Low-cost 510mpa grade hot-rolled wheel steel and method of making same

Abstract

The application discloses a low-cost 510MPa-grade hot-rolled wheel steel and a preparation method thereof, and belongs to the field of materials and metallurgy technology, and comprises the following components in percentage by weight: C: 0.08% to 0.13%, Si: 0.1% to 0.15%, Mn: 0.95% to 1.20%, P: 0.020% or less, S: 0.015% or less, Al: 0.022% to 0.033%, N: 0.0037% to 0.0055%, and the balance of Fe and inevitable impurities, and 0.27 <= (C+Mn / 6) <= 0.32. The low-cost 510MPa-grade wheel steel plate with a thickness of 4 to 10 mm is produced, the steel plate has excellent low-temperature toughness and other characteristics, the problems of high alloy cost and the like are solved, and the low-cost, high strength and toughness can guarantee the service safety of the wheel steel plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of materials and metallurgy, and more particularly to a low-cost 510MPa-grade hot-rolled wheel steel and a preparation method thereof. BACKGROUND

[0002] A wheel is an important safety structure in automobile driving, and a steel wheel assembly is obtained through a series of strict manufacturing processes such as rolling or spinning forming, welding, paint spraying treatment, and has the advantages of high precision, light weight, long fatigue life, and reliable safety. The hot-rolled raw material steel plate for manufacturing a wheel requires high strength, toughness and plasticity, high fatigue resistance, impact resistance, and high surface quality. At present, the use of 600MPa or above high-strength wheel steel is less in the market, and the use of hot-rolled steel plate with a tensile strength of less than 600MPa is still the mainstream material for manufacturing automobile wheels in the market. The steel plate with a tensile strength of 510MPa, which accounts for a large proportion at present, generally adopts a low-carbon and low-manganese composition system. In order to ensure that the steel strip has a low yield ratio and high plasticity, expensive alloy elements such as niobium and chromium are added to increase the strength, but for wheel steel, it seems that the quality is excessive, and the cost is high, and the market competitiveness is poor.

[0003] In the face of the severe market situation of the steel industry, how to reduce the manufacturing cost of 510MPa-grade wheel steel, while ensuring the product quality, and make the production line play the maximum capacity becomes particularly important. Under the condition of ensuring production and equipment safety, the steel plate can finally be produced with the maximum efficiency, the lowest energy and alloy cost consumption while meeting the technical requirements of the steel plate performance. Based on this, it is very important to develop a 510MPa-grade wheel steel with low cost and high strength and toughness for steel plants to improve the profit level.

[0004] At present, in order to ensure the low-temperature toughness of 510MPa-grade wheel steel, a process with high alloy composition (Mn, Nb, Cr, etc.), thick intermediate blank and two-stage or even three-stage controlled rolling is usually adopted, which results in that the final rolling temperature of the steel plate may be controlled below 800℃, or even lower, and the rolling difficulty is greatly increased. Firstly, the rolling mill load, steel plate temperature uniformity, and plate shape control are all facing severe challenges, and secondly, the improvement of the performance of the steel plate mainly depends on the content of impurities such as phosphorus and sulfur in the steel, the content of alloy elements in the steel, and the control of key process parameters in the production process such as smelting and rolling. Therefore, how to organically combine the strengthening mechanisms such as phase transformation strengthening, solid solution strengthening and fine-grain strengthening, solve the problems existing in the production of 510MPa-grade wheel steel, reduce the alloy cost, improve the market competitiveness, and at the same time ensure the excellent strength and toughness, is the key to the development of low-cost 510MPa-grade wheel steel.

[0005] So far, there are few reports on the manufacture of low-cost 510MPa grade hot-rolled wheel steel and its manufacturing method at home and abroad. And the current prior art has the defect of high production cost, so it is not suitable for producing low-cost and excellent 510MPa grade wheel steel. The Chinese patent with application number 202310276851.8 discloses a manufacturing method of 490MPa grade Ti micro-alloyed wheel steel, but adopts a two-stage deep controlled rolling method, which leads to low production efficiency and obviously increases the manufacturing cost. At the same time, the low-temperature impact performance is not clear. SUMMARY

[0006] The purpose of the present application is to overcome the above-mentioned defects existing in the prior art, provide a low-cost 510MPa grade hot-rolled wheel steel and its preparation method, realize the production of 510MPa grade wheel steel plate with a thickness of 4-10mm and low cost using a continuous casting billet with a thickness of 150-200mm, and the steel plate has excellent low-temperature toughness and other characteristics, solves the problems of high alloy cost, etc., has low cost, high strength and toughness, and can ensure the service safety of the wheel steel plate.

[0007] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0008] A low-cost 510MPa grade hot-rolled wheel steel, comprising the following components by weight percentage: C: 0.08%-0.13%, Si: 0.1%-0.15%, Mn: 0.95%-1.20%, P≤0.020%, S≤0.015%, Al: 0.022%-0.033%, N: 0.0037%-0.0055%, the balance being Fe and unavoidable impurities, and 0.27≤(C+Mn / 6)≤0.32.

[0009] Optionally, the transverse tensile yield strength of the hot-rolled wheel steel is 360-410MPa, the tensile strength is 510-590MPa, the elongation is ≥25%, the -40℃ transverse Charpy impact energy is ≥135J, and the yield strength ratio is ≤0.8.

[0010] Optionally, the thickness of the hot-rolled wheel steel is 4-10mm.

[0011] The present application also discloses a preparation method of the low-cost 510MPa grade hot-rolled wheel steel as described above, comprising the following steps: molten steel smelting, LF refining, RH vacuum degassing, continuous casting, billet heating, rolling, cooling and coiling;

[0012] In the continuous casting, the overheat degree of the continuous casting is 8-12℃, the strand pulling rate is 0.8-1.1m / min; the current intensity of the electromagnetic stirring in the secondary cooling zone in the continuous casting stage is controlled to be 220-280A, the secondary cooling water quantity is 2.3L / kg-2.8L / kg, the heavy pressure is applied in the solidification end in the horizontal fan-shaped section, and the pressing amount of the continuous casting blank is 13-15mm; the blank is stacked for 48-72h after being discharged.

[0013] In the casting blank heating, the casting blank is sequentially discharged after the preheating section, the heating section and the soaking section; the temperature interval of the preheating section is 350-480℃, the temperature interval of the heating section is 1275-1288℃, and the temperature interval of the soaking section is 1130-1145℃; the time in the heating and soaking sections is 3-4h, the opening degree of the upper and lower burners in the soaking section is adjusted, the air-fuel ratio is controlled to be 1:1.7-1:2.2, the temperature difference between the upper and lower surfaces of the blank is ensured to be ≤15℃, and the time in the soaking section is 1-2h.

[0014] In the rolling, in the rough rolling stage, the reduction rate of each pass of the first three passes before the rough rolling is 30-50%, the descaling water is sprayed in the first three passes of the rolling, the time of each pass is 0.2-0.5min, and the pressure is 10-15MPa; the final rolling temperature in the finish rolling stage is 810-840℃; the total reduction rate in the finish rolling stage is >75%, and the reduction rate of the last two passes in the finish rolling stage is >18%.

[0015] In the cooling and coiling, the steel plate after rolling is taken to be slowly thrown, the throwing speed is 2-3.5m / s, the open cooling temperature range is controlled to be 690-730℃, the final cooling coiling temperature interval is 480-500℃, the cooling speed is 30-50℃ / s, the side spraying pressure and water quantity are 2-5MPa and 50-70m 3 / h respectively.

[0016] Optionally, in the molten steel smelting, the smelting raw materials are configured according to the chemical composition, the KR molten iron pretreatment is performed, the content of S is controlled to be ≤0.015%, and the slag is removed before entering the converter; the double-slag method is adopted to remove P in the converter smelting, the content of P is controlled to be ≤0.02%, the content of C at the end of the converter smelting is controlled to be 0.08%-0.13%, and argon gas is blown for 10-25min when the molten steel is discharged.

[0017] Optionally, in the LF refining and RH vacuum degassing, the RH vacuum is maintained for 30-40min.

[0018] Optionally, in the casting blank heating, the thickness of the casting blank is 150-200mm.

[0019] Optionally, in the rolling, the casting blank after being discharged is descaled by using high-pressure water for 1-2min before the rolling, the descaling machine pressure is 20-25MPa; the total reduction rate in the rough rolling stage is controlled to be 75%-85%, and the rough rolling passes are 3-5 passes.

[0020] Optionally, in the cooling and coiling, the side spraying pressure and water amount are 2-5 MPa and 50-70 m 3 / h.

[0021] Implementing the embodiments of the present application will have the following beneficial effects:

[0022] 1. In the smelting process, the KR molten iron pretreatment is used for deep desulfurization, and the slag is cleaned after the tapping, the double slag method is used in the converter to remove P, so that the P and S contents of the casting blank are low, the argon blowing time is controlled, and the RH vacuum degassing time is maintained, so that the defects such as center segregation, inclusions and H and O contents exceeding the standard caused by high Mn and C contents are overcome, and the plasticity and toughness of the steel plate are improved. Reducing the superheat and the continuous casting speed can improve the macro-segregation of the continuous casting blank, reduce the secondary dendrite arm spacing in the solidification structure of the continuous casting blank, help to reduce the segregation of the steel blank and reduce internal organizational defects. Controlling the electromagnetic stirring current intensity of the secondary cooling zone and the secondary cooling water amount can effectively reduce the average index of carbon segregation, inhibit the trend of segregation and center crack of the casting blank; the light press is poured at the solidification end, the center porosity level and segregation of the casting blank are effectively reduced, the heavy press is poured at the same time, the core grain is broken, and the strength and toughness of the subsequent steel plate are ensured; in addition, the steel blank is stacked after being discharged to reduce the aggregation of residual H and inhibit the generation of internal micro-cracks of the steel blank.

[0023] 2. The casting blank is heated: the temperature and time of the casting blank in the preheating section, the heating section and the soaking section are limited, the full diffusion of each element is ensured, the influence of composition segregation on the structure and performance is reduced, the high-temperature heating and air-fuel ratio of the heating section are provided, the temperature uniformity of each part of the casting blank is ensured, and the metal flow uniformity of the steel plate surface in the transverse and longitudinal directions is improved; combined with the composition of the steel blank, the heating temperature of the soaking section of the casting blank is reduced to reduce energy consumption; the temperature and time of the heating section and the soaking section are controlled to inhibit the excessive growth of the original austenite grains and increase the contribution of fine grain strengthening to the strength of the steel plate; in addition, low-temperature heating is adopted in the soaking section to avoid the two-stage rolling of the steel plate.

[0024] 3. The present application designs a reasonable chemical composition, reduces the alloy addition amount, replaces the precipitation strengthening with fine grain strengthening, does not add expensive alloy elements, adopts low-temperature heating + hot rolling manufacturing mode, greatly reduces the alloy cost and high-temperature deformation resistance in the rough rolling and finishing rolling stages, is beneficial to improve the per-pass reduction, and is beneficial to ensure the comprehensive performance of the ultra-steel plate.

[0025] 4. Through the first three passes before the rough rolling stage, the rolling mill capacity is exerted as much as possible, a large reduction rate is adopted, the dynamic austenite is promoted to crystallize, the original austenite grains are refined, the high-pressure water descaling of the rolling mill is adopted to generate a temperature gradient from the surface to the center of the steel plate, the core deformation and the uniformity of the structure distribution are promoted in the subsequent finishing rolling process, and the strength and toughness of the steel plate are improved. In addition, due to the adoption of the low-temperature heating process, the intermediate blank waiting in the finishing rolling stage is cancelled, the last two passes of rolling are ensured to be in the non-recrystallization temperature range of austenite, the large reduction rate is ensured to be adopted in the last two passes, the austenite grains are further refined, and the performance of the steel plate is improved.

[0026] 5. Slow steel throwing is adopted, the open cooling temperature is controlled, the steel plate is ensured to be in the ferrite + austenite state when entering the water, the cooling speed is controlled during the cooling process to ensure that the structure of the steel plate after cooling is ferrite + pearlite + a small amount of bainite, so as to ensure the coordination of deformation and improve the strength and toughness of the steel plate; through side injection, the control of the shape of the steel plate is beneficial to the improvement of the performance uniformity of the steel plate.

[0027] The present application reduces the alloy cost through simple component design, and realizes low-cost manufacturing of a 510MPa grade hot-rolled wheel steel plate with a thickness specification of 4-10mm through the regulation of steelmaking, continuous casting, heating and rolling and controlled cooling processes. The steel plate has good low-temperature toughness. The specific performance is that the yield strength of the transverse tensile property is between 360-410MPa, the tensile strength is between 510-590MPa, the yield strength ratio is ≤0.8, the elongation is ≥25%, and the transverse Charpy impact energy at-40℃ is ≥135J. DETAILED DESCRIPTION

[0028] The present application is further described below in combination with specific embodiments, but the present application is not limited in any way by the embodiments.

[0029] The present application discloses a low-cost 510MPa grade hot-rolled wheel steel, which comprises the following components by weight percentage: C: 0.08%-0.13%, Si: 0.1%-0.15%, Mn: 0.95%-1.20%, P≤0.020%, S≤0.015%, Al: 0.022%-0.033%, N: 0.0037%-0.0055%, the balance being Fe and unavoidable impurities, and 0.27≤(C+Mn / 6)≤0.32.

[0030] Specifically, the roles of the main elements in the chemical composition of the steel plate of the present application are as follows:

[0031] C: the most economical and basic strengthening element in steel, which has a significant effect on improving the strength of the steel through solid solution strengthening and precipitation strengthening, but increasing the C content has a negative impact on the plasticity, toughness and weldability of the steel. Therefore, the C content range is set to 0.08%-0.13% in the present application.

[0032] Mn: increase the strength of the steel by solid solution strengthening, while offsetting the loss of strength of the steel plate caused by the decrease of C content. In addition, it can also reduce the γ-α phase transition temperature, and further refine the ferrite grains, which helps to obtain fine low temperature phase transformation products and improve their toughness. However, increasing the content of Mn will exacerbate the center segregation of continuous casting billet and the formation of lamellar martensite, which is not conducive to the improvement of the low temperature toughness of the steel plate, and also affects the hole expansion performance of the steel plate. Therefore, the Mn content range of the present application is designed to be 0.95% to 1.20%.

[0033] Si: has the effects of steelmaking deoxidization and improving the strength of the matrix. However, excessive Si will reduce the toughness of the weld heat affected zone of the base material, and increasing the content of Si can purify the ferrite and reduce the content of pearlite, which is beneficial to reducing the Bauschinger effect of the base material. Therefore, the Si content in the present application is set to 0.1% to 0.15%.

[0034] N: In addition to forming fine NbN particles to refine austenite grains, N in steel has no other obvious effect, so it needs to be kept at a low content level. The N content range selected in the present application is 0.0033% to 0.0053%.

[0035] Al: is usually used as a deoxidizer in steel, and has the effect of refining the structure when AlN is formed. When the content of Al exceeds 0.035%, excessive alumina inclusions will reduce the cleanliness of the steel. If the content of Al is too low, the deoxidization will not be sufficient, so the lower limit of the content of Al is set to 0.019%.

[0036] P and S: are inevitable impurity elements in steel, and should be as low as possible. However, due to the consideration of smelting cost and process, they cannot be too low. Therefore, the upper limits of the contents of P and S in the present application are set to 0.020% and 0.015%.

[0037] The present application further controls 0.27≤(C+Mn / 6)≤0.32 to ensure that the wheel steel has good welding performance, the hardness of the heat affected zone is relatively low, and the possibility of welding crack is low. If it is not within this range, welding cracks are easy to occur, which will affect the welding performance of the wheel steel.

[0038] In a specific embodiment, the transverse tensile yield strength of the hot-rolled wheel steel is 360-410 MPa, the tensile strength is 510-590 MPa, the elongation is ≥25%, the -40℃ transverse Charpy impact energy is ≥135 J, and the yield strength ratio is ≤0.8.

[0039] In a specific embodiment, the thickness of the hot-rolled wheel steel is 4-10 mm.

[0040] The application further discloses a preparation method of the low-cost 510MPa-grade hot-rolled wheel steel.

[0041] In the molten steel smelting, smelting raw materials are configured according to chemical compositions, KR hot metal pretreatment is performed, the content of S is controlled to be less than or equal to 0.015%, and the molten steel is poured into a converter after slagging; a double-slag method is used to remove P in the converter smelting, the content of P is controlled to be less than or equal to 0.02%, the content of C is controlled to be 0.08% to 0.13% at the end of the converter smelting, and argon blowing is performed for 10 to 25 minutes when the molten steel is poured out. The argon blowing and settling before continuous casting can promote the removal of inclusions in the molten steel and improve the composition uniformity of the molten steel.

[0042] In the LF refining and RH vacuum degassing, the RH vacuum is maintained for 30 to 40 minutes.

[0043] In the continuous casting, the superheat is 8 to 12 DEG C, and the withdrawal rate is 0.8 to 1.1 m / min. Reducing the superheat and the withdrawal rate can improve the macrosegregation of the continuous casting billet, reduce the secondary dendrite arm spacing in the solidification structure of the continuous casting billet, help to reduce the segregation of the billet and reduce internal structure defects. The current intensity of electromagnetic stirring in the secondary cooling zone in the continuous casting stage is controlled to be 220 to 280 A, the secondary cooling water quantity is 2.3 L / kg to 2.8 L / kg, the average index of carbon segregation is reduced, the segregation is inhibited, the secondary cooling intensity is limited, the trend of the central crack of the billet is inhibited, the heavy pressure is poured into the solidification end in the horizontal fan-shaped section, the pressing amount of the continuous casting billet is 13 to 15 mm, the central porosity level and the segregation of the billet are reduced, the billet is stacked for 48 to 72 hours after being discharged, the aggregation of residual H is reduced, the internal micro-crack of the billet is inhibited, and the toughness of the steel plate is ensured.

[0044] S4, in the slab heating: the thickness of 150~200mm slab into the walking beam furnace for heating, in turn through the preheating section, heating section and soaking section after the furnace; wherein, the preheating section temperature interval is 350~480℃, to promote the uniformity of the microstructure in the slab, and promote the full diffusion of elements, heating section temperature interval is 1275~1288℃, soaking section temperature interval is 1130~1145℃; wherein, the heating and soaking section in the furnace time is 3~4h, adjust the opening degree of the upper and lower burner of the soaking section, control the air-fuel ratio 1:1.7~1:2.2, ensure the temperature difference between the upper and lower surface of the billet ≤15℃, and the soaking section time is 1~2h; improve the heating temperature, prolong the time in the furnace, further promote the diffusion of alloy elements Mn, C, reduce the influence of composition segregation on the structure and performance; at the same time, the heating section provides high temperature heating and controls the air-fuel ratio, ensures the uniformity of the temperature of each part of the slab, and improves the uniformity of the metal flow in the transverse and longitudinal directions of the steel plate; combined with the composition of the billet, by reducing the heating temperature of the billet soaking section, reducing energy consumption, limiting the temperature and time of the heating section and the soaking section to inhibit the excessive growth of the original austenite grain, ensure the contribution of fine grain strengthening to the strength of the steel plate, in addition, the soaking section adopts low temperature heating to avoid the rolling waiting time in the finishing rolling stage of the steel plate.

[0045] S5, in the rolling: before opening, the high pressure water is used to descale the billet after the furnace for 1~2min, the descaling machine pressure is 20~25MPa; in the rough rolling stage, the reduction rate of each pass of the first three passes is 30~50%, and the descaling water of the first three passes is sprayed before rolling, the time of each pass is 0.2~0.5min, and the pressure is 10~15MPa; the rolling mill capacity is used as far as possible in the first two passes before rolling, the large reduction rate is adopted to promote the dynamic crystallization of austenite, refine the original austenite grain, and the high pressure water descaling of the rolling mill is adopted to generate temperature gradient from the surface to the center of the steel plate, promote the deformation of the core and the uniformity of the structure distribution in the subsequent finishing rolling process, and improve the strength and toughness of the steel plate; the total reduction rate in the rough rolling stage is controlled in the range of 75%~85%, and the rough rolling pass is 3~5 passes; the total reduction rate in the finishing rolling stage is >75%, and the reduction rate of the last two passes in the finishing rolling stage is >18%; the finishing rolling temperature is 810~840℃. Due to the adoption of low temperature heating process, the intermediate billet waiting in the finishing rolling stage is cancelled, the last two passes of rolling are ensured to be in the non-recrystallization temperature interval of austenite, the large reduction rate is ensured to be adopted in the last two passes, the austenite grain is further refined, and the performance of the steel plate is improved.

[0046] S6, in the cooling and coiling: the slow steel throwing is adopted for the rolled steel plate, the throwing speed is 2~3.5m / s, the open cooling temperature range is controlled in the range of 690~730℃, the final cooling coiling temperature interval is 480~500℃, the cooling speed is 30~50℃ / s, the side spraying pressure and water quantity are 2~5MPa and 50~70m 3Slowly take the steel, control the open cooling temperature, ensure that the steel plate is in ferrite + austenite state, in the cooling process, control the cooling speed to ensure that the steel plate is composed of ferrite, pearlite and bainite after cooling, so as to ensure the coordination of deformation and improve the strength and toughness of the steel plate; through side injection, it is beneficial to the control of the shape of the steel plate and improves the uniformity of the performance of the steel plate.

[0047] The following is a specific embodiment

[0048] Table 1 is the chemical composition of the example steel, Table 2 is the smelting process system of the example steel, Table 3 is the heating system of the cast blank of the example steel and the high-pressure water descaling process before rolling of the continuous casting blank; Table 4 is the rolling parameter of the example steel; Table 5 is the controlled cooling and coiling process parameter of the example steel; and Table 6 is the performance index of the example steel plate.

[0049] Table 1 is the chemical composition of the example steel, Table 2 is the smelting process system of the example steel, Table 3 is the heating system of the cast blank of the example steel and the high-pressure water descaling process before rolling of the continuous casting blank; Table 4 is the rolling parameter of the example steel; Table 5 is the controlled cooling and coiling process parameter of the example steel; and Table 6 is the performance index of the example steel plate.

[0050]

[0051] Note: P≤0.02% in the steel; S≤0.015%.

[0052] Table 2 is the smelting process system of the example steel

[0053]

[0054] Table 3 is the heating system of the cast blank of the example steel and the high-pressure water descaling process before rolling of the continuous casting blank

[0055]

[0056] Table 4 is the rolling parameter of the example steel

[0057]

[0058] Table 5 is the controlled cooling and coiling process parameter of the example steel

[0059]

[0060] Table 6 is the performance index of the example steel plate

[0061]

[0062] It can be seen that, compared with the prior art, the component design, the steelmaking and continuous casting, the heating and the controlled rolling and controlled cooling scheme of the present application overcome the shortcomings of the prior art, and provide a 510MPa grade hot-rolled wheel steel with a thickness specification of 4-10mm and a manufacturing method thereof. The problems of high alloy cost are solved, and the steel plate has low cost, high strength and toughness, and can ensure the service safety of the wheel steel plate.

[0063] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A low-cost 510MPa grade hot-rolled wheel steel, characterized in that, Includes the following components by weight percentage: C: 0.08%~0.13%, Si: 0.1%~0.15%, Mn: 0.95%~1.20%, P≤0.020%, S≤0.015%, Al: 0.022%~0.033%, N: 0.0037%~0.0055%, with the balance being Fe and unavoidable impurities, and 0.27≤(C+Mn / 6)≤0.32; The hot-rolled wheel steel has a transverse tensile yield strength of 360-410 MPa, a tensile strength of 510-590 MPa, an elongation of ≥25%, a transverse Charpy impact energy of ≥135 J at -40℃, and a yield strength ratio of ≤0.

8. The method for preparing low-cost 510MPa grade hot-rolled wheel steel includes the following steps: steelmaking, LF refining, RH vacuum degassing, continuous casting, billet heating, rolling, cooling and coiling. In the continuous casting process: the superheat is 8-12℃, the billet pulling speed is 0.8-1.1m / min; the electromagnetic stirring current intensity in the secondary cooling zone is controlled at 220-280A, the secondary cooling water volume is 2.3L / kg-2.8L / kg, and in the horizontal fan-shaped section, under heavy pressure at the end of solidification, the billet reduction is 13-15mm; the billet is stacked for 48-72 hours after being removed from the line. In the billet heating process: the billet is passed through a preheating section, a heating section, and a soaking section in sequence before being taken out of the furnace; the temperature range of the preheating section is 350-480℃, the temperature range of the heating section is 1275-1288℃, and the temperature range of the soaking section is 1130-1145℃; the time in the heating and soaking sections is 3-4 hours; the opening degree of the upper and lower burners in the soaking section is adjusted to control the air-fuel ratio of 1:1.7-1:2.2, ensuring that the temperature difference between the upper and lower surfaces of the billet is ≤15℃, and the soaking section time is 1-2 hours; In the rolling process: during the roughing stage, the reduction rate of each of the first three passes is 30-50%, and the descaling water is sprayed onto the mill during the first three passes, with a time of 0.2-0.5 min and a pressure of 10-15 MPa; the finishing temperature is 810-840℃; the total reduction rate during the finishing stage is >75%, of which the reduction rate of the last two stands is >18%; During the cooling and coiling process: the rolled steel plate is subjected to slow steel throwing at a speed of 2 to 3.5 m / s, the initial cooling temperature range is controlled at 690 to 730℃, the final cooling coiling temperature range is 480 to 500℃, and the cooling rate is 30 to 50℃ / s.

2. The low-cost 510MPa grade hot-rolled wheel steel according to claim 1, characterized in that, The thickness of the hot-rolled wheel steel is 4~10mm.

3. The low-cost 510MPa grade hot-rolled wheel steel according to claim 1, characterized in that, In the steel smelting process: the smelting raw materials are prepared according to the chemical composition, and the KR hot metal is pretreated to control the S content ≤0.015%. After slag removal, the steel enters the converter. In the converter smelting process, the double slag method is used to remove P, and the P content is controlled ≤0.02%. At the end of the converter smelting process, the C content is controlled to be 0.08%~0.13%. Argon gas is blown for 10~25 minutes when tapping the steel.

4. The low-cost 510MPa grade hot-rolled wheel steel according to claim 1, characterized in that, During the LF refining and RH vacuum degassing processes, the RH vacuum is maintained for 30-40 minutes.

5. The low-cost 510MPa grade hot-rolled wheel steel according to claim 1, characterized in that, During the heating of the billet: the thickness of the billet is 150~200mm.

6. The low-cost 510MPa grade hot-rolled wheel steel according to claim 1, characterized in that, During the rolling process: before the start of rolling, the billet after exiting the furnace is descaled with high-pressure water for 1 to 2 minutes, and the descaling machine pressure is 20 to 25 MPa; the total reduction rate during the rough rolling stage is controlled at 75% to 85%, and the rough rolling passes are 3 to 5.

7. The low-cost 510MPa grade hot-rolled wheel steel according to claim 1, characterized in that, During the cooling and winding process, the side spray pressure and water flow rate are 2–5 MPa and 50–70 m³, respectively. 3 / h.

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