[go: up one dir, main page]

WO2002006546A1 - Segment de piston presentant une resistance elevee a l'erosion, a la fissuration et a la fatigue, procede permettant de produire ce segment et combinaison segment de piston et bloc-cylindres - Google Patents

Segment de piston presentant une resistance elevee a l'erosion, a la fissuration et a la fatigue, procede permettant de produire ce segment et combinaison segment de piston et bloc-cylindres Download PDF

Info

Publication number
WO2002006546A1
WO2002006546A1 PCT/JP2001/006127 JP0106127W WO0206546A1 WO 2002006546 A1 WO2002006546 A1 WO 2002006546A1 JP 0106127 W JP0106127 W JP 0106127W WO 0206546 A1 WO0206546 A1 WO 0206546A1
Authority
WO
WIPO (PCT)
Prior art keywords
ring
less
steel
stainless steel
resistance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2001/006127
Other languages
English (en)
Japanese (ja)
Inventor
Junya Takahashi
Toru Onuki
Shigeo Inoue
Mitsutaka Sasakura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Riken Corp
Tokusen Kogyo Co Ltd
Original Assignee
Riken Corp
Tokusen Kogyo Co Ltd
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 Riken Corp, Tokusen Kogyo Co Ltd filed Critical Riken Corp
Priority to US10/333,326 priority Critical patent/US20040040631A1/en
Priority to EP01949987A priority patent/EP1304393B1/fr
Priority to DE60122164T priority patent/DE60122164T2/de
Priority to KR10-2003-7000751A priority patent/KR100507424B1/ko
Priority to BRPI0112573-7A priority patent/BR0112573B1/pt
Publication of WO2002006546A1 publication Critical patent/WO2002006546A1/fr
Anticipated expiration legal-status Critical
Priority to US11/657,015 priority patent/US20070187002A1/en
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—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
    • 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
    • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
    • 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
    • C21D9/40—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rings; for bearing races
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • 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
    • 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
    • C23C8/24—Nitriding
    • C23C8/26—Nitriding of ferrous surfaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

Definitions

  • the present invention relates to a bis-ring used in an internal combustion engine, and particularly to a scuffing resistance (seizure resistance), a cracking resistance (breakage resistance) and a fatigue resistance.
  • the present invention relates to an excellent high chrome martensitic stainless steel-made bis-nitride ring and a method for producing the same. Background art
  • steel materials for piston rings are broadly classified into carbon steel, silicon chrome steel, and martensitic stainless steel. Chromium is applied to steel and silicon chromium steel, while gas nitriding is applied to martensite stainless steel. In conventional steel piston rings, chrome plating was almost the only force applied.S, problems with scuffing of the plating layer under high load, and wastewater treatment Due to environmental issues, bis-nitride rings have become the mainstream in recent years.
  • JIS SUS440B equivalent material is the main steel type used for bis-nitride ring.
  • nitrogen atoms penetrate into the steel from the surface and diffuse to form a nitrided layer.
  • the nitride in the nitride layer is mainly a compound with Cr, V, and Mo, or a compound thereof with Fe as a solid solution.
  • Cr which is contained abundantly in steel, dissolves in the matrix and exists as Cr carbide.However, it has a greater affinity for nitrogen than carbon, so it can be used for nitriding. Nitrogen diffused from the surface and the Cr carbide react to form Cr nitride. Since SUS440B has a high Cr content of 17.0-18.0%, a relatively hard nitrided layer in which hard Cr nitrides are dispersed at an appropriate area ratio is obtained for the above-mentioned reasons, and excellent wear resistance is obtained. Shows resistance and anti-scratching properties.
  • Japanese Patent Application Laid-Open No. H11-80907 discloses that although Cr is slightly lower than 5.0 and less than 12.0%, Si: 0.25% and Mn: Excellent by containing 0.30% or less, one or more of Mo, W, V, Nb: 0.3-2.5%, or Cu: 4.0% or less, Ni: 2.0% or less, ⁇ : 1.5% or less and this the anti ska Zuph fin grayed resistance is obtained, by the this to the Japanese Patent Laid-Open No. 11-106874, to 4.0% and the content of M 7 C 3 type carbide that exists in the tissue area% It is disclosed that a bistable ring material having excellent workability in addition to squatting resistance can be obtained.
  • This scattering is often caused by the occurrence of a crack perpendicular to the sliding direction of the outer periphery of the piston ring. It is observed along a relatively coarse layered grain boundary compound (also referred to by those skilled in the art as a seagull phase) which is almost parallel to the surface formed at the crystal grain boundary of the nitride layer on the ring sliding surface. .
  • the purpose of the present invention is to use an internal combustion engine with a high rotation speed and a high combustion pressure and a high load, especially a diesel engine employing a lightweight steel monoblock that is expected to increase in the future.
  • Bi-stone ring made of high chrome martensitic stainless steel, which does not cause abrasion, scuffing, cracking, and fatigue breakage, and has excellent cost performance. Its purpose is to provide a manufacturing method thereof. Disclosure of the invention
  • the structure of the nitrided layer in the high chrome martensite stainless steel is generally tempered and has a form in which hard nitrides are mainly dispersed in the matrix of the martensite. Scuffing is based on its mechanical force, microscopic irregularities on the sliding surface, that is, the size of the hard particles dispersed in the relatively soft matrix. Strongly related to dispersion. When observing the cross section of the surface layer having such a structure, the convex hard particles come into contact with the sliding surface of the mating member, and the relatively soft matrix becomes relatively concave. I have.
  • the probability of the nitrided steel coming into direct contact with the counterpart material is reduced, and a lubricating oil film is formed in the recess, and pressure is generated in the oil film during sliding, thereby reducing the contact pressure.
  • the lubrication of the convex contact portion can be prevented to prevent the occurrence of scuffing.
  • a particle size of submicron to several micron size is required, and the dispersion amount is 5% in area ratio. % Is desirable. If the hard particles are extremely small or the amount of dispersion is small, the mechanism due to the effect of the convex hard particles cannot be expected.
  • This anti-scratch mechanism depends on the condition of the sliding surface of the mating material.
  • the surface roughness of the entire surface of the cylinder is likely to be roughened by grinding, and the plastic flow of the ferrite phase Is often blocked by graphite.
  • Such iron is also suitable for sliding It is also “familiar” among traders. )
  • hard particles composed of Cr nitride as the main part of the nitrided layer are dispersed in an appropriate size and uniformity, and a large number of particles are dispersed. This reduces the contact probability between the matrix and the cylinder, and in particular reduces the size of the grain boundary compounds generated by the nitriding treatment to reduce the
  • the present inventors have found that it is indispensable to suppress the generation of cracks and to prevent the spread of cracks even if they occur.
  • eutectic Cr carbide phase: (Cr, Fe) 7 C 3
  • ⁇ phase primary austenite
  • Cr carbides with a maximum diameter exceeding 20 ⁇ are observed.
  • the refinement of this coarse primary eutectic carbide is achieved by adding at least 0.25% of nitrogen (N) to iron and steel, Vol. 82, No. 4, pp. 309-314 (1996).
  • Japanese Patent Application Laid-Open Nos. 9-289053 and 9-287058 disclose rolling bearings utilizing the technique of refining Cr carbide by adding N.
  • the present inventors have considered the mechanism of the above-mentioned scuffing, and found that the crack formed on the surface formed at the crystal grain boundary of the nitrided layer on the piston ring sliding surface is observed.
  • microstructure such that the layered grain boundary compound in the inside becomes fine, high-speed, high-output, high-combustion-pressure internal combustion engines, especially recent lightweight steel monobloc diesel engines Even when used in such applications as high-chromium martensitic stainless steel bis-nitride rings, which are excellent in wear resistance, scuffing resistance, cracking resistance, and fatigue resistance. What you can get And found.
  • the nitrided piston ring made of high chrome martensitic stainless steel according to the present invention has a weight of 0 / chrome martensitic stainless steel.
  • C 0.3-1.0%, Cr: 14.0-21.0%, N: 0.05-0.50%, Mo-, V-, W-, Nb-0.03-3.0%, total of at least one or more types, Si: 0.1-1.0 %, Mn: 0.1-1.0%, P: 0.05% or less, S: 0.05% or less, with the balance Fe and Hard particles of nitrides, carbides, and carbonitrides mainly consisting of nitrides on the surface of the sliding nitride layer consist of unavoidable impurities and have an average diameter of 0.5-2 m and a maximum diameter of 7 mm.
  • the nitrided sliding surface having the above-mentioned structural characteristics is such that the Vickers hardness is in the range of 900-1400, and the depth of the nitrided layer is sufficient from the surface subjected to the nitriding treatment. It is characterized by having a thickness.
  • a steel having a predetermined composition is melted, nitrogen is added, and the ingot is manufactured. Then, hot rolling, annealing, cold drawing, and cold rolling are performed to approximate the predetermined cross section of the steel ring, and quenching and tempering are performed to obtain a wire.
  • the wire is bent into a ring shape and subjected to strain relief heat treatment, side surface rough grinding, nitriding, removal of the surface compound layer, grinding between the abutment, side finish grinding, outer wrapping, etc.
  • C forms a solid solution in Fe to increase the hardness of the matrix, It easily combines with Cr, Mo, V, W, and Nb to form carbides.
  • Carbides by connexion nitride layer during nitriding treatment changes to nitride as a main, improving the wear resistance and ska Tsu off I ring of the sliding surface of the bis tons Li in g c
  • the term “heat loss” refers to a phenomenon in which the sealing property deteriorates due to a decrease in tension due to the cleaving phenomenon during use of the biston ring at a high temperature.
  • it reacts with C in steel to form Cr carbide.
  • This Cr carbide easily reacts with N invading from the surface by nitriding, and becomes CrN in the nitrided layer and is dispersed as hard particles. These hard particles in the nitrided layer significantly improve the wear resistance and scuffing resistance of the piston ring sliding surface.
  • the Cr content is less than 14%, the formation of Oehic compounds is small, and if it exceeds 21%, the toughness is reduced due to the formation of ⁇ ferrite and the Cr concentration in the matrix becomes too high. Since the Ms (martensite transformation start temperature) may be lowered and sufficient quenching hardness may not be obtained, the Cr content should be in the range of 14-21%. Preferably it is in the range of 16-19%.
  • N forms an interstitial solid solution with Fe as does C. Due to the addition of N, for example, the C concentration at the left end of the eutectic line in the 17% Cr isoconcentration cross section of the Fe-Cr-C phase diagram changes the C concentration of the Shifting to a higher concentration side suppresses the eutectic reaction, thereby suppressing the crystallization of the ⁇ phase. C subsequent supersaturated during cooling, New precipitates around as a lame error like M 23 C 6 and Micromax 2 New precipitates primary crystal ⁇ grain boundaries.
  • New is out ⁇ phase crystallizes is less than 0.05%, and if it exceeds 0.50% increases the amount of precipitation of Micromax 2 New rod-shaped, since the toughness is lowered, New is in the range of 0.05-0.50%. It is preferably in the range of 0.10-0.30%. Further, the solid solution of ⁇ to Conclusions click scan during inhibit the diffusion of C in the Conclusions click scan, the grain boundary compounds (eventually changed to Fe 3 N Fe 3 C It also contributes to the miniaturization of). If the addition of N is 0.2% or less, it can be added at normal pressure, and if it exceeds 0.2%, melting in a pressurized] ⁇ 2 atmosphere is required. Yo Therefore, from the viewpoint of the N addition force Q, the range of 0.05 to 0.20% is preferable.
  • Mo, V, W, and Nb are all carbide-forming elements that improve wear resistance and anti-scratching properties.
  • Mo has an effect of preventing softening during tempering and nitriding, and plays an important role in the dimensional stability of the bis-ring.
  • V is an element that promotes nitriding and has the effect of increasing the hardness of the nitrided layer.
  • any of the elements is useful because it improves various performances required for piston ring, but if the total of at least one of Mo, V, W, and Nb is less than 0.03%, The effect is negligible, and if it exceeds 3%, the workability is significantly impaired and the toughness is reduced, so that the total of at least one of Mo, V, W and Nb is 0.03-3.0 % Range.
  • Si is added as a deoxidizing agent, and forms a solid solution in Fe to increase temper softening resistance and improve so-called heat resistance. If it is less than 0.1%, the effect is small. If it exceeds 1.0%, the toughness is reduced. Therefore, the Si content is in the range of 0.1 to 1.0%.
  • Mn is also added as a deoxidizing agent like Si. If the content is less than 0.1%, the effect is small, and if it exceeds 1.0%, the workability is reduced. Therefore, Mn is set in the range of 0.1 to 1.0%.
  • the content is set to 0.05% or less. Preferably, it is 0.03% or less.
  • the content is set to 0.05% or less. Preferably, it is 0.03% or less.
  • the nitride in the nitrided layer is fine and numerous.
  • the main surface of the sliding nitride layer is C r
  • Hard particles of nitrides, carbides and carbonitrides consisting of the following nitrides should be in the range of 0.2-2 // m in average diameter, 7 xm or less in maximum diameter, and 5-30% in area ratio.
  • the average particle size is less than 0.2 m, the effect as a convex hard particle for preventing scuffing cannot be expected, and when it exceeds 2 / _tm, the problem of scuffing when the load is high is high. Remains.
  • the maximum diameter exceeds 7 m, the uniformity of the tissue is poor, and in the case of a high load, the problem of scuffing remains.
  • the area ratio is less than 5%, there remains a problem in anti-scratching resistance, and if it exceeds 30%, it becomes difficult to process the wire after melting or to bend the wire into a ring shape.
  • it is 10-25%.
  • the nitrided layer cross-section in the longitudinal direction of the bis-ring which is substantially composed of matrix and hard particles.
  • the size (length) of the grain boundary compound to be used is 20 / m or less at maximum. Exceeding the maximum length of 20 causes problems with cracking under heavy loads.
  • the nitride layer structure of the present invention as described above is caused by the microstructure of stainless steel.
  • the ⁇ phase ((Cr, Fe) 7 C 3 ) does not exist. This can be achieved by adding nitrogen.
  • the second, secondary carbides (epsilon phase: (Fe, Cr) 23 C e) precipitated when kept at the quenching temperature prior to nitriding treatment there are many fine.
  • the quenching temperature As the temperature is lower, more carbides precipitate in an equilibrium manner, so the ( ⁇ + ⁇ ) region
  • quenching temperature As the temperature is lower, more carbides precipitate in an equilibrium manner, so the ( ⁇ + ⁇ ) region
  • quenching temperature As the temperature is lower, more carbides precipitate in an equilibrium manner, so the ( ⁇ + ⁇ ) region
  • quenching temperature As low as possible, it is possible to precipitate as many f carbides as possible.
  • quenching from a low temperature range makes the crystal grains fine in order to suppress the growth of ⁇ crystal grains, and thus makes it possible to make the grain boundary compound phase formed in the subsequent nitriding treatment also fine.
  • the preferred quenching temperature is in the range of 850-1000 ° C. Below 850 ° C, Prescribed hardness cannot be obtained due to lack of cracking and precipitation of ⁇ phase.At quenching temperatures exceeding 1000 ° C, coagulation of carbides and coarsening of ⁇ grains occur at the stage where quenching temperature is maintained. As a result, nitrides and grain boundary compound phases formed in the subsequent nitriding process are coarsened. The high hardness of 900-1400 can be obtained to a sufficient depth in a relatively short time in the nitrided layer.However, the relatively small quenching temperature allows relatively fine ⁇ grains to be obtained.
  • the reason for performing the nitriding treatment in the range of 450 to 600 ° C has been considered to be that the solubility of N in the -Fe lattice becomes maximum at about 590 ° C, It is not necessary to limit to this temperature if the grain boundary is the main diffusion path of N.
  • arbitrary processing at low as Ru can temperature preferred is 1 in a range of practical point of view from 450- 600 D C - it was 20 hours.
  • FIG. 1 is a backscattered electron image photograph of the sliding nitride layer surface by a scanning electron microscope.
  • FIG. 1 (a) corresponds to Example 1 and
  • FIG. 2 (b) corresponds to Comparative Example 1.
  • FIG. 2 is an optical micrograph of a cross section of the nitride layer.
  • FIG. 2 (a) corresponds to Example 1 and
  • FIG. 2 (b) corresponds to Comparative Example 1.
  • FIG. 3 is a diagram showing a test piece for a scuffing test.
  • FIG. 4 is a view showing an operation mechanism of the friction and wear tester.
  • Fig. 5 is a diagram showing the operation mechanism of the Biston ring fatigue tester.
  • Figure 6 is a graph of the fatigue limit diagram.
  • FIG. 7 is a photograph of a crack formed on the sliding surface of Comparative Example 13. BEST MODE FOR CARRYING OUT THE INVENTION
  • Example 1-11 Jl-Jll
  • Comparative Example 1-8 H1-H8
  • High chrome martensite stainless steel with the chemical composition shown in Table 1 was melted using a 10 kg vacuum induction melting furnace. However, steel with less than 0.2% N was added with nitrogen at normal pressure, and steel with 0.2% or more was melted in a pressure 2 atmosphere. Next, it is made into a linear material with a diameter of 12 mm through hot working, and after pickling, subjected to spheroidizing annealing at 750 ° C for 10 hours.After a predetermined process, a rectangular cross section of 3.5 mm X 5.0 mm is formed. It was processed into a wire rod.
  • quenching and tempering are performed in a quenching furnace (Ar atmosphere) at 930 ° C for about 10 minutes, and after air-cooled quenching, they pass through a tempering furnace (Ar atmosphere) at 620 ° C for about 25 minutes.
  • the test was performed in a continuous manner, and nitriding was performed on a test piece obtained by cutting a wire into a length of 50 mm, and gas nitriding was performed at 570 ° C for 4 hours.
  • the quenching temperature of Comparative Example 1 (HI) was performed at iioo ° c, which was conventionally performed conventionally. Other conditions are the same as those of the other examples and comparative examples.
  • FIG. 1 and Fig. 2 show the backscattered electron images (Figs. 1 (a) and (b)) of the sliding nitride layer surface of Example 1 (J1) and Comparative Example 1 (HI) by a scanning electron microscope.
  • Optical micrographs (FIGS. 2A and 2B) of the cross section of the layer are shown. The hard particles are black in the backscattered electron image and white in the light micrograph.
  • the size of the hard particles is small, and the size of the grain boundary compound in the cross section of the nitride layer is also extremely small.
  • Table 2 shows the results of quantification of the structures of Example 1-11 (J1-J11) and Comparative Example 1-8 (H1-H8). , The area ratio, the maximum length of the grain boundary compound in the cross section of the nitrided layer, and the hardness of the sliding surface of the nitrided layer are shown.
  • the scuffing test is a U-shaped 2-pin integrated test piece with a total length of 45 mm as shown in Fig. 3 made from a wire test piece.
  • the test was performed using a friction and wear tester (manufactured by RIKEN: trade name "Tribolic 1").
  • the sliding surface at the tip of the pin (Fig. 4, reference numeral 1) has a convex shape with a radius of 20mm and grinds a 5-20 ⁇ m thick compound layer (white layer) formed on the surface by gas nitriding. Removed and polished to a mirror finish.
  • the FC250 disk (Fig. 4, reference numeral 2) was prepared by adjusting the surface roughness (Rz) of the sliding surface to 1-2 m.
  • Fig. 4 shows the operating mechanism of the friction and wear tester, and the fuzzing test conditions are shown below.
  • Pressing load Increase from the initial l.OMPa every 0.2MPa, pressure increase until scatting occurs
  • Lubricating oil Motor oil (Product name, Nippon Oil Motor Oil P # 20) Lubricating oil temperature: 80 ° C (near the outlet)
  • the squashing surface pressure was calculated from the load applied when squashing occurred and the wear area of the sliding surface.
  • Table 3 shows the scuffing surface pressure of Example 1-11 (J1-J11) and Comparative Example 1-8 (H1-H8).
  • Example 1-11 J1-J11 according to the present invention was found to have improved anti-scuffing properties as compared with Comparative Examples 1, 3, and 5-7 (HI, H3, H5-H7). I understand.
  • Comparative Example 9 H9
  • the hardness of the nitrided layer was a low value of 860.
  • Example 1 In the material having the chemical composition of Example 1, a nitrided layer structure obtained by air-quenching quenching from the quenching temperature shown in Table 7 in the quenching process after wire rod processing and performing gas nitriding through the same predetermined process as in Example 1 Quantified. Table 5 shows the results.
  • a pressure ring with a rectangular cross section of nominal diameter (95.0 mm), thickness (a,) 3.35 mm, width (h,) 2.3 ram (implemented Example 15 and Comparative Example 12).
  • quenching and tempering are performed in a continuous manner by passing through a quenching furnace at 930 ° C for about 10 minutes, air-quenching and then passing through a tempering furnace at 620 ° C for about 25 minutes. , 570 ° C For 4 hours.
  • the quenching temperature of Comparative Example 12 was performed at 1100 ° C., which was conventionally performed conventionally. Other conditions are the same as in Example 15.
  • a fatigue test was carried out using the fabricated pressure ring with a piston ring fatigue tester having the operating mechanism shown in Fig. 5.
  • the product 3 with the free opening dimension expanded by cutting both ends of the opening is set on the testing machine with the ring closed to the nominal diameter, and the direction of further closing from this state
  • the eccentric cam 4 repeats the stroke corresponding to the applied stress at a cycle of 40 cycles / second, causing the ring to break.
  • the number of loads was determined. This test was repeated for samples of the same specifications while changing the load stress, so-called SN diagrams were created, and finally fatigue limit diagrams were obtained.
  • FIG. 6 shows a fatigue limit diagram. It can be seen that the fatigue limit is significantly improved in Example 15 of the present invention as compared with Comparative Example 12.
  • Example 1 From the steel materials of Example 1 (Examples 16 and 17), Example 7 (Examples 18 and 19), and Comparative Example 1 (Comparative Examples 13 and 14), through a predetermined process, a nominal diameter of 99.2 mm and a thickness of 99.2 mm (A,) 3.8mm, width (h,) 2.5mm rectangular section pressure ring (Examples 16, 18 and Comparative Example 13), nominal diameter (d,) 99.2mm, thickness (a,)
  • the two-piece oil bearing body with a saddle-shaped cross section of 2.5 mm and width (h,) 3.0 mm ('Examples 17, 19, Comparative Example 14) was machined.
  • the heat treatment of quenching and tempering and the gas nitriding were performed in the same manner as in Example 15 in Examples 16 to 19 and in Comparative Example 12 in Comparative Examples 13 to 14.
  • the manufactured pressure ring and oil ring were subjected to a 100-hour durability test under the following conditions using a 4-cylinder 3200 cc ferromagnetic monobloc nozzle diesel engine.
  • the bismuth ring made of high chromium martensite stainless steel according to the present invention is based on the technology of refining Cr carbide by adding nitrogen and the relatively low temperature. Due to the quenching, many nitrides in the nitrided layer are fine and numerous, and especially the layered grain boundary compounds in the nitrided layer have a fine microstructure, and are resistant to wear and scuffing. Because of its excellent resistance, cracking resistance and fatigue resistance, it can be used for high-speed, high-power, high-load internal combustion engines, especially recent lightweight rust-resistant monolithic diesel engines. Is possible. It can also be used effectively against fatigue of the bis-rings when using exhaust brakes on small trucks. Applicable screw rings can be conveniently used in pressure ring as well as 2-piece oil ring main bodies and 3-piece oil ring rails.

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)
  • Chemical Kinetics & Catalysis (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Abstract

L'invention concerne un segment de piston formé d'acier inoxydable martensitique à haute teneur en chrome et comprenant une couche superficielle nitrurée. Ce segment est caractérisé en ce que l'acier inoxydable présente la composition chimique suivante, en pourcentages pondéraux : C : 0,3 à 1,0 %, Cr : 14,0 à 21,0 %, N : 0,05 à 0,50 %, le total d'un ou de plusieurs des éléments Mo, V, W et Nb : 0,03 à 3,0 %, Si : 0,1 à 1,0 %, Mn : 0,1 à 1,0 %, P : au maximum 0,05 %, S : au maximum 0,05 %, le reste étant constitué de Fe et d'impuretés inévitables, et la couche de coulissement nitrurée contient des particules dures comprenant principalement des nitrures, présentant un diamètre moyen compris entre 0, 2 et 2 νm et un diamètre maximal de 7 νm, ces particules étant dispersées sur la surface à raison d'un pourcentage surfacique de 5 à 30 %. L'acier inoxydable martensitique à haute teneur en chrome présente une résistance améliorée à l'érosion, à la fissuration et à la fatigue.
PCT/JP2001/006127 2000-07-17 2001-07-16 Segment de piston presentant une resistance elevee a l'erosion, a la fissuration et a la fatigue, procede permettant de produire ce segment et combinaison segment de piston et bloc-cylindres Ceased WO2002006546A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US10/333,326 US20040040631A1 (en) 2000-07-17 2001-07-16 Piston ring excellent in resistance to scuffing, cracking and fatigue and method for producing the same, and combination of piston ring and cylinder block
EP01949987A EP1304393B1 (fr) 2000-07-17 2001-07-16 Segment de piston presentant une resistance elevee a l'erosion, a la fissuration et a la fatigue, procede permettant de produire ce segment et combinaison segment de piston et bloc-cylindres
DE60122164T DE60122164T2 (de) 2000-07-17 2001-07-16 Kolbenring mit ausgezeichneter beständigkeit gegen reibung, rissbildung und ermüdung und herstellungsverfahren dafür und kombination von kolbenriing und zylinderblock
KR10-2003-7000751A KR100507424B1 (ko) 2000-07-17 2001-07-16 내스커핑성, 내크래킹성 및 내피로성이 우수한 피스톤 링및 그 제조방법 그리고 피스톤 링과 실린더 블록의 조합
BRPI0112573-7A BR0112573B1 (pt) 2000-07-17 2001-07-16 anel de pistço.
US11/657,015 US20070187002A1 (en) 2000-07-17 2007-01-24 Piston ring having improved scuffing, cracking and fatigue resistances, and its production method, as well as combination of piston ring and cylinder block

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2000-216255 2000-07-17
JP2000216255A JP4724275B2 (ja) 2000-07-17 2000-07-17 耐スカッフィング性、耐クラッキング性及び耐疲労性に優れたピストンリング及びその製造方法

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US11/657,015 Continuation US20070187002A1 (en) 2000-07-17 2007-01-24 Piston ring having improved scuffing, cracking and fatigue resistances, and its production method, as well as combination of piston ring and cylinder block

Publications (1)

Publication Number Publication Date
WO2002006546A1 true WO2002006546A1 (fr) 2002-01-24

Family

ID=18711547

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2001/006127 Ceased WO2002006546A1 (fr) 2000-07-17 2001-07-16 Segment de piston presentant une resistance elevee a l'erosion, a la fissuration et a la fatigue, procede permettant de produire ce segment et combinaison segment de piston et bloc-cylindres

Country Status (10)

Country Link
US (2) US20040040631A1 (fr)
EP (1) EP1304393B1 (fr)
JP (1) JP4724275B2 (fr)
KR (1) KR100507424B1 (fr)
CN (1) CN1210427C (fr)
AR (1) AR029730A1 (fr)
BR (1) BR0112573B1 (fr)
DE (1) DE60122164T2 (fr)
TW (1) TW521093B (fr)
WO (1) WO2002006546A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2295777A1 (fr) * 2003-03-31 2011-03-16 Hitachi Metals, Ltd. Piston pour machine à combustion es son procédé de fabrication
CN103866202A (zh) * 2012-12-14 2014-06-18 钟庆辉 采用改性不锈钢材料制作发动机活塞环气环方法

Families Citing this family (42)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI258547B (en) * 2002-08-27 2006-07-21 Riken Co Ltd Side rails for combined oil control ring and their nitriding method
SE526805C8 (sv) * 2004-03-26 2006-09-12 Sandvik Intellectual Property Stållegering
CN100363524C (zh) * 2005-03-17 2008-01-23 上海材料研究所 一种耐腐蚀磨损的马氏体不锈钢及其制造方法及用途
JP4648094B2 (ja) * 2005-05-31 2011-03-09 株式会社神戸製鋼所 耐疲労割れ性に優れた高Ｃｒ鋳鉄およびその製造方法
JP4844902B2 (ja) 2006-04-20 2011-12-28 日立金属株式会社 内燃機関用ピストンリング材
DE102006038669A1 (de) * 2006-08-17 2008-02-28 Federal-Mogul Burscheid Gmbh Stahlwerkstoff, insbesondere zur Herstellung von Kolbenringen
JP4954644B2 (ja) * 2006-08-31 2012-06-20 日本ピストンリング株式会社 シリンダライナとピストンリングの組み合わせ
DE102008032884B4 (de) * 2008-07-14 2018-09-20 Mahle International Gmbh Ventileinrichtung, Wärmetauscher und Aufladesystem zur Aufladung einer Brennkraftmaschine mit einem Ladefluid
JP5368887B2 (ja) 2008-09-01 2013-12-18 ミネベア株式会社 マルテンサイト系ステンレス鋼および転がり軸受
BRPI0905228B1 (pt) * 2009-12-29 2017-01-24 Mahle Metal Leve Sa anel de pistão nitretado resistente à propagação de trincas
JP5676146B2 (ja) * 2010-05-25 2015-02-25 株式会社リケン 圧力リング及びその製造方法
KR101239589B1 (ko) 2010-12-27 2013-03-05 주식회사 포스코 고내식 마르텐사이트 스테인리스강 및 그 제조방법
US10053763B2 (en) 2011-06-02 2018-08-21 Aktiebolaget Skf Carbo-nitriding process for martensitic stainless steel and stainless steel article having improved corrosion resistance
KR101268736B1 (ko) 2011-06-24 2013-05-29 주식회사 포스코 마르텐사이트계 스테인리스강 및 이의 제조 방법
KR20140097390A (ko) 2011-11-30 2014-08-06 페더럴-모걸 코오포레이숀 피스톤 링 용도를 위한 고 모듈러스 내마모성 회주철
UA111115C2 (uk) 2012-04-02 2016-03-25 Ейкей Стіл Пропертіс, Інк. Рентабельна феритна нержавіюча сталь
KR102005580B1 (ko) * 2012-12-17 2019-07-30 두산인프라코어 주식회사 플랜지 타입의 슬라이딩 베어링, 이를 구비하는 슬라이딩 베어링 조립체 및 건설기계용 관절 조립체
DE102013010807A1 (de) * 2013-06-27 2014-12-31 Liebherr-Aerospace Lindenberg Gmbh Bauteil eines Luftfahrzeuges
JP6010508B2 (ja) * 2013-07-03 2016-10-19 ボーグワーナー インコーポレーテッド 摺動部材の製造方法、ならびにチェーン用リンクの製造方法および当該リンクを備えたチェーンの製造方法
US20160208372A1 (en) * 2013-08-27 2016-07-21 University Of Virginia Patent Foundation Lattice materials and structures and related methods thereof
BR102013031497A2 (pt) * 2013-12-06 2015-11-10 Mahle Int Gmbh processo de revestimento de um cilindro de um motor a combustão interna e cilindro/camisa de motor
WO2015114822A1 (fr) * 2014-01-31 2015-08-06 Ｔｐｒ株式会社 Segment de compression et matériau de base pour segment de compression
WO2015124169A1 (fr) * 2014-02-18 2015-08-27 Schmiedewerke Gröditz Gmbh Acier au chrome pour pièces de machines fortement sollicitées à l'usure, en particulier pour matrices à pelleter
JP5859048B2 (ja) * 2014-03-20 2016-02-10 サンコール株式会社 ピストンリング及びピストンリング用金属製平角線
CN104018083B (zh) * 2014-06-20 2016-01-06 重庆材料研究院有限公司 含氮不锈轴承钢及制备方法
BR102014026128B8 (pt) * 2014-10-20 2021-08-17 Mahle Int Gmbh anel de pistão e motor a combustão interna
US10196718B2 (en) * 2015-06-11 2019-02-05 Hitachi Metals, Ltd. Steel strip for cutlery
JP6139605B2 (ja) * 2015-07-17 2017-05-31 株式会社リケン ピストンリング及びその製造方法
WO2017021330A1 (fr) * 2015-08-03 2017-02-09 Mahle International Gmbh Segments de piston en acier coulé nitrurable et procédé de production
BR102015027438B8 (pt) 2015-10-29 2021-12-21 Inst De Pesquisas Tecnologicas Do Estado De Sao Paulo S/A Anéis de pistão em aços-ferramenta fundidos e seu processo de fabricação
CN106053053B (zh) * 2016-08-10 2018-08-03 三峡大学 一种活塞环疲劳试验机及疲劳试验方法
CN106119729A (zh) * 2016-08-18 2016-11-16 娄土岭 一种精密铸造轴承钢
CN106619032A (zh) * 2016-11-25 2017-05-10 天津文康科技有限公司 一种机电一体化医疗护理装置
CN106555129A (zh) * 2016-12-02 2017-04-05 机械科学研究总院青岛分院 一种含氮不锈轴承钢及制备方法
CN107326272A (zh) * 2017-05-27 2017-11-07 苏州铭晟通物资有限公司 一种钢材
JP7404792B2 (ja) 2018-12-04 2023-12-26 株式会社プロテリアル マルテンサイト系ステンレス鋼部品およびその製造方法
KR102829541B1 (ko) * 2020-02-17 2025-07-07 현대자동차주식회사 가변 오일 펌프용 아우터링 및 이의 제조방법
DE102020202259A1 (de) 2020-02-21 2021-08-26 Federal-Mogul Burscheid Gmbh Gleitelement, insbesondere Kolbenring, und Verfahren zur Herstellung desselben
CN114962460A (zh) 2021-02-25 2022-08-30 斯凯孚公司 经热处理的滚子轴承圈
CN113528941B (zh) * 2021-06-16 2025-12-23 中国兵器科学研究院宁波分院 一种含氮马氏体不锈轴承钢及其制备方法
CN114196875B (zh) * 2021-09-25 2022-10-28 浙江吉森金属科技有限公司 一种阀片用不锈钢及其热处理方法
CN115109891B (zh) * 2022-07-14 2022-12-20 中北大学 一种高碳高铬含氮马氏体不锈钢及其碳化物细化方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59162346A (ja) * 1983-02-25 1984-09-13 Hitachi Metals Ltd 圧力リング
JPS61144470A (ja) * 1984-12-19 1986-07-02 Riken Corp ピストンリング
JPH01205063A (ja) * 1988-02-10 1989-08-17 Daido Steel Co Ltd 耐摩耗ステンレス鋼部品
JPH05148593A (ja) * 1991-11-27 1993-06-15 Kanai Hiroyuki ピストンリング用線材
JPH07278758A (ja) * 1994-04-13 1995-10-24 Nippon Steel Corp エンジンガスケット用ステンレス鋼とその製造方法
JPH08134596A (ja) * 1994-11-02 1996-05-28 Nippon Steel Corp 耐応力腐食割れ特性に優れた高強度ステンレス鋼板
JPH11294584A (ja) * 1998-02-10 1999-10-29 Riken Corp 内燃機関用ピストンリング

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5154433A (en) * 1991-06-14 1992-10-13 Teikoku Piston Ring Co., Ltd. Piston ring
FR2708939B1 (fr) * 1993-08-11 1995-11-03 Sima Sa Acier martensitique à l'azote à faible teneur en carbone et son procédé de fabrication.
JP3456028B2 (ja) * 1994-10-13 2003-10-14 日立金属株式会社 加工性に優れたピストンリング材
AT402224B (de) * 1994-11-04 1997-03-25 Boehler Edelstahl Verwendung einer eisenbasislegierung sowie plungerkolben und kolbenring
JP3452354B2 (ja) * 2000-01-20 2003-09-29 日本高周波鋼業株式会社 ピストンリング用マルテンサイト系ステンレス鋼及びピストンリング用異形線

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59162346A (ja) * 1983-02-25 1984-09-13 Hitachi Metals Ltd 圧力リング
JPS61144470A (ja) * 1984-12-19 1986-07-02 Riken Corp ピストンリング
JPH01205063A (ja) * 1988-02-10 1989-08-17 Daido Steel Co Ltd 耐摩耗ステンレス鋼部品
JPH05148593A (ja) * 1991-11-27 1993-06-15 Kanai Hiroyuki ピストンリング用線材
JPH07278758A (ja) * 1994-04-13 1995-10-24 Nippon Steel Corp エンジンガスケット用ステンレス鋼とその製造方法
JPH08134596A (ja) * 1994-11-02 1996-05-28 Nippon Steel Corp 耐応力腐食割れ特性に優れた高強度ステンレス鋼板
JPH11294584A (ja) * 1998-02-10 1999-10-29 Riken Corp 内燃機関用ピストンリング

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1304393A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2295777A1 (fr) * 2003-03-31 2011-03-16 Hitachi Metals, Ltd. Piston pour machine à combustion es son procédé de fabrication
CN103866202A (zh) * 2012-12-14 2014-06-18 钟庆辉 采用改性不锈钢材料制作发动机活塞环气环方法

Also Published As

Publication number Publication date
CN1458983A (zh) 2003-11-26
KR20030025275A (ko) 2003-03-28
BR0112573B1 (pt) 2009-01-13
AR029730A1 (es) 2003-07-10
DE60122164T2 (de) 2007-10-11
KR100507424B1 (ko) 2005-08-10
DE60122164D1 (de) 2006-09-21
EP1304393A1 (fr) 2003-04-23
TW521093B (en) 2003-02-21
EP1304393B1 (fr) 2006-08-09
US20040040631A1 (en) 2004-03-04
BR0112573A (pt) 2003-07-01
JP4724275B2 (ja) 2011-07-13
CN1210427C (zh) 2005-07-13
US20070187002A1 (en) 2007-08-16
EP1304393A4 (fr) 2005-08-03
JP2002030394A (ja) 2002-01-31

Similar Documents

Publication Publication Date Title
WO2002006546A1 (fr) Segment de piston presentant une resistance elevee a l'erosion, a la fissuration et a la fatigue, procede permettant de produire ce segment et combinaison segment de piston et bloc-cylindres
KR101087562B1 (ko) 내연기관용 피스톤 및 그 제조 방법
JP5650714B2 (ja) 窒化可能な鋼製ピストンリングと鋼製シリンダーライナ及びその製造用鋳造方法
KR100701812B1 (ko) 자기 윤활성을 갖는 슬라이딩 부품용 재료 및 피스톤 링용선재
JP2002317225A (ja) ピストンリング
WO2020202406A1 (fr) Pièce carburée et son procédé de fabrication
JP5090257B2 (ja) アルミ加工用金型に適した工具鋼およびアルミ加工用金型
KR20010066864A (ko) 내연기관용 자기 윤활 피스톤 링 재료와 피스톤 링
JP4923776B2 (ja) 転がり、摺動部品およびその製造方法
WO2013187409A1 (fr) Tuyau en acier sans soudure pour ressort creux
JP2909456B2 (ja) 耐スカッフィング性に優れたピストンリング
JP3508943B2 (ja) アルミ鍛造金型用鋼
JP4066307B2 (ja) 自己潤滑性を有する内燃機関用ピストンリング材およびピストンリング
JP2013255925A (ja) 中空ばね用シームレス鋼管の製造方法
JPH03122252A (ja) 金型用鋼および金型
JP3952328B2 (ja) 耐スカッフィング性および加工性に優れたピストンリング材
CN115335544B (zh) 钢材及渗碳钢部件
KR100499753B1 (ko) 내마모성 및 피로강도가 우수한 질화강 및 습동부재
JPH0559495A (ja) ピストンリング材
JP2007321199A (ja) 耐焼付性に優れたピストンリング用鋼材、ピストンリング用異形線、並びにピストンリング
JP2005220377A (ja) 球状化後の冷間鍛造性に優れた肌焼用鋼線材・棒鋼
JPH1180910A (ja) ピストンリング材における耐スカッフィング性および加工性の改善方法
JPH11106874A (ja) 耐スカッフィング性および加工性に優れたピストンリング材
JPH09279329A (ja) 耐摩耗性に優れる温熱間鍛造用金型およびその製造方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): BR CN ID IN KR US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 44/DELNP/2003

Country of ref document: IN

WWE Wipo information: entry into national phase

Ref document number: 2001949987

Country of ref document: EP

Ref document number: 1020037000751

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 018157637

Country of ref document: CN

WWP Wipo information: published in national office

Ref document number: 1020037000751

Country of ref document: KR

WWP Wipo information: published in national office

Ref document number: 2001949987

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 10333326

Country of ref document: US

WWG Wipo information: grant in national office

Ref document number: 1020037000751

Country of ref document: KR

WWG Wipo information: grant in national office

Ref document number: 2001949987

Country of ref document: EP