KR102326856B1 - Gas carburizing heat treatment apparatus in vacuum and heat treatment method using apparatus - Google Patents

Abstract

Provided are a gas carburizing heat treatment apparatus in a vacuum state and a heat treatment method using the same. The provided gas carburizing heat treatment apparatus comprises: a first heat treatment furnace which has a heat treatment space inside thereof and forms an end of one side in an outwardly convex shape to spread gas injected thereinto throughout the inside along an inner wall; a second heat treatment furnace which is formed in the same or the similar way with the first heat treatment furnace and is placed to face an opening part with the first heat treatment furnace; a blocking door which is placed between the first heat treatment furnace and the second heat treatment furnace and simultaneously seals the first heat treatment furnace and the second heat treatment furnace; and a moving unit which rotates and moves the first heat treatment furnace and the second heat treatment furnace. The gas carburizing heat treatment apparatus entirely injects gas and regularly heat-treats a surface of a heat treatment specimen.

Description

Gas carburizing heat treatment apparatus in a vacuum state and heat treatment method using the same

The present invention relates to a gas carburizing heat treatment apparatus in a vacuum state and a heat treatment method using the same.

In general, a vacuum gas carburizing heat treatment apparatus is an apparatus for heat-treating a workpiece by injecting gas after increasing the temperature in a vacuum state by depressurizing the inside. Vacuum heat treatment furnace has the advantage that there is no discoloration due to heat treatment, there is little deformation of the workpiece during cooling, and decarburization and carburization do not occur. Even with the same component, the structure of steel materials can vary greatly depending on the heat treatment method. That is, by appropriately heat-treating the steel material to change the mechanical properties and other properties of the steel material, it can be effectively used according to the intended use.

Among these steel materials, hot-form steel contains carbon (C), chromium (Cr), tungsten (W), silicon (Si), nickel (Ni), molybdenum (Mo), manganese (Mn), and vanadium (V) in iron. and alloy steel containing elements such as cobalt (Co). Hot-formed steel is mainly used as a molding material that requires mechanical strength properties at high processing temperatures. In order to be used for this purpose, hot-form steel is required to have sufficient strength, excellent hardness at high temperatures, and wear resistance. As one of the methods for improving the mechanical properties of hot-formed steel, a surface hardening technique using heat treatment is being developed.

The carburizing heat treatment method, which is a type of surface hardening method, forms a high-carbon alloy layer on the surface of the workpiece by injecting carbon into the surface layer of the workpiece made of low-carbon steel. In this regard, as a prior art, there is Republic of Korea Patent Registration No. 10-2162465 (registered on September 25, 2020). The prior art includes a support provided in the center of the housing for accommodating hot molded steel, a plurality of heating rods radially arranged on the inner wall of the housing, and a gas supply unit for injecting gas to flow along the support; To a vacuum carburizing heat treatment apparatus for hot-formed steel comprising a gas discharge unit for evacuating air and injected gas, and to a vacuum carburizing heat treatment method for hot-formed steel using the same.

However, since the vacuum carburizing heat treatment apparatus of the present prior art is not provided with a separate cooling device, it may take a long time until the heating rod is cooled by simply turning off the power of the heating rod that has been heated at a high temperature. In addition, even if the pedestal is configured in the form of a plurality of holes or meshes, there is a problem in that it is difficult to uniformly heat-treat the surface of the hot-formed steel that is in contact with the pedestal and is not covered by gas and heat uniformly.

Registered Patent No. 10-2162465 (Registered on September 25, 2020)

An object of the present invention is to provide a gas carburizing heat treatment apparatus in a vacuum state, and a heat treatment method using the same, in which gas is completely injected and the surface of a heat treatment specimen can be uniformly heat treated.

According to an aspect of the present invention, a first heat treatment furnace having a heat treatment space therein, one end of which is formed in a convex shape to the outside, so that the gas injected into the inside can be spread as a whole along the inner wall; and a second heat treatment furnace formed identically or similarly to the first heat treatment furnace and disposed to face the first heat treatment furnace and the opening; and disposed between the first heat treatment furnace and the second heat treatment furnace, the first heat treatment furnace and the first heat treatment furnace a blocking door capable of simultaneously sealing the heat treatment furnace and the second heat treatment furnace; and a moving unit capable of rotating and moving the first heat treatment furnace and the second heat treatment furnace.

The heat treatment apparatus according to the embodiments of the present invention is characterized in that the high temperature and low temperature heat treatment can be performed separately. Since it may take a long time for the heat treatment furnace to rise to a high temperature and then lower to a low temperature, the heat treatment process can be easily performed by separating the heat treatment furnaces of relatively high temperature and low temperature and performing the heat treatment. If necessary, by alternating the high-temperature and low-temperature heat treatment apparatus, the life of the heat treatment apparatus may be prolonged. In addition, in the heat treatment apparatus of the present invention, gas may be simultaneously injected and discharged as a whole through a plurality of input and discharge holes. In addition, since the heat treatment apparatus of the present invention can rotate the heat treatment furnace through the moving part, it is possible to heat the heat treatment specimen evenly as a whole by inverting the heat treatment specimen accommodated therein without opening the heat treatment furnace. In addition, the heat treatment method using the heat treatment apparatus of the present invention can effectively crack the surface of the heat treatment specimen through a two-step preheating process before performing the carburizing heat treatment, so that the gas can easily penetrate. In addition, even after the carburizing heat treatment is performed, the surface of the heat treatment specimen can be formed smoothly through reheat treatment and low temperature tempering.

1 is an internal cross-sectional view of a heat treatment apparatus according to an embodiment of the present invention.
FIG. 2 is a side cross-sectional view of the heat treatment apparatus shown in FIG. 1 .
FIG. 3 is an internal cross-sectional view illustrating the rotation of the heat treatment apparatus shown in FIG. 1 .
4 is an internal cross-sectional view illustrating a state in which the blocking door of the heat treatment apparatus shown in FIG. 1 is raised.
5 is a cross-sectional view illustrating the movement of a heat treatment specimen from the first heat treatment furnace shown in FIG. 1 to the second heat treatment furnace.
6 is a cross-sectional view illustrating a gas injection flow of the heat treatment apparatus shown in FIG. 1 .
7 is a cross-sectional view showing a gas exhaust flow of the heat treatment apparatus shown in FIG. 1 .
FIG. 8 is a cross-sectional view illustrating gas injection and exhaust flows of the heat treatment apparatus shown in FIG. 1 .
9 is a diagram illustrating a sequence of heat treatment of a heat treatment specimen using the heat treatment apparatus shown in FIG. 1 .
10 is a block diagram illustrating a sequence of heat-treating a heat treatment specimen using the heat treatment apparatus shown in FIG. 1 .

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be noted that the following examples are provided to help the understanding of the present invention, and the scope of the present invention is not limited to the following examples. The following embodiments are provided to more completely explain the present invention to those with average knowledge in the relevant technical field, and detailed descriptions for known configurations that may unnecessarily obscure the technical gist of the present invention to be omitted.

1 is an internal cross-sectional view of a heat treatment apparatus according to an embodiment of the present invention. FIG. 2 is a side cross-sectional view of the heat treatment apparatus shown in FIG. 1 . FIG. 3 is an internal cross-sectional view illustrating the rotation of the heat treatment apparatus shown in FIG. 1 . 4 is an internal cross-sectional view illustrating a state in which the blocking door of the heat treatment apparatus shown in FIG. 1 is raised. 5 is a cross-sectional view illustrating the movement of a heat treatment specimen from the first heat treatment furnace shown in FIG. 1 to the second heat treatment furnace.

1 to 5 , in the heat treatment apparatus 100 according to the present embodiment, a pair of heat treatment furnaces 110 and 140 may be symmetrically disposed to face each other with openings. The heat treatment specimen 10 may be introduced into the heat treatment apparatus 100 to perform heat treatment. For example, a relatively high temperature heat treatment may be performed in the first heat treatment furnace 110 , and a relatively low temperature heat treatment may be performed in the second heat treatment furnace 140 . After the inside of the heat treatment furnace is raised to a high temperature, it may take a long time until the temperature is lowered, so the heat treatment can be performed by dividing the high temperature and low temperature heat treatment furnace and moving the heat treatment specimen 10 to a heat treatment furnace suitable for the heat treatment cycle. have. In addition, the heat treatment furnaces 110 and 140 of the present embodiment are formed to be rotatable, so that the heat treatment specimen 10 can be uniformly heat treated as a whole by rotating the heat treatment furnace.

Specifically, the heat treatment apparatus 100 is a first heat treatment furnace 110 in which a high-temperature heat treatment is performed, a support unit 120 in which the heat treatment specimen 10 is accommodated on the upper side, and is disposed inside the heat treatment furnaces 110 and 140, A heat generating unit 130 for dissipating heat, a second heat treatment furnace 140 for performing low-temperature heat treatment, a blocking door 150 disposed between the first heat treatment furnace 110 and the second heat treatment furnace 140 , heat treatment It may include a moving unit 160 capable of rotating and moving the furnaces 110 and 140 and a support 170 disposed below the heat treatment furnaces 110 and 140 .

The first heat treatment furnace 110 may have a heat treatment space therein, and may have a dual structure of an outer cylinder 111 and an inner cylinder 112 . One end of the first heat treatment furnace 110 is formed to have an outwardly convex shape, so that the gas injected therein can be spread throughout the interior along the inner wall. That is, one end of the first heat treatment furnace 110 may be formed in an outwardly convex shape, and the other end may be formed in a hemispherical shape with an opening. Specifically, the first heat treatment furnace 110 includes an outer cylinder 111 through which gas is injected and discharged, an inner cylinder 112 disposed inside the outer cylinder and receiving a heat treatment specimen 10 therein, an outer cylinder 111 and an inner cylinder ( It may include a fixing pin 113 for fixing the 112 , a gas injection unit 114 and a gas discharge unit 115 disposed on the surface of the outer cylinder 111 .

The outer cylinder 111 is formed in a shape larger than that of the inner cylinder 112 , and gas may be injected and discharged through the gas injection unit 114 and the gas discharge unit 115 provided on the surface. The outer cylinder 111 may be formed in a hemispherical shape with one side convex outwardly and the other side open. A plurality of brackets are provided in the outer direction around the opening of the outer cylinder 111 so that the blocking door 150 to be described later can be fixed by a fastening member.

The inner cylinder 112 is formed in a shape smaller than the outer cylinder 111 by a predetermined degree, and may be disposed inside the outer cylinder 111 to be spaced apart from the outer cylinder 111 by a predetermined degree. A heat treatment specimen 10 may be disposed inside the inner cylinder 112 . More specifically, a support part 120 and a heating part 130 to be described later are disposed inside the inner cylinder 112 , and heat may be applied to the heat treatment specimen 10 accommodated in the upper side of the support part 120 . The support part 120 and the heating part 130 will be described in more detail later.

More specifically, a gas movement space 111a is formed between the outer cylinder 111 and the inner cylinder 112 , and the gas injected into the outer cylinder 111 may be accommodated in the gas movement space 111a. The gas accommodated in the gas movement space 111a may be introduced into the inner cylinder 112 through the input/discharge hole 112a provided on the surface of the inner cylinder 112 . Similarly, when the gas contained in the inner cylinder 112 is to be discharged, the gas is discharged to the gas movement space 111a through the input/discharge hole 112a, and the gas movement space 111a through the gas discharge unit 115. ) may be released.

The fixing pin 113 may be disposed between the outer cylinder 111 and the inner cylinder 112 to connect the outer cylinder 111 and the inner cylinder 112 . A plurality of fixing pins 113 may be disposed.

The gas injection part 114 is formed on the surface of the outer cylinder 111, and may be formed on the upper side and the lower side of the outer peripheral surface. Preferably, the gas injection unit 114 is disposed as a pair on the upper side and the lower side, so that gas can be easily injected even when the first heat treatment furnace 110 is rotated. In addition, the gas injection unit 114 is formed to be detachable from the gas cylinder, so that it is removed when the first heat treatment furnace 110 is rotated, and then reattached after rotation to easily release the gas even when the first heat treatment furnace 110 is rotated. injection is possible.

For example, the gas injection unit 114 may be used to inject a gas used in the heat treatment of the heat treatment specimen 10 or to inject a cooling gas that may be used in a cooling process after the heat treatment. That is, the gas injection unit 114 is formed to enable attachment and detachment of the gas cylinder, and in addition to the gas used during the heat treatment, a cooling gas is injected after the heat treatment, so that the heat treatment specimen 10 can be cooled more easily.

The gas discharge unit 115 is formed on the surface of the outer cylinder 111, it may be formed in a convex portion opposite to the opening. Preferably, the gas discharge part 115 is disposed on the convex part, so that the gas collected through the convex part can be easily discharged to the outside. Similarly, the gas discharge unit 115 is also formed to be detachable from the gas cylinder, so that it can be easily rotated by dropping it off when the first heat treatment furnace 110 is rotated.

Preferably, the gas injection unit 114 and the gas discharge unit 115 are formed to be sealable, so that the outer cylinder 111 can be sealed when not in use or in a situation where sealing is required.

6 is a cross-sectional view illustrating a gas injection flow of the heat treatment apparatus shown in FIG. 1 . 7 is a cross-sectional view showing a gas exhaust flow of the heat treatment apparatus shown in FIG. 1 . FIG. 8 is a cross-sectional view illustrating gas injection and exhaust flows of the heat treatment apparatus shown in FIG. 1 .

Referring to FIGS. 6 to 8 , the flow when the gas is injected and discharged into the heat treatment furnaces 110 and 140 will be described as follows.

6 to 7, when gas is injected and discharged into the heat treatment furnaces 110 and 140, respectively, through a plurality of input and discharge holes (112a) disposed on the outer peripheral surface of the inner cylinder (112) at the same time in several directions Gas can be injected and exhausted. That is, since the gas is injected and discharged from various directions, the gas can be evenly injected and discharged throughout the interior of the inner cylinder 112 . In this embodiment, since the gas is injected and discharged in a vacuum state inside the inner cylinder 112, when the gas is injected and discharged from one direction, in order to allow the gas to be injected and discharged to the entire inner cylinder 112, a predetermined It may take some time. Therefore, by allowing the gas to be simultaneously injected and discharged from several directions, the gas can be easily injected and discharged into the inner cylinder 112 in a short time.

In addition, referring to FIG. 8 , when the gas is injected and discharged into the heat treatment furnaces 110 and 140 at the same time, the gas injected by the convex shape of one side of the outer cylinder 111 and the inner cylinder 112 is applied to the inner wall surface. It can be induced to be discharged as it flows through the That is, the gas is introduced through the gas injection unit 114 disposed in the opening direction of the heat treatment furnaces 110 and 140, and the collected gas is discharged along the inner wall through the gas discharge unit 115 disposed in the convex portion direction. can be

On the other hand, the support part 120 is disposed inside the inner cylinder 112, the heat treatment specimen 10 may be accommodated in the upper side. Preferably, the support part 120 is formed with a plurality of holes or a mesh structure, so that gas and heat can be easily transferred to the heat treatment specimen 10 . In addition, the support part 120 may be disposed to face the inner upper and lower sides of the inner cylinder (112). The support part 120 is formed to be movable in the vertical direction, and may be moved in the vertical direction inside the inner cylinder 112 . Specifically, the pedestal 120 is connected to the pedestal 121 in which the heat treatment specimen 10 is accommodated on the upper side, the connecting part 122 connected to the lower side of the pedestal 121 and the connecting part 122 to connect the pedestal 121 . It may include a cylinder part 123 capable of moving in the vertical direction.

The pedestal 121 has a heat treatment specimen 10 capable of being seated on its upper side, and has a plurality of holes, so that heat and gas can be transferred to the heat treatment specimen 10 on the surface seated on the pedestal 121 . Alternatively, the pedestal 121 is formed in a mesh structure, so that heat and gas can be easily transferred to the heat treatment specimen 10 . For example, the pedestal 121 may be formed of a plate-shaped member, and both ends may be bent upward so that the heat treatment specimen 10 can be stably seated therein.

Alternatively, the pedestal 121 is provided with a plurality of rollers (not shown) to easily move the heat treatment specimen 10 accommodated on the upper side of the pedestal 121 from the pedestal 121 on one side to the pedestal 121 on the other side. can

The connection part 122 is connected to one side of the pedestal 121 , and may be formed to extend to the outside of the outer cylinder 111 . For example, one side of the connection part 122 is connected to the pedestal, and the other side is connected to the cylinder part 123 , so that the pedestal 121 can be moved up and down according to the operation of the cylinder part 123 . That is, the connection part 122 is formed to extend from the pedestal 121 disposed inside the first heat treatment furnace 110 to the outside of the first heat treatment furnace 110 , and is disposed outside the first heat treatment furnace 110 . It may be connected to the cylinder part 123 .

The cylinder part 123 may be connected to the connection part 122 to move the connection part 122 up and down. Preferably, the cylinder part 123 is arranged to be fixed to the outside of the outer cylinder 111 of the first heat treatment furnace 110 , and can be rotated when the first heat treatment furnace 110 rotates.

Meanwhile, the heat generating unit 130 may be disposed inside the inner cylinder 112 of the first heat treatment furnace 110 , and a plurality of heat generating units 130 may be disposed along the inner wall of the inner cylinder 112 . The heating part 130 may be disposed to be parallel to the support part 120 , and heat may be radiated toward the heat treatment specimen 10 accommodated in the upper side of the support part 120 . Specifically, the heating unit 130 may include a first heating unit 131 disposed at a position corresponding to the pedestal 121 and a second heating unit 132 disposed at a position where the pedestal 121 is not disposed. can

The first heating unit 131 may be disposed along the inner wall of the inner tube 112 , and may be disposed at a position corresponding to the pedestal 121 . In more detail, the first heat generating unit 131 is disposed on the rear side of the pedestal 121, and a plurality of the first heating units 131 may be disposed at relatively narrow intervals. The heat treatment specimen 10 accommodated on the upper side of the pedestal 121 is heat-treated because, even if a plurality of holes are formed in the pedestal 121 or formed in a mesh structure, a portion covered by the pedestal 121 is generated rather than a relatively open portion. may not be easily accomplished.

That is, the first heat generating part 131 is arranged at close intervals on the rear side of the pedestal 121, which is not relatively easily heat-treated, so that more heat is applied to the rear side of the pedestal 121 so that the gas is easily transferred to the pedestal 121 ) may be penetrated toward the heat treatment specimen 10 seated on the surface.

The second heat generating unit 132 may be disposed at a position where the pedestal 121 is not disposed, and may be disposed at a relatively wide interval compared to the first heat generating unit 131 . The second heat generating unit 132 is disposed along the inner wall of the inner tube 112, it may serve to increase the internal temperature of the inner tube (112).

The second heat treatment furnace 140 may be disposed to face the opening of the first heat treatment furnace 110 . That is, the opening of the second heat treatment furnace 140 and the opening of the first heat treatment furnace 110 are disposed to face each other, and the first heat treatment furnace 110 and the second heat treatment furnace ( 140) may be closed at the same time. In more detail, since the second heat treatment furnace 140 may be formed in the same or similar manner to the first heat treatment furnace 110 , a detailed description thereof will be omitted.

On the other hand, the blocking door 150 may be disposed between the first heat treatment furnace 110 and the second heat treatment furnace 140 to seal the first heat treatment furnace 110 and the second heat treatment furnace 140 at the same time. . The blocking door 150 may be sealed during heat treatment, and may be separated when moving the heat treatment specimen 10 . For example, the blocking door 150 may be lifted upward through a structure such as a hoist during separation. Specifically, the blocking door 150 includes a central blocking membrane 151 separating the first heat treatment furnace 110 and the second heat treatment furnace 140 , an inner cylinder blocking membrane 152 sealing the inner cylinder 112 , and a blocking door 150 . ) may include a moving ring 153 connected when the separation and a connection bracket 154 that can be fastened and fixed to the heat treatment furnaces 110 and 140 .

The center blocking film 151 may have the same or similar area as the opening of the outer cylinder 111 of the first heat treatment furnace 110 . The center blocking film 151 is disposed between the openings of the first heat treatment furnace 110 and the second heat treatment furnace 140 , and may be disposed to be spaced apart from each other by a predetermined degree. In addition, an extension portion connected to the periphery of the outer cylinder 111 is disposed on the periphery of the central blocking film 151 to be perpendicular to the central blocking film 151 , and may be fastened to the outer cylinder 111 .

The inner cylinder blocking film 152 is disposed on both sides of the central blocking film 151 , and may be disposed to be spaced apart from the central blocking film 151 by a predetermined degree. The inner cylinder blocking film 152 may have the same or similar area as the opening of the inner cylinder 112 . The inner cylinder blocking membrane 152 may be fixed while maintaining a predetermined distance from the center blocking membrane 151 by a fixing pin 113 . That is, the inner cylinder blocking film 152 and the center blocking film 151 are arranged to be spaced apart, and the gas movement space 111a between the outer cylinder 111 and the inner cylinder 112 is formed in a loop shape, so that the gas movement space 111a is formed. Allow the gas inside to circulate.

The movable ring 153 is formed around the center blocking film 151, and may be formed in an outward direction. The moving ring 153 may be disposed to be fixed to the lifting equipment when the blocking door 150 is separated and raised. For example, the moving ring 153 is formed on the outer periphery of the central blocking film 151, and is formed in a pair on the upper and lower sides, so as to easily separate the blocking door 150 even when the heat treatment furnaces 110 and 140 are rotated. can do it

More specifically, when a hoist (not shown) is provided on the upper side of the heat treatment apparatus 100, the movable ring 153 is formed in a ring shape, and the blocking door 150 is hung by hanging the movable ring 153 on the hook of the hoist. ) can be lifted. Alternatively, when a cylinder (not shown) is provided on the upper side of the heat treatment apparatus 100, the movable ring 153 is formed in a tongs-type shape that can be elastically operated inward, and is inserted into the ring provided in the cylinder to be fixed. can That is, the moving ring 153 is irrelevant as long as it can be fixed to a lifting device (not shown) for lifting the blocking door 150 , and is not limited to the illustrated shape.

The connection bracket 154 is disposed on an extension extending vertically on the periphery of the central blocking membrane 151 , and a plurality of connection brackets 154 may be disposed in an outward direction. The connection bracket 154 of the blocking door 150 may be fastened and fixed by a bracket and a fastening member provided around the opening of the outer cylinder 111 .

Meanwhile, the moving unit 160 may be respectively connected to the first heat treatment furnace 110 and the second heat treatment furnace 140 to rotate and move the heat treatment furnaces 110 and 140 . The moving unit 160 is erected in the form of a bar on the side surfaces of the first heat treatment furnace and the second heat treatment furnace 140 , and a rotating part 161, which will be described later, is formed to extend in the horizontal direction. It can be connected to one side. For example, when the heat treatment furnaces 110 and 140 are rotated to turn over the heat treatment specimen 10 accommodated in the heat treatment furnaces 110 and 140 , and the heat treatment specimen 10 is transferred from the first heat treatment furnace 110 to the second heat treatment furnace When moving to 140 , the heat treatment furnaces 110 and 140 may be rotated and moved by the moving unit 160 .

Specifically, the moving unit 160 may include a rotating unit 161 capable of rotating the heat treatment furnaces 110 and 140 and a left and right moving unit 162 capable of moving the heat treatment furnaces 110 and 140 .

The rotating unit 161 may rotate the first heat treatment furnace 110 and the second heat treatment furnace 140 about a rotation shaft 161a, which will be described later. The rotating unit 161 may extend in the horizontal direction to the moving unit 160 erected in the vertical direction on the ground, and may be connected to one side of the first heat treatment furnace 110 and the second heat treatment furnace 140 . The rotating unit 161 may include a rotating shaft 161a connected to the heat treatment furnaces 110 and 140 and a motor unit 161b capable of rotating the heat treatment furnaces 110 and 140 by rotating the rotating shaft 161a.

The left and right moving unit 162 is disposed at the lower end of the moving unit 160 to move the first heat treatment furnace 110 and the second heat treatment furnace 140 to the left and right. For example, the left and right moving unit 162 may move the moving unit 160 left and right by a lead screw or a cylinder formed on the bottom surface. When the moving unit 160 is moved left and right, the first heat treatment furnace 110 and the second heat treatment furnace 140 connected to the moving unit 160 may be moved left and right. Preferably, when the blocking door 150 is raised and the heat treatment specimen 10 accommodated in the first heat treatment furnace 110 is moved to the second heat treatment furnace 140 , the first heat treatment furnace 110 and the second heat treatment furnace The furnace 140 is in contact with each other, so that the heat treatment specimen 10 can be easily moved.

On the other hand, the support 170 is disposed below the first heat treatment furnace 110 and the second heat treatment furnace 140 , to support the rotation and movement of the first heat treatment furnace 110 and the second heat treatment furnace 140 . can Preferably, a plurality of supports 170 are provided so that they can be selectively lowered and raised during rotation and movement of the heat treatment furnaces 110 and 140 to be supported, respectively. In addition, the support 170 may be disposed as a pair to be spaced apart from the center by a predetermined degree so as not to interfere with the cylinder part 123 extending from the support part 120 to support the heat treatment furnaces 110 and 140 . Specifically, the support 170 may include a roller part 171 that is in contact with the movement and rotation of the heat treatment furnaces 110 and 140 and a cylinder part 172 that can adjust the height in the vertical direction of the support 170 . have.

The roller unit 171 may be disposed on the upper side of the support unit 170 to support the lower ends of the heat treatment furnaces 110 and 140 . The roller unit 171 includes a roller unit 171 that can be rotated in the y-axis direction to support it when the heat treatment furnaces 110 and 140 are rotated, and an x-axis to support it when the heat treatment furnaces 110 and 140 are moved. It may include a roller part 171 that can be rotated in the direction. The roller unit 171 prevents a large amount of friction from occurring between the support 170 and the heat treatment furnace 110 and 140 when the support 170 is supported in contact with the lower end of the heat treatment furnace 110 and 140 . It is disposed for, the heat treatment furnace (110, 140) while supporting the friction can be reduced.

The cylinder part 172 is disposed on one side of the support 170, so that the height can be adjusted in the vertical direction. For example, when rotating according to the operation of the heat treatment furnaces 110 and 140 , the support 170 on which the roller part 171 in the x-axis direction is disposed is placed on the cylinder part 172 so as not to contact the heat treatment furnaces 110 and 140 . can be lowered by Similarly, when the heat treatment furnaces 110 and 140 are moved, the support 170 on which the roller part 171 in the y-axis direction is disposed may be lowered by the cylinder part 172 . That is, according to the operation of the heat treatment furnaces 110 and 140, the support 170, which is required to be in contact, is raised by the cylinder part 172, and the support 170, which should not be in contact, may be lowered.

9 is a diagram illustrating a sequence of heat treatment of a heat treatment specimen using the heat treatment apparatus shown in FIG. 1 . 10 is a block diagram illustrating a sequence of heat-treating a heat treatment specimen using the heat treatment apparatus shown in FIG. 1 .

A process of heat-treating the heat treatment specimen 10, which is a hot-formed steel, using the heat treatment apparatus 100 of the present embodiment will be described with reference to FIGS. 9 to 10 .

로 조성하여 열처리 시편(10)을 1차 예열 처리할 수 있는 제2단계(S-2), 제1열처리로(110)의 내부에 질소 가스를 주입하고, 발열부(130)의 온도를 850 내지 870

로 조성하여 열처리 시편(10)을 2차 예열 처리할 수 있는 제3단계(S-3), 제1열처리로(110)의 내부의 질소 가스를 배기한 후, 탄화수소계 가스를 주입하고, 발열부(130)의 온도를 1050 내지 1070

로 조성하여 열처리 시편(10)을 가스 침탄 열처리할 수 있는 제4단계(S-4), 제1열처리로(110)의 내부의 탄화수소계 가스를 배기한 후, 질소 가스를 주입하고, 발열부(130)의 온도를 850 내지 870

로 조성하여 열처리 시편(10)을 재열처리할 수 있는 제5단계(S-5), 제1열처리로(110)에서 제2열처리로(140)로 열처리 시편(10)을 옮긴 후, 150 내지 170

로 조성된 제2열처리로(140)의 내부에서 열처리 시편(10)을 저온 템퍼링할 수 있는 제6단계(S-6) 및 상기 열처리 시편(10)을 상온까지 냉각시키는 제7단계(S-7)를 포함할 수 있다. First, in the first step (S-1) of seating the heat treatment specimen 10 on the pedestal 121 of the first heat treatment furnace 110, the inside of the first heat treatment furnace 110 is evacuated, and the heat generating unit 130 ) from 650 to 670

In the second step (S-2) in which the heat treatment specimen 10 can be first preheated by composition as to 870

In the third step (S-3) for secondary preheating of the heat treatment specimen 10 by composition of The temperature of the section 130 is 1050 to 1070

In the fourth step (S-4) in which the heat treatment specimen 10 can be gas-carburized heat treated by composition with 130 to 850 to 870 temperature

After transferring the heat treatment specimen 10 from the first heat treatment furnace 110 to the second heat treatment furnace 140 in the fifth step (S-5) in which the heat treatment specimen 10 can be reheat treated by composition as 170

A sixth step (S-6) capable of low-temperature tempering of the heat treatment specimen 10 in the interior of the second heat treatment furnace 140 composed of 7) may be included.

More specifically, the first preheating treatment step of the second step (S-2) may be performed for 30 minutes. As the first preheating treatment is performed, the surface structure of the heat treatment specimen 10 may start to crack. As such, since the surface structure of the heat treatment specimen 10 is cracked, the hydrocarbon-based gas can effectively react with the cracked surface structure in a carburizing heat treatment process to be described later. In addition, if the temperature of the heating rod is less than 650 ℃, cracking of the surface structure of the heat treatment specimen 10 may not be made well, and if it exceeds 670 ° C., the surface structure of the heat treatment specimen 10 is unevenly cracked and finally the heat treatment specimen (10) may have an effect on the quality.

Thereafter, the second preheating step of the third step S-3 may be performed for 120 minutes. _{In the second preheating step, nitrogen (N 2} ) gas, which is a dilution gas, may be injected to adjust the internal pressure of the first heat treatment furnace 110 that was in a vacuum state. Since the second preheating treatment is performed at a higher temperature than the first preheating treatment, the pressure may increase and affect the intrinsic properties of the heat treatment specimen 10, so nitrogen gas is injected to the pressure inside the first heat treatment furnace 110 This can be kept stable. After the second preheating treatment, the surface texture may be more finely cracked than during the first preheating treatment. In addition, if the temperature of the heating rod is less than 850 ° C., cracking of the surface structure of the heat treatment specimen 10 may not be made well, and when it exceeds 870 ° C. (10) may have an effect on the quality.

Thereafter, the carburizing heat treatment step of the fourth step (S-4) may be performed for 90 minutes. A carburizing layer may be formed in the first heat treatment furnace 110 in which the hydrocarbon-based gas is injected into the heat treatment specimen 10 in which the surface structure is cracked after the secondary preheating treatment. At the carburizing heat treatment temperature, the hydrocarbon-based gas is diffused and grown between the cracks on the surface of the heat treatment specimen 10 to form a carburizing layer on the surface of the heat treatment specimen 10 as the tissue is homogenized.

Thereafter, the reheat treatment step of the fifth step (S-5) may be performed for 120 minutes. After the carburizing heat treatment step, the heat treatment specimen 10 having a carburized layer formed on the surface thereof is reheat-treated at 850 to 870° C. to prevent a sudden drop in temperature to prevent cracks in the heat treatment specimen 10 . In the reheat treatment step, after exhausting all of the hydrocarbon-based gas injected into the first heat treatment furnace 110 , nitrogen gas is injected, the power of the heat generating unit 130 is turned off, and the temperature of the first heat treatment furnace 110 is lowered. After lowering to the reheat treatment temperature, it can be maintained.

For example, since it may take a long time for the temperature of the first heat treatment furnace 110 to drop, a cooling gas may be injected through the gas injection unit 114 to lower the temperature inside the first heat treatment furnace 110 . The reheat treatment step refines the surface of the assembled heat treatment specimen 10 according to long-term heating at high temperature, prevents the surface layer from becoming soft, and increases hardness. As described above, the surface structure of the heat-treated specimen 10 is transformed into martensite through cooling in a nitrogen atmosphere, so that the surface of the heat-treated specimen 10 can be effectively hardened.

Thereafter, the low-temperature tempering step of the sixth step (S-6) may be performed at about 150 to 170° C. for 180 minutes before cooling the heat-treated specimen 10 completed up to the re-heat treatment step to room temperature. The low-temperature tempering step reduces the residual stress remaining on the surface of the heat-treated specimen 10 to reduce the brittleness of the heat-treated specimen 10, and toughness is added to improve physical properties.

As described above, the heat treatment apparatus according to the embodiments of the present invention has a feature that can perform the high-temperature and low-temperature heat treatment separately. Since it may take a long time for the heat treatment furnace to rise to a high temperature and then lower to a low temperature, the heat treatment process can be easily performed by separating the heat treatment furnaces of relatively high temperature and low temperature and performing the heat treatment. If necessary, by alternating the high-temperature and low-temperature heat treatment apparatus, the life of the heat treatment apparatus may be prolonged.

In addition, in the heat treatment apparatus of the present invention, gas may be simultaneously injected and discharged as a whole through a plurality of input and discharge holes. A plurality of input and discharge holes that can be injected and discharged into the inner cylinder of the heat treatment furnace in which the heat treatment specimen is accommodated are provided on the surface of the inner cylinder, so that the gas injection and discharge can be simultaneously and easily injected and discharged as a whole. That is, since the injection and discharge of gas into the heat treatment specimen are uniformly and simultaneously performed, the depth of the gas uniformly penetrating into the surface of the heat treatment specimen can be made uniform.

In addition, since the heat treatment apparatus of the present invention can rotate the heat treatment furnace through the moving part, it is possible to heat the heat treatment specimen evenly as a whole by inverting the heat treatment specimen accommodated therein without opening the heat treatment furnace. The heat-treated specimen accommodated in the pedestal may transmit less heat and gas to the portion in contact with the pedestal than to the non-contact portion. Accordingly, since the gas may not uniformly permeate the surface of the heat-treated specimen, the heat-treated specimen is turned over during the heat treatment process, and the gas may penetrate the heat-treated specimen to a uniform depth as a whole.

In addition, the heat treatment method using the heat treatment apparatus of the present invention can effectively crack the surface of the heat treatment specimen through a two-step preheating process before performing the carburizing heat treatment, so that the gas can easily penetrate. In addition, even after the carburizing heat treatment is performed, the surface of the heat treatment specimen can be formed smoothly through reheat treatment and low temperature tempering. That is, the depth of the hydrocarbon-based gas penetrating into the heat treatment specimen may be increased, and since it has a smooth surface, the formability may be improved.

In the above, although embodiments of the present invention have been described, those of ordinary skill in the art can add, change, delete or add components within the scope that does not depart from the spirit of the present invention described in the claims. The present invention may be variously modified and changed by, etc., and this will also be included within the scope of the present invention.

10: heat treatment specimen 100: heat treatment device
110: first heat treatment furnace 111: outer cylinder
112: inner cylinder 113: fixing pin
114: gas injection unit 115: gas discharge unit
120: support 121: support
122: connection part 123: (support part) cylinder part
130: heating part 131: first heating part
132: second heating unit 140: second heat treatment furnace
150: blocking door 151: central blocking film
152: inner barrier barrier 153: moving ring
154: connection bracket
160: moving unit 161: rotating unit
162: left and right moving unit 170: support
171: roller portion 172: (support) cylinder portion

Claims (7)

a first heat treatment furnace 110 having a heat treatment space therein, one end of which is formed in a convex shape to the outside, so that the gas injected into the inside can be spread as a whole along the inner wall;
a second heat treatment furnace 140 formed to be the same as or similar to the first heat treatment furnace 110 , and disposed to face the opening of the first heat treatment furnace 110 ;
A blocking door 150 is disposed between the first heat treatment furnace 110 and the second heat treatment furnace 140 to seal the first heat treatment furnace 110 and the second heat treatment furnace 140 at the same time. ); and
and a moving unit 160 capable of rotating and moving the first heat treatment furnace 110 and the second heat treatment furnace 140 ,
The first heat treatment furnace 110,
an outer cylinder 111 through which gas can be injected and discharged; and
Doedoe provided inside the outer cylinder 111, the gas is simultaneously introduced and discharged through the input and discharge holes 112a arranged spaced apart from the outer cylinder 111 and arranged in a plurality on the upper, lower, left and right surfaces, respectively. Including the inner tube (112) that can be
The blocking door 150 is
a central blocking film 151 disposed at the center of the blocking door 150 and formed in the same or similar area as the outer cylinder 111 at a position corresponding to the opening of the outer cylinder 111; and
It is disposed on both sides of the central blocking film 151 and is formed in the same or similar area as the inner cylinder 112 at a position corresponding to the opening of the inner cylinder 112 to form a loop-type gas movement space 111a. Including, a gas carburizing heat treatment apparatus; delete The method according to claim 1,
The first heat treatment furnace 110,
Doedoe disposed inside the first heat treatment furnace 110, a support portion 120 in which the heat treatment specimen 10 can be accommodated on the upper side; and
Doedoe disposed inside the first heat treatment furnace 110, a plurality of pieces are disposed along the inner wall of the first heat treatment furnace 110, are disposed parallel to the support portion 120, the heat treatment specimen (10) Including, a gas carburizing heat treatment apparatus; The method according to claim 1,
The moving unit 160,
a rotating part 161 capable of rotating the first heat treatment furnace 110 and the second heat treatment furnace 140 about a rotary shaft 161a; and
A gas carburizing heat treatment apparatus including; 4. The method according to claim 3,
The heat generating unit 130,
Doedoe disposed at a position corresponding to the pedestal 121, a plurality of pieces arranged at relatively narrow intervals, a first heat generating unit 131 capable of dissipating heat with a strong intensity toward the heat treatment specimen 10; and
The pedestal 121 is disposed at a position where the pedestal 121 is not disposed, and a plurality of them are arranged at relatively wide intervals, and a second heat generating unit 132 capable of dissipating heat inside the first heat treatment furnace 110; Including, gas carburizing heat treatment apparatus. 4. The method according to claim 3,
The support part 120 is,
The heat treatment specimen 10 can be seated on the upper side, a plurality of holes are provided, the pedestal 121 through which heat and gas can be transmitted toward the heat treatment specimen 10;
a connection part 122 connected to one side of the pedestal 121 and extending to the outside of the first heat treatment furnace 110; and
Gas carburizing, including; disposed on the outside of the first heat treatment furnace 110, and connected to the end of the connection part 122, the cylinder part 123 capable of moving the support part 120 up and down heat treatment device. In the heat treatment method using the gas carburizing heat treatment apparatus of claim 1,
a first step (S-1) of seating the heat treatment specimen 10 on the pedestal 121 of the first heat treatment furnace 110;
A second step (S-) in which the inside of the first heat treatment furnace 110 is evacuated and the temperature of the heat generating unit 130 is set to 650 to 670° C. to preheat the heat treatment specimen 10 2);
A third step of injecting nitrogen gas into the first heat treatment furnace 110 and setting the temperature of the heat generating unit 130 to 850 to 870° C. to perform secondary preheating of the heat treatment specimen 10 (S-3);
After evacuating the nitrogen gas inside the first heat treatment furnace 110 , a hydrocarbon-based gas is injected, and the temperature of the heat generating unit 130 is set at 1050 to 1070° C. to gas-carburize the heat treatment specimen 10 . A fourth step (S-4) that can be heat treated;
After exhausting the hydrocarbon-based gas inside the first heat treatment furnace 110 , nitrogen gas is injected, and the temperature of the heat generating unit 130 is set at 850 to 870° C. to reheat the heat treatment specimen 10 . a fifth step that can be done (S-5);
After moving the heat treatment specimen 10 from the first heat treatment furnace 110 to the second heat treatment furnace 140, the heat treatment specimen ( 10) a sixth step (S-6) capable of low-temperature tempering; and
A heat treatment method using a gas carburizing heat treatment apparatus, characterized in that the gas carburizing heat treatment of the heat treatment specimen 10 is performed, including; a seventh step (S-7) of cooling the heat treatment specimen 10 to room temperature .

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