KR100315358B1 - A serial type of gas carburization furnace - Google Patents

Abstract

The present invention relates to a continuous gas carburizing device capable of minimizing generation of grain boundary oxide layers on a surface of a product and preventing degradation of product quality and durability, and the continuous gas carburizing device according to the present invention provides air in a carrying room. First inert and RX gas inlet tubes for injecting inert and RX gas to discharge, first air outlet tubes communicating with the inlet chamber for discharging air following inertness into the loading chamber and injection of RX gas, and quenching the carburized product A discharge chamber located between the carburizing zone and the scavenging tank for carrying out into the tank, a second inert and RX gas injection tube for injecting inert and RX gas to discharge air in the discharge chamber, and inert and RX gas injection into the discharge chamber. And a second air discharge pipe connected to the discharge chamber to discharge the air accordingly.

Description

A serial type of gas carburization furnace

The present invention relates to a continuous gas carburizing furnace, and more particularly to a continuous gas carburizing furnace having an air mixing prevention chamber and an air mixing prevention system in the inlet and outlet doors of the carburizing furnace.

Generally, carburization is a method of infiltrating and employing carbon into the surface layer of steel in order to increase the carbon content of steel, and is a surface hardening method for converting the surface portion of soft iron having a low carbon concentration to martensite having a high carbon concentration. For example, carburized steel is used for hard-to-wear and hard-to-part parts such as gears. Quenching after carburizing makes the surface harder and wear-resistant. In addition, since the center part is strong and has high impact resistance, it is machined in bearings, piston rings, and sliding parts of mechanical parts. Carburizing includes solid carburizing, liquid carburizing and gas carburizing.

FIG. 1 shows a conventional continuous gas carburizing apparatus, and the continuous gas carburizing apparatus includes a loading chamber 101, a preheating region 102, a carburizing region 103, a diffusion region 104, and a temperature lowering region 105. , Crack region 106 and quenching tank 107.

When the carrying room 101 is a so-called inlet chamber and the door 108 of the carrying room 101 is opened, the tray on which the material to be carburized is loaded is carried into the carrying room 101. The tray brought into the carrying room 101 is transferred to the preheating area 102 by the opening of the inner door 109 which opens and closes the communication between the carrying room 101 and the preheating area 102, and then the inner door 109. Is closed.

The material to be carburized is heated to a temperature of approximately 800 ° C. to 900 ° C. in the preheating region 102 and then transferred to the carburizing region 103. The material to be carburized is carburized so that carbon (C) penetrates into the surface of the product while the carburizing region 103 is maintained at the temperature as described above. The carburized material in the carburized region 103 is transferred to the expanded region 104 so that the product in which carbon has penetrated the surface of the product is treated to expand the carbon to the inside of the product while passing through the expanded region 104.

The product whose carbon is expanded to the inside is transferred to the temperature lowering region 105 by the opening of the door 110, and the product is cooled to a predetermined temperature to quench the product at the temperature lowering region 105, and thus the cracking region by the opening of the door 111. Transferred to 106, the temperature distribution is kept uniform, whereby the quality of the product can be made uniform. The product whose cracking is completed regularly is carried out with the opening of the door 112, is transferred to the sintering tank 107, and then quenched in the sintering tank 107.

However, in the conventional continuous gas carburizing apparatus having the structure as described above, when the material to be carburized from the loading chamber is transferred to the preheating region, air mixed in the interior of the loading chamber is mixed into the preheating region, thereby preheating and carburizing. And the atmosphere gas in the diffusion region becomes stable, while when the product is taken out from the crack region, air may enter the crack region due to the opening of the door 112, resulting in an unstable atmosphere state inside the apparatus.

The incorporation of air into the device combines with and oxidizes alloying elements (Mn, Si, Cr, etc.) on the metal surface as the amount of oxygen increases, thereby reducing the durability and quality of the product on the surface of the product, between the metal structures. The formation of the grain boundary oxide layer is promoted, and when the oxygen (O ₂ ) is large in the atmosphere gas, the grain boundary oxide layer is deep and large. This grain boundary oxide layer is dependent on the atmospheric gas state inside the apparatus.

Accordingly, an object of the present invention is to provide a continuous gas carburizing apparatus that can minimize the generation of grain boundary oxide layer on the surface of the product, and can prevent degradation of the quality and durability of the product.

1 is a view schematically showing the structure of a conventional continuous gas carburizing device.

Figure 2 schematically shows a continuous gas carburizing device according to the present invention.

(Explanation of symbols for the main parts of the drawing)

1: continuous gas carburizing device 2: carrying room

3: first inert and RX gas injection pipe 4: first air discharge pipe

5 ,: 14 check valve 6, 7, 15: door

8: preheating area 9: hardening tank

10: carburizing area 11: unloading room

12 second inert and RX gas inlet tube 13 second air outlet tube

16: valve

The object as described above includes an entry chamber into which a product is brought in, a carburizing zone for preheating a product transferred from the carrying room to a temperature, carburizing and uniformly heating the product, and a quenching tank for quenching the carburized product. A continuous gas carburizing apparatus comprising: a first inert and RX gas inlet tube for injecting inert and RX gas to discharge air in the carrying-in chamber; A first air discharge pipe communicating with the carrying room for discharging air due to the inertness into the carrying room and the injection of RX gas; A discharge chamber located between the carburizing zone and the scavenging tank to take out the carburized product into the sintering tank; A second inert and RX gas injection tube for injecting inert and RX gas to discharge air in the discharge chamber; It is achieved by the continuous gas carburizing apparatus according to the invention, characterized in that it comprises a second air discharge pipe connected to the discharge chamber for discharging the air according to the inert to the discharge chamber and the injection of RX gas.

In the above, the first and second air discharge pipes are preferably provided with check valves, respectively, to prevent the mixing of air from the outside into the carrying-in chamber and the carrying-out chamber.

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

2 is a view schematically showing a continuous gas carburizing apparatus according to the present invention. As shown in FIG. 2, the continuous gas carburizing apparatus 1 according to the present invention is a first inert and RX gas which injects inert and RX gas into the loading chamber 2 to discharge air in the loading chamber 2. The injection tube 3 is connected to the carrying room 2. Inert and RX gas is injected into the carrying-in chamber 2 through the 1st inert and RX gas injection pipe 3, and the air in the carrying-in chamber 2 is discharged | emitted to the outside.

The first air discharge pipe 4 is connected to the loading chamber 2 for discharging the air in the loading chamber 2 to the outside by inert and RX gas injection into the loading chamber 2, preferably from the outside. A check valve 5 is provided to prevent the mixing of air into (2).

Therefore, when the door 6 of the loading chamber 2 is opened, after the tray on which the material to be carburized is loaded is loaded into the loading chamber 2, the inert and RX gas is injected into the first inert and RX gas as described above. By injecting into the carrying-in chamber 2 through the pipe 3, the air in the carrying-in chamber 2 is discharged | emitted through the 1st air discharge pipe 4 to the outside. When the air is completely discharged from the carrying-in chamber 2, the door 7 is opened and the tray is transferred to the preheating region 8 so that the carburized material is subjected to the carburizing treatment as described in the prior art.

The carburized product is transferred to the discharge chamber 11 located between the carburizing zone 10 and the quenching tank 9, and the discharge chamber 11 also discharges inert and RX gas to discharge the air in the discharge chamber 11. A second inert and RX gas inlet tube 12 for injecting and a second air outlet tube 13 for discharging air according to the inertness into the discharge chamber 11 and the injection of the RX gas are provided. The second air discharge pipe 13 is also provided with a check valve 14 to prevent mixing of air into the discharge chamber 11 from the outside.

By having such a configuration, when the product is transported to the carrying out chamber 11, the door 15 is opened, and the product is transferred to the sintering tank 9 and quenched, and at this time, the product is mixed into the carrying out chamber 11 Air is discharged to the outside through the process as described above. Therefore, even if the next product tray is charged into the carburized region, the carburized region maintains a constant gas atmosphere, thereby preventing the induction of grain boundary layer on the product surface due to the incorporation of air.

The first and second inert and RX gas injection pipes 3 and 12 are provided with valves 16 for supplying and blocking the inert and RX gas to the loading chamber 2 and the discharge chamber 11, respectively.

According to the continuous gas carburizing apparatus according to the present invention having the structure as described above, when the product is loaded and unloaded, the mixing of air into the carburized region is prevented, thereby providing the grain boundary layer on the surface of the product due to the mixing of air. By minimizing the occurrence, it is possible to prevent degradation of product quality and durability.

Claims (2)

In a continuous gas carburizing apparatus comprising a carry-in chamber into which a product is carried in, a carburizing zone for preheating a product transferred from the carrying room to a predetermined temperature, carburizing and uniformly heating the product, and a hardening tank for hardening the carburized product. In A first inert and RX gas inlet tube for injecting inert and RX gas to discharge air in the carry-in chamber; A first air discharge pipe communicating with the carrying room for discharging air due to the inertness into the carrying room and the injection of RX gas; A discharge chamber located between the carburizing zone and the scavenging tank for carrying out to the sintering tank of the product; A second inert and RX gas injection tube for injecting inert and RX gas to discharge air in the discharge chamber; And a second air discharge pipe connected to the discharge chamber for discharging the air according to the inertness into the discharge chamber and the injection of the RX gas. The continuous gas carburizing apparatus according to claim 1, wherein the first and second air discharge pipes are preferably provided with check valves respectively for preventing the mixing of air from the outside into the inlet chamber and the outlet chamber.