EP1707646A1 - Verfahren zur aktivierung der oberfläche eines metallbauelements - Google Patents

Verfahren zur aktivierung der oberfläche eines metallbauelements Download PDF

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EP1707646A1
EP1707646A1 EP05703844A EP05703844A EP1707646A1 EP 1707646 A1 EP1707646 A1 EP 1707646A1 EP 05703844 A EP05703844 A EP 05703844A EP 05703844 A EP05703844 A EP 05703844A EP 1707646 A1 EP1707646 A1 EP 1707646A1
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gas
furnace
hcn
treatment
metal
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French (fr)
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EP1707646A4 (de
EP1707646B1 (de
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Kaoru PARKER NETSUSHORI KOGYO K.K. HOSHINO
Makoto PARKER NETSUSHORI KOGYO K.K MIYASHITA
Takashi PARKER NETSUSHORI KOGYO K.K KAWAMURA
Toshiko PARKER NETSUSHORI KOGYO K.K. TOTSUKA
Hiroshi PARKER NETSUSHORI KOGYO K.K. EIRAKU
Kuniji PARKER NETSUSHORI KOGYO K.K. YASHIRO
Takumi PARKER NETSUSHORI KOGYO K.K. KUROSAWA
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Parker Netsushori Kogyo KK
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Parker Netsushori Kogyo KK
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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
    • C23C8/02—Pretreatment of the material to be coated
    • 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
    • C23C8/28—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 more than one element being applied in one step
    • C23C8/30—Carbo-nitriding
    • 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
    • C23C8/28—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 more than one element being applied in one step
    • C23C8/30—Carbo-nitriding
    • C23C8/32—Carbo-nitriding of ferrous surfaces

Definitions

  • the invention of the present application relates to a method for the pretreatment of a metal member to activate a surface of the metal member before applying diffusion treatment such as nitriding or carburizing to the metal member.
  • gas nitriding or gas carburizing that forms a nitrided layer or carburized layer in a surface of a metal member is widely applied primarily to members made of iron-based material.
  • Such a chloride is placed together with a metal member in a treatment furnace and is heated there. By this heating, the chloride is decomposed to form HCl, and the thus-formed HCl decomposes a passivated film on a surface of the metal member to activate the surface so that diffusion treatment such as nitriding or carburizing as a next step is assured.
  • a metal member by such a chloride results in the erosion of a furnace wall made of bricks or a metal by HCl formed through decomposition, and in gas nitriding or gas softnitriding, HCl so formed reacts with ammonia as atmosphere gas to form ammonium chloride, which not only deposits in the furnace or an exhaust system to cause troubles but also remains on the surface of the metal member (work) to induce reductions in the corrosion resistance and fatigue strength of the member.
  • an activation method of the surface of a metal member with a compound of fluorine which belongs to the same halogen group, NF 3 has been put into practical use in recent years (for example, Patent Document 1).
  • NF 3 is decomposed to form fluorine, and the thus-formed fluorine converts a passivated film on the surface of the metal member into a fluoride film to activate the surface of the metal member.
  • the activation method of the surface of the metal member with the fluorine compound (NF 3 ) requires sophisticated treatment for the detoxification of NF 3 and HF contained in effluent gas, which prevents the wide-spread adoption of the method.
  • the ammonia gas nitriding method disclosed in Patent Document 2 reductively activates a passivated film on a surface of a high-chromium alloy steel member by forming reducing radicals and CO at the surface of the alloy steel member through the pyrolysis of acetone.
  • acetone is pyrolyzed on the heated surface of the high-chromium alloy steel member in accordance with the below-described formula (1) so that reducing radicals and CO are formed at the surface of the high-chromium alloy steel member.
  • the above-described chloride-dependent activation method of a surface of a high-chromium alloy steel member can be expressed by the following formula (6) : Cr 2 O 3 + 6HCl ⁇ 2CrCl 3 + 3H 2 O (6)
  • the chromium chloride remains on the surface of the member, and acts as a causative substance for the corrosion of the member.
  • Patent Document 2 is good in that it has theoretically solved the problems of the chloride-dependent activation method for a surface of a metal member as disclosed in Patent Document 1. Nonetheless, the method disclosed in Patent Document 2 is accompanied by a drawback that the use of acetone, which is liquid at normal temperature and pressure, requires facilities for the introduction of acetone vapor and the difficult flow rate control of acetone makes it hard to obtain a metal member having an evenly-activated surface.
  • the present inventors have struggled to develop a method that makes use of a compound, which is gaseous at normal temperature and pressure, in place of acetone involving the problems in handling, leading to the completion of the present invention. Described specifically, the present invention provides:
  • carbon donor compound is at least one compound selected from acetylene, ethylene, propane, butane and carbon monoxide.
  • metal-made inner wall of the heating furnace or the metal-made jig contains at least one metal selected from Fe, Ni, Co, Cu, Cr, Mo, Nb, V, Ti and Zr.
  • a passivated film on a surface of a high-alloy steel member makes it difficult to apply diffusion treatment, such as gas nitriding or gas carburizing, that forms a nitrided layer, carburized layer or carbonitrided layer on the surface of the steel member.
  • diffusion treatment such as gas nitriding or gas carburizing
  • an activating treatment method is provided for the surface of the metal member. This method is not accompanied by problems of conventional activation treatment with a halide, such as furnace deposits, furnace wall erosion and effluent gas detoxification treatment, and is useful as pretreatment for diffusion treatment.
  • the passivated surface of the high-alloy steel member can be activated by using a gas commonly employed in gas heat treatment, and forming HCN gas in a heating furnace while making use of catalytic action of the steel member or a surface of the furnace.
  • HCN-forming reactions between ammonia and the above-mentioned carbon-containing compounds can be expressed by the following formulas, respectively: NH 3 + CO ⁇ HCN + H 2 O (7) 2NH 3 + 2CO 2 ⁇ 2HCN + H 2 O + O 2 (8) 2NH 3 + C 2 H 2 ⁇ 2HCN + 3H 2 (9) 2NH 3 + C 2 H 4 ⁇ 2HCN + 4H 2 (10) 3NH 3 + C 3 H 8 ⁇ 3HCN + 7H 2 (11) 4NH 3 + C 4 H 10 ⁇ 4HCN + 9H 2 (12)
  • RX gas means a gas, which is formed by mixing substantially equal chemical equivalents of a hydrocarbon gas (for example, propane gas, butane gas, or natural gas) and air and causing them to decompose in a catalyst layer maintained at 1,000°C, contains CO and H 2 (N 2 ) as a primary component and small amounts of CO 2 and H 2 O, and is widely used as a nitriding gas.
  • a hydrocarbon gas for example, propane gas, butane gas, or natural gas
  • the CO contained in NH 3 :RX gas 1:1 by molar ratio, a typical composition for gas softnitriding, amounts to about 10% in terms of volume percentage.
  • HCN which is required for the activation of a surface of a metal member, is therefore presumed to exist sufficiently in a gas softnitriding furnace.
  • RX gas the dew point of which is not controlled, however, there are a significant amount of H 2 O (around 2 vol.%) and about 0.5 vol.% of CO 2 . It is, therefore, judged that by their oxidizing action, the activated surface of the SUS304 plate is re-oxidized to prevent the penetration of nitrogen into the surface of the plate.
  • CO gas When CO gas is selected as a carbon donor compound for the activation of a surface of a metal member, it is thus desired to use CO gas singly instead of RX gas. Because the amount of CO gas required to be injected in the present invention is as little as 1/10 (by volume) or so of a gas softnitriding atmosphere, the effects of H 2 O and CO 2 in RX gas are reduced so that RX gas may be used as a CO source in some instances.
  • the activating effect for the surface of the alloy steel member in the present invention is attributed to HCN.
  • the above-described activating effect is dependent on the concentration of HCN in the furnace atmosphere.
  • the concentration of HCN can appropriately be in a range of from 100 to 30, 000 mg/m 3 .
  • the above-described activating effect cannot be expected.
  • the above-described activating effect is saturated, resulting not only in an economical disadvantage but also in the occurrence of sooting (the formation of carbon in the furnace) by pyrolysis of the carbon donor compound. Therefore, HCN concentrations outside the above-described range are not preferred.
  • the dew point of the furnace atmosphere gas may preferably be 5°C or lower. If the dew point is higher than 5°C, the metal surface activated by HCN gas is re-oxidized with H 2 O in the atmosphere and accordingly, is passivated back again.
  • the method according to the present invention is also advantageous from the environmental standpoint in that as explained in the reaction formula (5), the HCN attributed to the activation of the surface of the metal member is absorbed into the member and attributes to the nitriding and carburizing of the member to leave no residue on the surface of the member and the HCN discharged as effluent gas without any contribution to the reaction can be readily burned and detoxified in an ammonia combustion facility arranged as an attachment for the nitriding facility to obviate any new additional facility.
  • a further advantage of the present invention is that the time of nitriding treatment can be shortened owing to the smooth progress of the steps in the nitriding treatment process.
  • Gas nitriding of a metal member is generally conducted in such a schedule as will be described below.
  • the metal member is set in a furnace, and subsequent to vacuum purging or nitrogen gas replacement of the air in the furnace, the temperature is raised to a nitriding temperature of the metal member and is then maintained constantly at the temperature, both while introducing the nitriding atmosphere gas (NH 3 + N 2 ) at a rate as much as 1 to 10 times the internal volume of the furnace per hour.
  • the internal pressure of the furnace is maintained at atmospheric pressure + 0.5 kPa or so by a pressure control valve, and the force-out effluent gas is caused to burn and decompose in an effluent gas combustion facility.
  • Patent Document 1 According to the method disclosed in Patent Document 1 and making use of the fluorine-based gas, it is necessary, subsequent to the introduction of the fluorine-based gas and the activation treatment of the member, to exhaust the fluorine-based gas and then to introduce the nitriding atmosphere gas into the furnace as disclosed in the examples of the specification of Japanese Patent No. 2,501,925 .
  • the carbon donor compound is introduced into the nitriding atmosphere gas during the step in which the metal member is heated to the nitriding treatment temperature.
  • HCN is formed to activate the surface of the metal member, and the subsequent termination of the introduction of the carbon donor compound makes it possible to advance directly to the nitriding step.
  • the treatment time of the nitriding step is substantially shortened, thereby making it possible to fundamentally eliminate the re-oxidation phenomenon of the surface of the metal member which has until now remained as a problem in the conventional treatment upon advancing from the activation step to the nitriding step.
  • the inner wall can preferably be made of metal. Even if the inner wall is not made of metal, the present invention can still be practiced provided that the metal member to be treated acts as a catalyst for the formation of HCN or a jig adapted to hold the metal member within the furnace is made of metal.
  • the metal that makes up the metal-made inner wall, metal member or jig may preferably contain, for example, one or more metals selected from Fe, Ni, Co, Cu, Cr, Mo, Nb, V, Ti and Zr.
  • these metal members are held by suitable jigs and are subjected to surface activation treatment in a manner known per se in the art.
  • the surface treatment gases to be fed into the furnace are the carbon donor compound, which is gaseous at normal temperature and pressure, and ammonia, which are fed from their own gas cylinders into the furnace.
  • the nitriding atmosphere gas (ammonia alone, ammonia + nitrogen gas, or ammonia + nitrogen gas + hydrogen gas) is introduced into the furnace to establish a reducing atmosphere.
  • heating is initiated, followed by the introduction of the carbon donor compound useful in the present invention.
  • the ammonia gas and carbon donor compound form HCN under the catalytic action of the metal surface when they are heated to 300°C or higher in the furnace.
  • the ratio of the flow rate of ammonia as a nitriding atmosphere gas to that of the introduced carbon donor compound should be controlled within a range of from 1:0.0001 to 1:0.1. If the flow rate of the carbon donor compound is so low that the flow rate ratio becomes smaller than 1:0.0001, HCN is formed too little to bring about its activating effect. If the flow rate of the carbon donor compound is so high that the flow rate ratio becomes greater than 1:0.1, on the other hand, the activating effect is saturated to result in an economical disadvantage.
  • the carbon donor compound is composed of one or more gaseous compounds selected from acetylene, ethylene, propane, butane and carbon monoxide as described above, and can be fed into the treatment furnace concurrently with the ammonia-containing gas as mentioned above. It is preferred for the efficient utilization of the carbon donor compound to initiate the introduction of the carbon donor compound at the time point that the temperature of the ammonia-containing gas within the furnace has reached about 300°C. To raise the concentration of the carbon donor compound in the furnace atmosphere at such an early stage as permitting shortening the treatment time, however, it is desired to introduce the carbon donor compound at the same time as the initiation of heating and to assure the formation of HCN from the initial stage.
  • FIG. 1 shows a Muffle furnace 1, an outer shell 2 of the Muffle furnace, a heater 3, an internal container (retort) 4, a gas inlet pipe 5, an exhaust pipe 6, a motor 7, a fan 8, a metal-made jig 9, a gas guide cylinder 10, an inverted funnel 11, a vacuum pump 12, an effluent gas combustion facility 13, a carbon donor compound gas cylinder 14, an ammonia gas cylinder 15, a nitrogen gas cylinder 16, a hydrogen gas cylinder 17, a flowratemeter 18, and a gas control valve 19.
  • Effluent gas from the furnace was branched off to have a portion of the effluent gas absorbed in a 2 wt.% aqueous solution of caustic soda, and an analysis was performed for HCN. From the analysis results of the HCN-absorbed solution, the average HCN concentration in the furnace atmosphere during the acetylene gas injection period was 8,000 mg/m 3 . Some of the SUS304 specimens were weighed to determine a weight increase after the nitriding treatment. As a result, the weight increase was determined to be 20 g/m 2 . Some of the SUS304 specimens were cut, and their cut surfaces were polished, etched with Marble's solution, and then observed under an optical microscope.
  • Nitrided layers of 50- ⁇ m uniform thickness were found to be formed (a 500x micrograph is shown in FIG. 2). Some of the remaining specimens were measured for surface hardness at 5 points by a Vickers hardness tester. All the values (Hv) distributed between 1,200 and 1,250.
  • SUS304 plates were set in the Muffle furnace employed in Example 1, NH 3 gas and N 2 gas were fed at flow rates of 200 L/H, respectively, and the furnace atmosphere was heated from room temperature to 550°C in 75 minutes. At the time point that the atmosphere temperature had reached 100°C in the course of the heating (at the 18 th minute after the initiation of the heating), an injection of propane gas was initiated at 5 L/hr. After heated to 550°C, the atmosphere temperature was maintained for 2 hours. At that time point, the injection of propane gas was terminated and instead, NH 3 gas and N 2 gas were then fed at 550°C for 4 hours to allow nitriding to proceed. Subsequently, the heating was stopped and N 2 gas alone was continuously fed to cool down the furnace. When the atmosphere temperature had dropped to 100°C or lower, the specimens were taken out of the furnace.
  • Effluent gas from the furnace was branched off to have a portion of the effluent gas absorbed in a 2 wt.% aqueous solution of caustic soda, and an analysis was performed for HCN. From the analysis results of the HCN-absorbed solution, the average HCN concentration in the furnace atmosphere during the propane gas injection period was 400 mg/m 3 .
  • Some of the SUS304 specimens were weighed to determine a weight increase after the nitriding treatment. As a result, the weight increase was determined to be 18 g/m 2 .
  • Some of the SUS304 specimens were cut, and their cut surfaces were polished, etched with Marble's solution, and then observed under an optical microscope. Nitrided layers of 45- ⁇ m uniform thickness were found to be formed. Some of the remaining specimens were measured for surface hardness at 5 points by a Vickers hardness tester. All the values (Hv) distributed between 1,200 and 1,250.
  • SUS304 plates were set in the Muffle furnace employed in Example 1, NH 3 gas and N 2 gas were fed at flow rates of 200 L/H, respectively, and the furnace atmosphere was heated from room temperature to 550°C in 75 minutes. At the time point that the atmosphere temperature had reached 100°C in the course of the heating (at the 18 th minute after the initiation of the heating), an injection of CO gas was initiated at 5 L/hr. After heated to 550°C, the atmosphere temperature was maintained for 2 hours. At that time point, the injection of CO gas was terminated and instead, NH 3 gas and N 2 gas were then fed for 4 hours to allow nitriding to proceed. Subsequently, the heating was stopped and N 2 gas alone was continuously fed at 550°C to cool down the furnace. When the atmosphere temperature had dropped to 100°C or lower, the specimens were taken out of the furnace.
  • Effluent gas from the furnace was branched off to have a portion of the effluent gas absorbed in a 2 wt.% aqueous solution of caustic soda, and an analysis was performed for HCN. From the analysis results of the HCN-absorbed solution, the average HCN concentration in the furnace atmosphere during the CO gas injection period was 1,000 mg/m 3 .
  • Some of the SUS304 specimens were weighed to determine a weight increase after the nitriding treatment. As a result, the weight increase was determined to be 18 g/m 2 .
  • Some of the SUS304 specimens were cut, and their cut surfaces were polished, etched with Marble's solution, and then observed under an optical microscope. Nitrided layers of 45- ⁇ m uniform thickness were found to be formed. Some of the remaining specimens were measured for surface hardness at 5 points by a Vickers hardness tester. All the values (Hv) distributed between 1,200 and 1,250.
  • SUS304 plates were set in the Muffle furnace employed in Example 1, NH 3 gas and N 2 gas were fed at flow rates of 200 L/H, respectively, and the furnace atmosphere was heated from room temperature to 550°C in 75 minutes. At the time point that the atmosphere temperature had reached 100°C in the course of the heating (at the 18 th minute after the initiation of the heating), an injection of C 2 H 4 gas was initiated at 5 L/hr. After heated to 550°C, the atmosphere temperature was maintained for 2 hours. At that time point, the injection of C 2 H 4 gas was terminated and instead, NH 3 gas and N 2 gas were then fed at 550°C for 4 hours to allow nitriding to proceed. Subsequently, the heating was stopped and N 2 gas alone was continuously fed to cool down the furnace. When the atmosphere temperature had dropped to 100°C or lower, the specimens were taken out of the furnace.
  • Effluent gas from the furnace was branched off to have a portion of the effluent gas absorbed in a 2 wt.% aqueous solution of caustic soda, and an analysis was performed for HCN. From the analysis results of the HCN-absorbed solution, the average HCN concentration in the furnace atmosphere during the C 2 H 4 gas injection period was 1,200 mg/m 3 .
  • Some of the SUS304 specimens were weighed to determine a weight increase after the nitriding treatment. As a result, the weight increase was determined to be 18 g/m 2 .
  • Some of the SUS304 specimens were cut, and their cut surfaces were polished, etched with Marble's solution, and then observed under an optical microscope. Nitrided layers of 45- ⁇ m uniform thickness were found to be formed. Some of the remaining specimens were measured for surface hardness at 5 points by a Vickers hardness tester. All the values (Hv) distributed between 1,200 and 1,250.
  • SUS304 plates were set in the Muffle furnace employed in Example 1, NH 3 gas and N 2 gas were fed at flow rates of 200 L/H, respectively, and the furnace atmosphere was heated from room temperature to 550°C in 75 minutes. At the time point that the atmosphere temperature had reached 100°C in the course of the heating (at the 18 th minute after the initiation of the heating), an injection of C 4 H 10 gas was initiated at 5 L/hr. After heated to 550°C, the atmosphere temperature was maintained for 2 hours. At that time point, the injection of C 4 H 10 gas was terminated and instead, NH 3 gas and N 2 gas were then fed at 550°C for 4 hours to allow nitriding to proceed. Subsequently, the heating was stopped and N 2 gas alone was continuously fed to cool down the furnace. When the atmosphere temperature had dropped to 100°C or lower, the specimens were taken out of the furnace.
  • Effluent gas from the furnace was branched off to have a portion of the effluent gas absorbed in a 2 wt.% aqueous solution of caustic soda, and an analysis was performed for HCN. From the analysis results of the HCN-absorbed solution, the average HCN concentration in the furnace atmosphere during the C 4 H 10 gas injection period was 600 mg/m 3 .
  • Some of the SUS304 specimens were weighed to determine a weight increase after the nitriding treatment. As a result, the weight increase was determined to be 18 g/m 2 .
  • Some of the SUS304 specimens were cut, and their cut surfaces were polished, etched with Marble' s solution, and then observed under an optical microscope. Nitrided layers of 45- ⁇ m uniform thickness were found to be formed. Some of the remaining specimens were measured for surface hardness at 5 points by a Vickers hardness tester. All the values (Hv) distributed between 1,200 and 1,250.
  • SUS304 plates were set in the Muffle furnace employed in Example 1, NH 3 gas and N 2 gas were fed at flow rates of 200 L/H, respectively, and the furnace atmosphere was heated from room temperature to 550°C in 75 minutes. After heated to 550°C, the atmosphere temperature was maintained for 6 hours. NH 3 gas and N 2 gas were continuously fed to allow nitriding to proceed. Subsequently, the heating was stopped and N 2 gas alone was continuously fed to cool down the furnace. When the atmosphere temperature had dropped to 100°C or lower, the specimens were taken out of the furnace.
  • Effluent gas from the furnace was branched off to have a portion of the effluent gas absorbed in a 2 wt.% aqueous solution of caustic soda, and an analysis was performed for HCN. From the analysis results of the HCN-absorbed solution, HCN was not detected at all, thereby ascertaining that HCN did not exist at all in the furnace atmosphere.
  • Some of the SUS304 specimens were weighed to determine a weight increase after the nitriding treatment. As a result, the weight increase was determined to be 10 g/m 2 .
  • Some of the SUS304 specimens were cut, and their cut surfaces were polished, etched with Marble's solution, and then observed under an optical microscope.
  • Nitrided layers of uneven thicknesses of from 8 to 18 ⁇ m were found to be formed (a 500x micrograph is shown in FIG. 3). Some of the remaining specimens were measured for surface hardness at 5 points by a Vickers hardness tester. The values (Hv) considerably varied from 500 to 1,100, and their absolute values were found to be lower compared with the corresponding values of the examples.
  • a passivated film on a surface of a high-alloy steel member makes it difficult to apply diffusion treatment, such as gas nitriding or gas carburizing, that forms a nitrided layer, carburized layer or carbonitrided layer on the surface of the steel member.
  • diffusion treatment such as gas nitriding or gas carburizing
  • an activating treatment method is provided for the surface of the metal member. This method is not accompanied by problems of conventional activation treatment with a halide, such as furnace deposits, furnace wall erosion and effluent gas detoxification treatment, and is useful as pretreatment for diffusion treatment.
  • the passivated surface of the high-alloy steel member can be activated by using a gas commonly employed in gas heat treatment, and forming HCN gas in a heating furnace while making use of catalytic action of the steel member or a surface of the furnace.
  • FIG. 1 A diagram illustrating the construction of a treatment furnace useful in the present invention.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
EP05703844A 2004-01-20 2005-01-19 Verfahren zur aktivierung der oberfläche eines metallbauelements Expired - Fee Related EP1707646B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2004012328 2004-01-20
PCT/JP2005/000607 WO2005068679A1 (ja) 2004-01-20 2005-01-19 金属部材表面の活性化方法

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EP1707646A1 true EP1707646A1 (de) 2006-10-04
EP1707646A4 EP1707646A4 (de) 2008-09-03
EP1707646B1 EP1707646B1 (de) 2009-08-12

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US (1) US20070204934A1 (de)
EP (1) EP1707646B1 (de)
JP (1) JP4861703B2 (de)
KR (1) KR100858598B1 (de)
CN (1) CN1910303B (de)
DE (1) DE602005015934D1 (de)
WO (1) WO2005068679A1 (de)

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EP2278038A1 (de) * 2009-07-20 2011-01-26 Danmarks Tekniske Universitet (DTU) Verfahren zur Aktivierung eines Artikels eines passiven eisenhaltigen oder nichteisenhaltigen Metalls vor dem Aufkohlen, Nitrieren und/oder Nitroaufkohlen

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006233261A (ja) * 2005-02-24 2006-09-07 Nippon Techno:Kk ガス窒化処理方法
KR100902169B1 (ko) * 2007-07-24 2009-06-10 쳉-시엔 리우 마르텐사이트계 스테인레스 표면경도 강화방법
CN102844459B (zh) 2009-08-07 2016-03-30 世伟洛克公司 低真空下的低温渗碳
US8961711B2 (en) 2010-05-24 2015-02-24 Air Products And Chemicals, Inc. Method and apparatus for nitriding metal articles
CN102168269A (zh) * 2011-03-16 2011-08-31 广州有色金属研究院 一种催渗等离子氮碳共渗与氮碳化钛复合膜层的制备方法
KR101245564B1 (ko) * 2011-05-06 2013-03-20 주식회사 삼락열처리 스테인레스강, 내열강 및 고합금강에 대한 가스질화방법
AU2013210034A1 (en) 2012-01-20 2014-09-11 Swagelok Company Concurrent flow of activating gas in low temperature carburization
TWI548778B (zh) * 2014-02-11 2016-09-11 國立臺灣大學 不銹鋼表面處理方法及不銹鋼處理系統
JP6357042B2 (ja) * 2014-07-18 2018-07-11 株式会社日本テクノ ガス軟窒化方法およびガス軟窒化装置
JP6516238B2 (ja) * 2015-03-30 2019-05-22 日鉄ステンレス株式会社 オーステナイト系ステンレス鋼及びその製造法
TWI798885B (zh) 2020-11-18 2023-04-11 日商帕卡熱處理工業股份有限公司 金屬構件之處理方法及處理裝置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE851810C (de) * 1943-06-19 1952-10-09 Bergwerksverband Zur Verwertun Zementieren von Gegenstaenden aus Eisen, Stahl und deren Legierungen
GB1293053A (en) * 1969-06-25 1972-10-18 Uss Eng & Consult Method and apparatus for maintaining the composition of a nitriding atmosphere

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1984411A (en) * 1933-06-08 1934-12-18 Du Pont Method of case hardening
US2095565A (en) * 1936-11-18 1937-10-12 Electro Alloys Company Carburizing box
US2404060A (en) * 1944-02-03 1946-07-16 Westinghouse Electric Corp High temperature furnace
US3281517A (en) * 1963-11-19 1966-10-25 Melpar Inc Vacuum furnace
JPS51105938A (en) * 1975-02-28 1976-09-20 Fujikoshi Kk Ko chutetsuno teionshintanchitsukashorihoho
JPS52145344A (en) * 1976-05-31 1977-12-03 Daido Steel Co Ltd Method of preparing atmosphere gas for soft nitriding
US4145232A (en) * 1977-06-03 1979-03-20 Union Carbide Corporation Process for carburizing steel
US4175986A (en) * 1978-10-19 1979-11-27 Trw Inc. Inert carrier gas heat treating control process
US4406714A (en) * 1980-05-02 1983-09-27 Bowes Robert G Heat treatment of metals
JPH05202464A (ja) * 1992-01-27 1993-08-10 Parker Netsushiyori Kogyo Kk 部品の部分窒化方法
CA2215897C (en) * 1995-03-29 2001-01-16 Jh Corporation Vacuum carburizing method and device, and carburized products
JPH10219418A (ja) * 1997-02-06 1998-08-18 Nippon Bell Parts Kk 高クロム合金鋼のアンモニアガス窒化方法
JP3960697B2 (ja) * 1998-12-10 2007-08-15 株式会社日本テクノ 浸炭および浸炭窒化処理方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE851810C (de) * 1943-06-19 1952-10-09 Bergwerksverband Zur Verwertun Zementieren von Gegenstaenden aus Eisen, Stahl und deren Legierungen
GB1293053A (en) * 1969-06-25 1972-10-18 Uss Eng & Consult Method and apparatus for maintaining the composition of a nitriding atmosphere

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2005068679A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2278038A1 (de) * 2009-07-20 2011-01-26 Danmarks Tekniske Universitet (DTU) Verfahren zur Aktivierung eines Artikels eines passiven eisenhaltigen oder nichteisenhaltigen Metalls vor dem Aufkohlen, Nitrieren und/oder Nitroaufkohlen
US8845823B2 (en) 2009-07-20 2014-09-30 Expanite A/S Method of activating an article of passive ferrous or non-ferrous metal prior to carburising, nitriding and /or nitrocarburising

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US20070204934A1 (en) 2007-09-06
CN1910303B (zh) 2010-05-12
EP1707646A4 (de) 2008-09-03
EP1707646B1 (de) 2009-08-12
KR100858598B1 (ko) 2008-09-17
WO2005068679A1 (ja) 2005-07-28
DE602005015934D1 (de) 2009-09-24
JP4861703B2 (ja) 2012-01-25
CN1910303A (zh) 2007-02-07
JPWO2005068679A1 (ja) 2007-12-27

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