Heat treatment cooling spray gun, application and railway wheel heat treatment method

Abstract

The invention discloses a heat treatment cooling spray gun which comprises a water inlet device, an adjusting device connected with the water inlet device and a water outlet nozzle connected with the adjusting device, and a plurality of water outlet cavities capable of independently spraying cooling water towards different areas of a wheel tread are formed in the water outlet nozzle. The adjusting device is arranged to be used for adjusting the flow of cooling water entering all the water outlet cavities. According to the heat treatment cooling spray gun, water flow and opening and closing control of all the water outlet cavities of the water outlet nozzle can be achieved, differential adjustment of cooling water flow in the axial direction and the radial direction of a wheel can be achieved, asymmetric distribution of cooling strength along with space (the axial direction and the radial direction of a rim) and time (the cooling strength is firstly weak and then strong) is achieved, and the cooling uniformity of the rim of the wheel can be improved. The invention further discloses application of the heat treatment cooling spray gun and a wheel heat treatment method.

Description

Technical Field

[0001] The invention belongs to the technical field of heat treatment of railway wheels, and in particular relates to a heat treatment cooling spray gun, a use thereof and a heat treatment method for railway wheels. Background Art

[0002] For the organization and performance of railway wheels, countries and regions around the world generally require that the microstructure in the rim wear area is fine pearlite + a small amount of ferrite, and at the same time have good comprehensive properties such as strength and toughness. In terms of wheel heat treatment technology, although it is different in different countries, from the perspective of publicly reported literature, the "overall heating + tread continuous spray quenching + overall tempering" mode is the mainstream. Among them, the tread continuous spray quenching is to use a constant large amount of water to directly spray the wheel tread surface, which is a key process that determines the organization and performance of the wheel rim. However, under this cooling method, the tread surface is in direct contact with the cooling medium, and the instantaneous temperature drop is extremely large. The heat inside the rim can only be carried away by the cooling medium by heat conduction to the near-surface layer of the tread, and the cooling rate is significantly lower than that of the tread surface. This huge difference in cooling rate between the tread surface and the inside of the rim not only causes the formation of abnormal non-pearlite organization near the surface of the tread, but also leads to insufficient cooling capacity inside the rim, resulting in uneven cooling of the entire cross-section of the rim along the radial direction, and the performance of the rim is greatly affected.

[0003] Controlling or eliminating the non-pearlite structure of the wheel, improving the uniformity of performance, and obtaining balanced and consistent cooling have long been technical problems that the industry needs to solve, and are also one of the research hotspots. In response to this, the existing iron wheel cooling process has also taken corresponding measures.

[0004] The Chinese patent application number 200810020421.5 discloses a heat treatment method for the surface of a high-carbon steel railway wheel rim, wherein during the cooling process, the wheel tread of the railway wheel is firstly sprayed with water for a short time with a small flow rate, and then the wheel tread is forced to be sprayed with water for a long time with a large flow rate. The invention also discloses a heat treatment device for implementing the above method, wherein the water inlet ring pipe is divided into a large flow rate water inlet ring pipe and a small flow rate water inlet ring pipe, the large flow rate water inlet ring pipe is connected to a plurality of large flow rate nozzles; and the small flow rate water inlet ring pipe is connected to a plurality of small flow rate nozzles.

[0005] The Chinese patent with the application number 201910358140.9 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 whole wheel to complete austenitization; then transporting it to the quenching table, keeping the wheel in a rotating state, and using a pressure step-increasing aerosol two-phase flow to spray the tread of the wheel; then putting the whole wheel into a tempering furnace for heat preservation, and finally taking it out for air cooling; the pressure step-increasing aerosol two-phase flow spraying the tread of the wheel includes three stages in sequence, controlling the wheel rotation speeds in the three stages as v1>v2>v3, the water pressures as P1<P2<P3, and the quenching cooling times as T1<T2<T3; the number of nozzles started in the three stages distributed at equal intervals along the circumferential direction of the wheel is M, 2M, and 3M in sequence.

[0006] Aiming at the situation that the cooling rate difference between the near-surface layer of the wheel tread and the inside of the wheel rim during the heat treatment cooling process of the wheel is too large, resulting in abnormal structures appearing in the near-surface layer of the tread and uneven radial cooling of the wheel rim, both of the above two schemes adopt the method of first spraying and cooling the wheel tread with a small flow rate and then using a large flow rate for spraying and cooling, so that the cooling rate area from the wheel tread to the inside of the wheel rim is uniform, and the probability of abnormal structures appearing in the near-surface layer of the tread is reduced. However, both of these two schemes only consider the uniformity of the cooling speed of the wheel rim along the radial direction, without considering the cooling uniformity of the wheel rim in the axial and circumferential directions. In the actual heat treatment process, under the action of gravity, the cooling medium is concentrated at the wheel rim at the lower end of the wheel, resulting in the cooling rate at the lower end wheel rim being significantly greater than the cooling rate at the upper end wheel rim, thus affecting the cooling uniformity of the wheel rim in the axial direction and reducing the performance of the wheel rim.

[0007] In addition, the existing railway wheel cooling treatment devices in the prior art have not taken corresponding measures for the cooling uniformity of the wheel rim in the axial direction. The Chinese patent with the application number 201810189670.0 discloses a special combined nozzle for wheel quenching and its adjustment method, including 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 spraying panel arranged 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 spraying panel is provided with water outlet holes for the first set of nozzles. The second set of nozzles is installed on the nozzle water spraying 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 in this scheme is integrated on the water spraying 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 wheel rim cross-section, and it cannot solve the problem of the cooling uniformity of the wheel rim in the axial direction mentioned above.

[0008] It is desirable to provide an improved heat treatment cooling lance and a method for heat treatment of railway wheels, particularly with regard to how to manufacture high quality railway wheels. Summary of the invention

[0009] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a heat treatment cooling spray gun, the purpose of which is to improve the cooling uniformity of the wheel rim.

[0010] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a heat treatment cooling spray gun, including a water inlet device, an adjusting device connected to the water inlet device and a water outlet nozzle connected to the adjusting device, a plurality of water outlet cavities which can independently spray cooling water toward different areas of the wheel tread are arranged in the water outlet nozzle, and the adjusting device is arranged to adjust the cooling water flow rate entering each water outlet cavity.

[0011] Nine water outlet cavities are arranged in the water outlet nozzle, and the nine water outlet cavities are arranged in a nine-square grid.

[0012] A water outlet panel is arranged on the water outlet nozzle, and water outlet areas are arranged on the water outlet panel at positions corresponding to each of the water outlet cavities. The water outlet areas are provided with water outlet eyes for allowing cooling water to pass through. The number of water outlet eyes in each water outlet area is arranged to be the same and / or different, and the aperture of the water outlet eyes in each water outlet area is arranged to be the same and / or different.

[0013] The water outlet panel and the water outlet nozzle are detachably connected, and a sealing ring is arranged between the water outlet panel and the water outlet nozzle.

[0014] There are nine water outlet areas in total, namely the first water outlet area, the second water outlet area, the third water outlet area, the fourth water outlet area, the fifth water outlet area, the sixth water outlet area, the seventh water outlet area, the eighth water outlet area and the ninth water outlet area. The first water outlet area, the second water outlet area, the third water outlet area, the fourth water outlet area, the fifth water outlet area, the sixth water outlet area, the seventh water outlet area, the eighth water outlet area and the ninth water outlet area respectively correspond to the nine water outlet cavities in the water outlet nozzle, and the aperture sizes of the water outlet eyes in the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area are the same. The aperture sizes of the water outlet eyes of the fifth water outlet area and the eighth water outlet area are the same, the first water outlet area, the fourth water outlet area and the seventh water outlet area are in the first row, and the first water outlet area, the fourth water outlet area and the seventh water outlet area are arranged sequentially from top to bottom, the second water outlet area, the fifth water outlet area and the eighth water outlet area are in the second row, and the second water outlet area, the fifth water outlet area and the eighth water outlet area are arranged sequentially from top to bottom, the third water outlet area, the sixth water outlet area and the ninth water outlet area are in the third row, and the third water outlet area, the sixth water outlet area and the ninth water outlet area are arranged sequentially from top to bottom, and the aperture size of the water outlet eye of the first water outlet area is larger than the aperture size of the water outlet eye of the second water outlet area.

[0015] The number of water outlet eyes in the seventh water outlet area, the eighth water outlet area and the ninth water outlet area is less than the number of water outlet eyes in the remaining water outlet areas.

[0016] The regulating device includes a water outlet branch pipe and an on-off control valve arranged on the water outlet branch pipe. The two ends of the water outlet branch pipe are respectively connected to the water inlet device and the water outlet nozzle. The number of the water outlet branch pipes is the same as the number of the water outlet cavities.

[0017] The water outlet nozzle and the water inlet device are arranged on a base, and the water outlet nozzle and the base are made of aluminum alloy.

[0018] The present invention also provides a use of a heat treatment cooling spray gun, which is used to spray cooling water on the wheel tread, and achieves spatial and temporal differentiated distribution of cooling intensity by differentially adjusting the flow rates of axial and radial cooling water in the wheel.

[0019] The present invention also provides a wheel heat treatment method, which uses the heat treatment cooling spray gun and includes the steps of:

[0020] S1, heating the wheel as a whole;

[0021] S2, spray-quenching the wheel tread using the heat treatment cooling spray gun;

[0022] S3. Temper the wheel as a whole.

[0023] In the step S1, the blank wheel is placed in a heating furnace for heating, the uniform heating temperature is 840-920°C, the uniform temperature holding time is 1.25-2 hours, and the total heating time is 2.5-4 hours.

[0024] In the step S2, the wheel after heating is transferred to a quenching station, and the quenching station is evenly distributed along the circumference with three heat treatment cooling spray guns.

[0025] In step S2, when water is discharged from the water outlets of the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area of ​​the heat treatment cooling spray gun, the flow rate of the heat treatment cooling spray gun is 30 to 35 tons per hour; when water is discharged from the water outlets of the second water outlet area, the fifth water outlet area and the eighth water outlet area of ​​the heat treatment cooling spray gun, the flow rate of the heat treatment cooling spray gun is 3 to 5 tons per hour.

[0026] When it is necessary to regulate the axial structure and performance uniformity of the wheel, in the step S2, at least one of the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area is controlled to discharge water, and at the same time, at least one of the second water outlet area, the fifth water outlet area and the eighth water outlet area is controlled to discharge water, and the spray quenching cooling time is 200 to 450 seconds.

[0027] When it is necessary to regulate the radial structure and performance uniformity of the wheel, in the step S2, firstly, the water outlet of at least one of the second water outlet area, the fifth water outlet area and the eighth water outlet area is controlled to discharge water, and the spray quenching cooling time is 60 to 180 seconds, and then the water outlet of the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area is controlled to discharge water.

[0028] In the step S3, the wheel after the spray quenching is transferred to a tempering furnace for heating, the soaking temperature is 470-510° C., and the total tempering time is 4-6 hours.

[0029] The heat treatment cooling spray gun of the present invention can realize the water flow and opening and closing control of each water outlet cavity of the water outlet nozzle, can realize the differentiated adjustment of the cooling water flow in the axial and radial directions of the wheel, and realize the asymmetric distribution of cooling intensity with space (axial and radial directions of the rim) and time ("weak first and strong later"), which can improve the cooling uniformity of the wheel rim. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] This specification includes the following drawings, which show the following contents:

[0031] Figure 1 It is a structural schematic diagram of the heat treatment cooling spray gun of the present invention;

[0032] Figure 2 is a top view of the heat treatment cooling spray gun of the present invention;

[0033] Figure 3 It is the front view of the water outlet panel;

[0034] Figure 4 Schematic diagram of the cross-section grid hardness test of the wheel rim of Example 3 and Comparative Example 3;

[0035] Figure 5 Schematic diagram of the circumferential cross-section grid hardness test of the wheel rim of Example 3 and Comparative Example 3;

[0036] Figure 6 This is the grid hardness distribution of the transverse section of the wheel rim of Example 3 (2 blocks separated by 90°);

[0037] Figure 7 This is the grid hardness distribution of the transverse section of the wheel rim of Example 3 (2 blocks separated by 90°);

[0038] Figure 8 This is the grid hardness distribution of the circumferential section of the wheel rim of Example 3 (two blocks separated by 90°);

[0039] Fig. 9 This is the mesh hardness distribution of the circumferential section of the wheel rim of Example 3 (2 blocks separated by 90°);

[0040] Fig.10 Schematic diagram of sampling positions of wheel rim fracture toughness test specimens for Example 4 and Comparative Example 4 (six specimens are uniformly distributed at intervals of 60° along the circumference);

[0041] Fig.11 The shapes and dimensions of the finished specimens of the wheel rim fracture toughness of Example 4 and Comparative Example 4 (compact tensile CT30 test specimens);

[0042] Fig.12 It is the ellipsoidal or granular ferrite (i.e., intragranular ferrite) in the microstructure of the fracture toughness test specimen of the wheel in Example 4;

[0043] Fig.13 This is the microstructure of the wheel tread near the surface (2.5 mm from the surface) of Example 5;

[0044] Fig.14 This is the microstructure of the subsurface layer (13 mm from the surface) of the wheel tread of Example 5;

[0045] Fig.15 This is the microstructure of the inner part (40 mm from the surface) of the wheel rim of Example 5;

[0046] Fig.16This is the microstructure of the wheel tread near the surface (2.5 mm from the surface) of Example 5;

[0047] Fig.17 This is the microstructure of the subsurface layer (13 mm from the surface) of the wheel tread of Comparative Example 5;

[0048] Fig.18 This is the microstructure of the inner part of the wheel rim (40 mm from the surface) of Comparative Example 5;

[0049] Markings in the figure are: 1. water inlet pipe; 2. water inlet chamber; 3. opening and closing control valve; 4. water outlet branch pipe; 5. water outlet nozzle; 6. water outlet panel; 7. base; 8. first water outlet area; 9. second water outlet area; 10. third water outlet area; 11. fourth water outlet area; 12. fifth water outlet area; 13. sixth water outlet area; 14. seventh water outlet area; 15. eighth water outlet area; 16. ninth water outlet area. DETAILED DESCRIPTION

[0050] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention and facilitating their implementation.

[0051] Since improving the cooling uniformity of the railway wheel rim can improve the uniformity of the rim's hardness, fracture toughness and other properties, it is beneficial to improve the performance of the wheel, especially to prevent or slow down the occurrence of wheel out-of-round, eccentric wear, crack initiation and other use problems, and to improve the uniformity of wear during the entire life cycle. Therefore, in order to solve the deficiencies of the prior art, inhibit or eliminate the non-pearlite structure near the surface of the wheel tread caused by traditional constant large-flow quenching cooling, ensure the consistency of the structure, improve the uniformity of the performance, and manufacture high-quality railway wheels, it is particularly necessary to provide a heat treatment cooling spray gun and a railway wheel heat treatment method.

[0052] First, as Figures 1 to 3 As shown, the present invention provides a heat treatment cooling spray gun, including a base 7, a water inlet device, an adjusting device connected to the water inlet device and a water outlet nozzle 5 connected to the adjusting device, wherein a plurality of water outlet cavities which can independently spray cooling water toward different areas of the wheel tread are arranged in the water outlet nozzle 5, and the adjusting device is arranged to adjust the cooling water flow rate entering each water outlet cavity.

[0053] Specifically, if Figure 1As shown, the water outlet nozzle 5 and the water inlet device are fixedly arranged on the base 7, the adjusting device is located between the water outlet nozzle 5 and the water inlet device, the water inlet device is composed of a water inlet pipe 1 and a water inlet chamber 2, one end of the water inlet pipe 1 is fixedly connected to the water inlet of the water inlet chamber 2, one end of the adjusting device is fixedly connected to the water outlet of the water inlet chamber 2, and the other end of the adjusting device is fixedly connected to the water inlet of the water outlet nozzle 5.

[0054] like Figure 1 As shown, the water inlet chamber 2 is a square shell structure with a hollow interior, the water inlet pipe 1 is circular, three water inlet chambers 2 are provided, and the three water inlet chambers 2 are arranged in sequence from top to bottom, and each water inlet chamber 2 is connected to a water inlet pipe 1 respectively.

[0055] Preferably, the water inlet pipe 1 and the water inlet chamber 2 are both made of cast iron.

[0056] Preferably, the water outlet nozzle 5 and the base 7 are made of aluminum alloy for light weight and corrosion resistance.

[0057] like Figures 1 to 3 As shown, the water outlet cavity is a hollow cavity provided inside the water outlet nozzle 5 for storing cooling water. Nine water outlet cavities are provided inside the water outlet nozzle 5, and the nine water outlet cavities are arranged in a nine-square grid, that is, the nine water outlet cavities are distributed in a 3×3 matrix. The nine-square grid arrangement ensures the uniform distribution of the water outlet cavities. In the 3×3 matrix, each water outlet cavity occupies a fixed position, so that the water flow can be evenly distributed inside the water outlet nozzle 5.

[0058] like Figure 1 and Figure 2 As shown, the regulating device includes a water outlet branch pipe 4 and an on-off control valve 3 arranged on the water outlet branch pipe 4. The on-off control valve 3 is used to control the on-off of the water outlet branch pipe 4. The two ends of the water outlet branch pipe 4 are respectively connected to the water inlet device and the water outlet nozzle 5. The number of the water outlet branch pipes 4 is the same as the number of the water outlet cavities.

[0059] like Figure 1 and Figure 2 As shown, nine water outlet branch pipes 4 are provided, each of which is provided with an on-off control valve 3, one end of the water outlet branch pipe 4 is connected to the water inlet chamber 2, and the other end of the water outlet branch pipe 4 is connected to the water outlet nozzle 5, and each water outlet branch pipe 4 is used to guide the cooling water from the water inlet chamber 2 to a water outlet chamber. Each water inlet chamber 2 is connected to three water outlet branch pipes 4 respectively.

[0060] Preferably, the water outlet branch pipe 4 is made of polyethylene.

[0061] like Figures 1 to 3As shown, a water outlet panel 6 is provided on the water outlet nozzle 5, and water outlet areas are provided on the water outlet panel 6 at positions corresponding to each water outlet cavity, and water outlet holes are provided in the water outlet area for cooling water to pass through, and the number of water outlet holes in each water outlet area is set to be the same or different, and the apertures of the water outlet holes in each water outlet area are set to be the same or different. The maximum diameter of the water outlet hole is set to 4.0-6.0 mm, and the minimum diameter of the water outlet hole is set to 1.0-3.0 mm. The number of water outlet holes provided at the lower end of the water outlet panel 6 is less than that at the middle and upper ends. The purpose of this design is to control the water flow in different areas of the panel to achieve control of the cooling intensity of different parts of the wheel tread.

[0062] Preferably, the water outlet panel 6 is detachably connected to the water outlet nozzle 5. A sealing ring is provided between the water outlet panel 6 and the water outlet nozzle 5, and the sealing ring is used to seal between the water outlet panel 6 and the water outlet nozzle 5 to prevent leakage of cooling water, and the sealing ring is a rubber ring.

[0063] like Figures 1 to 3 As shown, there are nine water outlet areas on the water outlet panel 6, and the nine water outlet areas are arranged in a nine-square grid, that is, the nine water outlet areas are distributed in a 3×3 matrix. The nine water outlet areas are respectively the first water outlet area 8, the second water outlet area 9, the third water outlet area 10, the fourth water outlet area 11, the fifth water outlet area 12, the sixth water outlet area 13, the seventh water outlet area 14, the eighth water outlet area 15 and the ninth water outlet area 16, and the nine water outlet cavities are respectively the first water outlet cavity, the second water outlet cavity, the third water outlet cavity, the fourth water outlet cavity, the fifth water outlet cavity, the sixth water outlet cavity, the seventh water outlet cavity, the eighth water outlet cavity and the ninth water outlet cavity. The first water outlet area 8 corresponds to the first water outlet cavity, the second water outlet area 9 corresponds to the second water outlet cavity, the third water outlet area 10 corresponds to the third water outlet cavity, the fourth water outlet area 11 corresponds to the fourth water outlet cavity, the fifth water outlet area 12 corresponds to the fifth water outlet cavity, the sixth water outlet area 13 corresponds to the sixth water outlet cavity, the seventh water outlet area 14 corresponds to the seventh water outlet cavity, the eighth water outlet area 15 corresponds to the eighth water outlet cavity, and the ninth water outlet area 16 corresponds to the ninth water outlet cavity.

[0064] The first water outlet area 8, the second water outlet area 9, the third water outlet area 10, the fourth water outlet area 11, the fifth water outlet area 12, the sixth water outlet area 13, the seventh water outlet area 14, the eighth water outlet area 15 and the ninth water outlet area 16 respectively correspond to the nine water outlet cavities in the water outlet nozzle 5, and the aperture sizes of the water outlet eyes of the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 are the same, the aperture sizes of the water outlet eyes of the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 are the same, and the first water outlet area 8, the fourth water outlet area 11 and the seventh water outlet area 14 are in the first row, and the first water outlet area 8, the fourth water outlet area 11 and the seventh water outlet area 14 are arranged sequentially from top to bottom, the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 are in the second row, and the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 are arranged sequentially from top to bottom, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 are in the third row, and the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 are arranged sequentially from top to bottom, and the aperture of the water outlet eye of the first water outlet area 8 is larger than the aperture of the water outlet eye of the second water outlet area 9.

[0065] The first water outlet area 8, the second water outlet area 9 and the third water outlet area 10 are in the first row and the second water outlet area 9 is located between the first water outlet area 8 and the third water outlet area 10, the third water outlet area 10, the fourth water outlet area 11 and the fifth water outlet area 12 are in the second row and the fourth water outlet area 11 is located between the third water outlet area 10 and the fifth water outlet area 12, the seventh water outlet area 14, the eighth water outlet area 15 and the ninth water outlet area 16 are in the third row and the eighth water outlet area 15 is located between the seventh water outlet area 14 and the ninth water outlet area 16 are in the third row. The three water outlet areas in the second column are located between the three water outlet areas in the first column and the three water outlet areas in the third column. The three water outlet areas in the second row are located between the three water outlet areas in the first row and the three water outlet areas in the third row.

[0066] Preferably, the number of water outlets in the seventh water outlet area 14, the eighth water outlet area 15 and the ninth water outlet area 16 is less than the number of water outlets in the remaining water outlet areas. The number of water outlets in the first water outlet area 8 is greater than the number of water outlets in the second water outlet area 9. The number of water outlets in the first water outlet area 8, the third water outlet area 10, the fourth water outlet area 11 and the sixth water outlet area 13 is the same. The number of water outlets in the second water outlet area 9 is the same as the number of water outlets in the fifth water outlet area 12, and the number of water outlets in the seventh water outlet area 14 is the same as the number of water outlets in the ninth water outlet area 16.

[0067] In the second aspect, the present invention provides a use of a heat treatment cooling spray gun, which is used to spray cooling water on the wheel tread, and achieves spatial and temporal differentiated distribution of cooling intensity by differentially adjusting the axial and radial cooling water flow rates of the wheel, thereby achieving regulation of organizational and performance uniformity.

[0068] Furthermore, differentially adjusting the cooling water flow in the wheel axial direction refers to selectively opening or closing the control valve of the water outlet branch pipe 4, by increasing or decreasing the water outlet holes with larger apertures on both sides of the water outlet panel 6 (i.e. corresponding to Figure 3 The first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16) and the water outlet eye with a smaller aperture in the middle (i.e. corresponding to Figure 3 The cooling intensity of the wheel axial direction is adjusted by adjusting the number of the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15.

[0069] Furthermore, differentially regulating the cooling water flow in the radial direction of the wheel refers to selectively opening or closing the control valve of the water outlet branch pipe 4, by increasing or decreasing the number of water outlet holes with smaller apertures in the middle of the water outlet panel 6 (i.e. corresponding to Figure 3 At the same time, the water outlet with a smaller aperture in the middle is opened first for short-term weak cooling, and then the water outlets with larger apertures on both sides are selectively opened for strong cooling, so as to adjust the cooling intensity in the radial direction of the wheel and realize the differentiated distribution of the wheel cooling intensity over time.

[0070] In a third aspect, the present invention provides a railway wheel heat treatment method, which refers to first heating the wheel as a whole before quenching, then directly quenching the wheel tread surface with circulating water, and using the above-mentioned cooling intensity to achieve differentiated distribution in space and time according to the wheel organization and performance requirements, and then tempering the wheel as a whole after the wheel quenching is completed.

[0071] The present invention provides a wheel heat treatment method, which adopts the heat treatment cooling spray gun of the above structure and comprises the following steps:

[0072] S1, heating the wheel as a whole;

[0073] S2, spray-quenching the wheel tread using a heat treatment cooling spray gun;

[0074] S3. Temper the wheel as a whole.

[0075] In the above step S1, overall heating means that the blank wheel is placed in a heating furnace for heating, the uniform heating temperature is 840-920°C, the uniform temperature holding time is 1.25-2h, and the total heating time is 2.5-4h.

[0076] The specific setting of the uniform heating temperature and the total heating time is determined according to the chemical composition, size specifications, loading quantity, material distribution method, actual condition of the heating furnace, etc. of the wheels during batch production. The uniform heating section is maintained for 1.25 to 2 hours to achieve sufficient austenitization.

[0077] In the above step S2, the spray quenching cooling means that the wheel after heating is transferred to a quenching station, and the quenching station is evenly distributed along the circumference with three heat treatment cooling spray guns.

[0078] In the above step S2, when the water outlets of the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 of the heat treatment cooling spray gun discharge water, cooling water enters the water outlet cavities corresponding to the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 respectively, and the opening and closing control valves 3 of the water outlet branch pipes 4 connecting the six water outlet cavities are all opened, and the heat treatment The flow rate of the heat treatment cooling spray gun is 30 to 35 tons per hour, and the water output of the six water outlet branch pipes 4 is consistent; when water is discharged from the water outlet eyes of the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 of the heat treatment cooling spray gun, cooling water enters the water outlet cavities corresponding to the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 respectively, and the opening and closing control valves 3 of the water outlet branch pipes 4 connecting the three water outlet cavities are all opened, the flow rate of the heat treatment cooling spray gun is 3 to 5 tons per hour, and the water output of the three water outlet branch pipes 4 is consistent.

[0079] When it is necessary to regulate the axial organization and performance uniformity of the wheel, a stronger cooling is started. At this time, in the above step S2, at least one of the water outlet areas among the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 is controlled to discharge water, and at least one of all the water outlet cavities corresponding to the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 is controlled to enter cooling water, and at the same time, at least one of the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 is controlled to discharge water, and the second water outlet area 9, At least one of all the water outlet cavities corresponding to the fifth water outlet area 12 and the eighth water outlet area 15 enters cooling water, that is, the on-off control valve 3 on at least one of the six water outlet branch pipes 4 connecting the first water outlet cavity, the fourth water outlet cavity, the seventh water outlet cavity, the third water outlet cavity, the sixth water outlet cavity and the ninth water outlet cavity and the on-off control valve 3 on at least one of the three water outlet branch pipes 4 connecting the second water outlet cavity, the fifth water outlet cavity and the eighth water outlet cavity are selectively opened, and the quenching cooling time is set to 200-450s, and the specific time is determined according to the chemical composition of the wheel steel, the rim thickness, etc., to achieve differentiated adjustment of the axial cooling of the wheel to improve the uniformity of the cross-sectional hardness of the wheel.

[0080] When it is necessary to regulate the uniformity of the radial structure and performance of the wheel, weaker cooling is started first, and then strong cooling is performed. At this time, in the above step S2, first control the water outlet of at least one of the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 (that is, at least one of the three water outlet branches 4 connecting the second water outlet cavity, the fifth water outlet cavity and the eighth water outlet cavity is opened. The opening and closing control valves 3 of the three water outlet branches 4 connecting the second water outlet cavity, the fifth water outlet cavity and the eighth water outlet cavity can also be opened), the spray quenching cooling time is 60 to 180 seconds, and then selectively control the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 15, the water outlet of the water outlet area 16, the water outlet of the water outlet area 17, the water outlet of the water outlet area 18, the water outlet of the water outlet area 19, the water outlet of the water outlet area 20, the water outlet of the water outlet area 21, the water outlet of the water outlet area 22, the water outlet of the water outlet area 23, the water outlet of the water outlet area 24, the water outlet of the water outlet area 25, the water outlet of the water outlet area 26, the water outlet of the water outlet area 27, the water outlet of the water outlet area 28, the water outlet of the water outlet area 29, the water outlet of the water outlet area 30, the water outlet of the water outlet area 31, the water outlet of the water outlet area 32 Water is discharged from the water outlet holes of the water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 (that is, the on-off control valve 3 on at least one of the six water outlet branch pipes 4 connecting the first water outlet cavity, the fourth water outlet cavity, the seventh water outlet cavity, the third water outlet cavity, the sixth water outlet cavity and the ninth water outlet cavity is selectively opened, or the on-off control valves 3 of the six water outlet branch pipes 4 connecting the first water outlet cavity, the fourth water outlet cavity, the seventh water outlet cavity, the third water outlet cavity, the sixth water outlet cavity and the ninth water outlet cavity can all be opened) to strongly cool the wheel, thereby realizing differentiated adjustment of radial cooling of the wheel to improve the structural consistency and cross-sectional hardness uniformity of the wheel rim cross section.

[0081] In the above step S3, overall tempering means that the wheel after quenching cooling is transferred to a tempering heating furnace for heating, the uniform heating temperature is 470-510°C, the total tempering time is 4-6h, and after tempering, the wheel is taken out of the furnace and air-cooled to room temperature.

[0082] For the organization and performance of railway wheels, countries and regions around the world generally require that the microstructure in the rim wear area is fine pearlite + a small amount of ferrite, and has good comprehensive properties such as strength and toughness. In terms of wheel heat treatment technology, although it is different in different countries, from the perspective of publicly reported literature, the "overall heating + tread continuous quenching + overall tempering" mode is the mainstream. Among them, the tread continuous quenching is to use a constant large amount of water to directly spray the wheel tread surface, which is the key process that determines the organization and performance of the wheel rim. The constant water flow rate leads to a very high cooling rate near the surface of the wheel tread, which far exceeds the critical cooling rate of the complete pearlite transformation of the wheel steel material. Due to the large thickness of the rim section, the cooling rate inside the rim decreases significantly with the increase of depth. The large cooling rate gradient directly leads to uneven cooling at different depths along the radial direction of the rim, thereby generating an undesirable martensite and bainite mixed structure near the surface of the wheel tread that is unfavorable to the service performance of the wheel (such as "early peeling"), and also leads to a large hardness gradient in the rim. In addition, because the wheel rim has a special-shaped surface structure (thick inside and thin outside), and the water flow is bound to accumulate at the lower end of the wheel due to gravity, resulting in a cooling difference of "weak on top and strong on bottom", making the cooling of the wheel axial direction uneven.

[0083] The core idea of ​​the present invention is to design a cooling spray gun equipped with a "nine-grid" water outlet panel 6 based on the structural characteristics of the wheel rim profile, which can realize the independent control of the water outlet strength of nine areas, and adopt the "weak first and then strong" cooling method according to actual needs, so as to realize the differential adjustment of the cooling intensity of the wheel rim with space and time, and achieve the asymmetric quenching cooling effect of "shape + process" combination dual control, thereby significantly improving the organizational consistency and performance uniformity of the wheel rim.

[0084] The above heat treatment cooling spray gun and railway wheel heat treatment method have the following advantages:

[0085] 1) The spray gun consists of a water inlet device, an adjustment device, a water outlet nozzle 5 and a base 7. The three water inlet pipes 1 can independently control the water pressure and the total amount of water inlet;

[0086] 2) The water outlet nozzle 5 adopts a "nine-square grid" type fine partition design, and is divided into nine cavities inside, which are respectively connected to nine water outlet branches 4. The front end is a detachable water outlet panel 6, which can independently control the water outlet, thereby realizing the adjustment of the cooling intensity of different areas of the wheel tread;

[0087] 3) The water outlet panel 6 is also finely divided into nine areas, corresponding to the nine cavities in the nozzle, and the diameter and number of the water outlet holes on the panel are set differently, with the large hole diameter being φ4.0-6.0mm and the small hole diameter being φ1.0-3.0mm. The number of water outlet holes at the lower end is less than that at the middle and upper ends. The water flow in different areas of the panel is controlled to achieve control of the cooling intensity of different parts of the wheel tread;

[0088] 4) By selectively opening or closing the control valve of the water outlet branch pipe 4, the cooling water flow in the axial and radial directions of the wheel is differentially adjusted to achieve differential distribution of cooling intensity with space (axial and radial directions of the rim) and time ("weak first and strong later"), thereby achieving an asymmetric quenching cooling effect, thereby achieving uniformity of organization and performance, and effectively solving the problem of uneven cooling of the wheel rim;

[0089] 5) The use of the spray gun and asymmetric quenching and cooling process can significantly reduce or completely eliminate the non-pearlite structure on the tread surface after the wheel heat treatment and cooling, so that the rim area obtains a uniform fine pearlite + a small amount of ferrite structure, ensuring the consistency of the structure and helping to improve the metal utilization rate;

[0090] 6) The use of the spray gun and asymmetric quenching cooling process can significantly improve the uniformity of the cross-sectional hardness of the wheel rim, so that the maximum range of the cross-sectional hardness in the axial and circumferential directions is controlled within 5HB;

[0091] 7) The use of the spray gun and asymmetric quenching cooling process can significantly improve the fracture toughness level and uniformity of the vanadium-containing wheel rim, increase the mean fracture toughness by more than 20%, reduce the range by more than 70%, and achieve a good strength-toughness match.

[0092] Embodiment 1:

[0093] like Figure 1-2 As shown, the wheel heat treatment cooling spray gun described in this embodiment is composed of four parts: a water inlet device, an adjusting device, a water outlet nozzle 5 and a base 7. The water inlet device is composed of three circular water inlet pipes 1 and three rows of square water inlet chambers 2. The water inlet pipes 1 and the water inlet chambers 2 are both made of cast iron. The adjusting device is composed of nine water outlet branches 4, each of which is equipped with an opening and closing control valve 3. The water outlet branch pipes 4 are made of polyethylene. The water outlet nozzle 5 is a "nine-square grid" type, and the interior is finely divided into nine water outlet chambers, which are respectively connected to the nine water outlet branches 4, and the front end is a water outlet panel 6. The water outlet panel 6 and the nozzle chamber are rubber sealed, and the water outlet panel 6 is also finely divided into nine areas, corresponding to the nine water outlet chambers in the water outlet nozzle 5.

[0094] like Figure 3As shown, the water outlet panel 6 is detachable and easy to install. It is sealed with the nozzle cavity by rubber. The water outlet panel 6 is finely divided into nine areas, and the diameter and number of the water outlet holes on the water outlet panel 6 are set differently, corresponding to the nine water outlet cavities in the water outlet nozzle 5. Among them, the water outlet holes in the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 have the same diameter of φ4.0-6.0 mm, and are symmetrically distributed on the left and right as a whole; the second water outlet area in the middle The diameter of the water outlet holes in the water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 is φ1.0~3.0mm; and the number of water outlet holes in the seventh water outlet area 14, the eighth water outlet area 15 and the ninth water outlet area 16 arranged at the lower end is less than that in the fourth water outlet area 11, the fifth water outlet area 12, the sixth water outlet area 13 arranged at the middle end and the first water outlet area 8, the second water outlet area 9 and the third water outlet area 10 arranged at the upper end. Controlling the water outlet at the lower end can avoid the problem of uneven cooling caused by the water outlet at the middle and upper ends gathering at the lower end due to gravity. Differentiated control of the water flow in different areas of the water outlet panel 6 can achieve the adjustment of the cooling intensity of different parts of the wheel tread, and obtain a more balanced and consistent cooling effect.

[0095] When the water outlet holes with larger apertures on both sides of the water outlet panel 6 (i.e. corresponding to Figure 3 When the on-off control valves 3 of the first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13 and the ninth water outlet area 16 are all opened, the flow rate of each spray gun is 30 to 35 tons per hour, and the water output of the six water outlet branches 4 is consistent; when the water outlet eye with a smaller aperture in the middle on the control water outlet panel 6 (i.e., corresponding to Figure 3 When the on-off control valves 3 of the second water outlet area 9, the fifth water outlet area 12 and the eighth water outlet area 15 are all opened, the flow rate of each spray gun is 3 to 5 tons per hour, and the water output of the three water outlet branches 4 is consistent.

[0096] In addition, for the sake of lightness and corrosion resistance, the water outlet nozzle 5 and the base 7 are made of aluminum alloy.

[0097] Embodiment 2:

[0098] This embodiment describes the use of the spray gun in Embodiment 1. The spray gun is used to spray quench the wheel tread that has completed quenching heating, and the flow rates of axial and radial cooling water of the wheel are differentially adjusted to achieve spatial and temporal differential distribution of cooling intensity, thereby achieving regulation of uniformity of organization and performance.

[0099] Differentiated adjustment of the cooling water flow in the wheel axial direction refers to selectively opening or closing the on-off control valve 3 of the water outlet branch pipe 4, by increasing or decreasing the water outlet holes with larger apertures on both sides of the water outlet panel 6 (i.e. corresponding to Figure 3The first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13, the ninth water outlet area 16) and the water outlet eye with a smaller aperture in the middle (i.e. corresponding to Figure 3 The cooling intensity of the wheel axial direction is adjusted by adjusting the number of the second water outlet area 9, the fifth water outlet area 12, and the eighth water outlet area 15.

[0100] Differentiated adjustment of the cooling water flow in the radial direction of the wheel refers to selectively opening or closing the on-off control valve 3 of the water outlet branch pipe 4, by increasing or decreasing the number of water outlet holes with smaller diameters in the middle of the water outlet panel 6 (i.e. corresponding to the number of outlet holes in the water outlet panel 6). Figure 3 At the same time, the water outlet with a smaller aperture in the middle is opened first for short-term weak cooling, and then the water outlets with larger apertures on both sides are selectively opened for strong cooling, so as to adjust the cooling intensity in the radial direction of the wheel and realize the differentiated distribution of the wheel cooling intensity over time.

[0101] Embodiment 3:

[0102] The main chemical components of the wheel of Example 3 are shown in Table 1, and the rim thickness B is 68 mm. The blank wheel is placed in a heating furnace for heating as a whole, and the temperature is gradually raised to 870±10°C (the target absorptive temperature is 870°C, and the temperature uniformity of the ±10°C industrial furnace) after 1.25 hours, and then kept warm for 1.25 hours to fully austenitize, and then taken out of the furnace and transferred to the quenching table for spray quenching cooling. The quenching table is evenly distributed along the circumference with three cooling spray guns described in Example 1. During the quenching stage, the inner side of the wheel faces upward (the wheel axis is a vertical line at this time), and the opening and closing control valve 3 of the water outlet branch pipe 4 corresponding to the water outlet cavity of the first water outlet area 8, the second water outlet area 9, the third water outlet area 10, the fourth water outlet area 11, the sixth water outlet area 13, and the eighth water outlet area 15 is opened at the same time, and then the opening and closing control valve 3 of the water outlet branch pipe 4 corresponding to one of the water outlet areas of the seventh water outlet area 14 and the ninth water outlet area 16 is opened. By selectively opening or closing the opening and closing control valve 3 of the corresponding water outlet branch pipe 4, the number of water outlet holes on the water outlet panel 6 is increased or decreased, and the cooling intensity of the wheel axial direction is adjusted by differentially adjusting the cooling water flow rate of the wheel axial direction. The duration of the quenching stage is 250s. After the quenching is completed, the wheel is transferred to the tempering furnace for tempering treatment via the chain plate bed, and the absorptive temperature is 480±10℃ (the target absorptive temperature is 480℃, ±10℃ industrial furnace temperature uniformity), the total tempering time is 6h, and the furnace is air-cooled to room temperature after the tempering is completed.

[0103] Comparative Example 3:

[0104] The main chemical components of the wheel of comparative example 3 are shown in Table 1, and the rim thickness B is 69 mm, and the chemical components and rim thickness are equivalent to those of the wheel of embodiment 3. In terms of heat treatment system, the quenching heating and tempering process are the same as those of embodiment 3, except that the existing constant large water flow rate is used for cooling in the spray quenching stage, and 6 rigid spray guns are evenly distributed along the circumference of the quenching table. The spray guns are equipped with an "integrated" water outlet panel 6, without specific subdivision areas, and the water outlet hole diameter is consistent, with a diameter of φ4.0-5.0 mm. The flow rate of each spray gun is 18-20 tons per hour, and the duration of the entire spray quenching stage is 270 seconds.

[0105] like Figure 4-5 As shown in the figure, according to GB / T 231.1 "Metallic Materials Brinell Hardness Test Part 1: Test Method", two transverse section hardness specimens (90° apart) and two circumferential section hardness specimens (90° apart) are directly taken from the wheel rim after heat treatment for grid hardness test. The hardness extreme difference (i.e. the difference between the maximum and minimum hardness) at the same depth under the tread is defined as the hardness uniformity. Figure 6-7 As shown, the maximum range of the axial section hardness of the wheel rim of Example 3 at 5, 15, 25, 35, and 45 mm from the tread is 3, 2, 3, 4, and 3 HB respectively, while the maximum range of the axial section hardness of the wheel rim of Comparative Example 3 at 5, 15, 25, 35, and 45 mm from the tread is 13, 12, 12, 8, and 9 HB respectively. Figure 8-9 As shown, the maximum range of the circumferential section hardness of the wheel rim of Example 3 at 5, 15, 25, and 35 mm from the tread is 2, 3, 4, and 3 HB respectively, while the maximum range of the circumferential section hardness of the wheel rim of Comparative Example 3 at 5, 15, 25, and 35 mm from the tread is 15, 11, 12, and 14 HB respectively. It can be seen that compared with Comparative Example 3, whether in the axial direction or in the circumferential direction, the hardness fluctuation at the same depth of the wheel rim of Example 3 at the tread is smaller, and the section hardness uniformity is better.

[0106] Table 1 Main chemical components of wheels of the embodiment and comparative example (wt%)

[0107] element C Si Mn P S Cr Ni Mo V Example 3 0.54 0.32 0.75 0.009 0.005 0.17 0.13 0.02 0.13 Comparative Example 3 0.55 0.30 0.74 0.009 0.007 0.17 0.14 0.02 0.13 Example 4 0.65 0.52 0.82 0.010 0.009 0.25 0.15 0.04 0.10 Comparative Example 4 0.65 0.54 0.83 0.011 0.009 0.24 0.16 0.05 0.11 Example 5 0.77 0.89 0.85 0.010 0.010 0.13 0.20 0.05 0.06 Comparative Example 5 0.75 0.92 0.87 0.010 0.008 0.14 0.24 0.05 0.05

[0108] Embodiment 4:

[0109] The main chemical components of the wheel of Example 4 are shown in Table 1, and the rim thickness B is 89 mm. When performing heat treatment, firstly, the blank wheel is placed in a heating furnace as a whole for heating, and the temperature is gradually raised to 850±10°C (the target uniform heating temperature is 850°C, and the temperature uniformity of the industrial furnace is ±10°C) after 1.5 hours, and then the wheel is kept warm for 1.5 hours to fully austenitize and then taken out of the furnace. Then the wheel is transferred to a quenching table for spray quenching cooling. The quenching table is evenly distributed along the circumference with three cooling spray guns described in Example 1. During the spray quenching stage, the inner side of the wheel faces upward, and the water outlet with a smaller aperture in the middle (i.e., the corresponding Figure 3 The water outlets of the second water outlet area 9, the fifth water outlet area 12, and the eighth water outlet area 15 in the middle spray cooling water to perform short-term weak cooling on the wheel. The cooling time is 120s, and then the water outlets with larger apertures on both sides (i.e. corresponding to Figure 3 The first water outlet area 8, the fourth water outlet area 11, the seventh water outlet area 14, the third water outlet area 10, the sixth water outlet area 13, and the ninth water outlet area 16) spray cooling water to strongly cool the wheel, and the cooling time is 240s. By controlling the water outlet of the smaller aperture in the middle of the water outlet panel 6 and the larger aperture on both sides of the water outlet panel 6, the cooling water flow in the radial direction of the wheel is differentially adjusted, thereby adjusting the cooling intensity in the radial direction of the wheel, and realizing the differentiated distribution of the cooling intensity of the wheel over time. After the spray quenching is completed, the wheel is transferred to the tempering furnace via the chain plate bed for tempering treatment. The average heat temperature is 490±10℃ (the target average heat temperature is 490℃, ±10℃ industrial furnace temperature uniformity), and the total tempering time is 5h. After the tempering is completed, the wheel is taken out of the furnace and air-cooled to room temperature.

[0110] Comparative Example 4:

[0111] The main chemical components of the wheel of comparative example 4 are shown in Table 1, the rim thickness B is 90 mm, and the chemical components and rim thickness are equivalent to those of the wheel of embodiment 4. In terms of heat treatment system, the quenching heating and tempering process are the same as those of embodiment 4, except that the existing constant large water flow rate is used for cooling in the spray quenching stage, and 6 rigid spray guns are evenly distributed along the circumference of the quenching table. The spray guns are equipped with an "integrated" water outlet panel 6, without specific subdivision areas, and the water outlet hole diameter is consistent, with a diameter of φ4.0-5.0 mm. The flow rate of each spray gun is 18-20 tons per hour, and the duration of the entire spray quenching stage is 360 seconds.

[0112] like Fig.10 As shown in the figure, 6 fracture toughness test specimens are uniformly distributed along the circumference at the corresponding parts of the rim (one specimen is taken at every 60° interval). The shape and size of the final finished specimen are shown in Fig.11, and the compact tensile fracture toughness test was carried out in accordance with GB / T4161-2007 "Metallic Material Plane Strain Fracture Toughness KIC Test Method". The 6 fracture toughness Kq values ​​of the wheel rim of Example 4 were 69.4, 68.2, 72.6, 71.5, 72.0, and 69.8 MPa·m1 / 2, with an average of 70.6 MPa·m1 / 2 and a range of 4.4 MPa·m1 / 2, while the 6 fracture toughness Kq values ​​of the wheel rim of Comparative Example 4 were 50.4, 59.4, 49.8, 62.3, 55.5, and 67.1 MPa·m1 / 2, with an average of 57.4 MPa·m1 / 2 and a range of 17.3 MPa·m1 / 2. It can be seen that compared with Comparative Example 4, the fracture toughness average of the wheel rim of Example 4 increased by 23.0%, the range decreased by 74.6%, and the fracture toughness level and uniformity were good. Through the dissection of the tested fracture toughness specimens, it was found that Fig.12 As shown, ferrite in the form of ellipsoid or granules (i.e., intracrystalline ferrite) is precipitated in the microstructure of the wheel of Example 4, and its size is mainly concentrated in 4-6 μm, while this type of ferrite does not appear in the microstructure of the wheel of Comparative Example 4. This is because the differential adjustment of the cooling water flow in the radial direction of the wheel by "weak first and then strong" is adopted, which induces the intracrystalline nucleation of ferrite during the cooling phase transformation stage. This type of ferrite has a distinct interface with the pearlite matrix, and the interface is flat and smooth. Its formation increases the phase interface in the microstructure, and multiple more complex deflections occur during the crack propagation process, consuming more energy, which is manifested in the wheel having higher fracture toughness in the macroscopic way.

[0113] Embodiment 5:

[0114] The main chemical components of the wheel of Example 5 are shown in Table 1, and the rim thickness B is 102 mm. When performing heat treatment, firstly, the blank wheel is placed in a heating furnace as a whole for heating, and the temperature is gradually raised to 890±10°C after 2 hours (the target uniform heating temperature is 890°C, and the temperature uniformity of the industrial furnace is ±10°C), and then kept warm for 2 hours to fully austenitize and then taken out of the furnace. Then the wheel is transferred to a quenching table for spray quenching cooling. The quenching table is evenly distributed along the circumference with three cooling spray guns described in Example 1. During the spray quenching stage, the outer side of the wheel faces upward, and the water outlet with a smaller aperture in the middle (i.e., the corresponding Figure 3 The second water outlet area 9, the fifth water outlet area 12, and the eighth water outlet area 15 in the middle of the wheel are used to spray cooling water to perform weak cooling on the wheel for 180 seconds, and then the water outlets with larger apertures on both sides are controlled (i.e., opening the water outlets Figure 3The water outlets of the first water outlet area 8, the third water outlet area 10, the fourth water outlet area 11, the sixth water outlet area 13, and the water outlets of the seventh water outlet area 14 or the ninth water outlet area 16) spray cooling water to perform strong cooling on the wheel for 330 seconds. By controlling the water outlet of the water outlet with a smaller aperture in the middle and the water outlet with a larger aperture on both sides of the water outlet panel 6, the cooling water flow in the radial direction of the wheel is differentially adjusted, thereby adjusting the cooling intensity in the radial direction of the wheel, and realizing the differentiated distribution of the cooling intensity of the wheel over time. After the spray quenching is completed, the wheel is transferred to the tempering furnace via the chain plate bed for tempering treatment. The uniform heating temperature is 500±10℃ (the target uniform heating temperature is 500℃, ±10℃ temperature uniformity of the industrial furnace), and the total tempering time is 4h. After the tempering is completed, the wheel is taken out of the furnace and air-cooled to room temperature.

[0115] Comparative Example 5:

[0116] The main chemical components of the wheel of comparative example 5 are shown in Table 1, the rim thickness B is 100 mm, and the chemical components and rim thickness are equivalent to those of the wheel of embodiment 5. In terms of heat treatment system, the quenching heating and tempering process are the same as those of embodiment 5, except that the existing constant large water flow rate is used for cooling in the spray quenching stage, and 6 rigid spray guns are evenly distributed along the circumference of the quenching table. The spray guns are equipped with an "integrated" water outlet panel 6, without specific subdivision areas, and the water outlet hole diameter is consistent, with a diameter of φ4.0-5.0 mm. The flow rate of each spray gun is 18-20 tons per hour, and the duration of the entire spray quenching stage is 460 seconds.

[0117] like Fig.10 As shown in FIG. 1 , samples were taken at different depths 70 mm from the inner side of the rim for microstructure analysis. The microstructures of the wheel tread near the surface (2.5 mm from the surface), the subsurface (13 mm from the surface) and the inner side of the rim (40 mm from the surface) are shown in FIG. Figures 13-15 As shown in FIG. 1 , it can be seen that the microstructures of the wheel rim of Example 5 at different depths are all fine pearlite + a small amount of ferrite, and the microstructures are consistent and uniform. The microstructures of the wheel tread near the surface, subsurface and inside the rim of Comparative Example 5 are as follows: Figures 16 to 18As shown. In contrast, the wheel of Comparative Example 5 generates undesirable non-pearlite structures of martensite, bainite and their mixtures in the near-surface and sub-surface layers of the tread, with a thickness of about 15 mm. The presence of the non-pearlite layer destroys the continuity and uniformity of the wheel matrix structure. Under the action of the wheel-rail contact stress, the uncoordinated elastic-plastic deformation at the interface of the non-pearlite / matrix structure produces stress concentration, which induces and promotes the initiation and propagation of fatigue cracks, thereby reducing the contact fatigue and wear resistance of the wheel, leading to early failure, and is a potential source of driving failure and hazard. Therefore, most industry standards and technical conditions have clear restrictions on this. In production practice, the conventional approach to control or eliminate the non-pearlite layer is to increase the design margin of the wheel, and then mechanically remove it after heat treatment, which leads to problems such as low metal utilization and high production costs.

[0118] The above-mentioned reference embodiments 1 to 5 and the attached Figures 1 to 18 A heat treatment cooling spray gun, its uses and a railway wheel heat treatment method are described in detail, which is only illustrative and not restrictive. Several embodiments can be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. Heat treatment cooling spray gun, characterized in that, It includes a water inlet device, a regulating device connected to the water inlet device and a water outlet nozzle connected to the regulating device. A plurality of water outlet cavities are arranged in the water outlet nozzle, which can independently spray cooling water toward different areas of the wheel tread. The regulating device is configured to regulate the cooling water flow entering each water outlet cavity.

2. The heat treatment cooling spray gun according to claim 1, characterized in that: Nine water outlet cavities are arranged in the water outlet nozzle, and the nine water outlet cavities are arranged in a nine-square grid.

3. The heat treatment cooling spray gun according to claim 1, characterized in that: A water outlet panel is arranged on the water outlet nozzle, and water outlet areas are arranged on the water outlet panel at positions corresponding to each of the water outlet cavities. The water outlet areas are provided with water outlet eyes for allowing cooling water to pass through. The number of water outlet eyes in each water outlet area is arranged to be the same and / or different, and the aperture of the water outlet eyes in each water outlet area is arranged to be the same and / or different.

4. The heat treatment cooling spray gun according to claim 3, characterized in that: The water outlet panel and the water outlet nozzle are detachably connected, and a sealing ring is arranged between the water outlet panel and the water outlet nozzle.

5. The heat treatment cooling spray gun according to claim 3, characterized in that: There are nine water outlet areas in total, namely the first water outlet area, the second water outlet area, the third water outlet area, the fourth water outlet area, the fifth water outlet area, the sixth water outlet area, the seventh water outlet area, the eighth water outlet area and the ninth water outlet area. The first water outlet area, the second water outlet area, the third water outlet area, the fourth water outlet area, the fifth water outlet area, the sixth water outlet area, the seventh water outlet area, the eighth water outlet area and the ninth water outlet area respectively correspond to the nine water outlet cavities in the water outlet nozzle, and the aperture sizes of the water outlet eyes in the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area are the same. The aperture sizes of the water outlet eyes of the fifth water outlet area and the eighth water outlet area are the same, the first water outlet area, the fourth water outlet area and the seventh water outlet area are in the first row, and the first water outlet area, the fourth water outlet area and the seventh water outlet area are arranged sequentially from top to bottom, the second water outlet area, the fifth water outlet area and the eighth water outlet area are in the second row, and the second water outlet area, the fifth water outlet area and the eighth water outlet area are arranged sequentially from top to bottom, the third water outlet area, the sixth water outlet area and the ninth water outlet area are in the third row, and the third water outlet area, the sixth water outlet area and the ninth water outlet area are arranged sequentially from top to bottom, and the aperture size of the water outlet eye of the first water outlet area is larger than the aperture size of the water outlet eye of the second water outlet area.

6. The heat treatment cooling spray gun according to claim 5, characterized in that: The number of water outlet eyes in the seventh water outlet area, the eighth water outlet area and the ninth water outlet area is less than the number of water outlet eyes in the remaining water outlet areas.

7. The heat treatment cooling spray gun according to any one of claims 1 to 6, characterized in that: The regulating device includes a water outlet branch pipe and an on-off control valve arranged on the water outlet branch pipe. The two ends of the water outlet branch pipe are respectively connected to the water inlet device and the water outlet nozzle. The number of the water outlet branch pipes is the same as the number of the water outlet cavities.

8. The heat treatment cooling spray gun according to any one of claims 1 to 7, characterized in that: The water outlet nozzle and the water inlet device are arranged on a base, and the water outlet nozzle and the base are made of aluminum alloy.

9. Use of the heat treatment cooling spray gun as described in any one of claims 1 to 8, which is used to spray cooling water on the wheel tread, and achieve spatial and temporal differentiated distribution of cooling intensity by differentially adjusting the flow rate of axial and radial cooling water of the wheel.

10. A wheel heat treatment method, characterized in that: The heat treatment cooling spray gun according to any one of claims 1 to 8 is used, and comprises the steps of: S1, heating the wheel as a whole; S2, spray-quenching the wheel tread using the heat treatment cooling spray gun; S3. Temper the wheel as a whole.

11. The wheel heat treatment method according to claim 10, characterized in that: In the step S1, the blank wheel is placed in a heating furnace for heating, the uniform heating temperature is 840-920°C, the uniform temperature holding time is 1.25-2h, and the total heating time is 2.5-4h.

12. The wheel heat treatment method according to claim 10, characterized in that: In the step S2, the wheel after heating is transferred to a quenching station, and the quenching station is evenly distributed along the circumference with three heat treatment cooling spray guns.

13. The wheel heat treatment method according to claim 10, characterized in that: In step S2, when water is discharged from the water outlets of the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area of ​​the heat treatment cooling spray gun, the flow rate of the heat treatment cooling spray gun is 30 to 35 tons per hour; when water is discharged from the water outlets of the second water outlet area, the fifth water outlet area and the eighth water outlet area of ​​the heat treatment cooling spray gun, the flow rate of the heat treatment cooling spray gun is 3 to 5 tons per hour.

14. The wheel heat treatment method according to claim 10, characterized in that: When it is necessary to regulate the axial structure and performance uniformity of the wheel, in the step S2, at least one of the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area is controlled to discharge water, and at the same time, at least one of the second water outlet area, the fifth water outlet area and the eighth water outlet area is controlled to discharge water, and the spray quenching cooling time is 200 to 450 seconds.

15. The wheel heat treatment method according to claim 10, characterized in that: When it is necessary to regulate the radial structure and performance uniformity of the wheel, in the step S2, firstly, the water outlet of at least one of the second water outlet area, the fifth water outlet area and the eighth water outlet area is controlled to discharge water, and the spray quenching cooling time is 60 to 180 seconds, and then the water outlet of the first water outlet area, the fourth water outlet area, the seventh water outlet area, the third water outlet area, the sixth water outlet area and the ninth water outlet area is controlled to discharge water.

16. The wheel heat treatment method according to any one of claims 10 to 15, characterized in that: In the step S3, the wheel after spray quenching is transferred to a tempering furnace for heating, the soaking temperature is 470-510° C., and the total tempering time is 4-6 hours.

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