EP2985361B1 - Aushärtbarer stahl - Google Patents

Aushärtbarer stahl Download PDF

Info

Publication number
EP2985361B1
EP2985361B1 EP14850316.2A EP14850316A EP2985361B1 EP 2985361 B1 EP2985361 B1 EP 2985361B1 EP 14850316 A EP14850316 A EP 14850316A EP 2985361 B1 EP2985361 B1 EP 2985361B1
Authority
EP
European Patent Office
Prior art keywords
less
steel
aging treatment
age
content
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP14850316.2A
Other languages
English (en)
French (fr)
Other versions
EP2985361A1 (de
EP2985361A4 (de
Inventor
Masato Yuya
Masashi Higashida
Hitoshi Matsumoto
Tatsuya Hasegawa
Yutaka Neishi
Taizo Makino
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel and Sumitomo Metal Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel and Sumitomo Metal Corp filed Critical Nippon Steel and Sumitomo Metal Corp
Publication of EP2985361A1 publication Critical patent/EP2985361A1/de
Publication of EP2985361A4 publication Critical patent/EP2985361A4/de
Application granted granted Critical
Publication of EP2985361B1 publication Critical patent/EP2985361B1/de
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • 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
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • C21D9/0075—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rods of limited length
    • 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
    • C22C38/002—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
    • C22C38/02—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
    • C22C38/06—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
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/22—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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • 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
    • C21D2211/002—Bainite
    • 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

Definitions

  • the present invention relates to an age-hardenable steel. More specifically, the present invention relates to a steel which is processed into a desired shape by hot forging and cutting process, and is thereafter subjected to age-hardening treatment (hereafter, simply referred to as "aging treatment") to ensure desired strength and toughness by the aging treatment, and which is quite suitably used as a starting material for producing mechanical parts such as for automobiles, industrial machinery, construction machinery, and the like.
  • age-hardening treatment hereafter, simply referred to as "aging treatment”
  • Patent Document 1 discloses the following age-hardening steel.
  • an "age-hardening steel” containing: by mass%, C: 0.11 to 0.60%, Si: 0.03 to 3.0%, Mn: 0.01 to 2.5%, Mo: 0.3 to 4.0%, V: 0.05 to 0.5%, and Cr: 0.1 to 3.0%, and further containing, as needed, one or more kinds of Al: 0.001 to 0.3%, N: 0.005 to 0.025%, Nb: 0.5% or less, Ti: 0.5% or less, Zr: 0.5% or less, Cu: 1.0% or less, Ni: 1.0% or less, S: 0.01 to 0.20%, Ca: 0.003 to 0.010%, Pb: 0.3% or less and Bi: 0.3% or less, with the balance being Fe and inevitable impurities, wherein the following relationships are established among each component: 4 C + Mn + 0.7 Cr + 0.6 Mo ⁇ 0.2 V ⁇ 2.5, C ⁇ Mo / 16 + V / 5.7, V + 0.15 Mo ⁇ 0.4 and wherein after rolling, forging, or solution treatment
  • Patent Document 2 discloses the following bainite steel.
  • a "bainite steel” containing: by mass%, C: 0.14 to 0.35%, Si: 0.05 to 0.70%, Mn: 1.10 to 2.30%, S: 0.003 to 0.120%, Cu: 0.01 to 0.40%, Ni: 0.01 to 0.40%, Cr: 0.01 to 0.50%, Mo: 0.01 to 0.30%, and V: 0.05 to 0.45% and further containing, as needed, one or more kinds selected from Ti: 0.001 to 0.100%, and Ca: 0.0003 to 0.0100%, with the balance being Fe and inevitable impurities, wherein the following relationships are satisfied: 16 C + 8 Si + 10 Mn + 3 Cu + 3 Ni + 22 Mo + 11 V ⁇ 30, 5 C + Si + 2 Mn + 3 Cr + 2 Mo + 4 V ⁇ 7.3, 2.4 ⁇ 0.3 C + 1.1 Mn + 0.2 Cu + 0.2 Ni + 1.2 Cr + 1.1 Mo + 0.2 V ⁇ 3.1, 2.5 ⁇ C + Si + 4 Mo + 9 V , and
  • Patent Documents 3 and 4 disclose age-hardenable steels having a predetermined chemical composition or micro structure
  • Patent Documents 5 and 6 disclose, as a method for obtaining steel parts for mechanical structures, a method of performing aging treatment, in which steel material is cooled at a predetermined cooling velocity after hot forging, and thereafter is subjected to aging treatment in a predetermined temperature range.
  • Patent Document 7 provides a steel for nitriding with a composition including, by mass%: C: 0.10% to 0.20%; Si: 0.01% to 0.7%; Mn: 0.2% to 2.0%; Cr: 0.2% to 2.5%; Al: 0.01% to less than 0.19%; V: over 0.2% to 1.0%; Mo: 0% to 0.54%; N: 0.001% to 0.01%; P limited to not more than 0.05%; S limited to not less than 0.2%; and a balance including Fe and inevitable impurities, the composition satisfying 2 ⁇ [V]/[C] ⁇ 10, where [V] is an amount of V by mass% and [C] is an amount of C by mass%, in which the steel for nitriding has a microstructure containing bainite of 50% or more in terms of an area percentage.
  • Patent Document 8 is directed to surface of a steel, as a material for a crankshaft, that is nitrocarburized.
  • the steel contains, as alloy elements C having a content 0.10 mass % or more 0.30 mass % or less, Si having a content 0.5 mass % or more and 0.3 mass % or less, Mn having a content 0.3 mass % or more and 1.5 mass % or less, Mo having a content 0.8 mass % or more and 2.0 mass % or less, Cr having a content 0.1 mass % or more and 1.0 mass % or less, and V having a content 0.1 mass % or more and 0.5 mass % or less, with a remainder consisting of Fe and inevitable impurities.
  • the contents of the alloy elements fall within ranges: 2.0 mass % ⁇ Mn+Cr+Mo ⁇ 3.0 mass %, 2.3 mass % ⁇ C+Mo+5V ⁇ 3.7 mass %, and 2.7 mass % ⁇ 2.16 Cr+Mo+2.54V ⁇ 4.0 mass %. If a steel sample extracted from a central portion of the nitrocarburized steel free from an influence of the nitrocarburizing treatment is austenitized at 1200 DEG C. for one hour, and cooled to a room temperature so that a cooling rate at which the steel sample passes through a temperature range between 900 DEG C. and 300 DEG C.
  • a surface hardness of a nitrocarburized layer is 650 Hv or more, a formation depth of the nitrocarburized layer is 0.3 mm or more, and a hardness of the central portion is 340 Hv or more.
  • Patent Document 9 describes a process for producing a hot forged steel of ferrite+bainite structure type which includes: applying hot forging to a steel product of a composition by weight of C: 0.10-0.35%, Si: 0.15-2.00%, Mn: 0.40-2.00%, S: 0.03-0.10%, Al: 0.0005-0.050%, Ti: 0.003-0.050%, N: 0.0020-0.0070%, V: 0.30-0.70%, and further containing one or more of Cr, Mo, Nb, Pb and Ca in a specified amount; cooling thereafter so that 80% or more of the metallographic structure after finishing of the transformation is ferrite+bainite structure; and further applying aging treatment at a temperature of 200 DEG -700 DEG C.
  • a steel whose toughness has deteriorated has an increased notch susceptibility. With a higher notch susceptibility, the fatigue strength of steel becomes more likely to be affected by fine surface flaws.
  • Patent Document 1 Since the steel disclosed in Patent Document 1 is permitted to have a hardness before aging treatment of up to 40 HRC and thus a very high hardness, it is difficult to ensure machinability, specifically, cutting resistance is high so that tool life is decreased, thereby increasing cutting cost. While steels disclosed as a specific example include those whose hardness before aging treatment is less than 40 HRC, they contain not less than 1.4% of Mo, and in addition to that, their toughness is not taken into consideration at all.
  • the contents of alloying elements are adjusted so as to satisfy a particular parametric formula so that while the content of Mo is kept to be relatively low, the hardness before aging treatment (after hot forging) is not more than 300 HV, and the hardness after aging treatment is not less than 300 HV.
  • sufficient efforts have not been made to increase toughness after aging treatment.
  • an age-hardenable steel which has a chemical composition containing not more than 1.0 mass% of Mo and in which hardness before aging treatment is not more than 290 HV, hardness increases by 25 in HV by aging treatment, and the below-described fatigue strength is not less than 350 MPa, as well as absorbed energy at 20°C after aging treatment is not less than 16 J when evaluated by a Charpy impact test performed by using a standard specimen with a U-notch having a notch depth of 2 mm and a notch bottom radius of 1 mm according to JIS Z 2242.
  • the present invention has been made based on the above described findings, and its gist is an age-hardenable steel described below.
  • the age-hardenable steel of the present invention has hardness before aging treatment of not more than 290 HV. Furthermore, using the age-hardenable steel of the present invention causes the hardness to increase by not less than 25 in HV through aging treatment performed after cutting process, and can ensure a fatigue strength of not less than 350 MPa, and an excellent toughness, that is, absorbed energy at 20°C after aging treatment of not less than 16 J when evaluated by a Charpy impact test performed by using a standard specimen with a U-notch having a notch depth of 2 mm and a notch bottom radius of 1 mm. Therefore, the age-hardenable steel of the present invention can be quite suitably used as a starting material for mechanical parts such as for automobiles, industrial machinery, construction machinery, and the like.
  • Figure 1 shows the shape of a uniaxial tension-compression type fatigue test specimen used in Examples. Numerical values in the figure represent dimensions (unit: mm).
  • C is a crucial element in the present invention.
  • C combines with V and forms a carbide, thereby strengthening the steel.
  • C content is less than 0.05%, the carbide of V becomes not likely to precipitate, and therefore desired strengthening effect cannot be achieved.
  • C content is excessively large, the amount of C which does not combine with V and Mo, but combines with Fe to form carbide (cementite) increases, thereby deteriorating the toughness of steel. Therefore, C content is specified to be 0.05 to 0.20%.
  • the C content is preferably not less than 0.08%, and more preferably not less than 0.10%.
  • the C content is preferably not more than 0.18%, and more preferably not more than 0.16%.
  • Si is useful as a deoxidizing element during steel making, and also has an effect of dissolving into matrix and thereby increasing the strength of steel. To achieve such effects satisfactorily, Si content of not less than 0.01% is required. However, when the Si content is excessive, hot workability of steel is deteriorated and its hardness before aging treatment increases. Therefore, Si content is specified to be 0.01 to 0.50%. The Si content is preferably not less than 0.06%. Moreover, the Si content is preferably not more than 0.45%, and more preferably less than 0.35%.
  • Mn has effects of improving hardenability, and causing the micro-structure to contain bainite as a main phase. Further, Mn also has an effect of decreasing the bainite transformation temperature, thereby refining the bainite structure and improving toughness of the matrix. Further, Mn has an effect of forming MnS in steel, thereby improving chip treatability during cutting. To achieve such effects satisfactorily, Mn content needs to be at least 1.5%. However, since Mn is an element which is likely to segregate during solidification of steel, when its content is excessive, it is inevitable that variation of hardness increases within a steel part after hot forging. Therefore, Mn content is specified to be 1.5 to 2.5%. The Mn content is preferably not less than 1.6%, and more preferably not less than 1.7%. Moreover, the Mn content is preferably not more than 2.3%, and more preferably not more than 2.1%.
  • S content needs to be not less than 0.005%.
  • S content is specified to be 0.005 to 0.08%.
  • the S content is preferably not less than 0.01%.
  • the S content is preferably not more than 0.05%, and more preferably not more than 0.03%.
  • Cr has effects of improving hardenability, and causing the micro-structure to contain bainite as a main phase. Further, Cr also has an effect of decreasing the bainite transformation temperature, thereby refining the bainite structure and improving toughness of matrix.
  • Cr content is specified to be 0.03 to 0.50%.
  • the Cr content is preferably not less than 0.05%, and more preferably not less than 0.15%.
  • Al is an element having a deoxidizing effect, and to achieve such an effect, Al content needs to be not less than 0.005%. However, when Al content is excessive, coarse oxides are likely to be produced, thereby deteriorating toughness. Therefore, the Al content is specified to be 0.005 to 0.05%.
  • the Al content is preferably not more than 0.04%.
  • V 0.25 to 0.50%
  • V is the most crucial element in the steel of the present invention.
  • V has an effect of combining with C to form fine carbides during aging treatment, thereby increasing fatigue strength.
  • Mo when Mo is contained in steel, V has an effect of being compounded with Mo and precipitated by aging treatment, further increasing age hardenability.
  • V content needs to be not less than 0.25%.
  • V content is specified to be 0.25 to 0.50%.
  • the V content is preferably less than 0.45%, and more preferably not more than 0.40%.
  • the V content is preferably not less than 0.27%.
  • Mo has a relatively low precipitation temperature of carbide, and is an element which can be readily utilized for age-hardening. Mo has effects of improving hardenability, causing the micro-structure after hot forging to contain bainite as a main phase, and increasing its area fraction. Mo is compounded with V to form a carbide, thereby increasing age-hardenability. For that purpose, Mo may be contained as needed. However, since Mo is a very expensive element, an increase in its content will cause an increase in steel manufacturing cost, and also deterioration of toughness. Therefore, when Mo is contained, its content is specified to be not more than 1.0%. The content of Mo is preferably not more than 0.50%, more preferably not more than 0.40%, and further preferably less than 0.30%.
  • its content is preferably not less than 0.05%, and more preferably not less than 0.10%.
  • Each of Cu and Ni has an effect of increasing fatigue strength. Therefore, when higher fatigue strength is desired, these elements may be contained in the following range.
  • Cu has an effect of increasing fatigue strength. Therefore, Cu may be contained as needed. However, when Cu content increases, hot workability deteriorates. Therefore, when Cu is contained, its content is specified to be not more than 0.3%.
  • the Cu content is preferably not more than 0.25%.
  • its content is preferably not less than 0.1%.
  • Ni has an effect of increasing fatigue strength. Moreover, Ni also has an effect of suppressing the deterioration of hot workability due to Cu. Therefore, Ni may be contained as needed. However, increase of Ni content causes saturation of the above described effect in addition to increase of cost. Therefore, when Ni is contained, its content is specified to be not more than 0.3%. The Ni content is preferably not more than 0.25%.
  • its content is desirably not less than 0.1%.
  • the above described Cu and Ni only one of them, or two of them in combination may be contained.
  • the total content of the above described elements, when they are contained, may be 0.6% at which each of Cu and Ni contents has its upper limit value.
  • Each of Ca and Bi has an effect of prolonging tool life during cutting. Therefore, when further prolonged tool life is desired, these elements may be contained within the following range.
  • Ca has an effect of prolonging tool life. Therefore, Ca may be contained as needed. However, when Ca content increases, coarse oxides are formed, thereby deteriorating toughness. Therefore, when Ca is contained, its content is specified to be not more than 0.005%.
  • the Ca content is preferably not more than 0.0035%.
  • the Ca content is desirably not less than 0.0005%.
  • Bi has an effect of reducing cutting resistance and thereby prolonging tool life. Therefore, Bi may be contained as needed. However, when Bi content increases, hot workability deteriorates. Therefore, when Bi is contained, its content is specified to be not more than 0.4%. The Bi content is preferably not more than 0.3%.
  • the Bi content is preferably not less than 0.03%.
  • Ca and Bi only one of them, or two of them in combination may be contained.
  • the total content of these elements, when they are contained, may be 0.405% at which each of Ca and Bi contents has its upper limit value, but is preferably not more than 0.3%.
  • the age-hardenable steel of the present invention is a steel having a chemical composition consisting of the above described elements, with the balance being Fe and impurities, wherein P, Ti, and N included in the impurities are: P: 0.03% or less, Ti: less than 0.005%, and N: less than 0.0080%, and further wherein, F1 represented by the above described Formula (1) is not less than 0.68, F2 represented by the above described Formula (2) is not more than 0.85, and F3 represented by the above described Formula (3) is not less than 0.00.
  • impurities refer to those which are mixed from ores as the raw material, scrap, or manufacturing environments when steel material is industrially manufactured.
  • P is contained as an impurity and is an undesirable element in the present invention. That is, P segregates at grain boundaries, and thereby deteriorates toughness. Therefore, the P content is specified to be not more than 0.03%. The P content is preferably not more than 0.025%.
  • Ti is contained as an impurity and is a particularly undesirable element in the present invention. That is, Ti combines with N and/or C to form TiN and/or TiC, thereby causing deterioration of toughness, and particularly when its content is not less than 0.005%, toughness is significantly deteriorated. Therefore, Ti content is specified to be less than 0.005%. To ensure excellent toughness, the Ti content is preferably not more than 0.0035%.
  • N is contained as an impurity, and is an undesirable element which immobilizes V as a nitride in the present invention. That is, since V which has precipitated as a nitride will not contribute to age hardening, the N content needs to be kept low to suppress precipitation of nitride. For that purpose, the N content needs to be less than 0.0080%.
  • the N content is preferably not more than 0.0070%, and more preferably less than 0.0060%.
  • each symbol of element in the Formula (1) means the content of that element in mass%.
  • F1 is an index for hardenability. Provided that the amount of each alloying element contained in steel is within the range described above, if F1 satisfies the above described condition, the micro-structure after hot forging will contain bainite as a main phase.
  • F1 is preferably not less than 0.70, and more preferably not less than 0.72. Moreover, F1 is preferably not more than 1.0, and more preferably not more than 0.98.
  • each symbol of element in the Formula (2) means the content of that element in mass%.
  • F2 is an index showing hardness before aging treatment.
  • the age-hardenable steel of the present invention only satisfies the above described condition of F1
  • the hardness before aging treatment becomes excessively high and the cutting resistance during cutting process increases, thereby shortening tool life.
  • F2 is preferably not more than 0.82, and more preferably not more than 0.80. Moreover, F2 is preferably not less than 0.55, and more preferably not less than 0.60.
  • each symbol of element in the Formula (3) means the content of that element in mass%.
  • F3 is an index showing toughness after aging treatment. That is, only satisfying the conditions of F1 and F2 may result in deterioration of toughness after aging treatment, making it impossible to ensure targeted toughness.
  • F3 is preferably not less than 0.01.
  • the age-hardenable steel of the present invention preferably has an average block size of bainite of 15 to 60 ⁇ m.
  • block of bainite as used in the present invention refers to a region surrounded by boundaries with an orientation difference of not less than 15° when orientation analysis of the micro-structure is performed by an EBSD (Electron BackScatter Diffraction) method.
  • EBSD Electro BackScatter Diffraction
  • the average block size of bainite increases, the hardness before aging decreases, and therefore good machinability is obtained.
  • the average block size is excessively large, toughness will deteriorate.
  • the average block size is more preferably not less than 20 ⁇ m.
  • the average block size is more preferably not more than 45 ⁇ m, and further preferably not more than 30 ⁇ m.
  • the manufacturing method of the age-hardenable steel of the present invention will not be particularly limited, and it may be melted by a general method to adjust the chemical composition.
  • material to be subjected to hot forging hereafter, referred to as "material for hot forging" will be made.
  • the above described material for hot forging may be of any kind such as a billet obtained by blooming an ingot, a billet obtained by blooming a continuous casting material, or a steel bar obtained by hot rolling or hot forging those billets.
  • the above described material for hot forging is subjected to hot forging and further to cutting process to be finished into a predetermined part shape.
  • the material for hot forging is heated at 1100 to 1350°C for 0.1 to 300 minutes and thereafter forged such that the surface temperature after finish forging is not less than 900°C, thereafter being cooled to the room temperature with an average cooling velocity in a temperature range of 800 to 400°C being 10 to 90°C/min (0.2 to 1.5°C/sec). After being cooled in this way, the material is further subjected to cutting process to be finished into a predetermined part shape.
  • the lower limit of this average cooling velocity is preferably 20°C/min, and the upper limit is preferably 80°C/min.
  • the material is subjected to aging treatment to obtain a mechanical part such as for automobiles, industrial machinery, construction machinery, and the like, which have desired properties.
  • the above described aging treatment is performed in a temperature range of 540 to 700°C, and preferably in a temperature range of 560 to 680°C.
  • the retention time of this aging treatment is appropriately adjusted to be, for example, 30 to 1000 minutes depending on the size (mass) of the mechanical part.
  • Steels A to W in Tables 1 and 2 are steels whose chemical compositions are within the range defined in the present invention.
  • Steels X to AG in Table 2 are steels whose chemical compositions are out of the conditions defined in the present invention.
  • each steel bar was heated at 1250°C and thereafter hot forged into a steel bar having a diameter of 60 mm.
  • Each of the hot-forged steel bars was temporarily allowed to cool to room temperature in the atmosphere. Thereafter, the steel bar was further heated at 1250°C for 30 minutes and hot forged into a steel bar having a diameter of 35 mm with the surface temperature of the forged material at the time of finishing being kept at 950 to 1100°C supposing that it is forged into a part shape. After hot forging, each steel bar was allowed to cool to room temperature in the atmosphere.
  • the cooling velocity during cooling in the atmosphere was measured by embedding a thermocouple at a depth of around R/2 ("R" indicates a radius of steel bar) in a steel bar, and reheating the steel bar, which had been hot-forged at the above described condition, up to around the finishing temperature for hot forging and thereafter allowing it to be cooled in the atmosphere.
  • R/2 indicates a radius of steel bar
  • measured average cooling velocity in a temperature range of 800 to 400°C after forging was about 40°C/min (0.7°C/sec).
  • the hardness measurement was conducted in the following way. First, a specimen was prepared by transecting a steel bar, embedding it in a resin such that the cut plane became the surface to be inspected, and thereafter mirror-polishing it. Next, hardness measurement was conducted with the testing force being 9.8 N at 10 points around R/2 portion ("R" represents radius) in the surface to be inspected conforming to the "Vickers hardness test - testing method" in JIS Z 2244 (2009). Vickers hardness was determined by arithmetically averaging the values of the 10 points. It was judged that the hardness before the aging treatment was sufficiently low when the hardness was not more than 290 HV, and this was set as a target. It was also judged that the quantity of hardening was sufficiently large, when the difference of hardness in HV (hereafter, referred to as " ⁇ HV”) between before and after the aging treatment became not less than 25, and this was set as a target.
  • ⁇ HV difference of hardness in HV
  • the measurement of area fraction of bainite in the micro-structure was conducted in the following way.
  • the specimen which was embedded in resin and mirror-polished for hardness measurement was etched with NITAL.
  • Micro-structure of the specimen after etching was photographed at a magnification of 200 by using an optical microscope.
  • the area fraction of bainite was measured by image analysis from a photographed picture. It was judged that the micro-structure became fully bainitic when the area fraction of bainite was not less than 70%, and this was set as a target.
  • the fatigue strength was investigated by sampling a uniaxial tension-compression type fatigue test specimen. That is, a smooth fatigue test specimen of a shape whose parallel portion, as shown in Figure 1 , has a diameter of 3.4 mm and a length of 12.7 mm was taken in parallel with the forging direction (in the longitudinal direction of steel bar) from a R/2 portion of the steel bar, and was subjected to a fatigue test under conditions of room temperature, the atmosphere, a stress ratio of 0.05, and a test speed of 10 Hz.
  • the fatigue strength was determined as the maximum stress applied to the specimens which have not ruptured up to a number of stress repetition of 10 7 under the conditions described above. It was judged that the fatigue strength was sufficiently high when the fatigue strength was not less than 350 MPa, and this was set as a target.
  • the hardness before the aging treatment was not more than 290 HV, and the hardness increased by not less than 25 in HV, the fatigue strength increased to not less than 350 MPa, and further the absorbed energy in the Charpy impact test increased to not less than 16 J as the result of aging treatment, thus respectively achieving the targets so that strength and toughness after the aging treatment were successfully achieved at the same time. Further, the fact that the hardness before the aging treatment was low revealed that reduction of cutting resistance and prolongation of tool life can be expected.
  • the cut out steel bar was further heated at 1250°C for 30 minutes and was hot forged into a steel bar having a diameter of 35 mm with the surface temperature of the forged material at the time of finishing being kept at 950 to 1100°C supposing that it is forged into a part shape.
  • the steel bar was allowed to cool in the atmosphere, or by using a blower and mist to a temperature not more than 400°C at various cooling velocities.
  • the hardness before aging treatment was measured by using some of the steel bars which, after being finished into a diameter of 35 mm by hot forging, was cooled to a temperature not more than 400°C by using a blower and mist and further cooled to room temperature.
  • Example 1 The investigations of the hardnesses before and after the aging treatment, the absorbed energy in the Charpy impact test, and the fatigue strength were conducted under the same conditions as in Example 1. Moreover, target values of these were the same as in Example 1.
  • An interface between blocks has a complicated shape with unevenness. For that reason, when an observation surface of micro-structure is created in such a way to cut off the vicinity of an uneven end part of a block, it may be observed as if a block enclosed in another block was present. In such a case, measurement accuracy of the area of block will deteriorate. To eliminate such effects, when a certain block was fully enclosed in another block in a cross-sectional image, they were regarded as one block, and the area was determined from a larger block alone, neglecting the enclosed smaller block.
  • the size of block was defined as the diameter of a circle which has the same area. From the size of each block in region of 30000 ⁇ m 2 analyzed by the EBSD method, an average block size was calculated.
  • the size of each block was weighted according to the area of the block. That is, for n blocks 1 to n in an analysis region, supposing that the sizes of each block are D1, D2, ..., Dn ( ⁇ m), and the areas thereof are S1, S2, ..., Sn ( ⁇ m 2 ), the average block size was determined as (D1 ⁇ S1 + D2 ⁇ S2 + ...+ Dn ⁇ Sn)/30000.
  • the target of average block size was set to be 15 to 60 ⁇ m.
  • Table 4 shows results of each investigations described above.
  • Test No. C1 corresponds to Test No. A16 of Table 3.
  • the cooling velocity shown in Table 4 is an average cooling velocity in a temperature range of 800 to 400°C during cooling after hot forging the steel bar having a diameter of 35 mm.
  • the measurement method of the average cooling velocity was the same as that in Example 1.
  • the average cooling velocity satisfied the average cooling velocity (10 to 90°C/min, that is, 0.2 to 1.5°C/sec) shown as one example of the method for manufacturing an age-hardenable steel of the present invention described above.
  • the average cooling velocity was faster than the aforementioned example of average cooling velocity. Comparing Test Nos. C1 to C6 to each other, it is seen that the slower the average cooling velocity, the larger the average block size of bainite becomes. Moreover, it is seen that the larger the average block size of bainite, the lower the hardness before the aging treatment becomes, and thus better machinability can be expected.
  • the age-hardenable steel of the present invention has hardness before aging treatment of not more than 290 HV, and therefore can be expected to have reduced cutting resistance and a prolonged tool life. Furthermore, using the age-hardenable steel of the present invention causes the hardness to increase by not less than 25 in HV through aging treatment performed after cutting process, and can ensure a fatigue strength of not less than 350 MPa, and an excellent toughness, that is, absorbed energy at 20°C after aging treatment of not less than 16 J when evaluated by a Charpy impact test performed by using a standard specimen with a U-notch having a notch depth of 2 mm and a notch bottom radius of 1 mm. Therefore, the age-hardenable steel of the present invention can be quite suitably used as a starting material for producing mechanical parts such as for automobiles, industrial machinery, construction machinery, and so on.

Landscapes

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

Claims (7)

  1. Aushärtbarer Stahl mit einer chemischen Zusammensetzung, die in Masse-% besteht aus: C: 0,05 bis 0,20 %, Si: 0,01 bis 0,50 %, Mn: 1,5 bis 2,5 %, S: 0,005 bis 0,08 %, Cr: 0,03 bis 0,50 %, Al: 0,005 bis 0,05 %, V: 0,25 bis 0,50 %, Mo: 0 bis 1,0 %, Cu: 0 bis 0,3 %, Ni: 0 bis 0,3 %, Ca: 0 bis 0,005 % und Bi: 0 bis 0,4 %, wobei es sich bei dem Rest um Fe und Verunreinigungen handelt, wobei
    es sich bei in den Verunreinigungen enthaltenem P, Ti und N um P: 0,03 % oder weniger, Ti: weniger als 0,005 % und N: weniger als 0,0080 % handelt, und wobei darüber hinaus
    durch die folgende Formel (1) dargestelltes F1 nicht weniger als 0,68 beträgt, durch die folgende Formel (2) dargestelltes F2 nicht mehr als 0,85 beträgt, und durch die folgende Formel (3) dargestelltes F3 nicht weniger als 0,00 beträgt; F 1 = C + 0,3 Mn + 0,25 Cr + 0,6 Mo
    Figure imgb0018
     F 2 = C + 0,1 Si + 0,2 Mn + 0,15 Cr + 0,35 V + 0,2 Mo
    Figure imgb0019
     und F 3 = − 4,5 C + Mn + Cr − 3,5 V − 0,8 Mo
    Figure imgb0020
    wobei jedes Elementsymbol in den Formeln (1) bis (3) den Gehalt des Elements in Masse-% bedeutet,
    wobei der Stahl Bainit als Hauptphase enthält, und
    wobei die Härte nicht mehr als 290 HV beträgt.
  2. Aushärtbarer Stahl nach Anspruch 1, wobei die chemische Zusammensetzung in Masse-% eine oder mehrere Art/en enthält, die aus den in den folgenden Punkten <1> bis <3> gezeigten Elementen ausgewählt ist bzw. sind;
    <1> Mo: 0,05 bis 1,0 %,
    <2> Cu: 0,1 bis 0,3 %, und Ni: 0,1 bis 0,3 %, und
    <3> Ca: 0,0005 bis 0,005 %, und Bi: 0,03 bis 0,4 %.
  3. Aushärtbarer Stahl nach Anspruch 1, wobei eine mittlere Blockgröße des Bainits 15 bis 60 µm beträgt.
  4. Verwendung des aushärtbaren Stahls nach einem der vorhergehenden Ansprüche, wobei der Stahl einer Aushärtungsbehandlung unterzogen wird, wobei die Aushärtungsbehandlung in einem Temperaturbereich von 540 bis 700°C erfolgt und eine Haltezeit hat, die auf 30 bis 1000 Minuten eingestellt ist.
  5. Verwendung nach Anspruch 4, wobei der Stahl als Ausgangsmaterial zum Herstellen mechanischer Teile wie etwa für Automobile, Industriemaschinen, Baumaschinen verwendet wird.
  6. Verwendung nach Anspruch 4 oder 5 des Stahls nach Anspruch 4, wobei es sich bei der Härte von nicht mehr als 290 HV um eine Härte vor der Aushärtungsbehandlung handelt.
  7. Verwendung nach Anspruch 6, wobei nach der Aushärtungsbehandlung
    - die Härte um 25 HV zunimmt, und
    - die Ermüdungsfestigkeit nicht weniger als 350 MPa beträgt, und
    - bei 20°C aufgenommene Energie nicht weniger als 16 J, ausgewertet durch einen Charpy-Kerbschlagtest beträgt, der unter Verwendung einer Standardprobe mit einer U-Kerbe, die eine Kerbentiefe von 2 mm und einem Kerbengrundradius von 1 mm hat, nach JIS Z 2242 durchgeführt wird.
EP14850316.2A 2013-10-02 2014-10-01 Aushärtbarer stahl Active EP2985361B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2013207125 2013-10-02
PCT/JP2014/076260 WO2015050151A1 (ja) 2013-10-02 2014-10-01 時効硬化性鋼

Publications (3)

Publication Number Publication Date
EP2985361A1 EP2985361A1 (de) 2016-02-17
EP2985361A4 EP2985361A4 (de) 2016-11-30
EP2985361B1 true EP2985361B1 (de) 2018-03-14

Family

ID=52778739

Family Applications (1)

Application Number Title Priority Date Filing Date
EP14850316.2A Active EP2985361B1 (de) 2013-10-02 2014-10-01 Aushärtbarer stahl

Country Status (7)

Country Link
US (1) US20160201175A1 (de)
EP (1) EP2985361B1 (de)
JP (1) JP5880795B2 (de)
KR (1) KR101709883B1 (de)
CN (1) CN105164297B (de)
HU (1) HUE037998T2 (de)
WO (1) WO2015050151A1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109093099A (zh) * 2018-09-30 2018-12-28 宁波市镇海甬鼎紧固件制造有限公司 一种耐低温高强度螺帽及其生产方法
CN110257713A (zh) * 2019-07-16 2019-09-20 内蒙古科技大学 一种低碳时效钢及其制备方法

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3300500B2 (ja) * 1993-10-12 2002-07-08 新日本製鐵株式会社 疲労強度、降伏強度および被削性に優れる熱間鍛造用鋼の製造方法
CN1163942A (zh) * 1996-02-08 1997-11-05 阿斯克迈塔尔公司 制造锻件用钢及锻件制造方法
DE60121234T2 (de) * 2000-05-26 2006-11-09 Jfe Steel Corp. Kaltgewalztes Stahlblech und Zinkblech mit Reckalterungseigenschaften und Verfahren zur dessen Herstellung
JP4041413B2 (ja) * 2002-08-27 2008-01-30 株式会社神戸製鋼所 切り屑処理性に優れた機械構造用鋼、およびその製造方法
JP2004169055A (ja) * 2002-11-15 2004-06-17 Aichi Steel Works Ltd 被削性に優れた時効硬化型高強度ベイナイト鋼部品およびその製造方法
FR2847910B1 (fr) * 2002-12-03 2006-06-02 Ascometal Sa Procede de fabrication d'une piece forgee en acier et piece ainsi obtenue.
JP4415219B2 (ja) 2004-07-28 2010-02-17 大同特殊鋼株式会社 時効硬化鋼
JP2006291310A (ja) * 2005-04-12 2006-10-26 Daido Steel Co Ltd クランクシャフト及びその製造方法
JP5251089B2 (ja) * 2006-12-04 2013-07-31 新日鐵住金株式会社 低温靱性に優れた高強度厚肉ラインパイプ用溶接鋼管及びその製造方法
WO2010090238A1 (ja) 2009-02-04 2010-08-12 住友金属工業株式会社 時効硬化性鋼および機械部品の製造方法
JP5655366B2 (ja) * 2010-05-07 2015-01-21 大同特殊鋼株式会社 ベイナイト鋼
JP5387501B2 (ja) * 2010-05-17 2014-01-15 新日鐵住金株式会社 鋼板および表面処理鋼板ならびにそれらの製造方法
JP5343923B2 (ja) 2010-05-18 2013-11-13 新日鐵住金株式会社 時効硬化性鋼および機械部品の製造方法
EP2578717B1 (de) * 2010-11-17 2015-09-16 Nippon Steel & Sumitomo Metal Corporation Stahl für nitrierungsvorgänge und nitriertes element
JP5664371B2 (ja) * 2011-03-17 2015-02-04 新日鐵住金株式会社 時効硬化性鋼および機械部品の製造方法
CN103201401B (zh) 2011-05-26 2014-07-02 新日铁住金株式会社 机械结构用钢部件及其制造方法
JP5620336B2 (ja) 2011-05-26 2014-11-05 新日鐵住金株式会社 高疲労強度、高靭性機械構造用鋼部品およびその製造方法
JP5767594B2 (ja) * 2012-02-15 2015-08-19 Ｊｆｅ条鋼株式会社 窒化用鋼材およびこれを用いた窒化部材
JP5974623B2 (ja) * 2012-05-07 2016-08-23 大同特殊鋼株式会社 時効硬化型ベイナイト非調質鋼
KR20130021427A (ko) * 2013-01-16 2013-03-05 최기웅 타임밤 서비스 방법

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
JPWO2015050151A1 (ja) 2017-03-09
KR101709883B1 (ko) 2017-02-23
EP2985361A1 (de) 2016-02-17
KR20150110804A (ko) 2015-10-02
US20160201175A1 (en) 2016-07-14
WO2015050151A1 (ja) 2015-04-09
EP2985361A4 (de) 2016-11-30
CN105164297B (zh) 2017-05-24
HUE037998T2 (hu) 2018-09-28
CN105164297A (zh) 2015-12-16
JP5880795B2 (ja) 2016-03-09

Similar Documents

Publication Publication Date Title
EP2985362B1 (de) Alterungsfähiger stahl
JP5123335B2 (ja) クランクシャフトおよびその製造方法
EP3222742B1 (de) Gewalzter stahlstab oder gewalztes drahtmaterial für kaltgeschmiedete komponente
EP2617852A1 (de) Hochfestes heissgewalztes stahlblech von hervorragender biegbarkeit sowie verfahren zu seiner herstellung
WO2014104113A1 (ja) 浸炭用鋼
EP2784169B1 (de) Gewalzter stahlstab zum warmschmieden
WO2015125915A1 (ja) 高周波焼入れ用鋼材
US20180066344A1 (en) Wire rod for use in bolts that has excellent acid pickling properties and resistance to delayed fracture after quenching and tempering, and bolt
EP3222743B1 (de) Gewalzter stahlstab oder gewalztes drahtmaterial für kaltgeschmiedete komponente
KR20130058069A (ko) 냉간 단조성이 우수한 침탄용 강 및 그 제조 방법
JP6631640B2 (ja) 肌焼鋼、浸炭部品および肌焼鋼の製造方法
EP3202937A1 (de) Stahl für bolzen sowie bolzen
CN109790602B (zh) 钢
JP6536673B2 (ja) 時効硬化用鋼及び時効硬化用鋼を用いた部品の製造方法
JP6506978B2 (ja) ＮｉＣｒＭｏ鋼およびＮｉＣｒＭｏ鋼材の製造方法
JP5304507B2 (ja) 高周波焼入れ用非調質鋼
EP3272896B1 (de) Aushärtbarer stahl und verfahren zur herstellung von komponenten mit aushärtbarem stahl
EP2985361B1 (de) Aushärtbarer stahl
WO2010090238A1 (ja) 時効硬化性鋼および機械部品の製造方法
JP2009191322A (ja) 浸炭部品用の耐粗粒化特性に優れたはだ焼鋼
JP6844943B2 (ja) 高周波焼入れ用非調質鋼
JP5030695B2 (ja) 破断分離性に優れる高炭素鋼およびその製造方法
JP5131770B2 (ja) 軟窒化用非調質鋼
JP6245278B2 (ja) 時効硬化性鋼
JP2010280978A (ja) 直接切削用非調質棒鋼

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20150803

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

A4 Supplementary search report drawn up and despatched

Effective date: 20161027

RIC1 Information provided on ipc code assigned before grant

Ipc: C22C 38/20 20060101ALI20161021BHEP

Ipc: C21D 8/06 20060101ALI20161021BHEP

Ipc: C22C 38/02 20060101ALI20161021BHEP

Ipc: C22C 38/22 20060101ALI20161021BHEP

Ipc: C21D 9/00 20060101ALI20161021BHEP

Ipc: C21D 1/18 20060101ALI20161021BHEP

Ipc: C21D 1/06 20060101ALI20161021BHEP

Ipc: C22C 38/44 20060101ALI20161021BHEP

Ipc: C22C 38/50 20060101ALI20161021BHEP

Ipc: C22C 38/60 20060101ALI20161021BHEP

Ipc: C22C 38/28 20060101ALI20161021BHEP

Ipc: C22C 38/46 20060101ALI20161021BHEP

Ipc: C22C 38/24 20060101ALI20161021BHEP

Ipc: C22C 38/58 20060101ALI20161021BHEP

Ipc: C22C 38/00 20060101AFI20161021BHEP

Ipc: C22C 38/38 20060101ALI20161021BHEP

Ipc: C22C 38/42 20060101ALI20161021BHEP

Ipc: C22C 38/06 20060101ALI20161021BHEP

DAX Request for extension of the european patent (deleted)
GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RIC1 Information provided on ipc code assigned before grant

Ipc: C22C 38/06 20060101ALI20170907BHEP

Ipc: C21D 8/06 20060101ALI20170907BHEP

Ipc: C22C 38/20 20060101ALI20170907BHEP

Ipc: C22C 38/28 20060101ALI20170907BHEP

Ipc: C22C 38/38 20060101ALI20170907BHEP

Ipc: C21D 1/18 20060101ALI20170907BHEP

Ipc: C22C 38/58 20060101ALI20170907BHEP

Ipc: C22C 38/24 20060101ALI20170907BHEP

Ipc: C21D 9/00 20060101ALI20170907BHEP

Ipc: C22C 38/00 20060101AFI20170907BHEP

Ipc: C22C 38/22 20060101ALI20170907BHEP

Ipc: C21D 1/06 20060101ALI20170907BHEP

Ipc: C22C 38/46 20060101ALI20170907BHEP

Ipc: C22C 38/50 20060101ALI20170907BHEP

Ipc: C22C 38/60 20060101ALI20170907BHEP

Ipc: C22C 38/02 20060101ALI20170907BHEP

Ipc: C22C 38/42 20060101ALI20170907BHEP

Ipc: C22C 38/44 20060101ALI20170907BHEP

INTG Intention to grant announced

Effective date: 20170927

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

Ref country code: AT

Ref legal event code: REF

Ref document number: 978947

Country of ref document: AT

Kind code of ref document: T

Effective date: 20180315

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602014022448

Country of ref document: DE

REG Reference to a national code

Ref country code: NL

Ref legal event code: MP

Effective date: 20180314

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180614

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

REG Reference to a national code

Ref country code: AT

Ref legal event code: MK05

Ref document number: 978947

Country of ref document: AT

Kind code of ref document: T

Effective date: 20180314

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180614

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180615

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

REG Reference to a national code

Ref country code: HU

Ref legal event code: AG4A

Ref document number: E037998

Country of ref document: HU

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: AL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602014022448

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180716

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

26N No opposition filed

Effective date: 20181217

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 602014022448

Country of ref document: DE

Representative=s name: ZIMMERMANN & PARTNER PATENTANWAELTE MBB, DE

Ref country code: DE

Ref legal event code: R081

Ref document number: 602014022448

Country of ref document: DE

Owner name: NIPPON STEEL CORPORATION, JP

Free format text: FORMER OWNER: NIPPON STEEL & SUMITOMO METAL CORPORATION, TOKYO, JP

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20181001

REG Reference to a national code

Ref country code: BE

Ref legal event code: MM

Effective date: 20181031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181001

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181031

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181031

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181031

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181001

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180314

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20180314

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20180714

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: HU

Payment date: 20230926

Year of fee payment: 10

Ref country code: DE

Payment date: 20230830

Year of fee payment: 10