Steel for passenger locomotive wheels in high-cold areas and production method, wheel and production method

Abstract

The present invention provides a steel for passenger locomotive wheels suitable for use in high-cold areas, a production method, a wheel and a production method, the composition of which is as follows: C: 0.44-0.54%, Si: 0.40-0.65%, Mn: 0.80-1.2%, Cr: 0.15-0.30%, V: 0.08-0.15%, Al: 0.008-0.015%, P: 0.005-0.010%, S: 0.006-0.015%; TO: ≤10ppm, [H]: ≤1.5ppm, [N]: 50-80ppm, and the rest is Fe and unavoidable impurity elements. By designing a matching production process and heat treatment method, the produced wheel has more excellent rolling contact fatigue resistance and wear resistance, thereby reducing the phenomenon of anti-peeling and falling off, and further improving the service stability of the wheel throughout its life cycle.

Description

Technical Field

[0001] The invention belongs to the technical field of railway wheels, and specifically relates to steel for passenger locomotive wheels in high-cold areas and a production method, a wheel and a production method. Background Art

[0002] The locomotive wheel plays the role of transmitting traction power. It is one of the key parts of the locomotive and is also an important component with the most stringent service conditions and is related to the safety of train operation. my country has a vast territory, a deep inland area, and great differences in climate and environment between regions. Under heavy load and speed increase conditions, locomotives have long routes, high-density operation, low temperature, environmental corrosion, wind and sand damage, etc. These are all unique operating conditions in my country, which makes the service of locomotive wheels more demanding and their failure problems more prominent.

[0003] During the use of locomotive wheels, there will be damages such as tread cracks, peeling, abrasions, edge rolling, rim cracks (internal cracks), etc. At present, the TB / T 3154-2007 "Locomotive and Rolling Stock Wheel and Wheel Rim Damage Code" standard has systematically and comprehensively summarized the location, type and cause of these damages. Among these damages, the most common is wheel tread damage. With the rapid development of railway passenger and freight transportation, Harmony locomotives have been put into service on a large scale. Compared with other railway vehicles, locomotives have the characteristics of large traction and traction speed, which makes the contact stress on their wheel treads high and the mechanical-thermal load is large, which causes the wheel tread peeling problem to occur from time to time. The frequent peeling problem of locomotive wheels not only disrupts the normal operation order of the railway, but also greatly increases the frequency of locomotive wheel turning and maintenance, reduces the service life of the wheels, and increases the railway operation cost.

[0004] In the prior art, the patent with publication number CN107904501A and publication date April 13, 2018, discloses a high-strength thin-gauge wheel with good fatigue resistance and a production method, and its chemical composition and weight percentage content are: C: 0.05-0.07%, Si: 0.15-0.30%, Mn: 1.40-1.60%, P≤0.008%, S≤0.002%, Als: 0.020-0.060%, Nb: 0.046-0.055%, and the balance is Fe and unavoidable impurities. Its strength is low and cannot meet the use requirements of high-cold areas. Summary of the invention

[0005] The purpose of the present invention is to provide a steel and a production method suitable for passenger locomotive wheels in high-cold areas. Through component design and coordinated production methods, the produced steel has aluminum oxide inclusions ≤3μm, total oxygen stability in the steel ≤10ppm, the ingot structure is a uniformly grown columnar crystal structure, the austenite grain size of the steel is above grade 10.0, and the comprehensive performance is excellent, so the steel can be used for the production of passenger locomotive wheels in high-cold areas.

[0006] The wheel and production method provided by the present invention are produced using the above-mentioned steel suitable for passenger locomotive wheels in high-cold areas. The structure of the steel after heat treatment is fine ferrite + pearlite. Compared with traditional locomotive wheels, it has more excellent rolling contact fatigue resistance and wear resistance, thereby reducing peeling and shedding phenomena, further improving the service stability of the wheel throughout its life cycle, and at the same time having a ductile-brittle transition temperature below -60°C.

[0007] The specific technical solutions of the present invention are as follows:

[0008] The steel for passenger locomotive wheels in high-cold areas provided by the present invention comprises the following components in percentage by mass:

[0009] C: 0.44-0.54%, Si: 0.40-0.65%, Mn: 0.80-1.2%, Cr: 0.15-0.30%, V: 0.08-0.15%, Al: 0.008-0.015%, P: 0.005-0.010%, S: 0.006-0.015%; TO: ≤10ppm, [H]: ≤1.5ppm, [N]: 50-80ppm, the rest are Fe and unavoidable impurity elements.

[0010] The composition of the steel for passenger locomotive wheels in high-cold areas also meets the following requirements:

[0011] Fn1=20.3×C+4.9×Si+8.9×Mn+6.8×Cr+50.1×V, 25≤Fn1≤32;

[0012] Fn2=(2.08×Al+3.11×V) / (26.7×[N]), 1.5≤Fn2≤3;

[0013] When calculating using the above formula, substitute the mass percentage of each element × 100% into the formula.

[0014] The present invention provides a production method for passenger locomotive wheel steel suitable for use in high-cold areas, comprising the following process flow: electric arc furnace smelting-LF refining-RH vacuum treatment-continuous casting-slow cooling.

[0015] The electric arc furnace smelting: during the electric furnace blowing process, oxygen, nitrogen and argon mixed gas are blown by an oxygen lance from the late melting period, and slag-making materials are added in time to reduce the decarburization reaction rate during the dephosphorization process under the condition of effectively ensuring the thermodynamics and kinetics of dephosphorization, so that the carbon content in the electric furnace terminal steel is higher, the phosphorus content of slag-free steel is P≤0.08%, the steel tapping temperature is ≥1600°C, and Si-iron (silicon diffusion primary deoxidation) and carbon powder are used for steel tapping to avoid the generation of Al2O3 inclusions.

[0016] The LF refining comprises: reducing the ladle top slag with calcium carbide and SiC (deoxidation by diffusion of silicon and carbon in the process); controlling the [Ca] and [Als] contents in the steel as low as possible while taking into account the desulfurization capacity of the LF slag basicity, and avoiding the generation of Al2O3 or calcium aluminate inclusions as much as possible; controlling the active oxygen in the molten steel to 20-30ppm at the end of refining, further reducing the active oxygen in the steel by utilizing the vacuum carbon deoxidation principle in the RH process, controlling the active oxygen in the steel to 9-11ppm before adding aluminum for final deoxidation in the late RH period, adding aluminum for final deoxidation before the RH end point, deoxidation TO≤6ppm, temperature: 1590-1650°C, generating fine dispersed Al2O3 micro inclusions.

[0017] The RH vacuum treatment: RH vacuum cycle degassing to set H≤1.0ppm, accurately control N: 50-80ppm.

[0018] The continuous casting: the continuous casting process design appropriately increases the superheat of the molten steel in the tundish and the primary cooling rate of the strong cooling process of the ingot, the superheat of the molten steel in the tundish is 30-45°C; the primary cooling rate of the strong cooling process of the ingot is 3000-5500 l / min, the secondary cooling specific water volume is 0.15-0.25 L / kg, and the casting and drawing speed is 0.25-0.60 m / min, so that dense columnar crystals are formed at the ingot portion corresponding to the rim, the organizational density is improved, and the fine MnS precipitated at the solidification end of the secondary dendrite is promoted to be distributed in a uniform and dispersed form, thereby improving the uniformity and dispersibility of the MnS inclusion distribution in the ingot and reducing the size of the MnS inclusion.

[0019] The slow cooling is performed at a temperature of ≥600°C and a slow cooling time of ≥48h.

[0020] In the microstructure of the steel produced for passenger locomotive wheels in high-cold areas, MnS inclusions account for 80-87%, MnS-wrapped Al2O3 inclusions account for 10-17%, and the remainder is oxide inclusions; oxide inclusions above 10μm account for 0.6%-1%; the average size of MnS inclusions is 2.8-3.2μm, and 98% of the MnS inclusions are less than 7μm in size; the average size of alumina inclusions is ≤3μm; 97% of the alumina inclusions are less than 7μm in size; the total oxygen stability in the steel is ≤10ppm, the ingot microstructure is a uniformly grown columnar crystal structure, and the austenite grain size of the steel is above grade 10.0.

[0021] The present invention controls the type and size of inclusions from the source, thereby ultimately achieving two purposes: 1) improving the purity of wheel steel, reducing the size of brittle oxide inclusions, precipitating soft-phase manganese sulfide on the surface of fine Al2O3 during the solidification process, wrapping the Al2O3 brittle inclusions, and reducing the source of crack generation; 2) forming a large number of fine manganese sulfide inclusions in the wheel, utilizing the crack-stopping effect of the tiny pores of manganese sulfide to prevent crack propagation, thereby improving the fracture toughness of the wheel and improving the safety of wheel operation.

[0022] The wheel production method provided by the present invention specifically comprises: sawing, heating, rolling, slow cooling, heat treatment and processing the above steel for passenger locomotive wheels suitable for high-cold areas to obtain the wheel;

[0023] The heating process includes: controlling the temperature of the steel billet in the heating section of the heating furnace to 1290-1310° C., controlling the soaking temperature to 1250-1290° C., and controlling the total time of preheating, heating and soaking to 4h-5h.

[0024] The rolling process includes: a starting rolling temperature of 1100-1150°C and a final rolling temperature of ≥870°C;

[0025] The slow cooling: after rolling, it is slow cooled in a pit at a temperature not lower than 500°C, and the slow cooling time is ≥ 6h.

[0026] The heat treatment is as follows: first heating and heat preservation, then weak cooling and then strong cooling, and finally tempering.

[0027] During the heat treatment, the heating and heat preservation are as follows: the temperature of the heating section is 880-910°C, the temperature of the soaking section is 840-880°C, and the total heating time is 2.5-3.0h, of which the soaking section time is 0.5-1.0h.

[0028] The weak cooling specifically includes: using water cooling to make the metal near the surface of the rim tread cool at a rate of 0.2°C / s-0.4°C / s; weak cooling to ensure that 8-10mm of the wheel tread is hardened through.

[0029] The strong cooling specifically includes: using water cooling, with a rim cooling rate of 6-10°C / s; strong cooling to ensure that the entire rim of the wheel is hardened, and does not affect the wheel spoke plate, ensuring that the spoke plate is in a normalized state.

[0030] The tempering is specifically: tempering treatment at 460-520° C. for 3-5 hours.

[0031] In the specific heat treatment of the present invention, the heating section in the heat treatment furnace is first heated at 880-910°C, and the soaking section is heated at 840-880°C. The total heating time is 2.5-3.0 hours, of which the soaking section time is 0.5-1.0 hours, to ensure that the internal structure of the wheel is uniformly austenitized. According to the phase change characteristics of the wheel steel, weaker water cooling is first used to make the metal near the surface of the rim tread cool at a rate of 0.2°C / s-0.4°C / s, while ensuring that the internal temperature of the rim is at the Ac3 point (about 560°C or above), so that the FP transformation occurs first within a certain depth near the surface of the wheel tread, and the inside of the rim is still austenite. After the weak spraying is completed, the strong spraying nozzle starts to spray the wheel tread. The cooling rate of the rim is 6-10℃ / s. The metal inside the rim quickly passes through the Ar3~Ar1 temperature range, which inhibits the precipitation of proeutectoid ferrite and prevents the internal structure from transforming to bainite. Finally, it is tempered at 460-520℃ for 3-5 hours.

[0032] The wheel provided by the present invention is produced by adopting the above-mentioned heat treatment method.

[0033] The wheel rim performance: rim tensile strength Rm 1000-1080MPa, yield strength ≥760MPa, yield strength ratio 0.74-0.76, elongation A 50 ≥28%, section shrinkage Z≥48%; rim impact performance: -60℃ longitudinal impact value KU (notch depth 2mm, radius 5mm arc) ≥100J / cm 2 , -20℃ impact energy KV2≥14J, 20℃ impact energy KU5≥29J; spoke impact performance: 20℃ impact energy KU2≥20J, -40℃ impact energy KU2≥13J; rim wear limit Brinell hardness ≥300HBW; wheel fracture toughness at -60℃ ≥60MPa . m 1 / 2 , Wheel fracture toughness ≥70MPa at -40℃ . m 1 / 2 , Wheel fracture toughness ≥80MPa at 20℃ . m 1 / 2 The wheel structure is ferrite and pearlite, and the pearlite lamellar spacing is 0.100-0.150 μm; the grain size 30 mm below the tread is finer than grade 9.

[0034] The design ideas of the present invention are as follows:

[0035] C: C is necessary for steel to obtain high strength and hardness. The C content in traditional wheel steel is relatively high. Although high C content is beneficial to the strength and hardness of steel, it is extremely detrimental to the plasticity and toughness of steel, and reduces the yield strength ratio, increases the decarburization sensitivity, and deteriorates the fatigue resistance and processing performance of steel. Therefore, the C content in steel should be appropriately reduced to improve the plasticity and toughness of steel, but too low C content will affect the strength of steel. Combined with the requirements of DI value and the addition of other elements, it is controlled at 0.44-0.54%.

[0036] Si: Si is the main deoxidizing element in steel, and has a strong solid solution strengthening effect. It can also improve the hardenability of wheel steel. However, too high Si content will reduce the plasticity and toughness of steel, increase the activity of C, promote the decarburization and graphitization tendency of steel during rolling and heat treatment, and make smelting difficult and easy to form inclusions, which deteriorates the fatigue resistance of steel. Therefore, the Si content is controlled to 0.40-0.65%.

[0037] Mn: Mn is an element that improves the quenching characteristics without inhibiting low temperature toughness, and it is preferred to add 0.8% or more of Mn. In addition, Mn can act synergistically with Si, and part of the dissolved oxygen captured by Mn and Si can distribute the dissolved oxygen between elements other than Al, thereby limiting the risk of forming large clustered alumina inclusions. However, when added in an amount greater than 1.2%, the center segregation that occurs not only reduces the low temperature toughness but also improves the hardenability of the steel. Since Mn center segregation is a factor that causes hydrogen cracking, it is preferred to limit the content to 0.8% to 1.2%.

[0038] S: Sulfur easily forms MnS inclusions with manganese in steel, making the steel hot brittle. However, adding a small amount of S will significantly improve the cutting performance of wheel steel without affecting product performance, and MnS also has the effect of refining grains. The uniform and dispersed precipitation of MnS during the solidification process requires appropriate [S] in the steel. The standards of wheel customers have strict requirements on the rating of MnS inclusions. Therefore, the needs of both aspects should be comprehensively considered in the process design. Through comparison and analysis of previous data, it is determined that the optimal value of molten steel [S] in the inclusion plasticization process is controlled at 0.006-0.015%.

[0039] P: It is an element with a strong tendency to segregate, which increases the cold brittleness of steel, reduces plasticity, and is harmful to the uniformity of product structure and performance. Control P ≤ 0.010%. However, if you want to reduce the P content too much, the refining cost will increase excessively. Therefore, considering the usual industrial production, the preferred lower limit of the P content is 0.005%.

[0040] Cr: Cr can improve the hardenability and strength of steel. Cr can also reduce the activity of C, reduce the decarburization tendency of steel surface during heating, rolling and heat treatment, and obtain high fatigue resistance. Therefore, the Cr content cannot be less than 0.15%. Too high Cr will reduce the toughness of steel, and a large amount of carbides will appear in the carburized layer structure, affecting the performance of the carburized layer. Therefore, the Cr content cannot be higher than 0.30%. The Cr content is controlled at 0.15-0.30%.

[0041] Al: Al is an effective deoxidizer and can form AlN to refine grains. When the Al content is lower than 0.008%, the effect is not obvious. When it is higher than 0.015%, it is easy to form coarse inclusions, which deteriorates the performance of steel. Therefore, the Al content should be controlled at 0.008-0.015%.

[0042] V: Vanadium is an important strong carbonitride forming element in wheel steel. Through heating dissolution and cooling precipitation, interstitial VC, V4C3 and nitrogen-rich V(C,N) second phase particles can be formed in the steel, resulting in strong precipitation strengthening and fine grain strengthening, which plays a role in significantly improving the yield strength. In addition, the formation of vanadium-containing second phase particles, the micro-regions around the particles are carbon-poor and have a smaller lattice mismatch with ferrite, which promotes the formation of proeutectoid ferrite and plays a role in moderately increasing the wear rate, thereby achieving the purpose of coordinating the competitive relationship between contact fatigue and wear and improving the surface contact fatigue resistance of the wheel. The present invention sets the vanadium content range to 0.08% to 0.15%, because, on the one hand, if the vanadium content exceeds this value, a higher heating temperature must be used to produce a significant strengthening effect, otherwise, due to the dual factors of low solid solution V content and low matrix carbon content, the effect of V microalloying on improving strength will be greatly limited, and even a negative effect will be produced; on the other hand, if the vanadium content is too low, it will not play a significant precipitation strengthening role, and even due to improper heat treatment system, vanadium will cause a decrease in strength due to carbon in the matrix.

[0043] [N]: N forms nitrides with Al, V, etc. to inhibit austenite grain growth and help improve toughness and strength. However, when the content is excessive and greater than 0.05%, N exists in a solid solution state, and N in a solid solution state has an adverse effect on low temperature toughness. Therefore, the [N] content should be controlled at 50-80ppm.

[0044] TO and [H]: TO forms oxide inclusions in steel, so control TO≤10ppm; [H] forms white spots in steel, which seriously affects product performance, so control [H]≤1.5ppm.

[0045] According to the strengthening role of each element in the wheel steel, the coefficient matching is fitted according to the different strengthening effects of each element to obtain the Fn1 formula. When Fn1 is less than 25, the wear resistance and rolling fatigue resistance are almost not improved compared with the case where the "CL60" railway wheel steel of TB / T2817 is used as the raw material, and sometimes it is reduced compared with "CL60". Therefore, it is difficult to use as a raw material for railway wheels used in extremely harsh environments such as increased driving distance and increased loading load. On the other hand, if Fn1 exceeds 32, it is difficult to obtain the pearlite main body structure and the wear resistance is reduced, and the hardness is too high, so the toughness is reduced. If Fn1 is between 25-32, the rolling fatigue life is increased by more than 50% compared with the case where the "CL60" railway wheel steel is used as the raw material.

[0046] The present invention determines 1.5≤Fn2≤3 based on the ratio of Al, V and N and the influence on toughness; when Fn2 is less than 1.5, the wheel toughness index is significantly reduced, and when Fn2 is greater than 3, the wheel toughness index is reduced, and the strength and hardness index will also decrease.

[0047] The present invention conducts research on the optimization of locomotive wheel materials through the microalloying technology route, which has positive significance in promoting the development of the key wheel component industry and ensuring the efficient operation of locomotives.

[0048] Compared with the prior art, the wheel steel prepared by the present invention has aluminum oxide inclusions ≤3μm, total oxygen stability in the steel ≤10ppm, the ingot structure is a uniformly grown columnar crystal structure, and the austenite grain size of the steel is above 10.0 grade. The wheel fracture toughness prepared by the above wheel steel is ≥80MPa . m 1 / 2 , -60℃ longitudinal impact value KU (notch depth 2mm, radius 5mm arc) ≥100J / cm 2 The rim tensile strength (Rm) is 1000-1080MPa, the yield strength is ≥760MPa, the rim wear limit Brinell hardness is ≥300HBW, the contact fatigue resistance and wear resistance are all high, and the strength, hardness and toughness are well matched. The grain size is finer than grade 9, thereby obtaining better comprehensive mechanical properties. At the same time, the wear resistance and contact fatigue resistance of the wheel are good. According to the present invention, the structure of the steel after heat treatment is fine ferrite-pearlite. Compared with traditional locomotive wheels, it has more excellent rolling contact fatigue resistance and wear resistance, thereby reducing the phenomenon of anti-peeling and falling off, further improving the service stability of the wheel throughout its life cycle, and having a tough-to-brittle transition temperature below -60°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The structure of the wheel rim of Example 1 is fine ferrite and a small amount of ferrite;

[0050] Figure 2 The microstructure of the wheel rim of Comparative Example 1 is fine pearlite and a small amount of ferrite + a small amount of bainite;

[0051] Figure 3 This is a diagram of the wheel rim inclusion package of Example 1;

[0052] Figure 4 This is a diagram of the wheel rim inclusion package of Comparative Example 1. DETAILED DESCRIPTION

[0053] Example 1-Example 3

[0054] The steel for passenger locomotive wheels suitable for use in high-cold areas includes the following mass percentage components: as shown in Table 1, and the remainder not shown in Table 1 is Fe and unavoidable impurities.

[0055] Comparative Example 1-Comparative Example 5

[0056] Wheel steel includes the following components in mass percentage: as shown in Table 1, and the balance not shown in Table 1 is Fe and inevitable impurities.

[0057] Table 1 Chemical compositions of smelting of various embodiments and comparative examples

[0058]

[0059] The ingredients of Comparative Example 4 and Example 1 are the same, and the ingredients of Comparative Example 5 and Example 3 are the same.

[0060] The above embodiments and comparative examples are applicable to the production method of steel for passenger locomotive wheels in high-cold areas, including the following process flow: electric arc furnace smelting-LF refining-RH vacuum treatment-continuous casting-slow cooling; the process control is as follows:

[0061] In the electric arc furnace smelting process, oxygen, nitrogen and argon mixed gas are blown by an oxygen lance from the late melting period for blowing, and slag-making materials are added in time to reduce the decarburization reaction rate in the dephosphorization process under the condition of effectively ensuring the thermodynamics and kinetics of dephosphorization, so that the carbon content in the electric furnace terminal steel is higher, the phosphorus content P is less than or equal to 0.08% in slag-free steelmaking, the steelmaking temperature is greater than or equal to 1600°C, and Si-iron (silicon diffusion primary deoxidation) and carbon powder are used for steelmaking to avoid the generation of Al2O3 inclusions.

[0062] The LF refining comprises: calcium carbide and SiC are used to reduce the ladle top slag in the LF furnace (the silicon and carbon are diffused and deoxidized in the process); the basicity of the LF slag takes into account the desulfurization capacity while controlling the [Ca] and [Als] contents in the steel as low as possible to avoid the generation of Al2O3 or calcium aluminate inclusions as much as possible; the active oxygen in the molten steel can be controlled to 20-30ppm at the refining end point, the vacuum carbon deoxidation principle is used in the RH process to further reduce the active oxygen in the steel, the active oxygen in the steel can be controlled to 9-11ppm before the final deoxidation by adding aluminum in the late RH period, and the final deoxidation by adding aluminum before the RH end point, the deoxidation TO≤6ppm, the temperature is 1590-1650°C, and fine and dispersed Al2O3 fine inclusions are generated.

[0063] The RH vacuum treatment: RH vacuum cycle degassing to set H≤1.0ppm, accurately control N: 50-80ppm.

[0064] The continuous casting: the continuous casting process design appropriately increases the superheat of the molten steel in the tundish and the primary cooling rate of the strong cooling process of the ingot, the superheat of the molten steel in the tundish is 30-45°C; the primary cooling rate of the strong cooling process of the ingot is 3000-5500 l / min, the secondary cooling specific water volume is 0.15-0.25 L / kg, and the casting and drawing speed is 0.25-0.60 m / min, so that dense columnar crystals are formed at the ingot portion corresponding to the rim, the organizational density is improved, and the fine MnS precipitated at the solidification end of the secondary dendrite is promoted to be distributed in a uniform and dispersed form, thereby improving the uniformity and dispersibility of the MnS inclusion distribution in the ingot and reducing the size of the MnS inclusion.

[0065] The slow cooling: the slow cooling temperature of the ingot is ≥600°C, and the slow cooling time is ≥48h.

[0066] The parameters of electric arc furnace smelting, LF refining, RH vacuum treatment, continuous casting and slow cooling in the above embodiments and comparative examples are applicable to the production method of steel for passenger locomotive wheels in high-cold areas as shown in Table 2.

[0067] Table 2 Main production process parameters of each embodiment and comparative example

[0068]

[0069] The results of the steel grain and inclusion detection of the above embodiments and comparative examples are shown in Table 3.

[0070] Table 3 Product inspection of the embodiments of the present invention and the comparative examples

[0071]

[0072] The steel for passenger locomotive wheels in high-cold areas produced in the above embodiments and comparative examples is used to produce wheels, which includes the following process flow: sawing - heating - rolling - slow cooling - heat treatment - processing.

[0073] The heating process includes: controlling the temperature of the steel billet in the heating section of the heating furnace between 1290° C. and 1310° C., controlling the soaking temperature between 1250° C. and 1290° C., and controlling the total time of preheating, heating and soaking to 4 h and 5 h.

[0074] The rolling process: the starting rolling temperature is 1100-1150℃, the final rolling temperature is ≥870℃

[0075] The slow cooling: after rolling, it is slow cooled in a pit at a temperature not lower than 500°C, and the slow cooling time is ≥ 6h.

[0076] The heat treatment is as follows: heating at 880-910°C in the heating section of the heat treatment furnace, 840-880°C in the soaking section, and a total heating time of 2.5-3.0h, of which the soaking section time is 0.5-1.0h, to ensure that the internal structure of the wheel is uniformly austenitized. According to the phase change characteristics of the wheel steel, a weaker water cooling is first used to make the metal near the surface of the rim tread cool at a rate of 0.2°C / s-0.4°C / s, while ensuring that the internal temperature of the rim is at the Ac3 point (about 560°C or above), so that the FP transformation occurs first within a certain depth near the surface of the wheel tread, and the inside of the rim is still austenite. After the weak spraying is completed, the strong spray nozzle begins to spray the wheel tread, the rim cooling rate is 6-10°C / s, and the metal inside the rim quickly passes through the Ar3~Ar1 temperature range, which inhibits the precipitation of proeutectoid ferrite and prevents the internal structure from transforming to bainite, and finally tempering treatment is performed at 460-520°C for 3-5 hours.

[0077] The main process parameters for producing wheels in the above embodiments and comparative examples are shown in Table 4 and Table 5.

[0078] Table 4 Wheel rolling process parameters for each embodiment and comparative example

[0079]

[0080] Table 5 Heat treatment process parameters of wheels produced in various embodiments and comparative examples

[0081]

[0082] The performance of the wheels produced in the above embodiments and comparative examples is shown in Table 6.

[0083] Table 6 Performance of wheels manufactured in Examples 1-3 and Comparative Examples 1-5

[0084]

[0085]

[0086] Table 6: Performance of wheels manufactured in Examples 1-3 and Comparative Examples 1-3

[0087]

[0088] Cyclic plasticity test of ratchet behavior of wheel materials in the above embodiments and comparative examples:

[0089] A rod-shaped specimen was sampled 15 mm below the tread and an axial cyclic tension-compression fatigue test with three stress amplitudes was carried out under constant average stress. The loading waveform was a sine wave with a frequency of 0.1 Hz. The test was stopped when the specimen broke. The test stress loading condition parameters are shown in Table 7, and the test results are shown in Table 8.

[0090] Table 7 Stress loading conditions

[0091]

[0092] Table 8 Ratchet life of each embodiment and comparative example / cycle

[0093] Loading conditions / MPa 100±750 100±700 100±650 Example 1 204 607 1187 Example 2 198 587 1176 Example 3 196 585 1172 Comparative Example 1 28 46 103 Comparative Example 2 19 41 88 Comparative Example 3 12 34 67 Comparative Example 4 68 57 117 Comparative Example 5 39 41 89

[0094] The wear performance and contact fatigue performance comparison tests were carried out on the MMS-2A microcomputer controlled testing machine in accordance with GB 10622 "Metallic Material Rolling Contact Fatigue Test Method" standard, and the test results are shown in Tables 9 and 10 respectively. During the test, the main sample is the wheel sample prepared in each embodiment or comparative example of the present invention, and the auxiliary sample is the U71Mn rail sample with the same hardness, and the diameter of the main sample and the auxiliary sample is 60mm. Wear test: a group of 3 sets of samples, the main sample speed is 360rpm, the auxiliary sample speed is 400rpm, the corresponding rotation slip rate is 0.75%, the contact stress is 1100MPa, and the number of cycles is 500,000 times. Contact fatigue test: a group of 6 sets of samples, the speed is 2000rpm, the corresponding rotation slip rate is 0.3%, the contact stress is 1100-1500MPa, and 20# engine oil is used for lubrication.

[0095] Table 9 Comparison of wheel wear performance of Examples 1-3 and Comparative Examples 1-5

[0096]

[0097]

[0098] Table 10 Comparison of wheel contact fatigue performance between Examples 1-3 and Comparative Examples 1-5

[0099]

[0100] The underlined data above are data that do not meet the requirements of the present invention.

[0101] The wheel produced by the present invention has more excellent rolling contact fatigue resistance and wear resistance, thereby reducing the peeling and falling off phenomena, further improving the service stability of the wheel throughout its life cycle, and at the same time has a ductile-brittle transition temperature below -60°C.

Claims

1. A method for producing a wheel, characterized in that: The production of wheels using steel suitable for passenger locomotive wheels in high-cold regions includes heating, rolling, slow cooling and heat treatment; The steel for passenger locomotive wheels in high-cold areas includes the following components in percentage by mass: C: 0.44-0.54%, Si: 0.40-0.65%, Mn: 0.80-1.2%, Cr: 0.15-0.30%, V: 0.08-0.15%, Al: 0.008-0.015%, P: 0.005-0.010%, S: 0.006-0.015%; TO: ≤10ppm, [H]: ≤1.5ppm, [N]: 50-80ppm, the rest are Fe and unavoidable impurity elements; the composition of the steel for passenger locomotive wheels in high-cold areas meets the following requirements: Fn1=20.3×C+4.9×Si+8.9×Mn+6.8×Cr+50.1×V, 25≤Fn1≤32; Fn2=(2.08×Al+3.11×V) / (26.7×[N]), 1.5≤Fn2≤3; In the structure of the steel suitable for passenger locomotive wheels in high-cold areas, MnS inclusions account for 80-87%, MnS-wrapped Al2O3 inclusions account for 10-17%, and the remainder is oxide inclusions; oxide inclusions larger than 10 μm account for 0.6%-1%; the average size of MnS inclusions is 2.8-3.2 μm, and 98% of the MnS inclusions are less than 7 μm; the average size of alumina inclusions is ≤3 μm; 97% of the alumina inclusions are less than 7 μm in size; The total oxygen in the steel is stable ≤10ppm, the ingot structure is a uniformly grown columnar crystal structure, and the austenite grain size of the steel is above 10.0 grade; The heating is as follows: the temperature of the steel billet in the heating section of the heating furnace is controlled between 1290-1310° C., the soaking temperature is controlled between 1250-1290° C., and the total time of preheating, heating and soaking is controlled between 4h and 5h; The rolling process includes: a starting rolling temperature of 1100-1150°C and a final rolling temperature of ≥870°C; The heat treatment is as follows: firstly heating and heat preservation: the temperature of the heating section is 880-910°C, the temperature of the soaking section is 840-880°C, the total heating time is 2.5-3.0h, of which the soaking section time is 0.5-1.0h; then weak cooling is first performed, so that the metal near the surface of the rim tread is cooled at a rate of 0.2°C / s-0.4°C / s, then strong cooling is performed, and the cooling rate of the rim is 6-10°C / s, and finally tempering is performed.

2. The production method according to claim 1, characterized in that The production method of the steel for passenger locomotive wheels in high-cold areas includes the following process flow: electric arc furnace smelting-LF refining-RH vacuum treatment-continuous casting-slow cooling.

3. The production method according to claim 2, characterized in that: In the electric arc furnace smelting, the phosphorus content of slag-free steel is P≤0.08%, and the steel tapping temperature is ≥1600°C; The LF refining: deoxidation TO≤6ppm, temperature: 1590-1650℃; The RH vacuum treatment: RH vacuum cycle degassing to set H≤1.0ppm, accurately control N: 50-80ppm.

4. The production method according to claim 2, characterized in that: The continuous casting: the superheat degree of molten steel in the tundish is 30-45°C; the primary cooling speed of the strong cooling process of the casting billet is 3000-5500l / min, the secondary cooling water volume is 0.15-0.25L / kg, and the casting and drawing speed is 0.25-0.60m / min.

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