WO2017209180A1 - Acier cémenté et son procédé de fabrication et procédé de fabrication de composant d'engrenage - Google Patents

Acier cémenté et son procédé de fabrication et procédé de fabrication de composant d'engrenage Download PDF

Info

Publication number
WO2017209180A1
WO2017209180A1 PCT/JP2017/020258 JP2017020258W WO2017209180A1 WO 2017209180 A1 WO2017209180 A1 WO 2017209180A1 JP 2017020258 W JP2017020258 W JP 2017020258W WO 2017209180 A1 WO2017209180 A1 WO 2017209180A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
case
hardened steel
mass
component composition
Prior art date
Application number
PCT/JP2017/020258
Other languages
English (en)
Japanese (ja)
Inventor
佳祐 安藤
岩本　隆
冨田　邦和
長谷　和邦
西村　公宏
Original Assignee
Ｊｆｅスチール株式会社
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
Priority claimed from JP2016176921A external-priority patent/JP6460069B2/ja
Application filed by Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to KR1020187036498A priority Critical patent/KR102165228B1/ko
Priority to US16/305,519 priority patent/US11174543B2/en
Priority to CN201780032967.XA priority patent/CN109196134A/zh
Priority to CN202410111883.7A priority patent/CN117888030A/zh
Priority to EP17806731.0A priority patent/EP3467133B1/fr
Priority to MX2018014641A priority patent/MX2018014641A/es
Publication of WO2017209180A1 publication Critical patent/WO2017209180A1/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
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • 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
    • C21D9/32—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like
    • 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
    • C22C38/001—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
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/20—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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—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
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—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
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—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
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising
    • C23C8/22—Carburising of ferrous surfaces
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/80—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F17/00—Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25
    • 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

Definitions

  • the present invention relates to a case hardening steel used as a material for machine structural parts such as automobiles and various industrial machines, a manufacturing method thereof, and a manufacturing method of gear parts.
  • the present invention relates to a case hardening steel suitable as a material for machine structural parts having high rotational bending fatigue strength and surface pressure fatigue strength, and a method for producing the same.
  • gears used for mechanical structure parts for example, drive transmission parts such as automobiles
  • gears used for mechanical structure parts are required to be reduced in size as the vehicle weight is reduced due to energy saving. Therefore, improvement in durability is an issue.
  • the durability of gears is determined by the rotational bending fatigue failure of the tooth root and the contact pressure fatigue failure of the tooth surface, so far, with the aim of improving the rotational bending fatigue strength and the contact pressure fatigue strength, Various types of carburized case-hardened steels have been proposed that control the form of inclusions by adding elements and suppress the occurrence of abnormal carburization layers, or have imparted temper softening resistance, that is, suppress the decrease in hardness due to tempering. ing.
  • Patent Document 1 discloses that the grain boundary oxide layer on the surface layer after carburizing heat treatment is reduced by controlling the amount of Mn, Cr, Mo and Ni while reducing Si in steel to less than 0.15%.
  • MnS that reduces the occurrence of cracks and suppresses the formation of incompletely hardened layers, suppresses surface hardness reduction and increases fatigue strength, and further adds Ca to promote the generation and propagation of cracks.
  • a method for controlling the stretching of the film is disclosed.
  • Patent Document 2 discloses a method for improving temper softening resistance using a steel material to which Si is added as a raw material in a range of 0.25% to 1.50%.
  • the amount of Si, Mn and Cr contributing to the improvement of temper softening resistance is set to a predetermined value or more, and the amount of Si is increased by forming an alloy-deficient layer made of the element on the surface layer of the steel material. Even so, a method is disclosed in which the reduction in gas carburization is suppressed and the surface fatigue strength is increased.
  • low cycle fatigue is achieved by setting the projected core hardness determined from the core hardness after carburizing and quenching, the effective hardened layer depth, and the radius or half of the thickness of the damaged portion to a predetermined value or more.
  • a method of delaying the occurrence of microcracks at times is disclosed.
  • Patent Document 5 the amount of carbon and nitrogen on the surface at the time of carburizing or carbonitriding is controlled within a specific range to promote the formation of fine carbides in the surface layer portion, and the amount of retained austenite in the surface layer portion.
  • Patent Documents 1 to 5 described above have the following problems.
  • Patent Document 1 if Si is reduced to less than 0.15%, the grain boundary oxide layer and the incompletely hardened layer are reduced, so that the occurrence of cracks due to rotational bending fatigue at the gear teeth can be suppressed.
  • the temper softening resistance decreases and the occurrence of fracture shifts from the tooth base to the tooth surface.
  • temper softening due to frictional heat on the tooth surface cannot be suppressed, and the surface softens. Peeling damage, i.e., pitting, is likely to occur, and the surface pressure fatigue strength decreases.
  • Patent Document 2 Si is added in order to increase the temper softening resistance.
  • Si is added in order to increase the temper softening resistance.
  • more grain boundary oxide layers are formed by normal gas carburization, and this grain boundary oxide layer becomes a fatigue starting point.
  • the rotational bending fatigue strength decreases. Therefore, the carburizing process must be limited to plasma carburizing or vacuum carburizing in which no grain boundary oxide layer is formed.
  • these special carburizing treatments have the disadvantage of increasing manufacturing costs and are not suitable for mass production on an industrial scale.
  • Patent Document 3 the temper softening resistance is improved by adding Si, Mn and Cr.
  • Si, Mn and Cr the amount of retained austenite after carburizing and quenching increases, and the surface layer hardness decreases, thereby reducing the surface pressure fatigue strength and the rotational bending fatigue strength. It becomes a problem.
  • Patent Document 4 an excellent low cycle fatigue characteristic can be obtained by setting the projection core hardness to a predetermined value or more. However, there are cases where sufficient tempering softening resistance may not be obtained depending on the balance of the amounts of Si, Mn, Cr and Mo added, resulting in a problem that the surface pressure fatigue strength decreases.
  • Patent Document 5 expensive V is an essential element contained, and expensive Mo is allowed to be added in a large amount, resulting in a significant increase in manufacturing cost. Furthermore, these elements increase the precipitation of carbonitrides, and there are concerns about the occurrence of cracks during continuous casting.
  • the present invention provides a case-hardened steel suitable as a material for producing a mechanical structural component having high rotational bending fatigue strength and surface pressure fatigue strength at a relatively low cost, and a method for producing the same.
  • the purpose is to provide.
  • the gist configuration of the present invention is as follows. [1] By mass%, C: 0.15% to 0.30%, Si: 0.80% to 2.00%, Mn: 0.20% to 0.80%, P: 0.003% to 0.030%, S: 0.005% to 0.050% Below, Cr: 1.00% to less than 1.80%, Mo: 0.03% to 0.30%, Al: 0.020% to 0.060%, N: 0.0060% to 0.0300% and O: 0.0003% to 0.0025%
  • a case-hardened steel comprising: 1) the formula and (2) under the range satisfying the formula, the remainder having a component composition composed of Fe and inevitable impurities, and further satisfying the following formula (3).
  • [% M] indicates the content (mass%) of the M element
  • I indicates the fish eye on the fractured surface after carburizing and tempering the case-hardened steel and then performing a rotating bending fatigue test. The area ( ⁇ m 2 ) of oxide inclusions located in the center is shown.
  • a steel slab having a component composition consisting of Fe and inevitable impurities is included under the range that satisfies the formulas (1) and (2).
  • a method for producing a case-hardened steel characterized by obtaining a case-hardened steel which is a steel bar or wire by performing hot working by forging and / or hot rolling.
  • S1 is a cross-sectional area (mm 2 ) of the slab in a cross section orthogonal to the extending direction during hot working
  • S2 is a cross-sectional area of the bar or wire in a cross section orthogonal to the extending direction during hot working. (Mm 2 ) is shown.
  • the case-hardened steel according to any one of [1] to [4] is subjected to machining or forging and subsequent machining to form a gear shape, and then carburizing the case-hardened steel.
  • a method for manufacturing a gear part comprising: quenching and tempering to obtain a gear part.
  • a gear part manufacturing method comprising: carburizing and tempering the case-hardened steel to obtain a gear part.
  • a case hardening steel suitable as a material for producing a mechanical structural component having high rotational bending fatigue strength and surface pressure fatigue strength at a relatively low cost and a method for producing the same. it can. That is, for example, when a gear is manufactured as a machine structural component using the steel of the present invention, not only the rotational bending fatigue characteristics of the tooth root but also the gears excellent in the tooth surface fatigue characteristics are mass-produced. Is possible.
  • C 0.15% or more and 0.30% or less
  • 0.15% or more of C is required.
  • the C content is limited to a range of 0.15% or more and 0.30% or less.
  • it is 0.15% or more and 0.25% or less of range.
  • Si 0.80% or more and 2.00% or less Si increases the resistance to temper softening in the temperature range of 200 to 300 ° C, which is expected to reach during rolling of gears, etc. It is an element that improves hardenability while suppressing formation. Si also has the effect of suppressing the reduction in dislocation density that contributes to the suppression of fatigue crack growth by suppressing the growth of carbides in the same temperature region. In order to obtain a steel having such an effect, the addition of at least 0.80% is indispensable. However, on the other hand, Si is a ferrite stabilizing element, and excessive addition raises the Ac 3 transformation point, and ferrite tends to appear in the core portion having a low carbon content in the normal quenching temperature range, resulting in a decrease in strength. Invite.
  • the Si amount is 2.00% or less, the above-described adverse effects do not occur.
  • the Si content was limited to the range of 0.80% to 2.00%. Preferably it is 0.90% or more and 1.60% or less of range.
  • Mn 0.20% or more and 0.80% or less
  • Mn is an element effective for improving the hardenability, and requires addition of at least 0.20% or more.
  • Mn tends to form an abnormal carburization layer, and excessive addition leads to a decrease in hardness due to an excessive amount of retained austenite, so the upper limit was made 0.80%.
  • it is 0.40% or more and 0.60% or less of range.
  • P 0.003% or more and 0.030% or less P is segregated at the grain boundary and causes the carburized layer and the internal toughness to be lowered. Therefore, the lower the amount of P, the better. Specifically, if it exceeds 0.030%, the above-described adverse effects appear, so the P content is set to 0.030% or less. On the other hand, from the viewpoint of manufacturing cost, 0.003% was made the lower limit.
  • S 0.005% or more and 0.050% or less S forms a sulfide with Mn and has an effect of improving machinability, so is contained at least 0.005% or more.
  • the upper limit was made 0.050%.
  • it is 0.010% or more and 0.030% or less of range.
  • Cr 1.00% or more and less than 1.80% Cr is an element effective not only for hardenability but also for improving the temper softening resistance. However, if the content is less than 1.00%, its addition effect is poor, while 1.80% If it becomes above, the effect which raises temper softening resistance will be saturated, and it will become easy to form a carburizing abnormal layer rather, and will cause the fall of rotation bending fatigue strength. Therefore, the Cr content is limited to a range of 1.00% to less than 1.80%. Preferably it is 1.20% or more and 1.60% or less of range.
  • Mo 0.03% or more and 0.30% or less Mo is an element that has the effect of improving the hardenability, temper softening resistance and toughness, and refining the crystal grain size after carburizing treatment. Since the effect is poor, 0.03% was made the lower limit. On the other hand, if added in a large amount, the amount of retained austenite becomes excessive, which not only causes a decrease in hardness, but also increases the manufacturing cost, so 0.30% was made the upper limit. From the viewpoint of lowering the amount of retained austenite and production cost, the upper limit value is preferably 0.20%.
  • Al 0.020% or more and 0.060% or less
  • Al is an element that forms AlN by combining with N and contributes to the refinement of austenite crystal grains. To obtain this effect, addition of 0.020% or more is required. However, when the content exceeds 0.060%, the formation of Al 2 0 3 inclusions harmful to fatigue strength is promoted, so the Al content is limited to the range of 0.020% to 0.060%. Preferably it is 0.020% or more and 0.040% or less of range.
  • N 0.0060% or more and 0.0300% or less N is an element that combines with Al to form AlN and contributes to refinement of austenite crystal grains. Accordingly, the appropriate addition amount is determined by a quantitative balance with Al, but 0.0060% or more of addition is necessary to exert the effect. However, if added in excess, bubbles are generated in the steel ingot during solidification and deterioration of forgeability is caused, so the upper limit is made 0.0300%. Preferably it is 0.0090% or more and 0.0150% or less of range.
  • O 0.0003% or more and 0.0025% or less
  • O is an element that exists as an oxide inclusion in steel and impairs fatigue strength. Accordingly, the lower the amount of O, the better, but 0.0025% is acceptable. Preferably it is 0.0015% or less. On the other hand, from the viewpoint of manufacturing cost, 0.0003% was made the lower limit.
  • the components in steel in the present invention include the above components, and the balance is Fe and inevitable impurities, but the following selected components are added for the purpose of imparting other characteristics and the like within a range not impairing the working range of the present invention. I can do it.
  • Nb 0.050% or less
  • Nb is a carbonitride-forming element and contributes to improvement of surface fatigue strength and rotational bending fatigue strength by refining the austenite grain size during carburizing.
  • the content is preferably 0.010% or more.
  • the effect is saturated when it exceeds 0.050%, and when it is added in a large amount, the cost increases. Therefore, the upper limit is preferably made 0.050%. More preferably, it is 0.010% or more and less than 0.025%.
  • Ti is a carbonitride-forming element and contributes to the improvement of surface fatigue strength and rotational bending fatigue strength by refining the austenite grain size during carburizing.
  • the content is preferably 0.005% or more.
  • the effect is saturated at 0.025% or more, and if added excessively, coarse carbonitrides are formed, and conversely, the above fatigue strength is lowered, so the upper limit is preferably made 0.025%.
  • Sb 0.035% or less
  • Sb has a strong tendency to segregate at grain boundaries, and suppresses grain boundary oxidation of Si, Mn, Cr, etc., which contributes to improving hardenability during carburizing treatment, thereby preventing abnormal carburization in the extreme surface layer of steel. This has the effect of reducing generation and, as a result, improving rotational bending fatigue strength.
  • the content is preferably 0.003% or more.
  • adding excessively not only leads to an increase in cost, but also reduces toughness, so 0.035% or less is preferable. More preferably, it is 0.005% or more and 0.020% or less of range.
  • Cu 1.0% or less
  • Cu is an element that contributes to the improvement of hardenability.
  • the Cu content is preferably 0.01% or more.
  • the upper limit is preferably 1.0%. More preferably, it is 0.10% or more and 0.50% or less of range.
  • Ni 1.0% or less Ni contributes to improving hardenability and is an element useful for improving toughness.
  • the Ni content is preferably 0.01% or more.
  • the upper limit is preferably 1.0%. More preferably, it is 0.10% or more and 0.50% or less of range.
  • V 0.050% or less
  • V is a carbonitride-forming element like Nb, and contributes to improving fatigue strength by refining the austenite grain size during carburizing. It also has the effect of reducing the grain boundary oxide layer depth. In order to effectively exhibit such an action, when added, the content is preferably 0.005% or more. On the other hand, the effect is saturated when it exceeds 0.050%, and if added excessively, coarse carbonitrides are formed, and conversely, the fatigue strength is lowered, so the upper limit is preferably made 0.050%. More preferably, it is 0.005% or more and 0.030% or less of range.
  • Ca 0.0050% or less Ca is a useful element for controlling the form of sulfide and improving machinability.
  • the Ca content is preferably 0.0005% or more.
  • the upper limit may be made 0.0050%. preferable. More preferably, it is 0.0005% or more and 0.0020% or less of range.
  • Sn 0.50% or less
  • Sn is an effective element for improving the corrosion resistance of the steel surface.
  • the Sn content is preferably 0.003% or more.
  • the upper limit is preferably 0.50%. More preferably, it is 0.010% or more and 0.050% or less of range.
  • Se 0.30% or less Se combines with Mn and Cu and is dispersed as precipitates in the steel. Se precipitates exist stably in the carburizing heat treatment temperature range with little precipitate growth, and have a high pinning effect on the austenite grain size. For this reason, the addition of Se is effective in preventing coarsening of crystal grains. In order to obtain this effect, it is preferable to add at least 0.001% of Se. On the other hand, even if added over 0.30%, the effect of preventing coarsening of crystal grains is saturated. For this reason, the upper limit is preferably set to 0.30%. More preferably, it is 0.005% or more and 0.100% or less.
  • Ta 0.10% or less Ta forms carbides in the steel and suppresses the coarsening of the austenite grain size during the carburizing heat treatment by the pinning effect. In order to obtain this effect, it is preferable to add at least 0.003% Ta. On the other hand, if added over 0.10%, cracking is likely to occur during casting solidification, and there is a concern that wrinkles may remain after rolling and forging, so the upper limit is preferably made 0.10%. More preferably, it is 0.005% or more and 0.050% or less of range.
  • Hf 0.10% or less Hf forms carbides in the steel and suppresses the coarsening of the austenite grain size during the carburizing heat treatment by the pinning effect. In order to obtain this effect, it is preferable to add at least 0.003% of Hf. On the other hand, if added over 0.10%, coarse precipitates are produced during casting solidification, which may lead to a decrease in coarsening suppression ability and fatigue strength, so the upper limit is preferably made 0.10%. More preferably, it is 0.005% or more and 0.050% or less of range.
  • the component composition of steel should just have an above-mentioned element, the remainder Fe, and an unavoidable impurity, However, It is preferable to consist of an above-described element, the remainder Fe, and an unavoidable impurity.
  • the inventors of the present invention have a mechanical structure manufactured by carburizing and tempering the case-hardened steel when the following formulas (1) and (2) are satisfied. It has been found that the parts exhibit excellent bending fatigue strength and surface pressure fatigue strength that are not present in the past. [% Si] + ([% Mn] + [% Cr] + [% Mo]) / 3 ⁇ 1.5 (1) 180-45 [% Mn] -14 [% Cr] -51 [% Mo] +5 [% Si] ⁇ 125 (2) However, [% M] indicates the content (mass%) of the M element.
  • the above formula (1) indicates a factor that affects the temper softening resistance. If the value on the left side is less than 1.5, the effect of improving the temper softening resistance is poor. Also, the above equation (2) shows a factor that affects the amount of retained austenite. If the value on the left side is less than 125, the hardness of the carburized surface layer will decrease, so the reduction in surface fatigue strength and rotational bending fatigue strength will decrease. Will be invited. In the present invention, by satisfying the above equation (1), the temper softening resistance in the temperature range of 200 ° C. or more and 300 ° C.
  • the case-hardened steel of the present invention satisfies the following formula (3) after carburizing and tempering.
  • the value of the left side ⁇ I of the above formula (3) is more preferably 60 or less, and still more preferably 40 or less. ⁇ I ⁇ 80 (3)
  • I on the left side of the above equation (3) is an index indicating the size of the largest oxide inclusions that are the starting points of fatigue fracture, and is obtained as follows. Seven test pieces are collected from the case-hardened steel (bar or wire). The test piece was taken from a position with a diameter of 1/2 in parallel with the drawing direction by hot working (that is, the rolling direction in the case of hot rolling and the drawing direction in forging in the case of hot forging), and is shown in FIG. The parallel part diameter is 8 mm x the parallel part length is 16 mm.
  • the test piece was carburized and tempered under the conditions shown in Fig. 2 (carburizing temperature of 930 ° C for 180 minutes, quenching temperature of 850 ° C for 40 minutes, tempering temperature of 170 ° C for 60 minutes).
  • Rotating bending fatigue test is performed to cause fish eye fracture.
  • the test conditions are that after carburizing, the surface is polished 0.1 mm, the load stress is 1000 MPa, and the rotational speed is 3500 rpm.
  • the fracture surface was observed with a scanning electron microscope, and the area of the oxide inclusions located at the center of the fish eye, that is, the largest oxide inclusions was determined. Measured by image analysis and designated as I.
  • the conventional method for measuring the size, quantity, or density of oxide inclusions in the test area cannot measure the state of oxide inclusions in a large volume, which affects fatigue life. It is not possible to evaluate inclusions that affect In the above-described inclusion evaluation method in the present invention, the size of oxide inclusions that have actually become the starting point of fatigue fracture of steel in a large volume of 5349 mm 3 can be evaluated. More improved.
  • the left side of the above equation (4) is an index indicating the cross-sectional reduction rate when hot working is performed on the slab.
  • the hot working may be hot forging or hot rolling. Furthermore, both hot forging and hot rolling may be performed. If the index shown on the left side of the above equation (4) is less than 0.960, the surface pressure fatigue strength and the rotational bending fatigue strength are reduced due to the large oxide inclusions, resulting in early fatigue failure. More preferably, the left side of the above formula (4) is 0.970 or more, and more preferably 0.985 or more.
  • the case-hardened steel (steel bar or wire) of the present invention manufactured as described above is subjected to machining such as cutting without being subjected to hot forging or cold forging, and is then subjected to a part shape (for example, To a gear shape). Then, a desired part (for example, a gear) is obtained by subjecting this part shape to carburizing quenching and tempering. Further, this part may be subjected to processing such as shot peening.
  • hot forging or cold forging is performed during processing, the size of oxide inclusions changes, but it does not change in the direction of worsening fatigue life. Even if it is a case where it becomes a component, it is effective to use the case hardening steel of this invention.
  • the carburizing quenching / tempering conditions for case-hardened steel are not particularly limited, and may be known or arbitrary conditions.
  • the carburizing temperature is 900 ° C. or higher and 1050 ° C. or lower
  • the quenching temperature is 800 ° C. or higher.
  • the temperature can be set to 900 ° C. or lower for 10 minutes to 120 minutes, and the tempering temperature 120 ° C. to 250 ° C. for 30 minutes to 180 minutes.

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)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

La présente invention concerne un acier cémenté pouvant servir de matière première pour fabriquer, à un coût relativement faible, des composants de structure mécanique qui présentent une résistance élevée à la fatigue en flexion rotative et une résistance élevée à la fatigue par contact ; l'invention concerne également un procédé de fabrication associé. L'acier cémenté de la présente invention est caractérisé en ce qu'il présente une composition contenant, en termes de composants et de pourcentage en masse, C, Si, Mn, P, S, Cr, Mo, Al, N et O dans des relations spécifiées, le reste étant constitué de Fe et d'impuretés inévitables ; et en ce qu'il satisfait à √I ≤ 80 (où I représente la surface, en µm2, d'inclusions d'oxyde situées au centre d'yeux de poisson dans la surface de la fracture après la réalisation d'une carburation, d'une trempe et d'un revenu sur l'acier cémenté, suivis de la réalisation d'essais de fatigue en flexion rotative).
PCT/JP2017/020258 2016-05-31 2017-05-31 Acier cémenté et son procédé de fabrication et procédé de fabrication de composant d'engrenage WO2017209180A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
KR1020187036498A KR102165228B1 (ko) 2016-05-31 2017-05-31 기소강 및 그 제조 방법과 기어 부품의 제조 방법
US16/305,519 US11174543B2 (en) 2016-05-31 2017-05-31 Case hardening steel, method of producing case hardening steel, and method of producing gear part
CN201780032967.XA CN109196134A (zh) 2016-05-31 2017-05-31 表面硬化钢及其制造方法以及齿轮部件的制造方法
CN202410111883.7A CN117888030A (zh) 2016-05-31 2017-05-31 表面硬化钢及其制造方法以及齿轮部件的制造方法
EP17806731.0A EP3467133B1 (fr) 2016-05-31 2017-05-31 Acier cémenté et son procédé de fabrication et procédé de fabrication de composant d'engrenage
MX2018014641A MX2018014641A (es) 2016-05-31 2017-05-31 Acero de cimentación, método para producir acero de cimentación, y método para producir partes de engranaje.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2016-109532 2016-05-31
JP2016109532 2016-05-31
JP2016176921A JP6460069B2 (ja) 2016-05-31 2016-09-09 肌焼鋼およびその製造方法ならびに歯車部品の製造方法
JP2016-176921 2016-09-09

Publications (1)

Publication Number Publication Date
WO2017209180A1 true WO2017209180A1 (fr) 2017-12-07

Family

ID=60478669

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/020258 WO2017209180A1 (fr) 2016-05-31 2017-05-31 Acier cémenté et son procédé de fabrication et procédé de fabrication de composant d'engrenage

Country Status (2)

Country Link
CN (1) CN117888030A (fr)
WO (1) WO2017209180A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021028415A (ja) * 2019-08-09 2021-02-25 日本製鉄株式会社 浸炭歯車用鋼、浸炭歯車及び浸炭歯車の製造方法
CN115074631A (zh) * 2022-06-30 2022-09-20 马鞍山钢铁股份有限公司 Nb-B微合金化高表面硬度高扭矩输出齿轮钢及其制造方法、生产齿轮的渗碳方法和应用
JP7479566B2 (ja) 2020-10-19 2024-05-08 中天鋼鉄集団有限公司 建設機械歯車用鋼の製造方法及びその鍛造品の製造方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014171472A1 (fr) * 2013-04-18 2014-10-23 新日鐵住金株式会社 Matière d'acier de cémentation et élément d'acier de cémentation
JP2015134949A (ja) * 2014-01-17 2015-07-27 Ｊｆｅ条鋼株式会社 肌焼鋼および機械構造用部品

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014171472A1 (fr) * 2013-04-18 2014-10-23 新日鐵住金株式会社 Matière d'acier de cémentation et élément d'acier de cémentation
JP2015134949A (ja) * 2014-01-17 2015-07-27 Ｊｆｅ条鋼株式会社 肌焼鋼および機械構造用部品

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021028415A (ja) * 2019-08-09 2021-02-25 日本製鉄株式会社 浸炭歯車用鋼、浸炭歯車及び浸炭歯車の製造方法
JP7368697B2 (ja) 2019-08-09 2023-10-25 日本製鉄株式会社 浸炭歯車用鋼、浸炭歯車及び浸炭歯車の製造方法
JP7479566B2 (ja) 2020-10-19 2024-05-08 中天鋼鉄集団有限公司 建設機械歯車用鋼の製造方法及びその鍛造品の製造方法
CN115074631A (zh) * 2022-06-30 2022-09-20 马鞍山钢铁股份有限公司 Nb-B微合金化高表面硬度高扭矩输出齿轮钢及其制造方法、生产齿轮的渗碳方法和应用
CN115074631B (zh) * 2022-06-30 2023-07-25 马鞍山钢铁股份有限公司 Nb-B微合金化高表面硬度高扭矩输出齿轮钢及其制造方法、生产齿轮的渗碳方法和应用

Also Published As

Publication number Publication date
CN117888030A (zh) 2024-04-16

Similar Documents

Publication Publication Date Title
JP6098732B2 (ja) 浸炭鋼部品の製造方法及び浸炭鋼部品
JP6468402B2 (ja) 肌焼鋼およびその製造方法ならびに歯車部品の製造方法
JP5333682B2 (ja) 熱間鍛造用圧延棒鋼または線材
JP3562192B2 (ja) 高周波焼入用部品およびその製造方法
WO2017209180A1 (fr) Acier cémenté et son procédé de fabrication et procédé de fabrication de composant d'engrenage
JP6460069B2 (ja) 肌焼鋼およびその製造方法ならびに歯車部品の製造方法
JP2016204752A (ja) 肌焼鋼および肌焼鋼の製造方法
JP6078008B2 (ja) 肌焼鋼および機械構造用部品の製造方法
JP5381171B2 (ja) 高強度肌焼鋼部品の製造方法
JP5332410B2 (ja) 浸炭用鋼材の製造方法
JP6078007B2 (ja) 肌焼鋼および機械構造用部品の製造方法
JP6390685B2 (ja) 非調質鋼およびその製造方法
JP6263390B2 (ja) 耐疲労性に優れた歯車用鋼および歯車
WO2011155605A1 (fr) Acier à haute résistance qui se prête bien à l'usinage et procédé de fabrication de celui-ci
JP2021028414A (ja) 浸炭歯車用鋼、浸炭歯車及び浸炭歯車の製造方法
JP3996386B2 (ja) ねじり疲労特性に優れた浸炭用鋼
CN107532252B (zh) 表面硬化钢
JP7408331B2 (ja) 浸炭肌での歯面疲労強度に優れる機械構造用の肌焼鋼及び該肌焼鋼を用いた機械構造用部品
JP6569650B2 (ja) 肌焼鋼
JP4515329B2 (ja) 耐ケースクラッシング性に優れた熱処理歪の少ない鋼製歯車とその製法
JP5310095B2 (ja) 黒皮外周旋削性とねじり疲労強度に優れた鋼材の製造方法
JP2021161462A (ja) 鋼材

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: 17806731

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 20187036498

Country of ref document: KR

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 2017806731

Country of ref document: EP

Effective date: 20190102