.1 0.2 0.004 0.17 0.23 22.4 17.9 2.3 40 31 1850 40 66
5 E 0.1 0.2 1.6 0.03 0.0008 7 17.1 0.3 0.2 0.005 0.06 0.26 22.1 19.8 3 50 51 1990 32 66
6 F 0.1 2 1.5 0.02 0.0038 7 17 0.1 0.1 0.005 0.06 0.26 22.4 18.3 2.8 30 41 1950 35 66
7 G 0.1 3.5 1.5 0.03 0.0003 6.9 16.9 0.1 0.2 0.002 0.06 0.26 22.7 17.7 2.1 40 24 1880 40 65
8 H 0.08 0.8 0.3 0.03 0.0020 8.5 17 0.1 0.2 0.006 0.05 0.21 21.9 28.9 1.8 30 25 1790 43 63
9 I 0.1 0.7 3 0.02 0.0063 7 17 0.2 0.1 0.005 0.06 0.26 23.5 22.1 1.5 40 38 1940 36 65
10 J 0.11 0.8 4.5 0.03 0.0072 5.6 17 0.1 0.2 0.003 0.07 0.29 23.8 12.0 1.8 50 61 2080 12 69
11 K 0.1 0.8 0.5 0.03 0.0023 6.8 17.2 0.1 0.2 0.005 0.06 0.26 20.9 13.9 2.3 30 67 2050 13 70
12 L 0.11 0.8 1.6 0.04 0.0046 7.3 14.5 0.1 0.3 0.005 0.06 0.28 20.8 28.9 3.1 40 75 2120 11 67
13 M 0.09 0.8 1.3 0.03 0.0028 7.2 18.5 0.1 0.2 0.005 0.05 0.23 22.7 14.9 3.2 50 31 1850 25 65
14 N 0.09 0.8 1.4 0.04 0.0015 7.2 17 0.8 0.2 0.004 0.06 0.24 22.6 25.3 1.8 40 34 1880 38 65
15 O 0.08 0.8 1.3 0.03 0.0064 7 17.1 1.7 0.1 0.005 0.04 0.23 23.4 29.8 2.5 40 23 1820 46 64
16 P 0.07 0.8 1.3 0.03 0.0039 6.8 17.6 2.1 0.05 0.003 0.04 0.18 23.3 29.5 2.1 30 22 1820 40 63
17 Q 0.09 0.7 1.6 0.03 0.0088 7 17.1 0.1 0.2 0.003 0.06 0.24 22.0 18.0 2.7 50 56 1970 18 67
18 R 0.1 0.6 1.6 0.03 0.0012 6.9 17 0.1 0.2 0.009 0.05 0.25 21.8 17.5 2.2 40 63 2020 13 67
19 R 0.09 0.6 1.6 0.01 0.0007 7.1 17.1 0.1 0.2 0.009 0.06 0.24 22.0 18.9 2.2 40 54 1960 30 67
Comparative example 20 S 0.02* 0.8 1.6 0.03 0.003 7.2 17.1 0.1 0.2 0.005 0.06 0.1* 21.3 18.7 2.8 30 90* 1650 18 65
21 T 0.15* 0.6 1.6 0.03 0.003 6.9 17 0.1 0.1 0.005 0.04 0.34* 22.3 18.1 2.1 30 42 2100 2* 67
22 U 0.04 0.8 1.6 0.03 0.003 6.9 17 0.1 0.1 0.005 0.22* 0.3 23.2 19.0 1.9 40 0* 1850 3* 63
23 V 0.1 4.5* 1.4 0.03 0.003 6.8 16.8 0.1 0.2 0.005 0.05 0.25 22.7 16.8 2 40 25 1870 7* 65
24 W 0.08 0.8 6* 0.03 0.003 6.5 17.1 0.1 0.2 0.005 0.05 0.21 25.6 22.0 1.8 30 40 1850 8* 63
25 X 0.09 0.7 0.6 0.03 0.003 9.5* 17 0.1 0.2 0.005 0.05 0.23 23.3 38.7* 1.7 50 0* 1700 55 60*
26 Y 0.1 0.8 3.8 0.03 0.003 4.5* 17 0.1 0.2 0.005 0.05 0.25 21.6 0.3 2.2 40 95* 2280 1* 70
27 Z 0.09 0.7 1.5 0.03 0.003 7.2 13.8* 0.1 0.2 0.005 0.05 0.23 19.8* 29.4 2.3 30 95* 2180 2* 66
28 AA 0.09 0.8 1.4 0.03 0.003 7 19.6* 0.1 0.2 0.005 0.05 0.23 23.3 10.0 2.2 30 15* 1800 8* 62*
29 AB 0.08 0.7 1.3 0.03 0.003 6.8 16.8 3.5* 0.2 0.005 0.05 0.21 24.4* 43.4* 2.4 50 3* 1720 15 59*
30 AC 0.1 0.7 1.6 0.03 0.003 7.1 17 0.1 1.5* 0.005 0.06 0.26 22.1 19.4 2.5 40 1* 1660* 40 60*
31 AD 0.1 0.8 1.6 0.03 0.0082 6.9 17 0.1 0.2 0.014* 0.05 0.25 21.8 17.5 3.1 40 62 2010 5* 67
32 AE 0.09 0.6 1.6 0.03 0.015* 6.9 17 0.1 0.2 0.07 0.06 0.24 21.8 17.4 1.9 30 64 2000 7* 67
*: outside the present invention.
TABLE 2
No. Steel grade Chemical composition (% by mass) 2C+N(％) Ni equivalent (%) GI(％) Amount of hydrogen (ppm) Average grain size (. mu.m) Amount of Strain-induced martensite (% by volume) Tensile strength (N/mm)2) Number of twists (times) Modulus of rigidity (GPa)
C Si Mn P S Ni Cr Mo Cu O N (others)
Examples of the invention 33 AF 0.1 0.7 1.7 0.03 0.0033 6.9 17 0.1 0.2 0.005 0.06 0.26 22.0 17.8 3.1 50 55.0 2000 18 67
34 AG 0.09 0.8 1.6 0.02 0.0043 7.1 16.9 0.2 0.1 0.002 0.05 Al；0.02 0.23 21.9 20.2 2.1 10 63.0 1980 34 67
35 AH 0.11 0.6 1.5 0.03 0.0008 7.1 17.1 0.3 0.1 0.004 0.04 Al；0.06 0.26 22.1 20.4 2.5 10 54.0 2000 29 68
36 AI 0.1 0.8 1.4 0.02 0.0029 7 17 0.1 0.2 0.002 0.06 Al；0.18 0.26 21.8 18.1 1.9 10 53.0 2000 25 68
37 AJ 0.1 0.8 1.4 0.02 0.0029 7 17 0.1 0.2 0.005 0.06 Nb；0.08 0.26 21.8 18.1 2.2 20 52.0 1990 31 67
38 AK 0.09 0.7 1.5 0.03 0.0035 6.9 17.1 0.2 0.1 0.006 0.05 Nb；0.25 0.23 21.7 17.6 3 10 70.0 2000 32 68
39 AL 0.1 0.8 1.6 0.03 0.0044 7 17 0.3 0.1 0.003 0.05 Ti；0.07 0.25 22.1 20.0 1.8 10 56.0 1980 24 67
40 AM 0.09 0.8 1.5 0.02 0.0008 7.2 17 0.2 0.1 0.003 0.05 Zr；0.22 0. 23 22.0 20.6 2.2 l0 58.0 1950 25 66
4l AN 0.09 0.8 1.5 0.02 0.0008 7.2 17 0.2 0.1 0.003 0.05 Ta；0.15 0.23 22.0 20.6 2.2 10 60.0 1950 23 67
42 AO 0.1 0.7 1.6 0.03 0.0016 7.1 16.9 0.1 0.2 0.004 0.06 W；0.17 0.26 22.0 19.7 2.2 20 50.0 1980 24 66
43 AP 0.09 0.8 1.5 0.02 0.0021 7 17 0.1 0.2 0.004 0.05 Al；0.03，Nb；0.1 0.23 21.7 18.0 2.2 10 54.0 1980 33 68
44 AO 0.1 0.7 1.5 0.02 0.0034 7.1 17.1 0.1 0.1 0.005 0.05 V；0.3 0.25 22.0 18.8 2.2 10 58.0 2010 25 87
Comparison 45 AR 0.09 0.7 1.6 0.03 0.0005 7.1 17.1 0.1 0.1 0.002 0.06 Al；0.38* 0.24 22.1 18.9 2.2 10 57.0 1970 5 57
46 AS 0.1 0.8 1.5 0.03 0.0011 7.1 17.1 0.1 0.1 0.005 0.06 Nb；0.50* 0.26 22.1 18.9 2.2 10 50.0 2000 6 66
*: outside the present invention.
TABLE 3
No. Steel grade Dehydrogenation treatment Gas of continuous annealing atmosphere Amount of hydrogen (ppm) Average grain size (. mu.m) Amount of martensite produced by Strain (% by volume) Tensile strength (N/mm)2) Number of twists (times) Modulus of rigidity (GPa)
Examples of the invention 47 A Untreated Argon gas 2.2 10 60 2000 17 67
48 A Untreated Nitrogen gas 2.5 10 63 1980 17 67
49 A Untreated Atmosphere (es) 2.1 10 61 2050 16 68
50 A 300-24 h, atmosphere Argon gas 0.8 10 58 2040 22 67
51 A 300-24 h of nitrogen Argon gas 0.9 10 62 2030 21 68
52 A 250-24 h, atmosphere Argon gas 1.2 10 63 2000 20 67
53 A 150-24 h, atmosphere Argon gas 2 10 65 1990 18 67
54 A 450-24 h, atmosphere Argon gas 0.7 10 59 2020 25 68
55 A 550-24 h, atmosphere Argon gas 1.1 10 60 2030 22 68
Comparison 56 A Untreated Hydrogen-containing gas 6.3* 10 61 2050 7* 66
57 A 300-24 h, atmosphere Hydrogen-containing gas 5.3* 10 62 2100 5* 65
*: outside the present invention.
TABLE 4
No. Steel grade Ni equivalent (%) Optimum range of cold-drawn wire working amount, epsilon Actual cold-drawn wire processing amount; epsilon Amount of hydrogen (ppm) Average grain size (. mu.m) Amount of martensite produced by Strain (% by volume) Tensile strength (N/mm)2) Number of twists (times) Modulus of rigidity (GPa)
Examples of the invention 58 AH 22.1 1.035～2.435 1.51 2.4 10 55 2000 29 68
59 AH 22.1 1.035～2.435 1.1 6 2.3 10 30 1860 43 65
60 AH 22.1 1.035～2.435 2.08 2.1 10 75 2210 12 68
61 I 23.5 1.245～2.645 1.51 1.8 40 40 1950 34 65
62 I 23.5 1.245～2.645 1.27 2 40 25 1820 48 64
63 I 23.5 1.245～2.645 2.45 2.1 40 76 2080 20 66
64 L 20.8 0.84～2.24 1.51 2.8 30 70 2100 12 67
65 L 20.8 0.84～2.24 0.87 2.5 30 30 1830 19 64
66 L 20.8 0.84～2.24 2.00 2.4 30 78 2200 10 68
Comparative example 67 AH 22.1 1.035～2.435 0.96* 2.5 10 18* 1650 45 62*
68 AH 22.1 1.035～2.435 2.45* 2.3 10 83* 2200 5* 68
69 I 23.5 1.245～2.645 1.06* 1.9 40 10* 1640 50 62*
70 I 23.5 1.245～2.645 2.89* 2.3 40 84* 2240 5* 66
71 L 20.8 0.84～2.24 0.78* 2.8 30 18* 1680 23 62*
72 L 20.8 0.84～2.24 2.45* 3 30 90* 2240 2* 68
*: outside the scope of the invention.
According to the high-strength stainless steel wire excellent in ductility and modulus of rigidity and the method for producing the same of the present invention, the basic components and purity (oxygen, sulfur) of the matrix metal of the austenitic stainless steel wire are specified, and the structure, strength, and cold drawing conditions are defined, and the effect of strengthening and toughening by grain refinement and austenite shape heat treatment is used, whereby the high-strength stainless steel wire remarkably improved in ductility and modulus of rigidity can be stably obtained.

Claims (4)

1. A high-strength stainless steel wire having excellent number of twists and excellent rigidity modulus, characterized by containing, in mass%, C: 0.03 to 0.14%, Si: 0.1-4.0%, Mn: 0.1 to 5.0%, Ni: 5.0-9.0%, Cr: 14.0 to 19.0%, N: 0.005-0.20%, O: 0.001-0.01%, S: 0.0001 to 0.012%, further contains any one of (i) and (ii) 1 or more, and if necessary (iii), and the balance is Fe and inevitable impurities, and 2C + N is 0.17 to 0.32%, the value of Ni equivalent% of the following formula (1) is 20 to 24, H is not more than 4ppm, the value of GI% of the following formula (2) is 30 or less,
(i) the method comprises the following steps Any 1 or more than 1 of Al, Nb, Ti, Zr, Ta and W, which are respectively 0.01-0.30%;
(ii) the method comprises the following steps V is 0.1-0.5%;
(iii) the method comprises the following steps Mo is 0.2-3.0%;
ni equivalent% (% Ni +0.65Cr +0.98Mo +1.06Mn +0.35Si +12.6(C + N) (1)
GI％＝16C+2Mn+9Ni-3Cr+8Mo+15N (2)。
2. A method for producing a high-strength stainless steel wire having excellent torsional modulus and rigidity modulus, characterized by comprising the steps of mixing, by mass%, C: 0.03 to 0.14%, Si: 0.1-4.0%, Mn: 0.1 to 5.0%, Ni: 5.0-9.0%, Cr: 14.0 to 19.0%, N: 0.005-0.20%, O: 0.001-0.01%, S: 0.0001 to 0.012%, further contains any one of (i) and (ii), and if necessary contains (iii), and the balance is composed of Fe and unavoidable impurities, and the 2C + N is 0.17 to 0.32%, the value of Ni equivalent% of the following formula (1) is 20 to 24, the value of GI% of the following formula (2) is 30 or less, after hot rolling and solution treatment, or after subjecting the wire rod to solution treatment and cold drawing for 1 or more times to form a rough wire, in a series of steps of finish cold drawing to form a steel wire, at least the last solution treatment is performed in an atmosphere not containing hydrogen gas so that H in the steel is 4ppm or less, finish cold drawing is performed so that a cold drawing amount ε represented by the formula (3) is within the range of the formula (4),
(i) the method comprises the following steps Any 1 or more than 1 of Al, Nb, Ti, Zr, Ta and W, which are respectively 0.01-0.30%;
(ii) the method comprises the following steps V is 0.1-0.5%;
(iii) the method comprises the following steps Mo is 0.2-3.0%;
ni equivalent% (% Ni +0.65Cr +0.98Mo +1.06Mn +0.35Si +12.6(C + N) (1)
GI％＝16C+2Mn+9Ni-3Cr+8Mo+15N (2)
ε＝ln(A0/A) (3)
Wherein A is0: cross-sectional area of wire rod or thick wire before cold-drawing
A: cross-sectional area of steel wire after cold drawing
0.15 × (Ni equivalent) -2.28 ≦ ε ≦ 0.15 × (Ni equivalent) -0.88 (4).
3. The method of producing a high-strength stainless steel wire excellent in the number of twists and the rigidity modulus as set forth in claim 2, wherein the series of steps includes a step of adding a solution treatment prior to the solution treatment in an atmosphere not containing hydrogen gas, and in the step of adding, the dehydrogenation treatment is performed in an atmosphere not containing hydrogen gas and having a temperature of 200 ℃ to 600 ℃.
4. A method of manufacturing a high strength stainless steel wire excellent in the number of twists and the rigidity modulus according to claim 2 or 3, wherein the austenite average grain size before cold drawing of the wire rod or the thick wire is 30 μm or less.
HK05101661.1A 2002-05-08 High strength stainless steel wire excellent in frequency of torque and modulus of rigidity and method for production thereof HK1069190B (en)

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