WO2021095331A1 - Nitriding treatment method and nitriding treatment device - Google Patents

Nitriding treatment method and nitriding treatment device Download PDF

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Publication number
WO2021095331A1
WO2021095331A1 PCT/JP2020/033580 JP2020033580W WO2021095331A1 WO 2021095331 A1 WO2021095331 A1 WO 2021095331A1 JP 2020033580 W JP2020033580 W JP 2020033580W WO 2021095331 A1 WO2021095331 A1 WO 2021095331A1
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Prior art keywords
nitriding
sliding member
phase
test piece
gas
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PCT/JP2020/033580
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French (fr)
Japanese (ja)
Inventor
波東　久光
一矢 品川
中村　圭吾
大 兼元
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株式会社日立製作所
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Priority to DE112020004833.0T priority Critical patent/DE112020004833T5/en
Priority to US17/773,750 priority patent/US20220380881A1/en
Publication of WO2021095331A1 publication Critical patent/WO2021095331A1/en

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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
    • C23C8/24—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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
    • 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
    • C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
    • C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
    • 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
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/76—Adjusting the composition of the atmosphere
    • 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
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
    • 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
    • C21D9/0006—Details, accessories not peculiar to any of the following furnaces
    • C21D9/0018—Details, accessories not peculiar to any of the following furnaces for charging, discharging or manipulation of charge
    • 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
    • C22C38/18—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

Definitions

  • the present invention relates to a nitriding treatment method and a nitriding treatment apparatus.
  • sliding member made of steel (hereinafter referred to as “sliding member") used in a harsh wear environment such as a piston of a hydraulic pump, a cylinder of an injection molding machine, a valve, and an injection nozzle is “. Wear such as “galling” and “peeling” may occur.
  • Abrasion reduces the life of the sliding member. Therefore, it is necessary to improve the wear resistance (wear strength) of the sliding member. Further, in order to reduce the manufacturing cost of the sliding member and realize the one-piece flow manufacturing, it is necessary to process in a short time.
  • steel materials used for automobile parts, building parts, etc. are required to have strength, workability, weldability, etc.
  • Patent Document 1 describes a microstructure containing 0.05% or more nitrogen in mass% by holding the temperature at 550 ° C. or higher and the time for 1 second or longer in an atmosphere containing 0.5% or more of ammonia. A method for producing a steel material having the above is described.
  • Patent Document 2 describes a nitrification treatment method in which nitrogen is permeated and diffused into a work made of a steel material, in which induction heating is performed on the work at a frequency at which a current permeation depth is 2 mm or more.
  • An induction treatment method including spraying ammonia gas on the surface is described.
  • Patent Document 1 describes a method for producing a steel material containing 0.05% or more of nitrogen in mass%, and Patent Document 2 applies induction heating to the work on the surface of the work.
  • the denitrification treatment method of spraying ammonia gas is described.
  • Patent Document 1 describes the compound layer of the iron nitride of the ⁇ phase (Fe 2-3 N) and the ⁇ 'phase (Fe 4 N).
  • Patent Document 1 in order to improve the abrasion durability of the sliding member, the ⁇ phase (Fe 2 to 2) having a high nitrogen concentration such that the nitrogen content exceeds 4.5%. It is not stated that the compound layer of the iron nitride of 3 N) and ⁇ 'phase (Fe 4 N) needs to be formed on the steel material forming the sliding member.
  • Patent Document 1 describes that the upper limit of the nitrogen content is 4% because ductility may be impaired, and Patent Document 2 describes that the nitrogen content is 0.3 in the surface layer portion. It is stated that it is about%.
  • a compound layer of ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitrides having excellent wear resistance is applied to the steel material forming the sliding member for a short time.
  • the nitriding treatment method of the present invention uses high-frequency induction heating or energization heating, the temperature is 600 ° C. to 700 ° C., the time is 1 minute to 25 minutes, and the atmosphere of the nitride gas is used.
  • a sliding member made of steel is heated, and ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron having a nitrogen content of more than 4.5% is applied to the surface layer of the sliding member. It is characterized by forming a compound layer of nitride.
  • the nitriding apparatus of the present invention includes a nitriding chamber in which a sliding member made of steel is installed, a high-frequency heating coil installed in the nitriding chamber and heating the sliding member at high frequency.
  • a vacuum pump that vacuum exhausts the nitriding chamber, a nitriding gas cylinder that supplies nitriding gas to the nitriding chamber, a nitrogen gas cylinder that supplies nitrogen gas to the nitriding chamber, and a high frequency that is connected to the high frequency heating coil and energizes the high frequency heating coil. It is characterized by having a power source and a forced convection generating portion which is installed in a nitriding chamber and generates forced convection in the nitriding gas.
  • a compound layer of ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitrides having excellent wear resistance is applied to a steel material forming a sliding member for a short time. It is possible to provide a nitriding treatment method and a nitriding treatment apparatus for forming by reducing the amount of nitriding gas used with high thermal efficiency and with a low environmental load.
  • FIG. It is explanatory drawing explaining the nitriding processing apparatus described in Example 1.
  • FIG. It is explanatory drawing explaining the cross-sectional structure of the test piece 1 which was nitrided in Example 1.
  • FIG. It is explanatory drawing explaining the EBSD (electron backscatter diffraction method) analysis result of the test piece 1 which was nitrided in Example 1.
  • FIG. It is explanatory drawing explaining the hardness distribution in the depth direction of the test piece 1 which was nitrided in Example 1.
  • FIG. It is explanatory drawing explaining the EPMA (electron probe microanalyzer) analysis result of the test piece 1 which was nitrided in Example 1.
  • FIG. It is explanatory drawing explaining the nitriding processing apparatus described in Example 3.
  • FIG. It is explanatory drawing explaining the cross-sectional structure of the test piece 1 which was nitrided in Example 3.
  • FIG. It is explanatory drawing explaining the nitriding processing apparatus described in Example 4. It is explanatory drawing explaining the nitriding processing apparatus described in Example 5.
  • Example 1 First, the nitriding treatment apparatus described in Example 1 will be described.
  • FIG. 1 is an explanatory diagram illustrating the nitriding treatment apparatus described in the first embodiment.
  • the nitriding apparatus described in the first embodiment includes a nitriding chamber 2 in which the test piece 1 is installed, a high-frequency heating coil 3 installed in the nitriding chamber 2 for high-frequency heating of the test piece 1, and a vacuum for evacuating the nitriding chamber 2.
  • a pump 4 an ammonia gas (nitriding gas) cylinder 5 that supplies 100% concentration ammonia gas (nitriding gas) 6 to the nitriding chamber 2, a nitrogen gas cylinder 8 that supplies nitrogen gas 9 to the nitriding chamber 2, and a high frequency It has a high-frequency power source 7 which is connected to the heating coil 3 and energizes the high-frequency heating coil 3.
  • Example 1 100% concentration ammonia gas 6 is used. If a required amount (concentration) of ammonia gas 6 can be supplied to the surface of the test piece 1, ammonia gas 6 having another concentration can also be used.
  • the test piece 1 is used as the sliding member.
  • test piece 1 is installed in the nitriding chamber 2.
  • Step (2) Using the vacuum pump 4, the nitriding chamber 2 is evacuated to a pressure of about 0.5 Pa.
  • Step (3) Ammonia gas 6 is supplied from the ammonia gas cylinder 5 to the nitriding chamber 2, and the pressure in the nitriding chamber 2 is restored to 8 ⁇ 10 4 Pa. Since the concentration of ammonia gas 6 is determined by this pressure, it is preferable to restore this pressure to 2 ⁇ 10 4 Pa or more.
  • Step (4) The test piece 1 is held (heated) at a temperature of 630 ° C. for 3 minutes by a high-frequency power source 7 connected to the high-frequency heating coil 3. At this time, natural convection of ammonia gas 6 is generated on the surface of the test piece 1. Alternatively, at this time, forced convection of ammonia gas 6 is generated on the surface of the test piece 1. As a result, the nitriding potential (ammonia partial pressure / hydrogen partial pressure) in the surface layer portion (near the surface) of the test piece 1 increases, and the nitriding treatment can be performed in a state where the nitriding ability is high.
  • a high-frequency power source 7 connected to the high-frequency heating coil 3.
  • Ammonia gas 6 in a required amount (concentration) is supplied to the surface of the test piece 1 by natural convection or forced convection.
  • the ammonia gas 6 is heated in the vicinity of the test piece 1. Then, due to the temperature difference between the ammonia gas 6 heated to a temperature (600 ° C. to 700 ° C.) that contributes to the nitriding reaction and the cold unreacted ammonia gas 6 existing in the space away from the test piece 1, the ammonia gas Natural convection occurs in 6. As a result, unreacted ammonia gas 6 is supplied to the surface of the test piece 1 and nitriding is performed in a state of high nitriding ability. It is preferable to generate forced convection on the surface of the test piece 1 to supply the ammonia gas 6. As a result, the nitriding process can be performed with a higher nitriding ability.
  • Step (5) The vacuum pump 4 is used to exhaust the ammonia 6 in the nitriding chamber 2.
  • Step (6) Nitrogen gas 9 is supplied from the nitrogen gas cylinder 8 to the nitriding chamber 2, and the test piece 1 is cooled in a state of being purged with nitrogen.
  • nitriding treatment method described in Example 1 a steel material is subjected to high-frequency convection heating or energization heating at a temperature of 600 ° C. to 700 ° C., a time of 1 minute to 25 minutes, and an atmosphere of nitriding gas (ammonia gas 6). Convection of nitriding gas is generated on the surface of the sliding member (test piece 1) made of the above, unreacted nitriding gas is supplied, the sliding member is held (heated), and after this nitriding treatment, sliding is performed. It cools the member.
  • iron of ⁇ phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) having a high nitrogen concentration exceeding 4.5% (less than 11%) has a nitrogen content.
  • a compound layer of nitride is formed.
  • Example 1 high-frequency induction heating or energization heating is used, the temperature is 600 ° C. to 700 ° C., a short time (1 minute to 25 minutes), and the atmosphere of the nitride gas (ammonia gas 6).
  • the surface layer of the test piece 1 has a high nitrogen concentration of ⁇ phase (Fe 2-3 N) having a nitrogen content of more than 4.5%.
  • ⁇ 'Phase (Fe 4 N) iron nitride compound layer is formed.
  • the compound layer of the iron nitride of the ⁇ phase (Fe 2-3 N) and the ⁇ 'phase (Fe 4 N) having a high nitrogen concentration having a nitrogen content of more than 4.5% is the ⁇ phase.
  • one compound layer of ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitrides with excellent wear resistance is flown on the surface layer of the sliding member, which is suitable for manufacturing.
  • time (1 minute to 25 minutes) treatment it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load.
  • the short-time treatment suitable for the one-piece flow manufacturing can reduce the manufacturing cost of the sliding member and make the quality of the sliding member uniform even when the sliding member is mass-produced.
  • the nitriding treatment and the cooling can be carried out using one nitriding chamber 2, the nitriding treatment is carried out using the nitriding chamber 2 and the cooling is carried out using another container. , Nitriding treatment and cooling can be carried out continuously.
  • excellent wear resistance means excellent sliding characteristics and a small coefficient of friction.
  • the abrasion durability is a characteristic particularly required for a sliding member.
  • Example 1 Next, the cross-sectional structure of the test piece 1 nitrided in Example 1 will be described.
  • FIG. 2 is an explanatory view illustrating the cross-sectional structure of the test piece 1 nitrided in Example 1.
  • FIG. 2 shows a slice of the test piece 1 and an observation of the cross-sectional structure of the outer peripheral portion of the cut end. According to FIG. 2, it can be seen that the iron nitride compound layer 10 having a thickness of about 3.0 ⁇ m to 4.0 ⁇ m is formed on the surface layer portion of the test piece 1. The outermost peripheral portion is a resin layer.
  • FIG. 3 is an explanatory diagram illustrating the EBSD analysis result of the test piece 1 nitrided in Example 1.
  • FIG. 3 is an EBSD analysis of the outer peripheral portion of the test piece 1 in which the cross-sectional structure was observed.
  • ⁇ phase (Fe 2-3 N) 11, ⁇ 'phase (Fe 4 N) 12, diffusion layer ( ⁇ phase + ⁇ 'phase) 13, ⁇ phase 14 are formed on the surface layer portion of the test piece 1.
  • ⁇ phase + ⁇ 'phase Fe 4 N
  • diffusion layer ⁇ phase + ⁇ 'phase
  • the surface layer portion of the test piece 1 has a high nitrogen concentration of ⁇ phase (Fe 2-3 N) 11 and a ⁇ 'phase (Fe 4 N) 12 having a nitrogen content of more than 4.5%. It can be seen that the compound layer 10 of the iron nitride of the above is formed.
  • FIG. 4 is an explanatory diagram illustrating the hardness distribution in the depth direction of the test piece 1 nitrided in Example 1.
  • FIG. 4 shows the relationship between the distance from the surface (depth direction) and the Vickers hardness. According to FIG. 4, it can be seen that the surface layer portion of the test piece 1 is hardened by the compound layer 10 of the iron nitride, and the hardness continuously decreases from the surface toward the inside.
  • FIG. 5 is an explanatory diagram illustrating the EPMA analysis result of the test piece 1 nitrided in Example 1.
  • FIG. 5 shows the relationship between the distance from the surface (depth direction) and the nitrogen concentration (nitrogen content). According to FIG. 5, it can be seen that the nitrogen concentration of the surface layer portion of the test piece 1 is increased by the compound layer 10 of the iron nitride, and the nitrogen concentration is decreased from the surface toward the inside.
  • the iron nitride compound layer 10 of the ⁇ phase (Fe 2 to 3 N) and the ⁇ 'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by short-time treatment suitable for single-piece flow production.
  • the nitriding rate in the method B to be used was compared.
  • the heating temperature, holding time, and concentration of ammonigas 6 were the same for Method A and Method B.
  • the ⁇ phase (Fe 2-3 N) 11 and the ⁇ 'phase (Fe 4 N) of the same thickness and high nitrogen concentration exceeding 4.5% were found on the surface layer of the test piece 1.
  • the time required for the iron nitride compound layer 10 of 12 to be formed was about 1/40 of that of Method A in Method B.
  • one ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitride compound layers 10 having excellent abrasion resistance are flowed on the surface layer portion of the test piece 1. It can be seen that it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by short-time treatment suitable for production.
  • a round bar-shaped test piece A1 having a diameter of 10 mm and a length of 10 mm was formed by heating in a furnace at a temperature of 580 ° C. and nitriding treatment for 3 hours. Further, under the same conditions as in Example 1, a round bar-shaped test piece B1 having a diameter of 10 mm and a length of 10 mm was prepared.
  • a reciprocating sliding wear test was conducted on the test piece A1 and the test piece B1.
  • the friction coefficient of the test piece B1 was equal to or higher than that of the test piece A1, and the time for adhesion to occur was also equal to or higher than that of the test piece A1.
  • a piston A2 of a hydraulic pump having a diameter of 30 mm and a length of 10 mm was formed by heating in a furnace at a temperature of 580 ° C. and nitriding treatment for 3 hours. Further, a hydraulic pump B2 having a diameter of 30 mm and a length of 10 mm was produced under the same conditions as in Example 1.
  • the piston A2 of the hydraulic pump and the piston B2 of the hydraulic pump were incorporated into the hydraulic pump, and a durability test was conducted.
  • the life of the hydraulic pump piston B2 was equal to or longer than that of the hydraulic pump piston A2.
  • the surface layer portion of the sliding member is subjected to the ⁇ phase (Fe 2-3 N) and ⁇ 'phase having excellent wear resistance.
  • the compound layer 10 of the iron nitride of (Fe 4 N) can be formed by a short-time treatment suitable for one-piece flow production, with high thermal efficiency, reduced amount of nitride gas used, and with a low environmental load. I understand.
  • Example 2 the nitriding treatment was carried out by changing the temperature and time as compared with Example 1. That is, in Example 2, in the nitriding treatment method described in Example 1, the nitriding treatment was carried out by changing the temperature and time in the step (4).
  • Example 2 the nitriding treatment was carried out under four conditions: (a) 600 ° C. ⁇ 1 minute, (b) 600 ° C. ⁇ 25 minutes, (c) 700 ° C. ⁇ 1 minute, and (d) 700 ° C. ⁇ 25 minutes. did.
  • the surface layer of the test piece 1 has a high nitrogen content of more than 4.5%. It can be seen that the compound layer 10 of the iron nitride of the ⁇ phase (Fe 2-3 N) and the ⁇ 'phase (Fe 4 N) is formed.
  • test piece 1 is placed in the atmosphere of ammonia gas 6 at a temperature of 600 ° C. to 700 ° C. and a time of 1 minute to 25. Heat in minutes.
  • the iron nitride compound layer 10 of the ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N), which is excellent in wear resistance, is formed on the surface layer of the test piece 1. It can be seen that it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time treatment suitable for single-piece flow production.
  • FIG. 6 is an explanatory diagram illustrating the nitriding treatment apparatus described in the third embodiment.
  • the nitriding apparatus described in Example 3 is installed inside the nitriding chamber 2 and stirs the ammonia gas 6 supplied to the nitriding chamber 2 as compared with the nitriding apparatus described in Example 1. The difference is that it has a forced convection generator).
  • the stirrer 15 is installed below the nitriding chamber 2, but may be installed above the nitriding chamber 2.
  • the stirrer 15 to generate forced convection of the ammonia gas 6, the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, and the nitriding treatment is performed in a state where the nitriding ability is further high. can do.
  • the stirring flow rate of the stirrer 15 was 100 ml / min.
  • a straightening vane is provided in the supply path of the ammonia gas 6 so that forced convection of the ammonia gas 6 is likely to occur on the surface of the test piece 1 and the ammonia gas 6 is uniformly supplied to the surface of the test piece 1. (Not shown) may be installed. As a result, the unreacted ammonia gas 6 is supplied to the surface of the test piece 1, the nitriding rate is improved, and the nitriding treatment can be performed in a state where the nitriding ability is further high.
  • FIG. 7 is an explanatory view illustrating the cross-sectional structure of the test piece 1 nitrided in Example 3.
  • FIG. 7 is also the same as in Example 1, in which the test piece 1 is sliced into round slices, and the cross-sectional structure of the outer peripheral portion of the cut end is observed at the same magnification. According to FIG. 7, it can be seen that the iron nitride compound layer 10 having a thickness of about 5.0 ⁇ m to 6.0 ⁇ m (excluding the fine porous layer) is formed on the surface layer portion of the test piece 1.
  • the compound layer 10 is an iron nitride having a thickness of about 3.0 ⁇ m to 4.0 ⁇ m, it can be formed in a shorter time than in Example 1.
  • the nitriding rate is improved and the nitriding treatment can be performed in a state where the nitriding ability is further high.
  • the iron nitride compound layer 10 of the ⁇ phase (Fe 2-3 N) and the ⁇ 'phase (Fe 4 N) having a high nitrogen concentration exceeding 4.5% has a nitrogen content.
  • the iron nitride compound layer 10 of the ⁇ phase (Fe 2-3 N) and the ⁇ 'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for single-piece flow production.
  • the heating temperature, holding time, and concentration of ammonigas 6 were the same for Method A and Method C.
  • the ⁇ phase (Fe 2-3 N) 11 and the ⁇ 'phase (Fe 4 N) of the same thickness and high nitrogen concentration exceeding 4.5% were found on the surface layer of the test piece 1.
  • the time required for the compound layer 10 of the iron nitride of 12 to be formed was about 1/50 to 1/60 in the method C as opposed to the method A.
  • one ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitride compound layers 10 having excellent abrasion resistance are flowed on the surface layer portion of the test piece 1. It can be seen that it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for production.
  • FIG. 8 is an explanatory diagram illustrating the nitriding treatment apparatus described in the fourth embodiment.
  • the nitriding apparatus described in Example 4 is installed inside the nitriding chamber 2 and moves the test piece 1 installed in the nitriding chamber 2 up and down as compared with the nitriding apparatus described in Example 3.
  • the difference is that it has an operating unit 16 (forced convection generating unit). That is, in the fourth embodiment, the vertical movement unit 16 is installed instead of the stirrer 15.
  • the vertical movement unit 16 to generate forced convection of the ammonia gas 6, the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, and the nitriding ability is further high. It can be nitrided.
  • Example 4 although there are some differences in the thickness and nitrogen content of the iron nitride compound layer 10 as compared with Example 3, the nitrogen content is 4 in the surface layer portion of the test piece 1.
  • a compound layer 10 of ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitrides having a high nitrogen concentration exceeding 5.5% is formed.
  • Example 4 a compound layer 10 of iron nitride thicker than that of Example 1 is formed on the surface layer portion of the test piece 1. That is, the iron nitride compound layer 10 having the same thickness as that of Example 1 can be formed in a shorter time than that of Example 1.
  • the iron nitride compound layer 10 of the ⁇ phase (Fe 2 to 3 N) and the ⁇ 'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for single-piece flow production.
  • the vertical movement unit 16 may rotate together with the vertical movement.
  • FIG. 9 is an explanatory diagram illustrating the nitriding treatment apparatus according to the fifth embodiment.
  • the nitriding apparatus described in Example 5 is installed inside the nitriding chamber 2 as compared with the nitriding apparatus described in Example 3, and the test piece 1 installed in the nitriding chamber 2 is rotated.
  • the difference is that it has an operating unit 17 (forced convection generating unit). That is, in the fifth embodiment, the rotary operation unit 17 is installed instead of the stirrer 15.
  • the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, and the nitriding ability is further high. It can be nitrided.
  • Example 5 although there are some differences in the thickness and nitrogen content of the iron nitride compound layer 10 as compared with Example 3, the nitrogen content is 4 in the surface layer portion of the test piece 1.
  • a compound layer 10 of ⁇ -phase (Fe 2-3 N) and ⁇ 'phase (Fe 4 N) iron nitrides having a high nitrogen concentration exceeding 5.5% is formed.
  • Example 5 a compound layer 10 of iron nitride thicker than that of Example 1 is formed on the surface layer portion of the test piece 1. That is, the iron nitride compound layer 10 having the same thickness as that of Example 1 can be formed in a shorter time than that of Example 1.
  • the iron nitride compound layer 10 of the ⁇ phase (Fe 2 to 3 N) and the ⁇ 'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for single-piece flow production.
  • the rotation operation unit 17 may move up and down together with the rotation operation.
  • wings may be installed on the rotary motion unit 17.
  • the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, the nitriding rate is improved, and the nitriding treatment can be performed in a state where the nitriding ability is further high.
  • the present invention is not limited to the above-described examples, and includes various modifications.
  • the above-described embodiment has been specifically described in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations.

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Abstract

The present invention provides a nitriding treatment method for forming an iron nitride compound layer composed of an ε-phase (Fe2-3N) and a γ'-phase (Fe4N) and having excellent durability against abrasion on an iron steel material that forms a sliding member, within a short treatment time, with high thermal efficiency, using a nitriding gas in a reduced amount, and under a low environmental load. The nitriding treatment method of the present invention is characterized by heating a sliding member comprising an iron steel material utilizing frequency induction heating or electrical heating at a temperature of 600℃ to 700℃ for a time of 1 to 25 minutes under a nitrogen gas atmosphere to form an iron nitride compound layer composed of an ε-phase (Fe2-3N) and a γ'-phase (Fe4N) and having a nitrogen content of more than 4.5% on a surface layer part of the sliding member.

Description

窒化処理方法及び窒化処理装置Nitriding processing method and nitriding processing equipment
　本発明は、窒化処理方法及び窒化処理装置に関する。 The present invention relates to a nitriding treatment method and a nitriding treatment apparatus.
　油圧ポンプのピストン、射出成形機のシリンダー、バルブ、インジェクションノズルなどの過酷な摩損環境下で使用される鉄鋼材からなる摺動部材（以下、「摺動部材」と呼称する）の表面は、「かじり」や「はく離」などの摩損が発生する場合がある。 The surface of a sliding member made of steel (hereinafter referred to as "sliding member") used in a harsh wear environment such as a piston of a hydraulic pump, a cylinder of an injection molding machine, a valve, and an injection nozzle is ". Wear such as "galling" and "peeling" may occur.
　摩損は、摺動部材の寿命を減少させる。そこで、摺動部材の摩損耐久性（摩損強度）を向上させる必要がある。また、摺動部材の製造コストを低減し、１個流し製造を実現するため、短時間で処理する必要がある。 Abrasion reduces the life of the sliding member. Therefore, it is necessary to improve the wear resistance (wear strength) of the sliding member. Further, in order to reduce the manufacturing cost of the sliding member and realize the one-piece flow manufacturing, it is necessary to process in a short time.
　一方、自動車部材、建築部材などに使用される鉄鋼材には、強度、加工性、溶接性などが必要である。 On the other hand, steel materials used for automobile parts, building parts, etc. are required to have strength, workability, weldability, etc.
　このような鉄鋼材に関する技術分野の背景技術として、特開２００５－１４６３２１号公報（特許文献１）がある。特許文献１には、アンモニアを０．５％以上含む雰囲気中、温度が５５０℃以上、時間が１秒以上、保持することにより、質量％で、０．０５％以上の窒素を含有させる微細組織を有する鉄鋼材の製造方法が記載されている。 As a background technology in the technical field related to such steel materials, there is Japanese Patent Application Laid-Open No. 2005-146321 (Patent Document 1). Patent Document 1 describes a microstructure containing 0.05% or more nitrogen in mass% by holding the temperature at 550 ° C. or higher and the time for 1 second or longer in an atmosphere containing 0.5% or more of ammonia. A method for producing a steel material having the above is described.
　また、浸窒処理方法として、特開２０１７－１３７５４７号公報（特許文献２）がある。特許文献２には、鉄鋼材からなるワークに窒素を浸透拡散させる浸窒処理方法であって、ワークに対して、電流浸透深さが２ｍｍ以上になる周波数で誘導加熱を実施すること、ワークの表面にアンモニアガスを吹き付けること、を含む浸窒処理方法が記載されている。 Further, as an immersion treatment method, there is Japanese Patent Application Laid-Open No. 2017-137547 (Patent Document 2). Patent Document 2 describes a nitrification treatment method in which nitrogen is permeated and diffused into a work made of a steel material, in which induction heating is performed on the work at a frequency at which a current permeation depth is 2 mm or more. An induction treatment method including spraying ammonia gas on the surface is described.
特開２００５－１４６３２１号公報Japanese Unexamined Patent Publication No. 2005-146321 特開２０１７－１３７５４７号公報JP-A-2017-137547
　特許文献１には、質量％で、０．０５％以上の窒素を含有させる鉄鋼材の製造方法が記載され、特許文献２には、ワークに対して、誘導加熱を実施し、ワークの表面にアンモニアガスを吹き付ける浸窒処理方法が記載されている。 Patent Document 1 describes a method for producing a steel material containing 0.05% or more of nitrogen in mass%, and Patent Document 2 applies induction heating to the work on the surface of the work. The denitrification treatment method of spraying ammonia gas is described.
　しかし、特許文献１及び特許文献２には、いずれにも、ε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層について、記載されていない。 However, neither Patent Document 1 nor Patent Document 2 describes the compound layer of the iron nitride of the ε phase (Fe 2-3 N) and the γ'phase (Fe 4 N).
　また、特許文献１及び特許文献２には、いずれにも、摺動部材の摩損耐久性を向上させるため、窒素含有量が４．５％を超えるような高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、摺動部材を形成する鉄鋼材に、形成する必要がある旨は、記載されていない。特に、特許文献１には、延性を損ねる場合があるため、窒素含有量の上限を４％とすることが記載され、また、特許文献２には、窒素含有量が、表層部で０．３％程度であることが、記載されている。 Further, in both Patent Document 1 and Patent Document 2, in order to improve the abrasion durability of the sliding member, the ε phase (Fe 2 to 2) having a high nitrogen concentration such that the nitrogen content exceeds 4.5%. It is not stated that the compound layer of the iron nitride of 3 N) and γ'phase (Fe 4 N) needs to be formed on the steel material forming the sliding member. In particular, Patent Document 1 describes that the upper limit of the nitrogen content is 4% because ductility may be impaired, and Patent Document 2 describes that the nitrogen content is 0.3 in the surface layer portion. It is stated that it is about%.
　そこで、本発明は、摺動部材を形成する鉄鋼材に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、短時間処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成する窒化処理方法及び窒化処理装置を提供する。 Therefore, in the present invention, a compound layer of ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitrides having excellent wear resistance is applied to the steel material forming the sliding member for a short time. Provided are a nitriding treatment method and a nitriding treatment apparatus for forming by reducing the amount of nitriding gas used in the treatment with high thermal efficiency and with a low environmental load.
　上記した課題を解決するため、本発明の窒化処理方法は、高周波誘導加熱又は通電加熱を使用し、温度が６００℃～７００℃で、時間が１分～２５分で、窒化ガスの雰囲気下で、鉄鋼材からなる摺動部材を加熱し、摺動部材の表層部に、窒素含有量が４．５％を超えるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を形成することを特徴とする。 In order to solve the above-mentioned problems, the nitriding treatment method of the present invention uses high-frequency induction heating or energization heating, the temperature is 600 ° C. to 700 ° C., the time is 1 minute to 25 minutes, and the atmosphere of the nitride gas is used. , A sliding member made of steel is heated, and ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron having a nitrogen content of more than 4.5% is applied to the surface layer of the sliding member. It is characterized by forming a compound layer of nitride.
　また、上記した課題を解決するため、本発明の窒化処理装置は、鉄鋼材からなる摺動部材を設置する窒化チャンバと、窒化チャンバに設置され、摺動部材を高周波加熱する高周波加熱コイルと、窒化チャンバを真空排気する真空ポンプと、窒化チャンバに、窒化ガスを供給する窒化ガスボンベと、窒化チャンバに、窒素ガスを供給する窒素ガスボンベと、高周波加熱コイルに接続され、高周波加熱コイルに通電する高周波電源と、窒化チャンバに設置され、窒化ガスに強制対流を発生させる強制対流発生部と、を有することを特徴とする。 Further, in order to solve the above-mentioned problems, the nitriding apparatus of the present invention includes a nitriding chamber in which a sliding member made of steel is installed, a high-frequency heating coil installed in the nitriding chamber and heating the sliding member at high frequency. A vacuum pump that vacuum exhausts the nitriding chamber, a nitriding gas cylinder that supplies nitriding gas to the nitriding chamber, a nitrogen gas cylinder that supplies nitrogen gas to the nitriding chamber, and a high frequency that is connected to the high frequency heating coil and energizes the high frequency heating coil. It is characterized by having a power source and a forced convection generating portion which is installed in a nitriding chamber and generates forced convection in the nitriding gas.
　本発明によれば、摺動部材を形成する鉄鋼材に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、短時間処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成する窒化処理方法及び窒化処理装置を提供することができる。 According to the present invention, a compound layer of ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitrides having excellent wear resistance is applied to a steel material forming a sliding member for a short time. It is possible to provide a nitriding treatment method and a nitriding treatment apparatus for forming by reducing the amount of nitriding gas used with high thermal efficiency and with a low environmental load.
　なお、上記した以外の課題、構成及び効果については、下記する実施例の説明により、明らかにされる。 Issues, configurations and effects other than those mentioned above will be clarified by the explanation of the examples below.
実施例１に記載する窒化処理装置を説明する説明図である。It is explanatory drawing explaining the nitriding processing apparatus described in Example 1. FIG. 実施例１にて窒化処理された試験片１の断面組織を説明する説明図である。It is explanatory drawing explaining the cross-sectional structure of the test piece 1 which was nitrided in Example 1. FIG. 実施例１にて窒化処理された試験片１のＥＢＳＤ（電子線後方散乱回折法）分析結果を説明する説明図である。It is explanatory drawing explaining the EBSD (electron backscatter diffraction method) analysis result of the test piece 1 which was nitrided in Example 1. FIG. 実施例１にて窒化処理された試験片１の深さ方向の硬さ分布を説明する説明図である。It is explanatory drawing explaining the hardness distribution in the depth direction of the test piece 1 which was nitrided in Example 1. FIG. 実施例１にて窒化処理された試験片１のＥＰＭＡ（電子線マイクロアナライザ）分析結果を説明する説明図である。It is explanatory drawing explaining the EPMA (electron probe microanalyzer) analysis result of the test piece 1 which was nitrided in Example 1. FIG. 実施例３に記載する窒化処理装置を説明する説明図である。It is explanatory drawing explaining the nitriding processing apparatus described in Example 3. 実施例３にて窒化処理された試験片１の断面組織を説明する説明図である。It is explanatory drawing explaining the cross-sectional structure of the test piece 1 which was nitrided in Example 3. FIG. 実施例４に記載する窒化処理装置を説明する説明図である。It is explanatory drawing explaining the nitriding processing apparatus described in Example 4. 実施例５に記載する窒化処理装置を説明する説明図である。It is explanatory drawing explaining the nitriding processing apparatus described in Example 5.
　以下、図面を使用して、本発明の実施例を説明する。なお、実質的に同一又は類似の構成には同一の符号を付し、説明が重複する場合には、その説明を省略する場合がある。 Hereinafter, examples of the present invention will be described with reference to the drawings. In addition, substantially the same or similar configurations are designated by the same reference numerals, and when the explanations are duplicated, the explanations may be omitted.
　まず、実施例１に記載する窒化処理装置を説明する。 First, the nitriding treatment apparatus described in Example 1 will be described.
　図１は、実施例１に記載する窒化処理装置を説明する説明図である。 FIG. 1 is an explanatory diagram illustrating the nitriding treatment apparatus described in the first embodiment.
　実施例１に記載する窒化処理装置は、試験片１を設置する窒化チャンバ２と、窒化チャンバ２に設置され、試験片１を高周波加熱する高周波加熱コイル３と、窒化チャンバ２を真空排気する真空ポンプ４と、窒化チャンバ２に、１００％濃度のアンモニアガス（窒化ガス）６を供給するアンモニアガス（窒化ガス）ボンベ５と、窒化チャンバ２に、窒素ガス９を供給する窒素ガスボンベ８と、高周波加熱コイル３に接続され、高周波加熱コイル３に通電する高周波電源７と、を有する。 The nitriding apparatus described in the first embodiment includes a nitriding chamber 2 in which the test piece 1 is installed, a high-frequency heating coil 3 installed in the nitriding chamber 2 for high-frequency heating of the test piece 1, and a vacuum for evacuating the nitriding chamber 2. A pump 4, an ammonia gas (nitriding gas) cylinder 5 that supplies 100% concentration ammonia gas (nitriding gas) 6 to the nitriding chamber 2, a nitrogen gas cylinder 8 that supplies nitrogen gas 9 to the nitriding chamber 2, and a high frequency It has a high-frequency power source 7 which is connected to the heating coil 3 and energizes the high-frequency heating coil 3.
　なお、実施例１では、１００％濃度のアンモニアガス６を使用する。試験片１の表面に、必要な量（濃度）のアンモニアガス６を供給することができれば、他の濃度のアンモニアガス６も使用することができる。 In Example 1, 100% concentration ammonia gas 6 is used. If a required amount (concentration) of ammonia gas 6 can be supplied to the surface of the test piece 1, ammonia gas 6 having another concentration can also be used.
　また、実施例１では、摺動部材として、試験片１を使用する。試験片１の材料として、一般的な、質量％で、Ｃ：０．３３～０．３８％、Ｓｉ：０．１５～０．３５％、Ｍｎ：０．６０～０．９０％、Ｐ：０．０３以下、Ｓ：０．０３以下、Ｎｉ：０．２５以下、Ｃｒ：０．９０～１．２０％、Ｍｏ：０．１５～０．３０％を含有するクロムモリブレン鉄鋼材を使用し、直径１０ｍｍ×長さ５０ｍｍの丸棒状の試験片１を形成する。 Further, in the first embodiment, the test piece 1 is used as the sliding member. As a general material for the test piece 1, in mass%, C: 0.33 to 0.38%, Si: 0.15 to 0.35%, Mn: 0.60 to 0.90%, P: Uses chromium molybdenum steel containing 0.03 or less, S: 0.03 or less, Ni: 0.25 or less, Cr: 0.90 to 1.20%, Mo: 0.15 to 0.30%. Then, a round bar-shaped test piece 1 having a diameter of 10 mm and a length of 50 mm is formed.
　次に、実施例１に記載する窒化処理方法を説明する。 Next, the nitriding treatment method described in Example 1 will be described.
　工程（１）試験片１を、窒化チャンバ２に、設置する。 Process (1) The test piece 1 is installed in the nitriding chamber 2.
　工程（２）真空ポンプ４を使用して、窒化チャンバ２を、０．５Ｐａ程度の圧力に、真空排気する。 Step (2) Using the vacuum pump 4, the nitriding chamber 2 is evacuated to a pressure of about 0.5 Pa.
　工程（３）アンモニアガスボンベ５からアンモニアガス６を、窒化チャンバ２に供給し、窒化チャンバ２の圧力を、８×１０４Ｐａになるように、復圧する。なお、この圧力により、アンモニアガス６の濃度が決定されるため、この圧力を、２×１０４Ｐａ以上になるように、復圧することが好ましい。 Step (3) Ammonia gas 6 is supplied from the ammonia gas cylinder 5 to the nitriding chamber 2, and the pressure in the nitriding chamber 2 is restored to 8 × 10 4 Pa. Since the concentration of ammonia gas 6 is determined by this pressure, it is preferable to restore this pressure to 2 × 10 4 Pa or more.
　工程（４）高周波加熱コイル３に接続される高周波電源７により、試験片１を、温度６３０℃、時間３分間、保持（加熱）する。この際、試験片１の表面には、アンモニアガス６の自然対流が発生する。又は、この際、試験片１の表面に、アンモニアガス６の強制対流を発生させる。これにより、試験片１の表層部（表面近傍）における窒化ポテンシャル（アンモニア分圧／水素分圧）が上昇し、窒化能力が高い状態で窒化処理することができる。 Step (4) The test piece 1 is held (heated) at a temperature of 630 ° C. for 3 minutes by a high-frequency power source 7 connected to the high-frequency heating coil 3. At this time, natural convection of ammonia gas 6 is generated on the surface of the test piece 1. Alternatively, at this time, forced convection of ammonia gas 6 is generated on the surface of the test piece 1. As a result, the nitriding potential (ammonia partial pressure / hydrogen partial pressure) in the surface layer portion (near the surface) of the test piece 1 increases, and the nitriding treatment can be performed in a state where the nitriding ability is high.
　試験片１の表面には、自然対流又は強制対流により、必要な量（濃度）のアンモニアガス６を供給する。なお、更に窒化能力が高い状態で窒化処理するため、強制対流により、試験片１の表面に、アンモニアガス６を供給することが好ましい。 Ammonia gas 6 in a required amount (concentration) is supplied to the surface of the test piece 1 by natural convection or forced convection. In addition, in order to carry out the nitriding treatment in a state where the nitriding ability is further high, it is preferable to supply the ammonia gas 6 to the surface of the test piece 1 by forced convection.
　つまり、試験片１の近傍で、アンモニアガス６が加熱される。そして、窒化反応に寄与する温度（６００℃～７００℃）まで加熱されたアンモニアガス６と、試験片１から離れた空間に存在する冷たい未反応のアンモニアガス６と、の温度差により、アンモニアガス６に自然対流が発生する。これにより、試験片１の表面には、未反応のアンモニアガス６が供給され、窒化能力が高い状態で窒化処理される。なお、試験片１の表面には、強制対流を発生させて、アンモニアガス６を供給することが好ましい。これにより、更に窒化能力が高い状態で窒化処理することができる。 That is, the ammonia gas 6 is heated in the vicinity of the test piece 1. Then, due to the temperature difference between the ammonia gas 6 heated to a temperature (600 ° C. to 700 ° C.) that contributes to the nitriding reaction and the cold unreacted ammonia gas 6 existing in the space away from the test piece 1, the ammonia gas Natural convection occurs in 6. As a result, unreacted ammonia gas 6 is supplied to the surface of the test piece 1 and nitriding is performed in a state of high nitriding ability. It is preferable to generate forced convection on the surface of the test piece 1 to supply the ammonia gas 6. As a result, the nitriding process can be performed with a higher nitriding ability.
　工程（５）真空ポンプ４を使用して、窒化チャンバ２のアンモニア６を排気する。 Step (5) The vacuum pump 4 is used to exhaust the ammonia 6 in the nitriding chamber 2.
　工程（６）窒素ガスボンベ８から窒素ガス９を、窒化チャンバ２に供給し、窒素パージした状態で、試験片１を冷却する。 Step (6) Nitrogen gas 9 is supplied from the nitrogen gas cylinder 8 to the nitriding chamber 2, and the test piece 1 is cooled in a state of being purged with nitrogen.
　つまり、実施例１に記載する窒化処理方法は、高周波誘導加熱又は通電加熱により、温度が６００℃～７００℃、時間が１分～２５分、窒化ガス（アンモニアガス６）の雰囲気下、鉄鋼材からなる摺動部材（試験片１）の表面に、窒化ガスの対流を発生させて、未反応の窒化ガスを供給し、摺動部材を保持（加熱）し、この窒化処理の後、摺動部材を冷却するものである。 That is, in the nitriding treatment method described in Example 1, a steel material is subjected to high-frequency convection heating or energization heating at a temperature of 600 ° C. to 700 ° C., a time of 1 minute to 25 minutes, and an atmosphere of nitriding gas (ammonia gas 6). Convection of nitriding gas is generated on the surface of the sliding member (test piece 1) made of the above, unreacted nitriding gas is supplied, the sliding member is held (heated), and after this nitriding treatment, sliding is performed. It cools the member.
　そして、摺動部材の表層部に、窒素含有量が４．５％を超える（１１％未満の）高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、形成する。 Then, on the surface layer of the sliding member, iron of ε phase (Fe 2-3 N) and γ'phase (Fe 4 N) having a high nitrogen concentration exceeding 4.5% (less than 11%) has a nitrogen content. A compound layer of nitride is formed.
　このように実施例１では、高周波誘導加熱又は通電加熱を使用し、温度が６００℃～７００℃で、短時間（１分～２５分）で、窒化ガス（アンモニアガス６）の雰囲気下で、試験片１（摺動部材を形成する鉄鋼材）を加熱することにより、試験片１の表層部に、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、形成する。 As described above, in Example 1, high-frequency induction heating or energization heating is used, the temperature is 600 ° C. to 700 ° C., a short time (1 minute to 25 minutes), and the atmosphere of the nitride gas (ammonia gas 6). By heating the test piece 1 (the steel material forming the sliding member), the surface layer of the test piece 1 has a high nitrogen concentration of ε phase (Fe 2-3 N) having a nitrogen content of more than 4.5%. , Γ'Phase (Fe 4 N) iron nitride compound layer is formed.
　なお、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層は、具体的には、ε相、ε相＋γ‘相、γ‘相＋ε相、γ‘相からなる。 Specifically, the compound layer of the iron nitride of the ε phase (Fe 2-3 N) and the γ'phase (Fe 4 N) having a high nitrogen concentration having a nitrogen content of more than 4.5% is the ε phase. , Ε phase + γ'phase, γ'phase + ε phase, γ'phase.
　これにより、摺動部材の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、１個流し製造に適する短時間（１分～２５分）処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができる。 As a result, one compound layer of ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitrides with excellent wear resistance is flown on the surface layer of the sliding member, which is suitable for manufacturing. By time (1 minute to 25 minutes) treatment, it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load.
　更に、１個流し製造に適する短時間処理により、摺動部材の製造コストを低減すると共に、摺動部材を量産する場合であっても、摺動部材の品質を均一にすることができる。 Further, the short-time treatment suitable for the one-piece flow manufacturing can reduce the manufacturing cost of the sliding member and make the quality of the sliding member uniform even when the sliding member is mass-produced.
　なお、１個流し製造を実現するためには、摺動部材の形状や大きさに依存するが、１分～２５分の短時間で、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を、形成する必要がある。 It should be noted that, although it depends on the shape and size of the sliding member in order to realize the one-piece flow manufacturing, the ε phase (Fe 2-3 N) having excellent wear resistance in a short time of 1 minute to 25 minutes. , Γ'Phase (Fe 4 N) iron nitride compound layer needs to be formed.
　なお、窒化処理と冷却とを、一つの窒化チャンバ２を使用して、実施することもできるが、窒化チャンバ２を使用して窒化処理を実施し、別の容器を使用して冷却を実施し、窒化処理と冷却とを連続して実施することもできる。 Although the nitriding treatment and the cooling can be carried out using one nitriding chamber 2, the nitriding treatment is carried out using the nitriding chamber 2 and the cooling is carried out using another container. , Nitriding treatment and cooling can be carried out continuously.
　また、摩損耐久性に優れるとは、摺動特性に優れることであり、摩擦係数が小さいことである。そして、摩損耐久性は、特に、摺動部材に要求される特性である。 In addition, excellent wear resistance means excellent sliding characteristics and a small coefficient of friction. The abrasion durability is a characteristic particularly required for a sliding member.
　次に、実施例１にて窒化処理された試験片１の断面組織を説明する。 Next, the cross-sectional structure of the test piece 1 nitrided in Example 1 will be described.
　図２は、実施例１にて窒化処理された試験片１の断面組織を説明する説明図である。 FIG. 2 is an explanatory view illustrating the cross-sectional structure of the test piece 1 nitrided in Example 1.
　図２は、試験片１を輪切りにし、その切り口の外周部の断面組織を観察したものである。図２によれば、試験片１の表層部に、厚さ３．０μｍ～４．０μｍ程度の鉄窒化物の化合物層１０が形成されていることが分かる。なお、最外周部は、樹脂層である。 FIG. 2 shows a slice of the test piece 1 and an observation of the cross-sectional structure of the outer peripheral portion of the cut end. According to FIG. 2, it can be seen that the iron nitride compound layer 10 having a thickness of about 3.0 μm to 4.0 μm is formed on the surface layer portion of the test piece 1. The outermost peripheral portion is a resin layer.
　次に、実施例１にて窒化処理された試験片１のＥＢＳＤ分析結果を説明する。 Next, the EBSD analysis result of the test piece 1 nitrided in Example 1 will be described.
　図３は、実施例１にて窒化処理された試験片１のＥＢＳＤ分析結果を説明する説明図である。 FIG. 3 is an explanatory diagram illustrating the EBSD analysis result of the test piece 1 nitrided in Example 1.
　図３は、断面組織を観察した試験片１の外周部をＥＢＳＤ分析したものである。図３によれば、試験片１の表層部に、ε相（Ｆｅ２～３Ｎ）１１、γ‘相（Ｆｅ４Ｎ）１２、拡散層（α相＋γ‘相）１３、α相１４が、形成されていることが分かる。 FIG. 3 is an EBSD analysis of the outer peripheral portion of the test piece 1 in which the cross-sectional structure was observed. According to FIG. 3, on the surface layer portion of the test piece 1, ε phase (Fe 2-3 N) 11, γ'phase (Fe 4 N) 12, diffusion layer (α phase + γ'phase) 13, α phase 14 are formed. , It can be seen that it is formed.
　そして、図３によれば、試験片１の表層部に、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）１１、γ‘相（Ｆｅ４Ｎ）１２の鉄窒化物の化合物層１０が、形成されていることが分かる。 Then, according to FIG. 3, the surface layer portion of the test piece 1 has a high nitrogen concentration of ε phase (Fe 2-3 N) 11 and a γ'phase (Fe 4 N) 12 having a nitrogen content of more than 4.5%. It can be seen that the compound layer 10 of the iron nitride of the above is formed.
　次に、実施例１にて窒化処理された試験片１の深さ方向の硬さ分布を説明する。 Next, the hardness distribution in the depth direction of the nitriding test piece 1 in Example 1 will be described.
　図４は、実施例１にて窒化処理された試験片１の深さ方向の硬さ分布を説明する説明図である。 FIG. 4 is an explanatory diagram illustrating the hardness distribution in the depth direction of the test piece 1 nitrided in Example 1.
　図４は、表面からの距離（深さ方向）とビッカース硬さとの関係を示したものである。
図４によれば、試験片１の表層部は、鉄窒化物の化合物層１０により硬化し、表面から内部に向かうに従い、連続的に、硬さが低下していることが分かる。 FIG. 4 shows the relationship between the distance from the surface (depth direction) and the Vickers hardness.
According to FIG. 4, it can be seen that the surface layer portion of the test piece 1 is hardened by the compound layer 10 of the iron nitride, and the hardness continuously decreases from the surface toward the inside.
　次に、実施例１にて窒化処理された試験片１のＥＰＭＡ分析結果を説明する。 Next, the EPMA analysis result of the nitriding test piece 1 in Example 1 will be described.
　図５は、実施例１にて窒化処理された試験片１のＥＰＭＡ分析結果を説明する説明図である。 FIG. 5 is an explanatory diagram illustrating the EPMA analysis result of the test piece 1 nitrided in Example 1.
　図５は、表面からの距離（深さ方向）と窒素濃度（窒素含有量）との関係を示したものである。図５によれば、試験片１の表層部は、鉄窒化物の化合物層１０により、窒素濃度が増加し、表面から内部に向かうに従い、窒素濃度が低下していることが分かる。 FIG. 5 shows the relationship between the distance from the surface (depth direction) and the nitrogen concentration (nitrogen content). According to FIG. 5, it can be seen that the nitrogen concentration of the surface layer portion of the test piece 1 is increased by the compound layer 10 of the iron nitride, and the nitrogen concentration is decreased from the surface toward the inside.
　このように実施例１によれば、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができる。 As described above, according to the first embodiment, the iron nitride compound layer 10 of the ε phase (Fe 2 to 3 N) and the γ'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by short-time treatment suitable for single-piece flow production.
　また、炉加熱のように、アンモニアガス６の全体が加熱される方式Ａにおける窒化速度と、高周波加熱コイル３を使用した高周波誘導加熱のように、試験片１の近傍で、アンモニアガス６が加熱される方式Ｂにおける窒化速度と、を比較した。 Further, the nitriding rate in the method A in which the entire ammonia gas 6 is heated like furnace heating, and the ammonia gas 6 is heated in the vicinity of the test piece 1 like the high frequency induction heating using the high frequency heating coil 3. The nitriding rate in the method B to be used was compared.
　なお、加熱温度、保持時間、アンモニガス６の濃度を、方式Ａと方式Ｂとで同じとした。 The heating temperature, holding time, and concentration of ammonigas 6 were the same for Method A and Method B.
　比較した結果、試験片１の表層部に、同じ厚さの、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）１１、γ‘相（Ｆｅ４Ｎ）１２の鉄窒化物の化合物層１０が、形成されるのに要する時間は、方式Ａに対して方式Ｂは、約１／４０であった。 As a result of comparison, on the surface layer of the test piece 1, the ε phase (Fe 2-3 N) 11 and the γ'phase (Fe 4 N) of the same thickness and high nitrogen concentration exceeding 4.5% were found. The time required for the iron nitride compound layer 10 of 12 to be formed was about 1/40 of that of Method A in Method B.
　つまり、方式Ｂは、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができることが分かる。 That is, in the method B, one ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitride compound layers 10 having excellent abrasion resistance are flowed on the surface layer portion of the test piece 1. It can be seen that it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by short-time treatment suitable for production.
　また、炉加熱で、温度５８０℃で、時間３時間で窒化処理を実施した直径１０ｍｍ×長さ１０ｍｍの丸棒状の試験片Ａ１を形成した。更に、実施例１と同じ条件で、直径１０ｍｍ×長さ１０ｍｍの丸棒状の試験片Ｂ１を作成した。 Further, a round bar-shaped test piece A1 having a diameter of 10 mm and a length of 10 mm was formed by heating in a furnace at a temperature of 580 ° C. and nitriding treatment for 3 hours. Further, under the same conditions as in Example 1, a round bar-shaped test piece B1 having a diameter of 10 mm and a length of 10 mm was prepared.
　試験片Ａ１と試験片Ｂ１とについて、往復摺動摩耗試験を実施した。試験片Ａ１に対して試験片Ｂ１は、摩擦係数は同等以上であり、凝着が起こる時間も同等以上であった。 A reciprocating sliding wear test was conducted on the test piece A1 and the test piece B1. The friction coefficient of the test piece B1 was equal to or higher than that of the test piece A1, and the time for adhesion to occur was also equal to or higher than that of the test piece A1.
　これにより、実施例１の条件で形成される摺動部材は、摺動部材としての摩損耐久性を有することが確認された。 From this, it was confirmed that the sliding member formed under the conditions of Example 1 has abrasion durability as a sliding member.
　また、炉加熱で、温度５８０℃で、時間３時間で窒化処理を実施した直径３０ｍｍ×長さ１０ｍｍの油圧ポンプのピストンＡ２を形成した。更に、実施例１と同じ条件で、直径３０ｍｍ×長さ１０ｍｍの油圧ポンプＢ２を作成した。 Further, a piston A2 of a hydraulic pump having a diameter of 30 mm and a length of 10 mm was formed by heating in a furnace at a temperature of 580 ° C. and nitriding treatment for 3 hours. Further, a hydraulic pump B2 having a diameter of 30 mm and a length of 10 mm was produced under the same conditions as in Example 1.
　油圧ポンプのピストンＡ２と油圧ポンプのピストンＢ２とを、油圧ポンプに組み込んで、耐久性試験を実施した。油圧ポンプのピストンＡ２に対して油圧ポンプのピストンＢ２は、寿命は同等以上であった。 The piston A2 of the hydraulic pump and the piston B2 of the hydraulic pump were incorporated into the hydraulic pump, and a durability test was conducted. The life of the hydraulic pump piston B2 was equal to or longer than that of the hydraulic pump piston A2.
　これにより、実施例１の条件で形成される摺動部材は、摺動部材としての摩損耐久性を有することが確認された。 From this, it was confirmed that the sliding member formed under the conditions of Example 1 has abrasion durability as a sliding member.
　このように、実施例１に記載する窒化処理を、摺動部材に、実施することにより、摺動部材の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができることが分かる。 As described above, by performing the nitriding treatment described in Example 1 on the sliding member, the surface layer portion of the sliding member is subjected to the ε phase (Fe 2-3 N) and γ'phase having excellent wear resistance. The compound layer 10 of the iron nitride of (Fe 4 N) can be formed by a short-time treatment suitable for one-piece flow production, with high thermal efficiency, reduced amount of nitride gas used, and with a low environmental load. I understand.
　実施例２は、実施例１と比較して、温度と時間とを変化させ、窒化処理を実施した。つまり、実施例２は、実施例１に記載する窒化処理方法において、工程（４）における温度と時間とを変化させ、窒化処理を実施した。 In Example 2, the nitriding treatment was carried out by changing the temperature and time as compared with Example 1. That is, in Example 2, in the nitriding treatment method described in Example 1, the nitriding treatment was carried out by changing the temperature and time in the step (4).
　実施例２では、（ア）６００℃×１分、（イ）６００℃×２５分、（ウ）７００℃×１分、（エ）７００℃×２５分の４つの条件で、窒化処理を実施した。 In Example 2, the nitriding treatment was carried out under four conditions: (a) 600 ° C. × 1 minute, (b) 600 ° C. × 25 minutes, (c) 700 ° C. × 1 minute, and (d) 700 ° C. × 25 minutes. did.
　いずれの条件においても、鉄窒化物の化合物層１０の厚さや窒素含有量に多少の差異は認められるものの、試験片１の表層部に、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０が、形成されていることが分かる。 Under all conditions, although there are some differences in the thickness and nitrogen content of the iron nitride compound layer 10, the surface layer of the test piece 1 has a high nitrogen content of more than 4.5%. It can be seen that the compound layer 10 of the iron nitride of the ε phase (Fe 2-3 N) and the γ'phase (Fe 4 N) is formed.
　このように実施例１及び実施例２では、高周波誘導加熱又は通電加熱を使用し、試験片１を、アンモニアガス６の雰囲気下で、温度が６００℃～７００℃で、時間が１分～２５分で、加熱する。 As described above, in Examples 1 and 2, high-frequency induction heating or energization heating is used, and the test piece 1 is placed in the atmosphere of ammonia gas 6 at a temperature of 600 ° C. to 700 ° C. and a time of 1 minute to 25. Heat in minutes.
　これにより、いずれの条件においても、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができることが分かる。 As a result, under any of the conditions, the iron nitride compound layer 10 of the ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N), which is excellent in wear resistance, is formed on the surface layer of the test piece 1. It can be seen that it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time treatment suitable for single-piece flow production.
　次に、実施例３に記載する窒化処理装置を説明する。 Next, the nitriding treatment apparatus described in Example 3 will be described.
　図６は、実施例３に記載する窒化処理装置を説明する説明図である。 FIG. 6 is an explanatory diagram illustrating the nitriding treatment apparatus described in the third embodiment.
　実施例３に記載する窒化処理装置は、実施例１に記載する窒化処理装置と比較して、窒化チャンバ２の内部に設置され、窒化チャンバ２に供給されたアンモニアガス６を攪拌する攪拌機１５（強制対流発生部）を有する点が、相違する。 The nitriding apparatus described in Example 3 is installed inside the nitriding chamber 2 and stirs the ammonia gas 6 supplied to the nitriding chamber 2 as compared with the nitriding apparatus described in Example 1. The difference is that it has a forced convection generator).
　実施例３では、攪拌機１５は、窒化チャンバ２の下方に設置されるが、窒化チャンバ２の上方に設置されてもよい。 In the third embodiment, the stirrer 15 is installed below the nitriding chamber 2, but may be installed above the nitriding chamber 2.
　このように、攪拌機１５を使用し、アンモニアガス６の強制対流を発生させることにより、試験片１の表面に未反応のアンモニアガス６を強制的に供給し、更に窒化能力が高い状態で窒化処理することができる。なお、攪拌機１５の攪拌流量は、１００ｍｌ／分とした。 In this way, by using the stirrer 15 to generate forced convection of the ammonia gas 6, the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, and the nitriding treatment is performed in a state where the nitriding ability is further high. can do. The stirring flow rate of the stirrer 15 was 100 ml / min.
　更に、試験片１の表面でアンモニアガス６の強制対流が発生しやすいように、また、アンモニアガス６が均一に試験片１の表面に供給されるように、アンモニアガス６の供給経路に整流板（図示なし）を設置してもよい。これにより、試験片１の表面に未反応のアンモニアガス６が供給され、窒化速度が向上し、更に窒化能力が高い状態で窒化処理することができる。 Further, a straightening vane is provided in the supply path of the ammonia gas 6 so that forced convection of the ammonia gas 6 is likely to occur on the surface of the test piece 1 and the ammonia gas 6 is uniformly supplied to the surface of the test piece 1. (Not shown) may be installed. As a result, the unreacted ammonia gas 6 is supplied to the surface of the test piece 1, the nitriding rate is improved, and the nitriding treatment can be performed in a state where the nitriding ability is further high.
　次に、実施例３にて窒化処理された試験片１の断面組織を説明する。 Next, the cross-sectional structure of the test piece 1 nitrided in Example 3 will be described.
　図７は、実施例３にて窒化処理された試験片１の断面組織を説明する説明図である。 FIG. 7 is an explanatory view illustrating the cross-sectional structure of the test piece 1 nitrided in Example 3.
　図７も、実施例１と同様に、試験片１を輪切りにし、その切り口の外周部の断面組織を、同じ倍率で観察したものである。図７によれば、試験片１の表層部に、厚さ５．０μｍ～６．０μｍ程度（微細なポーラス層を除く）の鉄窒化物の化合物層１０が形成されていることが分かる。 FIG. 7 is also the same as in Example 1, in which the test piece 1 is sliced into round slices, and the cross-sectional structure of the outer peripheral portion of the cut end is observed at the same magnification. According to FIG. 7, it can be seen that the iron nitride compound layer 10 having a thickness of about 5.0 μm to 6.0 μm (excluding the fine porous layer) is formed on the surface layer portion of the test piece 1.
　つまり、厚さ３．０μｍ～４．０μｍ程度の鉄窒化物の化合物層１０であれば、実施例１よりも、短時間で形成することができる。 That is, if the compound layer 10 is an iron nitride having a thickness of about 3.0 μm to 4.0 μm, it can be formed in a shorter time than in Example 1.
　このように、試験片１の表面に未反応のアンモニアガス６を強制的に供給することにより、窒化速度が向上し、更に窒化能力が高い状態で窒化処理することができる。 In this way, by forcibly supplying the unreacted ammonia gas 6 to the surface of the test piece 1, the nitriding rate is improved and the nitriding treatment can be performed in a state where the nitriding ability is further high.
　そして、試験片１の表層部に、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、形成する。 Then, on the surface layer portion of the test piece 1, the iron nitride compound layer 10 of the ε phase (Fe 2-3 N) and the γ'phase (Fe 4 N) having a high nitrogen concentration exceeding 4.5% has a nitrogen content. To form.
　このように実施例３によれば、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間（更に短時間）処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができる。 As described above, according to the third embodiment, the iron nitride compound layer 10 of the ε phase (Fe 2-3 N) and the γ'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for single-piece flow production.
　また、炉加熱のように、アンモニアガス６の全体が加熱される方式Ａにおける窒化速度と、高周波加熱コイル３を使用し、高周波誘導加熱のように、試験片１の近傍で、アンモニアガス６が加熱され、強制対流を発生させた方式Ｃにおける窒化速度と、を比較した。 Further, the nitriding rate in the method A in which the entire ammonia gas 6 is heated like furnace heating and the high frequency heating coil 3 are used, and the ammonia gas 6 is generated in the vicinity of the test piece 1 like high frequency induction heating. The nitriding rate in method C, which was heated and generated forced convection, was compared.
　なお、加熱温度、保持時間、アンモニガス６の濃度を、方式Ａと方式Ｃとで同じとした。 The heating temperature, holding time, and concentration of ammonigas 6 were the same for Method A and Method C.
　比較した結果、試験片１の表層部に、同じ厚さの、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）１１、γ‘相（Ｆｅ４Ｎ）１２の鉄窒化物の化合物層１０が、形成されるのに要する時間は、方式Ａに対して方式Ｃは、約１／５０～１／６０であった。 As a result of comparison, on the surface layer of the test piece 1, the ε phase (Fe 2-3 N) 11 and the γ'phase (Fe 4 N) of the same thickness and high nitrogen concentration exceeding 4.5% were found. The time required for the compound layer 10 of the iron nitride of 12 to be formed was about 1/50 to 1/60 in the method C as opposed to the method A.
　つまり、方式Ｃは、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間（更に短時間）処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができることが分かる。 That is, in the method C, one ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitride compound layers 10 having excellent abrasion resistance are flowed on the surface layer portion of the test piece 1. It can be seen that it can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for production.
　次に、実施例４に記載する窒化処理装置を説明する。 Next, the nitriding treatment apparatus described in Example 4 will be described.
　図８は、実施例４に記載する窒化処理装置を説明する説明図である。 FIG. 8 is an explanatory diagram illustrating the nitriding treatment apparatus described in the fourth embodiment.
　実施例４に記載する窒化処理装置は、実施例３に記載する窒化処理装置と比較して、窒化チャンバ２の内部に設置され、窒化チャンバ２に設置される試験片１を、上下動作させる上下動作部１６（強制対流発生部）を有する点が、相違する。つまり、実施例４は、攪拌機１５の代わりに、上下動作部１６を設置する。 The nitriding apparatus described in Example 4 is installed inside the nitriding chamber 2 and moves the test piece 1 installed in the nitriding chamber 2 up and down as compared with the nitriding apparatus described in Example 3. The difference is that it has an operating unit 16 (forced convection generating unit). That is, in the fourth embodiment, the vertical movement unit 16 is installed instead of the stirrer 15.
　このように、上下動作部１６を使用し、アンモニアガス６の強制対流を発生させることにより、試験片１の表面に未反応のアンモニアガス６を強制的に供給し、更に窒化能力が高い状態で窒化処理することができる。 In this way, by using the vertical movement unit 16 to generate forced convection of the ammonia gas 6, the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, and the nitriding ability is further high. It can be nitrided.
　実施例４によれば、実施例３と比較して、鉄窒化物の化合物層１０の厚さや窒素含有量に多少の差異は認められるものの、試験片１の表層部に、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０が、形成される。 According to Example 4, although there are some differences in the thickness and nitrogen content of the iron nitride compound layer 10 as compared with Example 3, the nitrogen content is 4 in the surface layer portion of the test piece 1. A compound layer 10 of ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitrides having a high nitrogen concentration exceeding 5.5% is formed.
　また、実施例４によれば、試験片１の表層部に、実施例１よりは厚い鉄窒化物の化合物層１０が形成される。つまり、実施例１と同じ厚さの鉄窒化物の化合物層１０であれば、実施例１よりも、短時間で形成することができる。 Further, according to Example 4, a compound layer 10 of iron nitride thicker than that of Example 1 is formed on the surface layer portion of the test piece 1. That is, the iron nitride compound layer 10 having the same thickness as that of Example 1 can be formed in a shorter time than that of Example 1.
　このように実施例４によれば、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間（更に短時間）処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができる。 As described above, according to Example 4, the iron nitride compound layer 10 of the ε phase (Fe 2 to 3 N) and the γ'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for single-piece flow production.
　なお、上下動作部１６は、上下動作と共に回転動作してもよい。 The vertical movement unit 16 may rotate together with the vertical movement.
　次に、実施例５に記載する窒化処理装置を説明する。 Next, the nitriding treatment apparatus described in Example 5 will be described.
　図９は、実施例５に記載する窒化処理装置を説明する説明図である。 FIG. 9 is an explanatory diagram illustrating the nitriding treatment apparatus according to the fifth embodiment.
　実施例５に記載する窒化処理装置は、実施例３に記載する窒化処理装置と比較して、窒化チャンバ２の内部に設置され、窒化チャンバ２に設置される試験片１を、回転動作させる回転動作部１７（強制対流発生部）を有する点が、相違する。つまり、実施例５は、攪拌機１５の代わりに、回転動作部１７を設置する。 The nitriding apparatus described in Example 5 is installed inside the nitriding chamber 2 as compared with the nitriding apparatus described in Example 3, and the test piece 1 installed in the nitriding chamber 2 is rotated. The difference is that it has an operating unit 17 (forced convection generating unit). That is, in the fifth embodiment, the rotary operation unit 17 is installed instead of the stirrer 15.
　このように、回転動作部１７を使用し、アンモニアガス６の強制対流を発生させることにより、試験片１の表面に未反応のアンモニアガス６を強制的に供給し、更に窒化能力が高い状態で窒化処理することができる。 In this way, by using the rotary operation unit 17 to generate forced convection of the ammonia gas 6, the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, and the nitriding ability is further high. It can be nitrided.
　実施例５によれば、実施例３と比較して、鉄窒化物の化合物層１０の厚さや窒素含有量に多少の差異は認められるものの、試験片１の表層部に、窒素含有量が４．５％を超える高窒素濃度のε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０が、形成される。 According to Example 5, although there are some differences in the thickness and nitrogen content of the iron nitride compound layer 10 as compared with Example 3, the nitrogen content is 4 in the surface layer portion of the test piece 1. A compound layer 10 of ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitrides having a high nitrogen concentration exceeding 5.5% is formed.
　また、実施例５によれば、試験片１の表層部に、実施例１よりは厚い鉄窒化物の化合物層１０が形成される。つまり、実施例１と同じ厚さの鉄窒化物の化合物層１０であれば、実施例１よりも、短時間で形成することができる。 Further, according to Example 5, a compound layer 10 of iron nitride thicker than that of Example 1 is formed on the surface layer portion of the test piece 1. That is, the iron nitride compound layer 10 having the same thickness as that of Example 1 can be formed in a shorter time than that of Example 1.
　このように実施例５によれば、試験片１の表層部に、摩損耐久性に優れるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層１０を、１個流し製造に適する短時間（更に短時間）処理で、高い熱効率で、窒化ガスの使用量を低減し、低環境負荷で、形成することができる。 As described above, according to Example 5, the iron nitride compound layer 10 of the ε phase (Fe 2 to 3 N) and the γ'phase (Fe 4 N) having excellent wear resistance is formed on the surface layer portion of the test piece 1. It can be formed with high thermal efficiency, reduced amount of nitride gas used, and low environmental load by a short-time (further short-time) treatment suitable for single-piece flow production.
　なお、回転動作部１７は、回転動作と共に上下動作してもよい。 The rotation operation unit 17 may move up and down together with the rotation operation.
　また、回転動作部１７に、羽（図示せず）を設置してもよい。これにより、試験片１の表面に未反応のアンモニアガス６が強制的に供給され、窒化速度が向上し、更に窒化能力が高い状態で窒化処理することができる。 Further, wings (not shown) may be installed on the rotary motion unit 17. As a result, the unreacted ammonia gas 6 is forcibly supplied to the surface of the test piece 1, the nitriding rate is improved, and the nitriding treatment can be performed in a state where the nitriding ability is further high.
　なお、本発明は上記した実施例に限定されるものではなく、様々な変形例が含まれる。
例えば、上記した実施例は本発明を分かりやすく説明するために、具体的に説明したものであり、必ずしも説明した全ての構成を有するものに限定されるものではない。 The present invention is not limited to the above-described examples, and includes various modifications.
For example, the above-described embodiment has been specifically described in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations.
　また、ある実施例の構成の一部を、他の実施例の構成の一部に置換することもできる。
また、ある実施例の構成に他の実施例の構成を追加することもできる。また、各実施例の構成の一部について、それを削除し、他の構成の一部を追加し、他の構成の一部と置換することもできる。 It is also possible to replace a part of the configuration of one embodiment with a part of the configuration of another embodiment.
It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete a part of the configuration of each embodiment, add a part of the other configuration, and replace it with a part of the other configuration.
　１…試験片、２…窒化チャンバ、３…高周波加熱コイル、４…真空ポンプ、５…アンモニアガスボンベ、６…アンモニアガス、７…高周波電源、８…窒素ガスボンベ、９…窒素ガス、１０…鉄窒化物の化合物層、１１…ε相（Ｆｅ２～３Ｎ）、１２…γ‘相（Ｆｅ４Ｎ）、１３…拡散層、１４…α相、１５…攪拌機、１６…上下動作部、１７…回転動作部。 1 ... Test piece, 2 ... Nitride chamber, 3 ... High frequency heating coil, 4 ... Vacuum pump, 5 ... Ammonia gas cylinder, 6 ... Ammonia gas, 7 ... High frequency power supply, 8 ... Nitrogen gas cylinder, 9 ... Nitrogen gas, 10 ... Iron nitride Compound layer of material, 11 ... ε phase (Fe 2-3 N), 12 ... γ'phase (Fe 4 N), 13 ... diffusion layer, 14 ... α phase, 15 ... stirrer, 16 ... vertical movement part, 17 ... Rotating part.

Claims (7)

  1. 　高周波誘導加熱又は通電加熱を使用し、温度が６００℃～７００℃で、時間が１分～２５分で、窒化ガスの雰囲気下で、鉄鋼材からなる摺動部材を加熱し、前記摺動部材の表層部に、窒素含有量が４．５％を超えるε相（Ｆｅ２～３Ｎ）、γ‘相（Ｆｅ４Ｎ）の鉄窒化物の化合物層を形成することを特徴とする窒化処理方法。 Using high-frequency induction heating or energization heating, a sliding member made of steel is heated at a temperature of 600 ° C. to 700 ° C., a time of 1 minute to 25 minutes, and an atmosphere of nitriding gas, and the sliding member is described. Nitriding treatment characterized by forming a compound layer of ε-phase (Fe 2-3 N) and γ'phase (Fe 4 N) iron nitride having a nitrogen content of more than 4.5% on the surface layer portion of the above. Method.
  2. 　請求項１に記載する窒化処理方法であって、
    　前記摺動部材を加熱した後、前記摺動部材を冷却することを特徴とする窒化処理方法。     The nitriding treatment method according to claim 1.
    A nitriding treatment method comprising heating the sliding member and then cooling the sliding member.
  3. 　請求項１に記載する窒化処理方法であって、
    　前記摺動部材の表面に、前記窒化ガスを自然対流又は強制対流により供給することを特徴とする窒化処理方法。     The nitriding treatment method according to claim 1.
    A nitriding treatment method comprising supplying the nitriding gas to the surface of the sliding member by natural convection or forced convection.
  4. 　鉄鋼材からなる摺動部材を設置する窒化チャンバと、前記窒化チャンバに設置され、前記摺動部材を高周波加熱する高周波加熱コイルと、前記窒化チャンバを真空排気する真空ポンプと、前記窒化チャンバに、窒化ガスを供給する窒化ガスボンベと、前記窒化チャンバに、窒素ガスを供給する窒素ガスボンベと、前記高周波加熱コイルに接続され、前記高周波加熱コイルに通電する高周波電源と、前記窒化チャンバに設置され、前記窒化ガスに強制対流を発生させる強制対流発生部と、を有することを特徴とする窒化処理装置。 A nitriding chamber in which a sliding member made of steel is installed, a high-frequency heating coil installed in the nitriding chamber for high-frequency heating of the sliding member, a vacuum pump for vacuum exhausting the nitriding chamber, and the nitriding chamber. A nitriding gas cylinder that supplies nitriding gas, a nitrogen gas cylinder that supplies nitrogen gas to the nitriding chamber, a high-frequency power supply that is connected to the high-frequency heating coil and energizes the high-frequency heating coil, and a nitriding chamber that is installed in the nitriding chamber. A nitriding processing apparatus comprising: a forced convection generating portion for generating forced convection in a nitriding gas.
  5. 　請求項４に記載する窒化処理装置であって、
    　強制対流発生部が、前記窒化ガスを攪拌する攪拌機であることを特徴とする窒化処理装置。     The nitriding apparatus according to claim 4.
    A nitriding treatment apparatus characterized in that the forced convection generating portion is a stirrer for stirring the nitriding gas.
  6. 　請求項４に記載する窒化処理装置であって、
    　強制対流発生部が、前記摺動部材を、上下動作させる上下動作部であることを特徴とする窒化処理装置。     The nitriding apparatus according to claim 4.
    A nitriding processing apparatus characterized in that the forced convection generating portion is a vertical moving portion that moves the sliding member up and down.
  7. 　請求項４に記載する窒化処理装置であって、
    　強制対流発生部が、前記摺動部材を、回転動作させる回転動作部であることを特徴とする窒化処理装置。     The nitriding apparatus according to claim 4.
    A nitriding processing apparatus characterized in that the forced convection generating portion is a rotating operating portion that rotates the sliding member.
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