WO2002044435A1 - Acier destiné à une carburation et appareillage carburé - Google Patents

Acier destiné à une carburation et appareillage carburé Download PDF

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Publication number
WO2002044435A1
WO2002044435A1 PCT/JP2001/010523 JP0110523W WO0244435A1 WO 2002044435 A1 WO2002044435 A1 WO 2002044435A1 JP 0110523 W JP0110523 W JP 0110523W WO 0244435 A1 WO0244435 A1 WO 0244435A1
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Prior art keywords
weight
steel
hardness
carburizing
content
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PCT/JP2001/010523
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English (en)
Japanese (ja)
Inventor
Ichie Nomura
Tomoya Kato
Makoto Sumida
Yukio Ito
Masazumi Oonishi
Hideo Aihara
Masahiko Mitsubayashi
Tadashi Eriguchi
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Aichi Steel Corporation
Toyota Motor Corporation
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Priority to JP2002546781A priority Critical patent/JP4136656B2/ja
Publication of WO2002044435A1 publication Critical patent/WO2002044435A1/fr

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    • 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
    • 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
    • C22C38/06—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
    • C22C38/22—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
    • C22C38/26—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
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron

Definitions

  • the present invention relates to a carburized steel and a carburized gear using the same, and more particularly, to a carburized steel excellent in cold forging formability and a carburized gear excellent in low cycle fatigue strength.
  • gears used for automobiles, industrial machines, etc. are made of alloy steels for machine structures such as JIS SMnC, SCr, SCM, SNCM, etc., which are subjected to hot forging, warm forging, or cold forging. After being machined and formed, it is provided with a surface hardening treatment (carburized quenching, induction hardening, soft nitriding, etc.) to improve wear resistance and fatigue strength.
  • a surface hardening treatment carburized quenching, induction hardening, soft nitriding, etc.
  • Japanese Patent Publication No. 7-100840 discloses a gear made of steel to which a large amount of alloying elements such as Mo is added, which provides low cycle fatigue strength (tooth surface fatigue strength such as spalling fracture and impact tooth root). Is known to be improved.
  • alloying elements such as Mo
  • TSC-A-10-152746 and JP-A-11-71654 a small amount of B is added to reduce the alloying component added to the material and compensate for the decrease in hardenability due to this.
  • Carburizing steel has been proposed to be added to achieve both workability and strength.
  • the term “truth” refers to an imperfect quenching layer observed on the gear surface when gas carburizing is usually performed (oxygen in the carburizing gas atmosphere diffuses from the gear surface and is contained in the material).
  • the present invention has been made in view of the above circumstances, and has as its object to provide a carburizing steel excellent in cold forging formability and a carburized gear excellent in low cycle fatigue strength. Disclosure of the invention
  • the present inventors have studied carburizing steel having excellent cold forgeability and carburized gear having excellent low cycle fatigue strength, and as a result, have completed the present invention.
  • the carburizing steel of the present invention contains: C: 0.10 to 0.30% by weight, Si: 0.50% by weight or less, Mn: 0.50 to: I. 50% by weight, P: 0.30% % By weight, S: 0.003% by weight or less, Cr: 0.85 to 2.00% by weight, Mo: 0.35% by weight or less, B: 0.0010 to 0.0050% by weight, A1 : 0.11 to 0.30% by weight, N: 0.0080 to 0.0250% by weight, Nb: 0.01 to 0.10% by weight, Ti: 0.01 to 0.10% by weight The remainder consists of Fe and unavoidable impurities,
  • Hd 83C wt% + 5.5Mn wt% + 4. OCr wt% + 10.5Mo wt% + 12
  • Hd ⁇ 6 O ⁇ TC wt% + 12.5 and is effective
  • a 1% by weight A 1% by weight_2 (N% by weight-0.30Ti% by weight) ⁇ 0.1.
  • C improves the case hardening depth and internal hardness after carburizing and quenching, and greatly affects the improvement of low cycle fatigue strength.
  • the content of C is less than 0.1% by weight, it takes a long time to carburize to obtain the case-hardening depth, so that the cost is high, and the internal strength is also reduced, and the low cycle fatigue strength of the gear is greatly reduced. I do.
  • it exceeds 0.30% by weight the internal hardness after carburizing and quenching increases, and the toughness of the gear teeth decreases significantly, resulting in a decrease in low cycle fatigue strength.
  • the lower limit of the C content is preferably 0.13% by weight, more preferably 0.19% by weight, and the upper limit of the C content is preferably 0.27% by weight. It is more preferably 0.24% by weight.
  • Si is an element added as a deoxidizing agent, it is an element that forms a solid solution in ferrite and strengthens it, and particularly affects cold workability. If the content of Si exceeds 0.50% by weight, carburization may be impaired.
  • the content of Si is preferably 0.35% by weight or less, more preferably 0.15% by weight or less. The lower limit is usually 0.03% by weight.
  • the above Mn is an element added as a deoxidizer, but in order to improve the hardenability of the material, it improves the case hardening depth and internal hardness after carburizing and quenching, and greatly improves low cycle fatigue strength. Affect. However, if the Mn content is less than 0.50% by weight, the formation of trussite in the carburized diffusion layer becomes remarkable, the internal hardness is also reduced, and the low cycle fatigue strength of the gear is greatly reduced. On the other hand, if the content exceeds 1.50% by weight, the transformation temperature of the pearlite during soft annealing decreases, and the hardness of the pearlite portion exceeds Hv 300, thereby deteriorating the cold workability and machinability of the gear.
  • the lower limit of the Mn content is preferably 0.8% by weight, more preferably 1.0% by weight, and the upper limit of the Mn content is preferably 1.5% by weight, more preferably 1. 4% by weight.
  • P is an element that forms a solid solution in ferrite and strengthens it, and in particular, is an element that deteriorates cold workability. If the P content exceeds 0.5% by weight, the austenite grain boundaries during carburization are biased, and the grain boundary strength of the carburized layer decreases.
  • the content of P is preferably 0.015% by weight or less, more preferably 0.012% by weight or less. The lower limit is usually 0.002% by weight.
  • the lower limit of the S content is preferably 0.005% by weight, more preferably 0.008% by weight, and the upper limit of the S content is preferably 0.002% by weight, more preferably It is 0.015% by weight.
  • the above Cr improves the hardenability of the material, thereby improving the case hardening depth and internal hardness after carburizing and quenching, and greatly affecting the improvement in low cycle fatigue strength.
  • B is added
  • the Cr content is less than 0.85% by weight, the formation of troostite in the carburized layer becomes remarkable, while if it exceeds 2.00% by weight, Cr carbides precipitate at the austenite grain boundaries during carburizing, and the carburized layer is formed. The grain boundary strength is lowered, which is not preferable.
  • the lower limit of the Cr content is preferably 0.9% by weight, more preferably 1.0% by weight, and the upper limit of the Cr content is preferably 1.5% by weight, more preferably 1.
  • the Mo content of 3% by weight improves the hardenability of the material, improves the case hardening depth and internal hardness after carburizing and quenching, and is also effective in improving low cycle fatigue strength. However, if the Mo content exceeds 0.35% by weight, the hardness increases remarkably during the production of the gear, the cold workability and machinability deteriorate, and the life of dies and tools is shortened. The cost will be high. In addition, in steels to which B is added, the presence of a large amount of Mo tends to generate troostite in the carburized layer.
  • the content of Mo is preferably 0.25% by weight or less, more preferably 0.20% by weight or less.
  • the lower limit is usually 0.005% by weight.
  • the above B precipitates at the austenite grain boundaries of the carburized layer to improve the grain boundary strength of the carburized layer and to improve the internal hardenability after carburizing and quenching without increasing the material hardness during cold forging. Is an important element. However, if the content exceeds 0.0050% by weight because the effect of improving the hardenability of the carburized layer is small, it becomes easy to form troostite in the carburized layer, and the effect of improving the hardenability is only saturated.
  • the hot forgeability or cold forgeability deteriorates, and if it is less than 0.0010% by weight, the internal hardenability during carburizing and quenching decreases, which is not preferable.
  • the content of B is preferably 0.0010 to 0.0035% by weight, more preferably 0.0015 to 0.0030% by weight.
  • A1 is an element added as a deoxidizing agent, it reacts with N in steel to form A1N, and has an action of preventing austenite crystal grains from being coarsened during carburizing heating.
  • Effective A 1% by weight A 1% by weight_2 (N% by weight-0.30Ti% by weight) ⁇ 0.1 and if the content of A1 is less than 0.11% by weight, In the case of a gear having a high cold working rate, abnormal growth of austenite crystal grains during carburization is observed, and the content of A1 exceeds 0.3% by weight. If this is the case, the incompletely quenched layer on the surface of the gear during carburization becomes deep, which is not preferable.
  • the content of A1 is preferably from 0.11 to 0.20% by weight, and more preferably from 0.11 to 0.15% by weight.
  • the content of A 1 N formed is preferably 200 to 600 ppm, more preferably 250 to 550 ppm, and still more preferably 300 to 500 ppm.
  • 1N precipitates, if the N content is less than 0.0080% by weight, in a cold-worked gear, the amount of precipitated A1N decreases and the austenite crystal grains during carburization become coarse. On the other hand, if it exceeds 0.0250% by weight, the amount of dissolved B decreases, and the hardenability decreases.
  • the lower limit of the N content is preferably 0.008% by weight, more preferably 0.012% by weight, and the upper limit of the N content is preferably 0.025% by weight, more preferably 0.002% by weight.
  • Nb reacts with N or C to generate Nb (C, N), which has an effect of preventing austenite crystal grains from being coarsened during carburizing heating. If the Nb content is less than 0.01% by weight, the above effects are not exhibited. If it exceeds 0.10% by weight, the effect of preventing austenite crystal grains from being coarsened during carburizing heating is saturated, resulting in high cost. I don't like it.
  • the Nb content is preferably 0.01 to 0.07% by weight, more preferably 0.01 to 0.05% by weight.
  • the Ti reacts with N to form TiN, which has the effect of preventing austenite crystal grains from becoming coarse during carburizing heating. If the Ti content is less than 0.01% by weight, the above effects are not exhibited, and if it exceeds 0.10% by weight, the effect of preventing the austenite crystal grains from becoming coarse during carburizing heating is saturated, and the cost is reduced. It is undesirably high.
  • the content of Ti is preferably 0.01 to 0.07% by weight, more preferably 0.01 to 0.055% by weight.
  • Hd 83 C wt% + 5.5 Mn wt% + 4.
  • OC r wt% + 10.5 Mo wt% + 12 is the magnitude of the internal hardness after carburizing and quenching of the carburizing steel having the above composition. The greater the value, the higher the internal hardness after carburizing and quenching.
  • Hd thus obtained satisfies the above formula, Hd ⁇ 60 "wt% + 12.5, it is possible to increase the martensite ratio to 90% or more after carburizing, quenching and tempering.
  • the material is appropriately soft-annealed and has a hardness of Hv 170 or less (preferably ⁇ V 165 or less, (Preferably Hv 160 or less) ferrite + pearlite structure, and the hardness of the pearlite structure is Hv 300 or less (preferably Hv 295 or less, Hv 290 or less is more preferable. This improves the cold forgeability of the carburizing steel.
  • the carburized gear of the present invention is manufactured by using the steel for carburization described above, has a case hardening depth of 0.5 mm or more from the surface and has a hardness of Hv 513, and has a hardening depth within the case hardening depth.
  • the characteristic is that the area ratio is 5% or less.
  • the method of working the carburized gear is not particularly limited. Usually, any one of hot forging, warm forging, and cold forging is performed, followed by machining and carburizing and quenching.
  • the hardness of the surface layer is usually represented by Vickers hardness, and the case depth of hardness Hv 513 is preferably 0.6 mm or more from the surface, more preferably 0.65 mm or more. More preferably, it is 0.7 mm or more. However, the upper limit is usually 1.5 mm, more preferably 1.2 mm. If the case hardening depth is less than 0.5 mm, the fracture starts from the inside of the gear, which is not preferable. On the other hand, if the case hardening depth is 0.5 mm or more, the fatigue strength is remarkably excellent.
  • the method for measuring the hardness of the gear will be described in Examples.
  • Fracture of the above gears due to low cycle fatigue can be caused by tooth surface fatigue delamination caused by plastic deformation inside the tooth surface due to high contact stress on the tooth surface, and high bending stress on the tooth root due to high bending stress on the tooth root. Root impact fatigue fracture and force occur due to plasticity and increased root surface stress (see Fig. 1).
  • carburized and quenched gears have a moderate C concentration distribution from 0.8% of the surface C concentration to the inside of the tooth (uncarburized portion).
  • the strength and toughness of the (uncarburized part) are important, the suppression of troostite formation in the carburized layer and the austenitic crystal grains caused by the toughness In addition to stability, the quenched structure (martensite ratio) inside the tooth due to internal strength is important.
  • the “area fraction of truss evening light” is the depth from the surface after carburizing and quenching.
  • the internal hardness of the pitch portion of the carburized gear may be Hv 350 or more, preferably ⁇ 370 or more, and more preferably Hv 390 or more. If it is less than 350, tooth surface fatigue strength is undesirably reduced.
  • the internal hardness of the root portion of the carburized gear may be Hv 300 or more, preferably Hv 330 or more, more preferably Hv 360 or more. If Hv is less than 300, the root impact fatigue strength is undesirably reduced.
  • the above-mentioned "tooth root part” means an R part which goes from the pitch circle part of the tooth toward the root of the tooth.
  • the pitch portion is Hv 350 or more, and the root portion is Hv 300 or more, more preferably, the pitch portion is Hv 370 or more, and the root portion is Hv. 330 or more, more preferably the pitch part is HV 390 or more, and the tooth root part is Hv 360 or more.
  • the hardness of the pitch portion is Hv 350 or more, and the hardness of the root portion is Hv 300 or more, and the area ratio of the trousers is 5% or less.
  • the hardness of the pitch portion is 370 or more, and the hardness of the root portion is 30 or more, and the area ratio of the trousers.
  • the hardness of the pitch portion is Hv 390 or more, and the hardness of the root portion is Hv 360 or more, and the troostite area ratio is 4.7% or less, ( 4) Particularly preferably, the hardness of the pitch portion is Hv400 or more, the hardness of the root portion is Hv390 or more, and the area ratio of the trousers is 4.5% or less.
  • a steel having the above structure and properties can be obtained by performing normal carburizing, quenching and tempering.
  • the gear diameter is equivalent to a round bar, and the outer diameter is preferably 40 mm or less, more preferably 30 mm or less, and even more preferably 25 mm or less.
  • the quenching medium is preferably 200 and the following oil quenching is preferred.
  • the carburizing atmosphere may be any one of gas carburizing, carburizing and nitriding, and vacuum carburizing.
  • Hd 83C weight% + 5.5Mn weight% + 4.01 "weight% + 10.5 Mo weight% + 12
  • Hd 83C weight% + 5.5Mn weight% + 4.01 "weight% + 10.5 Mo weight% + 12
  • the stress of the tooth root portion which is an effect of the cold forged gear, is obtained.
  • FIG. 1 is an explanatory view showing the form of low cycle fatigue fracture of a gear.
  • FIG. 2 is an explanatory diagram showing a heat pattern for carburizing, quenching and tempering a bevel gear.
  • FIG. 3 is an explanatory diagram showing a low cycle fatigue test of a bevel gear.
  • Tables 6 and 7 show the calculation results of 1% by weight of effective A. In Tables 4 to 7, those whose constituent element content is out of the range of the present invention are indicated by an asterisk beside the numerical value.
  • the ingots A to P, Ql, R1, and S were heated at 1200 ° C or higher for 0.5 hours, and then hot forged at a temperature of 1000 to 1200 ° C to produce round bars with a diameter of 30 mm. . This was annealed from 900 ° C to 600 ° C at a cooling rate of 75 tZ to obtain carburizing steel.
  • the carburizing round bars of A to H, ⁇ , P and S have the hardness (hardness of the base and pearlite) and the cold workability (70% (Deformation resistance and critical working ratio) were measured by the following methods. Table 8 shows the results.
  • the substrate hardness was measured at a load of 10 kg using a Vickers hardness tester (model: AVK_C2, manufacturer: AKAS HI).
  • the hardness of the pearlite portion was measured by measuring the micro Vickers hardness under a load of 10 g.
  • Deformation resistance was measured by loading a test piece (without notch) with a diameter of 10 mm and a height of 15 mm using a 100 t universal test device (model: RH_100, manufacturer name: manufactured by Shimadzu Corporation) at a load cell moving speed of ImmZ.
  • the compression load at 70% upsetting was measured, and the deformation resistance obtained by using the deformation resistance measurement method by the end face constrained compression proposed by the Japan Society for Technology of Plasticity is shown in Table 8. (1980) pp. 529-532
  • the limit processing rate is determined by performing an end face restraint test on the above test piece using the above equipment, applying a load cell at a moving speed of lmm / min, and limiting the upsetting rate when the end (circumferential portion) cracks.
  • the carburizing round bar was cold forged with a module of 4.8 and a number of teeth of 10
  • a bevel gear with a pitch circle diameter of 48.8 mm was manufactured by carburizing, quenching and tempering with the heat pattern shown in Fig. 2 and further grinding the inner diameter and the like.
  • the bevel gear was set in a hydraulic fatigue tester as shown in Fig. 3, and a bevel gear fatigue test was performed as follows. A jig having a curvature equivalent to that of the actual gear was fabricated on the test gear, and a complete one-sided fatigue test was performed. Using the acoustic emission, the crack generation time was regarded as the life, and the tooth surface or root origin was determined by magnetic particle flaw detection. Table 9 shows the results.
  • the case hardening depth and the internal hardness at the pitch portion and the root portion of the bevel gear were measured, and further, the troostite structure within the case hardening depth was observed and the austenite crystal grains were mixed.
  • Table 9 also shows the results.
  • the case hardening depth was measured with a load of 300 g using a micro Vickers hardness tester (model: MVK-E, manufacturer name: AKASH I).
  • the internal hardness was measured at a load of 10 kg using a Vickers hardness tester (model: AVK-C2, manufacturer: AKASH I).
  • the area ratio of troostite was determined by the following method using an image analyzer (model: LUZEX-IIIU, manufacturer name: manufactured by NI RECO). After the nail corrosion, the area ratio of the black corroded portion of the troostite structure was calculated. Austenitic crystal grains were observed using an optical microscope (model: BX60M, manufacturer name, manufactured by OLYMPUS).
  • the P steel had an Mn content outside the range of the present invention and had a good base hardness of Hv 159, but had a high pearlite hardness and a low deformation resistance in cold workability of less than 100 OMPa.
  • the critical processing rate was also inferior.
  • S steel did not contain B, Nb and Ti, and was inferior in the base material hardness and pearlite hardness, and the cold workability was further inferior to the O and P steels in the critical working ratio.
  • Steel V had a C content outside the range of the present invention and had a good pearlite hardness of Hv 171.However, the base hardness was high at Hv 171 and the deformation resistance in cold workability exceeded 1000 MPa. Was expensive.
  • the W steel had a Mn content outside the range of the present invention and had a good base hardness of Hv 158, but had a high pearlite hardness of Hv 305 and was inferior to the limit workability.
  • the steels A to H of the steels of the present invention were excellent in the base material hardness and the pearlite hardness, had a deformation resistance of 1000 MPa or less even in cold workability, and had a critical work ratio exceeding 70%.
  • steel C has low deformation resistance
  • steel D has a critical working ratio of over 80%, showing excellent cold workability.
  • the steels A to H of the steel of the present invention correspond to Hd in Table 4.
  • the content of C is higher than the range of the present invention, and the effective A 1% by weight is low, so that mixed grains are generated and the toughness is reduced, so that the tooth root strength is reduced and low cycle fatigue is caused.
  • the strength has decreased.
  • the Cr content is lower than the range of the present invention and the H di-Hd 2 value is out of the range of the present invention, a large amount of trussite precipitates, the tooth surface strength is reduced, and the cycle is low. The fatigue strength has been reduced.
  • Hd i-Hd 2 values and effective A 1 wt% is within the scope of the present invention.
  • the J steel had an effective A of 1% by weight within the range of the present invention except that the Mn content and the Hd Hd 2 value were outside the range of the present invention.
  • the K steel had an H di-H d 2 value and an effective A of 1% by weight within the range of the present invention except that the content of Mo was outside the range of the present invention.
  • L steel C r, the content of A 1, Hd - H d 2 values and effective A 1 wt% were outside the scope of the present invention.
  • Hd i-Hd 2 values and effective A 1 wt% were within the limits of the present invention.
  • N steel except the content of A 1 and N are outside the scope of the present invention, Hd ⁇ _ ⁇ Hd 2 values and effective A 1 wt% is within the scope of the present invention.
  • Q 1 steel except the content and HDI-Hd 2 value of C r, N b and T i is outside the range of the present invention, effective A 1 wt% is within the scope of the present invention.
  • the length of steel 1 ", the content of A1, the Hd i -Hd 2 value and the effective A 1% by weight were out of the range of the present invention.
  • the S steel was Cr, A 1, N, B, Nb and Ti content, Hd
  • the values and 1% by weight of effective A were outside the scope of the present invention.
  • the T steel had an effective A content of 1% by weight, and the U steel had an H di-Hd 2 value outside the range of the present invention.
  • Steel V was out of the scope of the present invention in the content of C and A1 and the effective A1% by weight.
  • the W steel had Cr and Mn contents and Hd 1 —Hd 2 values outside the range of the present invention.
  • the area ratio of trussite was small, and the austenite crystal grains were also sized.
  • the 300 times strength also exceeded 80KN, showing excellent low cycle fatigue strength.
  • the Ql-33 steel and the R1-20 steel are those described in JP-A-117-1654 and JP-A-10-15746, respectively.
  • Q2 to 5, 7, 9 to 11, 13 to: 15, 20, 21, 23, 32 steel and R 1 to 11, 13, 14, 14, 16 to 19 steel are shown in Table 4.
  • Hc ⁇ -Hd 2 values in Tables 6 and 7 and Tables 6 and 7 Effective A in 1% by weight is outside the scope of the present invention.
  • Q 6, 8, 12, 16 ⁇ 19 , 25, 28 steel effective A 1 wt% is more than 0.1 but, HDI-Hd 2 value takes a negative value.
  • Q22, 24, 26, 27 steel and R12, 15, 20 steel are Hd However, 1% by weight of effective A is less than 0.1.

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  • Gears, Cams (AREA)

Abstract

L'invention concerne un acier destiné à une carburation, très indiqué pour le forgeage à froid, ainsi qu'un appareillage carburé présentant une excellente résistance à la fatigue oligocyclique. L'acier de carburation est constitué de 0,10 à 0,30 % en pds de carbone, jusqu'à 50 % en pds de silicium, de 0,50 à 1,50 % en pds de manganèse, jusqu'à 0,030 % en pds de phosphore, jusqu'à 0,030 % en pds de soufre, de 0,85 à 2,00 % en pds de chrome, jusqu'à 0,35 % en pds de molybdenum, de 0,0010 à 0,0050 % en pds de bore, de 0,11 à 0,30 % d'aluminium, de 0,0080 à 0,0250 % en pds d'azote, de 0,01 % à 0,10 % en pds de niobium, de 0,01 % à 0,10 % en pds de titane, de fer et le reste étant d'inévitables impuretés, à condition que l'acier obéisse à Hd= % en pds de 83C + % en pds de 5,5Mn + % en pds de 4,0Cr+ % en pds de 10,5Mo+12 et Hd ≥ % en pds de 60∑ C+12,5, et le % en pds effectif d'Al= % en pds d'Al 2( % en pds de N - % en pds de 0,30Ti) ≥ 0,1.
PCT/JP2001/010523 2000-12-01 2001-11-30 Acier destiné à une carburation et appareillage carburé WO2002044435A1 (fr)

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JP2002546781A JP4136656B2 (ja) 2000-12-01 2001-11-30 浸炭用鋼及び浸炭歯車

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JP2000-367204 2000-12-01
JP2000367204 2000-12-01

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WO2002044435A1 true WO2002044435A1 (fr) 2002-06-06

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008179849A (ja) * 2007-01-24 2008-08-07 Jfe Bars & Shapes Corp 耐衝撃疲労特性に優れた歯車用鋼及びそれを用いた歯車
US8801873B2 (en) 2009-03-30 2014-08-12 Nippon Steel & Sumitomo Metal Corporation Carburized steel part
US8980022B2 (en) 2009-01-16 2015-03-17 Nippon Steel & Sumitomo Metal Corporation Case hardening steel, carburized component, and manufacturing method of case hardening steel
JP2015127435A (ja) * 2013-12-27 2015-07-09 株式会社神戸製鋼所 浸炭後の曲げ疲労特性に優れた鋼材およびその製造方法並びに浸炭部品
US9469883B2 (en) 2009-05-13 2016-10-18 Nippon Steel & Sumitomo Metal Corporation Carburized steel part having excellent low cycle bending fatigue strength
EP3124637A4 (fr) * 2014-03-26 2017-08-30 Nippon Steel & Sumitomo Metal Corporation Élément de tôle d'acier formé à chaud à haute résistance

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08260039A (ja) * 1995-03-24 1996-10-08 Sumitomo Metal Ind Ltd 浸炭肌焼鋼の製造方法
JPH0967644A (ja) * 1995-08-28 1997-03-11 Daido Steel Co Ltd 歯切り性に優れた浸炭歯車用鋼
JPH108199A (ja) * 1996-06-14 1998-01-13 Daido Steel Co Ltd 浸炭硬化性に優れた肌焼鋼

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08260039A (ja) * 1995-03-24 1996-10-08 Sumitomo Metal Ind Ltd 浸炭肌焼鋼の製造方法
JPH0967644A (ja) * 1995-08-28 1997-03-11 Daido Steel Co Ltd 歯切り性に優れた浸炭歯車用鋼
JPH108199A (ja) * 1996-06-14 1998-01-13 Daido Steel Co Ltd 浸炭硬化性に優れた肌焼鋼

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008179849A (ja) * 2007-01-24 2008-08-07 Jfe Bars & Shapes Corp 耐衝撃疲労特性に優れた歯車用鋼及びそれを用いた歯車
US8980022B2 (en) 2009-01-16 2015-03-17 Nippon Steel & Sumitomo Metal Corporation Case hardening steel, carburized component, and manufacturing method of case hardening steel
US8801873B2 (en) 2009-03-30 2014-08-12 Nippon Steel & Sumitomo Metal Corporation Carburized steel part
US9469883B2 (en) 2009-05-13 2016-10-18 Nippon Steel & Sumitomo Metal Corporation Carburized steel part having excellent low cycle bending fatigue strength
JP2015127435A (ja) * 2013-12-27 2015-07-09 株式会社神戸製鋼所 浸炭後の曲げ疲労特性に優れた鋼材およびその製造方法並びに浸炭部品
EP3124637A4 (fr) * 2014-03-26 2017-08-30 Nippon Steel & Sumitomo Metal Corporation Élément de tôle d'acier formé à chaud à haute résistance

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JPWO2002044435A1 (ja) 2004-04-02

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