JP2004346427A - Method and apparatus for surface-treating metallic workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heretofore not attainably effective epochmaking method for surface-treating a metallic workpiece and to provide a surface treatment apparatus therefor. <P>SOLUTION: The method comprises setting the metallic workpiece in a treatment space 1, evacuating the space 1, and feeding high-pressure superheated steam into the space 1 to form an oxide film on the surface of the metallic workpiece. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a metal workpiece surface treatment method and a metal workpiece surface treatment apparatus.

  2. Description of the Related Art Conventionally, a surface treatment method for forming an oxide film on a surface of a metal work constituting a metal product such as a cutting tool or a mold (commonly called Homo (homo) treatment) has been proposed (hereinafter, referred to as a conventional method). .

In this conventional method, first, a metal work is disposed in a processing space of a heating furnace and heated to about 400 ° C. (this causes water droplets to condense on the surface of the metal work by blowing steam in the next step, and red rust occurs. Can be prevented.) Then, by blowing steam into the processing space that has reached approximately 400 ° C., the air in the processing space is expelled to the outside in about 30 minutes, and then the metal work is processed. This is a method of forming an oxide film (Fe ₃ O ₄ ) on the surface of a metal work by heating at a temperature (about 500 ° C.) for about 2 hours and continuously introducing steam into the processing space.

  Since the oxide film formed on the surface of the metal work by this conventional method is porous, the oxide film has excellent smoothness and oil holding power, and thus extends the life of the metal product.

  The present applicant has further researched and developed the conventional method, and has invented a revolutionary metal work surface treatment method and a metal work surface treatment apparatus that exhibit an operation and effect not found in the conventional method.

  The gist of the present invention will be described with reference to the accompanying drawings.

  A metal work is provided in the processing space 1, and after the processing space 1 is evacuated, high-pressure superheated steam is introduced into the processing space 1 to form an oxide film on the surface of the metal work. The present invention relates to a surface treatment method for a work.

  Further, a metal work is disposed in the processing space 1, subsequently, an appropriate gas is introduced into the processing space 1, and subsequently, high-pressure superheated steam is introduced into the processing space 1 to form an oxide film on the surface of the metal work. The present invention relates to a method for treating a surface of a metal workpiece, which is characterized by being formed.

  Further, a metal work is disposed in the processing space 1, and after the processing space 1 is evacuated, an appropriate gas is introduced into the processing space 1, and subsequently, high-pressure superheated steam is introduced into the processing space 1, and The present invention relates to a method for treating a surface of a metal work, wherein an oxide film is formed on the surface of the metal work.

  Further, a metal work is disposed in the processing space 1, and after the processing space 1 is evacuated, an appropriate gas is introduced into the heated processing space 1, and subsequently, the high-pressure superheated steam is heated into the processing space 1. The present invention relates to a method for treating a surface of a metal work, wherein the oxide film is formed on the surface of the metal work by being introduced.

The selection method of surface treatment of a metal workpiece according to any one of claims 2 to 4, as the gas _He, from _{N 2, H 2, CO 2} , NH 3, C 2 H 2 , or a gas The present invention relates to a method for treating a surface of a metal work, wherein a mixed gas of several kinds of gases is employed.

  Further, in the surface treatment method for a metal work according to any one of claims 2 to 5, a suitable gas is discharged from the processing space 1 by vacuum exhaust before introducing the high-pressure superheated steam. The present invention relates to a surface treatment method for a work.

  The surface treatment method of a metal work according to any one of claims 1 to 6, wherein the treatment space is evacuated after forming the oxide film. is there.

  In addition, it has a heatable processing space 1 for performing a surface treatment of a metal work, further has a vacuum processing mechanism for bringing the processing space 1 into a vacuum state, a gas introduction unit 3 for introducing an appropriate gas into the processing space 1, and The present invention relates to a surface treatment apparatus for a metal work, wherein a steam introduction unit 2 for introducing high-pressure superheated steam is provided in the processing space 1.

  Since the present invention is configured as described above, it is an epoch-making metal work surface treatment method and a metal work surface treatment apparatus exhibiting a function and effect not found in the conventional method.

  Preferred embodiments of the present invention will be briefly described with reference to the drawings, showing the operation of the present invention.

In the case of the surface treatment of a metal work according to the conventional method, the present applicant disposes the metal work in a processing space of a heating furnace and heats the metal work to about 400 ° C., thereby oxidizing FeO or Fe ₂ O _{3 on} the surface of the metal work. Attention was paid to the fact that a film was generated in some places of about 1 to 2 microns, and this oxide film of FeO or Fe ₂ O ₃ was an obstacle to improving the smoothness and durability of a metal product. Without forming an oxide film of FeO or Fe ₂ O _{3 on} the surface of the work, a stable oxide film (triiron tetroxide: Fe ₃ O) useful for improving the smoothness and durability of the metal work. ₄ ) It was found that a higher quality surface film could be obtained by forming only ( ₄ ).

  Therefore, the applicant has repeatedly performed various experiments and studies from this viewpoint, and as a result, completed an extremely epoch-making invention.

That is, the introduction of a gas having a contradictory property at the dew point and a gas such as He, N ₂ , H ₂ , CO ₂ , NH ₃ , C ₂ H ₂ into the furnace is greatly affected by the water vapor. Since dew point adjustment was impossible and steam remained in the furnace, it was considered difficult to combine these gases with steam. However, the present invention has solved this point.

  Specifically, according to the present invention, a metal work is disposed in the processing space 1, and after the processing space 1 is evacuated, high-pressure superheated steam is introduced into the processing space 1 to form an oxide film on the surface of the metal work. Or a metal work is disposed in the processing space 1, then an appropriate gas is introduced into the processing space 1, and then high-pressure superheated steam is introduced into the processing space to oxidize the surface of the metal work. After forming a film or disposing a metal work in the processing space 1 and evacuating the processing space 1, an appropriate gas is introduced into the processing space 1. 1 to form an oxide film on the surface of the metal work.

An oxide film of FeO or Fe ₂ O ₃ was not formed on the surface of the metal workpiece thus obtained, and only the oxide film (triiron tetroxide: Fe ₃ O ₄ ) considered to be useful as described above was used. Was formed, and it was confirmed from the enlarged photographs by a microscope that the porous surface structure was modified (see FIGS. 3, 4, and 5). Note that an oxide film is not formed on the carbide present in the metal work.

  Accordingly, a high quality surface film having excellent smoothness and durability can be obtained, and a high quality metal work can be provided by this surface film.

  As described above, the present invention exerts an epoch-making action and effect not found in the conventional method, and becomes extremely high in commercial value.

  A specific embodiment of the present invention will be described with reference to the drawings.

  The present embodiment is a method for treating a surface of a metal work constituting a metal product such as a cutting tool or a mold, and is realized by the processing apparatus A shown in FIG.

  More specifically, the processing apparatus A has a processing space 1 for performing a surface treatment of a metal work, and is further disposed in the processing space 1 and a vacuum processing mechanism (not shown) for bringing the processing space 1 into a vacuum state. It is configured as a vacuum heating furnace provided with a heating mechanism (not shown) capable of heating the metal work thus formed.

  Further, the processing apparatus A is provided with a steam introduction unit 2 that can introduce high-pressure superheated steam into the processing space 1.

The steam introduction unit 2 is configured to blow and introduce high-pressure superheated steam of about 150 ° C. to 180 ° C. · 4 kg / cm ³ into the processing space 1 at a stretch. Due to the short-time oxidation reaction by the pressurized superheated steam, FeO and Fe ₂ O ₃ are not generated. That is, an intermediate product is apt to be generated by moderate oxidation, and the Fe ₃ O ₄ film is easily peeled off. However, such a problem does not occur due to rapid oxidation.

  Further, pure water is employed as the high-pressure superheated steam. Therefore, by using this high-pressure superheated steam as pure water, a beautiful finished surface with a black luster can be obtained on the surface of the metal work, and harmful chemicals are used like conventional black dye plating. There is no environment-friendly processing.

By controlling the blowing amount of the high-pressure superheated steam, the action of H ₂ for controlling the generation of Fe ₂ O ₃ is promoted, and the reaction of the following chemical formula showing the mechanism of generation of hydrogen hydroxide generated by the decomposition of steam is performed. Since the reaction can be suppressed, the reaction represented by the following chemical formula 2 can be suppressed, and thus, high-purity Fe ₃ O ₄ can be obtained.

また、処理装置Ａには、処理空間１にガスを導入し得るガス導入部３が設けられている。

Further, the processing apparatus A is provided with a gas introduction unit 3 that can introduce a gas into the processing space 1.

  The gas introduction unit 3 includes a first gas introduction unit 3A and a second gas introduction unit 3B, and one type of gas is supplied from one of the first gas introduction unit 3A and the second gas introduction unit 3B. Can be introduced into the processing space 1 or two types of gases can be mixed and introduced into the processing space 1 from both the first gas introduction unit 3A and the second gas introduction unit 3B in accordance with the purpose of the treatment.

In addition, He, N ₂ , H ₂ , CO ₂ , NH ₃ , C ₂ H _2, or the like is employed as a gas introduced from the gas introduction unit 3. Since He is expensive, it is desirable to use a gas other than He.

These gases are used for applying a high-pressure superheated steam from the steam introduction unit 2 to form a base treatment on the surface of the metal work before forming an oxide film on the surface of the metal work. The formation of triiron (Fe ₃ O ₄ ) is promoted.

  It has been confirmed that the introduction of these gases is more effective when introduced intermittently (pulsed) than when introduced uniformly.

  A method for treating the surface of a metal work using the processing apparatus A having the above configuration will be described (see FIG. 2).

First, a metal work (for example, a gear, a drill, etc.) is put into the processing space 1 of the processing apparatus A, and the processing space 1 is evacuated to a vacuum state by a vacuum processing mechanism. Until the vacuum state is reached, the processing space 1 is heated until it reaches about 150 ° C. (t ₁ ) (h ₁ : about 0.5 hour). The conventional method requires a long time because the air is expelled from the processing space 1 by using water vapor. However, in the present embodiment, a vacuum state is created in advance, so that time is not required unlike the conventional method. In addition, _{t 1} may be at room temperature.

Subsequently, an appropriate gas (He, N ₂ , H ₂ , CO ₂ , NH ₃ , C ₂ H ₂ ) is injected into the processing space 1 from the gas introduction unit 3 alone or in a mixture, and is blown into the furnace to a predetermined temperature. The temperature is raised and the temperature is soaked (t ₂ : about 500 to 650 ° C., h ₂ : about 1 to 3 hours). When the appropriate gas is introduced, the processing space 1 is preferably in a vacuum state, but the processing space 1 is not necessarily required to be in a vacuum state (when only the N ₂ gas is introduced).

Subsequently, the water vapor introduction part 2, the processing space 1 _{t 3:} as about 480 ℃ ~650 ℃, _{h 3:} In about 1-3 hours, once the high pressure superheated steam (about 120 ° C. to 160 ° C.) in the treatment space When introduced by blowing (after blowing in a large amount for 5 to 10 minutes and then continuing to blow), an oxide film (triiron tetroxide: Fe ₃ O ₄ ) is formed on the surface of the metal work by a rapid oxidizing action.

When a large amount of H ₂ or NH ₃ is introduced into the processing space 1 as an appropriate gas, the processing space is introduced before the introduction of high-pressure superheated steam (at the point r in FIG. 2) in order to prevent an explosion caused by the introduction of steam. The evacuation of step 1 is performed for about 10 minutes.

  The most important factor for obtaining the thickness of the oxide film is to increase the furnace pressure. This point was confirmed by data showing the relationship between the furnace pressure and the film thickness obtained by the experiment (see FIGS. 6 to 12). From these data, it is understood that the oxide film becomes thicker when the furnace pressure is increased.

Thereafter, a predetermined temperature is maintained for a predetermined time in order to promote the permeation of the oxide film into the internal structure. (It is desirable to carry out t ₄ : about 300 ° C. and h ₄ : about 2 hours in order to remove remaining water vapor and oxidized substances.) ).

Thereafter, or in conjunction may be performed to introduce strong reducing H ₂ with again evacuated or evacuated, the introduction of a strong H ₂ reducing property that with this evacuation or vacuum evacuation, the following new metal workpiece The first vacuum evacuation step when the same surface treatment is performed is performed in the absence of water vapor (in order to keep the processing apparatus A continuous or to reduce the risk of explosion, etc.). , For maintenance reasons.) Therefore, in the case where the surface treatment of the metal work is performed continuously, it is useful to introduce the last vacuum exhaust or the highly reducing H ₂ that is performed together with the vacuum exhaust.

The values of the set temperature in the surface treatment method for a metal workpiece according to the present embodiment _(t 1 _{~t 4)} and time _(h 1 ~h ₄₎ it is in an optimal numerical in forming a high-quality surface film It has been confirmed by experiments that a high-quality surface film is not formed outside the range of the temperature and the time.

An oxide film of FeO or Fe ₂ O ₃ is not formed on the surface of the metal workpiece obtained as described above, and an oxide film (triiron tetroxide: Fe ₃ O ₄₎ called black rust is formed. ) Is formed (approximately 5 microns in film), and the formation of this oxide film makes the metal work excellent in smoothness (lubricity) and durability (abrasion resistance and corrosion resistance). This has been confirmed by the applicant through experiments.

  Since this embodiment is configured as described above, a high-quality metal work excellent in smoothness and durability can be easily and quickly obtained, and a high-quality metal product can be provided from this metal work. It becomes.

  It should be noted that the present invention is not limited to the present embodiment, and a specific configuration of each component can be appropriately designed.

It is explanatory drawing of the surface treatment apparatus of the metal workpiece which concerns on a present Example. It is a schematic explanatory view in the surface treatment method of the metal work concerning this example. 4 is an enlarged photograph of the surface of a metal workpiece subjected to a surface treatment according to the present embodiment. 4 is an enlarged photograph of the surface of a metal workpiece subjected to a surface treatment according to the present embodiment. 4 is an enlarged photograph of the surface of a metal workpiece subjected to a surface treatment according to the present embodiment. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example. 6 is experimental data showing the relationship between the furnace pressure and the film thickness in the surface treatment according to the present example.

Explanation of reference numerals

1 processing space 2 steam introduction section 3 gas introduction section

Claims (8)

  Disposing a metal work in the processing space, evacuating the processing space, and then introducing high-pressure superheated steam into the processing space to form an oxide film on the surface of the metal work; Processing method.   Arranging a metal work in the processing space, subsequently introducing an appropriate gas into the processing space, and subsequently introducing high-pressure superheated steam into the processing space to form an oxide film on the surface of the metal work. Surface treatment method for metal work.   A metal work is disposed in the processing space, and after the processing space is evacuated, an appropriate gas is introduced into the processing space, and then high-pressure superheated steam is introduced into the processing space to oxidize the surface of the metal work. A surface treatment method for a metal work, comprising forming a film.   A metal work is disposed in the processing space, and after the processing space is evacuated, an appropriate gas is introduced into the heated processing space. Subsequently, high-pressure superheated steam is introduced into the heated processing space, and the metal work is introduced. A method for treating a surface of a metal work, comprising forming an oxide film on the surface of the metal workpiece. In the surface treatment method for a metal workpiece according to any one of claims 2 to 4, is selected as the gas _He, from _{N 2, H 2, CO 2} , NH 3, C 2 H 2 , or a gas A surface treatment method for a metal work, wherein a mixed gas of several kinds of gases is employed.   The surface treatment method for a metal work according to any one of claims 2 to 5, wherein an appropriate gas is exhausted from the processing space by vacuum evacuation before introducing the high-pressure superheated steam. Processing method.   7. The surface treatment method for a metal work according to claim 1, wherein the processing space is evacuated after forming the oxide film. It has a heatable processing space for surface treatment of metal work, and further has a vacuum processing mechanism for evacuating the processing space, a gas introduction unit for introducing an appropriate gas into the processing space, and high-pressure heating in the processing space. A surface treatment apparatus for a metal work, comprising a steam introduction section for introducing steam.

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