A railway wheel cooling device, cooling method and preparation method

Abstract

The present invention discloses a railway wheel cooling device, a cooling method and a preparation method, belonging to the technical field of railway wheels. The device includes a quenching table and a plurality of spray guns evenly arranged along its circumferential direction. The spray gun includes a water outlet panel and an inlet branch pipe. The water outlet panel is provided with large spray holes and small spray holes with different diameters. Among them, the small spray holes are individually controlled for water outlet by a branch pipe, and the large spray holes are divided into upper and lower parts, and the water outlet is controlled by different branch pipes respectively. It can conveniently adjust the strength of the cooling water sprayed towards the wheel, and improve the cooling uniformity of the wheel rim in the radial and axial directions. The cooling method uses the above cooling device to perform heat treatment cooling on the wheel during the preparation of the wheel, effectively strengthening the hardness uniformity of the wheel rim and improving the service performance of the wheel. The preparation method uses the above cooling method to perform heat treatment cooling on the wheel during the preparation, and can prepare a wheel with high hardness uniformity of the wheel rim.

Description

Technical Field

[0001] The present invention belongs to the technical field of railway wheels, and more specifically, relates to a railway wheel cooling device, a cooling method and a preparation method. Background Art

[0002] Currently, during the preparation of railway wheels at home and abroad, continuous low-pressure and large-flow forced water spraying on the tread surface is a common heat treatment cooling method. However, in this cooling method, the near-surface layer of the tread is in direct contact with the cooling medium, resulting in a very large instantaneous temperature drop. The heat inside the rim can only be taken away by the cooling medium after being conducted to the near-surface layer of the tread through heat conduction, and the cooling speed is significantly lower than that of the near-surface layer of the tread. This significant difference in cooling speed between the near-surface layer of the tread and the inside of the rim not only causes an abnormal non-pearlite structure to form in the near-surface layer of the tread, but also leads to insufficient cooling capacity inside the rim, resulting in uneven cooling along the radial direction of the entire cross-section of the rim, and the rim performance is affected. In response to this, corresponding measures have also been taken in the existing cooling processes for iron wheels.

[0003] For example, the patent document with the Chinese patent application number: CN200810020421.5 and the publication date: September 24, 2008 discloses a heat treatment method for the surface of the rim of a high-carbon steel train wheel. During the cooling process, first, a small-flow water stream is used to spray and cool the tread surface of the train wheel for a short time, and then a large-flow water stream is used to perform long-term forced water spraying on the tread surface. The invention also discloses a heat treatment device for implementing the above method, in which the water inlet ring pipe is divided into a large-flow water inlet ring pipe and a small-flow water inlet ring pipe. The large-flow water inlet ring pipe is connected to a plurality of large-flow nozzles; the small-flow water inlet ring pipe is connected to a plurality of small-flow nozzles.

[0004] Another example is the patent document with the Chinese patent application number: CN201910358140.9 and the publication date: July 26, 2019, which discloses a heat treatment cooling process for railway wheels, belonging to the technical field of heat treatment cooling of railway wheels. The method steps include: first, heating the wheel as a whole to complete austenitization; then transporting it to a quenching table, keeping the wheel in a rotating state, and spraying the tread surface of the wheel with a pressure-step-increasing aerosol two-phase flow; then putting the wheel as a whole into a tempering furnace for heat preservation, and finally taking it out for air cooling; the pressure-step-increasing aerosol two-phase flow spraying on the tread surface of the wheel includes three stages, controlling the wheel rotation speeds v1>v2>v3, water pressures P1<P2<P3, and quenching cooling times T1<T2<T3 in the three stages; the number of nozzles distributed at equal intervals along the circumferential direction of the wheel started in the three stages is M, 2M, and 3M respectively.

[0005] In view of the excessive difference in the cooling rates between the near-surface layer of the wheel tread and the inside of the rim during the heat treatment cooling process of the wheel, which results in abnormal structures appearing in the near-surface layer of the tread and uneven radial cooling of the rim, both of the above two solutions adopt the method of first performing small-flow jet cooling on the wheel tread and then large-flow jet cooling, so that the cooling rate regions from the wheel tread to the inside of the rim are uniform, reducing the probability of abnormal structures appearing in the near-surface layer of the tread. However, both of these two solutions only consider the uniformity of the cooling rate of the rim along the radial direction and do not consider the cooling uniformity of the rim in the axial direction. In the actual heat treatment process, due to the action of gravity, the cooling medium accumulates at the rim at the lower end of the wheel, resulting in the cooling rate at the lower-end rim being significantly greater than that at the upper-end rim, thus affecting the cooling uniformity of the rim in the axial direction and reducing the performance of the rim.

[0006] In addition, the existing railway wheel cooling treatment devices in the prior art also do not take corresponding measures for the cooling uniformity of the wheel rim in the axial direction. For example, the patent document with the Chinese patent application number: CN201810189670.0 and the publication date: July 31, 2018 discloses a special combined nozzle for wheel quenching, which includes a first set of nozzles and a second set of nozzles. The first set of nozzles includes a nozzle pot cavity and a nozzle water spray panel provided on the nozzle pot cavity. The nozzle pot cavity is provided with a water inlet for the first set of nozzles, and the nozzle water spray panel is provided with water outlet holes for the first set of nozzles. The second set of nozzles is installed on the nozzle water spray panel of the first set of nozzles, and the water inlet pipe of the second set of nozzles is arranged in the nozzle pot cavity of the first set of nozzles. The installation of the second set of nozzles is reasonable, the adjustment of the two sets of nozzles is standardized, the adjustment operation is simplified, the adjustment intensity of the nozzles is reduced, the adjustment time is greatly shortened, and the production efficiency of the heat treatment production line is greatly improved. However, the second set of small-flow nozzles of this solution is integrated on the water spray panel of the first set of large-flow nozzles and protrudes a certain length. Limited by the spraying range, it cannot fully cover the entire tread area, directly affecting the uniformity of the hardness of the rim cross-section, and it cannot solve the problem of the cooling uniformity of the rim in the axial direction mentioned above.

[0007] Since improving the cooling uniformity of the railway wheel rim can improve the hardness uniformity of the rim, which is beneficial to improving the service performance of the wheel, especially preventing or slowing down the occurrence of problems such as out-of-roundness (polygon) and eccentric wear of the wheel and improving the wear uniformity during the entire life cycle. Therefore, to solve the deficiencies of the prior art and manufacture railway wheels with high hardness uniformity, it is particularly necessary to provide a preparation method and device. Summary of the Invention

[0008] 1. Problems to be Solved

[0009] In view of the problem that in the preparation of iron wheel wheels, it is difficult for existing heat treatment cooling devices to ensure the cooling uniformity at the rim, which affects the service performance of the wheels, the present invention provides a railway wheel cooling device, which can conveniently adjust the intensity of the cooling water sprayed onto the wheels, improve the cooling uniformity of the wheel rims in the radial and axial directions, and prepare wheels with higher service performance.

[0010] The present invention also provides a method for cooling an iron wheel wheel. When preparing the wheel, heat treatment cooling is carried out on the wheel by using the above cooling device, effectively strengthening the hardness uniformity of the wheel rim and improving the service performance of the wheel.

[0011] The present invention also provides a method for preparing an iron wheel wheel. When preparing the wheel, heat treatment cooling is carried out on the wheel by using the above cooling method, and a wheel with high hardness uniformity of the rim can be prepared.

[0012] 2. Technical solution

[0013] To solve the above problems, the present invention adopts the following technical solutions.

[0014] A railway wheel cooling device includes a quenching table and a plurality of spray guns evenly arranged along its circumference. The spray gun includes a water outlet panel and an inlet branch pipe. At least one row of large spray holes arranged from top to bottom is provided on the water outlet panel, and at least one row of small spray holes arranged from top to bottom is provided on one side of the large spray holes. The inlet branch pipe includes two large spray hole branch pipes and one small spray hole branch pipe. One of the large spray hole branch pipes is connected to the large spray holes in the upper part of the water outlet panel, and the other large spray hole branch pipe is connected to the large spray holes in the lower part of the water outlet panel. The small spray hole branch pipe is connected to the small spray holes.

[0015] As a further improvement of the cooling device, a plurality of convex bodies extending from top to bottom are provided on the water outlet panel, and both the large spray holes and the small spray holes are arranged on one side surface of the convex body.

[0016] As a further improvement of the cooling device, the included angle between the side surface of the convex body where the large spray holes and the small spray holes are located and the water outlet panel is 40 - 50°.

[0017] As a further improvement of the cooling device, it also includes two large-diameter ring pipes and one small-diameter ring pipe. One of the large-diameter ring pipes is respectively connected to each large spray hole branch pipe communicating with the large spray holes in the upper part of the water outlet panel, the other large-diameter ring pipe is respectively connected to each large spray hole branch pipe communicating with the large spray holes in the lower part of the water outlet panel, and the small-diameter ring pipe is respectively connected to each small spray hole branch pipe.

[0018] As a further improvement of the cooling device, the diameter of the large spray holes is 4 - 5 mm, and the diameter of the small spray holes is 1.5 - 2 mm.

[0019] A method for cooling railway wheels, which uses the above-mentioned cooling device for iron wheels to cool the wheels during the heat treatment stage, includes the following steps:

[0020] I. Preparation stage

[0021] Transport the wheels to be cooled to the quenching table, with the side of the wheel facing up. Start the quenching table to make the wheels rotate;

[0022] II. Small-flow injection stage

[0023] Start the small orifice branch pipe to inject water onto the wheels. The injection time is 60 - 210 s, and the water pressure is P0;

[0024] III. Large-flow injection stage

[0025] Stop the small orifice branch pipe and start the large orifice branch pipe to inject water onto the wheels until the transition part between the rim and the spoke of the wheels darkens, then stop the injection. Among them, the water pressure of the large orifice branch pipe connecting to the upper large orifices of the water outlet panel is P1, and the water pressure of the large orifice branch pipe connecting to the lower large orifices of the water outlet panel is P2;

[0026] Among them, P1 > P2 > P0.

[0027] As a further improvement of the cooling method, in the above steps II and III, P0 is 0.05 - 0.15 MPa, P1 is 0.35 - 0.45 MPa, and P2 is 0.3 - 0.4 MPa.

[0028] As a further improvement of the cooling method, in the above step II, the water outlet speed of the small orifices is 3 - 5 m / s, and the water output of a single spray gun is 4 - 7 m 3 / h; in the above step III, the water outlet speed of the large orifices is 7 - 12 m / s, and the water output of a single spray gun is 20 - 22 m 3 / h.

[0029] As a further improvement of the cooling method, the carbon content of the steel of the wheels is 0.50 - 0.75%, and the wheel diameter is 840 - 1250 mm.

[0030] A preparation method for iron wheels, which includes blank cutting, heating, forming, heat treatment, and finishing. Among them, the heat treatment includes heating, cooling, and tempering, and the cooling step uses the above-mentioned method for cooling railway wheels.

[0031] 3. Beneficial effects

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) A railway wheel cooling device of the present invention is provided with two kinds of spray holes with different diameters arranged from top to bottom on the water outlet panel, and water is supplied through water inlet branch pipes of different sizes, so that it can conveniently control the spray gun to adopt a water spraying cooling method of first weak and then strong for the wheel, improving the cooling uniformity of the wheel rim in the radial direction of the wheel. In particular, this device can also separately control the water pressure and water outlet speed of the large spray holes in the upper and lower parts of the water outlet panel, adjust the water spray amount of the spray gun on the wheel rim in the axial direction of the wheel, strengthen the cooling uniformity of the wheel rim in the axial direction of the wheel, that is, this device can conveniently adjust the cooling speed of the wheel rim in the axial and radial directions of the wheel, strengthen the hardness uniformity of each position of the wheel rim, and improve its service performance;

[0034] (2) A railway wheel cooling device of the present invention is provided with multiple convex bodies on the water outlet panel, and then the spray holes are arranged on the side surfaces of the convex bodies. By setting the angle of the side surface relative to the water outlet panel, the spraying angle of the spray holes on the wheel can be set. By replacing the water outlet panel with different angles, the spraying angle most suitable for the prepared wheel can be found, improving the cooling effect;

[0035] (3) A railway wheel cooling device of the present invention is provided with three ring pipes respectively connected to the water inlet branch pipes on each spray gun, so that the water outlet amount of multiple spray guns can be adjusted only by adjusting the water inlet amount of each ring pipe. On the one hand, the adjustment is convenient, and on the other hand, the water outlet amount of each spray gun can also be ensured to be consistent, improving the cooling uniformity of the wheel tread;

[0036] (4) A railway wheel cooling device of the present invention can realize full-coverage spraying of the entire tread between the wheel rim vertex and the tread inflection point of the wheel, ensuring the stability and uniformity of the cooling effect, significantly improving the hardness uniformity of the wheel rim along the circumferential direction, and preventing or slowing down the occurrence of the wheel polygon problem;

[0037] (5) A railway wheel cooling method of the present invention adopts the above-mentioned railway wheel cooling device. By adopting a cooling method of first weak and then strong for the wheel, the cooling uniformity of the wheel rim in the radial direction of the wheel can be improved, significantly reducing or avoiding the generation of abnormal structures in the near-surface layer of the wheel tread, optimizing the overall cross-section structure of the wheel rim. It can not only reduce or eliminate subsequent cutting processing, improve the metal utilization rate, but also significantly reduce the hardness gradient of the wheel rim in the radial direction, improving the wear uniformity during the use of the wheel;

[0038] (6) A railway wheel cooling method of the present invention can significantly reduce or avoid the inconsistent cooling speed of the wheel rim in the axial direction of the wheel caused by the accumulation of cooling water at the lower part of the wheel rim due to the action of gravity by adjusting the pressure of the sprayed water flow on the upper and lower ends of the wheel rim of the wheel, thereby improving the cooling uniformity of the wheel rim in the axial direction of the wheel, reducing the hardness gradient of the wheel rim in the axial direction, and reducing the problem of wheel flange wear;

[0039] (7) The preparation method of an iron wheel of the present invention uses the above-mentioned cooling method for railway wheels to perform heat treatment operations on the wheels, and can prepare wheels with uniform rim hardness, reduce the problem of uneven wear of the wheel flange, reduce the probability of the wheel becoming polygonal, and improve the service life of the wheel. Description of the Drawings

[0040] Figure 1 It is a top view of the cooling device of the present invention;

[0041] Figure 2 It is a schematic structural diagram of the water outlet panel of the present invention;

[0042] Figure 3 It is Figure 2 a partial enlarged view at the elliptical dotted line in

[0043] Figure 4 a working schematic diagram of the spray gun spraying water on the tread;

[0044] Figure 5 a schematic diagram of the grid hardness test of the wheel rim cross-section;

[0045] Figure 6 It is the circumferential distribution of the wheel rim cross-section hardness of the wheel ① in Experiment 1;

[0046] Figure 7 It is the circumferential distribution of the wheel rim cross-section hardness of the wheel ② in Experiment 1;

[0047] Figure 8 It is the circumferential distribution of the wheel rim cross-section hardness of the wheel ① in Experiment 2;

[0048] Figure 9 It is the circumferential distribution of the wheel rim cross-section hardness of the wheel ② in Experiment 2;

[0049] Figure 10 It is the circumferential distribution of the wheel rim cross-section hardness of the wheel ① in Experiment 3;

[0050] Figure 11 It is the circumferential distribution of the wheel rim cross-section hardness of the wheel ② in Experiment 3;

[0051] In the figure: 1, quenching table; 2, spray gun; 21, water outlet panel; 22, large spray hole; 23, small spray hole; 24, large spray hole branch pipe; 25, small spray hole branch pipe; 26, convex body; 3, wheel rim; 31, tread; 32, wheel flange; 33, wheel flange throat; 34, tread inflection point. Detailed Embodiments

[0052] The present invention will be further described below in conjunction with specific embodiments and the drawings.

[0053] Embodiment 1

[0054] A railway wheel cooling device is used to cool the wheels during the heat treatment stage in the preparation of railway wheels. As Figure 1 shown, the device includes a quenching table 1 and a spray gun 2. The quenching table 1 is a rotatable disc structure, which is controlled by a motor to rotate. There are multiple spray guns 2, which are evenly distributed along the circumference of the quenching table 1. The specific number is determined according to the diameter of the wheel. In this embodiment, there are 6 spray guns. When cooling the wheel, the side of the wheel is placed on the quenching table 1, and the water spraying direction of the spray gun 2 is directly facing the tread of the wheel to spray and cool the tread of the wheel. The specific structure of the spray gun 2 will be described in detail below.

[0055] As Figures 1 to 3 shown, the spray gun 2 includes a water outlet panel 21 and a water inlet branch pipe connected to the water outlet panel 21. The water outlet panel 21 has at least one row of large spray holes 22 arranged at equal intervals from top to bottom. On one side of the large spray holes 22, there is at least one row of small spray holes 23 arranged at equal intervals from top to bottom. The water inlet branch pipe includes two large spray hole branch pipes 24 and one small spray hole branch pipe 25. Among them, the water inlets connected to the two large spray hole branch pipes 24 are symmetrically installed at the upper and lower ends of the water outlet panel 21. One water inlet communicates with the large spray holes 22 in the upper half of the water outlet panel 21, and the other water inlet communicates with the large spray holes 22 in the lower half of the water outlet panel 21. The water inlet connected to the small spray hole branch pipe 25 is arranged on one side of the two large spray hole branch pipes 24, and its height is in the middle of the two large spray hole branch pipes 24. This water inlet communicates with all the small spray holes 25. Specifically, there can be various connection methods between the water inlet and the spray holes, such as arranging a pipe connecting the water inlet for each spray hole, or arranging cavities corresponding to the large spray holes 22 in the upper half, the large spray holes 22 in the lower half, and the small spray holes 23 in the water outlet panel 21, and each water inlet communicates with a cavity respectively.

[0056] In order to adjust the water spraying angle of the spray holes and improve the cooling effect on the wheels. In this embodiment, multiple convex bodies 26 extending from top to bottom are provided on the water outlet panel 21. The convex bodies 26 are in the shape of triangular prisms. The spray holes are arranged on one side surface of the convex bodies 26. During operation, the water spraying panel 21 is facing the tread of the wheel. By setting the angle between the side surface of the convex body 26 where the spray holes are located and the water outlet panel 21, the angle at which the water flow sprays towards the wheel can be determined. For wheels with different thicknesses and diameters, the water flow spraying angle can be adjusted by replacing different water outlet panels 21 to find the spraying angle with the best cooling effect. Usually, the angle between the water spraying panel 21 and the side surface where the spray holes are located is preferably maintained at 40 - 50°, and in this embodiment, it is taken as 45°.

[0057] In this embodiment, eight convex bodies are successively arranged on the water outlet panel 21 from left to right. Among them, six large spray holes 22 are arranged in six rows on the six convex bodies 26 on the left side, and the positions between adjacent two rows of large spray holes 22 are arranged staggeredly to ensure full coverage spraying on the tread of the wheel. On the two convex bodies 26 on the right side, two rows of small spray holes 23 are arranged, and the positions between the two rows of small spray holes 23 are arranged staggeredly to ensure full coverage spraying on the tread of the wheel. The uppermost large spray hole 22 and the uppermost small spray hole 23 are at the same height, and the lowermost large spray hole 22 and the lowermost small spray hole 23 are also at the same height, so that only by adjusting the large spray hole 22 or the small spray hole 23 that can spray to the uppermost and lowermost ends of the wheel tread, it can be ensured that both can achieve full coverage spraying on the tread. As Figure 4 shown, it is a working schematic diagram of the spray gun 2 for full coverage spraying on the tread 31 of the wheel rim 3. The inner side of the wheel in this working schematic diagram is placed on the quenching table 1 with the upper side facing up. The height of the water flow sprayed from the uppermost spray hole of the water outlet panel 21 is equal to the vertex of the wheel flange 32, and the lowermost spray hole is at the same height as the tread inflection point 34.

[0058] The diameter of the large spray hole 22 is 4 - 5 mm, and the diameter of the small spray hole 23 is 1.5 - 2 mm. This diameter range is a range with better cooling effect selected to cooperate with relevant cooling processes. In this embodiment, the diameter of the large spray hole 22 is taken as 4.5 mm, and the diameter of the small spray hole 23 is taken as 1.7 mm.

[0059] In addition, in order to ensure the same water volume of each spray gun 2 and make the cooling of each part of the wheel uniform, the device is also provided with two large-diameter ring pipes and one small-diameter ring pipe, and the ring pipes are arranged around the quenching table 1. Among them, one large-diameter ring pipe is respectively connected to each large spray hole branch pipe 24 that communicates with the upper large spray holes 22 of the water outlet panel 21, and the other large-diameter ring pipe is respectively connected to each large spray hole branch pipe 24 that communicates with the lower large spray holes 22 of the water outlet panel 21. The small-diameter ring pipe is respectively connected to each small spray hole branch pipe 25. Therefore, by only adjusting the water inflow of each ring pipe, the water inflow of the spray hole branch pipe connected to this ring pipe can be adjusted, thereby adjusting the water outflow of the corresponding part of the spray holes, and the control is extremely convenient. And because the spray holes of the corresponding parts of multiple water outlet panels 21 are supplied with water by the same ring pipe, it can well ensure the same water outflow of the corresponding parts of each spray gun 2 and improve the cooling uniformity of the wheel.

[0060] In summary, a railway wheel cooling device in this embodiment can conveniently adjust the strength of the cooling water sprayed towards the wheel. With the corresponding cooling method, it can effectively improve the cooling uniformity of the wheel rim in the radial and axial directions and prepare wheels with higher service performance.

[0061] Embodiment 2

[0062] A railway wheel cooling method, which uses a railway wheel cooling device of Embodiment 1 to cool the wheel to be cooled, includes the following steps:

[0063] I. Preparation stage

[0064] Transport the wheel to be cooled in the heat treatment stage to the quenching table 1, with the side of the wheel facing upwards and the tread of the wheel facing the water outlet panel 21 of the spray gun 2. Then, start the quenching table 1 to make the wheel rotate.

[0065] II. Small-flow injection stage

[0066] Start the small orifice branch pipe 25 to spray the wheel for 60 - 210 s, with the water pressure being P0. In this step, P0 is 0.05 - 0.15 Mpa. The specific spraying time depends on the wheel diameter and the chemical composition of the wheel steel. When a complete fine pearlite + a small amount of ferrite, i.e., F - P tissue transformation occurs within a certain depth near the surface layer of the tread, stop spraying. At this time, the metal temperature inside the rim is still above the Ac3 temperature and no cooling transformation has occurred yet.

[0067] III. Large-flow injection stage

[0068] Stop the small orifice branch pipe 25 and start the large orifice branch pipe 24 to spray the wheel until the transition part between the rim and the spoke of the wheel darkens. After achieving a complete fine pearlite + a small amount of ferrite tissue transformation, stop spraying. Among them, the water pressure of the large orifice branch pipe 24 connected to the upper large orifice 22 of the water outlet panel 21 is P1, and the water pressure of the large orifice branch pipe 24 connected to the lower large orifice 22 of the water outlet panel 21 is P2. In this step, P1 is 0.35 - 0.45 MPa, and P2 is 0.3 - 0.4 Mpa.

[0069] During spraying, P1 > P2 > P0. In Step II, the water outlet speed of the small orifice 23 is 3 - 5 m / s, and the water output of a single spray gun 2 is 4 - 7 m 3 / h; in Step III, the water outlet speed of the large orifice 22 is 7 - 12 m / s, and the water output of a single spray gun 2 is 20 - 22 m 3 / h. This numerical range is a preferred numerical range with better cooling effect for the wheel, especially for wheels with a carbon content of 0.50 - 0.75% in steel and a wheel diameter of 840 - 1250 mm, the cooling effect is excellent.

[0070] This method adopts a water spraying and cooling method that starts with weak cooling and then strengthens, which can reduce the difference in cooling rates between the near-surface layer of the tread and the interior of the rim, improve the cooling uniformity of the rim in the radial direction of the wheel, significantly reduce or avoid the generation of abnormal structures in the near-surface layer of the wheel tread, optimize the organizational structure of the entire cross-section of the rim. This can not only reduce or eliminate subsequent machining, improve metal utilization rate, but also significantly reduce the hardness gradient of the rim along the radial direction and improve the wear uniformity during wheel use.

[0071] In addition, when spraying the wheel tread, under the action of gravity, the cooling water will flow to and accumulate at the lower end of the rim. The contact time and contact area between the lower end of the rim and the cooling water are both greater than those of the upper end of the rim, resulting in a difference in cooling rates between the upper and lower parts of the rim, that is, uneven cooling in the axial direction of the wheel, damaging the hardness uniformity of the rim in the axial direction of the wheel, and thus affecting its service performance. Especially at Figure 4 the throat 33 of the wheel flange as shown, due to the relatively small contact area between this part and the sprayed water flow, the difference in cooling rates between this part and the lower end of the rim is particularly obvious. In the large-flow spraying stage of this embodiment, by adjusting the water pressure of the two large spray eye branches 24, the water pressure of the large spray eyes 22 in the upper half of the water outlet panel 21 is made greater than that of the large spray eyes 22 in the lower half, significantly reducing or avoiding the situation of inconsistent cooling rates of the rim in the axial direction of the wheel caused by the accumulation of cooling water at the lower part of the rim due to gravity, improving the cooling uniformity of the rim in the axial direction of the wheel, reducing the hardness gradient of the rim along the axial direction, and reducing the problem of uneven wear of the wheel flange.

[0072] In particular, when this cooling method is combined with a railway wheel cooling device in Embodiment 1 to cool the wheel, the water pressure and water volume of multiple spray guns 2 can be adjusted simultaneously only by adjusting the water inflow and water pressure of the three ring pipes. The adjustment is extremely convenient, and the water volume and water pressure of each spray gun 2 are ensured to be consistent, improving the cooling uniformity of the wheel tread.

[0073] Therefore, when this cooling device and cooling method are used in combination, it can be conveniently adjusted when cooling the wheel, making the rim cooled evenly in both the axial and radial directions of the wheel, improving the hardness uniformity of the rim, and preparing railway wheels with excellent service performance.

[0074] To further illustrate and embody the improvements of the present invention, the data and result analysis of several comparative experiments are given below.

[0075] Experiment 1

[0076] ① Prepare a to-be-cooled blank wheel made of steel with a carbon content of 0.50 wt% and a wheel diameter of 1250 mm, place it on the quenching table 1 with its inner side facing up, control the distance between the water outlet panel 21 and the wheel tread to be 120 mm, start the control unit of the quenching table 1, and control the quenching table 1 to rotate at 90 r / min.

[0077] First, start the small nozzles 23 to spray the wheel tread surface. Control the water pressure of the small nozzle branch pipe 25 to be 0.05 MPa, the water outlet speed of the small nozzles 23 to be 3 m / s, and the spraying and cooling time to be 60 s, so that a complete fine pearlite + a small amount of ferrite (i.e., F-P) structure transformation occurs within 10 mm of the near-surface layer of the tread surface. However, at this time, the metal temperature inside the rim is still above the Ac3 temperature and no cooling transformation has occurred yet. Then, immediately start the large nozzles 22 to spray the wheel tread surface. Control the water pressure of the large nozzle branch pipe 24 connected to the upper half of the large nozzles 22 to be 0.35 Mpa, and the water outlet speed of the large nozzles 22 to be 8 m / s. Control the water pressure of the large nozzle branch pipe 24 connected to the lower half of the large nozzles 22 to be 0.3 Mpa, and the water outlet speed of the large nozzles 22 to be 7 m / s. Stop spraying after the transition part between the rim and the spoke becomes dark. Then, temper and finish-machine the cooled wheel to obtain the finished wheel.

[0078] ② Prepare a to-be-cooled blank wheel made of steel with a carbon content of 0.50 wt% and a wheel diameter of 1250 mm. Place it on the quenching table 1 with its inner side facing up. Control the distance between the water outlet panel 21 and the wheel tread surface to be 120 mm. Start the control unit of the quenching table 1 and control the quenching table 1 to rotate at 90 r / min.

[0079] Start the large nozzles 22 to spray the wheel tread surface. The water pressure of both large nozzle branch pipes 24 is 0.3 MPa, and the water outlet speed of the large nozzles 22 is 7 m / s. Stop spraying after the transition part between the rim and the spoke becomes dark. Then, temper and finish-machine the cooled wheel to obtain the finished wheel.

[0080] As Figure 5 shown, cut a quarter of the rim of the finished wheels prepared in ① and ② of Experiment 1 circumferentially. Take a section hardness block every 10° circumferentially from one end to the other end of the edge for grid hardness testing. The results are shown in Table 1 below.

[0081] Table 1 Cross-section grid hardness of ① and ② (5 / 750 HBW)

[0082]

[0083] Analyze the maximum value, minimum value, and average value of the hardness along the radial and axial directions of the rim. The results show that: at the parts of the rim with the same distance from the tread surface, the hardness gradient in ① is within 10 HB, while the hardness gradient in ② is above 20 HB. That is, the hardness uniformity of the rim in ① along the axial direction of the wheel is significantly better than that of the rim in ② along the axial direction of the wheel; at the rim parts with the same taken angle, the hardness gradient in ① is within 10 HB, while the hardness gradient in ② is above 20 HB. That is, the hardness uniformity of the rim in ① along the radial direction of the wheel is significantly better than that of the rim in ② along the radial direction of the wheel.

[0084] Then, take cross-sectional blocks at different positions under the tread in the circumferential range of 0 to 90° for hardness analysis. As Figure 6 and Figure 7 shown, the hardness uniformity of the wheel rim of ① along the circumference is significantly better than that of the wheel rim of ② along the circumference.

[0085] Experiment 2

[0086] ① Prepare a to-be-cooled blank wheel made of steel with a carbon content of 0.62 wt% and a wheel diameter of 840 mm. Place it on the quenching table 1 with its inner side facing up. Control the distance between the water outlet panel 21 and the wheel tread to be 110 mm. Start the control unit of the quenching table 1 and control the quenching table 1 to rotate at 50 r / min.

[0087] First, start the small spray holes 23 to spray the wheel tread. Control the water pressure of the small spray hole branch pipe 25 to be 0.1 MPa, the water outlet speed of the small spray holes 23 to be 4 m / s, and the spraying and cooling time to be 140 s, so that a complete fine pearlite + a small amount of ferrite (i.e., F - P) tissue transformation occurs within 15 mm of the near-surface layer of the tread. However, at this time, the metal temperature inside the wheel rim is still above the Ac3 temperature and no cooling transformation has occurred yet. Then, immediately start the large spray holes 22 to spray the wheel tread. Control the water pressure of the large spray hole branch pipe 24 connected to the upper half of the large spray holes 22 to be 0.4 Mpa, and the water outlet speed of the large spray holes 22 to be 10 m / s. Control the water pressure of the large spray hole branch pipe 24 connected to the lower half of the large spray holes 22 to be 0.35 Mpa, and the water outlet speed of the large spray holes 22 to be 9 m / s. Stop spraying after the transition part between the wheel rim and the wheel spoke becomes dark. Then, temper and finish the cooled wheel to obtain a finished wheel.

[0088] ② Prepare a to-be-cooled blank wheel made of steel with a carbon content of 0.62 wt% and a wheel diameter of 840 mm. Place it on the quenching table 1 with its inner side facing up. Control the distance between the water outlet panel 21 and the wheel tread to be 110 mm. Start the control unit of the quenching table 1 and control the quenching table 1 to rotate at 50 r / min.

[0089] Start the large spray holes 22 to spray the wheel tread. The water pressure of both large spray hole branch pipes 24 is 0.35 MPa, and the water outlet speed of the large spray holes 22 is 9 m / s. Stop spraying after the transition part between the wheel rim and the wheel spoke becomes dark. Then, temper and finish the cooled wheel to obtain a finished wheel.

[0090] As Figure 5 shown, take a quarter of the wheel rim of the finished wheels prepared in ① and ② of Experiment 1 along the circumference. Take a section hardness block every 10° along the circumference from one end to the other end of the edge for grid hardness testing. The results are shown in Table 2 below.

[0091] Cross-sectional grid hardness of Tables 2① and ② (5 / 750HBW)

[0092]

[0093] Analyze the maximum, minimum, and average hardness values along the radial and axial directions of the rim. The results show that: at the positions where the distance from the rim to the tread surface is the same, the hardness gradient in ① is within 15HB, while the hardness gradient in ② is above 25HB. That is, the hardness uniformity of the rim in ① along the axial direction of the wheel is significantly better than that of the rim in ② along the axial direction of the wheel; at the rim positions with the same angle taken, the hardness gradient in ① is within 15HB, while the hardness gradient in ② is above 25HB. That is, the hardness uniformity of the rim in ① along the radial direction of the wheel is significantly better than that of the rim in ② along the radial direction of the wheel.

[0094] Then, take cross-sectional blocks at different positions under the tread surface along the circumferential direction from 0 to 90° for hardness analysis. As Figure 8 and Figure 9 shown, the hardness uniformity of the wheel rim in ① along the circumferential direction is significantly better than that of the wheel rim in ② along the circumferential direction.

[0095] Experiment 3

[0096] ① Prepare a to-be-cooled blank wheel made of steel with a carbon content of 0.75wt% and a wheel diameter of 950mm. Place it on the quenching table 1 with its inner side facing up. Control the distance between the water outlet panel 21 and the wheel tread to be 100mm. Start the control unit of the quenching table 1 and control the quenching table 1 to rotate at 70r / min.

[0097] First, start the small spray holes 23 to spray the wheel tread. Control the water pressure of the small spray hole branch pipe 25 to be 0.15MPa, the water outlet speed of the small spray holes 23 to be 5m / s, and the spraying and cooling time to be 210s, so that a complete fine pearlite + a small amount of ferrite (i.e., F - P) structure transformation occurs within 20mm of the near-surface layer of the tread. However, at this time, the metal temperature inside the rim is still above the Ac3 temperature and no cooling transformation has occurred yet. Then, immediately start the large spray holes 22 to spray the wheel tread. Control the water pressure of the large spray hole branch pipe 24 connected to the upper half of the large spray holes 22 to be 0.45Mpa, and the water outlet speed of the large spray holes 22 to be 12m / s. Control the water pressure of the large spray hole branch pipe 24 connected to the lower half of the large spray holes 22 to be 0.4Mpa, and the water outlet speed of the large spray holes 22 to be 11m / s. Stop spraying after the transition area between the rim and the spoke becomes dark. Then, temper and finish the cooled wheel to obtain the finished wheel.

[0098] ② Prepare a blank wheel to be cooled with a carbon content of 0.75 wt% in steel and a wheel diameter of 950 mm, place it on the quenching table 1 with its inner side facing up, control the distance between the water outlet panel 21 and the wheel tread to be 100 mm, start the control unit of the quenching table 1, and control the quenching table 1 to rotate at 70 r / min.

[0099] Start the large spray holes 22 to spray the wheel tread. The water pressure of both large spray hole branch pipes 24 is 0.4 MPa, and the water outlet speed of the large spray holes 22 is 11 m / s. Stop spraying after the transition between the rim and the spoke becomes dark. Then temper and finish machine the cooled wheel to obtain the finished wheel.

[0100] As Figure 5 shown, cut one-fourth of the rim of the finished wheels prepared in ① and ② of Experiment 1 circumferentially, and take a section hardness block every 10° circumferentially from one end to the other end of the edge for grid hardness testing. The results are shown in Table 3 below.

[0101] Table 3 Section grid hardness of ① and ② (5 / 750 HBW)

[0102]

[0103] Analyze the maximum, minimum, and average values of the hardness along the radial and axial directions of the rim. The results show that at the parts of the rim with the same distance from the tread, the hardness gradients in ① are all within 17 HB, while those in ② are all above 30 HB. That is, the hardness uniformity of the rim in ① along the axial direction of the wheel is significantly better than that of the rim in ② along the axial direction of the wheel; at the rim parts with the same angle taken, the hardness gradients in ① are all within 17 HB, while those in ② are all above 30 HB. That is, the hardness uniformity of the rim in ① along the radial direction of the wheel is significantly better than that of the rim in ② along the radial direction of the wheel.

[0104] Then take the cross-section blocks at different positions under the tread from 0 to 90° circumferentially for hardness analysis. As Figure 10 and Figure 11 shown, the hardness uniformity of the wheel rim in ① along the circumferential direction is significantly better than that of the wheel rim in ② along the circumferential direction.

[0105] In summary, it can be concluded from Experiments 1, 2, and 3 that a railway wheel cooling method of this embodiment has obvious improvements in the hardness uniformity of the rim along the axial, radial, and circumferential directions of the wheel compared with the existing continuous large-flow low-pressure spray cooling method, effectively improving the service performance of the wheel.

[0106] Example 3

[0107] A method for preparing railway wheels includes blank cutting, heating, forming, heat treatment and finishing. Among them, the heat treatment includes heating, cooling and tempering. Except for the cooling step, the remaining steps are existing technologies adopted in conventional process production and will not be described in detail here. The cooling step adopts a railway wheel cooling method of Embodiment 2, which can greatly improve the hardness uniformity of the rim of the prepared railway wheels, thereby improving the service performance of the wheels.

[0108] The examples described in the present invention are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various deformations and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope of the present invention.

Claims

1. A railway wheel cooling method, using a railway wheel cooling device, the cooling device comprising a quenching table (1) and a plurality of spray guns (2) evenly arranged along its circumferential direction, characterized in that: The spray gun (2) includes a water outlet panel (21) and an inlet branch pipe; at least one row of large spray holes (22) arranged from top to bottom is provided on the water outlet panel (21), and at least one row of small spray holes (23) arranged from top to bottom is provided on one side of the large spray holes (22); the inlet branch pipe includes two large spray hole branch pipes (24) and one small spray hole branch pipe (25), wherein one large spray hole branch pipe (24) is connected to the large spray holes (22) in the upper part of the water outlet panel (21), the other large spray hole branch pipe (24) is connected to the large spray holes (22) in the lower part of the water outlet panel (21), and the small spray hole branch pipe (25) is connected to the small spray holes (23); The cooling method includes the following steps: I. Preparation stage Transport the wheel to be cooled to the quenching table (1), make the side of the wheel face upward, start the quenching table (1), and make the wheel in a rotating state; II. Small flow rate spraying stage Start the small spray hole branch pipe (25) to spray the wheel, the spraying time is 60 - 210 s, the water pressure is P0, in this step, the water outlet speed of the small spray holes (23) is 3 - 5 m / s, and the water output of a single spray gun (2) is 4 - 7 m3 / h; III. Large flow rate spraying stage Stop the small spray hole branch pipe (25), start the large spray hole branch pipe (24) to spray the wheel, stop spraying until the transition part between the rim and the spoke of the wheel becomes dark. Among them, the water pressure of the large spray hole branch pipe (24) connected to the large spray holes (22) in the upper part of the water outlet panel (21) is P1, and the water pressure of the large spray hole branch pipe (24) connected to the large spray holes (22) in the lower part of the water outlet panel (21) is P2; in this step, the water outlet speed of the large spray holes (22) is 7 - 12 m / s, and the water output of a single spray gun (2) is 20 - 22 m3 / h; Among them, P1 > P2 > P0; P0 is 0.05 - 0.15 MPa, P1 is 0.35 - 0.45 MPa, and P2 is 0.3 - 0.4 MPa.

2. The railway wheel cooling method according to claim 1, characterized in that: A plurality of convex bodies (26) extending from top to bottom are provided on the water outlet panel (21), and the large spray holes (22) and the small spray holes (23) are both arranged on one side surface of the convex bodies (26).

3. A method for cooling a railway wheel according to claim 2, characterized in that: The included angle between the side surface of the convex body (26) where the large spray holes (22) and the small spray holes (23) are located and the water outlet panel (21) is 40 - 50°.

4. A method for cooling a railway wheel according to claim 1, characterized in that: It also includes two large - diameter ring pipes and one small - diameter ring pipe. One large - diameter ring pipe is respectively connected to each large spray hole branch pipe (24) connected to the large spray holes (22) in the upper part of the water outlet panel (21), the other large - diameter ring pipe is respectively connected to each large spray hole branch pipe (24) connected to the large spray holes (22) in the lower part of the water outlet panel (21), and the small - diameter ring pipe is respectively connected to each small spray hole branch pipe (25).

5. A railway wheel cooling method according to any one of claims 1-4, characterized in that: The diameter of the large spray holes (22) is 4 - 5 mm, and the diameter of the small spray holes (23) is 1.5 - 2 mm.

6. A method for cooling a railway wheel according to claim 5, characterized in that: The carbon content of the steel of the wheel is 0.50 - 0.75%, and the wheel diameter is 840 - 1250 mm.

7. A preparation method of an iron wheel, comprising blank cutting, heating, forming, heat treatment and finishing, wherein, The heat treatment includes heating, cooling and tempering, and is characterized in that: the cooling step adopts a railway wheel cooling method as described in claim 6.

Images