KR101807501B1 - A nitriding furnace - Google Patents

Abstract

The present invention relates to a nitriding furnace comprising: an outer casing portion; a port positioned inside the outer casing portion; and a circulation fan portion positioned below the outer casing portion, wherein the outer casing portion includes an outer casing having an upper opening and a lid opening and closing an upper portion of the opened outer casing. Accordingly, the present invention is able to easily circulate nitrogen gas and process gas, used in nitriding heat treatment, in a heat treatment furnace.

Description

{A NITRIDING FURNACE}

The present invention relates to a nitriding furnace, and more particularly, to a nitriding furnace in which a nitrogen gas and a process gas can be easily circulated within a heat treatment furnace.

Nitriding is a surface treatment technique in which activated nitrogen is diffused into a steel to obtain a hardened nitrided layer on a steel surface.

When such nitriding is carried out in steel, it is widely used for precision parts, automobile parts, and molds because it can be treated at low temperature below the transformation point, improving wear resistance, fatigue resistance, high temperature strength and corrosion resistance.

In addition, nitriding improves the adhesion of the coating layer and is excellent in hardening of the undercoat layer, and thus application to the complex treatment is increasing.

On the other hand, nitriding has a wide range of applied steel in comparison with carburizing, and the treatment temperature is also in the range of 850 to 950 ° C for carburizing, but in the range of 460 to 600 ° C for nitriding, and further heat treatment and post treatment are not necessary.

And the depth of hardening is 0.4 ~ 1.5mm deep in carburizing, but it is characterized by thinness of 0.01 ~ 0.03mm in nitriding. Impact resistance (toughness) is also poor in carburizing but nitriding is common.

Particularly, while the deformation is largely carburized, the nitriding is very small due to the low-temperature process, and the corrosion resistance is the high carbon content in the case of carburizing, which is usually caused by stress corrosion cracking. However, the corrosion resistance is improved by improving the corrosion resistance of the low carbon steel, It is also better than carburizing.

Nitriding is largely divided into gas nitriding, salt bath nitriding, and ion nitriding.

The above-mentioned gas nitriding has advantages of high hardness, abrasion resistance, fatigue strength, large capacity, and restriction of shape, but it is disadvantageous in that it is difficult to control the use of ammonia (toxic gas), takes a long time, and requires exclusive steel.

The salt bathing is advantageous in that it can be applied to any shape in a short period of time, with no squeeze resistance, no fatigue strength, no restriction on the type of steel, and a low equipment cost. However, And there is a problem that the hardness of the material during the repeated nitriding is lowered.

Although the above nitriding is advantageous in that nitriding property, process control, easiness of phase control, and N 2 gas are used, there is a problem in that it is difficult to nitride the products (nitriding objects) There are disadvantages.

Conventional nitriding heat treatment furnaces are used for nitriding products, but conventional nitriding heat treatment furnaces can not easily discharge the air remaining in the ports to the outside before nitriding heat treatment, thereby causing oxidation of the nitriding object.

Also, there is a problem in that oxidation may be generated in the nitriding object due to the inflow of air during the process of cooling and re-flowing the heated nitrogen in the port.

Further, there is a problem that the nitrogen gas and the process gas used in the nitriding heat treatment are not easily circulated in the heat treatment furnace.

Korean Patent Registration No. 10-414542

SUMMARY OF THE INVENTION It is an object of the present invention to provide a nitriding furnace in which a nitrogen gas and a process gas used in a nitriding heat treatment can be easily circulated in a heat treatment furnace.

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

In order to solve the above-mentioned problems, A port located inside the out casing portion; And a circulation fan unit disposed at a lower portion of the outcasing unit. The outcasing unit includes an outer casing having an upper opening and a lid opening and closing an upper portion of the opened outer casing.

Further, the present invention may further include an ingaking portion located inside the port, wherein the ingning portion includes an ingress portion having an upper portion and a lower portion opened and communicating with the interior of the port, And an auxiliary lid connected to the lid for opening and closing the upper portion of the intake. The circulating fan unit includes a circulation fan located inside the port and a motor for driving the circulation fan, To provide a nitride furnace.

In addition, the present invention provides a nitrogen gas purifier comprising: a nitrogen gas supply unit for supplying nitrogen to the port; And a process gas supply unit for supplying a process gas to the port, wherein the nitrogen gas supply unit includes a nitrogen gas supply pipe having one end located inside the port, Wherein one end of the nitrogen gas supply pipe and one end of the process gas supply pipe provide a nitriding path located at a lower portion of the circulation fan.

Further, the present invention further includes a cooling section for cooling the heated nitrogen in the port and supplying the cooled nitrogen to the port, wherein the cooling section has a first cooling pipe, one end of which passes through the out casing and communicates with the inside of the port, ; A quadrature blower connected to the other end of the first cooling pipe; A heat exchanger connected between both ends of the first cooling pipe; And a second cooling pipe connected at one end to the vacuum blower and at the other end to communicate with the exhaust pipe.

In addition, the present invention provides a nitriding furnace in which N ₂ or N ₂ + CO ₂ gas is supplied to the nitrogen gas supply unit, and NH ₃ gas is introduced into the process gas supply unit.

Further, the present invention is characterized in that the lid includes: a gas inflow portion located on a lower surface of the lid and located in an outer region of the lid; And a gas outlet located at a bottom surface of the lid and located in a central region of the lid, the gas entering the outer area of the lid where the gas inlet is located, and the gas outlet of the lid To provide a nitrided furnace exhausted to the central region.

Further, the present invention is characterized in that the gas inlet includes a plurality of gas inlets and a gas inlet partition defining the plurality of gas inlets,

The gas discharge portion includes a plurality of gas discharge ports and a gas discharge port partition for partitioning the plurality of gas discharge ports.

According to the present invention as described above, the nitrogen gas and the process gas used in the nitridation heat treatment can be easily circulated within the heat treatment furnace.

The present invention also provides a nitrification furnace of a nitrogen circulation cooling system for preventing the oxidation of an object to be nitrided by blocking air infiltration into a port in which the object to be nitrided is contained and for rapidly cooling the object to be nitrided can do.

1 and 2 are schematic cross-sectional views showing a nitride furnace according to the present invention.
Fig. 3 is a schematic bottom view showing a lid of a nitriding furnace according to the present invention, Fig. 4 is a schematic sectional view showing a lid of a nitriding furnace according to the present invention, Fig. 5 is a cross- 1 is a schematic view for explaining a flow.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. &Quot; and / or "include each and every combination of one or more of the mentioned items. ≪ RTI ID = 0.0 >

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" And can be used to easily describe a correlation between an element and other elements. Spatially relative terms should be understood in terms of the directions shown in the drawings, including the different directions of components at the time of use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are schematic cross-sectional views showing a nitride furnace according to the present invention.

1 and 2, a nitriding furnace 1 according to the present invention includes an outcasing portion 10; A port 20 located inside the outcasing portion 10; And an enceasing portion 30 located inside the port 20. [

The outcasing unit 10 includes an outcasing 11 having an upper opening and a lid 12 for opening and closing an upper portion of the opened outcasing 11.

The port 20 is located inside the outcasing 11 and forms a space 21 with the outcasing 11.

The upper portion of the port 20 is opened and the upper portion of the opened port can be opened and closed by the lid of the outcasing portion 10.

The enchancing portion 30 includes an ingress 31 and a lid 12 which are open at upper and lower portions to communicate with the interior of the port 20 and accommodate the nitriding object 100 therein, And an auxiliary lid 32 for opening and closing the upper portion of the enceasing 31.

However, the present invention does not limit the presence or absence of the enqueasing unit 30.

On the other hand, the nitriding object 100 can be understood as a metal material for penetrating nitrogen to harden the surface, and it is preferable to maintain the cleaned state before the nitriding process.

It is understood that the nitriding object 100 is positioned inside the encasing 31 while being placed on the inner bottom surface of the port 20.

It should be understood that the nitriding object 100 is positioned inside the port 20 while being seated on the inner bottom surface of the port 20 when the ingelling portion 30 is excluded in the present invention .

1 and 2, the nitriding furnace 1 according to the present invention includes a circulating fan 13 positioned below the outcasing unit 10, A circulation fan 13a located inside the port 20 and a motor unit 13b located outside the outcasing unit 10 for driving the circulation fan 13a.

The nitrification furnace 1 according to the present invention includes a nitrogen gas supply unit 16 for supplying nitrogen to the port 20 and the nitrogen gas supply unit 16 has one end connected to the inside of the port 20 And a nitrogen gas supply control valve 16b for controlling the nitrogen supplied to the nitrogen gas supply pipe 16a.

The nitriding furnace 1 according to the present invention further includes a process gas supply unit 17 for supplying a process gas to the port 20 and one end of the process gas supply unit 16 is connected to the port 20 And a process gas supply control valve 17b for controlling the process gas supplied to the process gas supply pipe 17a.

At this time, nitrogen gas of N ₂ , N ₂ + CO ₂ may be supplied to the nitrogen gas supply unit 16, and gas such as NH ₃ may be supplied to the process gas supply unit 17.

Meanwhile, as shown in the drawing, one end of the nitrogen gas supply pipe 16a and one end of the process gas supply pipe 17a are preferably located below the circulation fan 13a, The nitrogen gas supplied through the nitrogen gas supply pipe 16a and the process gas supplied through the process gas supply pipe 17a can be easily circulated by the circulation fan 13a.

That is, the circulating fan unit 13 uniformly distributes the nitrogen gas and the process gas in the space 21 by the convection action, so that the contact with the nitrification object 100 can be performed smoothly do. Therefore, the surface hardness of the object to be nitrided can be expected to be improved.

Fig. 3 is a schematic bottom view showing a lid of a nitriding furnace according to the present invention, Fig. 4 is a schematic sectional view showing a lid of a nitriding furnace according to the present invention, Fig. 5 is a cross- 1 is a schematic view for explaining a flow.

3, the nitrided lid 12 according to the present invention includes a gas inflow portion 83 located on the lower surface of the lid 12 and located in an outer region of the lid 12, And a gas discharge portion 86 located on the lower surface of the lid 12 and located in the central region of the lid 12. [

The gas inlet 83 includes a plurality of gas inlets 81a and 81b and a gas inlet partition plate 82 for partitioning the plurality of gas inlets 81a and 81b.

The gas discharge portion 86 includes a plurality of gas discharge ports 84a and 84b and a gas discharge port partition 85 for partitioning the plurality of gas discharge ports 84a and 84b.

3, the gas inlet 83 is partitioned by the gas inlet partition plate 82 to form a plurality of gas inlet openings 81a and 81b, And is partitioned by the gas discharge port partition plate 85 to form a plurality of gas discharge ports 84a and 84b.

4 and 5, the gas introduced into the gas inlet 83 is circulated and discharged to the gas outlet 86. More specifically, the plurality of gas inlets 81a and 81b May be circulated and discharged to the plurality of gas outlets 84a and 84b.

As described above, in the present invention, the gas inlet portion 83 is located in the outer region of the lid 12, and the gas outlet portion 86 is located in the central region of the lid 12 4 and 5, the gas flows into the outer region of the lid 12 in which the gas inlet portion 83 is located, and the gas outlet portion 86 is located at the position To the central region of the lid 12.

That is, the nitriding method in the present invention can be defined as a lower gas injection system, a lower circulation fan arrangement system, and an upper lid arrangement system.

2, after the gas has risen upward along the outer region of the object to be nitrided 100, the object to be nitrided (also referred to as " 100, and the gas flows downward along the central region of the nitriding object 100. Such a circulation system allows the nitriding of the outer region and the central region of the nitriding object 100 to be uniform, The thickness deviation does not occur.

However, in the case of the upper gas injection system, the upper circulation fan arrangement system, and the upper lid arrangement system, which is contrary to the present invention, the circulation of the gas is not easy and the gas is circulated to the central region of the nitrification object 100 Therefore, the nitriding between the outer region and the central region of the nitriding object 100 is not uniform, and a thickness variation of the nitride layer occurs.

1 and 2, the nitrification furnace 1 according to the present invention may further include an opening / closing device 15 for opening / closing the lid 12. [

That is, the nitrification furnace 1 can open the lid 12 by operating the opening / closing device 15, and at the same time, the auxiliary lid 32 can be opened while the lid 12 is opened.

Accordingly, after the lid 12 and the auxiliary lid 32 are opened, the nitriding object 100 can be accommodated in the encasing 31 in the port 20.

Thereafter, when the nitrification object 100 is accommodated in the ingather 31, the auxiliary lid 32 and the lid 12 can be closed by operating the opening / closing device 15. [

The nitriding heat treatment procedure in the opening and closing apparatus 15 and the nitriding furnace 1 is obvious in the art, so a detailed description thereof will be omitted.

1 and 2, the nitriding furnace 1 according to the present invention further includes an air exhausting portion 40 for sucking air remaining in the port 20 before nitriding heat treatment operation and discharging the air to the outside .

The air exhaust unit 40 includes an exhaust pipe 41 whose one end passes through the out casing 11 and is connected to the port 20 and a vacuum pump 42 connected to the other end of the exhaust pipe 41, .

The vacuum pump 42 is generally driven by receiving power from the outside.

The air exhaust unit 40 drives the vacuum pump 42 to suck air remaining in the port 20 and discharge the air to the outside.

For example, the air vent 40 drives the vacuum pump 42 for about 10 minutes to 15 minutes to remove the air remaining in the port 20.

At this time, the air exhaust part 40 is operated while the auxiliary lid 32 is opened with the enchainment 31 opened, so that the air remaining in the port 20 and the ingressing part 31 is sucked And can be discharged to the outside.

Also, after the air remaining in the port 20 is removed from the nitrification furnace 1, the nitridation heat treatment may be started after the inside of the nitrification furnace 1 is filled with nitrogen at a predetermined pressure.

The air exhaust unit 40 may further include a release valve 43 for controlling removal of air remaining in the port 20 by the vacuum pump 42.

Accordingly, the port 20 maintains a vacuum state in which no air remains, thereby preventing oxidation of the heat treatment object 100 during heating.

1 and 2, the nitrification furnace 1 according to the present invention may further include a pressurized discharge portion 50 for keeping the pressure in the port 20 constant.

The pressure release part 50 includes a pressurized discharge pipe 51 having one end portion communicating with the port 20 through the lid 12 and a pressurized discharge pipe 51 connected to a certain region of the pressurized discharge pipe 51, And a discharge valve (52).

The pressure release valve 52 maintains a constant pressure in the port 20 and rapidly discharges undissolved gas generated in the port 20 to the outside.

In other words, since the pressure release valve 52 is required to prevent air infiltration into the port 20 during the nitriding heat treatment, the pressure in the port 20 is maintained constant from the initial stage to the end of the operation, Decomposition gas generated from the non-decomposed gas is quickly discharged to the outside to maintain the proper pressure.

Therefore, the nitriding furnace 1 can prevent the inflow of air into the port 20, as well as shorten the nitriding treatment time and the like for the nitriding object 100.

1 and 2, a nitriding furnace 1 according to the present invention includes a cooling unit 60 for cooling the nitrogen heated in the port 20 and supplying the cooled nitrogen to the port 20 .

The cooling unit 60 can cool the nitrogen heated during the heat treatment in the port 20 and re-supply the heated nitrogen to the port 20 so that the rapid cooling effect of the nitridation object 100 can be expected.

The cooling unit 60 includes a first cooling pipe 61 having one end portion communicating with the inside of the port 20 through the out casing 11 and a second cooling pipe 61 connected to the other end of the first cooling pipe 61 A heat exchanger 63 connected between both ends of the first cooling pipe 61 and one end connected to the vacuum blower 62 and the other end connected to the exhaust pipe 41 And a second cooling pipe (64) connected to communicate with the second cooling pipe (64).

The vacuum blower 62 has a general shape that is driven by receiving power from the outside and sucks nitrogen contained in the port 20 to cool the first cooling pipe 61, the heat exchanger 63, The second cooling pipe 64, and the port 20 to be sequentially circulated.

The heat exchanger 63 may be an air-cooled or water-cooled type, and the present invention does not limit the type of the heat exchanger.

The heat exchanger 63 may include a first heat exchanger 63a and a second heat exchanger 63b. However, the number of the heat exchangers 63 is not limited in the present invention.

The cooling unit 60 includes a first flow control valve 65 positioned between the heat exchanger 63 and the vacuum blower 62 and connected to the first cooling pipe 61, And a second flow control valve (66) connected between the second cooling pipe (64) and the exhaust pipe (41).

The first flow control valve 65 and the second flow control valve 66 control the amount of nitrogen re-flowing into the vacuum blower 62 and the port 20, respectively, And the like.

That is, in the nitriding furnace 1 according to the present invention, nitrogen heated in the port 20 is cooled while passing through the heat exchanger 63 as the vacuum blower 62 is driven, The rapid cooling effect of the nitridation object 100 can be expected.

In addition, since the nitrogen is circulated in the vacuum state, oxidation of the nitridation object 100 due to the inflow of air can be prevented.

1 and 2, the nitriding furnace 1 according to the present invention may further include an air supplying unit 70 for cooling the nitriding object 100 by supplying air from the outside .

The air supply unit 70 may include a cooling fan (not shown) for supplying outside air to the space 21 and may be connected to the cooling fan (not shown) A supply pipe 71, and a discharge pipe 72 for discharging the air supplied to the space 21 to the outside.

In the present invention, the supply pipe 71 is connected to the lower portion of the outer casing 11 to communicate with the space portion 21, and the discharge pipe 72 is connected to the space portion 21, (Not shown).

Therefore, in the present invention, the outside air is supplied to the lower side of the outcasing 11 and can be discharged to the upper side of the outcasing 11. In this process, the nitriding object 100 to be nitrided by heat treatment is cooled .

That is, in the nitriding furnace 1 according to the present invention, when the cooling fan (not shown) is driven to cool the nitriding object 100 subjected to the nitriding heat treatment in the ingelling portion 30, And flows into the space portion 21 from the lower side of the out casing 11. [

The air flowing into the space part (21) circulates along the space part (21) to cool the port (20) and the out casing (11).

Accordingly, the nitriding object 100 received in the ingot 30 is naturally cooled as the port 20 and the outer casing 11 are cooled, and the ports 20 and The air that has cooled the out casing portion 10 is discharged to the outside through the discharge pipe 72 connected to the upper portion of the out casing 11 in the state of the hot air absorbing heat.

As described above, the nitriding furnace (1) according to the present invention comprises an outcasing portion (10); A port 20 located inside the outcasing portion 10; And an enceasing portion 30 located inside the port 20. [

The outer casing unit 10 includes an outer casing 11 having an upper opening and a lid 12 for opening and closing an upper portion of the opened outer casing 11. The outer casing unit 10 And a circulation fan unit 14 located at a lower portion of the circulation fan unit 14.

The circulating fan unit 13 includes a circulation fan 13a located inside the port 20 and a motor unit 13 located outside the outcasing unit 10 for driving the circulation fan 13a, (13b).

The nitrification furnace 1 according to the present invention includes a nitrogen gas supply unit 16 for supplying nitrogen to the port 20 and the nitrogen gas supply unit 16 has one end connected to the inside of the port 20 And a process gas supply unit (17) for supplying a process gas to the port (20), wherein the process gas supply unit (16) has a gas supply pipe (16a) And a process gas supply pipe 17a located inside the process gas supply pipe 20.

At this time, it is preferable that one end of the nitrogen gas supply pipe 16a and one end of the process gas supply pipe 17a are located below the circulation fan 13a. Accordingly, in the present invention, the nitrogen gas supply pipe 16a And the process gas supplied through the process gas supply pipe 17a can be easily circulated by the circulation fan 13a.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (7)

Out casing unit;
A port located inside the out casing portion; And
And a circulation fan unit positioned below the out casing unit,
Wherein the outcasing portion includes an outcasing having an upper opening and a lid opening and closing an upper portion of the opened outcasing,
The lid,
A gas inlet located on a lower surface of the lid and located in an outer region of the lid; And a gas discharging portion located on a lower surface of the lid and located in a central region of the lid,
The gas introduced into the gas inlet portion is circulated and discharged to the gas outlet portion,
Wherein the gas flows into an outer region of the lid where the gas inlet is located and is discharged to a central region of the lid where the gas outlet is located. The method according to claim 1,
Further comprising an ingaking portion located inside the port,
Wherein the enceasing portion includes an enceasing portion having an upper portion and a lower portion opened and communicating with the inside of the port and containing an object to be nitrided inwardly and an auxiliary lid connected to the lid and opening and closing the upper portion of the enceasing portion,
Wherein the circulation fan unit includes a circulation fan located inside the port and a motor unit located outside the outflow casing to drive the circulation fan. 3. The method of claim 2,
A nitrogen gas supply unit for supplying nitrogen to the port; And
Further comprising a process gas supply unit for supplying a process gas to the port,
Wherein the nitrogen gas supply unit includes a nitrogen gas supply pipe having one end located inside the port and the process gas supply unit includes a process gas supply pipe having one end located inside the port,
Wherein one end of the nitrogen gas supply pipe and one end of the process gas supply pipe are located at a lower portion of the circulation fan. The method of claim 3,
The nitrification furnace further includes an air exhausting portion for sucking the air remaining in the port and discharging the air to the outside,
Wherein the air exhausting portion includes an exhaust pipe having one end portion communicating with the port through the out casing and a vacuum pump connected to the other end portion of the exhaust pipe,
The nitriding furnace further includes a cooling unit for cooling the heated nitrogen from the port and supplying the cooled nitrogen to the port,
Wherein the cooling section includes: a first cooling pipe, one end of which passes through the out casing and communicates with the inside of the port; A quadrature blower connected to the other end of the first cooling pipe; A heat exchanger connected between both ends of the first cooling pipe; And a second cooling pipe connected at one end to the vacuum blower and at the other end to communicate with the exhaust pipe. The method of claim 3,
N ₂ or N ₂ + CO ₂ gas is supplied to the nitrogen gas supply unit, and NH ₃ gas is supplied to the process gas supply unit. delete The method according to claim 1,
Wherein the gas inlet comprises a plurality of gas inlets and a gas inlet compartment defining the plurality of gas inlets,
Wherein the gas discharge portion includes a plurality of gas discharge ports and a gas discharge port partition for partitioning the plurality of gas discharge ports.

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