KR20080090058A - The hearth roll type continuity cementation heat treatment chamber - Google Patents

Abstract

A hearth roller type heat treatment furnace for performing continuous carbonization is provided to reduce loss time when a cycle is changed by adjusting the processing speed in heat treatment chambers according to the heat treatment conditions. A hearth roller type heat treatment furnace for performing continuous carbonization comprises a preheating chamber(10) for preheating a workpiece(100), a heat treatment chamber(20) for carbonizing the workpiece, a first hardening chamber(30) for hardening the workpiece, and a second hardening chamber(40) for protecting the hearth roller type heat treatment furnace from external air. The chambers are partitioned from each other by first to third partitions(15,25,35). A hearth roller unit(60) is provided to convey the workpiece.

Description

Hearth Roll type continuity cementation heat treatment chamber

1 is a view illustrating a configuration state of a conventional Haw roller continuous carburization heat treatment furnace.

2 is an exemplary configuration state of the present invention.

Figure 3 is an illustration of the configuration state that is the main part of the present invention.

4 is an exemplary embodiment of the present invention.

<Explanation of symbols for each major part of drawing>

10: Preheating room. 11: entrance door. 14: gas burner.

15: First partition. 16: Circulation fan.

20: heat treatment chamber. 21: Carburizing chamber. 22: diffusion chamber.

24: Electric Heater. 25: The second partition.

26: Circulation fan.

30: 1 hardening room. 34: Electric heater. 35: Third partition.

36: Circulation fan.

40: 2 hardening rooms. 41: Exit door. 44: Electric heater.

46: Circulation fan.

50: Fresh milk bath . 51: cylinder. 56: stirrer.

60: Haas roller. 65: drive motor.

70: O2 sensor. 80: treatment material loading device. 90: processing material taking out device.

100: processed material. 101: tray.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hearth roller type continuous carburizing furnace for industrial use, comprising: a preheating chamber for preheating the treated material, a heat treating chamber for carburizing and diffusing the preheated processed material, and a carburizing treatment in the heat treatment chamber. It consists of one quenching chamber for hardening water and two quenching chambers to protect the atmosphere, and the Hearth roller of the preheating chamber, heat treatment chamber, quenching chamber, and quenching chamber is separated by forward and reverse directions. It can be configured to drive separately, and to control the progress speed of the processed materials according to the heat treatment specifications, and at the same time, the atmosphere, cycle time, temperature, etc. of each of four chambers can be controlled separately, minimizing the disturbance of atmospheric gas. The purpose is to obtain a better quality product by uniformly carburizing and uniformly treating the tissue.

A major contribution to the development of human civilization is the discovery of metals and the use of them as various tools.

Therefore, all human beings have developed and developed technologies to handle metals, the most important of which is the heat treatment process that deals with the properties of metals. In performing such a heat treatment method, the treated material to be heat-treated is heated to obtain a desired property so that the structure of the metal is recrystallized. At this time, various components are penetrated into the metal structure to obtain the desired structure. It consists of a process of hardening, quenching, or annealing so that a tissue is formed appropriately for use.

In order to obtain a higher quality treatment in this heat treatment process, the heat treatment chamber that infiltrates other components such as carbon gas into the metal structure and the temperature of the martensite transformation (free diffusion transformation) and the quenching agent in the cooling process of the heat treatment treatment There is an Osttempering transformation (diffusion transformation) that takes a long time to complete the transformation.

In addition, the isothermal annealing technique is also used for heat treatment of treated materials. Instead of being cooled slowly in the furnace to ensure proper workability of the steel, it is quenched at a constant temperature (from the A1 transformation point to the nose part of the S curve) and then It is a technology to maintain temperature for a certain time. This isothermal transformation technique is used in that a uniform quality can be obtained than a continuous cooling method of only quenching to a certain temperature.

In particular, in the case of ostempering, the quality is stable, and there is a characteristic that it is possible to make an unusual tissue that is difficult to obtain in continuous cooling called bainite. This bainite is a kind of fine pearlite, which does not cause lattice distortion such as martensite transformation, so that its hardness is comparable with that of martensite, and its use is increasing. This bainite is divided into upper bainite obtained by transformation above 350 ° C and lower bainite obtained below.

The upper bainite is used for parts that require elasticity due to its excellent spring property (clips, spring washers, snap rings, etc.), while the lower bainite has high hardness while maintaining the spring property. Often used for parts.

In all such heat treatments, the process of maintaining the state as a means for heating the treated material to a constant temperature to form a perfect recrystallized structure is very important.

Therefore, the conveyor roller which is installed inside the heat treatment furnace due to the high temperature inside the heat treatment furnace is configured to move the treatment product according to the heat treatment state of the treatment product without being deformed at a high temperature and to be placed inside the furnace. It will play an important role. In other words, the rollers constituting the heat treatment furnace were divided into a preheating chamber, a heat treatment chamber, a quenching chamber, and a quenching chamber, and the rollers installed therein were simultaneously rotated by a single motor. As all the processes were performed, they could not be adapted to the size of the treatment and the atmosphere deformation inside the furnace, which caused the failure.

It is developed here and consists of three chambers (Chamber-preheating chamber, heat treatment chamber, crack chamber), and each chamber is divided into two doors, and there are three groups of independent hearth rollers. If there is water, the rollers of the preheating chamber and the crack chamber rotate forward and reverse, and the rollers of the heat treatment chamber are configured to maintain a stationary state or to rotate only forwardly, and the hearth roller is placed in a superheat resistant steel with a small amount of tungsten or cobalt ( Cobalt) and titanium are added. The side wall of the furnace body is formed from the inside of the furnace with a brick layer (fireproof), a silica layer (insulation material), a compression molding layer of titanium oxide and inorganic fiber (Fiber). Although there was a Japanese Patent Application No. 2002-348639, which was configured, there was also a deformation such as deflection of the roller due to high temperature due to the inconsistency between the waiting time and the advancing time in order to meet the individual conditions of each thread. In addition, regardless of the size of the tray containing the treatment, there is a lot of problems in controlling the time to stay inside by heat treatment of the treatment because the whole roller moves at a constant speed while rotating at the same time, in particular, heating the treatment to the recrystallization temperature As a result of many problems in performing a heat treatment step of performing a heat treatment process that infiltrates new components and a quenching step of transforming a structure by transforming a tissue while maintaining the heat treated treatment material at a transformation temperature, control of the feed rate of the furnace treatment is difficult. There have been many examples of failure to obtain a processed material of the desired quality due to prolonged loss time during cycle change.

The present invention has been made in view of the above problems, and relates to a low roller continuous carburizing heat treatment furnace for industrial use in constructing a low roller continuous carburizing heat treatment furnace for industrial use. A preheating chamber for preheating the treated material, a heat treatment chamber for carburizing and diffusing the preheated product, a quenching chamber for hardening the carburized material in the heat treatment chamber, and a quenching for atmosphere protection 2 Configure the chamber and individually drive the Hearth rollers of the preheating chamber, the heat treatment chamber, the quenching chamber and the quenching chamber in the forward and reverse directions by independent motors to control the running speed of each chamber according to the heat treatment condition. At the same time, the atmosphere, cycle time, temperature, etc. of each of the four chambers can be clearly distinguished, thereby causing the disturbance of the atmospheric gas occurring at this time. The minimized by picking a carburizing condition of water treatment consists of different tissues was uniformly so as to obtain the products so as to obtain a better quality of the product.

Looking at the technical configuration of the present invention described above are as follows.

2 and 3, in the present invention, a preheating chamber 10 for preheating the treated material 100 to be heat treated, a heat treatment chamber 20 for carburizing and diffusing the preheated processed material 100, These four chambers comprise one quenching chamber 30 for hardening and hardening the treated material 100 carburized in the heat treatment chamber 20 and two quenching chambers 40 for protecting the furnace atmosphere from outside air. Are divided into first, second, and third partition doors (15, 25, 35), respectively, and the atmosphere, cycle time, temperature, etc. of each chamber can be separately controlled. It is configured to individually drive the Hearth roller 60 for transport in the forward and reverse directions by independent driving motors 65 so as to control the traveling speed of each treatment according to the heat treatment specifications of the treatment 100. At the same time, by minimizing the disturbance of the atmosphere gas, the carburized state of the treated material 100 is uniform and the phase of the tissue is uniform To work.

Here, the preheating chamber 10 has an enclosed space with an entrance door 11 for blocking the charging entrance for charging the processing material 100 from the outside and a first partition door 15 partitioned from the heat treatment chamber 20. The refractory insulation material inside the furnace is formed of bricks, and the lower roller 60 for conveying the processed material 100 is configured to be preheated, but the lower roller 60 is all driven motors independently of each other. By 65, it is comprised so that forward and reverse rotation may be performed separately. And inside the upper side, the circulation fan 16 which makes the furnace temperature and furnace gas atmosphere uniform, and the atmosphere gas discharge port for discharging the furnace atmosphere gas are comprised.

Next, a heat treatment chamber in which the preheated treatment 100 is heated to the carburizing temperature and the gas of a component that changes the properties of the metal is introduced into the room to penetrate other components into the surface layer of the treatment 100. 20 is composed of a carburizing chamber 21 and a diffusion chamber 22 comprising two zones and a first partition door 12 partitioned from the preheating chamber 10 and a carburizing chamber 21 from the side. The diffusion chamber 22 is configured to communicate with each other to form a closed space of the second partition door 25 partitioned from the quenching chamber 1. And the inside constitutes a heat transfer heater 24 for heating the internal temperature and at the bottom constitute a hearth roller 60 for transporting the processing material 100, the hearth roller 60 is all of the independent drive motor By 65, it is comprised so that forward and reverse rotation may be performed separately. In addition, the inside of the heat treatment chamber 20 has a circulation fan 26 forcing convection of the atmosphere gas for uniform distribution of the atmosphere gas and the atmosphere gas inside the heat treatment chamber 20, and a partial pressure of O2 to minimize the amount of retained austenite and improve the carburizing depth. As a measurement equipment using the principle of electromotive force by the carburizing chamber 21, an O2 sensor 70 for measuring and controlling the atmosphere in the furnace by measuring the difference in electromotive force of O2 among reference air and atmospheric gas supplied into the furnace And are formed in the diffusion chamber 22, respectively.

The quenching one chamber 30 for transforming the properties of the processed material 100 heat-treated in the heat treatment chamber 20 is installed between the heat treatment chamber 20 and the quenching two chamber 40 and the heat treatment chamber 20 and Is partitioned into a second partition door 25 and the quenching chamber 2 and a third partition door 35 to form an independent chamber, where the quenching chamber 1 is configured to maintain a temperature-fall state. An electric heater 34 is configured, and a lower roller 60 for transporting the processing material 100 is formed at the bottom thereof, and the lower roller 60 is rotated forward and reverse individually by an independent drive motor 65. And inside the quenching chamber 1, the circulating fan 36 and the amount of retained austenite are forced to minimize the amount of retained austenite and the carburizing depth. Lepron as a measuring device using the principle of electromotive force by partial pressure The O2 sensor 70 is installed to measure and control the atmosphere in the furnace by measuring the difference in electromotive force of O2 among the reference air and the atmosphere gas supplied in the furnace.

The quenched two chamber 40, which is divided into the quenched one chamber 30 and the third partition door 35 and forms a space sealed by the exit door 41, has a heat-treated processed material 100 at a transformation temperature. To configure the heat transfer heater 44 for maintaining the temperature in the state of 830 ~ 860 ℃, at the bottom of the lower roller 60 for transporting the treated water 100, but the lower roller 60 is all Each is configured to rotate forward and reverse individually by an independent drive motor (65). In addition, the inside of the quenching chamber 2 constitutes a circulation fan 46 for forcing convection so that the heat and the atmosphere gas inside the quenching chamber 2 are evenly spread.

Here, the hearth roller is filled with fire-resistant insulation on both shafts inside the tube centrifugally cast into a heat-resistant casting steel to which a trace amount of tungsten is added, and a shaft is attached to both ends thereof to support the bearing from the outside of the furnace geared motor. It is driven by the inverter and the position control by the photosensor.

In addition, the entrance door 11 and the exit door 41 are constructed with a silica board and a brick inside, and configured to operate along a guide angle by an external driving device. The third partition doors 15, 25 and 35 are constructed of a heat-resistant casting steel material and constitute a connecting link and a roller guide.

In addition, the entrance door 11 and the exit door 41 are provided with a curtain burner (Curtain burner) in the lower portion to block the outside air to protect the atmosphere in the furnace when opening and closing.

In the present invention configured as described above, as shown in FIG. 4, a preheating chamber is provided in front of the preheating chamber 10 to be heat treated by installing an existing processing material loading device 80 to match the entrance door 11. (10) a stirrer configured to be introduced into the inside and quenching bath 50 for quenching by immersing in a salt or salt bath in the back of the quenching two chambers 40 and quenching water of the quenching bath 50 56 and a cylinder 51 having the processing material 100 immersed in the squeezing bath 50 and then taken out, and a processing material taking-out device 90 is installed at the rear thereof to complete the heat treatment. Install to pull outward.

Referring to the embodiment of the heat treatment facility 100 by performing the present invention installed as described above to complete the heat treatment simply described, first to open the entrance door 11 of the preheating chamber 10 to be heat treated (100) ) Is filled into the tray 101 into the preheating chamber 10 by using the treatment material loading device 80 and heated to 890 ~ 910 ℃. At this time, the hearth roller 60 of the preheating chamber 10 has the tray 101 containing the processing material 100 positioned inside the preheating chamber 10 while being reversed and driven separately by the independent driving motor 65. The circulation fan 16 installed on the upper side is driven to spread the internal temperature evenly. As described above, the processed material 100 heated to 890 to 910 ° C. in the preheating chamber 10 is heat treated by driving the Haas roller 14 which is individually driven by the independent driving motors while the first partition door 12 is opened. The carburizing chamber 21 of the chamber 20 enters.

The treated material 100 entering the carburizing chamber 21 of the heat treatment chamber 20 is heated to 910 to 920 ° C. by the heating of the heat transfer heater 24, and at this time, the carburizing gas is purged so that carburizing is performed on the processed material 100. The lower roller 60 which is driven forward and backward by the independent driving motors 65 of the heat treatment chamber 20 is driven in the forward and reverse directions while the carburizing chamber 100 is completely carburized. 21, and the circulation fan 26 installed above the carburizing chamber 21 is driven to promote diffusion of the carburized gas purged in the carburizing chamber 21. As described above, when carburizing is completed in the carburizing chamber 21, the processed material 100 moves to the diffusion chamber 22 by the driving of the individually driven hearth roller 60, and the continuous carburizing is performed by the diffused atmospheric gas. As a result, a plurality of trays 101 containing the processed material 100 are sequentially loaded in the internal space of the heat treatment chamber 20, and new physical properties such as carburization are added to the processed material 100.

The processed material 100 in which the heat treatment is completed in the above-described state is individually performed one by one in order by the lower roller 60 separately driven by the independent drive motor 65 while the second partition door 25 is opened. The quenching chamber 1 is discharged into the quenching chamber 30, in which the quenching chamber 2 has the effect of suppressing the disturbance of the inside of the heat treatment chamber 20 as much as possible to achieve more stable carburization.

When the second partition door 25 is closed in the above state and the heat treatment chamber 20 and the quenching chamber 1 are blocked, the treated material 100 discharged to the quenching chamber 1 has a temperature of 830 to 860 ° C. The third partition door 35 is opened while being formed in a new structure by moving away, and is moved to the hardening chamber 2 by the lower roller 60 separately driven by the independent driving motor 65. At this time, the circulation fan 36 of the quenching chamber 1 is driven to promote diffusion of the atmosphere of the quenching chamber 1.

The O2 sensor 70 installed therein while the processed material 100 passes through the heat treatment chamber 20 and the quenching chamber 1 30 is formed by partial pressure of O2 to minimize the amount of retained austenite and improve the carburizing depth. As a measuring equipment using the principle of electromotive force, the atmosphere in the furnace is measured and controlled by measuring the difference in electromotive force between O2 among reference air and atmospheric gas supplied into the furnace.

The processed material 100 entered into the quenching chamber 1 by the above method is to maintain a transformation temperature of 830 to 860 ° C. in the quenching chamber 1 to form a new structure. 30) The internal hearth roller 60 also rotates forward and reverse individually by independent driving motors 65, so that the processed material 100 remains effectively inside the hardened chamber 1 to form a stable structure. Will be.

In the above state, when the temperature lowering operation for completing the new structure of the processed material 100 is completed, the temporary stay in the hardening 2 chamber 40 is opened for a while and the exit door 41 is opened. 100) is rapidly quenched to about 200 ℃ in the simmering bath 50 configured to shower or soak with oil or salt. At this time, in the style immersed in the simmering bath 50, the cylinder 51 is operated to immerse the processed material 100 discharged from the heat treatment chamber 20 into the squeezing bath 50 and then lift out. The stirrer 56 of 50 is operated to vortex the cooling water so that the cooling water cools the processed material 100 at an even temperature.

In this way, if the processed material 100 quenched in the squeezing bath 50 is pulled out to the processing material taking out device 90, the heat treatment operation is completed.

As described above, the present invention comprises a quenching chamber between two quenching chambers in order to harden the carburized material in the heat treatment chamber in the Haas roller continuous carburizing heat treatment furnace. , Hrush roller of quenching 1 chamber and quenching 2 chamber are individually driven in the forward and reverse directions by independent driving motors, and the running speed of each chamber is adjusted according to the heat treatment specifications to reduce the loss time when the cycle is changed. Unlike conventional PUSHER method, it does not need to insert empty tray, and the atmosphere, cycle, and temperature of each four chambers can be controlled separately, and the carburizing condition of the treatment is even and the tissue is minimized by minimizing the disturbance of atmospheric gas. It is a novel and useful invention that the phases are uniform to obtain a better product.

Claims (7)

In constructing the hearth roller continuous carburizing furnace, The preheating chamber 10 for preheating the treated material 100 to be heat treated, the heat treated chamber 20 for carburizing and diffusing the preheated processed material 100, and the treated material 100 carburized in the heat treated chamber 20. A quenching chamber (30) for hardening and quenching, and a quenching chamber (40) for protecting the furnace atmosphere from outside air. 3 partition door 15, 25, 35 and the exit door 41 divided into four chambers (Chamber), Hearth roller continuous carburizing heat treatment furnace (爐), characterized in that configured to drive each of the Hath roller (Hearth roller) 60 for the transport of the processing material 100 in the forward and reverse directions by an independent drive motor (65) . The method of claim 1, The preheating chamber 10, the refractory heat insulating material in the furnace using a brick (brick), and constitutes a lower roller 60 for conveying the processed material 100, the upper inside the furnace uniform in the furnace temperature and atmosphere in the furnace Haas roller continuous carburizing heat treatment furnace characterized in that it comprises a circulating fan 16 and an atmosphere gas outlet 17 for discharging the atmosphere gas. The method of claim 1, The heat treatment chamber 20 is composed of two zones communicating with the carburizing chamber 21 and the diffusion chamber 22, and includes a heat transfer heater 24 for heating an internal temperature, and a processed material 100. Hearth roller 60 for conveying, circulation fan 26 for forced convection of atmospheric gas to uniformize the furnace temperature and the atmosphere in the furnace, and partial pressure of O2 to minimize the amount of retained austenite and control the carburizing depth. Haas roller continuous carburizing heat treatment furnace characterized in that for configuring the O2 sensor 70 to measure and control the atmosphere in the furnace by measuring the electromotive force difference of the O2 of the atmosphere gas supplied by the principle of electromotive force by. The method of claim 1, The quenching one chamber 30 is installed between the heat treatment chamber 20 and the quenching two chambers 40 and partitioned from the heat treatment chamber 20 to the second partition door 25 and with the quenching two chambers 40. The third partition door 35 is configured to constitute an independent chamber, the heat transfer heater 34 for maintaining the temperature-fall state, the lower roller 60 for transporting the processed material 100, the furnace temperature and the atmosphere inside the furnace. Difference of electromotive force of O2 among atmospheric gases supplied on the principle of electromotive force by partial pressure of O2 to minimize residual austenite and improve carburizing depth in order to force convection in the furnace atmosphere The O2 sensor 70 is installed to measure and control the atmosphere in the furnace, and the atmosphere of the heat treatment chamber 20 is disturbed when the heat treated material 100 is transferred from the heat treatment chamber 20 to the quenching one chamber 30. Hasler roller characterized in that the hardened 2 chamber 40 is configured to minimize A carburizing heat treatment (爐). The method of claim 1, The hearth roller is filled with a refractory insulating material inside the tube of centrifugally cast heat-resistant casting steel containing a very small amount of tungsten, and is attached to a shaft at both ends thereof to be supported by a bearing from the outside of the furnace body by a geared motor and an inverter. Haas roller continuous carburizing heat treatment furnace characterized in that the drive is configured to be controlled by the photosensor. The method of claim 1, The entrance door 11 and the exit door 41 are constructed with a silica board and a brick inside, and configured to operate along the guide angle by an external driving device, and a curtain burner at the bottom thereof. Curtain burner) is a Haas roller continuous carburizing heat treatment furnace characterized in that configured to block the outside air. The method of claim 1, The first, second and third partition doors (15) (25) (35) is constructed of a heat-resistant casting steel material, characterized in that consisting of a connecting link, roller guide Haas roller continuous carburizing heat treatment furnace (爐).

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