JP2021074756A - Method and device for cooling rail welded part - Google Patents

Abstract

To shorten a welding time including finishing by enabling grinding of a rail top surface even during cooling after thermite welding.SOLUTION: A method for cooling a rail welded part includes the steps of: spraying mist M from both sides of a web part 10S except for a top surface 10T of a rail 10 so as not to spray the mist M at the top surface 10T of the rail 10 when cooling a welded part 10J of the rail 10 where the top surface 10T of the rail 10 is ground after thermite welding; and grinding the top surface 10T of the rail 10 while spraying the mist M.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method and apparatus for cooling a rail weld, and more particularly to a method and apparatus for cooling a rail weld, which is suitable for use in thermite welding and can shorten the welding time including finishing.

In recent years, in order to reduce railway track maintenance costs and noise and vibration, long rails with continuous seams by welding are becoming widespread. As the welding method, a flash welding method, a gas pressure welding method, an enclosed arc welding method, a thermite welding method and the like are used. Of these, in the thermite welding method, a powder solvent of iron oxide and aluminum is subjected to a redox reaction (thermite reaction) in a pot placed on the rail weld, and the generated molten metal is surrounded by a dry mold. It is a method of pouring and welding between the end faces of two rails, and is widely used as a field welding method for rails (Patent Documents 1 to 3). In addition, rapid thermite welding by short-time preheating, which is called gold summit (GS) welding, is also used. Hereinafter, the termite welding including the gold summit welding will be collectively referred to.

Regardless of the welding method, it is necessary to quickly cool the high-temperature rail weld, but the applicant in Patent Document 4 states that the rail is cooled with mist (also referred to as rare water) until the rail temperature drops to a predetermined temperature. , We are proposing a technology to cool with water after the temperature drops to a predetermined temperature.

Japanese Unexamined Patent Publication No. 11-58042 JP-A-2002-263866 Japanese Unexamined Patent Publication No. 2004-188455 Japanese Unexamined Patent Publication No. 2019-81917

The top surface of the rail after thermite welding needs to be rough-finished with a grinding machine and then finally finished, but with the conventional thermite welding method, water cannot be applied while the top surface of the rail is rough-finished. Therefore, as illustrated in the case of gold summit (GS) welding in FIG. 1 (A), the rail top surface is roughly finished immediately after welding with a grinder or the like, and then the final finish is performed when the temperature drops. It had the problem that it took time.

On the other hand, Patent Document 4 proposed by the applicant describes a mist cooling method, but it is not very effective because not only gas pressure welding is the main target but also GS welding has a mold. Further, in the embodiment, since the nozzle (head nozzle) is also arranged on the top surface of the rail head, it is still difficult to perform rough finishing during cooling.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to enable grinding of the top surface of the rail even during cooling after welding and to shorten the welding time including finishing.

In the present invention, mist is applied from both sides of the abdomen excluding the crown surface of the rail so that mist does not get on the crown surface of the rail when cooling the welded portion of the rail on which the crown surface of the rail is ground after welding. By spraying, the above-mentioned problem is solved.

Here, the welding can be thermite welding.

Further, the crown surface of the rail can be ground while the mist is being sprayed.

Further, the mist can be sprayed toward the boundary between the abdominal mold of thermite welding and the rail.

Further, a shield that blocks a part of the mist can be arranged in front of the cooling nozzle that sprays the mist.

The present invention is also a rail welded portion cooling device for cooling a rail welded portion in which the crown surface of the rail is ground after welding, and the rail is provided so that mist is not applied to the crown surface of the rail. A plurality of cooling nozzles for spraying mist from both sides of the abdomen excluding the top surface of the head, and a nozzle jig disposed on the rail for arranging the plurality of cooling nozzles toward the abdomen of the rail. A fixing means for fixing the nozzle jig on the rail, a cooling liquid supply means for supplying a cooling liquid for mist spraying to the plurality of cooling nozzles, and a mist spraying means for the plurality of cooling nozzles. The same problem is also solved by a cooling device for a rail welded portion, which is provided with a gas supply means for supplying gas.

Here, the welding can be a thermite welding.

Further, the nozzle jig can be provided with a space capable of grinding the crown surface of the rail during mist spraying.

Further, the number of the plurality of cooling nozzles can be four or more.

Further, the spray angle of the cooling nozzle can be set to 20 ° or more and less than 110 °.

Further, a shield provided in front of the cooling nozzle to block a part of the mist can be further provided.

According to the present invention, since the top surface of the rail can be ground even during cooling after welding, the welding time including finishing can be shortened as illustrated in FIGS. 1 (B) and 2 (C). It becomes. FIG. 2A is an example of a normal cycle time of gold summit (GS) welding, and FIG. 2B is an example of a cycle time during natural cooling (air cooling).

Diagram showing a comparison of the cooling state of the gold summit welded portion of the rail between (A) a conventional example and (B) an embodiment of the present invention. The figure which compares and shows an example of the cycle time of (A) normal time, (B) natural cooling time, and (C) mist cooling time according to the present invention of gold summit welding. (A) plan view and (B) side view showing the main part configuration of the first embodiment of the present invention. (A) plan view, (B) front view, (C) side view, and (D) front view, which also show detailed configurations, are cross-sectional views taken along the line AA. The figure which shows the state immediately after the gold summit welding in the embodiment of this invention. Cross-sectional view showing an example of arrangement of cooling nozzles Similarly, a cross-sectional view showing a modified example of the arrangement of the cooling nozzles. A diagram showing an example of a cooling curve as well. Similarly, a diagram showing an example of the shore hardness of the top surface of the rail. Side view which shows the main part structure of 2nd Embodiment of this invention Cross-sectional view showing an example of arrangement of cooling nozzles

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments and examples. Further, the constituent requirements in the embodiments and examples described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the components disclosed in the embodiments and examples described below may be appropriately combined or appropriately selected and used.

The main configuration of the first embodiment of the present invention is shown in FIG. 3, and the detailed configuration is shown in FIG.

This embodiment is a cooling device for a rail welded portion for cooling the welded portion 10J of the rail 10 welded at the gold summit, and is a crown surface of the rail 10 so that mist M is not applied to the crown surface 10T of the rail 10. A plurality of cooling nozzles 20 for spraying mist M from both sides of the abdomen 10S excluding 10T (two on each side in the first embodiment, a total of four) and the plurality of cooling nozzles 20 are arranged toward the abdomen 10S of the rail 10. A nozzle jig 30 arranged on the rail 10 for the gas, a rail catch 40 (see FIG. 4) for fixing the nozzle jig 30 on the rail 10, and mist on the plurality of cooling nozzles 20. A coolant supply pipe 42 (see FIG. 4) and a coolant tank (not shown) for supplying a coolant for spraying (for example, water) and a gas for mist spraying (for example, compressed air or nitrogen gas) are also supplied. It is provided with a gas supply pipe 44 (see FIG. 4) and a gas supply source (not shown) such as a gas compression compressor (for example, an air compressor) or a gas cylinder (for example, a nitrogen gas cylinder). In the figure, 10B is the bottom of the rail.

The state immediately after welding the Gold Summit is shown in FIG.

Both ends of the nozzle jig 30 are arranged on the rail top surface 10T sandwiching the rail welded portion 10J, and a space S for grinding (see FIG. 4B) is provided between them. A rail catch 40 for fixing to the rail 10 is provided on one side of the nozzle jig 30.

The cooling nozzle 20 can be, for example, a two-fluid spray nozzle capable of giving a flow velocity of a compressed gas to a droplet. In this case, a separate mist generating means is not required, and the configuration is simple. A separate mist generating means can also be used.

The ratio of the gas to the coolant of the mist M can be, for example, 0.3: 0.17, but depending on the rail size, for example, in the case of a 60 kg rail, the gas is 0.2 to 0.4: cooling. In the case of liquid 0.2 to 0.17, 50 kg rail, gas 0.3: coolant 0.2 to 0.15, etc. can be appropriately changed.

The spray angle δ of the cooling nozzle 20 can be, for example, 20 ° or more and less than 110 °. If it is less than 20 °, the spray range of mist M becomes narrow. On the other hand, if the spray angle δ is 110 ° or more, there is a risk that mist M will be applied to the rail top surface 10T.

The distance B between each cooling nozzle 20 and the rail abdomen 10S can be set to, for example, 100 mm in consideration of the influence of heat. Since the spraying direction is desired to be directed to the center of the welded portion as much as possible, the cooling nozzle 20 can be directed inward and the target portion of spraying can be directed to the boundary line between the abdominal mold 50 and the rail 10. The test was conducted with the distance A between the left and right cooling nozzles 20 set to 200 mm, but in order to further improve the cooling effect, it is considered more effective to reduce the distance from the cooling nozzles 20 to the rail 10 in the spray direction, so set it to 180 mm. changed. As a result, the injection angle θ was about 20 ° inward. In this way, the interval A can be set to, for example, 180 mm, and the injection angle θ can also be set to 20 °. Further, the height C of each cooling nozzle 20 can be, for example, 70 mm.

FIG. 6 shows an example of arrangement of the cooling nozzles 20 in the case of a 60 kg rail.

In the example of FIG. 6A, the cooling nozzle 20 having a spray angle δ = 45 ° is horizontally arranged below the rail top surface 10T by C = 70 mm. As is well shown in FIGS. 3 (A) and 4 (A), the cooling nozzle 20 has an injection angle θ = 20 ° and is inward, so that the actual distance between the cooling nozzle 20 and the rail abdomen 10S B'is 110 mm. In the figure, an example of the flow rate distribution when the air pressure Pa = 0.3Ma and the hydraulic pressure Pw = 0.15 MPa is shown.

In the example of FIG. 6B, the cooling nozzle 20 having a spray angle δ = 80 ° is horizontally arranged below the rail top surface 10T by C = 100 mm.

In the example of FIG. 6C, the cooling nozzle 20 having a spray angle δ = 80 ° is arranged diagonally downward at α = 20 ° below C = 60 mm from the rail top surface 10T.

As a modification, FIG. 7 shows an example in which a columnar shield 22 having a diameter of E = 6 mm is added at a position of D = 20 mm in front of the cooling nozzle 20 in FIG. 6 (B). Abdominal cooling can be suppressed by this shield 22. The position, size, and cross-sectional shape of the shield 22 are not limited to this.

Almost the same arrangement as in FIGS. 6 and 7 is possible for a 50 kg rail that is slightly smaller than the 60 kg rail.

In the nozzle arrangement of FIG. 6A, the cooling nozzle 20 having a spray angle δ = of 45 ° is used to cool the air pressure Pa at 0.3 MPa, the air flow rate Qa at 31 L / min, and the coolant pressure Pw at 0.2 MPa. When the liquid flow rate Qw is 8.5 L / hour, as illustrated in FIG. 8, even in the gold summit welded portion where the center of the rail head reaches 1180 ° C., all of them are cooled by mist for 6 minutes from the internal temperature of 800 ° C. It was confirmed that the temperature of the site was lowered to 300 ° C. or lower almost evenly. In addition, the time after the completion of steel removal decreased in less than 15 minutes.

The shore hardness distribution measured on the rail top surface 10T after the finishing work is as illustrated in FIG. 9, and the weld metal hardness shows a high hardness of around HS46 with respect to the rail base material hardness HS36 to 37. Was confirmed. Since the weld metal hardness of the gold summit welded portion subjected to the normal cooling work is about HS40 to 42, the hardness of the weld metal is slightly increased by the mist cooling work of the present invention.

The gas pressure / flow rate, the coolant pressure / flow rate, the cooling nozzle interval A, the distance B between the cooling nozzle 20 and the rail abdomen 10S, the cooling nozzle height C, the injection angle θ, the spray angle δ, and other values can be changed as appropriate. Is clear. The ratio of gas to coolant is also not limited to gas 0.3: coolant 0.17. The type of coolant is not limited to water, and the type of gas is not limited to air.

Further, in the first embodiment, the number of cooling nozzles 20 is two each on the left and right, for a total of four, but as in the second embodiment illustrated in FIG. 10, the number of cooling nozzles in the left and right cross sections It is also possible to make a total of eight cooling nozzles on the left and right sides of the rail welded portion by setting two of each of 20A and 20B to a total of four.

FIG. 11 shows an example of arranging the cooling nozzles 20A and 20B with respect to the 60 kg rail 10 in the second embodiment.

A cooling nozzle 20A with a spray angle δ = 45 ° is placed upward at β = 26 ° at _{a distance C 1} = 70 mm from the rail top surface 10T _{, and cooling with a spray angle δ = 45 ° is also placed at a position C 2} = 125 mm. The nozzle 20B is arranged in the horizontal direction.

In this case, the cooling performance can be further improved.

Almost the same arrangement is possible for a 50 kg rail.

The number of cooling nozzles is not limited to four or eight, and may be, for example, two, six, or ten or more.

In the above embodiment, the present invention has been applied to cooling the rail welded portion of the gold summit welded, but the application of the present invention is not limited to this, and thermite welding other than the gold summit welding and after welding The same applies to cooling rail welds by other methods in which the top of the rail is ground.

10 ... Rail 10J ... Rail welded part 10S ... Rail abdomen 10T ... Rail crown surface 20, 20A, 20B ... Cooling nozzle 22 ... Shield 30 ... Nozzle jig 40 ... Rail catch 42 ... Coolant supply pipe 44 ... Gas supply pipe 50 … Abdominal mold M… Mist S… Grinding space

Claims (11)

After welding, the top surface of the rail is ground. When cooling the welded part of the rail,
A method for cooling a rail welded portion, which comprises spraying mist from both sides of the abdomen excluding the parietal surface of the rail so that mist does not get on the parietal surface of the rail. The method for cooling a rail welded portion according to claim 1, wherein the weld is a thermite weld. The method for cooling a rail welded portion according to claim 1 or 2, wherein the crown surface of the rail is ground while the mist is sprayed. The method for cooling a rail welded portion according to claim 2, wherein the mist is sprayed toward a boundary portion between the abdominal mold of thermite welding and the rail. The method for cooling a rail welded portion according to any one of claims 1 to 4, wherein a shield that blocks a part of the mist is arranged in front of the cooling nozzle that sprays the mist. A rail weld cooling device for cooling the rail weld where the top surface of the rail is ground after welding.
A plurality of cooling nozzles that spray mist from both sides of the abdomen excluding the parietal surface of the rail so that mist does not get on the parietal surface of the rail.
A nozzle jig arranged on the rail for arranging the plurality of cooling nozzles toward the abdomen of the rail, and
Fixing means for fixing the nozzle jig on the rail and
A cooling liquid supply means for supplying a cooling liquid for mist spraying to the plurality of cooling nozzles, and
A gas supply means for supplying a gas for mist spraying to the plurality of cooling nozzles,
A cooling device for rail welds, which is characterized by being equipped with. The cooling device for a rail welded portion according to claim 6, wherein the weld is a thermite weld. The cooling device for a rail welded portion according to claim 6 or 7, wherein the nozzle jig is provided with a space capable of grinding the crown surface of the rail during mist spraying. The cooling device for a rail welded portion according to any one of claims 6 to 8, wherein the plurality of cooling nozzles are four or more. The cooling device for a rail welded portion according to any one of claims 6 to 9, wherein the spray angle of the cooling nozzle is 20 ° or more and less than 110 °. The cooling device for a rail welded portion according to any one of claims 6 to 10, further comprising a shield provided in front of the cooling nozzle to block a part of the mist.

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