WO2023157297A1 - Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules - Google Patents

Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules Download PDF

Info

Publication number
WO2023157297A1
WO2023157297A1 PCT/JP2022/006953 JP2022006953W WO2023157297A1 WO 2023157297 A1 WO2023157297 A1 WO 2023157297A1 JP 2022006953 W JP2022006953 W JP 2022006953W WO 2023157297 A1 WO2023157297 A1 WO 2023157297A1
Authority
WO
WIPO (PCT)
Prior art keywords
content
steel pipe
still
less
oxide film
Prior art date
Application number
PCT/JP2022/006953
Other languages
English (en)
Japanese (ja)
Inventor
守 早川
光洋 濱石
真也 坂本
Original Assignee
日本製鉄株式会社
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 日本製鉄株式会社 filed Critical 日本製鉄株式会社
Priority to PCT/JP2022/006953 priority Critical patent/WO2023157297A1/fr
Priority to PCT/JP2023/006173 priority patent/WO2023157975A1/fr
Publication of WO2023157297A1 publication Critical patent/WO2023157297A1/fr

Links

Images

Classifications

    • 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
    • C21D8/10—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies
    • 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
    • C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
    • 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
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
    • 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
    • C22C38/18—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

Definitions

  • the present disclosure relates to steel pipes, vehicle parts, and methods of manufacturing steel pipes and vehicle parts.
  • Vehicles such as automobiles are equipped with vehicle parts.
  • Vehicle parts are, for example, stabilizers, inner tie rods, drive shafts and upper arms. Vehicle components are subjected to repetitive stress due to vibrations that occur during vehicle travel. Therefore, vehicle parts are required to have excellent fatigue strength.
  • stabilizers include solid stabilizers made from steel bars and the like, and hollow stabilizers made from steel pipes and the like.
  • the use of hollow stabilizers has increased.
  • Patent Document 1 International Publication No. 2020/230795
  • Patent Document 2 International Publication No. 2013/175821
  • the electric resistance welded steel pipe for a hollow stabilizer disclosed in Patent Document 1 has C: 0.20 to 0.40%, Si: 0.1 to 1.0%, and Mn: 0.1 to 2.0% by mass. %, P: 0.1% or less, S: 0.01% or less, Al: 0.01 to 0.10%, Cr: 0.01 to 0.50%, Ti: 0.010 to 0.050% , B: 0.0005 to 0.0050%, Ca: 0.0001 to 0.0050%, N: 0.0050% or less, and Sn: 0.010 to 0.050%, the balance being Fe and unavoidable It has a chemical composition consisting of organic impurities, and the total decarburized layer depth on the inner and outer surfaces is 100 ⁇ m or less.
  • Patent Document 1 by containing 0.010% or more of Sn in the electric resistance welded steel pipe for hollow stabilizers, the formation of a decarburized layer is suppressed and the fatigue strength is increased.
  • the hollow stabilizer disclosed in Patent Document 2 has, as chemical components, C: 0.26 to 0.30%, Si: 0.05 to 0.35%, and Mn: 0.5 to 1.0% by mass. %, Cr: 0.05 to 1.0%, Ti: 0.005 to 0.05%, B: 0.0005 to 0.005%, Ca: 0.0005 to 0.005%, Al : 0.08% or less, P: 0.05% or less, S: less than 0.0030%, N: 0.006% or less, O: 0.004% or less, the balance being Fe and unavoidable impurities, Mn It has a component composition in which the product of the content and the S content is 0.0025 or less, and the critical cooling rate Vc90 represented by (Equation 1) is 40° C./s or less.
  • the metallographic structure of the hollow stabilizer consists of tempered martensite.
  • the length of the stretched MnS present in the thickness central portion of the hollow stabilizer is 150 ⁇ m or less.
  • the hollow stabilizer has a Rockwell C scale hardness (HRC) of 40 to 50, a wall thickness/outer diameter ratio of 0.14 or more, and a decarburized layer depth of 20 ⁇ m or less from the inner surface.
  • HRC Rockwell C scale hardness
  • the fatigue strength of the hollow stabilizer is improved by suppressing the formation of stretched MnS and controlling the Rockwell C scale hardness, the wall thickness/outer diameter ratio, and the depth of the decarburized layer on the inner surface. increasing.
  • Patent Documents 1 and 2 can increase the fatigue strength of vehicle parts.
  • a vehicle component having excellent fatigue strength may be obtained by means different from those disclosed in Patent Documents 1 and 2.
  • An object of the present disclosure is to provide a vehicle part with excellent fatigue strength, a steel pipe from which the vehicle part with excellent fatigue strength can be manufactured, and a method of manufacturing the steel pipe and the vehicle part.
  • the steel pipe of the present disclosure has the following configuration.
  • the vehicle component of the present disclosure has the following configuration.
  • the steel pipe manufacturing method of the present disclosure has the following steps.
  • the manufacturing method of the vehicle component of the present disclosure has the following steps.
  • a method for manufacturing a vehicle part comprising: a step of preparing the steel pipe as described above; a step of bending the steel pipe; a step of holding the bent steel pipe at a temperature of Ac 3 +50° C. or higher and 1150° C. or lower for 10 seconds or longer and then quenching; a step of holding and tempering the steel pipe after the quenching at 150 to 350° C. for 10 minutes or longer; A method for manufacturing vehicle parts.
  • the vehicle component of the present disclosure has excellent fatigue strength.
  • the steel pipe of the present disclosure can be used to manufacture vehicle parts with excellent fatigue strength.
  • the vehicle component manufacturing method of the present disclosure can manufacture a vehicle component having excellent fatigue strength.
  • the method for manufacturing a steel pipe according to the present disclosure can manufacture a steel pipe from which vehicle parts having excellent fatigue strength can be manufactured.
  • FIG. 1 is a perspective view of the end of the steel pipe of this embodiment.
  • FIG. 2 is a perspective view of an end portion of the vehicle component of this embodiment.
  • FIG. 3 is a front view of a torsional fatigue test piece.
  • FIG. 4 is a longitudinal side view of the torsional fatigue test piece.
  • the inventors have studied vehicle parts with excellent fatigue strength, and steel pipes from which vehicle parts with excellent fatigue strength can be manufactured. As a result, the following findings were obtained.
  • hollow vehicle parts are manufactured by cold bending a steel pipe and then quenching and tempering it.
  • Patent Document 1 "In particular, surface decarburization is considered to be an important factor among surface properties. If surface decarburization occurs during the heating stage of quenching, it is possible to improve the surface hardness even if quenching is performed. As a result, sufficient fatigue properties cannot be obtained” (paragraph [0005] of Patent Document 1).
  • Patent Literature 2 states, “Fatigue fracture may occur from the inner surface of the hollow stabilizer, which does not exist in the solid stabilizer. This is because even if the fatigue strength of the outer surface is improved by increasing the strength of the steel pipe, This is because the decarburized layer becomes the starting point of fatigue fracture" (paragraph [0005] of Patent Document 2). It is known that the formation of a decarburized layer in this way lowers the fatigue strength of a vehicle component including a hollow stabilizer.
  • Patent Document 1 "The surface decarburization reaction when steel is heated progresses by outward diffusion of carbon atoms in the steel toward the surface and reaction with oxygen. This outward diffusion of carbon It is effective to increase the lattice constant of iron to suppress the "(paragraph [0017] of Patent Document 1). Therefore, in Patent Document 1, 0.010% or more of Sn, which is effective for increasing the lattice constant of iron, is contained to suppress the formation of a decarburized layer.
  • Patent Document 2 states that "a decarburized layer is likely to be formed on the inner surface of the hollow stabilizer steel pipe when it is cooled from a high temperature at which the metal structure becomes an austenitic single phase and passes through a two-phase temperature range.” (Paragraph [0053] of Patent Document 2). Patent Document 2 describes that the formation of a decarburized layer can be suppressed by increasing the cooling rate when passing through the two-phase temperature (paragraph [0054] of Patent Document 2).
  • the inventors have studied means for suppressing the formation of decarburized layers other than the means disclosed in Patent Documents 1 and 2.
  • the decarburized layer is formed by quenching during manufacturing of vehicle parts. During heating and/or cooling for quenching, carbon in the steel out-diffuses to the surface and reacts with oxygen. This forms a decarburized layer.
  • the present inventors paid attention to the behavior of oxygen during quenching. The present inventors thought that formation of a decarburized layer could be suppressed by suppressing contact between the surface of a steel pipe for manufacturing vehicle parts and oxygen during quenching.
  • the present inventors paid attention to the oxide film before quenching.
  • An oxide film that suppresses contact between the steel pipe surface and oxygen is formed before quenching. It is believed that this suppresses contact between the surface of the steel pipe and oxygen during quenching, thereby suppressing the formation of a decarburized layer.
  • the X-ray diffraction peak intensity ratio is 70% or more.
  • Fe 3 O 4 , 20% or more Fe 2 O 3 , 10% or less FeO, and the balance consisting of impurities, the thickness is 0.80 to 2.50 ⁇ m, and the standard deviation of the thickness is 0.90 ⁇ m or less It has been found that the formation of an oxide film extends the rupture life of steel pipes after quenching.
  • Heating during quenching thermally expands steel pipes for manufacturing vehicle parts. If the difference between the coefficient of linear expansion of the steel pipe and the coefficient of linear expansion of the oxide film on the surface of the steel pipe is small, the difference between the amount of change in the surface area of the steel pipe due to heating during quenching and the amount of change in the volume of the oxide film is small. In this case, the oxide film is less likely to separate from the steel pipe surface, and the oxide film tends to remain on the steel pipe surface until just before quenching. In this case, contact between the steel pipe surface and oxygen is suppressed. It is conceivable that the coefficient of linear expansion of the oxide film having the composition described above is close to the coefficient of linear expansion of the steel pipe.
  • the oxide film remaining on the steel pipe surface until just before quenching suppresses the contact between the steel pipe surface and oxygen and suppresses the formation of a decarburized layer, increasing the fatigue strength of the steel pipe and extending the rupture life. be done.
  • the oxide film in order to obtain the effect of suppressing contact between the steel pipe surface and oxygen, the oxide film must have a certain thickness or more. On the other hand, if the oxide film is too thick, the oxide film tends to peel off. Therefore, it is necessary to control the thickness of the oxide film within a certain range.
  • the contact between the steel pipe surface and oxygen cannot be suppressed in the part where the oxide film is thin.
  • intergranular oxidation occurs locally on the surface of the steel pipe.
  • a dent occurs locally.
  • the fatigue strength of the vehicle component decreases due to the concentration of stress on the recess. Therefore, it is considered that local intergranular oxidation of the steel pipe surface can be suppressed by reducing the deviation of the thickness of the oxide film.
  • the inventors have found the following matter.
  • a vehicle part is manufactured by quenching the steel pipe provided with the oxide film described above, when the sum of the X-ray diffraction peak intensities of Fe 3 O 4 , FeO, and Fe 2 O 3 is taken as 100%, the X-ray Formation of an oxide film having a diffraction peak intensity ratio of 80% or more , FeO of 15% or less, Fe 2 O 3 of 5 % or less, and the balance being impurities, and having a thickness of 3.50 ⁇ m or less. It turns out that it will be.
  • This vehicle component has a long rupture life and excellent fatigue strength.
  • the steel pipe, steel pipe manufacturing method, vehicle component, and vehicle component manufacturing method of the present embodiment completed based on the above findings have the following configurations.
  • the vehicle component according to [3], The chemical composition, in mass %, Sol. Al: 0.001 to 0.080%, Cr: 0.01 to 1.50%, Mo: 0.01 to 1.00%, Ni: 0.01 to 1.00%, Cu: 0.01 to 1.00%, Ti: 0.001 to 0.100%, Nb: 0.001 to 0.100%, V: 0.001 to 0.100%, B: 0.0001 to 0.0050%, and Ca: 0.0001 to 0.0050%, containing one or more elements selected from the group consisting of vehicle parts.
  • a method for manufacturing a vehicle part comprising: A step of preparing the steel pipe according to [1] or [2]; a step of bending the steel pipe; a step of holding the bent steel pipe at a temperature of Ac 3 +50° C. or higher and 1150° C. or lower for 10 seconds or longer and then quenching; a step of holding and tempering the steel pipe after the quenching at 150 to 350° C. for 10 minutes or longer; A method for manufacturing vehicle parts.
  • FIG. 1 is a perspective view of the end of the steel pipe of this embodiment.
  • steel pipe 1 includes base material 2 and oxide film 3 on base material 2 .
  • Steel pipe 1 includes an outer surface 4 and an inner surface 5 .
  • the oxide film 3 may be formed only on the outer surface 4 of the steel pipe 1, may be formed only on the inner surface 5, or may be formed on both the outer surface 4 and the inner surface 5.
  • a decarburized layer on the outer surface of the vehicle component can be removed by shot peening, for example. On the other hand, the decarburized layer on the inner surface of the vehicle component may be difficult to remove.
  • Steel pipe 1 is therefore preferably provided with an oxide layer 3 on at least the inner surface 5 .
  • the steel pipe 1 may be a seamless steel pipe or an electric resistance welded steel pipe.
  • the steel pipe 1 is an electric resistance welded steel pipe.
  • the outer diameter of steel pipe 1 is not particularly limited, but is, for example, 10 to 100 mm.
  • the thickness of steel pipe 1 is not particularly limited, but is, for example, 2 to 10 mm.
  • the steel pipe 1 of this embodiment has the following features.
  • the content of each element in the chemical composition of the base material 2 is within the range shown in this specification.
  • the microstructure of the base material 2 consists of 20% to 60% ferrite and 40% to 80% pearlite in area ratio.
  • the X-ray diffraction peak intensity ratio is 70% or more.
  • An oxide film 3 composed of Fe 3 O 4 , 20% or more Fe 2 O 3 , 10% or less FeO, and the balance of impurities is disposed.
  • the oxide film 3 has a thickness of 0.80 to 2.50 ⁇ m.
  • the standard deviation of the thickness of the oxide film 3 is 0.90 ⁇ m or less.
  • C 0.23-0.50% Carbon (C) enhances the hardenability of steel. C further dissolves in steel. Thereby, C increases the strength of steel. If the C content is less than 0.23%, the above effect cannot be sufficiently obtained even if the content of other elements is within the range of the present embodiment. On the other hand, if the C content exceeds 0.50%, the hot workability of the steel deteriorates even if the content of other elements is within the range of the present embodiment. If the C content exceeds 0.50%, the toughness of the vehicle component after quenching decreases even if the content of other elements is within the range of the present embodiment. Therefore, the C content is 0.23-0.50%.
  • the lower limit of the C content is preferably 0.25%, more preferably 0.27%, still more preferably 0.30%, still more preferably 0.33%, still more preferably 0.33%. It is 35%, more preferably 0.38%, and still more preferably 0.40%.
  • the upper limit of the C content is preferably 0.48%, more preferably 0.46%, still more preferably 0.44%, still more preferably 0.42%, still more preferably 0.42%. 40%, more preferably 0.38%.
  • Si 0.01-0.50% Silicon (Si) deoxidizes steel. Si also forms a solid solution in steel to increase the strength of the steel. If the Si content is less than 0.01%, the above effect cannot be sufficiently obtained even if the content of other elements is within the range of the present embodiment. On the other hand, if the Si content exceeds 0.50%, the ductility and toughness of the steel pipe 1 are lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Si content is 0.01-0.50%.
  • the lower limit of the Si content is preferably 0.05%, more preferably 0.10%, still more preferably 0.15%, still more preferably 0.20%, still more preferably 0 .25%.
  • the upper limit of the Si content is preferably 0.45%, more preferably 0.40%, still more preferably 0.35%, still more preferably 0.30%.
  • Mn 0.50-2.50%
  • Manganese (Mn) increases the hardenability of steel. Mn further dissolves in steel. Thereby, Mn increases the strength of steel. If the Mn content is less than 0.50%, the above effect cannot be sufficiently obtained even if the content of other elements is within the range of the present embodiment. On the other hand, if the Mn content exceeds 2.50%, the toughness and ductility of the vehicle component after quenching are lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Mn content is 0.50-2.50%.
  • the lower limit of the Mn content is preferably 0.60%, more preferably 0.70%, still more preferably 0.75%, still more preferably 0.80%, still more preferably 0.80%.
  • the upper limit of the Mn content is preferably 2.40%, more preferably 2.30%, still more preferably 2.20%, still more preferably 2.10%, still more preferably 2.10%. 00%, more preferably 1.90%, more preferably 1.80%, still more preferably 1.70%, still more preferably 1.60%, still more preferably 1.0%. 50%.
  • P 0.050% or less Phosphorus (P) is an impurity. Therefore, the P content is over 0%. If the P content exceeds 0.050%, P segregates at the grain boundaries and reduces the ductility of the steel even if the content of other elements is within the range of the present embodiment. Therefore, the P content is 0.050% or less. The lower the P content, the better. However, drastic reduction of the P content greatly increases manufacturing costs. Therefore, when considering industrial production, the lower limit of the P content is preferably 0.001%, more preferably 0.002%, still more preferably 0.003%, still more preferably 0.005 %. The upper limit of the P content is preferably 0.040%, more preferably 0.030%, still more preferably 0.020%, still more preferably 0.010%.
  • S 0.0100% or less Sulfur (S) is an impurity. Therefore, the S content is over 0%. If the S content exceeds 0.0100%, the hot workability, toughness and fatigue strength of the steel are lowered even if the contents of other elements are within the range of the present embodiment. Therefore, the S content is 0.0100% or less. The lower the S content, the better. However, drastic reduction of the S content greatly increases manufacturing costs. Therefore, when considering industrial production, the lower limit of the S content is preferably 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005 %. The upper limit of the S content is preferably 0.0080%, more preferably 0.0070%, still more preferably 0.0060%, still more preferably 0.0050%, still more preferably 0.0050%. 0040%.
  • N 0.0100% or less Nitrogen (N) is an impurity. Therefore, the N content is over 0%. If the N content exceeds 0.0100%, the toughness of the steel is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the N content is 0.0100% or less.
  • N forms nitrides and/or carbonitrides to increase the strength of steel.
  • the preferred lower limit of the N content is 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005%, still more preferably 0.0010 %, more preferably 0.0020%, more preferably 0.0030%.
  • the upper limit of the N content is preferably 0.0080%, more preferably 0.0070%, still more preferably 0.0060%, still more preferably 0.0050%, still more preferably 0.0050%. 0040%.
  • Oxygen (O) is an impurity. Therefore, the O content is over 0%. If the O content exceeds 0.0100%, the toughness of the steel is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the O content is 0.0100% or less. The lower the O content, the better. However, drastic reduction of O content greatly increases manufacturing cost. Therefore, when considering industrial production, the preferred lower limit of the O content is 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005% is. The upper limit of the O content is preferably 0.0080%, more preferably 0.0070%, still more preferably 0.0060%, still more preferably 0.0050%, still more preferably 0.0050%. 0040%, more preferably 0.0030%.
  • the rest of the chemical composition of the steel pipe 1 of this embodiment consists of Fe and impurities.
  • the impurities in the chemical composition are those that are mixed from ore, scrap, or the manufacturing environment as raw materials when the steel pipe 1 is industrially manufactured, and have an adverse effect on the steel pipe 1 of the present embodiment. It means what is permissible within the range not given.
  • the chemical composition of the base material 2 of the steel pipe 1 according to this embodiment may further contain Al instead of part of Fe.
  • Al is an optional element and may not be contained. That is, the Al content may be 0%.
  • Al deoxidizes the steel.
  • Al further combines with nitrogen (N) to produce AlN.
  • AlN suppresses coarsening of crystal grains during quenching. If even a small amount of Al is contained, the above effect can be obtained to some extent.
  • Al content exceeds 0.080%, even if the content of other elements is within the range of the present embodiment, Al combines with oxygen (O) to excessively generate inclusions. This reduces the fatigue strength of the vehicle component. Therefore, the Al content is 0-0.080%.
  • the lower limit of the Al content is preferably more than 0%, more preferably 0.001%, still more preferably 0.005%, still more preferably 0.010%, still more preferably 0.015 %.
  • the upper limit of the Al content is preferably 0.070%, more preferably 0.060%, still more preferably 0.050%, still more preferably 0.040%, still more preferably 0.040%. 030%.
  • the chemical composition of the base material 2 of the steel pipe 1 according to this embodiment may further contain one or more elements selected from the group consisting of Cr, Mo, Ni and Cu instead of part of Fe. All of these elements are optional elements and may not be contained. All of these elements increase the strength of the steel pipe 1 when included.
  • Chromium (Cr) is an optional element and may not be contained. That is, the Cr content may be 0%. When Cr is contained, that is, when the Cr content is over 0%, Cr increases the strength of the steel pipe 1 . If even a little Cr is contained, the above effect can be obtained to some extent. On the other hand, if the Cr content exceeds 1.50%, the ductility of the steel pipe 1 is lowered even if the contents of other elements are within the range of the present embodiment. Therefore, the Cr content is 0-1.50%.
  • the lower limit of the Cr content is preferably 0.01%, more preferably 0.05%, still more preferably 0.10%, still more preferably 0.20%, still more preferably 0.20%. 30%.
  • the upper limit of the Cr content is preferably 1.20%, more preferably 1.00%, still more preferably 0.80%, still more preferably 0.60%, still more preferably 0.60%. 40%.
  • Mo Molybdenum
  • Mo is an optional element and may not be contained. That is, the Mo content may be 0%.
  • Mo When Mo is contained, that is, when the Mo content exceeds 0%, Mo enhances the strength of the steel pipe 1 . If even a little Mo is contained, the above effect can be obtained to some extent.
  • the Mo content exceeds 1.00%, the ductility of the steel pipe 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Mo content is 0-1.00%.
  • the lower limit of the Mo content is preferably 0.01%, more preferably 0.02%, still more preferably 0.03%, still more preferably 0.04%, still more preferably 0.04%. 05%.
  • the upper limit of the Mo content is preferably 0.80%, more preferably 0.60%, still more preferably 0.40%, still more preferably 0.20%, still more preferably 0.20%. 10%.
  • Nickel (Ni) is an optional element and may not be contained. That is, the Ni content may be 0%. When Ni is contained, that is, when the Ni content exceeds 0%, Ni enhances the strength of the steel pipe 1 . If Ni is contained even in a small amount, the above effect can be obtained to some extent. On the other hand, if the Ni content exceeds 1.00%, the ductility of the steel pipe 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Ni content is 0-1.00%.
  • the lower limit of the Ni content is preferably 0.01%, more preferably 0.02%, still more preferably 0.05%, still more preferably 0.10%, still more preferably 0.05%. 15%.
  • the upper limit of the Ni content is preferably 0.80%, more preferably 0.60%, still more preferably 0.40%, still more preferably 0.20%.
  • Cu Copper (Cu) is an optional element and may not be contained. That is, the Cu content may be 0%. When Cu is contained, that is, when the Cu content is over 0%, Cu increases the strength of the steel pipe 1 . If even a small amount of Cu is contained, the above effects can be obtained to some extent. On the other hand, if the Cu content exceeds 1.00%, the ductility of the steel pipe 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Cu content is 0-1.00%.
  • the lower limit of the Cu content is preferably 0.01%, more preferably 0.02%, still more preferably 0.03%, still more preferably 0.04%, still more preferably 0.04%. 05%.
  • the upper limit of the Cu content is preferably 0.80%, more preferably 0.60%, still more preferably 0.40%, still more preferably 0.20%.
  • the chemical composition of the base material 2 of the steel pipe 1 according to the present embodiment may further contain one or more elements selected from the group consisting of Ti, Nb and V instead of part of Fe. All of these elements are optional elements and may not be contained. When contained, all of these elements enhance the strength and workability of the steel pipe 1 .
  • Titanium (Ti) is an optional element and may not be contained. That is, the Ti content may be 0%. When Ti is contained, ie when the Ti content is greater than 0%, Ti forms carbides, nitrides and/or carbonitrides. This enhances the strength and workability of the steel pipe 1 . If even a small amount of Ti is contained, the above effect can be obtained to some extent. On the other hand, if the Ti content exceeds 0.100%, the ductility of the steel pipe 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Ti content is 0-0.100%.
  • the lower limit of the Ti content is preferably 0.001%, more preferably 0.005%, still more preferably 0.010%, still more preferably 0.020%, still more preferably 0.020%. 030%.
  • the upper limit of the Ti content is preferably 0.090%, more preferably 0.080%, still more preferably 0.070%, still more preferably 0.060%.
  • Niobium (Nb) is an optional element and may not be contained. That is, the Nb content may be 0%. If Nb is included, ie if the Nb content is greater than 0%, Nb forms carbides, nitrides and/or carbonitrides. This enhances the strength and workability of the steel pipe 1 . If even a small amount of Nb is contained, the above effect can be obtained to some extent. On the other hand, if the Nb content exceeds 0.100%, the ductility of the steel pipe 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Nb content is 0-0.100%.
  • the lower limit of the Nb content is preferably 0.001%, more preferably 0.002%, still more preferably 0.005%, still more preferably 0.010%, still more preferably 0.01%. 015%.
  • the upper limit of the Nb content is preferably 0.090%, more preferably 0.070%, still more preferably 0.050%, still more preferably 0.030%, still more preferably 0.030%. 020%.
  • V 0-0.100%
  • Vanadium (V) is an optional element and may not be contained. That is, the V content may be 0%. When V is included, ie when the V content is greater than 0%, V forms carbides, nitrides and/or carbonitrides. This enhances the strength and workability of the steel pipe 1 . If even a small amount of V is contained, the above effect can be obtained to some extent. On the other hand, if the V content exceeds 0.100%, the ductility of the steel pipe 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the V content is 0-0.100%.
  • the lower limit of the V content is preferably 0.001%, more preferably 0.005%, still more preferably 0.010%, still more preferably 0.015%, still more preferably 0.01%. 020%.
  • the upper limit of the V content is preferably 0.090%, more preferably 0.080%, still more preferably 0.070%, still more preferably 0.060%, still more preferably 0.060%. 050%, more preferably 0.040%.
  • the chemical composition of the base material 2 of the steel pipe 1 according to this embodiment may further contain B instead of part of Fe.
  • B 0 to 0.0050% Boron (B) is an optional element and may not be contained. That is, the B content may be 0%. When B is contained, that is, when the B content is over 0%, B enhances the hardenability of the steel. If even a small amount of B is contained, the above effect can be obtained to some extent. On the other hand, if the B content exceeds 0.0050%, the steel pipe 1 is likely to become embrittled even if the contents of other elements are within the ranges of the present embodiment. Therefore, the B content is 0-0.0050%.
  • the lower limit of the B content is preferably 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005%, still more preferably 0.0005%. 0010%.
  • the upper limit of the B content is preferably 0.0040%, more preferably 0.0030%, still more preferably 0.0020%.
  • the chemical composition of the base material 2 of the steel pipe 1 according to this embodiment may further contain Ca instead of part of Fe.
  • Ca 0-0.0050% Calcium (Ca) is an optional element and may not be contained. That is, the Ca content may be 0%. When Ca is contained, that is, when the Ca content is over 0%, Ca enhances the hot workability of the steel. If even a little Ca is contained, the above effect can be obtained to some extent. On the other hand, if the Ca content exceeds 0.0050%, the toughness of the steel pipe 1 is lowered even if the contents of other elements are within the range of the present embodiment. Therefore, the Ca content is 0-0.0050%.
  • the lower limit of the Ca content is preferably 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005%, still more preferably 0.0005%. 0010%, more preferably 0.0015%.
  • the upper limit of the Ca content is preferably 0.0040%, more preferably 0.0030%, still more preferably 0.0025%.
  • the chemical composition of the base material 2 of the steel pipe 1 of this embodiment can be measured by a known component analysis method.
  • a steel pipe 1 is cut into lengths of 10 cm in the axial direction of the steel pipe 1 .
  • the oxide film 3 on the outer surface 4 and the inner surface 5 of the cut steel pipe 1 is removed by cutting.
  • the steel pipe 1 from which the oxide film 3 has been removed is finely pulverized and dissolved in acid to obtain a solution.
  • ICP-AES Inductively Coupled Plasma Atomic Emission Spectrometry
  • the C content and S content are obtained by a well-known high-frequency combustion method (combustion-infrared absorption method).
  • the N content is determined using the well-known inert gas fusion-thermal conductivity method.
  • each element content based on the significant digits defined in this embodiment, rounded off the measured numerical value, the numerical value up to the minimum digit of each element content defined in this embodiment do.
  • the C content of the steel pipe 1 of the present embodiment is specified by a numerical value up to the second decimal place. Therefore, the C content is a numerical value to the second decimal place obtained by rounding the measured numerical value to the third decimal place.
  • the contents of elements other than the C content of the steel pipe 1 of the present embodiment are obtained by rounding the measured values to the minimum digit specified in the present embodiment.
  • the value is taken as the elemental content. Rounding means rounding down if the fraction is less than 5, and rounding up if the fraction is 5 or more.
  • the base material 2 of the steel pipe 1 of this embodiment has a microstructure composed of 20% to 60% ferrite and 40% to 80% pearlite in area ratio.
  • a vehicle component can be manufactured by quenching and tempering the steel pipe 1 after cold bending. Therefore, the steel pipe 1 is required to have excellent workability.
  • the base material 2 has a microstructure consisting of 20% to 60% ferrite and 40% to 80% pearlite in area ratio, the steel pipe 1 has excellent workability.
  • the lower limit of the area ratio of ferrite is preferably 25%, more preferably 30%, still more preferably 35%, still more preferably 40%.
  • the upper limit of the ferrite area ratio is preferably 55%, more preferably 50%, and still more preferably 45%.
  • the lower limit of the area ratio of pearlite is preferably 45%, more preferably 50%, and still more preferably 55%.
  • the upper limit of the area ratio of pearlite is preferably 75%, more preferably 70%, still more preferably 65%, still more preferably 60%.
  • the area ratios of ferrite and pearlite in the base material 2 of the steel pipe 1 are obtained by the following method. Three arbitrary points of the steel pipe 1 are cut to a length of 10 cm in the axial direction of the steel pipe 1 .
  • the oxide film 3 on the outer surface 4 and the inner surface 5 of the cut steel pipe 1 is removed by cutting.
  • the outer surface 4 or the inner surface 5 of the steel pipe 1 from which the oxide film 3 has been removed is defined as an observation surface.
  • the observation surface of the steel pipe 1 is mirror-polished. Etching is performed on the mirror-polished observation surface using 3% nitric acid alcohol (nital etchant). Among the etched observation surfaces, an observation field (200 ⁇ m ⁇ 200 ⁇ m) at a depth of 0.5 mm from the outer surface 4 or inner surface 5 of the steel pipe 1 is observed with a 500-fold optical microscope.
  • pearlite and ferrite can be easily distinguished by contrast. Ferrite is observed as white areas. Pearlite is observed as a phase with a lamellar structure that is less bright than ferrite. Based on the area of ferrite in the observation field of view and the total area of the observation field of view, the area ratio (%) of ferrite is obtained. Based on the pearlite area in the observation field of view and the total area of the observation field of view, the pearlite area ratio (%) is determined. Let the arithmetic average value of three places of a steel pipe be the area ratio of a ferrite, and the area ratio of a pearlite.
  • a steel pipe 1 of this embodiment has an oxide film 3 on a base material 2 .
  • the oxide film 3 has an X-ray diffraction peak intensity ratio of 70% or more when the sum of the X-ray diffraction peak intensities of Fe 3 O 4 , Fe 2 O 3 and FeO is 100%. 20% or more of Fe 2 O 3 , 10% or less of FeO, and the balance consists of impurities.
  • An oxide film 3 having the composition described above is formed on a steel pipe 1 before quenching. This increases the fatigue strength of the vehicle component.
  • the lower limit of the peak intensity ratio of Fe 3 O 4 is preferably 72%, more preferably 74%, still more preferably 75%.
  • the upper limit of the peak intensity ratio of Fe 3 O 4 is not particularly limited, it is, for example, 80%.
  • the upper limit of the peak intensity ratio of Fe 3 O 4 is preferably 78%, more preferably 76%, still more preferably 75%.
  • the lower limit of the peak intensity ratio of Fe 2 O 3 is preferably 21%, more preferably 22%, still more preferably 23%, still more preferably 25%.
  • the upper limit of the peak intensity ratio of Fe 2 O 3 is not particularly limited, it is, for example, 30%.
  • the upper limit of the peak intensity ratio of Fe 2 O 3 is preferably 29%, more preferably 28%, still more preferably 27%.
  • the lower limit of the FeO peak intensity ratio is not particularly limited, and may be 0%.
  • the upper limit of the peak intensity ratio of FeO is preferably 8%, more preferably 6%, still more preferably 4%, still more preferably 2%.
  • composition of the oxide film 3 of the steel pipe 1 is obtained by the following method.
  • X-ray diffraction measurement is performed on the surface of oxide film 3 to obtain an X-ray diffraction profile. Measurement is performed at three arbitrary points on the surface of oxide film 3 .
  • the measurement conditions for the X-ray diffraction measurement are as follows.
  • X-ray tube Cu-K ⁇ ray (assumed to be Cu-K ⁇ 1 ray by using a monochromator)
  • X-ray output 45kV, 200mA
  • Measurement range: 2 ⁇ 10 to 120°
  • Scan method Continuous scan speed: 2.0°/min
  • the X-ray diffraction peak intensities of Fe 3 O 4 , Fe 2 O 3 and FeO are obtained.
  • the sum of the X-ray diffraction peak intensities of Fe 3 O 4 , Fe 2 O 3 and FeO is taken as 100%.
  • the peak intensity ratio of Fe 3 O 4 , Fe 2 O 3 and FeO is determined from the sum of the peak intensities and the X-ray diffraction peak intensities of Fe 3 O 4 , Fe 2 O 3 and FeO.
  • the thickness of the oxide film 3 is less than 0.80 ⁇ m, the effect of suppressing contact between the surfaces 4 and 5 of the steel pipe 1 and oxygen cannot be obtained. On the other hand, if the thickness of the oxide film 3 exceeds 2.50 ⁇ m, the adhesion of the oxide film 3 is lowered, and the oxide film 3 is peeled off from the surfaces 4 and 5 of the steel pipe 1 . Therefore, the thickness of oxide film 3 is preferably 0.80 to 2.50 ⁇ m.
  • the lower limit of the thickness of oxide film 3 is more preferably 0.84 ⁇ m, more preferably 0.88 ⁇ m, still more preferably 1.00 ⁇ m, still more preferably 1.20 ⁇ m.
  • the upper limit of the thickness of the oxide film 3 is more preferably 2.40 ⁇ m, more preferably 2.30 ⁇ m, still more preferably 2.20 ⁇ m, still more preferably 2.00 ⁇ m, still more preferably 1.0 ⁇ m. 80 ⁇ m.
  • the thickness of the oxide film 3 of the steel pipe 1 is obtained by the following method.
  • a steel pipe 1 is cut perpendicular to the axial direction.
  • Scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDS) analysis is performed on the cut surface.
  • the oxide film 3 is identified from the contrast and the Fe and O concentrations.
  • the shortest radial distance of the steel pipe 1 is measured. Observation and measurement are performed at 30 arbitrary points on the steel pipe 1 .
  • the arithmetic average value of the thicknesses of the oxide film 3 at 30 locations is taken as the thickness of the oxide film 3 .
  • the lower limit of the standard deviation of the thickness of the oxide film 3 is preferably 0.01 ⁇ m, more preferably 0.03 ⁇ m, More preferably, it is 0.05 ⁇ m.
  • the upper limit of the thickness of oxide film 3 is more preferably 0.80 ⁇ m, more preferably 0.70 ⁇ m, still more preferably 0.60 ⁇ m, still more preferably 0.50 ⁇ m.
  • the thickness of the oxide film 3 is measured by the method using the SEM-EDS described above. Let the standard deviation of the thickness of 30 points be the standard deviation of the thickness of the oxide film 3 . In the present disclosure, standard deviation is sample standard deviation (JIS Z8101-1).
  • An example of the method for manufacturing the steel pipe 1 of this embodiment includes the following steps.
  • (Step 1) Steel plate preparation step (Step 2) Low temperature heat treatment step (Step 3) Pipe making step
  • Step 2) Steel plate preparation step (Step 2) Low temperature heat treatment step (Step 3) Pipe making step
  • Step 1 Steel plate preparation step
  • a steel plate for manufacturing the steel pipe 1 of the present embodiment is prepared.
  • the steel plate may be obtained from a third party or manufactured.
  • molten steel is produced in which the content of each element in the chemical composition is within the range of the present embodiment.
  • a refining method is not particularly limited, and a well-known method may be used.
  • molten steel a material is manufactured by a well-known casting method.
  • an ingot may be manufactured by an ingot casting method using molten steel.
  • a raw material (ingot or bloom) is manufactured by the above method. The raw material is heated and subjected to rough rolling and finish rolling by well-known methods.
  • a hot-rolled steel sheet is manufactured.
  • the coiling temperature of the hot-rolled steel sheet is, for example, over 600 to 700°C.
  • Step 2 Low temperature heat treatment step
  • the hot-rolled steel sheet is subjected to low-temperature heat treatment under the following conditions.
  • (Manufacturing condition 1) Heat treatment temperature: 450-600°C (Manufacturing condition 2) Heat treatment time: 0.5 to 3.0 minutes
  • the manufactured hot-rolled steel sheet is in a state of being wound into a coil.
  • the steel sheet is unwound and subjected to low-temperature heat treatment while the surface of the steel sheet is exposed to the atmosphere.
  • the low temperature heat treatment conditions are as described above.
  • the surface of the steel sheet has an X-ray diffraction peak intensity ratio of 70% or more Fe 3 O 4 , 20% or more Fe 2 O 3 , 10% or less FeO, and the balance is impurities, and the thickness is An oxide film 3 having a thickness of 0.80 to 2.50 ⁇ m and a standard deviation of thickness of 0.90 ⁇ m or less is formed. Formation of the oxide film described above increases the fatigue strength of the vehicle component.
  • Step 3 Electric resistance welded steel pipes are manufactured using hot-rolled steel sheets subjected to low-temperature heat treatment.
  • a forming roll is used to form a hot-rolled steel sheet into a cylindrical blank pipe (open pipe).
  • the formed blank tube is formed so that the width direction of the hot-rolled steel sheet coincides with the circumferential direction of the blank tube.
  • Electric resistance welding is performed on butt portions extending in the longitudinal direction of the tube.
  • An electric resistance welded steel pipe is manufactured by the pipe manufacturing process described above.
  • the steel pipe 1 of the present embodiment can be manufactured through the above steps.
  • the method for manufacturing the steel pipe 1 of this embodiment may further include other steps.
  • Another process is, for example, a diameter reduction rolling process.
  • diameter-reducing rolling step for example, diameter-reducing rolling may be performed under known conditions.
  • the steel pipe 1 of the present disclosure is suitable as a stabilizer steel pipe.
  • the use of the steel pipe 1 of the present disclosure is not limited to steel pipes for stabilizers.
  • the steel pipe 1 of the present disclosure can be used for inner tie rods, drive shafts and upper arms, for example.
  • the steel pipe 1 of this embodiment has the following features.
  • the content of each element in the chemical composition of the base material 2 is within the range shown in this specification.
  • the microstructure of the base material 2 consists of 20% to 60% ferrite and 40% to 80% pearlite in area ratio.
  • (Feature 3) When the sum of the X-ray diffraction peak intensities of Fe 3 O 4 , Fe 2 O 3 and FeO on the base material 2 is 100%, the X-ray diffraction peak intensity ratio is 70% or more.
  • An oxide film 3 composed of Fe 3 O 4 , 20% or more Fe 2 O 3 , 10% or less FeO, and the balance of impurities is disposed.
  • the oxide film 3 has a thickness of 0.80 to 2.50 ⁇ m.
  • the standard deviation of the thickness of the oxide film 3 is 0.90 ⁇ m or less.
  • the steel pipe 1 of this embodiment having features 1 to 5 can be used to manufacture vehicle parts with excellent fatigue strength.
  • FIG. 2 is a perspective view of an end portion of the vehicle component of this embodiment.
  • vehicle component 10 includes hollow base material 20 and oxide film 30 on base material 20 .
  • Vehicle component 10 includes an outer surface 40 and an inner surface 50 .
  • the oxide film 30 may be formed only on the outer surface 40 of the vehicle component 10, may be formed only on the inner surface 50, or may be formed on both the outer surface 40 and the inner surface 50.
  • the decarburized layer on outer surface 40 of vehicle component 10 can be removed by shot peening, for example. On the other hand, the decarburized layer on the inner surface 50 of the vehicle component 10 may be difficult to remove. Therefore, vehicle component 10 preferably comprises oxide layer 30 at least on inner surface 50 .
  • the vehicle parts 10 are, for example, stabilizers, inner tie rods, drive shafts, and upper arms.
  • the vehicle component 10 of this embodiment has the following features.
  • the content of each element in the chemical composition of the base material 20 is within the range shown in this specification.
  • the microstructure of the base material 20 consists of tempered martensite.
  • the X-ray diffraction peak intensity ratio is 80% or more.
  • An oxide film 30 composed of Fe 3 O 4 , 15% or less FeO, 5% or less Fe 2 O 3 , and the balance being impurities is disposed.
  • the thickness of the oxide film 30 is 3.50 ⁇ m or less. Characteristics 6 to 9 will be described below.
  • the chemical composition of the base material 20 of the vehicle component 10 of this embodiment contains the following elements.
  • C 0.23-0.50% Carbon (C) enhances the hardenability of steel. C further dissolves in steel. Thereby, C increases the strength of steel. If the C content is less than 0.23%, the above effect cannot be sufficiently obtained even if the content of other elements is within the range of the present embodiment. On the other hand, if the C content exceeds 0.50%, the hot workability of the steel deteriorates even if the content of other elements is within the range of the present embodiment. If the C content exceeds 0.50%, the toughness of the vehicle component 10 after quenching is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the C content is 0.23-0.50%.
  • the lower limit of the C content is preferably 0.25%, more preferably 0.27%, still more preferably 0.30%, still more preferably 0.33%, still more preferably 0.33%. It is 35%, more preferably 0.38%, and still more preferably 0.40%.
  • the upper limit of the C content is preferably 0.48%, more preferably 0.46%, still more preferably 0.44%, still more preferably 0.42%, still more preferably 0.42%. 40%, more preferably 0.38%.
  • Si 0.01-0.50% Silicon (Si) deoxidizes steel. Si also forms a solid solution in steel to increase the strength of the steel. If the Si content is less than 0.01%, the above effect cannot be sufficiently obtained even if the content of other elements is within the range of the present embodiment. On the other hand, if the Si content exceeds 0.50%, the ductility and toughness of the vehicle component 10 are lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Si content is 0.01-0.50%.
  • the lower limit of the Si content is preferably 0.05%, more preferably 0.10%, still more preferably 0.15%, still more preferably 0.20%, still more preferably 0 .25%.
  • the upper limit of the Si content is preferably 0.45%, more preferably 0.40%, still more preferably 0.35%, still more preferably 0.30%.
  • Mn 0.50-2.50%
  • Manganese (Mn) increases the hardenability of steel. Mn further dissolves in steel. Thereby, Mn increases the strength of steel. If the Mn content is less than 0.50%, the above effect cannot be sufficiently obtained even if the content of other elements is within the range of the present embodiment. On the other hand, if the Mn content exceeds 2.50%, the toughness and ductility of the vehicle component 10 after quenching decrease even if the contents of other elements are within the ranges of the present embodiment. Therefore, the Mn content is 0.50-2.50%.
  • the lower limit of the Mn content is preferably 0.60%, more preferably 0.70%, still more preferably 0.75%, still more preferably 0.80%, still more preferably 0.80%.
  • the upper limit of the Mn content is preferably 2.40%, more preferably 2.30%, still more preferably 2.20%, still more preferably 2.10%, still more preferably 2.10%. 00%, more preferably 1.90%, more preferably 1.80%, still more preferably 1.70%, still more preferably 1.60%, still more preferably 1.0%. 50%.
  • P 0.050% or less Phosphorus (P) is an impurity. Therefore, the P content is over 0%. If the P content exceeds 0.050%, P segregates at the grain boundaries and reduces the ductility of the steel even if the content of other elements is within the range of the present embodiment. Therefore, the P content is 0.050% or less. The lower the P content, the better. However, drastic reduction of the P content greatly increases manufacturing costs. Therefore, when considering industrial production, the lower limit of the P content is preferably 0.001%, more preferably 0.002%, still more preferably 0.003%, still more preferably 0.005 %. The upper limit of the P content is preferably 0.040%, more preferably 0.030%, still more preferably 0.020%, still more preferably 0.010%.
  • S 0.0100% or less Sulfur (S) is an impurity. Therefore, the S content is over 0%. If the S content exceeds 0.0100%, the hot workability, toughness and fatigue strength of the steel are lowered even if the contents of other elements are within the range of the present embodiment. Therefore, the S content is 0.0100% or less. The lower the S content, the better. However, drastic reduction of the S content greatly increases manufacturing costs. Therefore, when considering industrial production, the lower limit of the S content is preferably 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005 %. The upper limit of the S content is preferably 0.0080%, more preferably 0.0070%, still more preferably 0.0060%, still more preferably 0.0050%, still more preferably 0.0050%. 0040%.
  • N 0.0100% or less Nitrogen (N) is an impurity. Therefore, the N content is over 0%. If the N content exceeds 0.0100%, the toughness of the steel is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the N content is 0.0100% or less.
  • N forms nitrides and/or carbonitrides to increase the strength of steel.
  • the preferred lower limit of the N content is 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005%, still more preferably 0.0010 %, more preferably 0.0020%, more preferably 0.0030%.
  • the upper limit of the N content is preferably 0.0080%, more preferably 0.0070%, still more preferably 0.0060%, still more preferably 0.0050%, still more preferably 0.0050%. 0040%.
  • Oxygen (O) is an impurity. Therefore, the O content is over 0%. If the O content exceeds 0.0100%, the toughness of the steel is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the O content is 0.0100% or less. The lower the O content, the better. However, drastic reduction of O content greatly increases manufacturing cost. Therefore, when considering industrial production, the preferred lower limit of the O content is 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005% is. The upper limit of the O content is preferably 0.0080%, more preferably 0.0070%, still more preferably 0.0060%, still more preferably 0.0050%, still more preferably 0.0050%. 0040%, more preferably 0.0030%.
  • the rest of the chemical composition of the base material 20 of the vehicle component 10 of the present embodiment consists of Fe and impurities.
  • the impurities in the chemical composition are those that are mixed from ore, scrap, or the manufacturing environment as raw materials when the vehicle component 10 is industrially manufactured. It means that it is permissible within a range that does not have an adverse effect.
  • the chemical composition of the base material 20 of the vehicle component 10 according to the present embodiment may further contain Al instead of part of Fe.
  • Al is an optional element and may not be contained. That is, the Al content may be 0%.
  • Al deoxidizes the steel.
  • Al further combines with nitrogen (N) to produce AlN.
  • AlN suppresses coarsening of crystal grains during quenching. If even a small amount of Al is contained, the above effect can be obtained to some extent.
  • Al content exceeds 0.080%, even if the content of other elements is within the range of the present embodiment, Al combines with oxygen (O) to excessively generate inclusions. This reduces the fatigue strength of the vehicle component 10 . Therefore, the Al content is 0-0.080%.
  • the lower limit of the Al content is preferably more than 0%, more preferably 0.001%, still more preferably 0.005%, still more preferably 0.010%, still more preferably 0.015 %.
  • the upper limit of the Al content is preferably 0.070%, more preferably 0.060%, still more preferably 0.050%, still more preferably 0.040%, still more preferably 0.040%. 030%.
  • the chemical composition of the base material 20 of the vehicle component 10 according to the present embodiment may further contain one or more elements selected from the group consisting of Cr, Mo, Ni and Cu instead of part of Fe. All of these elements are optional elements and may not be contained. When included, both of these elements increase the strength of vehicle component 10 .
  • Chromium (Cr) is an optional element and may not be contained. That is, the Cr content may be 0%. When Cr is contained, that is, when the Cr content is over 0%, Cr enhances the strength of the vehicle component 10 . If even a little Cr is contained, the above effect can be obtained to some extent. On the other hand, if the Cr content exceeds 1.50%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Cr content is 0-1.50%.
  • the lower limit of the Cr content is preferably 0.01%, more preferably 0.05%, still more preferably 0.10%, still more preferably 0.20%, still more preferably 0.20%. 30%.
  • the upper limit of the Cr content is preferably 1.20%, more preferably 1.00%, still more preferably 0.80%, still more preferably 0.60%, still more preferably 0.60%. 40%.
  • Mo Molybdenum
  • Mo is an optional element and may not be contained. That is, the Mo content may be 0%. When Mo is contained, that is, when the Mo content is over 0%, Mo enhances the strength of the vehicle component 10 . If even a little Mo is contained, the above effect can be obtained to some extent. On the other hand, if the Mo content exceeds 1.00%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Mo content is 0-1.00%.
  • the lower limit of the Mo content is preferably 0.01%, more preferably 0.02%, still more preferably 0.03%, still more preferably 0.04%, still more preferably 0.04%. 05%.
  • the upper limit of the Mo content is preferably 0.80%, more preferably 0.60%, still more preferably 0.40%, still more preferably 0.20%, still more preferably 0.20%. 10%.
  • Nickel (Ni) is an optional element and may not be contained. That is, the Ni content may be 0%. When Ni is contained, that is, when the Ni content is over 0%, Ni enhances the strength of the vehicle component 10 . If Ni is contained even in a small amount, the above effect can be obtained to some extent. On the other hand, if the Ni content exceeds 1.00%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Ni content is 0-1.00%.
  • the lower limit of the Ni content is preferably 0.01%, more preferably 0.02%, still more preferably 0.05%, still more preferably 0.10%, still more preferably 0.05%. 15%.
  • the upper limit of the Ni content is preferably 0.80%, more preferably 0.60%, still more preferably 0.40%, still more preferably 0.20%.
  • Cu Copper (Cu) is an optional element and may not be contained. That is, the Cu content may be 0%. When Cu is contained, that is, when the Cu content is over 0%, Cu enhances the strength of the vehicle component 10 . If even a small amount of Cu is contained, the above effects can be obtained to some extent. On the other hand, if the Cu content exceeds 1.00%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Cu content is 0-1.00%.
  • the lower limit of the Cu content is preferably 0.01%, more preferably 0.02%, still more preferably 0.03%, still more preferably 0.04%, still more preferably 0.04%. 05%.
  • the upper limit of the Cu content is preferably 0.80%, more preferably 0.60%, still more preferably 0.40%, still more preferably 0.20%.
  • the chemical composition of the base material 20 of the vehicle component 10 according to this embodiment may further contain one or more elements selected from the group consisting of Ti, Nb and V instead of part of Fe. All of these elements are optional elements and may not be contained. Both of these elements, when included, enhance the strength and workability of the vehicle component 10 .
  • Titanium (Ti) is an optional element and may not be contained. That is, the Ti content may be 0%. When Ti is contained, ie when the Ti content is greater than 0%, Ti forms carbides, nitrides and/or carbonitrides. This enhances the strength and workability of the vehicle component 10 . If even a small amount of Ti is contained, the above effect can be obtained to some extent. On the other hand, if the Ti content exceeds 0.100%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Ti content is 0-0.100%.
  • the lower limit of the Ti content is preferably 0.001%, more preferably 0.005%, still more preferably 0.010%, still more preferably 0.020%, still more preferably 0.020%. 030%.
  • the upper limit of the Ti content is preferably 0.090%, more preferably 0.080%, still more preferably 0.070%, still more preferably 0.060%.
  • Niobium (Nb) is an optional element and may not be contained. That is, the Nb content may be 0%. If Nb is included, ie if the Nb content is greater than 0%, Nb forms carbides, nitrides and/or carbonitrides. This enhances the strength and workability of the vehicle component 10 . If even a small amount of Nb is contained, the above effect can be obtained to some extent. On the other hand, if the Nb content exceeds 0.100%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Nb content is 0-0.100%.
  • the lower limit of the Nb content is preferably 0.001%, more preferably 0.002%, still more preferably 0.005%, still more preferably 0.010%, still more preferably 0.01%. 015%.
  • the upper limit of the Nb content is preferably 0.090%, more preferably 0.070%, still more preferably 0.050%, still more preferably 0.030%, still more preferably 0.030%. 020%.
  • V 0-0.100%
  • Vanadium (V) is an optional element and may not be contained. That is, the V content may be 0%. When V is included, ie when the V content is greater than 0%, V forms carbides, nitrides and/or carbonitrides. This enhances the strength and workability of the vehicle component 10 . If even a small amount of V is contained, the above effect can be obtained to some extent. On the other hand, if the V content exceeds 0.100%, the ductility of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the V content is 0-0.100%.
  • the lower limit of the V content is preferably 0.001%, more preferably 0.005%, still more preferably 0.010%, still more preferably 0.015%, still more preferably 0.01%. 020%.
  • the upper limit of the V content is preferably 0.090%, more preferably 0.080%, still more preferably 0.070%, still more preferably 0.060%, still more preferably 0.060%. 050%, more preferably 0.040%.
  • the chemical composition of the base material 20 of the vehicle component 10 according to this embodiment may further contain B instead of part of Fe.
  • B 0 to 0.0050% Boron (B) is an optional element and may not be contained. That is, the B content may be 0%. When B is contained, that is, when the B content is over 0%, B enhances the hardenability of the steel. If even a small amount of B is contained, the above effect can be obtained to some extent. On the other hand, if the B content exceeds 0.0050%, the vehicle component 10 tends to become embrittled even if the content of other elements is within the range of the present embodiment. Therefore, the B content is 0-0.0050%.
  • the lower limit of the B content is preferably 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005%, still more preferably 0.0005%. 0010%.
  • the upper limit of the B content is preferably 0.0040%, more preferably 0.0030%, still more preferably 0.0020%.
  • the chemical composition of the base material 20 of the vehicle component 10 according to this embodiment may further contain Ca instead of part of Fe.
  • Ca 0-0.0050% Calcium (Ca) is an optional element and may not be contained. That is, the Ca content may be 0%. When Ca is contained, that is, when the Ca content is over 0%, Ca enhances the hot workability of the steel. If even a little Ca is contained, the above effect can be obtained to some extent. On the other hand, if the Ca content exceeds 0.0050%, the toughness of the vehicle component 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Ca content is 0-0.0050%.
  • the lower limit of the Ca content is preferably 0.0001%, more preferably 0.0002%, still more preferably 0.0003%, still more preferably 0.0005%, still more preferably 0.0005%. 0010%, more preferably 0.0015%.
  • the upper limit of the Ca content is preferably 0.0040%, more preferably 0.0030%, still more preferably 0.0025%.
  • the chemical composition of the base material 20 of the vehicle component 10 of this embodiment is determined by the same method as the chemical composition of the base material 2 of the steel pipe 1 .
  • the vehicle component 10 is cut into lengths of 10 cm in the axial direction of the vehicle component 10 .
  • the oxide film 30 on the outer surface 40 and the inner surface 50 of the cut vehicle component 10 is removed by cutting.
  • the vehicle component 10 from which the oxide film 30 has been removed is finely pulverized and dissolved in acid to obtain a solution.
  • ICP-AES is performed on the solution to perform elemental analysis for chemical composition.
  • the C content and S content are obtained by a well-known high-frequency combustion method (combustion-infrared absorption method).
  • the N content is determined using the well-known inert gas fusion-thermal conductivity method.
  • the content of each element is defined in this embodiment by rounding off the fractions of the measured numerical values based on the significant digits defined in this embodiment. It is a numerical value to the lowest digit of each element content.
  • the base material 20 of the vehicle component 10 of this embodiment has a microstructure composed of tempered martensite.
  • the area ratio of phases other than tempered martensite is so small that it can be ignored.
  • the microstructure of the base material 20 of the vehicle component 10 is observed and identified by the observation method described in [Method for measuring area ratio of ferrite and pearlite] above.
  • the vehicle component 10 of this embodiment has an oxide film 30 on the base material 20 .
  • the oxide film 30 is Fe 3 O 4 having an X-ray diffraction peak intensity ratio of 80% or more when the sum of the X-ray diffraction peak intensities of Fe 3 O 4 , FeO, and Fe 2 O 3 is 100%. , up to 15% FeO, up to 5% Fe 2 O 3 , and the balance consisting of impurities.
  • the lower limit of the peak intensity ratio of Fe 3 O 4 is preferably 81%, more preferably 85%, still more preferably 90%.
  • the upper limit of the peak intensity ratio of Fe 3 O 4 may be 100%.
  • the upper limit of the peak intensity ratio of Fe 3 O 4 is preferably 99%, more preferably 98%, still more preferably 97%, still more preferably 96%.
  • the lower limit of the FeO peak intensity ratio may be 0%.
  • the lower limit of the FeO peak intensity ratio is preferably 1%, more preferably 2%, and still more preferably 3%.
  • the upper limit of the peak intensity ratio of FeO is preferably 14%, more preferably 13%, still more preferably 12%, still more preferably 11%.
  • the lower limit of the peak intensity ratio of Fe 2 O 3 may be 0%.
  • the lower limit of the peak intensity ratio of Fe 2 O 3 is preferably 0.1%, more preferably 0.2%.
  • the upper limit of the peak intensity ratio of Fe 2 O 3 is preferably 4%, more preferably 3%.
  • composition of the oxide film 30 of the vehicle component 10 is obtained by the following method.
  • X-ray diffraction measurement is performed on the surface of the oxide film 30 to obtain an X-ray diffraction profile.
  • the measurement is performed at three arbitrary points on the surface of the oxide film 30 .
  • the measurement conditions for the X-ray diffraction measurement are the same as those for the X-ray diffraction measurement of the oxide film 3 of the steel pipe 1 described above. From the obtained X-ray diffraction profile, the X-ray diffraction peak intensities of Fe 3 O 4 , FeO and Fe 2 O 3 are determined.
  • the sum of X-ray diffraction peak intensities of Fe 3 O 4 , FeO and Fe 2 O 3 is taken as 100%.
  • the peak intensity ratio of Fe 3 O 4 , FeO and Fe 2 O 3 is determined from the sum of the peak intensities and the X-ray diffraction peak intensities of Fe 3 O 4 , FeO and Fe 2 O 3 .
  • oxide film 30 has a thickness of 3.50 ⁇ m or less.
  • the lower limit of the thickness of oxide film 30 is not particularly limited, it is, for example, 0.01 ⁇ m.
  • the lower limit of the thickness of the oxide film 30 is preferably 0.50 ⁇ m, more preferably 1.00 ⁇ m, still more preferably 1.50 ⁇ m, still more preferably 2.00 ⁇ m.
  • the upper limit of the thickness of the oxide film 30 is more preferably 3.40 ⁇ m, more preferably 3.20 ⁇ m, still more preferably 3.00 ⁇ m, still more preferably 2.90 ⁇ m, still more preferably 2.90 ⁇ m. 80 ⁇ m, more preferably 2.50 ⁇ m.
  • the method for measuring the thickness of the oxide film 30 of the vehicle component 10 is the same as the method for measuring the thickness of the oxide film 3 of the steel pipe 1 . Observation and measurement are performed at any three locations of the vehicle component 10 .
  • An example of a method for manufacturing the vehicle component 10 of this embodiment includes the following steps.
  • (Step 4) Steel pipe preparation step (Step 5) Bending step (Step 6) Quenching step (Step 7) Tempering step
  • Step 4 Steel pipe preparation step
  • Step 5 Bending step
  • Step 6 Quenching step
  • Step 7 Tempering step
  • Step 4 Steel pipe preparation step
  • a steel pipe for manufacturing the vehicle component 10 of the present embodiment is prepared.
  • the steel pipe to be prepared may be a seamless steel pipe or an electric resistance welded steel pipe.
  • the steel pipe may be obtained from a third party or manufactured. When manufacturing a steel pipe, it may be manufactured by the method for manufacturing the steel pipe 1 of the present embodiment described above.
  • Step 6 Quenching Step
  • the cooling method is a well-known cooling method.
  • (Manufacturing condition 3) Quenching temperature: Ac 3 +50°C or higher and 1150°C or lower (manufacturing condition 4) Holding time: 10 seconds or longer
  • Step 7) Tempering step In the tempering step, the quenched steel pipe is tempered under the following conditions. (Manufacturing condition 5) Tempering temperature: 150-350°C (Manufacturing condition 6) Holding time: 10 minutes or longer
  • the vehicle component 10 of the present embodiment can be manufactured through the above steps.
  • the method for manufacturing the vehicle component 10 of this embodiment may further include other steps.
  • Another process is, for example, a surface treatment process.
  • the surface treatment step for example, shot peening may be performed on the outer surface 40 of the obtained vehicle component 10 .
  • the outer surface 40 of the obtained vehicle component 10 may be subjected to dustproof treatment.
  • the vehicle component 10 of the present disclosure is suitable as a stabilizer.
  • the application of the vehicle component 10 of the present disclosure is not limited to stabilizers.
  • the vehicle component 10 of the present disclosure can be used for inner tie rods, drive shafts, and upper arms, for example.
  • the vehicle component 10 of this embodiment has the following features.
  • the content of each element in the chemical composition of the base material 20 is within the range shown in this specification.
  • the microstructure of the base material 20 consists of tempered martensite.
  • the X-ray diffraction peak intensity ratio is 90% or more.
  • An oxide layer 30 consisting of Fe 3 O 4 , less than 10% FeO, less than 5% Fe 2 O 3 and the balance of impurities is disposed.
  • the thickness of the oxide film 30 is 3.50 ⁇ m or less.
  • the vehicle component 10 of this embodiment having features 6 to 9 is excellent in fatigue strength.
  • the effects of the steel pipe 1 and the vehicle component 10 of this embodiment will be explained more specifically by way of examples.
  • the conditions in the following examples are examples of conditions adopted for confirming the feasibility and effects of the steel pipe 1 and the vehicle component 10 of this embodiment. Therefore, the steel pipe 1 and the vehicle component 10 of this embodiment are not limited to this one condition example.
  • “-" in Table 1 means that the content of the corresponding element is 0% in significant figures (values up to the least significant digit) specified in the embodiment. In other words, it means that the corresponding element content is 0% when rounded off to the specified significant digits (values up to the least significant digit) in the above embodiment.
  • the Cr content specified in this embodiment is specified by a numerical value up to the second decimal place. Thus, for test number 1 in Table 1, this means that the measured Cr content was 0% when rounded to the third decimal place.
  • a bloom was prepared from the molten steel of each test number.
  • the bloom was subjected to rough rolling and finish rolling to prepare a steel plate having a length of 1000 cm, a width of 300 cm and a thickness of 4 mm.
  • the steel sheets of each test number were subjected to low-temperature heat treatment at the heat treatment temperature and heat treatment time shown in Table 2 using a heat treatment furnace in an air atmosphere.
  • the thickness of the oxide film formed on the steel sheet before quenching after low-temperature heat treatment and its standard deviation are measured according to the above [Method for measuring thickness of oxide film] and [Method for measuring standard deviation of thickness of oxide film]. measured based on Observation and measurement were performed on three steel plates for each test number. The arithmetic mean value of the oxide film thicknesses of the three steel sheets was taken as the oxide film thickness for each test number. Table 2 shows the results. The standard deviation of the thickness of the oxide film of the three steel sheets used for the measurement was taken as the standard deviation of the thickness of the oxide film. Table 2 shows the results.
  • the steel sheets of each test number were quenched by holding at 850°C for 15 minutes and then quenching.
  • the steel plate after quenching was tempered at 200° C. for 60 minutes.
  • the microstructure of the base material of the steel sheet of each test number was observed and identified under the observation conditions described in the above [Measuring method of area ratio of ferrite and pearlite].
  • the base metals of the steel sheets of all test numbers had a microstructure composed of tempered martensite.
  • FIG. 3 is a front view of a torsional fatigue test piece.
  • FIG. 4 is a longitudinal side view of the torsional fatigue test piece.
  • the torsional fatigue test piece had a groove a with a depth of 0.1 mm, which simulated the inner surface of a steel pipe, in the central portion in the width direction of the surface.
  • a torsional fatigue test was performed in the air at a set stress of 400 MPa, and the number of times until the torsional fatigue test piece fractured was measured. Table 2 shows the results.
  • test number 13 the oxide film before quenching was too thick. Therefore, in test number 13, the oxide film after quenching was too thick. As a result, in Test No. 13, excellent fatigue strength was not obtained.
  • test number 14 the oxide film before quenching was too thin. Therefore, in test number 14, the oxide film after quenching was too thick. As a result, in Test No. 14, excellent fatigue strength was not obtained.
  • test number 15 the standard deviation of the thickness of the oxide film before quenching was too large. Therefore, in test number 15, the oxide film after quenching was too thick. As a result, in Test No. 15, excellent fatigue strength was not obtained.
  • test Nos. 16, 17 and 20 the composition of the oxide film before quenching was inappropriate, the oxide film was too thick, and the standard deviation of the thickness was too large. Therefore, in test numbers 16, 17 and 20, the composition of the oxide film after quenching was inappropriate and the oxide film was too thick. As a result, in test numbers 16, 17 and 20, excellent fatigue strength was not obtained.
  • test numbers 18 and 19 the composition of the oxide film before quenching was inappropriate, and the oxide film was too thin. Therefore, in test numbers 18 and 19, the oxide film after quenching was too thick. As a result, in test numbers 18 and 19, excellent fatigue strength was not obtained.
  • test number 21 the C content of the base material was too low. As a result, in Test No. 21, excellent fatigue strength was not obtained.
  • test number 22 the C content in the base material was too high. As a result, in Test No. 22, excellent fatigue strength was not obtained.

Landscapes

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

Abstract

La présente invention concerne : un composant pour véhicules, le composant ayant une excellente résistance à la fatigue ; un tuyau en acier qui permet la production du composant pour véhicules ayant une excellente résistance à la fatigue ; un procédé de production du tuyau en acier ; et un procédé de production du composant pour véhicules. Un tuyau en acier selon la présente divulgation est pourvu d'un matériau de base et d'un film de revêtement d'oxyde qui est présent sur le matériau de base. Le matériau de base a une composition chimique qui contient, en % en masse, de 0,23 % à 0,50 % de C, de 0,01 % à 0,50 % de Si, de 0,50 % à 2,50 % de Mn, une quantité inférieure ou égale à 0,050 % de P, une quantité inférieure ou égale à 0,0100 % de S, une quantité inférieure ou égale à 0,0100 % de N et une quantité inférieure ou égale à 0,0100 % de O, le reste étant constitué de Fe et d'impuretés ; et le matériau de base a une microstructure qui est composée de 20 % à 60 % en surface de ferrite et de 40 % à 80 % en surface de perlite. Le film de revêtement d'oxyde comprend, en termes de rapport d'intensité maximale de diffraction des rayons X, une quantité supérieure ou égale à 70 % de Fe3O4, une quantité supérieure ou égale à 20 % de Fe2O3 et une quantité inférieure ou égale à 10 % de FeO, le reste étant constitué d'impuretés, si le total des intensités maximales de diffraction des rayons X de Fe3O4, Fe2O3 et FeO est pris comme 100 % ; et le film de revêtement d'oxyde a une épaisseur de 0,80 µm à 2,50 µm et un écart-type de l'épaisseur inférieur ou égale à 0,90 µm.
PCT/JP2022/006953 2022-02-21 2022-02-21 Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules WO2023157297A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP2022/006953 WO2023157297A1 (fr) 2022-02-21 2022-02-21 Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules
PCT/JP2023/006173 WO2023157975A1 (fr) 2022-02-21 2023-02-21 Tuyau en acier, élément pour véhicules, procédé de production de tuyau en acier et procédé de production d'élément pour véhicules

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/006953 WO2023157297A1 (fr) 2022-02-21 2022-02-21 Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules

Publications (1)

Publication Number Publication Date
WO2023157297A1 true WO2023157297A1 (fr) 2023-08-24

Family

ID=87578171

Family Applications (2)

Application Number Title Priority Date Filing Date
PCT/JP2022/006953 WO2023157297A1 (fr) 2022-02-21 2022-02-21 Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules
PCT/JP2023/006173 WO2023157975A1 (fr) 2022-02-21 2023-02-21 Tuyau en acier, élément pour véhicules, procédé de production de tuyau en acier et procédé de production d'élément pour véhicules

Family Applications After (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/006173 WO2023157975A1 (fr) 2022-02-21 2023-02-21 Tuyau en acier, élément pour véhicules, procédé de production de tuyau en acier et procédé de production d'élément pour véhicules

Country Status (1)

Country Link
WO (2) WO2023157297A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04268016A (ja) * 1991-02-20 1992-09-24 Kobe Steel Ltd 圧壊特性に優れたドアガードバー用高張力鋼板の製造方法
JP2013007105A (ja) * 2011-06-24 2013-01-10 Kobe Steel Ltd 条鋼の製造方法
WO2018079398A1 (fr) * 2016-10-24 2018-05-03 Ｊｆｅスチール株式会社 Tuyau en acier soudé par résistance électrique destiné à un stabilisateur creux mince à haute résistance et son procédé de fabrication
JP2019183267A (ja) * 2018-04-03 2019-10-24 Ｊｆｅスチール株式会社 スケール密着性に優れた熱延鋼板およびその製造方法
WO2020129337A1 (fr) * 2018-12-19 2020-06-25 Ｊｆｅスチール株式会社 Tuyau en acier soudé par résistance électrique
KR20200076797A (ko) * 2018-12-19 2020-06-30 주식회사 포스코 강도 편차가 적은 열연 소둔 강판, 부재 및 이들의 제조방법

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005105341A (ja) * 2003-09-30 2005-04-21 Nisshin Steel Co Ltd 高温強度に優れたカラー受像管フレーム用角形電縫鋼管素材の製造方法
KR101665819B1 (ko) * 2014-12-24 2016-10-13 주식회사 포스코 열처리 강재, 내구특성이 우수한 초고강도 성형품 및 그 제조방법

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04268016A (ja) * 1991-02-20 1992-09-24 Kobe Steel Ltd 圧壊特性に優れたドアガードバー用高張力鋼板の製造方法
JP2013007105A (ja) * 2011-06-24 2013-01-10 Kobe Steel Ltd 条鋼の製造方法
WO2018079398A1 (fr) * 2016-10-24 2018-05-03 Ｊｆｅスチール株式会社 Tuyau en acier soudé par résistance électrique destiné à un stabilisateur creux mince à haute résistance et son procédé de fabrication
JP2019183267A (ja) * 2018-04-03 2019-10-24 Ｊｆｅスチール株式会社 スケール密着性に優れた熱延鋼板およびその製造方法
WO2020129337A1 (fr) * 2018-12-19 2020-06-25 Ｊｆｅスチール株式会社 Tuyau en acier soudé par résistance électrique
KR20200076797A (ko) * 2018-12-19 2020-06-30 주식회사 포스코 강도 편차가 적은 열연 소둔 강판, 부재 및 이들의 제조방법

Also Published As

Publication number Publication date
WO2023157975A1 (fr) 2023-08-24

Similar Documents

Publication Publication Date Title
RU2583194C2 (ru) Высокопрочный, гальванизированный погружением стальной лист и высокопрочный, подвергнутый легированию, гальванизированный погружением стальной лист, имеющие превосходную формуемость и низкую анизотропию материала, с пределом прочности на разрыв 980 мпа или более, и способ их получения
JP5353256B2 (ja) 中空部材およびその製造方法
CN109983145B (zh) 渗碳用钢板和渗碳用钢板的制造方法
JP5707671B2 (ja) 加工性と製造性に優れたＮｂ添加フェライト系ステンレス鋼板及びその製造方法
WO2013102986A1 (fr) Tôle d'acier laminée à chaud à forte teneur en carbone et son procédé de production
KR102124914B1 (ko) 오스테나이트계 스테인리스강
JP4220666B2 (ja) 成形性に優れたハイドロフォーム加工用高耐食鋼管およびその製造方法
JPWO2019198415A1 (ja) 浸炭処理が行われる部品用の鋼材
WO2015004902A1 (fr) Tôle d'acier laminée à chaud à teneur élevée en carbone et procédé de production de cette dernière
JP2015017283A (ja) 焼入れ性および加工性に優れる高炭素熱延鋼板およびその製造方法
WO2015146173A1 (fr) Tôle d'acier laminée à chaud à haute teneur en carbone et son procédé de production
CN108431246B (zh) 油井用不锈钢管的制造方法及油井用不锈钢管
WO2013102982A1 (fr) Tôle d'acier laminée à chaud à haute teneur en carbone avec une excellente trempabilité et une anisotropie minimale dans le plan et son procédé de production
WO2019131099A1 (fr) Tôle en acier laminée à chaud, et procédé de fabrication de celle-ci
CN115210400A (zh) 钢材及其制造方法、以及罐
JP2021127517A (ja) オーステナイト系ステンレス鋼材
CN111868281B (zh) 钢材
WO2023132339A1 (fr) MATÉRIAU D'ALLIAGE Fe-Cr-Ni
WO2023157297A1 (fr) Tuyau en acier, composant pour véhicules, procédé de production de tuyau en acier et procédé de production de composant pour véhicules
JP2021055141A (ja) フェライト系ステンレス鋼
CA3139909C (fr) Tuyau en acier soude par resistance electrique pour stabilisateur creux
JP5348458B2 (ja) Ｃｒ含有鋼管及びその製造方法
JP5565532B2 (ja) 高炭素熱延鋼板およびその製造方法
WO2018139671A1 (fr) Tuyau en acier pour pièces de dessous de caisse d'automobiles, et pièce de dessous de caisse d'automobiles
WO2018139672A1 (fr) Tuyau en acier pour composants de dessous de caisse d'automobiles et composant de dessous de caisse d'automobiles

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22927196

Country of ref document: EP

Kind code of ref document: A1