RU2378440C1 - Method to transform operated rail track with joints into joitntless rail track - Google Patents

Abstract

FIELD: railway transport.

SUBSTANCE: rail ends are jointed together by aluminothermic welding with intermediate casting between rail ends. After aluminothermic welding, without waiting for complete cooling of rail ends welded together, metal is built up on rail upper surface in the zone adjoining welded seam. Notable abrasive processing of welded seam is made together with abrasive processing of built-up metal.

EFFECT: reduced amount of jobs.

10 cl, 5 dwg

Description

Technical field

The claimed group of inventions, which relates to the conversion of the existing butt rail track in continuous welding by aluminothermic welding in place without removing them from the canvas.

State of the art

The known advantages of a jointless track over a joint track, such as reducing metal consumption, lowering the main resistance to the movement of the train, reducing the cost of running the track, increasing the service life of the elements of the track’s top structure, reducing the power consumption for train traction, improving the reliability of electrically conductive rail chains, and achieving smooth contours of the path in curves, etc. Therefore, at present, work is underway on the Russian railways to convert butt rail tracks into jointless tracks. Such conversion includes welding of rail joints, including joints within railroad switches.

It is also known that the quality of a welded joint or a weld metal joint with a rail metal directly depends on the weldability of the materials. Rail steel refers to a group of materials containing a large amount of carbon, having poor weldability and prone to cracking during welding or surfacing.

At present, aluminothermal welding with intermediate casting between the ends of the rails, which provides high strength of the weld and its operability, is increasingly used to connect the joints of the railway track, including joints in the railroad switch zone. The closest analogue of the invention is the method of aluminothermic welding of rails according to patent RU 2088390, selected as a prototype, according to which aluminothermic welding of rails is carried out with intermediate casting between the ends of the rails, and then the abrasive treatment of the weld is carried out.

However, this method applies only to the method of welding rail joints, but does not provide for repair of the ends of the rails if they are damaged.

Meanwhile, the upper surfaces of the ends of the rails in the joint zone are often worn out or have defects in the form of chips, cracks in the shells. In this case, the wear zone or defects can extend from the end of the rail far beyond the weld. Thus, when converting a butt rail track to a jointless one on the upper surfaces of the ends of the rails, worn or defective portions may remain on both sides of the weld. As a result, the rail track after welding does not have the necessary quality characteristics and requires additional repair. The presence of large defects can serve as an obstacle to the welding itself.

It is also known that metal wear and a number of defects in rails or railroad switches can be eliminated directly in transit without removing the rails by using metal overlaying on a worn or defective section. This achieves resource saving and reducing the cost of repair and maintenance of the track. Surfacing metal on worn or defective sections of the track is the most common way to repair worn or defective sections of the upper surfaces of the rails on the existing track. Before its beginning, preliminary heating of the indicated sections is carried out, and after its completion, the abrasive treatment of the deposited metal is performed.

SUMMARY OF THE INVENTION

The present invention is the creation of such a method of converting a butt rail into a jointless one, in which not only the connection of the ends of the rails is carried out, but also the simultaneous restoration of the worn ends of the rails. The proposed method allows you to perform these operations in one technological window. This ensures the quality of the welded joint, saving time, labor and energy for work.

This problem is solved thanks to the development of a method for converting a butt rail to a jointless one, according to which the ends of the rails in the joint zone are joined by aluminothermic welding with intermediate casting between the ends of the rails, after which preliminary rough abrasive treatment of the weld is performed, then immediately, without waiting for the welds to cool completely of the ends of the rails, metal is deposited on the upper surface of the ends of the rails in the area adjacent to the weld, and the specified final abrasion The weld will be machined together with the abrasive treatment of the weld metal.

The upper surface of the ends of the rails in the area adjacent to the weld does not need to be heated for surfacing, since this surface is already heated due to welding. Thus, the heat from welding of the ends of the rails is used for surfacing the metal on the upper surface of the rails in the area adjacent to the weld. As a result, there is no need to spend time, effort and energy on heating the upper surface of the rails, which is usually carried out during surfacing. Saving time is especially important given the fact that work is usually carried out along the way.

Preferably between aluminothermic welding and surfacing, when the temperature at the weld takes on a value of about 1200 ° C, its profitable part is cut off. Thanks to this, the final abrasive treatment is facilitated and its time is reduced.

Preferably, the aluminothermic welding is performed so that the profitable part of the weld is partially or fully used as the weld metal. When removing the profitable part of the weld, an influx of at least 5 mm high is left.

Preferably, said sag is removed using pre-grinding at a temperature in the region adjacent to the weld from 600 to 900 ° C. Thanks to this, the final abrasive treatment is also facilitated and its time is reduced.

Metal surfacing on the upper surface of the ends of the rails in the area adjacent to the weld is preferably carried out at a temperature of 450-550 ° C. This allows you to ensure the quality of the connection of the weld metal with the metal of the rail, as well as to reduce the total time that is spent on connecting the ends of the rails and on the surfacing of the metal on the damaged ends of the rails. At the same time, the indicated temperature range is suitable for surfacing on the specified surface.

In a preferred embodiment, the final abrasive treatment is performed after cooling of the upper surface of the rails, when the temperature of the metal deposited on the upper surface of the rails takes on a value not higher than 100 ° C.

The final abrasive treatment is preferably performed over the entire width of the rail head, including working rounding.

Metal surfacing on the upper surface of the ends of the rails in the area adjacent to the weld can be mechanized by flux-cored wire.

Also, surfacing of metal on the upper surface of the ends of the rails in the area adjacent to the weld can be performed manually by electrodes.

Brief Description of the Drawings

Figure 1 shows the worn ends of the rails in the joint area.

On figa shows in cross section a detachable form in place of the weld gap at the beginning of the weld metal pouring.

Fig. 2b shows in cross-section a detachable form at the weld gap when the weld metal pouring is completed.

Figure 3 shows the ends of the rails after carrying out aluminothermic welding, the weld and its profitable part.

Figure 4 shows the welded ends of the rails after surfacing.

Figure 5 shows the welded ends of the rails after the final abrasive treatment.

The following is an example of a method for converting an existing butt rail into a jointless rail.

When implementing the inventive method, before starting welding, a gap of the required width is created between the ends of the rails. The width of the gap can be 50 mm or 75 mm. In the example described below, the gap width in the drawings designated s is 50 mm. Before starting the installation of a detachable form, the ends of the rails are prepared for surfacing. The preparation includes dry cleaning of dirt, wiping dry with wiping materials, removing surface defects with a grinding wheel, and treating places of chipping with a grinding wheel to remove delaminations and cracks. The length of the sanding area should be 4 mm longer than the length of the chipping. It should be noted that to compensate for the deflection of the joint caused by shrinkage, the ends of the rails can be raised before welding (not shown in the drawings).

Figure 1 shows the worn ends 1 of the rails. Between the ends 1 of the rails there is a gap s. Positions I and II indicate worn sections of the ends of the rails. Positions 2 and 3 indicate sleepers and soil, respectively.

Before thermite welding, the rails are preheated to a temperature of 900-1000 ° C using a gas burner (not shown in the drawing). Then the reaction crucible and the mold are installed, a thermite reaction is carried out, and molten welded metal is released, which fills the internal cavity of mold 4 for 4-5 s.

On figa, 2b shows in cross section a detachable form 4, which is placed around the weld gap s. Figa, 2b illustrate the process of pouring steel into a split mold. On figa shows how the flow of the welded liquid metal 5, which is released from the crucible (not shown in the drawings), where the stratification of the welded metal 5 and slag 6 has already occurred, falls on the crossbar 7 and is divided into two parts, which are in the channels 8 between the bolt 7 and the walls of the detachable form 4 fall into the welded gap s and, washing the ends of the rails 1 vertically, reach the bottom of the mold, and then fall into the side outlets 9. This ensures the necessary “flushing” mode, guaranteed melting of the ends of the rails to a depth of not less than 3 mm, slag 6 localization tsya outside the rail section and misses the welding gap s, and the gases are ejected upward. The direction of the arrow in figa indicates the direction of release of the welded metal.

Figure 3 shows the ends of rails 1 after carrying out aluminothermic welding, weld 10 and its profitable part 11. After aluminothermic welding, molten welded metal poured into the mold crystallizes within 4.5-5 minutes. When the temperature of the weld 10 takes the value of 1200 ° C, its profitable part 11 is cut off. In the drawings, the cut line is indicated by a dotted line. The entire length of the profitable part 11 of the weld 10 is partially or fully used as a weld metal. The length of the profitable portion 11 of the weld 10 is indicated by f.

Figure 4 shows the ends of the rails 1 after the profitable part 11 of the weld 10 is removed. When removing the profitable part 11 of the weld 10, an influx of not less than 5 mm high is left (not shown in the drawing), which is removed at a temperature of the upper surface of the rails of 600-900 ° C using preliminary hot grinding.

When the temperature of the rails drops to 450-550 ° C, metal is deposited on the upper surface of the damaged sections I and II of the ends of the rails 1 adjacent to the weld 10. The lengths of the welded sections 12 on both sides of the weld 10 correspond to the length of the damaged section. 4, the indicated length is indicated by d.

In an embodiment according to the present invention, mechanized surfacing is carried out. When surfacing rails of type P65, flux-cored wire Tubrodur 15.43 with a diameter of 1.6 mm or electrodes of the brand HP-70 with a diameter of 5 mm are used.

When metal is deposited onto the upper surface of damaged sections of rail ends by electrodes, the optimum deposition mode is achieved with the following parameters: reverse polarity current of 200-240 A and average arc length. When surfacing, the roller is applied around the perimeter of the damage being repaired and surfacing begins on the side of the inoperative part of the rail. The rollers are applied in the transverse direction to the entire width of the rail head, starting from the non-working side. The previously deposited bead is overlapped by 1/3, so that there are no undercuts and irregularities. The crater is brought to the weld metal and melted.

Then, the final abrasive treatment of the weld metal is carried out together with the weld. Figure 5 shows the ends of the rails 1, fully fixed in fasteners (not shown in the drawing) before starting the final abrasive treatment. The final abrasive treatment is performed with an abrasive tool after natural cooling of the upper surface of the rails 1, when the temperature of the metal deposited on the upper surface of the rails becomes no higher than 100 ° C. In Fig. 5, the length of the upper surface of the ends of the rails on which the final abrasive treatment is performed is indicated by L.

The final abrasive treatment is carried out by grinding the deposited metal and the weld to the level of the upper surface of the rail, not subjected to surfacing. The meter line 13 is used to control measurements, applying its center to the center of the weld 10. The size of the gaps and at the ends of the line should not exceed the normalized tolerance.

Claims (10)

1. A method of converting an existing joint rail to a jointless one, according to which the ends of the rails in the joint zone are joined by aluminothermic welding with intermediate casting between the ends of the rails, after which the final abrasive treatment of the weld is performed, characterized in that after the aluminothermic welding, without waiting for the final cooling welded ends of the rails, metal is deposited on the upper surface of the rails in the area adjacent to the weld, and the specified final abrasive machining the weld is welded together with the abrasive treatment of the weld metal. 2. The method according to claim 1, characterized in that between aluminothermic welding and surfacing, when the temperature at the weld takes the value of 1200 ° C, its profitable part is cut off. 3. The method according to claim 2, characterized in that the aluminothermic welding is performed so that the profitable part of the weld is partially or wholly used as a weld metal in the weld zone. 4. The method according to claim 3, characterized in that when removing the profitable part of the weld, an influx of at least 5 mm high is left. 5. The method according to claim 4, characterized in that the specified influx is removed using preliminary hot grinding at a temperature in the area adjacent to the weld, 600-900 ° C. 6. The method according to any one of claims 1 to 5, characterized in that the surfacing of the metal on the upper surface of the ends of the rails in the area adjacent to the weld is carried out at a temperature of 450-550 ° C. 7. The method according to claim 1, characterized in that the final abrasive treatment is performed at a temperature of the metal deposited on the upper surface of the rails, not higher than 100 ° C. 8. The method according to claim 1 or 7, characterized in that the final abrasive processing is performed over the entire width of the rail head, including the working rounding. 9. The method according to claim 1, characterized in that the metal is deposited on the upper surface of the ends of the rails in the area adjacent to the weld, mechanically produced by cored wire. 10. The method according to claim 1, characterized in that the metal is deposited on the upper surface of the ends of the rails in the area adjacent to the weld, produced by electrodes manually.

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