A blank wheel for improving the performance of a wheel rim and a production method thereof

Abstract

The present invention provides a blank wheel for improving the performance of a wheel rim and a production method thereof. By designing the tread profile of the blank wheel rim as a concave tread profile, quenching with the outer side facing upwards and adopting a combined quenching method of direct injection and oblique injection, the invention improves the structure, performance and their distribution state of the wheel rim, improves the performance distribution state of the wheel rim cross-section, enables the entire wheel rim cross-section to obtain uniform and relatively fine pearlite structure, especially the internal performance of the wheel rim, and creates favorable conditions for improving the service performance of the wheel. The method of the present invention can improve the performance and its distribution of the wheel rim cross-section, and the process is simple and easy to implement, facilitating industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of wheels for rail transit and preparation methods thereof, and more specifically, to a blank wheel for improving wheel rim performance and a production method thereof. By improving the tread profile of the blank wheel and the controlled cooling process during production, the cross-sectional microstructure performance of the wheel rim can be improved. Background Art

[0002] With the rapid development of my country's rail transit, the conditions of rail transit lines are complex and changeable (such as lines with many small curvature radii), the speed of vehicles is gradually increasing, the passenger capacity is getting bigger and bigger, and the abnormal wear of wheels is becoming more and more serious, which can easily cause vehicle vibration, etc., and may even cause early failure of train parts, which has a direct impact on the safety and reliability of train operation.

[0003] During the wheel water quenching process, the temperature of the rim tread is distributed in a step-like manner from the surface to the inside, and the organizational transformation gradually occurs from the surface to the inside. During the transformation process, the near tread, outer side, and inner side are affected by cooling water or water mist, and the cooling rate is faster, the pearlite structure generated is finer, and the hardness level is higher. However, the area inside the rim has a slower cooling rate, the pearlite structure generated is coarser, and the hardness level is lower, which forms a "V"-shaped distribution on the hardened surface with low hardness in the middle and high hardness on both sides. During the quenching process, sometimes the "torrent effect" is caused by the water jet and the rotation of the roller. The "torrent effect" will reduce the water flow at the nominal rolling circle of the tread and increase the water flow at the outer side, so that the cooling rate of the outer side is higher and the hardness is higher. The hardness of the cross-section of the wheel rim presents a " / "-shaped distribution. This has a great impact on the performance of the wheel, especially in the later service process, the nominal rolling circle where the wheel and rail contact most frequently has a low hardness, which is prone to serious wear, peeling, loss of roundness and other damages. Summary of the invention

[0004] The purpose of the present invention is to provide a blank wheel and a production method for improving the performance of the wheel rim, by optimizing the tread profile (profile) of the blank wheel rim, quenching the outer side of the wheel upward, and adopting a controlled cooling method combining direct injection and oblique injection to improve the wheel rim structure and its distribution, so as to improve the service performance of the wheel, especially the mid- and late-term service performance of the wheel.

[0005] The specific technical solutions of the present invention are as follows:

[0006] A method for producing a blank wheel for improving wheel rim performance comprises the following steps:

[0007] 1) Hot forming of blank wheels;

[0008] 2) After the wheel is heated, the quenching treatment is performed with the outer side of the wheel facing upward, and the nozzles are evenly distributed along the circumference of the wheel. For every two adjacent nozzles, one nozzle sprays water directly on the wheel tread, and the other nozzle sprays water obliquely on the wheel tread;

[0009] 3) Perform tempering treatment.

[0010] Step 1) Specifically includes the following technological processes: billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling;

[0011] In step 1), for billet ingot cutting, parameters such as the height of the billet are determined according to the wheel specifications and the casting weight;

[0012] In step 1), for the heating, the temperature is controlled at 1200 - 1280 °C;

[0013] In step 1), preforming and forming are carried out by rolling in a semi-closed mold.

[0014] In step 1), the rolling process is carried out on a horizontal rolling mill, which is the most important process for forming the wheel rim of the wheel. During rolling: control the tread profile of the blank wheel. The tread profile of the blank wheel in the present invention is optimized on the basis of the common LM ( Figure 1 Profile 1 in it) or the S1002CN tread profile to obtain Profile 2, which is a concave tread profile. The concave tread profile is an arc with a radius of R. For example, Figure 1 in it, the root of the wheel flange is connected to the tread through a transition arc. The lowest point of the concave tread profile is the reference point. The horizontal distance from one end of the arc with a radius of R connected to the transition arc to the reference point is L2, and the horizontal distance from the other end of the arc with a radius of R to the reference point is L1. The vertical distance from the highest point of the wheel flange top to the reference point is S; among them, R is 70 - 100 mm, S is 33 - 38 mm, L1 is 35 - 45 mm, and L2 is 35 - 45 mm; the values of L1 and L2 can be the same or different; preferably, the tread profile of the blank wheel is an arc with R = 70 - 100 mm, which is the optimal choice of the present invention. The tread profile of the blank wheel can be an arc with the shape of an elliptical arc surface, a trapezoidal arc surface, etc. During rolling, it should be ensured that the maximum single-sided allowance (relative to the finished wheel) of the wheel rim tread of the blank wheel is 10 - 13 mm, and the minimum should be 5 - 8 mm.

[0015] In step 2), a ring heating furnace is used for heating, the heating temperature is 840 - 900 °C, and the holding time is 2.5 - 3.5 h;

[0016] In step 2), the nozzle water column directly spraying on the wheel tread means that the nozzle water column is perpendicular to the wheel tread, and the other nozzle water column obliquely spraying on the wheel tread means that the nozzle water column forms an angle of 45 - 60° with the tangent of the wheel tread.

[0017] Preferably, in step 2), the quenching treatment is carried out on a quenching table. There are supporting rollers on the quenching table, and there is a nozzle on each side of the supporting roller. The water column of the nozzle on one side of the supporting roller is perpendicular to the tread of the wheel, and the water column of the nozzle on the other side of the supporting roller forms an angle of 45-60° with the tangent of the tread of the wheel. During the quenching process, the supporting roller supports the quenched wheel. The water column of the nozzle on one side of the supporting roller is perpendicular to the tread of the wheel, and the water column of the nozzle on the other side of the supporting roller forms an angle of 45-60° with the tangent of the tread of the wheel, which can prevent the wheel from displacement during the quenching process.

[0018] In step 2), the nozzles are evenly distributed along the circumferential direction of the wheel. Preferably, 6 box-type nozzles are evenly distributed along the circumferential direction of the wheel. Each nozzle is distributed with weak-cooling water outlet holes and strong-cooling water outlet holes. The water flow rate of each nozzle is equal, and the water pressure is 0.1±0.01 MPa. The water flow rate of the weak-cooling water outlet holes is 8-10 m 3 / h, and the water flow rate of the strong-cooling water outlet holes is 18-24 m 3 / h.

[0019] Further, in step 2), first weak-cooling is carried out, and then strong-cooling. The weak-cooling is: the weak-cooling water outlet holes spray water for weak-cooling, and the spraying and quenching time is 60-120 s. The strong-cooling is: the strong-cooling water outlet holes spray water for strong-cooling, and the spraying and quenching time is 240-400 s. The specific spraying and quenching time depends on the thickness of the wheel rim. If the thickness of the wheel rim is large, the spraying and quenching time is long; if the thickness of the wheel rim is small, the spraying and quenching time is short.

[0020] During the water quenching process, the temperature of the tread of the wheel rim from the surface to the inside shows a stepped distribution, and the tissue transformation occurs gradually from the surface to the inside. As Figure 3 shown, during the transformation process, the near-tread (region 1) is affected by the cooling water, and the cooling rate is the fastest. The pearlite structure formed is fine, and the hardness level is the highest. The outer side (region 2) and the inner side (region 4) are affected by air and water mist, and the cooling rate is also relatively fast. The pearlite structure formed is fine, and the hardness level is relatively high. However, in region 3 located inside the wheel rim, the effect of the cooling water is small, the cooling rate is slow, the pearlite structure formed is coarser, and the hardness level is lower. This forms a "V"-type distribution with low hardness in the middle and high hardness on both sides on the hardness cross-section. On the other hand, the box-type nozzles on the left side of the supporting roller adopt an inclined spraying method. During the water flow spraying process, the "swirling effect" is caused by the rotation of the supporting roller. Generally, the "swirling effect" will reduce the water flow rate at the nominal rolling circle of the tread and increase the water flow rate at the outer side, making the cooling rate of the outer side higher and the hardness higher, aggravating the "V"-type distribution, and even further evolving into a " / " -type distribution.

[0021] The present invention adopts a concave tread profile and a water spraying method combining direct spraying and inclined spraying alternately to solve the above problems for heat treatment:

[0022] 1) The region with higher hardness can be extended to the deeper region 3 position. Combining with the weak-cooling process to control the abnormal tissue near the tread, and combining with the strong-cooling process to further increase the hardness of the region 3 position.

[0023] 2) The arc surface changes the quenching critical conditions, increasing the contact area between the cooling water and the cooled object, absorbing more heat, increasing the cooling rate in Region 3, refining the pearlite structure, and improving the strength and hardness level. That is, by changing the quenching critical conditions through the profile change, the performance of the wheel rim is optimized.

[0024] 3) By adopting an alternating combination of direct injection and oblique injection water spraying method, combined with the concave tread profile, the water film on the tread can be broken by high-pressure direct current water, changing the contact state between the water flow and the workpiece, the contact area between the water flow and the workpiece, etc., improving the cooling effect, and alleviating or even eliminating the "V" or " / " type hardness distribution.

[0025] In step 3), after the quenched wheel is stationary in the air for 5 - 15 minutes of cooling, tempering treatment is carried out.

[0026] The said tempering treatment is: tempering treatment is carried out at 480 - 520 °C, and the tempering time ≥ 4 h; after the tempering is completed, it is air-cooled after being taken out of the furnace and then machined to the finished product size.

[0027] A blank wheel for improving the performance of a wheel rim provided by the present invention is produced by using the above production method.

[0028] Aiming at the problem that the hardness of the axial section of the wheel rim shows a "V" or " / " type distribution after heat treatment of the existing wheel, the present invention provides a controlled cooling method that optimizes the tread profile of the wheel rim of the blank wheel, quenches with the outer side facing up and adopts a combination of direct injection and oblique injection to improve the structure, performance and its distribution state of the wheel rim, improves the performance distribution state of the wheel rim section, enables the entire wheel rim section to obtain a uniform and relatively fine pearlite structure, especially the internal performance of the wheel rim, creating favorable conditions for improving the service performance of the wheel. The method of the present invention can improve the performance and its distribution of the wheel rim section, and the process is simple and easy to implement, facilitating industrial production. Brief Description of the Drawings

[0029] Figure 1 is the tread profile of the blank wheel, Profile 2 is the tread profile of the blank wheel designed by the present invention, and Profile 1 is the profile of the comparative example;

[0030] Figure 2 is the schematic diagram of wheel quenching. The water column of the nozzle on the left side of the roller is perpendicular to the tread of the wheel rim, and the water column of the nozzle on the right side of the roller forms an angle of 45 - 60° with the tread tangent;

[0031] Figure 3 is the schematic diagram of the quenching environment and cooling area distribution of the wheel rim;

[0032] Figure 4 is the temperature-time change diagram at 5 mm below the tread and 35 mm below the tread in Example 1 and Comparative Example 1;

[0033] Figure 5 Hardness distribution diagrams of the wheel rims of Example 1 and Comparative Example 1, (a) is Example 1, and (b) is Comparative Example 1;

[0034] Figure 6 Hardness distribution laws at 5 mm and 35 mm below the tread of the wheel rims of Example 1 and Comparative Example 1;

[0035] Figure 7 Pearlite lamellar spacing at 5 mm and 35 mm below the tread of the wheel rims of Example 1 and Comparative Example 1;

[0036] Figure 8 Hardness distribution diagrams of the wheel rims of Example 2 and Comparative Example 2, (a) is Example 2, and (b) is Comparative Example 2;

[0037] Figure 9 Hardness distribution laws at 5 mm and 35 mm below the tread of the wheel rims of Example 2 and Comparative Example 2;

[0038] Figure 10 Hardness distribution diagrams of the wheel rims of Example 3 and Comparative Example 3, (a) is Example 3, and (b) is Comparative Example 3;

[0039] Figure 11 Hardness distribution laws at 5 mm and 35 mm below the tread of the wheel rims of Example 3 and Comparative Example 3;

[0040] Figure 12 Hardness distribution diagrams of the wheel rims of Example 4 and Comparative Example 4, (a) is Example 4, (b) is Comparative Example 4, and (c) is Comparative Example 5;

[0041] Figure 13 Hardness distribution laws at 5 mm and 35 mm below the tread of the wheel rims of Example 4 and Comparative Example 4;

[0042] Figure 14 Hardness distribution laws at 5 mm and 35 mm below the tread of the wheel rims of Example 4 and Comparative Example 5. Detailed implementation manners

[0043] A production method of a blank wheel for improving the performance of a wheel rim provided by the present invention includes the following steps:

[0044] 1): The hot forming of the blank wheel is completed according to the production process of billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling; the billet ingot cutting determines the billet height, etc. according to the wheel specifications and input weight, the billet heating temperature is controlled at 1200 - 1280 °C, and the preforming and forming are carried out by rolling in a semi-closed mold. The rolling process is carried out on a horizontal rolling mill, which is the most important process for the formation of the wheel rim; during rolling: control the tread profile of the blank wheel, and the tread profile of the blank wheel of the present invention is optimized on the basis of the common LM ( Figure 1 tread profile 1) or S1002CN tread profile in the middle to obtain profile 2, which is a concave tread profile, and the concave tread profile is an arc with a radius of R. As Figure 1 shown in the figure, at the root of the wheel flange, it is connected to the tread through a transition arc. The lowest point of the concave tread profile is the base point. The horizontal distance from one end of the arc with a radius of R connected to the transition arc to the base point is L2, and the horizontal distance from the other end of the arc with a radius of R to the base point is L1. The vertical distance from the highest point of the wheel flange top to the base point is S; among them, R is 70 - 100 mm, S is 33 - 38 mm, L1 is 35 - 45 mm, and L2 is 35 - 45 mm; the values of L1 and L2 can be the same or different; preferably, the tread profile of the blank wheel is an arc with R = 70 - 100 mm, which is the optimal choice of the present invention. The tread profile of the blank wheel can be an elliptical arc surface, a trapezoidal arc surface, etc. During rolling, it should be ensured that the maximum single-sided allowance (relative to the finished wheel) of the wheel rim tread of the blank wheel is 10 - 13 mm, and the minimum should be 5 - 8 mm.

[0045] 2): Put the wheel obtained in step 1) into a ring heating furnace at 840 - 900 °C and keep it warm for 2.5 - 3.5 h, then take it out of the furnace and carry out quenching treatment in the way of the outer side facing up. Quenching is carried out by spraying water with 6 box nozzles evenly distributed along the circumference of the wheel. As Figure 2 shown, the quenching treatment is carried out on a quenching table. There are supporting rollers on the quenching table, and there is one nozzle on each side of the supporting rollers. The water column of the nozzle on the left side of the supporting roller is perpendicular to the tread of the wheel rim, and the water column of the nozzle on the right side of the supporting roller forms an angle of 45 - 60° with the tread tangent; each nozzle is distributed with weak cooling water outlet holes and strong cooling water outlet holes, and the water flow rate of each nozzle is equal, the water pressure is 0.1 ± 0.01 MPa, the water output of the weak cooling water outlet holes is 8 - 10 m 3 / h, and the water output of the strong cooling water outlet holes is 18 - 24 m 3 / h; the weak cooling spray quenching time is 60 - 120 s, and the strong cooling spray quenching time is 240 - 400 s. The specific spray quenching time depends on the rim thickness of the wheel rim. The larger the rim thickness of the wheel rim, the longer the spray quenching time; the smaller the rim thickness of the wheel rim, the shorter the spray quenching time;

[0046] 3) After the wheels processed in step 2) are left stationary in the air for cooling for 5 - 15 min, they are put into a tempering furnace with a furnace temperature of 480 - 520 °C for tempering treatment. The tempering time is ≥ 4 h. After air cooling out of the furnace, they are machined to the finished product size.

[0047] The following describes the present invention in detail with reference to the following examples and comparative examples.

[0048] Example 1

[0049] A production method of a blank wheel for improving the performance of a wheel rim, specifically:

[0050] In this example, hot forming is carried out using the wheel steel 1 in Table 1. The diameter of the steel billet is φ380 mm. The hot forming of the blank wheel is completed according to the production process of steel billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 870 mm (the outer diameter of the finished wheel is 840 mm). During the rolling process, the tread of the blank wheel is rolled into the Figure 1 profile 2 therein, where R is 80 mm, S is 6 mm, L1 is 35 mm, and L2 is 35 mm. Then the wheel is put into an 850 °C ring heating furnace for heat preservation for 2.5 h and then discharged from the furnace. After discharging, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upward. There are 6 box-type nozzles evenly distributed along the circumferential direction of the wheel, as Figure 2 shown. There are carrier rollers on the quenching table. There is one nozzle on each side of the carrier roller. The water column of the nozzle on the left side of the carrier roller is perpendicular to the tread of the wheel rim, and the water column of the nozzle on the right side of the carrier roller forms a 45° angle with the tread tangent. Each nozzle is distributed with weak-cooling water outlet holes and strong-cooling water outlet holes. The water flow rate of each nozzle is equal, and the water pressure is 0.1 ± 0.01 MPa. The water output of the weak-cooling water outlet holes is 8 m 3 / h, the spraying quenching time is 60 s, the water output of the strong-cooling water outlet holes is 20 m 3 / h, and the strong-cooling spraying quenching time is 240 s. After quenching, the wheel is left stationary in the air for cooling for 5 min. Then the wheel is put into a tempering furnace with a furnace temperature of 500 °C for tempering treatment. The tempering time is ≥ 4 h. After air cooling out of the furnace, it is machined to the finished product size.

[0051] The present invention uses a concave arc tread profile to extend the region with higher hardness to a deeper region, and cooperates with the alternating combination of direct spraying and oblique spraying water spraying methods. On the one hand, the water film on the tread is broken by the direct current high-pressure water, and the contact state between the water flow and the workpiece, the contact area between the water flow and the workpiece, etc. are improved to enhance the cooling effect. On the other hand, the box-type nozzle on the left side of the carrier roller adopts the direct spraying method, which can also reduce the "torrent effect" caused by the water flow spraying and the carrier roller rotation, and improve the internal cooling rate of the wheel rim. Drill holes at 5 mm below the tread and 35 mm below the tread of the wheel rim relative to the corresponding finished wheel tread, with a hole depth of 70 mm, implant thermocouples, and conduct temperature measurement, as Figure 4As shown, it is obvious that the internal cooling rate of the entire rim in this embodiment is relatively high. According to Figure 4 it can be obtained that the greater the slope, the greater the cooling rate.

[0052] Comparative Example 1

[0053] A production method of a blank wheel, specifically:

[0054] The wheel steel used in this comparative example has the same furnace number and specification as that in Example 1. The hot forming of the blank wheel is completed according to the production process of billet ingot cutting → heating → descaling after furnace tapping → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 870 mm (the outer diameter of the finished wheel is 840 mm). During the rolling process, the tread of the blank wheel is rolled into Figure 1 Profile 1 in, that is, the LM tread profile. Then the wheel is put into an 880°C ring heating furnace for heat preservation for 2.5 h and then taken out of the furnace. After taking out of the furnace, quenching treatment is carried out. When quenching, the outer side of the wheel rim is facing downwards. Six box-type nozzles are evenly distributed along the circumferential direction of the wheel. The water column of the nozzle forms a 45° angle with the tread tangent line, and the strong cooling method is used for quenching cooling. The water output of the strong cooling water outlet is 20 m 3 / h, and the strong cooling spraying and quenching time is 300 s. After quenching, the wheel is put into a tempering furnace with a furnace temperature of 500°C for tempering treatment. The tempering time is ≥4 h, and it is air-cooled after taking out of the furnace and processed to the finished product size.

[0055] According to the requirements of BS EN 13262 "Railway applications - Wheelsets and bogies - Wheels - Product requirements", hardness and microstructure analysis are carried out on Example 1 and Comparative Example 1. Hardness measurement is carried out according to GB / T231.1 "Metallic materials - Brinell hardness test - Part 1: Test method", and metallographic microstructure detection is carried out according to GB / T 13298 "Test methods for metallic microstructures". The hardness and pearlite lamellar spacing of the wheel rims of Example 1 and Comparative Example 1 are as Figure 5 , Figure 6 , Figure 7 shown, Figure 5 in, (a) is Example 1, (b) is Comparative Example 1. From Figure 6 it can be seen that in Example 1, whether it is 5 mm below the tread or 35 mm below the tread, with the increase of the distance from the inner rim surface, the hardness change is not significant; for Comparative Example 1, 35 mm below the tread, with the increase of the distance from the inner rim surface, the hardness change is significant, the hardness of the wheel rim core is significantly reduced, and the hardness of the axial section of the wheel rim shows a "V"-shaped distribution. From Figure 7 it can be seen that for 5 mm below the tread and 35 mm below the tread of the wheel, the pearlite lamellar spacing of Example 1 is significantly smaller than that of Comparative Example 1. It can be seen that adopting the scheme of the present invention can significantly improve the tissue hardness distribution of the wheel rim part, especially improve the performance of the wheel rim core.

[0056] Table 1 Main chemical components of the wheel steels of each example and comparative example

[0057]

[0058] Note: The remaining amounts not shown in Table 1 are Fe and inevitable impurities.

[0059] Example 2

[0060] A production method of a blank wheel for improving the performance of a wheel rim, specifically:

[0061] In this example, the wheel steel 2 in Table 1 is used for hot forming. The diameter of the steel billet is φ450mm. The hot forming of the blank wheel is completed according to the production process of steel billet cutting and ingot → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 950mm (the outer diameter of the finished wheel is 920mm). During the rolling process, the tread of the blank wheel is rolled into Figure 1 Profile 2 therein, where R is 90mm, S is 8mm, L1 is 40mm, and L2 is 40mm. Then the wheel is put into an 880°C ring heating furnace for heat preservation for 2.5h and then taken out of the furnace. After taking out of the furnace, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upward. Six box nozzles evenly distributed along the circumferential direction of the wheel are as Figure 2 shown. The water column of the nozzle on the left side of the idler is perpendicular to the tread of the wheel rim, and the water column of the nozzle on the right side of the idler forms a 45° angle with the tread tangent. Each nozzle is distributed with weak-cooling water outlet holes and strong-cooling water outlet holes. The water outlet flow of each nozzle is equal, the water pressure is 0.1 ± 0.01MPa, the water outlet volume of the weak-cooling water outlet holes is 8m 3 / h, the quenching spraying time is 80s, the water outlet volume of the strong-cooling water outlet holes is 22m 3 / h, and the strong-cooling quenching spraying time is 320s. After quenching, the wheel is statically cooled in the air for 10min, and then the wheel is put into a tempering furnace with a furnace temperature of 500°C for tempering treatment. The tempering time is ≥4h, and after taking out of the furnace and air cooling, it is processed to the finished size.

[0062] Comparative Example 2

[0063] A production method of a blank wheel, specifically:

[0064] The wheel steel used in this comparative example has the same furnace number and specification as that in Example 2. The hot forming of the blank wheel is completed according to the production process of steel billet cutting and ingot → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 950mm (the outer diameter of the finished wheel is 920mm). During the rolling process, the tread of the blank wheel is rolled into Figure 1 Profile 1 therein. Then the wheel is put into an 880°C ring heating furnace for heat preservation for 2.5h and then taken out of the furnace. After taking out of the furnace, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces downward. Six box nozzles evenly distributed along the circumferential direction of the wheel, the water column of the nozzles forms a 45° angle with the tread tangent, and the strong-cooling method is used for quenching and cooling. The water outlet volume of the strong-cooling water outlet holes is 20m3 / h, the strong cooling spray quenching time is 400 s. After quenching, the wheel is put into a tempering furnace with a furnace temperature of 500 °C for tempering treatment, the tempering time is ≥4 h, and it is air-cooled after being taken out of the furnace and then machined to the finished size.

[0065] According to the requirements of BS EN 13262 "Railway applications - Wheelsets and bogies - Wheels - Product requirements", the hardness and microstructure analysis of Example 2 and Comparative Example 2 are carried out. The hardness measurement is carried out in accordance with GB / T 231.1 "Metallic materials - Brinell hardness test - Part 1: Test method", and the metallographic microstructure detection is carried out in accordance with GB / T 13298 "Test methods for metallic materials - Microstructure". The microstructure and the law of pearlite lamellar spacing of Example 2 and Comparative Example 2 are basically the same as those of Example 1 and Comparative Example 1. The hardness of the wheel rims of Example 2 and Comparative Example 2 is as Figure 8 , Figure 9 shown. It can be seen from Figure 9 that for Example 2, whether it is 5 mm below the tread or 35 mm below the tread, as the distance from the inner rim surface increases, the hardness changes little; for Comparative Example 2, whether it is 5 mm below the tread or 35 mm below the tread, as the distance from the inner rim surface increases, the hardness increases significantly and changes greatly, and the hardness of the axial section of the wheel rim shows a " / " - shaped distribution. It can be seen that adopting the solution of the present invention can significantly improve the distribution of the microstructure hardness of the wheel rim part, especially improving the performance of the core part of the wheel rim.

[0066] Example 3

[0067] A production method of a blank wheel for improving the performance of a wheel rim, specifically:

[0068] In this example, the wheel steel 3 in Table 1 is used for hot forming. The diameter of the steel billet is φ450 mm. The hot forming of the blank wheel is completed according to the production process of steel billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 1280 mm (the outer diameter of the finished wheel is 1250 mm). During the rolling process, the tread of the blank wheel is rolled into the Figure 1 profile 2 in, where R is 100 mm, S is 8 mm, L1 is 45 mm, and L2 is 45 mm. Then the wheel is put into a 900 °C ring heating furnace for heat preservation for 3.0 h and then taken out of the furnace. After taking out of the furnace, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upward, and 6 box-type nozzles evenly distributed along the circumferential direction of the wheel, as Figure 2 shown. The water column of the nozzle on the left side of the idler is perpendicular to the tread of the wheel rim, and the water column of the nozzle on the right side of the idler forms a 45° angle with the tread tangent. Each nozzle is distributed with weak cooling water outlet holes and strong cooling water outlet holes. The water flow rate of each nozzle is equal, the water pressure is 0.1 ± 0.01 MPa, the water discharge of the weak cooling water outlet holes is 8 m 3 / h, the spray quenching time is 100 s, and the water discharge of the strong cooling water outlet holes is 22 m 3 / h, and the strong cooling spray quenching time is 400 s. After quenching, the wheel is left stationary in the air for 15 min to cool, and then the wheel is put into a tempering furnace with a furnace temperature of 520 °C for tempering treatment. The tempering time is ≥5 h, and after air cooling out of the furnace, it is machined to the finished product size.

[0069] Comparative Example 3

[0070] A production method of a blank wheel, specifically:

[0071] The wheel steel used in this comparative example has the same furnace number and specification as that in Example 3. The hot forming of the blank wheel is completed according to the production process of steel billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 1280 mm (the outer diameter of the finished wheel is 1250 mm). During the rolling process, the tread of the blank wheel is rolled into Figure 1 Profile 1. Then the wheel is put into a 900 °C ring heating furnace for heat preservation for 3.0 h and then discharged from the furnace. After discharging, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upward, and 6 box-type nozzles are evenly distributed along the circumferential direction of the wheel. The water column of the nozzle forms a 60° angle with the tangent of the tread, and the strong cooling method is used for quenching cooling. The water output of the strong cooling water outlet is 22 m 3 / h, and the strong cooling spray quenching time is 480 s. After quenching, the wheel is put into a tempering furnace with a furnace temperature of 520 °C for tempering treatment. The tempering time is ≥5 h, and after air cooling out of the furnace, it is machined to the finished product size.

[0072] According to the requirements of BS EN 13262 "Railway applications - Wheelsets and bogies - Wheels - Product requirements", hardness and microstructure analysis are carried out on Example 3 and Comparative Example 3. Hardness measurement is carried out in accordance with GB / T 231.1 "Metallic materials - Brinell hardness test - Part 1: Test method", and metallographic microstructure detection is carried out in accordance with GB / T 13298 "Test methods for metallic microstructures". The microstructure and the law of pearlite lamellar spacing of Example 3 and Comparative Example 3 are basically the same as those of Example 1 and Comparative Example 1. The hardness of the wheel rims of Example 4 and Comparative Example 4 is as Figure 10 、 Figure 11 shown. It can be seen from Figure 11 that for Example 3, whether it is 5 mm below the tread or 35 mm below the tread, with the increase of the distance from the inner rim surface, the hardness change is not significant; for Comparative Example 3, whether it is 5 mm below the tread or 35 mm below the tread, with the increase of the distance from the inner rim surface, the hardness changes significantly; especially at 35 mm below the tread, the hardness of the axial section of the wheel rim shows a "V"-shaped distribution. It can be seen that adopting the scheme of the present invention can significantly improve the hardness distribution of the microstructure of the wheel rim part, especially improve the performance of the core part of the wheel rim.

[0073] Example 4

[0074] A production method of a blank wheel for improving the performance of the wheel rim, specifically:

[0075] In this embodiment, the hot forming is carried out using the wheel steel 4 in Table 1. The diameter of the steel billet is φ380mm. The hot forming of the blank wheel is completed according to the production process of steel billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 1000mm (the outer diameter of the finished wheel is 970mm). During the rolling process, the tread of the blank wheel is rolled into Figure 1 the profile 2 in, where R is 90mm, S is 7mm, L1 is 40mm, and L2 is 40mm. Then the wheel is put into an annular heating furnace at 860°C for heat preservation for 2.5h and then discharged from the furnace. After discharging, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upward, and 6 box-type nozzles evenly distributed along the circumferential direction of the wheel, as Figure 2 shown. The water column of the nozzle on the left side of the supporting roller is perpendicular to the tread of the wheel rim, and the water column of the nozzle on the right side of the supporting roller forms a 60° angle with the tangent of the tread. Each nozzle is distributed with weak-cooling water outlet holes and strong-cooling water outlet holes, and the water flow rate of each nozzle is equal. The water pressure is 0.1 ± 0.01MPa. The water output of the weak-cooling water outlet holes is 10m 3 / h, the spray quenching time is 80s, the water output of the strong-cooling water outlet holes is 24m 3 / h, and the strong-cooling spray quenching time is 320s. After quenching, the wheel is statically cooled in the air for 15min, and then the wheel is put into a tempering furnace with a furnace temperature of 480°C for tempering treatment. The tempering time is ≥4h, and after air cooling after discharging from the furnace, it is processed to the finished size.

[0076] Comparative Example 4

[0077] A production method of a blank wheel, specifically:

[0078] In this comparative example, the wheel steel used is of the same furnace number and specification as that in Example 4. The hot forming of the blank wheel is completed according to the production process of steel billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 1000mm (the outer diameter of the finished wheel is 970mm). During the rolling process, the tread of the blank wheel is rolled into Figure 1 the profile 1 in. Then the wheel is put into an annular heating furnace at 860°C for heat preservation for 2.5h and then discharged from the furnace. After discharging, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upward, and 6 box-type nozzles evenly distributed along the circumferential direction of the wheel. The water column of the nozzle forms a 45° angle with the tangent of the tread. Each nozzle is distributed with weak-cooling water outlet holes and strong-cooling water outlet holes, and the water flow rate of each nozzle is equal. The water pressure is 0.1 ± 0.01MPa. The water output of the weak-cooling water outlet holes is 10m 3 / h, the spray quenching time is 80s, the water output of the strong-cooling water outlet holes is 24m 3 / h, and the strong-cooling spray quenching time is 320s. After quenching, the wheel is put into a tempering furnace with a furnace temperature of 480°C for tempering treatment. The tempering time is ≥4h, and after air cooling after discharging from the furnace, it is processed to the finished size.

[0079] The hardness and microstructure of Example 4 and Comparative Example 4 were analyzed according to the requirements of BS EN 13262 "Railway applications - Wheelsets and bogies - Wheels - Product requirements". The hardness was measured according to GB / T 231.1 "Metallic materials - Brinell hardness test - Part 1: Test method", and the metallographic structure was detected according to GB / T 13298 "Metallic materials - Micrographic examination of the microstructure". The microstructure and the pearlite lamellar spacing law of Example 4 and Comparative Example 4 were basically the same as those of Example 1 and Comparative Example 1. The hardness of the wheel rims of Example 4 and Comparative Example 4 is as Figure 12 、 Figure 13 shown. As Figure 13 can be seen, for Example 4, whether it is 5 mm below the tread or 35 mm below the tread, as the distance from the inner rim surface increases, the hardness changes little; for Comparative Example 4, whether it is 5 mm below the tread or 35 mm below the tread, as the distance from the inner rim surface increases, the hardness changes significantly. It can be seen that adopting the profile solution of the present invention can significantly improve the hardness distribution of the microstructure of the wheel rim, especially improving the performance of the core part of the wheel rim.

[0080] Comparative Example 5

[0081] A production method of a blank wheel is as follows:

[0082] The wheel steel used in this comparative example is of the same heat number and specification as that of Example 4. The hot forming of the blank wheel is completed according to the production process of billet ingot cutting → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling. The outer diameter of the formed blank wheel is about 1000 mm (the outer diameter of the finished wheel is 970 mm). During the rolling process, the tread of the blank wheel is rolled into the Figure 1 profile 2. Then the wheel is put into an 860 °C ring heating furnace for heat preservation for 2.5 h and then discharged from the furnace. After discharging, quenching treatment is carried out. When quenching, the outer side of the wheel rim faces upwards, and 6 box-type nozzles are evenly distributed along the circumferential direction of the wheel. The water column of the nozzle forms an angle of 60° with the tangent of the tread, and the strong cooling method is used for quenching cooling. The water discharge of the strong cooling water outlet is 24 m 3 / h, and the strong cooling spray quenching time is 320 s. After quenching, the wheel is put into a tempering furnace with a furnace temperature of 480 °C for tempering treatment. The tempering time is ≥4 h, and after air cooling after discharging from the furnace, it is machined to the finished size.

[0083] The hardness and microstructure of Example 4 and Comparative Example 5 were analyzed according to the requirements of BS EN 13262 "Railway applications - Wheelsets and bogies - Wheels - Product requirements". The hardness was measured according to GB / T 231.1 "Metallic materials - Brinell hardness test - Part 1: Test method", and the metallographic structure was detected according to GB / T 13298 "Metallic materials - Micrographic examination of the microstructure". The hardness of the wheel rims of Example 4 and Comparative Example 5 is as Figure 12 、 Figure 14 shown. As Figure 14It can be seen that in Example 4, whether it is 5 mm below the tread or 35 mm below the tread, as the distance from the inner rim surface increases, the hardness change is not significant; in Comparative Example 5, the hardness at 35 mm below the tread is comparable to that in Example 4, but the hardness at 5 mm below the tread, especially at the nominal rolling circle, is significantly higher, seriously increasing the risk of abnormal microstructure and affecting the service performance.

[0084] The mechanical properties of the wheel rim parts of each example and comparative example were tested, and the results are shown in Table 2.

[0085] Table 2 Mechanical properties of the wheel rim parts of the examples and comparative examples

[0086]

[0087] According to Table 2, it can be obtained that by using Profile 2 of the present invention and the process of the present invention for production, the strength of the finished wheel is higher than that of the comparative example wheel, the elongation after fracture and the Charpy impact energy are comparable to those of the comparative example, and the performance meets the requirements of wheel operation.

[0088] The above detailed description of a blank wheel tread profile, controlled cooling method and its application for improving the performance of a wheel rim with reference to the examples and the drawings is illustrative rather than restrictive. Several examples can be listed within the defined scope. Therefore, changes and modifications within the general concept of the present invention should fall within the protection scope of the present invention.

Claims

1. A production method of a blank wheel for improving the performance of a wheel rim, characterized in that, The production method includes the following steps: 1) Hot forming of the blank wheel: ingot cutting of the steel billet → heating → descaling after furnace discharging → preforming → forming → rolling → punching → slow cooling; 2) After heating the wheel, quenching treatment is carried out with the outer side of the wheel facing upwards. The nozzles are evenly distributed along the circumferential direction of the wheel. For every two adjacent nozzles, one nozzle sprays the tread of the wheel vertically with water column, and the other nozzle sprays the tread of the wheel obliquely with water column; 3) Tempering treatment is carried out; For the rolling described in step 1), the tread profile of the blank wheel is controlled to be a concave tread profile; for the heating, the temperature is controlled at 1200 - 1280 °C; In step 2), for the heating, the heating temperature is 840 - 900 °C, and the heat preservation time is 2.5 - 3.5 h; on each nozzle, there are weak cooling water outlets and strong cooling water outlets, the water flow rate of each nozzle is equal, the water pressure is 0.1 ± 0.01 MPa, the water output of the weak cooling water outlet is 8 - 10 m 3 / h, and the water output of the strong cooling water outlet is 18 - 24 m 3 / h; the weak cooling water outlet conducts weak cooling spray quenching for 60 - 120 s, and the strong cooling water outlet conducts strong cooling spray quenching for 240 - 400 s; In step 3), after the quenched wheel is stationary in the air and cooled for 5 - 15 min, tempering treatment is carried out; the tempering treatment is: tempering treatment is carried out at 480 - 520 °C, and the tempering time ≥ 4 h.

2. A blank wheel for improving the performance of the wheel rim produced by the production method according to claim 1.

Images