WO2015005311A1 - コイルばね、およびその製造方法 - Google Patents

コイルばね、およびその製造方法 Download PDF

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Publication number
WO2015005311A1
WO2015005311A1 PCT/JP2014/068123 JP2014068123W WO2015005311A1 WO 2015005311 A1 WO2015005311 A1 WO 2015005311A1 JP 2014068123 W JP2014068123 W JP 2014068123W WO 2015005311 A1 WO2015005311 A1 WO 2015005311A1
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Prior art keywords
coil spring
less
fatigue resistance
depth
grain size
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PCT/JP2014/068123
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English (en)
French (fr)
Japanese (ja)
Inventor
文男 山本
健吾 鶴貝
吉原　直
慶 増本
宏之 大浦
鉄男 神保
前畑　俊男
山本　賢治
Original Assignee
日本発條株式会社
株式会社神戸製鋼所
神鋼鋼線工業株式会社
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Application filed by 日本発條株式会社, 株式会社神戸製鋼所, 神鋼鋼線工業株式会社 filed Critical 日本発條株式会社
Priority to CN201480039266.5A priority Critical patent/CN105358726B/zh
Priority to KR1020167000388A priority patent/KR101789944B1/ko
Priority to EP14823237.4A priority patent/EP3020841B1/en
Priority to US14/903,975 priority patent/US20160160306A1/en
Publication of WO2015005311A1 publication Critical patent/WO2015005311A1/ja

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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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/773—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material under reduced pressure or vacuum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • 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
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/46—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
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising
    • C23C8/22—Carburising of ferrous surfaces

Definitions

  • the present invention relates to a coil spring and a manufacturing method thereof, and more particularly to a coil spring excellent in fatigue resistance and a manufacturing method thereof.
  • Coil springs are used as valve springs, clutch springs, suspension springs, etc. in automobile engines, clutches, suspensions, etc. Since the coil spring is repeatedly used with a high stress over a long period of time, a high level of fatigue resistance is required.
  • JIS includes an oil temper wire for a valve spring (SWO-V: JIS G 3561), a chrome vanadium steel oil temper wire for a valve spring (SWOCV-V: JIS G 3565), and Silicon chrome steel oil tempered wire (SWOSC-V: JIS G 3566) for valve springs has been defined, and conventionally, SWOSC-V having excellent fatigue strength has been mainly used.
  • wire rods are subjected to quenching and tempering treatment after drawing the rolled material, and are made to have the required strength, and after using this, coiling into a spring of the required shape, nitriding, shot peening, temper,
  • a general manufacturing method of a valve spring is to obtain a spring having excellent fatigue resistance by performing a treatment such as setting.
  • valve spring As for the valve spring, it is possible to make the valve spring more compact by further improving its fatigue resistance, and to contribute to the weight reduction of the engine. Therefore, proposals have been made to improve the fatigue resistance of valve springs.
  • Patent Document 1 has a predetermined composition, has a carburized hardened layer (0.05 to 1.00 mm) on the surface, and has a hardness at a position of 0.02 mm from the surface within a predetermined range ( 650-1000 Hv), a technique for improving fatigue resistance is disclosed.
  • the present invention has been made paying attention to the above circumstances, and an object thereof is to provide a coil spring excellent in fatigue resistance and a method of manufacturing such a coil spring excellent in fatigue resistance. There is.
  • the present invention that has solved the above problems includes C: 0.40 to 0.70% (% means “mass%”, the same applies to the chemical composition), Si: 1.50 to 3.50% , Mn: 0.30 to 1.50%, Cr: 0.10 to 1.50%, V: 0.50 to 1.00%, Al: 0.01% or less (excluding 0%)
  • the balance is made of iron and steel, which is an inevitable impurity, and the average grain size number of the prior austenite crystals at a depth of 0.3 mm from the surface layer is 11.0 or more, and the grain size number difference of the prior austenite crystals is It has a carburized hardened layer with a depth of 0.30 to 1.00 mm from the surface layer and a depth direction (1/4) ⁇ diameter from the surface layer within a range of less than 3 compared to the maximum frequency particle size number. It is necessary that the average value of Vickers hardness at the position is 600 or more. Having.
  • the chemical component composition of the coil spring includes Ni: 1.50% or less (not including 0%) and / or Nb: 0.50% or less (not including 0%). .
  • the vacuum carburizing treatment be performed at 1000 ° C. or higher.
  • the chemical composition and the prior austenite grain size are appropriately controlled, and the depth of the carburized hardened layer from the coil spring surface layer and the Vickers hardness are appropriately controlled, thereby improving fatigue resistance.
  • An excellent coil spring can be provided.
  • a coil spring having excellent fatigue resistance can be provided.
  • FIG. 1 is a schematic explanatory view of a carburized hardened layer measurement position of a coil spring and a Vickers hardness measurement position of a 1/4 ⁇ diameter position.
  • FIG. 2 is a schematic explanatory view of the measurement position of the prior austenite grain size of the coil spring.
  • the fatigue resistance of the present invention is further improved than before, and results in exceeding 60 million times in the fracture life test in the examples described below.
  • Patent Document 1 while increasing the amount of C added and controlling the metallographic structure, it was not possible to obtain a fracture life of 60 million times (Example 4 of Patent Document 1 and the Example). No. 8 in Table 2 that simulates the above.
  • the present inventors have found that the toughness and strength of the coil spring have an effect on fatigue breakage during use of the coil spring. We obtained knowledge that fatigue resistance can be greatly improved by appropriately controlling these.
  • the depth of the carburized hardened layer from the steel surface layer (hereinafter simply referred to as “surface layer”) forming the coil spring and the inside of the steel (1/4 ⁇ coil spring) It is necessary to sufficiently secure the Vickers hardness of the steel wire forming the diameter D, which may be hereinafter referred to as “1/4 ⁇ D”.
  • the temperature during the carburizing process In order to sufficiently secure the depth of the carburized hardened layer and the Vickers hardness, it is necessary to increase the temperature during the carburizing process. However, the fracture life cannot be improved only by carburizing at a high temperature.
  • the balance between strength and toughness required for improving fatigue resistance is further achieved by appropriately controlling the carburized layer depth, Vickers hardness, and prior austenite grain size.
  • the present inventors have found that a coil spring having excellent fatigue resistance can be provided.
  • C 0.40 to 0.70%
  • C is an element useful for ensuring the strength of a coil spring to which a high stress is applied and the Vickers hardness at the 1/4 ⁇ D position of the coil spring.
  • the C content is 0.40% or more, preferably 0.45% or more, more preferably 0.50% or more.
  • the C content is 0.70% or less, preferably 0.65% or less, more preferably 0.60% or less.
  • Si 1.50 to 3.50% Si, like C, is an element useful for ensuring Vickers hardness, and is an element effective for improving the strength of the coil spring and improving fatigue resistance and sag resistance.
  • the Si content is 1.50% or more, preferably 1.80% or more, more preferably 2.10% or more.
  • the Si content is 3.50% or less, preferably 3.30% or less, more preferably 3.10% or less.
  • Mn 0.30 to 1.50%
  • Mn is an element effective for enhancing the hardenability and improving the strength of the coil spring. Moreover, it has the effect
  • the Mn content is 0.30% or more, preferably 0.40% or more, more preferably 0.50% or more.
  • the Mn content is 1.50% or less, preferably 1.20% or less, more preferably 0.90% or less.
  • Cr 0.10 to 1.50% Cr, like Mn, is an element effective for improving the hardenability and improving the strength of the coil spring. Cr also has the effect of reducing the activity of C and preventing decarburization during hot rolling or heat treatment. In order to exhibit such an effect, the Cr content is 0.10% or more, preferably 0.15% or more, more preferably 0.20% or more. However, when the Cr content is excessive, the C diffusion coefficient in the vacuum carburizing process is remarkably lowered, so that it becomes difficult to form a desired carburized hardened layer and the fatigue resistance is lowered.
  • the Cr content is 1.50% or less, preferably 1.20% or less, more preferably 0.90% or less.
  • V 0.50 to 1.00%
  • V is an element effective for refining the prior austenite crystal grains.
  • V is an element effective for suppressing coarsening of old austenite crystals and generation of mixed grains, which are problematic when the carburizing temperature is increased to secure a desired carburized hardened layer.
  • the V content is 0.50% or more, preferably 0.53% or more, more preferably 0.56% or more.
  • the V content is 1.00% or less, preferably 0.90% or less, more preferably 0.80% or less.
  • Al 0.01% or less (excluding 0%) Al is a deoxidizing element, but when it is contained in excess, inclusions such as AlN are formed. These inclusions significantly reduce the fatigue resistance of the coil spring. Therefore, the Al content needs to be reduced to 0.01% or less, preferably 0.008% or less, more preferably 0.006% or less.
  • the basic chemical composition of steel constituting the coil spring of the present invention is as described above, and the remaining component is substantially iron.
  • “substantially” does not impair the features of the present invention by mixing trace elements that are inevitably mixed in steel raw materials including scrap, iron making / steel making processes, and further steelmaking pretreatment processes. It means to allow in the range.
  • P preferably 0.016% or less, more preferably 0.015% or less
  • S (0.015% or less
  • both Ni and Nb or one of them may be contained within the following range as required.
  • the characteristics of the coil spring are further improved.
  • Ni 1.50% or less (excluding 0%)
  • Ni is an element effective for improving the toughness of the coil spring whose strength is increased by C.
  • the Ni content is preferably 0.05% or more, more preferably 0.10% or more.
  • the Ni content is preferably 1.50% or less, more preferably 1.20% or less, and still more preferably 0.90% or less.
  • Nb 0.50% or less (excluding 0%)
  • Nb has an effect of refining crystal grains in hot rolling and quenching and tempering treatments, and is an element effective for improving ductility.
  • the Nb content is preferably 0.01% or more, more preferably 0.02% or more.
  • the Nb content is preferably 0.50% or less, more preferably 0.40% or less, and still more preferably 0.30% or less.
  • Average grain size number of prior austenite crystals 11.0 or more Fatigue resistance is greatly improved by refining the grain size number of prior austenite crystals at a depth of 0.3 mm from the surface layer of the coil spring and improving toughness. it can.
  • the average grain size number of the prior austenite crystal is 11.0 or more, preferably 12.0 or more, more preferably 13.0 or more.
  • the upper limit of the average grain size number of the prior austenite crystal is not particularly limited. However, in consideration of manufacturability and alloy cost, it is preferably approximately 15.0 or less, more preferably 14.0 or less. is there.
  • the measured grain size number of each prior austenite crystal needs to be further different from the maximum frequency grain size number by less than 3, preferably 2 or less, more preferably 1 or less.
  • no mixed particles a case where the condition of such a particle number difference is satisfied.
  • fatigue resistance can be improved by satisfying the average grain size number of the austenite grains and further suppressing mixed grains.
  • Carburized hardened layer 0.30 to 1.00mm deep from the surface of the coil spring
  • a suitable carburized hardened layer is effective in improving fatigue resistance. That is, by sufficiently curing the surface side of the coil spring, it is possible to suppress the occurrence of breakage starting from the spring surface when it is repeatedly used with a high load stress. In order to exert such an effect, it is necessary to form a carburized hardened layer having a depth of 0.30 mm or more, preferably 0.40 mm or more, more preferably 0.50 mm or more from the surface layer of the coil spring. However, when the carburized hardened layer becomes excessive, the carbide precipitates coarsely, so that the fatigue resistance deteriorates. Therefore, the carburized hardened layer needs to have a depth of 1.00 mm or less, preferably 0.90 mm or less, more preferably 0.80 mm or less from the surface layer of the coil spring.
  • Average value of Vickers hardness at position of depth direction (1/4) ⁇ diameter D from the surface layer 600 or more Appropriate Vickers hardness (Hv) inside the steel of the coil spring is effective in improving fatigue resistance.
  • Hv Vickers hardness
  • the average value of Vickers hardness at least in the depth direction (1/4) ⁇ D position from the surface layer of the coil spring is 600 or more, preferably 670 or more, more preferably 690 or more. is there.
  • the upper limit of the average value of Vickers hardness is not particularly limited, but if it becomes too hard, the toughness may decrease and the fatigue resistance may decrease, so the average value of the Vickers hardness is preferably 750 or less, more preferably Is 730 or less.
  • the coil spring of the present invention is made of steel satisfying the above-mentioned predetermined chemical composition, melted, hot forged, hot rolled to obtain a wire with a desired wire diameter, and is used for cutting, patenting, wire drawing, and oil tempering. Thereafter, it can be manufactured by forming it into a spring and subjecting it to a vacuum carburizing treatment. Thereafter, in order to further improve the fatigue characteristics, shot peening or setting may be performed as necessary.
  • the above melting, hot forging, and hot rolling conditions are not particularly limited, and general production conditions may be employed.
  • a steel ingot that satisfies the above-mentioned predetermined chemical composition is melted in a blast furnace, and then the ingot is rolled into a predetermined size to produce a billet of a predetermined size, which suppresses deformation resistance that affects workability and prior austenite crystals
  • hot rolling may be performed at a desired reduction rate to obtain a desired linear wire.
  • the deoxidized layer on the surface of the wire rod is removed by skinning at a desired thickness, and the work hardened layer produced by the skinning treatment is removed and in order to obtain a structure excellent in wire drawing (for example, pearlite) Performs patenting treatment and softening annealing treatment in IH (high frequency heating) equipment.
  • IH high frequency heating
  • vacuum carburizing treatment is performed.
  • a high temperature carburizing temperature 1000 ° C. or higher.
  • a preferable carburizing temperature is 1020 ° C. or higher, more preferably 1040 ° C. or higher.
  • the carburizing temperature is preferably 1100 ° C. or lower, more preferably 1080 ° C. or lower.
  • a uniform carburized hardened layer can be formed with the said desired thickness by performing a vacuum carburizing process at the temperature of 1000 degreeC or more.
  • the carburizing time and the diffusion time are not particularly limited, and may be such that the desired carburized hardened layer is formed.
  • the carburizing time is 1 to 10 minutes
  • the diffusion time is 1 to 10 minutes.
  • the obtained coil spring may be subjected to general shot peening or setting as necessary for the purpose of further improving fatigue resistance.
  • the coil spring thus obtained can be used as a coil spring having excellent fatigue resistance in various uses such as an engine valve spring and a transmission spring as described above.
  • a steel material was melted in a vacuum melting furnace so as to become steels A to H having chemical compositions shown in Table 1 below (the balance was iron and inevitable impurities), and hot forged to produce a 155 mm square billet.
  • the billet was heated to 1000 ° C. and hot-rolled to produce a spring wire having a diameter of 8.0 mm.
  • the spring wire was soft annealed (held at 660 ° C. for 2 hours), and then the surface layer portion 0.15 mm of the spring wire was shaved to remove the decarburized layer. Thereafter, the spring wire was heated to a temperature of 900 ° C. or higher in a neutral gas atmosphere to be once austenite.
  • lead patenting treatment (heating temperature: 980 ° C., lead furnace temperature: 620 ° C.) was performed on the wire for spring to transform the structure into pearlite.
  • the wire for spring is cold-drawn to a wire diameter of 4.1 mm and treated with oil tempering under conditions suitable for each wire component (heating temperature: 900 ° C. to 1000 ° C., quenching oil temperature: 60 ° C., tempering) (Temperature: 400 to 500 ° C.) to produce a spring wire.
  • a cold spring was formed (coil average diameter 24.60 mm, free height 46.55 mm, effective number of turns 5.75) to obtain a spring.
  • the depth of the carburized hardened layer was specified by measuring the carbon concentration of the coil spring. Specifically, as shown in FIG. 1, four lines are drawn at 90 ° intervals from the center point of the cross section of the steel wire forming the coil spring, and carbon (C)% concentration added on each line (C ) A depth equivalent to% was measured. The measured value was entered in the “depth of carburized hardened layer” column in the table. In the present invention, the case where the depth of the carburized hardened layer is in the range of 0.30 mm to 1.00 mm is regarded as acceptable.
  • the hardness (Hv) of the coil spring was measured using a Vickers hardness tester. Specifically, as shown in FIG. 1, measurement is performed on four lines obtained by subtracting the position (d / 4) of 1 ⁇ 4 ⁇ diameter D of the cross section of the steel wire forming the coil spring at intervals of 90 degrees ( The test load was 10 kgf), and the average value was obtained. The average value was described in the “Vickers hardness” column in the table. In the present invention, a Vickers hardness of 600 or more was considered acceptable.
  • the measuring method of the crystal grain size of the prior austenite crystal of the coil spring is as follows. Specifically, first, as shown in FIG. 2, a section divided into eight equal parts at intervals of 45 degrees from the center point of the cross section of the coil spring is determined. In each section, the grain size of the prior austenite crystal at a depth of 0.3 mm from the surface layer of the steel wire forming the coil spring toward the center is observed with an optical microscope (400 times magnification) based on JIS G 0551. (Size per field of view: 250 ⁇ m ⁇ 200 ⁇ m) was performed and measured. The average measured value was described in the column “average grain size number of old ⁇ crystal” in the table. In the present invention, the average grain size number of the prior austenite crystals is 11.0 or more.
  • the method for judging the difference in the grain size numbers of the prior austenite crystals of the coil spring is as follows. Regarding the crystal grain size number of each of the prior austenite crystals measured above, the case where there was a crystal grain having a difference of 3 or more from the maximum frequency grain size number was judged to be mixed. In the “mixed grain” column of the table, “Yes” is described when mixed grains are present, and “None” is described when mixed grains are not present.
  • Examples 1 to 7 are examples that satisfy the requirements defined in the present invention (chemical component composition, crystal grain size, carburized hardened layer depth, Vickers hardness). No. It can be seen that the coil springs 1 to 7 all have a long fracture life under high load stress (A judgment) and are excellent in fatigue resistance.
  • No. Nos. 8 to 13 did not satisfy the chemical component composition and preferred production conditions specified in the present invention, so that the predetermined crystal grain size, the depth of the carburized hardened layer, the Vickers hardness, etc. could not be secured, and the fatigue resistance was poor. This is an example of (F determination).
  • No. Nos. 8 and 9 are examples using the same steel type. This is an example of simulating No. 4 (steel type A, carburizing condition L of Patent Document 1).
  • No. Nos. 8 and 9 are examples in which the V addition amount is small and the Cr addition amount is large, and the carburized hardened layer was shallow because the diffusion coefficient of C was remarkably lowered. In particular, no. Since the carburizing temperature of No. 8 was low, a sufficient depth of the carburized hardened layer could not be secured, and the fatigue resistance was poor.
  • No. No. 9 was treated at the carburizing temperature recommended by the present invention, but since the amount of V added was small, the effect of refining the prior austenite crystal was not sufficiently obtained, and mixed grains were produced, resulting in poor fatigue resistance.
  • No. No. 10 had a small amount of V added, so that when it was processed at a predetermined carburizing temperature, mixed grains were generated and fatigue resistance was inferior.
  • No. 11 is an example in which the addition amount of C and Si is small and the carburizing temperature is low. In this example, the predetermined Vickers hardness was not obtained, and the fatigue resistance was inferior.
  • No. Nos. 12 and 13 had a low carburizing temperature, so that a predetermined carburized hardened layer depth was not obtained, and fatigue resistance was inferior.

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  • Materials Engineering (AREA)
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  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heat Treatment Of Articles (AREA)
  • Springs (AREA)
  • Heat Treatment Of Steel (AREA)
PCT/JP2014/068123 2013-07-09 2014-07-08 コイルばね、およびその製造方法 WO2015005311A1 (ja)

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CN201480039266.5A CN105358726B (zh) 2013-07-09 2014-07-08 螺旋弹簧及其制造方法
KR1020167000388A KR101789944B1 (ko) 2013-07-09 2014-07-08 코일 스프링 및 그 제조 방법
EP14823237.4A EP3020841B1 (en) 2013-07-09 2014-07-08 Coil spring, and method for manufacturing same
US14/903,975 US20160160306A1 (en) 2013-07-09 2014-07-08 Coil spring, and method for manufacturing same

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CN106939372B (zh) * 2017-02-14 2018-12-18 江西昌河航空工业有限公司 一种弹簧的制造方法
JP7165522B2 (ja) * 2018-07-10 2022-11-04 日本発條株式会社 圧縮コイルばねおよびその製造方法
CN112449654B (zh) * 2019-07-01 2022-07-08 住友电气工业株式会社 钢线和弹簧

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0959745A (ja) * 1995-08-24 1997-03-04 Daido Steel Co Ltd 結晶粒粗大化防止鋼
JP2003213372A (ja) * 2002-01-25 2003-07-30 Sumitomo Denko Steel Wire Kk ばね用鋼線およびばね
JP2012077367A (ja) 2010-10-06 2012-04-19 Nissan Motor Co Ltd コイルばね及びその製造方法
JP2013036113A (ja) * 2011-08-11 2013-02-21 Nhk Spring Co Ltd 圧縮コイルばねおよびその製造方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5545267A (en) * 1993-03-12 1996-08-13 Nippon Steel Corporation Steel product for induction-hardened shaft component and shaft component using the same
CN100445408C (zh) * 2003-03-28 2008-12-24 株式会社神户制钢所 加工性优异的高强度弹簧用钢丝以及高强度弹簧
WO2007114491A1 (ja) * 2006-03-31 2007-10-11 Nippon Steel Corporation 高強度ばね用熱処理鋼
JP5476597B2 (ja) * 2010-03-04 2014-04-23 株式会社神戸製鋼所 高強度中空ばね用シームレス鋼管
JP5711539B2 (ja) * 2011-01-06 2015-05-07 中央発條株式会社 腐食疲労強度に優れるばね

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0959745A (ja) * 1995-08-24 1997-03-04 Daido Steel Co Ltd 結晶粒粗大化防止鋼
JP2003213372A (ja) * 2002-01-25 2003-07-30 Sumitomo Denko Steel Wire Kk ばね用鋼線およびばね
JP2012077367A (ja) 2010-10-06 2012-04-19 Nissan Motor Co Ltd コイルばね及びその製造方法
JP2013036113A (ja) * 2011-08-11 2013-02-21 Nhk Spring Co Ltd 圧縮コイルばねおよびその製造方法

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KR101789944B1 (ko) 2017-10-25
JP2015017288A (ja) 2015-01-29
CN105358726B (zh) 2017-06-09
EP3020841B1 (en) 2018-08-22
JP5941439B2 (ja) 2016-06-29
EP3020841A1 (en) 2016-05-18
US20160160306A1 (en) 2016-06-09
EP3020841A4 (en) 2017-03-29
CN105358726A (zh) 2016-02-24

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