KR20010077051A - Method and apparatus for heat treated slack quenching of rails - Google Patents

Abstract

PURPOSE: A method and apparatus for heat treatment of a rail is provided to enhance quality of the rail and minimize deformation of the rail by enhancing friction resistance through curing processes of a rail head. CONSTITUTION: An apparatus for heat treatment of a rail includes a rail pre-heating unit(20), a rail head heating unit(40), a rail slack quenching unit(60) and a mist cooling unit(100). The rail pre-heating unit(20) has a heater(30) for pre-heating the whole portion of a rail(10). The rail head heating unit(40) is installed to heat a rail head. The rail slack quenching unit(60) has nozzle boxes(80) for injecting compressed air to cool the rail head for transformation of the rail head into a fine pearlite structure. The mist cooling unit(100) keeps the temperature difference between the rail head and a lower part at a certain range, and has an injection nozzle(120) for injecting an air mist to the rail head in multi-steps to prevent bending deformation due to temperature difference between the rail head and the rail lower part.

Description

Heat treatment method and apparatus of rail {METHOD AND APPARATUS FOR HEAT TREATED SLACK QUENCHING OF RAILS}

The present invention relates to a method and apparatus for heat treatment of a rail which can improve the quality and service life of a rail by increasing the wear resistance of the head, which is a running surface of a railway rail, which is abrasion due to contact with a wheel while driving a train. Through the quenching nozzle box, only the head of the heated rail is slowly cooled by using compressed air to obtain fine pearlite structure, and high pressure, a mixture of water and compressed air, is used to prevent bending deformation due to the temperature difference between the rail head and the bottom. Air Mist is sprayed in multiple stages to cool the head of the rail, reducing the production cost by reducing the amount of compressed air for heat treatment of the slacks quenching, and reducing the cost of production. Heat treatment method of rail which minimizes bending deformation over and makes rail production continuous And to an apparatus.

In general, as the weight of a railway vehicle increases and the speed increases, the wear rate of the running surface of the rail head, which is the running surface of the rail which is in direct contact with the wheels of the railway rail, is gradually intensified, causing local deformation and damage due to the repeated load of the vehicle, and fatal fracture. This will occur, thereby reducing the life and stability of the rail, according to the situation that the cost of repair and replacement of the rail is increasing.

Accordingly, to improve the wear resistance by improving the mechanical properties such as the appropriate level of strength and hardness for the head, the running surface of the rail, heat treatment of the head of the rail to improve the quality of the rail, heat treatment of the rail For this purpose, the rail material is reheated to a high temperature zone and quenched and cooled by an appropriate cooling method. In this case, the rail is reheated by heating above the Ac ₃ transformation point, which is a temperature for changing the internal structure, and then using the appropriate cooling medium. Cooling by adjusting the cooling rate, you can obtain a high-quality rail with improved wear resistance with the appropriate level of strength and hardness.

In the conventional rail heat treatment method associated with this technique, as in Korean Patent Publication No. 87-9469, the rail is heated to 538 ^o C below the metallurgical transformation temperature Ac ₃ transformation point, and then the head and The bottom is heated to about 1038 ^o C and 816 ^o C, and the head and bottom are quenched and heat treated again to 538 ^o C for its surface texture to increase the wear resistance of the rail surface through water spray cooling to room temperature. .

In such a case, immediately after reheating the bottom of the rail separately and simultaneously with the head, a large amount of power ratio and compressed air flow are required during air quenching, and when spraying water through the nozzle to room temperature to cool the rail. In other words, there is a disadvantage in that a great waste of energy occurs.

In addition, in the rail heat treatment method according to Korean Patent Publication No. 86-5040, a nozzle is placed around a rail maintained at a high temperature in the hot rolled or separately reheated austenite region for heat treatment of a light rail having various strength levels. By installing, the gas is cooled by spraying a gaseous cooling medium until the rail head portion is transformed into fine grained tissue.

In the heat treatment method, by using compressed air as a cooling medium for cooling the head of the rail, a lot of equipment and power for the generation of the compressed air are required, which leads to an increase in production cost and an uneconomical disadvantage.

In addition, in recent years, a method for heat treatment of rails according to Korean Patent Application Publication No. 96-4335 is known, which is a method in which a rail that is plastically deformed into a final shape during hot rolling is not heated separately without using a high heat contained therein. a 750~1100 ^o and kept at C, the rail by heat radiation in the air and uniformly cooled to a natural cooling process of less than 820-860 ^o C with 5~120 than the Ar ₃ transformation temperature to ^o C, if the running of the vehicle Immerse and cool the in-rail head in the range of 800 to 450 ^° C.

At the same time as the above cooling, the bottom of the rail is sprayed and cooled by spraying compressed air or a mixture of air and water in an air mist state, thereby curing the head of the rail while maintaining uniform deformation of the rail, and abrasion resistance. To increase.

However, in order to cool the rail head, a separate coolant immersion tank or a coolant container is required, and a rail rotator for immersion of the rail head is additionally required, so that initial equipment investment and in-line There are many problems, such as requiring an installation space for the (IN-LINE) method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The object of the present invention is to preheat the entire rail, reheat only the head of the rail, and then slack quench only the head of the material rail by the separation of compressed air. Through the heat treatment process, it can transform into fine pearlite structure, which improves the mechanical properties of the wear resistance, which increases the strength and hardness of the rail head, and in particular, improves the wear resistance due to the hardening of the rail head. It is to provide a method and apparatus for heat treatment of a rail to minimize rail deformation.

It is another object of the present invention to minimize the production cost by using compressed air only in the slack quenching portion, and to minimize the bending deformation over the entire length of the rail by spraying the air mist immediately after the heat treatment of the rail, thereby producing a high quality heat treated rail continuously. It is to provide a method and apparatus for heat treatment of a rail that can be made stable.

1 is a schematic configuration diagram of a heat treatment apparatus for slack quenching heat treatment of a rail according to the present invention.

2 is a schematic structural diagram of a rail preheating unit of the present invention.

3 is a schematic structural diagram of a rail head heating unit of the present invention;

4a and b are respectively showing the rail quenching unit according to the present invention.

5 is a schematic configuration diagram of an air mist cooling unit for preventing rail warpage deformation of a rail heat treatment apparatus according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10 ... rail 10a ... tofu

10b ... bottom 20 ... rail preheater

30.Preheater heater 40 ... Rail tofu heating unit

50 ... main heater 60 ... rail quenching unit

70 ... Compressed air 80 ... Nozzle box

90 ... Quenching nozzle 100 ... Air mist cooling section

110.Air mist 120.Air mist spray nozzle

130 ... roller

As a technical configuration for achieving the above object, the present invention, the rail preheating is provided with a preheat heater which is installed in the rail head and both sides, the bottom respectively to heat the entire rail transported through the rollers first Wealth,

A rail head heating unit in which a main heater is installed on the head of the rail so as to be reheated to a predetermined temperature region above the stable Ac ₃ transformation temperature on the head of the rail passing through the preheater;

After the transfer of the head of the reheated rail in the air for a predetermined time to maintain a uniform temperature, the air is sprayed to the upper side of the head and both sides of the head to cool with compressed air in a predetermined temperature range so that the rail head is transformed into fine pearlite tissue. A rail slack quenching unit on which nozzles are installed,

It provides a rail heat treatment apparatus, comprising an air mist cooling unit for preventing the bending deformation due to the temperature difference between the quenched rail head and the rail bottom, and injecting the air mist to the rail head in multiple stages for cooling the air mist. By

In addition, the material rail of the coarse pearlite structure is preheated to about 500 to 600 ^o C through the electric induction heating device, and the head of the preheated rail is at or above Ac ₃ transformation temperature which becomes a stable austenite structure. 800~1000 ^o C, and reheating at a constant temperature zone of the section, and then transferring the predetermined time wait is complete, the head of the re-heating rail is maintained at a uniform temperature, 800 to which the rail head so that the transformation into fine pearlite tissue 500 ^o C Inject the compressed air into the head of the rail using the compressed air in the predetermined temperature range, and then quench the slag, and pressurize the high-pressure air mist, which is a mixture of water and compressed air, to suppress the deformation of the rail length due to the temperature difference between the head and the bottom of the rail. Air Mist) by spraying in multiple stages and the cooling temperature of the rail head to 200~250 ^o C, natural cooling the entire portion of the rail down to room temperature sat A method of heat-treating a rail according to the maryeonham.

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

1 is a schematic configuration diagram of a heat treatment apparatus for slack quenching heat treatment of a rail according to the present invention, Figures 2 and 3 is a schematic structural diagram of a rail preheating unit of the present invention and a schematic structure diagram of a rail head heating unit of the present invention, The rail heat treatment apparatus of this invention consists of the rail preheating part 20, the rail head heating part 40, the rail quenching part 60, and the air mist cooling part 100.

Rail preheating unit 20 for heating the entire rail 10, as shown in Figure 2, in order to heat the entire rail 10 transported through the roller 130, the head, both sides, the bottom of the rail 10 Preheating heaters 30, which are each electric induction heating apparatuses, are installed in the heaters to preheat the entire rail 10 to about 500 to 600 占 폚.

In addition, the rail head heating unit 40 for heating the head 10a of the preheated rail 10 to a predetermined temperature, as shown in FIG. 3, the head 10a of the rail 10 passing through the preheating heater 30. Only the head 10a of the rail 10 as the main heater 50 is reheated to a temperature range of about 800 to 1000 ° C. above the stable Ac ₃ transformation temperature.

The rail slack quenching unit 60 for changing the structure of the head of the reheated rail 10 is maintained at a uniform temperature at the head 10a of the reheated rail 10 as shown in FIGS. 4A and 4B. After the transfer to the air for a predetermined time, the temperature of the rail head is cooled to 800-1000 ° C. so that the head 10a of the rail 10 is transformed into fine pearlite structure, and at this time, the nozzle box 80 As shown in FIG. 4A, the air injection nozzles 81 are respectively installed on the upper side of the head and the both sides of the head so as to be cooled by compressed air, or as shown in FIG. 4B, the nozzle box 80 is mounted on the rail 10. It is integrally installed on the head and both sides of the head to be integrally installed, so that the head 10a of the rail 10 is subjected to slack quenching heat treatment.

In addition, the air mist cooling unit 100 for cooling the head 10a of the slack quenching heat-treated rail 10, as shown in Figure 5, of the head 10a and the rail bottom 10b of the rail 10 The spray nozzle 120 is installed to prevent the warpage deformation caused by the temperature difference and to spray the air mist 110, which is a mixture of water and compressed air, in multiple stages on the rail head 10a to cool the rail head. It consists of a configuration that is installed to cool the furnace.

Referring to the embodiment of the heat treatment method of the present invention having such a configuration in detail as follows.

Electrically induction heating in which the rails 10 are preheated with electric induction heating coils are transferred by transferring the material rails of coarse pearlite structure in which the chemical composition of carbon steel is metallurgically applied through the rail conveying roller 130. The entire heating rail is heated through a preheating heater 30 which is a device, wherein the preheating heater 30 is the electric induction heating apparatus on the head, both sides and the bottom of the rail 10 according to the shape of the rail 10. The phosphorus preheat heater 30 is installed to preheat the entire rail 10 to about 500 to 600 ° C.

As described above, the pre-heated rail 10 material reheats its head 10a to a temperature equal to or greater than Ac ₃ transformation point, where the austenite structure is stable, and at this time, the head 10a of the rail 10 has a main heater. 50 is installed to reheat the rail head to a constant temperature region of about 800 to 1000 ℃ section.

Subsequently, the head 10a of the reheated rail 10 as shown in FIG. 2 so as to reheat only the head 10a of the rail 10 material as described above to transform the head of the rail into a fine pearlite structure having excellent wear resistance. ) Is transported in the atmosphere for a predetermined time to maintain a uniform temperature, the temperature of the head of the rail is cooled to 800 ~ 500 ℃ by using compressed air, at this time, the nozzle box (80) for the injection of the compressed air 70 Nozzle box 80 provided with the injection nozzle 81 to cool the compressed air in the air) is installed to the upper side of the head and both sides of the head, respectively, to perform the slack quenching heat treatment of the rail head. Tofu can be transformed into fine pearlite tissue.

As described above, in the rail 10 in which the slack quenching heat treatment is completed, the bending of the rail electric field occurs due to the temperature difference between the head 10a and the bottom 10b of the rail by heating only the rail head 10a. In order to minimize the deformation of the bending over the entire length of the rail, the head of the rail is sprayed with an air mist (Air Mist) 110, a mixture of water and compressed air using the injection nozzle 120 to the rail head (10a) ) Is cooled to 200-250 ° C.

At this time, the cooling of the rail head is as shown in Figure 2, the nozzle box for the injection of the air mist 110, of the air mist nozzle 120 is installed on the head 10a which is the running surface of the rail 10 By installing in multiple stages so that the position may be gradually lowered, the flow rate of the air mist injection nozzle 120 is adjusted to minimize the bending deformation over the rail length caused by the temperature difference between the rail head 10a and the bottom 10b. It is.

On the other hand, the rail 10 passed through the air mist injection nozzle 120 as described above, by allowing the entire portion of the rail to be naturally cooled to room temperature, the rail production can be made continuously.

As described above, according to the method and apparatus for heat treatment of a rail according to the present invention, after preheating the entire rail part and reheating only the rail head part again, only the head part of the material rail is subjected to a slack quenching heat treatment process through the separation of compressed air. By transforming into a light structure, the mechanical properties of the wear resistance are increased by increasing the strength and hardness of the rail head, and in particular, the wear resistance of hardening the rail head is improved to improve the quality of the rail and minimize the rail deformation. By using compressed air only in the slack quenching part, the production cost is minimized, and the bending deformation over the entire length of the rail due to the spraying of the air mist immediately after the heat treatment of the rail is minimized, so that the production of high quality heat treated rail can be made continuously and stably. That would have an excellent effect.

While the invention has been shown and described with respect to specific embodiments thereof, it will be appreciated that various changes and modifications can be made in the art without departing from the spirit or scope of the invention as set forth in the following claims. Those of ordinary skill will want to know easily.

Claims (4)

In the heat treatment apparatus of the rail, A rail preheating unit 20 for preheating the entire rail 10 at a predetermined temperature by installing a preheating heater 30 which is an electric induction heating device for heating the entire rail 10 transferred through the roller 130, Rail head heating unit 40 installed on the rail head 10a to be reheated as the main heater 50 at a constant temperature equal to or higher than the stable Ac ₃ transformation temperature on the head 10a of the rail 10 passing through the preheating heater 30. Wow, After the head 10a of the reheated rail 10 is transported in the atmosphere for a predetermined time to maintain a uniform temperature, the head of the rail 10 is cooled so that the head of the rail is transformed into fine pearlite tissue, and the compressed air 70 The nozzle box 80 is respectively installed on the upper side of the head and both sides of the head to cool the compressed air in the nozzle box 80 for injection, and the rail is installed to perform the slack quenching heat treatment of the rail head. Slack quenching unit 60, and It prevents the bending deformation due to the temperature difference between the head 10a of the rail 10 and the rail bottom 10b, and the high pressure air mist 110, which is a mixture of water and compressed air, is cooled in multiple stages to the rail head 10a. Rail nozzle heat treatment apparatus characterized in that it comprises an air mist cooling unit 60 is installed so that the injection nozzle 120 is installed to maintain the temperature difference between the rail head and the bottom to be sprayed. 2. The rail heat treatment apparatus according to claim 1, wherein the heating temperature of the entire rail (10) through the preheat heater (30) installed in the rail preheater (20) is heated to about 500 to 600 ° C. The rail heat treatment apparatus according to claim 1, wherein the main heater (50) installed on the rail head (10a) reheats the rail head (10a) at a temperature of 800 to 1000 ° C. In the method of heat treatment of the rail, The preheated heater rail is heated to 500 ~ 600 ℃ through the preheat heater, which is an electric induction heating device, and the head of the preheated rail has a stable austenite structure above about Ac ₃ transformation temperature. Reheating through the main heater to a constant temperature zone of 800 ~ 1000 ℃ section, after the transfer in the air for a certain period of time so that the head of the reheated rail is maintained at a uniform temperature, about 800 so that the rail head is transformed into fine pearlite texture In the predetermined temperature range of -500 ℃, the nozzle box is sprayed to the head of the rail by using high pressure air to slack quench heat treatment, and then the water and compression are suppressed to suppress the deflection of the rail length due to the temperature difference between the head and the bottom of the rail. The high pressure air mist, which is an air mixture, is sprayed in multiple stages to cool the temperature of the head of the rail to 200-250 ° C, Up on heat treatment of the rail characterized in that the natural ever cooling the entire portion of the rail.