Heavy-load wheel steel resistant to braking thermal damage, wheel, wheel production method and application

Abstract

The application provides a kind of anti-thermal damage heavy load wheel steel and wheel, wheel production method and application, composition: C 0.67-0.70%, Si 0.90-1.00%, Mn 0.80-0.90%, P≤0.015%, S 0.006-0.015%, V 0.05-0.15%, Cr 0.20-0.30%, N 0.0050-0.0100%, the rest is Fe and inevitable impurity element;Compared with prior art, by the reasonable control of C, Mn, Si, Cr, V element, the quenching heating temperature formula is designed, the heat treatment method of flow increment type quenching, constant flow quenching, obtains ideal fine pearlite + ferrite structure, not only the rim mechanical property level is higher, effectively improves the wear resistance of wheel, and improves the toughness of wheel, enhances the anti-thermal damage ability of wheel.

Description

Technical Field

[0001] This invention belongs to the field of wheel manufacturing, specifically relating to a heavy-duty wheel steel resistant to braking heat damage, a wheel, a wheel production method, and its application. It is used for the manufacture of railway freight wheels, especially for the manufacture of heavy-duty wheels with an axle load of 30t or more and an operating speed of 120km / h or less. Background Technology

[0002] Railway transportation occupies an extremely important position in the diversified global transportation system due to its unique advantages such as low cost, large capacity, high speed, low energy consumption, and environmental friendliness. Improving railway operation efficiency, alleviating freight pressure, and meeting the demands of economic development by increasing the axle load of freight cars is a new direction for the development of heavy-haul railway transportation.

[0003] Heavy-haul trains typically employ tread braking. Increased axle load intensifies the dynamic interaction between the wheel and rail, increasing the braking force required and consequently increasing the thermal effect of wheel braking. In emergencies, trains must reduce their speed to zero within a specified distance and time, resulting in a large and rapid heat input to the tread surface; this heat input is prolonged when braking on long gradients. Frictional heat causes a rise in wheel tread temperature, creating a significant temperature gradient and generating a thermal stress field that fluctuates. If the thermal load worsens, it can potentially lead to wheel failure, directly impacting wheel life and operational safety.

[0004] Currently, the TB / T 2817 standard specifies CL60 (II steel), CL65 (III steel), and CL70 (IV steel), but none of these specify the fracture toughness of the wheel rim. The European standard EN13262 stipulates that the maximum carbon content of wheels cannot exceed 0.60%, which is detrimental to heavy-duty service conditions. The American standard AAR M-107 / M-208 specifies three materials: AAR-B, AAR-C, and AAR-D, but does not specify impact performance.

[0005] After retrieval, the Chinese invention patent "Steel for High-strength and High-toughness Heavy-haul Train Wheels and Its Heat Treatment Method" with the publication number CN106521315A, which was publicly disclosed on March 22, 2017, discloses that its chemical composition by weight percentage (wt.%) is: C: 0.75 - 0.85 wt.%, Si: 0.80 - 1.00 wt.%, Cr: 0.40 - 0.80 wt.%, Mn: 0.30 - 0.50 wt.%, Nb: 0.01 - 0.03 wt.%, V: 0.02 - 0.06 wt.%, Al: 0.010 - 0.025 wt.%, P: <0.015 wt.%, S: <0.015 wt.%, and the balance is Fe and unavoidable impurities, all in weight percentages. After conventional smelting, casting, and forging and rolling, the wheels are subjected to a new heat treatment process method of tread quenching and segmented cooling. After heat treatment, the structure at the standard tensile test position of the wheel rim is fully lamellar pearlite structure, the pearlite colony size is 2 - 6 μm, and the pearlite lamellar spacing is 0.05 - 0.09 μm. The tensile strength of the wheel rim at room temperature is at the 1200 MPa level, the elongation after fracture is greater than 12%, the impact energy KU2 of the web at 20 °C is greater than 20 J, and it has excellent strength and toughness matching. Its existing technical defect is that the upper limit of the C content of 0.85% exceeds the upper limit of the C content of 0.77% of domestic CL70 material and North American AAR-C material wheels, and does not meet the standard requirements.

[0006] The Chinese invention patent "Preparation Method of High-carbon Steel Wheels for Railway Freight Cars with Improved Plasticity" with the publication number CN 103741033 A, which was publicly disclosed on April 23, 2014, discloses that its chemical composition by weight percentage is: C 0.70 - 0.75%, Si 0.70 - 1.00%, Mn 0.60 - 0.90%, 0 <Cr ≤ 0.35%, Als 0.010 - 0.030%, P ≤ 0.020%, S ≤ 0.040%, and the rest are Fe and unavoidable impurity elements. The heat treatment process is: the wheels after rolling and rough machining are heated in the furnace to 850 - 880 °C and then held for a total heating time of 2.5 - 3.0 h, and then taken out of the furnace and air-cooled to room temperature; then the wheels are heated in the furnace to 840 - 860 °C and held for a total heating time of 2.5 - 3.0 h, and then taken out of the furnace and sprayed with water to cool for 450 s; then put into a furnace at 490 - 510 °C, held for 4.5 - 5.5 h, and then taken out of the furnace and air-cooled to room temperature to obtain good comprehensive performance. The disadvantage is that compared with the conventional quenching process, an additional normalizing process of heating → air-cooling is added, increasing greenhouse gas emissions and being not environmentally friendly. Summary of the Invention

[0007] The purpose of this invention is to provide a heavy-duty wheel steel resistant to braking thermal damage. By rationally controlling the elements C, Mn, Si, Cr, and V, a composition design formula is proposed. The wheel that meets the composition design has a significantly improved Ac3 point and a significantly reduced Ms point. Furthermore, a relationship between the quenching heating temperature and the V element content to ensure the comprehensive performance of the wheel is proposed. The wheel that meets the relationship design for the quenching heating temperature not only has better comprehensive mechanical properties, but also has a significantly improved resistance to thermal damage.

[0008] Another objective of this invention is to provide a wheel and a wheel manufacturing method. The wheel is manufactured using the aforementioned heavy-duty wheel steel resistant to braking heat damage. Based on the composition characteristics, a matching production process and parameters are designed so that the produced wheel, compared with traditional AAR-C wheel steel, not only has a higher level of rim mechanical properties and significantly improved wheel strength, effectively enhancing the wear resistance of the wheel under heavy-duty service conditions, but also improves wheel toughness, enhances the wheel's resistance to braking heat damage under heavy-duty service conditions, and provides greater safety redundancy in wheel design.

[0009] Another objective of this invention is to provide an application for wheels used in the manufacture of heavy-haul railway freight cars with an axle load of 30t or more and an operating speed of 120km / h or less.

[0010] The specific technical solution of this invention is as follows:

[0011] A heat-damage resistant heavy-duty wheel steel comprises the following components by weight percentage:

[0012] C 0.67-0.70%, Si 0.90-1.00%, Mn 0.80-0.90%, P≤0.015%, S 0.006-0.015%, V 0.05-0.15%, Cr 0.20-0.30%, N 0.0050-0.0100%, with the remainder being Fe and unavoidable impurity elements.

[0013] The composition of the heat-damage resistant heavy-duty wheel steel also satisfies: 425 < A value < 445; the A value = 930 - [570 × % C] - [80 × % Mn] - [20 × % Si] - [50 × % Cr] - [20 × % V]. This formula is based on the composition design of AAR M-107 / M-208 "Carbon Steel Wheel Specification". However, the AAR standard only requires the formula value to be > 390, while this invention specifies upper and lower limits. On the one hand, this is to consider the matching of strength and toughness, and on the other hand, it is to consider that excessively high content of strengthening elements is detrimental to the heat damage resistance.

[0014] In the calculation formula, the index value of each element = the content of that element in the steel × 100.

[0015] The present invention provides a wheel, which is produced using the above-mentioned heat-damage resistant heavy-duty wheel steel.

[0016] The tensile properties of the wheel are: tensile strength Rm≥1190MPa, elongation A 50 ≥15%; hardness at 38.1mm below the tread surface ≥330HB, room temperature impact performance U5≥11J, -60℃ impact performance U 5,2 ≥40J, fracture toughness ≥48.6MPa·m 1 / 2 The depth of the abnormal tissue on the wheel is ≤3.0mm.

[0017] The thermal damage resistance of the wheels was evaluated according to industry standard HB6660-2011. The thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was circulating water at room temperature. At 400℃, the average crack length was ≤0.33mm, and at 650℃, the average crack length was ≤1.02mm.

[0018] The present invention provides a method for producing wheels, including a heat treatment process;

[0019] The heat treatment process includes: quenching heating, flow-increment quenching, constant flow quenching, and tempering.

[0020] The quenching heating temperature is T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 The quenching heating time is 2.5-3.0 h; where T is the quenching heating temperature, °C; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V element content accounts for about 20% of the total V content. On the one hand, it ensures the precipitation strengthening effect of V element, and on the other hand, it controls the precipitated V content within a certain range to avoid a decrease in overall performance due to excessive V precipitation. The precipitated V combines with C and N elements in the wheel to form compounds, which play a role in fine grain strengthening, ensuring both wheel strength and high toughness. The V element content can be simulated using Thermo-Calc thermodynamic calculation software.

[0021] After quenching and heating to homogenize the austenite, the wheel is placed on a quenching platform with six evenly distributed water nozzles. Two stages of water-cooled quenching are then performed, both on the tread surface, with no time interval between them. Specifically, the incremental flow quenching is as follows: In the first stage, all six water nozzles, evenly distributed at 60° intervals, are opened, and quenching is performed for time t1. The nozzle pressure is kept constant at 0.10 ± 0.02 MPa. The nozzle system module is set to y1 = 17 + 0.05t1, where the maximum value of t1 is t...1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle in the first stage, in meters. 3 / h; D is the rolled wheel rim thickness, mm; t1 is the first stage quenching time, in seconds; the nozzle flow rate gradually increases because the wheel quenching method is tread surface water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, it is not necessary to have an excessively high cooling rate. The advantage of doing so is that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layer, reducing subsequent machining allowances, which is beneficial to improving yield and reducing costs and increasing efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layer has been completed, while the cooling rate inside the wheel rim is limited, so the flow rate increases with time.

[0022] After the first stage of quenching (incremental flow rate quenching) is completed, the second stage of quenching (constant flow rate quenching) is carried out directly until the end;

[0023] Constant flow quenching is performed by closing one nozzle outlet panel every 120°, i.e., opening three evenly distributed nozzles for quenching. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set with y2=25 and t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle in the second stage, in meters. 3 / h; D is the thickness of the rolled wheel rim, mm; t2 is the second-stage quenching time, in seconds;

[0024] There is no pause between the first and second stages of quenching. Constant flow is used after the first stage because the microstructure within the tread and 20mm below the tread has already completed its transformation. Constant flow does not affect the microstructure within the 20mm below the tread and can radiate enough cooling capacity into the rim. At the same time, it can prevent heat from the spokes and the transition between the spokes from being transferred into the rim and affecting the microstructure transformation.

[0025] After quenching, tempering is performed at 500±10℃ for 4.0±0.5 hours.

[0026] When using the above formulas, simply substitute the numerical value before the unit into the formula.

[0027] The present invention provides an application of a wheel, wherein the wheel produced by the above method is used in the manufacture of heavy-haul railway freight cars with an axle load of 30t or more and an operating speed of 120km / h or less.

[0028] The design concept of this invention is as follows:

[0029] To date, the steel used for heavy-duty freight wheels both domestically and internationally is high-carbon steel with a ferritic + pearlitic structure. Wheels with this structure have the best wear resistance when the hardness level is comparable. Therefore, the wheel steel of the present invention has a ferritic + pearlitic structure.

[0030] Carbon (C) is the primary strengthening element in wheel steel. Heavy-duty truck wheels have a ferrite-pearlite microstructure. Based on the relationship between ferrite-pearlite microstructure and properties, increasing carbon content can improve strength and hardness, but it compromises toughness. Reducing carbon content is the most feasible way to ensure toughness. Looking at mainstream wheel standards worldwide, including Chinese, European, Japanese, and American standards, the lower limit for carbon content in heavy-duty wheels exceeds 0.67%, while the upper limit is below 0.77%. Therefore, this invention sets the carbon content range at 0.67-0.70%, thereby achieving a better balance between strength and toughness and effectively improving the heat damage resistance of the wheel material.

[0031] Si is a ferrite-forming element. Adding Si can increase the phase transformation point of steel when the carbon content is reduced, without significantly altering the material's plasticity. This can compensate for the strength loss caused by reducing carbon content, resulting in better wear resistance. Furthermore, it can prevent microstructural transformation during heating or cooling, effectively improving the wheel material's resistance to thermal damage. However, excessively high Si content can reduce the steel's toughness and plasticity to some extent; therefore, this invention defines the Si content as 0.90-1.00%.

[0032] Mn is adjacent to iron in the periodic table, and γ-Mn has a face-centered cubic structure, similar to austenite, primarily functioning as a solid solution strengthener. It can also lower the γ-α transformation temperature, refine ferrite grains, and alter the microstructure after phase transformation, thus improving the strength of the steel. However, excessively high Mn content significantly lowers the phase transformation point of the wheel, negatively impacting its resistance to heat damage; therefore, its content must be limited. Furthermore, Mn has a strong affinity for sulfur, preventing the formation of low-melting-point sulfides (FeS) at grain boundaries, instead allowing it to exist as MnS with a certain degree of plasticity, thereby eliminating the harmful effects of sulfur and improving the hot workability of the steel. A high Mn / S ratio can improve the plasticity and toughness of wheel steel, but it increases overheat sensitivity and temper brittleness. Therefore, this invention defines the Mn content range as 0.80-0.90% and the S content range as 0.006-0.015%.

[0033] Phosphorus (P) is a ferrite stabilizing element. P dissolves in ferrite, increasing the strength and hardness of wheel steel; however, severe segregation reduces the steel's plasticity and toughness, making wheels prone to brittle fracture during processing. Therefore, this invention controls the P content to ≤0.015%.

[0034] Vanadium (V) has low solubility in steel and a weak effect on austenite grain growth and recrystallization inhibition. However, vanadium carbonitrides have a relatively low precipitation temperature and promote ferrite nucleation, forming numerous finely dispersed vanadium carbonitrides within the ferrite, resulting in precipitation strengthening. Furthermore, vanadium carbonitrides possess high thermal stability, effectively pinning dislocations and improving the strength of wheel steel during high-temperature applications such as braking. However, excessively high V and N content can overly increase wheel strength, negatively impacting ductility and toughness. Therefore, this invention defines the V content range as 0.05-0.15% and the N content range as 0.0050-0.0100%.

[0035] Chromium (Cr) is a carbide-forming element and a common alloying element in steel. It readily occupies nodal sites in the α-Fe crystal lattice to form substitutional solid solutions. Adding an appropriate amount of chromium to carbon steel can significantly improve its tensile strength and yield strength. However, high chromium content can lead to carbide coarsening, significantly reducing the plasticity and toughness of wheels. Therefore, this invention controls the chromium content to 0.20-0.30%.

[0036] Compared with existing technologies, this invention proposes a composition design formula through the rational control of C, Mn, Si, Cr, and V elements. This formula significantly improves the Ac3 point and significantly reduces the Ms point of the wheel, resulting in superior overall mechanical properties and a markedly improved resistance to thermal damage. The invention also designs a relationship between quenching temperature and V element content, ensuring the precipitation strengthening effect of V while controlling the V content within a certain range to avoid a decline in overall performance due to excessive V precipitation. During heat treatment, a flow-increase quenching process is employed to obtain an ideal fine pearlite + ferrite microstructure. This not only results in higher mechanical properties of the rim and effectively improves the wheel's wear resistance but also enhances its toughness and resistance to thermal damage. Compared with traditional AAR-C series heavy-duty wheel steel, the wheel of this invention not only has superior hardness but also significantly improved toughness, enhancing its resistance to thermal damage under service conditions. Attached Figure Description

[0037] Figure 1 The rim structure is shown in Example 1;

[0038] Figure 2 Example 2: Rim structure;

[0039] Figure 3 Example 3: Rim structure;

[0040] Figure 4 Example 4: Rim structure;

[0041] Figure 5Example 5 shows the rim structure;

[0042] Figure 6 Example 6: Rim structure;

[0043] Figure 7 For the rim structure of Comparative Example 1;

[0044] Figure 8 For comparison, the rim structure of wheel example 2;

[0045] Figure 9 For comparison, the rim structure of wheel 3 is shown;

[0046] Figure 10 For comparison, the rim structure of four wheels is shown.

[0047] Figure 11 For comparison, the rim structure of wheel 5 is shown;

[0048] Figure 12 For comparison, the rim structure of wheel 6 is shown;

[0049] Figure 13 For comparison, the rim structure of wheel 7 is shown;

[0050] Figure 14 For comparison, the rim structure of wheel 8 is shown;

[0051] Figure 15 For comparison of the depth of abnormal tissue in each embodiment and comparative example;

[0052] Figure 16 A comparison of the cross-sectional hardness of each embodiment and comparative example;

[0053] Figure 17 A comparison of the AC3-point temperatures of each embodiment and comparative example;

[0054] Figure 18 For comparison of the Ms point temperatures of each embodiment and comparative example;

[0055] Figure 19 Comparison of average crack lengths. Detailed Implementation

[0056] The present invention will now be described in detail with reference to the accompanying drawings, embodiments, and comparative examples.

[0057] Examples 1-6

[0058] A heat-damage resistant heavy-duty wheel steel comprises the following composition by mass percentage as shown in Table 1, where the balance not shown in Table 1 is Fe and unavoidable impurities.

[0059] Comparative Examples 1-8

[0060] A wheel steel comprising the following composition by mass percentage as shown in Table 1, with the balance not shown in Table 1 being Fe and unavoidable impurities.

[0061] Table 1. Chemical composition (mass percentage%) of the wheels used in Examples 1, 2, 3, and the comparative examples.

[0062]

[0063]

[0064] The methods for producing wheels from wheel steel in the above embodiments and comparative examples include electric furnace smelting, direct continuous casting into φ450mm round billets after LF+RH refining and vacuum degassing, and then ingot cutting, heating and rolling, and heat treatment processes to form wheels with a diameter of 970mm and different rim thicknesses.

[0065] The specific methods for producing wheels in each embodiment and comparative example are as follows:

[0066] Example 1

[0067] The molten steel with the chemical composition shown in Table 1 (Example 1) is processed through an electric arc furnace steelmaking process, an LF furnace refining process, an RH vacuum treatment process, a round billet continuous casting process, a hot rolling process for ingot cutting, a heat treatment process, a machining process, and a finished product inspection process. The heat treatment process is performed using the empirical formula: T = 820 + 791.7 × ω(V) - 2083.3 × ω(V) 2 In the formula, T is the quenching heating temperature, ℃; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V content accounts for about 20% of the total V content; T is determined to be 892℃. Considering the stability of on-site operation, the wheel is heated to 885-895℃ with the furnace and held for 3.0 hours. After exiting the furnace, a flow-increase quenching method (first stage quenching) is adopted. First, the nozzle pressure is kept constant at 0.10±0.02MPa, and 6 evenly distributed water spray panels are turned on for quenching at time t1. The nozzle system module is set to y1=17+0.05t1, t 1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle, in meters. 3 / h; D is taken as 83mm for the rolled wheel rim thickness, and the time coefficient is taken as 1.5, t 1max=124.5s. The nozzle flow rate gradually increases because the wheel quenching method is tread surface water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, an excessively high cooling rate is not required. The advantages of this are that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layer, reducing subsequent machining allowances, which is beneficial to improving yield and reducing costs and increasing efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layer has been completed, while the cooling rate inside the rim is limited, so the flow rate increases with time. After 124.5s, constant flow quenching (second stage quenching) is adopted, and one nozzle water outlet panel is closed at 120° intervals, that is, the three evenly distributed nozzles are opened for constant water flow quenching. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set as y2=25, t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle, m 3 / h; t2=2.5×D=207.5s. There is no pause between the first and second stages. Constant flow rate is used after the first stage because the microstructure of the tread and the area within 20mm below the tread has completed its transformation. Constant flow rate does not affect the area within 20mm below the tread and can radiate sufficient cooling capacity into the rim. At the same time, it can prevent heat from the spokes and the transition area between the spokes from being transferred into the rim and affecting the microstructure transformation. Finally, tempering is performed at 500±10℃ for 4.0 hours.

[0068] like Figure 1 , 7 As shown in Tables 1, 13, 15, 16 and 2, the metallographic structure of the wheel rim prepared in this embodiment is the same as that of the wheels in Comparative Examples 1 and 7, consisting of fine pearlite and a small amount of ferrite, with no significant difference. However, the tensile properties and the cross-sectional hardness at 38.1 mm below the tread of the wheel in this embodiment are significantly higher than those of the wheels in Comparative Examples 1 and 7; the fracture toughness is significantly higher than that of the wheel in Comparative Example 1, slightly lower than that of the wheel in Comparative Example 7, but still at a high level; and the depth of abnormal structures is significantly smaller than that of the wheels in Comparative Examples 1 and 7.

[0069] Comparative wear tests at room temperature and low temperature were conducted on a rolling contact fatigue test bench. The low-temperature rolling wear test involved adding a low-temperature environment system (connected to a refrigeration unit and a PID control system via a low-temperature chamber) to the test bench. The rolling wear test specimens were 40mm disc-shaped samples, all taken from the same location on the rim of the wheels in the comparative examples and this embodiment. The test results are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the wear performance of the wheel in Example 1 at room temperature and -40℃ is significantly better than that of the wheels in Comparative Examples 1 and 7.

[0070] According to the empirical formula Ac3(°C) = 910 - 203°C 0.5-15.2Ni+44.7Si+104V+31.5Mo+13.1W and Ms(°C)=561-474C-33Mn-17Cr-17Ni-21Mo, the Ac3 point and Ms point of the wheels in this embodiment and the comparative example were calculated, and the results are shown in the figure. Figures 17-18 And as shown in Table 5. From Figures 17-18 As shown in Table 5, the Ac3 point of the wheel in Example 1 is significantly higher than that of the wheel in Comparative Example 7, and the Ms point is significantly lower than that of the wheel in Comparative Example 7. This makes it less likely for the wheel to undergo structural transformation when heated or cooled, and can effectively improve the wheel's resistance to heat damage.

[0071] According to industry standard HB6660--2011, the thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine to evaluate thermal damage performance. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was room temperature circulating water. Thermal fatigue specimens were taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in [Figure number missing]. Figure 19 And as shown in Table 5. From Figure 19 As can be seen from Table 5, the thermal fatigue crack length of the wheel in Example 1 at different cycling temperatures is significantly shorter than that of the wheels in Comparative Example 1 and Comparative Example 7.

[0072] Therefore, it can be seen that, while maintaining a high level of toughness, the wheel of Example 1 exhibits superior tensile properties and hardness compared to the wheels of Comparative Example 1 and Comparative Example 7, while showing significantly improved wear resistance at room temperature and -40℃, and a significantly shorter thermal fatigue crack length. Compared to the wheel of Comparative Example 7, the wheel of Example 1 shows a significantly higher Ac3 temperature and a lower Ms temperature. The optimized composition design, coupled with the flow-increasing quenching heat treatment process, results in superior overall mechanical properties and resistance to thermal damage for the wheel of Example 1.

[0073] Example 2

[0074] The molten steel with the chemical composition shown in Table 1 (Example 2) is processed through an electric arc furnace steelmaking process, an LF furnace refining process, an RH vacuum treatment process, a round billet continuous casting process, a hot rolling process for ingot cutting, a heat treatment process, a machining process, and a finished product inspection process. The heat treatment process is performed using the empirical formula: T = 820 + 791.7 × ω(V) - 2083.3 × ω(V) 2In the formula, T is the quenching heating temperature, ℃; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V content accounts for about 20% of the total V content; T is determined to be 870℃. Considering the stability of on-site operation, the wheel is heated to 865-875℃ with the furnace and held for 2.8 hours. After exiting the furnace, a flow-increase quenching method (first stage quenching) is adopted. First, the nozzle pressure is kept constant at 0.10±0.02MPa, and 6 evenly distributed water spray panels are turned on for quenching at time t1. The nozzle system module is set to y1=17+0.05t1, t 1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle, in meters. 3 / h; D is taken as 85mm for the rolled wheel rim thickness, and the time coefficient is taken as 1.5, t 1max =127.5s. The nozzle flow rate gradually increases because the wheel quenching method is tread surface water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, an excessively high cooling rate is not required. The advantages of this are that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layers, reducing subsequent machining allowances and benefiting the improvement of yield and cost reduction and efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layers has been completed, while the cooling rate inside the rim is limited, so the flow rate increases with time. After 127.5s, constant flow quenching (second stage quenching) is adopted, and one nozzle water outlet panel is closed at 120° intervals for constant water flow quenching, that is, three nozzles are closed, and the open nozzles are spaced 120° apart. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set as y2=25, t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle, m 3 / h; t2=2.5×D=212.5s. There is no pause between the first and second stages. Constant flow rate is used after the first stage because the microstructure within the tread and 20mm below the tread has completed its transformation. Constant flow rate does not affect the microstructure within the 20mm below the tread and can radiate sufficient cooling capacity into the rim interior. At the same time, it can prevent heat from the spokes and the transition area between the spokes from being transferred into the rim interior and affecting the microstructure transformation. Finally, tempering treatment is carried out at 500±10℃ for 4.0 hours.

[0075] like Figure 2 , 8As shown in 14, 15, 16 and Table 2, the metallographic structure of the wheel rim prepared in this embodiment is the same as that of the wheels of Comparative Example 2 and Comparative Example 8, which is fine pearlite with a small amount of ferrite, with no significant difference. However, the tensile properties and the cross-sectional hardness at 38.1 mm below the tread of the wheel in this embodiment are comparable to those of the wheel of Comparative Example 2, and significantly higher than those of the wheel of Comparative Example 8. The fracture toughness is higher than that of the wheel of Comparative Example 2, slightly lower than that of the wheel of Comparative Example 8, but still at a high level. The depth of abnormal structure is significantly smaller than that of the wheels of Comparative Example 2 and Comparative Example 8.

[0076] Comparative wear tests at room temperature and low temperature were conducted on a rolling contact fatigue test bench. The low-temperature rolling wear test involved adding a low-temperature environment system (connected to a refrigeration unit and a PID control system via a low-temperature chamber) to the test bench. The rolling wear test specimens were 40mm disc-shaped specimens, all taken from the same location on the rim of the wheels in the comparative examples and this embodiment. The test results are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the wear performance of the wheel in Example 2 at room temperature and -40℃ is significantly better than that of the wheels in Comparative Examples 2 and 8.

[0077] According to the empirical formula Ac3(°C) = 910 - 203°C 0.5 -15.2Ni+44.7Si+104V+31.5Mo+13.1W and Ms(°C)=561-474C-33Mn-17Cr-17Ni-21Mo, the Ac3 point and Ms point of the wheels in this embodiment and the comparative example were calculated, and the results are shown in the figure. Figures 17-18 And as shown in Table 5. From Figures 17-18 As shown in Table 5, the Ac3 point of the wheel in Example 2 is significantly higher than that of the wheel in Comparative Example 8, and the Ms point is significantly lower than that of the wheel in Comparative Example 8. This makes it less likely for the wheel to undergo structural transformation when heated or cooled, and can effectively improve the wheel's resistance to heat damage.

[0078] According to industry standard HB6660--2011, the thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine to evaluate thermal damage performance. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was room temperature circulating water. Thermal fatigue specimens were taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in [Figure number missing]. Figure 19 And as shown in Table 5. From Figure 19 As can be seen from Table 5, the thermal fatigue crack length of the wheel in Example 2 is significantly shorter than that of the wheels in Comparative Example 2 and Comparative Example 8 under different cycling temperatures.

[0079] Therefore, it can be seen that, while maintaining a high level of toughness, the wheel of Example 2 exhibits tensile properties and cross-sectional hardness comparable to that of Comparative Example 2, and its strength is significantly superior to that of Comparative Example 8. Furthermore, its wear resistance at room temperature and -40℃ is significantly improved, and the thermal fatigue crack length is significantly shorter. Compared to Comparative Example 8, the wheel of Example 2 shows a significantly higher Ac3 temperature and a lower Ms temperature. The optimized composition design, coupled with a flow-increase quenching heat treatment process, results in superior overall mechanical properties and resistance to thermal damage for the wheel of Example 2.

[0080] Example 3

[0081] The molten steel with the chemical composition shown in Table 1 (Example 3) is processed through an electric arc furnace steelmaking process, an LF furnace refining process, an RH vacuum treatment process, a round billet continuous casting process, a hot rolling process for ingot cutting, a heat treatment process, a machining process, and a finished product inspection process. The heat treatment process is performed using the empirical formula: T = 820 + 791.7 × ω(V) - 2083.3 × ω(V) 2 In the formula, T is the quenching heating temperature, ℃; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V content accounts for about 20% of the total V content. T is determined to be 885℃. Considering the stability of on-site operation, the wheel is heated to 880-890℃ with the furnace and held for 2.7 hours. After being taken out of the furnace, a flow-increase quenching method (first stage quenching) is adopted. First, the nozzle pressure is kept constant at 0.10±0.02MPa, and 6 evenly distributed water spray panels are turned on for quenching at time t1. The nozzle system module is set to y1=17+0.05t1, t 1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle, in meters. 3 / h; D is taken as 75mm for the rolled wheel rim thickness, and the time coefficient is taken as 1.6, t 1max =120s. The nozzle flow rate gradually increases because the wheel quenching method is tread surface water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, an excessively high cooling rate is not required. The advantages of this are that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layer, reducing subsequent machining allowances, which is beneficial to improving yield and reducing costs and increasing efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layer has been completed, while the cooling rate inside the rim is limited, so the flow rate increases with time. After 120s, constant flow quenching (second stage quenching) is adopted, and the water outlet panels of the three nozzles are closed at 120° intervals for constant water flow quenching. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set as y2=25, t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle, m 3 / h; t2=2.8×D=210s. There is no pause between the first and second stages. Constant flow rate is used after the first stage because the microstructure of the tread and the area within 20mm below the tread has completed the microstructure transformation. Constant flow rate does not affect the area within 20mm below the tread and can radiate enough cooling capacity into the rim. At the same time, it can prevent the heat from the spokes and the transition area between the spokes from being transferred into the rim and affecting the microstructure transformation. Finally, tempering treatment is carried out at 510±10℃ for 4.0 hours.

[0082] like Figure 3 , 9 As shown in Tables 15, 16 and 2, the metallographic structure of the wheel rim prepared in this embodiment is the same as that of the wheel in Comparative Example 3, which is fine pearlite with a small amount of ferrite. There is no significant difference, and the impact toughness is comparable. However, the tensile properties and the cross-sectional hardness at 38.1 mm below the tread of the wheel in this embodiment are significantly higher than those of the wheel in Comparative Example 3. The fracture toughness is better than that of the wheel in Comparative Example 3, and the depth of abnormal structure is smaller than that of the wheel in Comparative Example 3.

[0083] Comparative wear tests at room temperature and low temperature were conducted on a rolling contact fatigue test bench. The low-temperature rolling wear test involved adding a low-temperature environment system (connected to a refrigeration unit and a PID control system via a low-temperature chamber) to the test bench. The rolling wear test specimens were 40mm disc-shaped samples, all taken from the same location on the rim of the wheels in the comparative example and this embodiment. The test results are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the wear performance of the wheel in Example 3 at both room temperature and -40℃ is significantly better than that of the wheel in Comparative Example 3.

[0084] According to industry standard HB6660--2011, the thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine to evaluate thermal damage performance. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was room temperature circulating water. Thermal fatigue specimens were taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in [Figure number missing]. Figure 19 And as shown in Table 5. From Figure 19 As can be seen from Table 5, the thermal fatigue crack length of the wheel in Example 3 is significantly shorter than that of the wheel in Comparative Example 3 under different cycling temperatures.

[0085] Therefore, it can be seen that, under the premise of comparable impact performance and superior tensile properties, hardness, and fracture toughness compared to the wheel of Comparative Example 3, the wear resistance at room temperature and -40℃ is significantly improved, and the thermal fatigue crack length is significantly shorter. The optimized composition design, coupled with the heat treatment process of the flow-increase quenching method, makes the wheel of Example 3 have better overall mechanical properties and resistance to thermal damage.

[0086] Example 4:

[0087] The molten steel with the chemical composition shown in Table 1 (Example 4) is processed through an electric arc furnace steelmaking process, an LF furnace refining process, an RH vacuum treatment process, a round billet continuous casting process, a hot rolling process for ingot cutting, a heat treatment process, a machining process, and a finished product inspection process. The heat treatment process is performed using the empirical formula: T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 In the formula, T is the quenching heating temperature, ℃; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V content accounts for about 20% of the total V content. T is determined to be 890℃. Considering the stability of on-site operation, the wheel is heated to 885-895℃ with the furnace and held for 2.9 hours. After exiting the furnace, a flow-increase quenching method (first stage quenching) is adopted. First, the nozzle pressure is kept constant at 0.10±0.02MPa, and 6 evenly distributed water spray panels are turned on for quenching at time t1. The nozzle system module is set to y1=17+0.05t1, t 1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle, in meters. 3 / h; D is taken as 55mm for the rolled wheel rim thickness, and the time coefficient is taken as 1.8, t 1max =99s. The nozzle flow rate gradually increases because the wheel quenching method is tread water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, an excessively high cooling rate is not required. The advantages of this are that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layer, reducing subsequent machining allowances, which is beneficial to improving yield and reducing costs and increasing efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layer has been completed, while the cooling rate inside the rim is limited, so the flow rate increases with time. After 99s, constant flow quenching (second stage quenching) is adopted, and the water outlet panels of the three nozzles are closed at 120° intervals for constant water flow quenching. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set as y2=25, t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle, m 3 / h; t2=3.0×D=165s. There is no pause between the first and second stages. Constant flow rate is used after the first stage because the microstructure of the tread and the area within 20mm below the tread has completed the microstructure transformation. Constant flow rate does not affect the area within 20mm below the tread and can radiate enough cooling capacity into the rim. At the same time, it can prevent the heat from the spokes and the transition between the spokes from being transferred to the rim and affecting the microstructure transformation. Finally, tempering is performed at 500℃ for 4.0 hours.

[0088] like Figure 4 , 10As shown in Tables 15, 16 and 2, the metallographic structure of the wheel rim prepared in this embodiment is fine pearlite with a small amount of ferrite, and there is no significant difference. The impact toughness, tensile properties, and cross-sectional hardness at 38.1 mm below the tread are comparable. The fracture toughness is significantly higher than that of the wheel in Comparative Example 4, and the depth of abnormal structure is significantly smaller than that of the wheel in Comparative Example 4.

[0089] Comparative wear tests at room temperature and low temperature were conducted on a rolling contact fatigue test bench. The low-temperature rolling wear test involved adding a low-temperature environment system (connected to a refrigeration unit and a PID control system via a low-temperature chamber) to the test bench. The rolling wear test specimens were 40mm disc-shaped samples, all taken from the same location on the rim of the wheels in the comparative example and this embodiment. The test results are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the wear performance of the wheel in Example 4 at both room temperature and -40℃ is significantly better than that of the wheel in Comparative Example 4.

[0090] According to industry standard HB6660--2011, the thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine to evaluate thermal damage performance. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was room temperature circulating water. Thermal fatigue specimens were taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in [Figure number missing]. Figure 19 And as shown in Table 5. From Figure 19 As can be seen from Table 5, the thermal fatigue crack length of the wheel in Example 4 is significantly shorter than that of the wheel in the comparative example under different cycling temperatures.

[0091] Therefore, it can be seen that the wheel of Example 4, while having comparable impact performance, tensile properties, and hardness to Comparative Example 4, and superior fracture toughness compared to Comparative Example 4, exhibits significantly improved wear resistance at room temperature and -40℃, and a significantly shorter thermal fatigue crack length. The optimized composition design, coupled with a flow-increase quenching heat treatment process, results in superior overall mechanical properties and resistance to thermal damage for the wheel of Example 4, demonstrating that the invention has achieved its intended effects.

[0092] Example 5

[0093] The molten steel with the chemical composition shown in Table 1 (Example 5) is processed through an electric arc furnace steelmaking process, an LF furnace refining process, an RH vacuum treatment process, a round billet continuous casting process, a hot rolling process for ingot cutting, a heat treatment process, a machining process, and a finished product inspection process. The heat treatment process is performed using the empirical formula: T = 820 + 791.7 × ω(V) - 2083.3 × ω(V) 2In the formula, T is the quenching heating temperature, ℃; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V content accounts for about 20% of the total V content; T is determined to be 854℃. Considering the stability of on-site operation, the wheel is heated to 850-860℃ with the furnace and held for 3.0 hours. After exiting the furnace, a flow-increase quenching method (first stage quenching) is adopted. First, the nozzle pressure is kept constant at 0.10±0.02MPa, and 6 evenly distributed water spray panels are turned on for quenching at time t1. The nozzle system module is set to y1=17+0.05t1, t 1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle, in meters. 3 / h; D is taken as 75mm for the rolled wheel rim thickness, and the time coefficient is taken as 1.5, t 1max =112.5s. The nozzle flow rate gradually increases because the wheel quenching method is tread surface water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, an excessively high cooling rate is not required. The advantages of this are that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layers, reducing subsequent machining allowances, which is beneficial to improving yield and reducing costs and increasing efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layers has been completed, while the cooling rate inside the rim is limited, so the flow rate increases with time. After 112.5s, constant flow quenching (second stage quenching) is adopted, and the water outlet panels of the three nozzles are closed at 120° intervals for constant water flow quenching. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set as y2=25, t2=(2.5-3)×D, where y is the flow rate of a single nozzle, m 3 / h; t2=2.5×D=187.5s. There is no pause between the first and second stages. Constant flow is used after the first stage because the microstructure within the tread and 20mm below the tread has completed its transformation. Constant flow does not affect the microstructure within the 20mm below the tread and can radiate sufficient cooling capacity into the rim interior. At the same time, it can prevent heat from the spokes and the transition area between the spokes from being transferred into the rim interior and affecting the microstructure transformation. Finally, tempering is performed at 500±10℃ for 4.0 hours.

[0094] like Figure 5 , 11 As shown in Tables 15, 16 and 2, the metallographic structure of the wheel rim prepared in this embodiment is fine pearlite plus a small amount of ferrite, with no significant difference from that of the wheel in Comparative Example 5. The impact toughness and tensile properties are comparable. The hardness and fracture toughness of the cross section at 38.1 mm below the tread are significantly higher than those of the wheel in Comparative Example 5, and the depth of abnormal structure is significantly smaller than that of the wheel in Comparative Example 5.

[0095] Comparative wear tests at room temperature and low temperature were conducted on a rolling contact fatigue test bench. The low-temperature rolling wear test involved adding a low-temperature environment system (connected to a refrigeration unit and a PID control system via a low-temperature chamber) to the test bench. The rolling wear test specimens were 40mm disc-shaped specimens, all taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the wear performance of the wheel of Example 5 at both room temperature and -40℃ is significantly better than that of the wheel of Comparative Example 5.

[0096] According to industry standard HB6660--2011, the thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine to evaluate thermal damage performance. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was room temperature circulating water. Thermal fatigue specimens were taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in [Figure number missing]. Figure 19 And as shown in Table 5. From Figure 19 As can be seen from Table 5, the thermal fatigue crack length of the wheel in Example 5 is significantly shorter than that of the wheel in Comparative Example 5 under different cycling temperatures.

[0097] Therefore, it can be seen that, under the premise of comparable impact performance and superior tensile properties, hardness, and fracture toughness compared to the comparative wheel, the wheel of Example 5 exhibits significantly improved wear resistance at room temperature and -40℃, and a significantly shorter thermal fatigue crack length. The optimized composition design, coupled with the heat treatment process of incremental flow quenching, results in superior overall mechanical properties and resistance to thermal damage for the wheel of Example 5.

[0098] Example 6

[0099] The molten steel with the chemical composition shown in Table 1 (Example 6) is processed through an electric arc furnace steelmaking process, an LF furnace refining process, an RH vacuum treatment process, a round billet continuous casting process, a hot rolling process for ingot cutting, a heat treatment process, a machining process, and a finished product inspection process. The heat treatment process is performed using the empirical formula: T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 In the formula, T is the quenching heating temperature, ℃; ω(V) is the V element content × 100, and the V content must be between 0.05-0.15%; this formula is only applicable when the precipitated V content accounts for about 20% of the total V content; T is determined to be 865℃. Considering the stability of on-site operation, the wheel is heated to 860-870℃ with the furnace and held for 2.8 hours. After being taken out of the furnace, a flow-increase quenching method (first stage quenching) is adopted. First, the nozzle pressure is kept constant at 0.10±0.02MPa, and 6 evenly distributed water spray panels are turned on for quenching at time t1. The nozzle system module is set to y1=17+0.05t1, t 1max = (1.5~1.8)×D, where y1 is the flow rate of a single nozzle, in meters. 3 / h; D is taken as 68mm for the rolled wheel rim thickness, and the time coefficient is taken as 1.8, t 1max =122.4s. The nozzle flow rate gradually increases because the wheel quenching method is tread surface water spray cooling. During cooling, the surface completes the microstructure transformation first. At this time, in order to ensure the microstructure transformation requirements of the shallow surface layer of the tread, an excessively high cooling rate is not required. The advantages of this are that, on the one hand, it can avoid the formation of excessively deep non-P microstructures in the tread and shallow surface layers, reducing subsequent machining allowances and benefiting the improvement of yield and cost reduction and efficiency; on the other hand, as the water spraying time increases, the microstructure transformation of the tread and shallow surface layers has been completed, while the cooling rate inside the rim is limited, so the flow rate increases with time. After 122.4s, constant flow quenching (second stage quenching) is adopted, and the water outlet panels of the three nozzles are closed at 120° intervals for constant water flow quenching. The nozzle pressure is kept constant at 0.08±0.02MPa. The nozzle system module is set as y2=25, t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle, m 3 / h; t2=2.5×D=170.0s. There is no pause between the first and second stages. Constant flow rate is used after the first stage because the microstructure of the tread and the area within 20mm below the tread has completed its transformation. Constant flow rate does not affect the area within 20mm below the tread and can radiate sufficient cooling capacity into the rim interior. At the same time, it can prevent heat from the spokes and the transition area between the spokes from being transferred into the rim interior and affecting the microstructure transformation. Finally, tempering treatment is carried out at 500±10℃ for 4.0 hours.

[0100] like Figure 6 , 12 As shown in Tables 15, 16 and 2, the metallographic structure of the wheel rim prepared in this embodiment is fine pearlite plus a small amount of ferrite, with no significant difference and comparable impact toughness. However, the tensile properties, cross-sectional hardness at 38.1 mm below the tread, and fracture toughness of the wheel in this embodiment are significantly higher than those of the wheel in Comparative Example 5, and the depth of abnormal structure is significantly smaller than that of the wheel in Comparative Example 6.

[0101] Comparative wear tests at room temperature and low temperature were conducted on a rolling contact fatigue test bench. The low-temperature rolling wear test involved adding a low-temperature environment system (connected to a refrigeration unit and a PID control system via a low-temperature chamber) to the test bench. The rolling wear test specimens were 40mm disc-shaped samples, all taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in Tables 3 and 4. As can be seen from Tables 3 and 4, the wear performance of the wheel of Example 6 at both room temperature and -40℃ is significantly better than that of the wheel of Comparative Example 6.

[0102] According to industry standard HB6660--2011, the thermal fatigue crack length of wheels made of different materials under 1000 thermal cycles at different temperature ranges was compared using a thermal fatigue testing machine to evaluate thermal damage performance. The test cycle temperatures were 400℃ and 650℃, with a heating time of 60s and a cooling time of 5s. The cooling medium was room temperature circulating water. Thermal fatigue specimens were taken from the same location on the wheel rims of the comparative example and this embodiment. The test results are shown in [Figure number missing]. Figure 19 And as shown in Table 5. From Figure 19 As can be seen from Table 5, the thermal fatigue crack length of the wheel in Example 6 is significantly shorter than that of the wheel in Comparative Example 6 under different cycling temperatures.

[0103] Therefore, it can be seen that, while the wheel of Example 6 exhibits superior tensile properties, hardness, impact properties, and fracture toughness compared to the comparative wheel, its wear resistance at room temperature and -40℃ is significantly improved, the Ac3 point temperature is significantly increased, the Ms point temperature is decreased, and the thermal fatigue crack length is significantly shorter. The optimized composition design, coupled with a flow-increasing quenching heat treatment process, results in superior overall mechanical properties and resistance to thermal damage for the wheel of Example 6.

[0104] Comparative Example 1:

[0105] The molten steel with the chemical composition shown in Table 1 (Comparative Example 1) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, ingot cutting and hot rolling, heat treatment, processing, and finished product inspection. Its wheel shape is completely consistent with that of Example 1. The quenching heating temperature is 850-870℃. After holding at a constant temperature for 3.0 hours, the product is removed from the furnace. The two-stage cooling process parameters are set according to Example 1. In the first stage, six evenly distributed water spray panels are activated for cooling. y = 17 + 0.05t1, t 1max The first stage of quenching was 124.5s, and the second stage was quenching with water pressure of 0.08±0.02MPa for 207.5s (t2=2.5×D). The tempering process was set according to Example 1.

[0106] Comparative Example 2:

[0107] The molten steel with the chemical composition shown in Table 1 (Comparative Example 2) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, hot rolling, heat treatment, machining, and finished product inspection. Its wheel shape was completely identical to that of Example 2. The quenching heating temperature was set to 865-875℃ as in Example 2, and after holding at that temperature for 2.8 hours, the steel was removed from the furnace and cooled with water at a pressure of 0.10 ± 0.02 MPa. Perform quenching for 300 seconds. The tempering process is set according to Example 2.

[0108] Comparative Example 3:

[0109] The molten steel with the chemical composition shown in Table 1 (Comparative Example 3) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, ingot hot rolling, heat treatment, machining, and finished product inspection. Its wheel shape is completely identical to that of Example 3. The quenching heating temperature was set to 880-890℃ as in Example 3, and after holding at that temperature for 2.7 hours, it was removed from the furnace and cooled. The first stage of cooling was carried out at a water pressure of 0.10±0.02MPa for 120 seconds. 1max Quenching of (1.5~1.8)×D) with a second-stage cooling pressure maintained at a constant water pressure of 0.08±0.02MPa. Perform 150s quenching. The tempering process was set according to Example 3.

[0110] Comparative Example 4:

[0111] The molten steel with the chemical composition shown in Table 1 (Comparative Example 4) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, ingot hot rolling, heat treatment, machining, and finished product inspection. Its wheel shape is completely identical to that of Example 4. The quenching heating temperature was set to 885-895℃ as in Example 4, and after holding at that temperature for 2.9 hours, it was removed from the furnace and cooled. The first stage of cooling was carried out under a water pressure of 0.10±0.02MPa. 70s quenching The second stage of cooling was set according to Example 4, with quenching at 0.08±0.02MPa for 165s, and the tempering process was set according to Example 4.

[0112] Comparative Example 5:

[0113] The molten steel with the chemical composition shown in Table 1 (Comparative Example 5) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, ingot hot rolling, heat treatment, machining, and finished product inspection to form the final product. Its wheel shape is completely identical to that of Example 5. The quenching heating temperature was set according to Example 5. 860-880℃ After holding at this temperature for 3.0 hours, remove from the oven and proceed with the process at a water pressure of 0.10±0.02MPa. 270s quenching The tempering process was set according to Example 5.

[0114] Comparative Example 6:

[0115] The molten steel with the chemical composition shown in Table 1 (Comparative Example 6) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, hot rolling, heat treatment, machining, and finished product inspection. Its wheel shape is completely identical to that of Example 6. The quenching heating temperature was set according to Example 6. 870-890℃ After holding at this temperature for 2.8 hours, the food is removed from the oven. The first stage of cooling is carried out at a water pressure of 0.10 ± 0.02 MPa. 30s quenchingThe second stage of cooling was set according to Example 6, with quenching at 0.08±0.02MPa for 170s, and the tempering process was set according to Example 6.

[0116] Comparative Example 7:

[0117] The molten steel with the chemical composition shown in Table 1 (Comparative Example 7) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, hot rolling, heat treatment, machining, and finished product inspection. The quenching heating temperature was determined according to the empirical formula T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 The temperature was set at 828℃, and the furnace was removed after holding the temperature for 2.8 hours. The furnace was then quenched for 290 seconds at a water pressure of 0.10±0.02MPa. The tempering process was set according to Example 1.

[0118] Comparative Example 8:

[0119] The molten steel with the chemical composition shown in Table 1 (Comparative Example 8) was processed through electric arc furnace steelmaking, LF furnace refining, RH vacuum treatment, round billet continuous casting, hot rolling, heat treatment, machining, and finished product inspection. The quenching heating temperature was determined according to the empirical formula T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 The target temperature was set at 835℃. After holding at 835℃ for 2.8 hours, the furnace was removed and subjected to two-stage cooling. In the first stage, the nozzle pressure was kept constant at 0.10±0.02MPa, and six evenly distributed water spray panels were activated for quenching at time t1. The nozzle system module was set with y1=17+0.05t1, t 1max =1.6×85=136.0s. After 136.0s, the water outlet panels of the three nozzles are closed at 120° intervals for the second stage of constant flow quenching. The nozzle pressure is 0.08±0.02MPa, and the flow rate of a single nozzle is 25m³ / s. 3 / h; t2=2.5×85=212.5s. The tempering process was set according to Example 2.

[0120] Table 2. Overall performance of wheels in the examples and comparative models.

[0121]

[0122]

[0123] Table 3. Wear performance of wheels at room temperature in examples and comparative cases.

[0124] Contact stress Tangential force / N Loop count Wear rate Example 1 1100 110 <![CDATA[10 6 ]]> 2.4 Example 2 1000 130 <![CDATA[10 6 ]]> 2.5 Example 3 1200 110 <![CDATA[10 6 ]]> 2.9 Example 4 1000 120 <![CDATA[10 6 ]]> 2.5 Example 5 1200 110 <![CDATA[10 6 ]]> 3.5 Example 6 1100 120 <![CDATA[10 6 ]]> 2.2 Comparative Example 1 1000 110 <![CDATA[10 6 ]]> 3.5 Comparative Example 2 900 130 <![CDATA[10 6 ]]> 2.7 Comparative Example 3 1100 100 <![CDATA[10 6 ]]> 3.6 Comparative Example 4 850 110 <![CDATA[10 6 ]]> 3.1 Comparative Example 5 1100 100 <![CDATA[10 6 ]]> 4.0 Comparative Example 6 1000 110 <![CDATA[10 6 ]]> 2.8 Comparative Example 7 980 110 <![CDATA[10 6 ]]> 3.6 Comparative Example 8 850 120 <![CDATA[10 6 ]]> 3.1

[0125] Table 4. Wear performance of wheels in the examples and comparative examples at -40℃

[0126]

[0127]

[0128] Table 5. Temperatures at Ac3 and Ms points and thermal damage properties of the examples and comparative examples.

[0129]

[0130]

[0131] The data underlined above do not meet the requirements of this invention.

[0132] The above detailed description of the present invention with reference to the embodiments and comparative examples is illustrative rather than limiting. Several embodiments can be listed according to the defined scope. Therefore, changes and modifications without departing from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A wheel, characterized in that, The wheels are made using heat-damage resistant heavy-duty wheel steel. The heat-damage resistant heavy-duty wheel steel comprises the following components by weight percentage: C 0.67-0.70%, Si 0.90-1.00%, Mn 0.80-0.90%, P ≤0.015%, S 0.006-0.015%, V 0.05-0.15%, Cr 0.20-0.30%, N 0.0050-0.0100%, with the remainder being Fe and unavoidable impurity elements; The method for producing the wheel includes a heat treatment process; the heat treatment process includes: quenching heating, flow-increment quenching, constant flow quenching, and tempering. The quenching heating temperature is T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 The quenching heating time is 2.5-3.0h; where T is the quenching heating temperature, °C; ω(V) is the V element content × 100; The incremental flow quenching process specifically involves placing the quenched and heated wheel, now homogenized with austenite, onto a quenching platform with six evenly distributed nozzle water outlet panels. All six nozzle water outlet panels, spaced 60° apart, are fully opened for quenching at time t1. The nozzle pressure is maintained constant at 0.10 ± 0.02 MPa. The nozzle system module is set to y1 = 17 + 0.05t1, where the maximum value of t1 is t 1max = (1.5-1.8)×D, where y1 is the flow rate of a single nozzle, m 3 / h; D is the rolled wheel rim thickness, mm; t1 is the quenching time, s; The constant flow quenching is performed by closing one nozzle outlet panel every 120° for constant flow quenching, maintaining a constant nozzle pressure of 0.08±0.02MPa. The nozzle system module is set with y2=25 and t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle (m³). 3 / h; D is the rolled wheel rim thickness, mm; t2 is the quenching time, s; The tempering process is performed at 500±10℃ for 4.0±0.5 hours.

2. The wheel according to claim 1, characterized in that, The tensile properties of the wheel are: tensile strength Rm≥1190MPa, elongation A 50 ≥15%; Hardness at 38.1mm below the tread surface ≥330HB, room temperature impact performance U5≥11J, -60℃ impact performance U 5,2 ≥40J, fracture toughness ≥48.6MPa·m 1 / 2 The depth of the abnormal tissue on the wheel is ≤3.0mm.

3. The wheel according to claim 1 or 2, characterized in that, The composition of the heat-damage resistant heavy-duty wheel steel satisfies: 425 < A value < 445, where A value = 930 - [570 × %C] - [80 × %Mn] - [20 × %Si] - [50 × %Cr] - [20 × %V].

4. A method for producing a wheel according to any one of claims 1-3, characterized in that, The production method includes a heat treatment process; the heat treatment process includes: quenching heating, flow-increment quenching, constant flow quenching, and tempering. The quenching heating temperature is T = 820 + 791.7 × ω(V) - 2083.3 × ω(V). 2 The quenching heating time is 2.5-3.0h; where T is the quenching heating temperature, °C; ω(V) is the V element content × 100; The incremental flow quenching process specifically involves placing the quenched and heated wheel, now homogenized with austenite, onto a quenching platform with six evenly distributed nozzle water outlet panels. All six nozzle water outlet panels, spaced 60° apart, are fully opened for quenching at time t1. The nozzle pressure is maintained constant at 0.10 ± 0.02 MPa. The nozzle system module is set to y1 = 17 + 0.05t1, where the maximum value of t1 is t 1max = (1.5-1.8)×D, where y1 is the flow rate of a single nozzle, m 3 / h; D is the rolled wheel rim thickness, mm; t1 is the quenching time, s; The constant flow quenching is performed by closing one nozzle outlet panel every 120° for constant flow quenching, maintaining a constant nozzle pressure of 0.08±0.02MPa. The nozzle system module is set with y2=25 and t2=(2.5-3)×D, where y2 is the flow rate of a single nozzle (m³). 3 / h; D is the rolled wheel rim thickness, mm; t2 is the quenching time, s; The tempering process is performed at 500±10℃ for 4.0±0.5 hours.

5. The production method according to claim 4, characterized in that, After the incremental flow quenching is completed, constant flow quenching is performed directly.

6. An application of the wheel according to any one of claims 1-3, characterized in that, The wheels are used in the manufacture of heavy-haul railway freight cars with an axle load of 30t or more and an operating speed of 120km / h or less.

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