JP2016501316A - Metal surface treatment apparatus and metal surface treatment method using the same - Google Patents

Abstract

The metal surface treatment apparatus of the present invention is a metal surface treatment apparatus for surface-treating a target metal heated to a temperature at which surface treatment can be performed, and has a shape corresponding to the outer surface shape of the target metal, and the outer surface of the target metal A reaction chamber disposed within a certain interval and containing at least a part of the target metal and a processing gas supply unit for supplying a processing gas necessary for autocatalytic reaction to the target metal side accommodated in the reaction chamber. And the metal surface treatment method using this has a shape corresponding to the outer surface shape of the target metal, and is disposed within a certain distance from the outer surface of the target metal, and accommodates at least a part of the target metal. And a step of supplying a processing gas into the reaction chamber through a processing gas supply unit to form a processing gas layer on the target metal by an autocatalytic reaction. [Selection] Figure 1

Description

The present invention relates to a metal surface treatment apparatus and a metal surface treatment method using the same, and more specifically, a treatment gas layer is formed on a target metal by an autocatalytic reaction, and the wear resistance and corrosion resistance are excellent. The present invention relates to a metal surface treatment apparatus having a high surface hardness and a metal surface treatment method using the same.

The field of advanced hybrid processing technology, which is a promising future technology, has recently been researched and developed from various viewpoints, which can be improved to improve the performance of existing products, or product development with new concepts. It is used for.

Also, in this advanced hybrid processing technology field, surface treatment technology for improving the surface properties of metals to enhance wear resistance, corrosion resistance and fire resistance is actively researched. Therefore, the demand is expected to increase explosively in industrial fields such as automobiles and molds.

Conventionally, gas nitriding has been widely applied for metal surface treatment. The low-temperature nitriding method that has been widely used until now is a low-temperature nitriding method, but this requires a long processing time, resulting in a large drop in yield and a slight metal surface treatment effect. There is a problem. In particular, in the case of stainless steel, a decrease in nitriding ability due to a natural oxide film may occur.

Therefore, there is a demand for a method for solving such problems, but no metal surface treatment technology has been proposed so far that maintains high productivity and at the same time has excellent surface treatment quality. It is a fact.

The present invention is an invention devised to solve the above-mentioned problems of the prior art, and a metal surface treatment apparatus capable of maintaining high productivity and at the same time having excellent surface treatment quality, and the present invention. This is to provide a metal surface treatment method utilizing the above.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

A metal surface treatment apparatus of the present invention for solving the above problems is a metal surface treatment apparatus for surface-treating a target metal heated to a temperature at which surface treatment is possible, and has a shape corresponding to the outer surface shape of the target metal. And a reaction chamber that is disposed within a certain distance from the outer surface of the target metal and that supplies at least a part of the target metal and a processing gas necessary for the autocatalytic reaction to the target metal side stored in the reaction chamber A processing gas supply unit is included.

The reaction chamber may be formed such that the inner surface of the reaction chamber and the outer surface of the target metal have an interval of 50 mm or less in a state where the target metal is accommodated.

In addition, a passage hole through which the processing gas passes may be formed in the reaction chamber.

The heating chamber may further include a heating unit that heats the inside of the reaction chamber.

The apparatus may further include an interval adjusting unit that adjusts an interval between the reaction chamber and the outer surface of the target metal in a state where the target metal is accommodated.

The reaction chamber may include an upper plate and a lower plate that is spaced apart from the upper plate by a predetermined distance, and the distance adjusting unit may be formed to slide up and down the upper plate and the lower plate. it can.

In addition, an external chamber in which the reaction chamber is accommodated and an accommodating space capable of being sealed can be further included.

And before the said target metal is accommodated in the reaction chamber, the preheating part which preheats the said target metal can be further included.

In addition, a transfer unit that transfers the target metal so as to pass through the reaction chamber may be further included.

In addition, both sides of the reaction chamber may be opened, and the transfer unit may be provided on both sides of the reaction chamber.

In addition, the transfer unit may be provided to seal both open sides of the reaction chamber.

The transfer unit may include a transfer member that transfers the target metal by rotating in contact with the target metal.

The transfer member is formed to rotate while being in contact with the reaction chamber. The transfer member can transfer the target metal and simultaneously seal both sides of the reaction chamber.

The reaction chamber may include a flow space in which a processing gas flows and a supply hole that communicates with the flow space and supplies the processing gas in the direction of the target metal.

In addition, the metal surface treatment method of the present invention for solving the above-described problem has a shape corresponding to the outer surface shape of the target metal, and is disposed within a certain distance from the outer surface of the target metal, and is at least one of the target metal. Positioning a target metal in a reaction chamber containing a portion, and supplying a processing gas into the reaction chamber through a processing gas supply unit to form a processing gas layer on the target metal by an autocatalytic reaction. .

In the step of positioning the target metal in the reaction chamber, the inner surface of the reaction chamber and the outer surface of the target metal have an interval of 50 mm or less.

In the step of forming the process gas layer, the process gas may be supplied at a pressure of 0.5 to 20 kg / cm ² .

The metal surface treatment apparatus of the present invention and the metal surface treatment method using the same for solving the above-described problems have the following effects.
First, there is an advantage that a metal having excellent wear resistance and corrosion resistance and high surface hardness can be provided.
Second, there is an advantage that metal surface treatment can be performed intensively in a short time.
Third, the yield is greatly increased, the productivity is increased, and mass production is possible.
Fourth, the structure of the metal surface treatment apparatus is simple, the cost required for constructing the equipment is reduced, and the maintenance cost is also reduced.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the claims.

The perspective view which showed the figure of the metal surface treatment apparatus by 1st Example of this invention. Sectional drawing which showed the cross section of the metal surface treatment apparatus by 1st Example of this invention The perspective view which showed the figure of the metal surface treatment apparatus by 2nd Example of this invention. Sectional drawing which showed the cross section of the metal surface treatment apparatus by 2nd Example of this invention Sectional drawing which showed the structure of the metal surface treatment apparatus by 3rd Example of this invention Sectional drawing which showed the structure of the metal surface treatment apparatus by 4th Example of this invention Sectional drawing which showed the structure of the metal surface treatment apparatus by 5th Example of this invention Sectional drawing which showed the structure of the metal surface treatment apparatus by 6th Example of this invention Sectional drawing which showed the structure of the metal surface treatment apparatus by 7th Example of this invention Sectional drawing which showed the figure of the transfer part in detail in the metal surface treatment apparatus by 7th Example of this invention. In the metal surface treatment method according to the present invention, a conceptual diagram showing an autocatalytic reaction when a processing gas is provided to a target metal. In the metal surface treatment method according to the present invention, when the treatment gas is nitrogen, a graph and an optical micrograph showing the result of the surface treatment according to the separation distance In the metal surface treatment method according to the present invention, when the treatment gas is nitrogen, a graph and a photomicrograph showing the result of the surface treatment by temperature In the metal surface treatment method according to the present invention, when the treatment gas is nitrogen, a graph and an optical micrograph showing the surface treatment results when the treatment time is set short SEM cross-sectional photograph nitrided according to Example 4 of the present invention, and drawings showing components of nitrogen, chromium, and iron that are elements constituting the nitrided layer In the metal surface treatment method according to the present invention, when the treatment gas is ammonia, a graph showing the result of the surface treatment according to temperature and an optical micrograph In the metal surface treatment method according to the present invention, when the treatment gas is ammonia, a graph and an optical micrograph showing the surface treatment result when the treatment time is set short

FIG. 1 is a perspective view illustrating a metal surface treatment apparatus according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a cross section of the metal surface treatment apparatus according to the first embodiment of the present invention. .

As shown in FIGS. 1 and 2, the metal surface treatment apparatus according to the first embodiment of the present invention includes a reaction chamber 100 and a treatment gas supply unit.

The reaction chamber 100 has a shape corresponding to the shape of the outer surface of the target metal M, is disposed within a certain distance from the outer surface of the target metal M, and is provided to accommodate at least a part of the target metal.

That is, the inner surface of the reaction chamber 100 is provided so as to wrap the target metal M in a state where the target metal M is inserted into the reaction chamber 100 while being separated from the outer surface of the target metal M by a predetermined distance. Can be determined by the shape.

In the case of the present embodiment, the target metal M is formed in a circular shape in cross section, and the inside of the reaction chamber 100 is also formed in a corresponding shape, and the inner surface of the reaction chamber 100 has the target metal M inserted therein. It is formed to have a constant separation distance from each surface of M as a whole.

In this state, the processing gas supply unit supplies a processing gas necessary for the autocatalytic reaction to the target metal M housed in the reaction chamber 100, and the configuration of the processing gas supply unit is not limited thereto. .

For example, the processing gas supply unit may allow the processing gas to flow into the reaction chamber 100 through the open side of the reaction chamber 100 or may be provided in the reaction chamber 100. The processing gas can be directly transmitted to the target metal M from the predetermined position.

Meanwhile, the processing gas may be various gases used for metal surface treatment. For example, the processing gas includes nitrogen, ammonia, carbon and the like.

In the case of the present embodiment, although not shown in the drawing, the reaction chamber 100 is further included, and an external chamber in which a sealable storage space is formed is further included. The reaction chamber 100 has a passage hole 110 through which the processing gas passes. Is formed. In other words, the processing gas supply unit can supply the processing gas to the sealed housing space of the external chamber, and form the inside of the housing space in a processing gas atmosphere. As a result, the processing gas flows into the target metal M through the passage hole 110 of the reaction chamber 100.

At this time, a plurality of the through holes 110 may be arranged at a uniform interval along the surface of the reaction chamber 100, and thereby the processing gas can be uniformly supplied to the entire surface of the target metal M.

In addition, the metal surface treatment apparatus according to the present invention may further include a heating unit that heats the inside of the reaction chamber 100. The heating unit can heat the target metal M to a temperature suitable for the surface treatment, or when the target metal M is introduced into the reaction chamber 100 in a preheated state, the temperature is set. Can be maintained. The heating unit may be provided inside or outside the reaction chamber 100 or on both sides.

Furthermore, the metal surface treatment apparatus according to the present invention may further include a preheating unit that preheats the target metal before the target metal M is accommodated in the reaction chamber 100.

At this time, the temperature in the reaction chamber 100 can be adjusted according to the material properties of the target metal M. For example, when the processing gas is nitrogen and the target metal M is stainless steel, it can be heated to about 900 to about 1200 ° C. When surface treatment is performed at a temperature of less than about 900 ° C., the activation energy barrier of nitrogen cannot be exceeded, and when about 1200 ° C. is exceeded, the material is not economical in terms of physical properties and heat consumption. Because there is. Further, the processing time of the target metal M can be adjusted by the temperature of the target metal M.

The processing gas supply unit may supply the processing gas into the reaction chamber 100 at a pressure of about 0.5 to about 20 kg / cm ² . When processing gas is supplied at a pressure of less than about 0.5 kg / cm ² , it becomes difficult for the processing gas to naturally diffuse into the target metal M due to the low gas pressure, and the driving force (Driving Force) due to the pressure gradient is low. This makes it difficult to penetrate the processing gas. Further, when the processing gas is supplied at a pressure exceeding about 20 kg / cm ^2, there may be a problem that the target metal M is prevented from being nitrided by a high gas pressure.

At the same time, the target metal M may be surface-treated while being fixed in the reaction chamber 100, or the surface treatment may be performed while moving in the reaction chamber 100 through a separate transfer unit. Of course, the form of the transfer section is not limited.

On the other hand, in this embodiment, the reaction chamber 100 is configured to adjust the distance between the inner surface of the reaction chamber 100 and the outer surface of the target metal M in various ways while the target metal M is accommodated. It is possible to easily adjust the depth, concentration, and area of the permeation layer of the M processing gas.

In particular, the target metal M and the inner surface of the reaction chamber 100 may be formed to have an interval of 50 mm or less. This is because when the distance between the target metal M and the inner surface of the reaction chamber 100 exceeds 50 mm, the density of the processing gas is lowered and the processing effect may be reduced.

FIG. 3 is a perspective view illustrating a metal surface treatment apparatus according to a second embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating a cross section of the metal surface treatment apparatus according to the second embodiment of the present invention.

As shown in FIGS. 3 and 4, in the case of the present embodiment, the cross section of the target metal M is formed in an H shape. In this case as well, the inside of the reaction chamber 200 is formed in a shape corresponding to the target metal M, and the inner surface of the reaction chamber 200 is entirely separated from each surface of the target metal M with the target metal M inserted. Is formed. A plurality of passage holes 210 are formed in the reaction chamber 200.

As a result, the effect of the surface treatment can be increased, and the surface treatment with uniform quality can be performed as a whole.

In the case of the present embodiment, matters such as the processing gas supply unit, the heating unit, and the transfer unit described above may be applied in the same way, and this is also the case in the embodiment described below. The overlapping description is omitted.

FIG. 5 is a sectional view showing the structure of a metal surface treatment apparatus according to a third embodiment of the present invention.

In the third embodiment of the present invention, the target metal M is formed in a plate shape, and the reaction chamber 300 includes an upper plate and a lower plate spaced apart from the upper plate by a predetermined distance. Then, the processing gas supply unit supplies the processing gas to the surface of the target metal M through the flow channel 310 formed in the upper plate and the lower plate. At this time, the flow channel 310 is branched into a plurality of paths, and the processing gas can be uniformly supplied to the entire surface of the target metal M.

That is, in such a case, since it is possible to omit the provision of a separate external chamber by sealing both sides of the reaction chamber 300, there is an advantage that the equipment is simplified.

FIG. 6 is a sectional view showing the structure of a metal surface treatment apparatus according to a fourth embodiment of the present invention.

In the case of the fourth embodiment of the present invention, the target metal M is formed in a plate shape as in the case of the third embodiment described above. The reaction chamber 400 also includes an upper plate and a lower plate spaced a predetermined distance from the upper plate.

In addition, the present embodiment further includes an interval adjusting unit 420 that adjusts an interval between the reaction chamber 400 and the outer surface of the target metal M. In detail, the distance adjusting unit 420 may be formed to slide the upper plate and the lower plate up and down.

That is, in such a case, the processing gas is supplied through the passage hole 410 in a state where the distance between the reaction chamber 400 and the outer surface of the target metal M is fluidly adjusted to induce a desired result, A suitable arrangement interval can be set depending on the characteristics or the concentration of the processing gas. In addition, even when the shape or thickness of the target metal is irregular, the interval adjustment unit 420 can be used to adjust the interval between the upper plate and the lower plate.

FIG. 7 is a sectional view showing the structure of a metal surface treatment apparatus according to a fifth embodiment of the present invention.

As shown in FIG. 7, the metal surface treatment apparatus according to the fifth embodiment of the present invention includes a reaction chamber 500, a process gas supply unit, and a transfer unit 530.

The transfer unit 530 is a component that transfers the target metal M so as to pass through the reaction chamber 510. The transfer unit 530 is not limited in its form and transfer method, and any form that can transfer the target metal M can be applied.

In this embodiment, both sides of the reaction chamber 500 are formed to be opened, and the transfer unit 530 is provided on both sides of the reaction chamber 500 that are opened. In particular, the transfer unit 530 includes a transfer member that transfers the target metal M by rotating in direct contact with the target metal M.

When the transfer unit 530 is formed in this way, the transfer of the target metal can be precisely controlled by the transfer unit 530, and thus there is an advantage that a uniform surface treatment result can be obtained.

FIG. 8 is a sectional view showing the structure of a metal surface treatment apparatus according to the sixth embodiment of the present invention.

As shown in FIG. 8, the metal surface treatment apparatus according to the sixth embodiment of the present invention includes a reaction chamber 600, a process gas supply unit, a transfer unit 630, and a gap adjustment unit 640.

In this embodiment, the transfer unit 630 includes one or more transfer members 634. The transfer member 634 is formed to transfer the target metal by rotating in contact with the target metal M.

The transfer member 634 is accommodated in the transfer unit housing 632 and is configured to rotate while being in contact with the reaction chamber 600 to transfer the target metal M and at the same time on both sides of the reaction chamber 600. Is formed to be hermetically sealed.

In this embodiment, the reaction chamber 600 includes an upper plate and a lower plate separated from the upper plate by a predetermined distance, and an interval adjusting unit that adjusts an interval between the reaction chamber 600 and the outer surface of the target metal. 640 is further included. In detail, the distance adjusting unit 640 may be formed to slide the upper plate and the lower plate up and down.

That is, in such a case, in a state where the distance between the reaction chamber 600 and the outer surface of the target metal is fluidly adjusted, a processing gas is supplied through the supply hole 610 to induce a desired result, A suitable arrangement interval can be set depending on the characteristics or the concentration of the processing gas. In addition, even when the shape or thickness of the target metal is irregular, the interval adjustment unit 640 can be used to adjust the interval between the upper plate and the lower plate.

FIG. 9 is a sectional view showing the structure of a metal surface treatment apparatus according to the seventh embodiment of the present invention.

As shown in FIG. 9, the metal surface treatment apparatus according to the first embodiment of the present invention includes a reaction chamber 700 and a treatment gas supply unit.

In this embodiment, the reaction chamber 700 supplies a processing space in the direction of the target metal M, which is in communication with the flow space S and a flow space S in which a processing gas necessary for the autocatalytic reaction of the target metal flows. Includes holes 710.

That is, in the case of the present embodiment, since the flow space S is formed in the reaction chamber 700, only the space arranged with the target metal M through the supply hole 710 can be formed in the processing gas atmosphere, and a separate external chamber can be formed. There is an advantage that is not necessary.

In the case of the present embodiment, the target metal M is formed in a plate shape, and the inside of the reaction chamber 700 is also formed in a shape corresponding thereto. The inner surface of the reaction chamber 700 is formed to have a certain separation distance from each surface of the target metal M in a state where the target metal M is inserted.

In this state, the processing gas supply unit supplies the processing gas necessary for the autocatalytic reaction to the flow space S, and the form of the processing gas supply unit is not limited. In the case of the present embodiment, the processing gas supply unit can supply the processing gas to the flow space S through the supply flow path 720.

FIG. 10 is a cross-sectional view showing in detail the shape of the transfer part in the metal surface treatment apparatus according to the seventh embodiment of the present invention.

As shown in FIG. 10, the transfer unit of the metal surface treatment apparatus according to the present embodiment includes one or more transfer members 734. The transfer member 734 is formed to transfer the target metal by rotating in contact with the target metal M.

In the case of the present embodiment, the transfer member 734 is accommodated in the transfer unit housing 732 and is configured to rotate while being in contact with the reaction chamber 700 to simultaneously transfer the target metal M. The reaction chamber 700 is formed to seal both sides.

As mentioned above, although each Example of the metal surface treatment apparatus of this invention was described, below, the principle of surface treatment and the experimental result performed based on this are demonstrated.

FIG. 11 is a conceptual diagram showing an autocatalytic reaction when a processing gas is provided to a target metal in the metal surface treatment method according to the present invention. In this drawing, the case where the processing gas is nitrogen is illustrated.

Nitrogen gas supplied from the processing gas supply unit repeatedly hits between the heated target metal and the reaction chamber. At this time, the target metal acting as an autocatalyst exceeds the activation energy of nitrogen. The nitrogen gas (N2) is decomposed into nitrogen groups (N). Nitrogen groups (N) may enter the surface of the target metal to form a nitride layer.

Thereafter, the nitrogen gas (N2) that is continuously supplied is changed to nitrogen groups (N) that can form a nitride layer on the target metal, and the speed of nitriding treatment is increased. Therefore, there is an advantage that the formation speed of the nitride layer is increased and the corrosion resistance and mechanical properties can be improved by meeting the known element or additive element of the target metal. Further, the metal surface treatment can be performed intensively within a short time, and the production efficiency can be maximized.

In addition, the surface-treated metal of the present invention has a high surface hardness and can withstand high loads, and is not easily damaged by friction. Therefore, as a material for power generation turbines, automotive steel plates, wind propellers, etc. Even if used for a long time, it can maintain an excellent state. In addition, the excellent corrosion resistance formed during the surface treatment can be applied to rescue materials such as marine plants, desalination facilities, and chemical facilities exposed to corrosive environments.

Below, the experimental result obtained by performing the surface treatment of a metal according to each condition is demonstrated.

[Experiment 1]
FIG. 12 is a graph showing a surface treatment result according to a separation distance and a photograph of an optical microscope when the treatment gas is nitrogen in the metal surface treatment method according to the present invention.

In this experiment, the treatment gas was nitrogen, the target metal was stainless steel 430, and the surface treatment was performed at a partial pressure of 1 kg / cm ² and a temperature condition of 1100 ° C. for 60 minutes. The hardness according to the depth of the metal surface was measured by changing the separation distance between the target metal and the inner surface of the reaction chamber to 0.1 mm and 0.5 mm.

As shown in the graph, when the surface treatment is performed by the metal surface treatment method according to the present invention, it can be confirmed that the hardness is remarkably improved as compared with the conventional general surface treatment method. In other words, when the separation distance between the target metal and the inner surface of the reaction chamber is 0.1 mm and 0.5 mm, the hardness is remarkably improved when the depth of the metal surface is 400 μm or less, and the conventional surface treatment is performed even when the depth exceeds 400 μm. It can be confirmed that high hardness is maintained as compared with the method.

Further, in the optical micrograph shown at the bottom of the drawing, the left side represents the surface of the metal surface-treated by the conventional surface treatment method, and the right side is the surface treatment by the surface treatment method according to the present invention. It represents the surface of a metal that has been treated.

As shown in the figure, in the case of the left side, no martensite organization is confirmed on the metal surface, but in the case of the right side, it can be confirmed that the martensite organization is formed on the metal surface. That is, according to this experiment, it can be proved that the surface hardness of the metal is remarkably improved by the metal surface treatment method of the present invention as compared with the conventional general metal surface treatment.

[Experiment 2]
FIG. 13 is a graph showing a result of surface treatment according to temperature and a photograph of an optical microscope when the treatment gas is nitrogen in the metal surface treatment method according to the present invention.

In this experiment, the treatment gas is nitrogen, the target metal is stainless steel 430, and the surface treatment is performed for 60 minutes under the condition that the separation distance between the target metal and the inner surface of the reaction chamber is set to 0.1 mm at a partial pressure of 1 kg / cm ^2. Went.

And the hardness by the depth of a metal surface was measured, changing the temperature of an object metal into 900 degreeC, 1000 degreeC, and 1100 degreeC.

As shown in the graph, it can be confirmed that the hardness is remarkably improved at 1000 ° C. or higher compared to the result of the experiment at 900 ° C. That is, when the temperature of the target metal is 1000 ° C. or 1100 ° C., it appears that the hardness of the metal surface is significantly improved when the depth of the metal surface is 200 μm or less. It can be confirmed that a high hardness is maintained as compared with the above experiment.

In the optical micrograph shown at the bottom of this drawing, the left side represents the metal surface when the temperature of the target metal is 900 ° C., and the right side is the temperature of the target metal of 1000 ° C. The metal surface of the case is shown.

As shown in the figure, the depth of the martensite structure on the metal surface is about 30 μm in the case of the left side, and the depth of the martensite structure on the metal surface is about 150 μm in the case of the right side. That is, according to this experiment, it can be proved that the surface hardness of the metal is remarkably improved at a temperature of 1000 ° C. or higher.

[Experiment 3]
FIG. 14 is a graph and a photo of an optical microscope showing the surface treatment result when the treatment time is set short when the treatment gas is nitrogen in the metal surface treatment method according to the present invention.

In this experiment, the treatment gas is nitrogen, the target metal is stainless steel 430, and the surface treatment is performed for 10 minutes under the condition that the separation distance between the target metal and the inner surface of the reaction chamber is set to 0.1 mm at a partial pressure of 1 kg / cm ^2. Did.

And the temperature of the object metal was set to the high temperature of 1100 degreeC and 1200 degreeC, and the hardness by the depth of a metal surface was measured.

As shown in the graph, it can be confirmed that the hardness is remarkably improved as compared with the conventional metal surface treatment method at both 1100 ° C. and 1200 ° C. That is, when the temperature of the target metal is 1000 ° C. or 1100 ° C., it can be confirmed that the hardness is remarkably improved when the depth of the metal surface is 200 μm or less.

Also, in the optical micrograph shown at the bottom of the drawing, the left side represents the metal surface when the temperature of the target metal is 1100 ° C., and the right side is the temperature of the target metal of 1200 ° C. The metal surface of the case is shown.

As shown in the figure, it can be confirmed that the depth of the martensite structure on the metal surface is about 130 μm in the case of the left side, and the depth of the martensite structure on the metal surface is about 200 μm in the case of the right side. That is, according to this experiment, when surface treatment is performed at a high temperature of 1100 ° C. or higher, it can be proved that the surface hardness of the metal is remarkably improved even within a short time of about 10 minutes. Assuming that the processing time is overwhelmingly shortened compared to the conventional case, it is possible to expect a yield increase several times.

FIG. 15 is a cross-sectional photograph of an SEM nitrided by this experiment and shows the components of nitrogen, chromium, and iron that are elements constituting the nitride layer. Through this, it can be confirmed that not only the surface of the plate-like stainless steel 430 but also the inside contains nitrogen.

[Experimental Example 4]
FIG. 16 is a graph showing a result of surface treatment according to a separation distance and a photograph of an optical microscope when the treatment gas is ammonia in the metal surface treatment method according to the present invention.

In this experiment, the treatment gas was made of ammonia, the target metal was made of stainless steel 430, and the surface treatment was performed at a partial pressure of 1 kg / cm ² and a temperature condition of 600 ° C. for 60 minutes. The hardness according to the depth of the metal surface was measured by changing the separation distance between the target metal and the inner surface of the reaction chamber to 0.1 mm and 0.5 mm.

As shown in the graph, when the surface treatment is performed by the metal surface treatment method according to the present invention, it can be confirmed that the hardness is remarkably improved as compared with the conventional general surface treatment method. That is, when the separation distance between the target metal and the inner surface of the reaction chamber is 0.1 mm and 0.5 mm, it can be confirmed that the hardness is remarkably improved when the depth of the metal surface is 25 μm or less.

Further, in the optical micrograph shown at the bottom of the drawing, the left side represents the surface of the metal surface-treated by the conventional surface treatment method, and the right side is the surface treatment by the surface treatment method according to the present invention. It represents the surface of a metal that has been treated.

As shown in the drawing, in the case of the left side, no martensite organization is confirmed on the metal surface, but in the case of the right side, it can be confirmed that the martensite organization is formed on the metal surface. That is, according to this experiment, it can be proved that the surface hardness of the metal is remarkably improved by the metal surface treatment method of the present invention as compared with the conventional general metal surface treatment.

[Experimental Example 5]
FIG. 17 is a graph showing the result of surface treatment according to temperature and a photograph of an optical microscope when the treatment gas is ammonia in the metal surface treatment method according to the present invention.

In this experiment, the treatment gas is ammonia, the target metal is stainless steel 430, and the surface treatment is performed for 60 minutes under the condition that the separation distance between the target metal and the inner surface of the reaction chamber is set to 0.1 mm at a partial pressure of 1 kg / cm ^2. Did.

And the hardness of the metal surface by depth was measured, changing the temperature of object metal into 400 degreeC, 500 degreeC, and 600 degreeC.

As shown in the graph, it can be confirmed that the hardness is remarkably improved at 600 ° C. as compared with the results of experiments at 400 ° C. and 500 ° C. That is, when the temperature of the target metal is 600 ° C., it is confirmed that the hardness is remarkably improved when the depth of the metal surface is 25 μm or less, and the hardness is maintained higher than that of other experiments even at a depth exceeding 25 μm. it can.

In the optical micrograph shown at the bottom of the drawing, the left side represents the metal surface when the temperature of the target metal is 400 ° C., and the right side is the temperature of the target metal is 500 ° C. The metal surface of the case is shown.

As shown in the drawing, it can be confirmed that the depth of the martensite structure on the right metal surface is deeper than the depth of the martensite structure on the left metal surface. That is, according to this experiment, it can be proved that the surface hardness of the metal is remarkably improved as the temperature increases.

As described above, the preferred embodiments according to the present invention have been described. However, in addition to the above-described embodiments, the present invention may be embodied in other specific forms without departing from the spirit and scope thereof. Is obvious to those with ordinary knowledge of the technology. Thus, the foregoing embodiments are to be regarded as illustrative rather than restrictive, and the present invention is not limited to the foregoing description, but is modified within the scope of the claims and their equivalents. You can also.

Claims (17)

In a metal surface treatment apparatus for surface-treating a target metal heated to a temperature capable of surface treatment,
A reaction chamber having a shape corresponding to the outer surface shape of the target metal, disposed within a certain distance from the outer surface of the target metal, and containing at least a part of the target metal; and an object accommodated in the reaction chamber A processing gas supply unit that supplies processing gas necessary for autocatalytic reaction to the metal side;
Metal surface treatment equipment including. The reaction chamber comprises
The metal surface treatment apparatus according to claim 1, wherein an inner surface of the reaction chamber and an outer surface of the target metal are formed so as to have an interval of 50 mm or less in a state where the target metal is accommodated. The metal surface treatment apparatus according to claim 1, wherein a passage hole through which the processing gas passes is formed in the reaction chamber. The metal surface treatment apparatus according to claim 1, further comprising a heating unit that heats the inside of the reaction chamber. The metal surface treatment apparatus according to claim 1, further comprising an interval adjusting unit that adjusts an interval between the reaction chamber and an outer surface of the target metal in a state where the target metal is accommodated. The reaction chamber includes an upper plate and a lower plate spaced a predetermined distance from the upper plate,
The metal surface treatment apparatus according to claim 5, wherein the distance adjusting unit is formed to slide the upper plate and the lower plate up and down. The metal surface treatment apparatus according to claim 1, further comprising an external chamber in which the reaction chamber is accommodated and an accommodating space capable of being sealed is formed. The metal surface treatment apparatus according to claim 1, further comprising a preheating unit that preheats the target metal before the target metal is accommodated in the reaction chamber. The metal surface treatment apparatus according to claim 1, further comprising a transfer unit configured to transfer the target metal so as to pass through the reaction chamber. Both sides of the reaction chamber are formed to be open,
The metal surface treatment apparatus according to claim 9, wherein the transfer unit is provided on both open sides of the reaction chamber. The metal surface treatment apparatus according to claim 10, wherein the transfer unit is provided to seal both open sides of the reaction chamber. The transfer unit is
The metal surface treatment apparatus according to claim 10, further comprising a transfer member configured to transfer the target metal by rotating in contact with the target metal. The transfer member is
The metal surface treatment apparatus according to claim 12, wherein the metal surface treatment apparatus is configured to rotate while being in contact with the reaction chamber to transfer the target metal and at the same time to seal both sides of the reaction chamber. The reaction chamber comprises
The metal surface treatment apparatus according to claim 1, comprising a flow space in which a processing gas flows, and a supply hole that communicates with the flow space and supplies the processing gas toward the target metal. Positioning the target metal in a reaction chamber that has a shape corresponding to the outer surface shape of the target metal, is disposed within a certain distance from the outer surface of the target metal, and accommodates at least a part of the target metal; Supplying a processing gas into the reaction chamber through a gas supply unit to form a processing gas layer by autocatalytic reaction on the target metal;
A metal surface treatment method comprising: Positioning the target metal in the reaction chamber comprises:
The metal surface treatment method according to claim 15, wherein an inner surface of the reaction chamber and an outer surface of the target metal have an interval of 50 mm or less. Forming the process gas layer comprises:
The metal surface treatment method according to claim 15, wherein the treatment gas is supplied at a pressure of 0.5 to 20 kg / cm ² .

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