EP0462779B1 - Wärmebehandlungsverfahren für Stahl, insbesondere von Stahl für Federn - Google Patents

Wärmebehandlungsverfahren für Stahl, insbesondere von Stahl für Federn Download PDF

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Publication number
EP0462779B1
EP0462779B1 EP91305456A EP91305456A EP0462779B1 EP 0462779 B1 EP0462779 B1 EP 0462779B1 EP 91305456 A EP91305456 A EP 91305456A EP 91305456 A EP91305456 A EP 91305456A EP 0462779 B1 EP0462779 B1 EP 0462779B1
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European Patent Office
Prior art keywords
plate
steel
cold
rolled strip
temperature
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Expired - Lifetime
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EP91305456A
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English (en)
French (fr)
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EP0462779A2 (de
EP0462779A3 (en
Inventor
Tsunetoshi c/o Tekkokenkyusho Suzaki
Tomoyoshi c/o Tekkokenkyusho Iwao
Teruo Nisshin Steel Co. Ltd. Tanaka
Toshiro c/o Tekkokenkyusho Yamada
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Nippon Steel Nisshin Co Ltd
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Nisshin Steel Co Ltd
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Priority claimed from JP15879090A external-priority patent/JP2961666B2/ja
Priority claimed from JP2507691A external-priority patent/JP2952862B2/ja
Priority claimed from JP2507791A external-priority patent/JP2823965B2/ja
Application filed by Nisshin Steel Co Ltd filed Critical Nisshin Steel Co Ltd
Publication of EP0462779A2 publication Critical patent/EP0462779A2/de
Publication of EP0462779A3 publication Critical patent/EP0462779A3/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
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/02—Hardening by precipitation
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273—Final recrystallisation annealing
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/24—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
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling

Definitions

  • the present invention relates to a method of making steel which is useful in springs, such as the diaphragm spring component in clutches for motor vehicles.
  • the diaphragm spring is made of carbon tool steel such as SK5 (Japanese Industrial Standard). However, springs of carbon steel can relax quickly, in that they may become inoperative when the temperature thereof reaches or exceeds the high environmental temperature of 150°C.
  • US-A-4,770,721 discloses a spring steel comprising 0.5-0.8% carbon, 0.5-1.4% silicon, 0.5-1.5% manganese and one or more of 0.05-0.5% vanadium, 0.05-0.5% niobium and 0.05-0.5% molybdenum, the remainder being iron together with impurities.
  • the steel may further contain 0.0005-0.01% boron, 0.2-1.0% chromium 0.2-2.0% nickel and not greater than 0.3% rare-earth elements and/or 0.02-0.1% titanium and 0.02-0.1% zirconium.
  • An object of the present invention is to provide a method of making steel having a property resisting high temperature, whereby a spring made of the steel is more resistant to relaxation at relatively high temperatures.
  • Another object of the present invention is to provide steel which may be quickly quenched at a low temperature, thereby preventing significant endurance reduction in the steel.
  • the method for making steel comprises hot-rolling steel material comprising by weight: 0.4 % to 0.8 % carbon, 0.5 % to 2.5 % silicon, 0.3 % to 2.0 % manganese, 0.1 % to 1.5 % chromium, 0.1 % to 0.5 % molybdenum, and further optionally including by weight one or more of the following:
  • the lower critical cooling speed is a speed above which the austenite is fully transformed to the martensite.
  • molybdenum carbide is finely precipitated, thereby preventing the dislocation migration which causes the relaxation of the spring at high temperature.
  • the heating is preferably preformed at a temperature between 450°C and 600°C for a time sufficient to precipitate the carbide.
  • the silicon content and chromium content are preferably selected so as to satisfy the equation: -7 ⁇ 4xSi(%) - 10xCr(%) ⁇ 5.
  • the heating of the cooled cold-rolled strip or plate is preferably performed so as to provide an annealed hardness between HV400 and HV550.
  • the annealing of the cold-rolled strip or plate is preferably performed at a temperature between 550°C and 730°C, thereby providing carbide having an average grain diameter less than 2 ⁇ m.
  • the figure is a graph showing relationship between heating temperature and hardness of steel.
  • Carbon is effective in increasing the strength of steel. In order to obtain a strength necessary for the the spring, carbon content of 0.4 % or more by weight must be included. However, if carbon is included in excess of 0.8 %, quenching crack and reduction of toughness of steel occur. Therefore the carbon is included in the range 0.4 % to 0.8 % by weight.
  • the material is tempered at high temperature. Silicon is added to prevent the strength from reducing due to the high temperature tempering. It is necessary to add silicon of 0.5 % or more by weight. If the silicon content exceeds 2.5 %, internal oxidation and decarburization which are unfavourable to the spring occur, and graphitization is enhanced in the hot rolling and annealing.
  • Manganese is effective in deoxidizing steel and in increasing the hardenability of the steel, if the manganese is included at 0.3 % or more by weight. If the manganese content exceeds 2.0 %, toughness of the steel reduces significantly after quenching and tempering.
  • Chromium acts to restrict the graphitization and the internal oxidation which are enhanced by silicon, and is effective in increasing the hardenability as is effected by manganese, if chromium is included at 0.1 % or more by weight. If the chromium content exceeds 1.5 %, toughness of the steel reduces after quenching and tempering.
  • Si content and Cr content are most preferably determined to satisfy the following equation, thereby preventing decarburization and graphitization. -7 ⁇ 4xSi(%)-10xCr(%) ⁇ 5
  • the molybdenum included in the steel of the present invention forms carbide in the steel after cold rolling and annealing.
  • the carbon becomes solid solution in austenite when the steel is heated over the Ac3 critical point. Consequently, the austenite is transformed into martensite after quenching, and carbide separates finely upon tempering at high temperature, thereby significantly increasing endurance whilst withstanding against relaxation.
  • it is necessary to include molybdenum of at least 0.1 % but no more than 0.5 % by weight. If the molybdenum content exceeds 0.5 %, a large amount of carbide remains without becoming solid solution in austenite when the steel is heated above the Ac3 critical point.
  • vanadium, Niobium optional but preferred component(s) vanadium and niobium, if included in the steel of the present invention become carbide after the cold rolling and annealing thereof. Remaining vanadium and niobium without becoming solid solution in austenite act to prevent austenite grain from growing. On the other hand, solid solution of vanadium and niobium in austenite are in solid solution in martensite when quenching, and precipitate finely as carbide when tempering, thereby enhancing endurance whilst withstanding against relaxation. In order to attain these effects, vanadium and or niobium each in an amount of 0.05 % or more are necessary. If the individual content of either or both exceeds 0.5 %, the quantity of undissolved carbide in austenite increases when the steel is heated above Ac3 point, thereby reducing fatigue strength of the steel.
  • (Aluminium) - a component which is preferably substantially absent.
  • the steel spring is fatigued by repeated bending or twisting. Existence of hard inclusions such as aluminum aggravates this fatigue. To reduce the influence of any such hard inclusion, the aluminium content of the steel is preferably less than 0.020 weight percent. Preferred manufacturing conditions are now described, for steel plate or strip.
  • the annealing after the cold rolling is performed at a temperature above 730°C (Ac1 critical point), spheroidized grain of carbide becomes coarse. Consequently, it takes a long time to transform the carbide to austenite, resulting in increase of decarburization causing deterioration of spring characteristic. Therefore, the annealing after the cold rolling is carried out at a temperature below the Ac1 point. If the annealing temperature is lower than 550°C, the hardness increases, so that the formability of the material reduces. Therefore, the annealing temperature is between 550°C and 730°C.
  • the average grain diameter of carbide after the annealing is less than 2 ⁇ m, carbide is easily dissolved austenite at quenching. Therefore, it is necessary to maintain the average grain diameter of carbide to a value smaller than 2 ⁇ m for effectively performing the quenching.
  • the strip is heated at a temperature higher than the critical point Ac3 for a time sufficient for austenitizing the spheroidal carbide, after which it is cooled at a speed higher than a lower critical cooling speed, namely quenching. Thereafter, the strip is heated at a temperature between 450°C and 600°C for a time to precipitate fine carbide and cooled to a room temperature (that is tempering). At the quenching, the parent material is austenitized by heating it over the Ac3 point, and then carbon and other elements are dissolved to martensite by cooling at a speed higher than the lower critical cooling speed.
  • Table 1 shows contents of steels.
  • a to F are steels of the present invention
  • G to L are comparative steels.
  • Each of the steels A to F is made into a hot-rolled plate of 3.5 mmt by ordinary hot rolling and then the plate is annealed and cold rolled at a rolling reduction between 5 % and 90 %. Thereafter, the steel is annealed at 700°C below the Ac1 point for 10 hours, and is soaked at 900°C above the Ac3 point for a period necessary to provide remaining carbide ratio below 1 % by weight. Thereafter, the steel is quenched into oil.
  • Table 2 shows results of tests for edge crack and depth of decarburization.
  • edge crack occurs. If the rolling reduction is smaller than 10 %, carbide becomes coarse. Consequently, it takes a long time to dissolve carbide into austenite, so that the depth of decarburization increases significantly.
  • Each of the steels A to F is made into a hot-rolled plate of 3.5 mmt by ordinary hot rolling and annealed and cold rolled at rolling reduction of 35 % to form a cold rolled plate of 2.3 mm. Thereafter, the steel is annealed once at 700°C for 10 hours, and is heated at a temperature between 850°C and 900°C for 10 minutes. Thereafter, the steel is quenched into oil and tempered at a temperature between 420°C and 630°C for 30 minutes.
  • a relaxation test was performed in order to estimate endurance against relaxation. The test was carried out at 350°C, initial 1.0 % strain, holding time of 12 hours. Load reduction after the test was regarded as relaxation rate.
  • Table 3 shows the result of the relaxation test. Since comparative example G is smaller than the present invention in carbon content, comparative example 1 is smaller in silicon content, comparative example J is in manganese content, and K is in chromium content, each of these steels has low strength so that the relaxation rate thereof is high. Although the comparative example H has a large carbon content, the relaxation rate is not largely reduced. Since the comparative example L has no molybdenum, the carbide of which is effective to increase the endurance, relaxation rate is very high. Although each of comparative examples A', D' and F' has the same ingredient content as the present invention, the tempering temperature is out of the range of the present invention. Consequently, the relaxation rate is not largely reduced.
  • each steel according to the present invention has a very low relaxation rate comparing with the comparative examples, which means that the steel has a high endurance withstanding against the relaxation.
  • TABLE 3 Steel Quenching Temp. (°C) Tempering Temp.(°C) Hardness HV) Relaxation Rate (%) present invention A 900 480 496 16.2 900 520 475 15.1 900 560 452 14.4 850 520 462 15.7 B 900 560 470 13.5 C 900 520 479 15.7 D 900 480 513 14.2 900 520 492 13.4 900 560 468 12.6 850 560 452 13.2 E 900 560 453 14.1
  • Embodiments A to G in Table 4 are steels of the present invention and H to L are comparative steels.
  • Each of the steels in the table was hot-rolled to provide a hot-rolled plate having a thickness of 3.5 mmt, and then annealing the hot-rolled plate.
  • the plate was cold rolled at rolling reduction of 35 % to prepare a cold-rolled plate of 2.3 mmt thickness.
  • the cold-rolled plate was annealed at a temperature between 650°C and 750°C for 10 hours to provide a test piece.
  • Hardenability test was performed in such a manner that the test piece was rapidly heated to 850°C at the rate of 140C°/sec, heated from 850°C to a test temperature between 900°C and 1100°C at the rate of 30C°/sec, and then rapidly cooled immediately after the heating without taking a holding time. The hardenability was estimated by the hardness of the test piece after the quenching. Results of the test are shown in the attached figure.
  • the test piece A having ingredient contents according to the present invention has an average grain diameter of carbide less than 2 ⁇ m when annealed at 650°C and 700°C. Even if the test piece A is heated to the lowest temperature 900°C, the hardness becomes the higher value. However, if it is annealed at 750°C so that the average grain diameter exceeds 2 ⁇ m, the hardness does not reach the highest value unless the quenching temperature is elevated up to 950°C.
  • the comparative example H has a SICR value of -7.42 out of the range of the present invention. Consequently a large amount of chromium remains in carbide after the annealing. Accordingly, the steel must be heated up to 1000°C in order to obtain the higher hardness, although the average grain diameter is smaller than 2 ⁇ m.
  • Fatigue test and relaxation test piece are estimated as follows.
  • the cold-rolled plate having 2.3 mm thickness is annealed at 680°C for 10 hours, and then heated at 900°C and quenched. Thereafter, a plurality of the plates are tempered at various temperatures for 30 minutes.
  • the steel A of the present invention has a hardness approximately equal to the comparative example I, the steel A is superior to the comparative example I in fatigue strength. This is caused by the fact that the aluminum content of the steel A is less than 0.020 weight percent, which means hard inclusion causing fatigue fracture is small.
  • the steel G has the same fatigue characteristic as steel A.
  • the comparative steel J has a small Cr content compared with Si content, so that SICR value is 7.50 out of the range of the present invention, producing graphite at annealing.
  • SICR value is 7.50 out of the range of the present invention, producing graphite at annealing.
  • decarburization increased.
  • the fatigue characteristic is inferior to the steels A and G.
  • a to G are steels of the present invention
  • H to L are comparative steels.
  • Each of the steels in the table was hot rolled to provide a hot-rolled plate having a thickness of 3.5 mmt, and the hot-rolled plate was then annealed.
  • the plate was cold rolled at rolling reduction of 35 % to prepare a cold-rolled plate of 2.3 mmt thickness.
  • the cold-rolled plate was annealed at 680°C for 10 hours, and then heated at a temperature between 850°C and 900°C for 10 minutes and quenched into oil. All plates were tempered at various temperatures for 30 minutes.
  • the steel E of the present invention has a hardness approximately equal to the comparative example I, the steel E is superior to the comparative example I in fatigue strength due to the lower aluminium content.
  • the fatigue strength may reduce if the annealed hardness exceeds HV550.
  • Comparative steels H and J have small C content and Si content, and hence they have high relaxation rates, respectively. Since comparative steel K has no Mo, it has a high relaxation rate. Even if each of steels A, D, E and G include components within the present invention, the relaxation rate is not significantly reduced if the tempering temperature increases and hardness is lower than an annealed hardness of HV400, as shown in comparative examples II.

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
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  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
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Claims (8)

  1. Verfahren zur Herstellung von Stahlband oder -blech, bei dem man
       Stahlmaterial mit 0,4 bis 0,8 Gew.-% Kohlenstoff, 0,5 bis 2,0 Gew.-% Silizium, 0,3 bis 2,0 Gew.-% Mangan, 0,1 bis 1,5 Gew.-% Chrom, 0,1 bis 0,5 Gew.-% Molybdän und ferner wahlweise mit einem oder mehreren der folgenden Elemente:
    0,05 bis 0,5 Gew.-% Vanadium,
    0,05 bis 0,5 Gew.-% Niob und
    0,02 Gew.-% oder weniger Aluminium
    und im übrigen Eisen und unvermeidbaren Verunreinigungen unter Bildung eines Bandes oder Bleches warmwalzt,
    das warmgewalzte Band oder Blech glüht,
    das geglühte, warmgewalzte Band oder Blech bei einer Walz-reduktion zwischen 10% und 80% kaltwalzt,
    das kaltgewalzte Band oder Blech bei einer Temperatur unter dem kritischen Ac1-Punkt glüht,
    das geglühte, kaltgewalzte Band oder Blech auf eine Temperatur über dem kritischen Ac3-Punkt während einer zur Karbidaustenitisierung ausreichenden Zeit erwärmt,
    das erwärmte, kaltgewalzte Band oder Blech abkühlt,
    das abgekühlte, kaltgewalzte Band oder Blech eine zur Karbidausfällung nötige Zeit erwärmt und dann auf Raumtemperatur abkühlt.
  2. Verfahren nach Anspruch 1, bei dem das Stahlmaterial 0,05 bis 0,5 Gew.-% Vanadium und/oder 0,05 bis 0,5 Gew.-% Niob enthält.
  3. Verfahren nach Anspruch 1 oder 2, bei dem das Stahlmaterial nicht mehr als 0,020 Gew.-% Aluminium enthält.
  4. Verfahren nach einem vorhergehenden Anspruch, bei dem die Erwärmung des abgekühlten, kaltgewalzten Bandes oder Bleches bei einer Temperatur von 450°C bis 600°C durchgeführt wird.
  5. Verfahren nach einem vorhergehenden Anspruch, bei dem der Silizium- und Chromgehalt des Stahls so ausgewählt wird, daß er der Gleichung -7≦4xSi(%) - 10xCr(%)≦5
    Figure imgb0008
     genügt.
  6. Verfahren nach einem vorhergehenden Anspruch, bei dem die Abkühlung des erwärmten, kaltgewalzten Bandes oder Bleches mit einer Geschwindigkeit durchgeführt wird, die höher als eine geringere kritische Abkühlgeschwindigkeit ist.
  7. Verfahren nach einem vorhergehenden Anspruch, bei dem die Erwärmung des gekühlten, kaltgewalzten Bandes oder Bleches zur Schaffung einer Glühhärte von HV400 bis HV550 durchgeführt wird.
  8. Verfahren nach einem vorhergehenden Anspruch, bei dem das Glühen des kaltgewalzten Bandes oder Bleches bei einer Temperatur von 550°C bis 730°C durchgeführt wird, um so Karbid mit einem mittleren Korndurchmesser von weniger als 2 µm zu bilden.
EP91305456A 1990-06-19 1991-06-17 Wärmebehandlungsverfahren für Stahl, insbesondere von Stahl für Federn Expired - Lifetime EP0462779B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP158790/90 1990-06-19
JP15879090A JP2961666B2 (ja) 1990-06-19 1990-06-19 耐温間へたり性に優れたばね用鋼の製造方法
JP25077/91 1991-01-28
JP2507691A JP2952862B2 (ja) 1991-01-28 1991-01-28 焼入れ性，耐温間へたり性に優れたバネ用鋼の製造方法
JP25076/91 1991-01-28
JP2507791A JP2823965B2 (ja) 1991-01-28 1991-01-28 ダイヤフラムスプリング用鋼の製造方法

Publications (3)

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EP0462779A2 EP0462779A2 (de) 1991-12-27
EP0462779A3 EP0462779A3 (en) 1993-09-01
EP0462779B1 true EP0462779B1 (de) 1996-09-11

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KR (1) KR930012177B1 (de)
AU (1) AU633737B2 (de)
CA (1) CA2044639C (de)
DE (1) DE69121982T2 (de)

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JP2932943B2 (ja) * 1993-11-04 1999-08-09 株式会社神戸製鋼所 高耐食性高強度ばね用鋼材
SE502969C2 (sv) * 1994-02-17 1996-03-04 Uddeholm Steel Strip Användning av en stållegering som material till bestrykningsschabrar i form av kallvalsade band
GB2352726A (en) 1999-08-04 2001-02-07 Secr Defence A steel and a heat treatment for steels
KR100682150B1 (ko) * 2000-12-20 2007-02-12 가부시키가이샤 고베 세이코쇼 경인발스프링용 강선재, 경인발스프링용 신선재와 경인발스프링 및 경인발스프링의 제조방법
EP1491647B1 (de) * 2002-04-02 2006-07-26 Kabushiki Kaisha Kobe Seiko Sho Stahldraht für hartgezogene feder mit hervorragender dauerfestigkeit und senkungsbeständigkeit und hartgezogene feder
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JP4291639B2 (ja) * 2003-08-28 2009-07-08 トヨタ自動車株式会社 鉄基焼結合金およびその製造方法
KR101106871B1 (ko) * 2006-06-09 2012-01-19 가부시키가이샤 고베 세이코쇼 피로 특성이 우수한 고청정도 스프링용 강 및 고청정도 스프링
JP5624503B2 (ja) 2011-03-04 2014-11-12 日本発條株式会社 ばねおよびその製造方法
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KR930012177B1 (ko) 1993-12-24
KR920000959A (ko) 1992-01-29
CA2044639A1 (en) 1991-12-20
AU633737B2 (en) 1993-02-04
EP0462779A2 (de) 1991-12-27
DE69121982D1 (de) 1996-10-17
EP0462779A3 (en) 1993-09-01
CA2044639C (en) 2001-08-28
DE69121982T2 (de) 1997-01-30

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