A bearing steel with good corrosion resistance and high strength and a production method and a heat treatment method thereof

Abstract

The application provides a bearing steel with good corrosion resistance and high strength and a production method and a heat treatment method thereof, and the composition is as follows: C 0.88%-1.00%, Si 0.40%-0.60%, Mn 0.3%-0.5%, Cr 1.5%-1.7%, Mo 0.1-0.25%, Nb 0.010%-0.025%, Ni 0.20%-0.30%, Ti<=0.0015%, Alt<=0.020%, P<=0.010%, S<=0.010%, T.O<=0.0015%, N<=0.0065%, and the rest is Fe and other inevitable impurities. Compared with the prior art, the application has good strength and plasticity and toughness of the product after heat treatment, and has excellent contact fatigue life and corrosion resistance through the composition and process design.

Description

Technical Field

[0001] This invention belongs to the technical field of bearing steel, and particularly relates to a high-strength bearing steel with good corrosion resistance, its production method, and its heat treatment method. Background Technology

[0002] Bearings are important and critical basic components in the equipment manufacturing industry. Bearing steel, with its excellent fatigue resistance, wear resistance and cold and hot working properties, is widely used in major equipment fields and emerging industries such as wind power generation, high-speed rail and aerospace.

[0003] In recent years, with the rapid development of industries such as automobiles and high-end manufacturing, the requirements for bearings have become increasingly stringent. Bearings not only need high strength, good plasticity, and ultra-long service life, but also high and uniform surface strength and low and uniform core hardness after heat treatment, capable of withstanding loads and alternating loads; they must also possess good corrosion resistance, remaining rust-free and uncorroded in the atmosphere.

[0004] Publication number CN 115323276 Chinese Patent A discloses a bearing steel with both high strength and high plasticity, and its production process. The composition is as follows: C 0.72-0.82%, Cr 2.8-3.8%, Ni 0.55-0.85%, N 0.02-0.025%, V 0.15-0.25%, Mo 0.2-0.25%, Mn 0.26-0.45%, Si 0.18-0.25%, Ta 0.01-0.15%, B 0.001-0.005%, S≤0.005%, P≤0.025%, O≤0.001%, Cu≤0.005%, Al≤0.05%, Nb≤0.3%, Ti≤0.005%, 0.15%≤V+B+Nb+Ti≤0.35%, with the balance being Fe and unavoidable impurities. This method reduces production costs and resource consumption, achieving a balance between high strength and high plasticity. However, the addition of more microalloying elements and rare earth elements results in higher costs.

[0005] Chinese patent CN 115233109 A discloses a narrow hardenability bearing steel and its production process. The composition is controlled to Sn+Sb+As+Pb≤0.035%. The process includes electric furnace smelting, LF refining, VD vacuum, continuous casting, heating, high-pressure water descaling, rolling, wire drawing, and Steyrmo line cooling. The LF refining uses a CAS slag system with appropriate basicity, fluidity, and foaming properties, combined with Al+CaC2 for deoxidation and desulfurization, and adsorption of inclusions. Cerium wire feeding reduces the content of residual elements. By controlling the narrow composition, low residual elements, and high purity of molten steel, and by continuously casting, heating, high-pressure water descaling, and controlled rolling and cooling, the austenite grain size, carbide network, carbide banding, and carbide liquid precipitation are improved, the pearlite nucleation rate is reduced, the transformation incubation period is increased, the C-curve is shifted to the right, the hardenability band is reduced, and the hardenability band is controlled at 1.5-2.5 HRC, thereby improving the dimensional stability and mechanical properties of heat treatment. However, the material lacks sufficient strength and toughness to meet the requirements for high strength and high toughness. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength bearing steel with good corrosion resistance and its production method. Through composition design and production process design, a bearing steel with excellent performance can be obtained.

[0007] This invention provides a heat treatment method for high-strength bearing steel with good corrosion resistance. By designing a matching heat treatment method, the tensile strength R of the product after heat treatment is improved. m ≥2200MPa, yield strength R P0.2 With a strength of ≥1400MPa and an elongation at break (A) ≥6%, it possesses high strength, high hardness, and high fatigue resistance. Furthermore, its corrosion resistance is 1.5 times that of conventional GCr15, demonstrating excellent corrosion resistance.

[0008] The specific technical solution of this invention is as follows:

[0009] A high-strength bearing steel with good corrosion resistance comprises the following components by weight percentage:

[0010] C 0.88%-1.00%, Si 0.40%-0.60%, Mn 0.3%-0.5%, Cr 1.5%-1.7%, Mo 0.1-0.25%, Nb 0.010%-0.025%, Ni 0.20%-0.30%, Ti ≤0.0015%, Alt ≤0.020%, P≤0.010%, S≤0.010%, TO≤0.0015%, N≤0.0065%, with the remainder being Fe and other unavoidable impurities.

[0011] The composition of the high-strength bearing steel with good corrosion resistance satisfies: 0.9 ≤ [C] / ([Si] + [Mn]) ≤ 1.4;

[0012] The composition of the high-strength bearing steel with good corrosion resistance satisfies: 1.80≤[Cr]+1.5×[Mo]+2.0×[Nb]≤2.05.

[0013] The composition of the high-strength bearing steel with good corrosion resistance satisfies: 2.7≤3.5×[Ni]+1.2×[Cr]+1.5×[Mo]≤3.4.

[0014] After heat treatment, the high-strength bearing steel with good corrosion resistance has the following microstructure: tempered bainite + tempered martensite + carbides + retained austenite, and the content of retained austenite is ≥20%.

[0015] The high-strength bearing steel with good corrosion resistance, after heat treatment, has a tensile strength R m ≥2200MPa, yield strength R P0.2 ≥1400MPa, elongation after fracture A≥6%; corrosion rate (72h)≤1.25g / (m²) 2 •h); Median contact fatigue life L 50 ≥7×10 7 Rated fatigue life L 10 ≥2.5×10 7 .

[0016] The present invention provides a method for producing high-strength bearing steel with good corrosion resistance, comprising the following process flow: batching → electric furnace smelting → LF furnace refining + RH vacuum refining → 250 square billet continuous casting → high-quality bar rolling → finishing → round steel finished product → packaging and warehousing.

[0017] The electric furnace smelting process is as follows: the final concentration of carbon (C) in the electric furnace is controlled at 0.15-0.25%, and the phosphorus content (P) is ≤0.010%. The process involves slag blocking during tapping. When 1 / 5 to 1 / 4 of the molten steel is tapped, refining slag and lime are added. When 1 / 4 to 1 / 3 of the molten steel is tapped, deoxidizer and alloying agent are added. After tapping, an appropriate amount of aluminum particles is evenly sprinkled onto the slag surface according to the amount of slag discharged.

[0018] The LF furnace refining process involves bottom blowing argon into the ladle throughout the process, with the argon flow rate determined by preventing molten steel from splashing out of the ladle. Pre-melted refining slag and lime are added to form slag, with a basicity of R4-8 and a white slag time of ≥20 minutes. Based on the composition analysis results before entering the LF furnace, alloys are added before and during the refining process to adjust the content of Si, Mn, Cr, Mo, Nb, and Ni.

[0019] The RH vacuum degassing process is as follows: In the initial stage of vacuum degassing, if the vacuum level is ≤100 Pa, the vacuum holding time should be ≥10 minutes; if 100 Pa < vacuum level ≤200 Pa, the vacuum holding time should be ≥15 minutes. In the later stage of vacuum degassing, the holding time should be ≥10 minutes. Based on the component analysis results from the initial stage of vacuum degassing, if component adjustments are needed in the middle stage, a vacuum holding time of at least 5 minutes must be maintained after the adjustment. Before leaving the station, a soft-blowing argon treatment is performed for at least 20 minutes.

[0020] The 250mm square billet continuous casting employs a fully protected casting process. A protective sleeve and argon seal are used between the ladle and tundish. The tundish uses a steel covering agent and argon blowing for protection. An immersion nozzle is used between the tundish and the crystallizer. A combination of secondary cooling, end-stage electromagnetic stirring, and light and heavy reduction is employed to eliminate center segregation in the billet. The primary cooling water pressure is 5.0-9.0 bar, the secondary cooling water pressure is 9.0-15.0 bar, and the light and heavy reduction is ≤35mm. The casting process maintains stable liquid level, casting speed, and superheat, resulting in defect-free billets. Using small square billets in continuous casting achieves low-segregation billets, ensuring uniform carbide composition in the bearing steel. Furthermore, it eliminates the need for initial billet preparation, allowing direct rolling of round steel and saving costs.

[0021] The superior bar rolling process: This invention can achieve the rolling of superior bars with a diameter of φ16-35mm. To ensure that C, Cr, Mo, and V elements are dissolved in austenite, the heating temperature is controlled at 1050-1150℃, and heating is slow to prevent cracking during heating. The soaking time is >35min to ensure that Cr, Mo, and V elements are fully dissolved. At the same time, to prevent decarburization sensitivity, the heating temperature cannot exceed 1150℃. After heating, the billet is descaled by high-pressure water and then rolled in a continuous rolling mill. The initial rolling temperature is 950-980℃, and the final rolling temperature is 750-800℃. The lower final rolling temperature ensures the formation of more dispersed nucleation sites and refining of grains. Rapid water cooling is used after rolling, with a maximum reddening temperature ≤680℃, thereby ensuring a uniform distribution of residual austenite in the microstructure after phase transformation.

[0022] The present invention provides a heat treatment method for high-strength bearing steel with good corrosion resistance, comprising the following process flow: spheroidizing annealing → blanking → forging → isothermal quenching → tempering → surface treatment → bearing.

[0023] The spheroidizing annealing process specifically involves: holding at 780-820℃ for 8-10 hours, then slowly cooling to 680-720℃ and holding for 4-6 hours, followed by furnace cooling to 650℃ and then air cooling to room temperature to form a spheroidized annealed structure of high-carbon bearing steel with a spheroidization grade of 2-4.

[0024] The slow cooling refers to cooling at a rate of 1℃ / min-2℃ / min.

[0025] The isothermal quenching treatment is specifically as follows: In order to obtain a high contact fatigue life and a high residual austenite content, and to inhibit the initiation and propagation of fatigue cracks, an isothermal quenching process is adopted. The quenching austenitizing temperature is 860-880℃, the holding temperature is 45-60 min, and then the temperature is held in a salt bath furnace at 200-215℃ for 3±0.2 h before air cooling. The microstructure after quenching is tempered bainite + tempered martensite + carbides + residual austenite, and the residual austenite content is ≥20%.

[0026] The tempering process involves a tempering temperature of 180-200℃, a holding time of 120±10 min, and air cooling.

[0027] After the above heat treatment, the microstructure of the product is: tempered bainite + tempered martensite + carbides + retained austenite, and the content of retained austenite is ≥20%; the tensile strength of the product R m ≥2200MPa, yield strength R P0.2 ≥1400MPa, elongation after fracture A≥6%, corrosion rate (72h)≤1.25g / (m²) 2 •h); Median contact fatigue life L 50 ≥7×10 7 Rated fatigue life L 10 ≥2.5×10 7 It possesses good strength and ductility, and exhibits excellent contact fatigue life, with a median fatigue life L... 50 and rated fatigue life L 10 All of them are more than twice that of conventional GCr15, and they also have excellent corrosion resistance, which is 1.5 times that of conventional GCr15.

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

[0029] C: C is essential for obtaining high strength and hardness. To obtain the high strength required for bearing steel, the C content must be above 0.95%. However, excessively high C content increases the aggregation of carbides, significantly reduces the hot strength of the steel, increases brittleness, and deteriorates the fatigue resistance and processing performance of the steel. Therefore, the C content should be controlled at 0.88%-1.00%.

[0030] Si: Si is the main deoxidizing element in steel and, as a solid solution hardening element, contributes to increased strength, significantly improving the deformation resistance of steel. However, excessive Si content will reduce the plasticity and toughness of steel, increase the reactivity of carbon, promote decarburization and graphitization during rolling and forging heating, make smelting difficult and increase the formation of inclusions, and worsen the fatigue resistance of steel. Therefore, the Si content should be controlled at 0.40%-0.60%.

[0031] Mn: Mn is an effective element for deoxidation and desulfurization, and it can also improve the hardenability and strength of steel. When the content is less than 0.3%, it is difficult to achieve these effects. However, if the Mn content is too high, Mn and P have a strong tendency to co-segregate at grain boundaries during tempering of quenched steel, promoting temper brittleness and deteriorating the toughness of the steel. Therefore, the Mn content should be controlled between 0.3% and 0.5%.

[0032] Cr: Cr effectively improves the hardenability of steel and has a secondary hardening effect. It is one of the main elements for achieving high strength in bearing steel, improving strength, hardness, and wear resistance without making the steel brittle. Cr can also reduce the activity of C, which can reduce the tendency of steel surface decarburization during heating, rolling, and heat treatment, thus contributing to high fatigue resistance. Furthermore, when added in combination with Mo and Ni, it can significantly improve the corrosion resistance of steel. However, excessive Cr content will deteriorate the toughness and cold workability of steel; therefore, the Cr content is controlled at 1.50-1.70%.

[0033] Mo: Mo is a strong carbide-forming element, effectively improving the hardenability of steel, its resistance to tempering, and its tempering stability. After heat treatment, it combines with carbon to form stable small-sized carbides, increasing the hardness of the steel and maintaining a certain level of wear resistance. Additionally, Mo can reduce the amount of hydrogen penetrating the steel surface, inhibiting the formation of corrosion pits and improving corrosion resistance. However, excessive Mo can easily lead to the formation of ferrite and lower the martensitic transformation point, making the steel difficult to harden. Therefore, the added Mo content should be 0.10-0.25%.

[0034] Nitrogen (Nb): Nitrogen (Nb) can significantly refine grain size. Grain refinement not only improves the strength and toughness of steel but also enhances its low-temperature performance. Furthermore, the finer grain size also improves corrosion resistance. The concentration of Nb can be controlled within the range of 0.010%-0.025%.

[0035] Ni: Ni stabilizes austenite, enhances the hardenability of steel, and improves low-temperature toughness. The addition of Ni also improves the rust layer structure, increases density and adhesion to the steel surface, thus enhancing the steel's corrosion resistance. The Ni content should be controlled between 0.20% and 0.30%.

[0036] Ti: Titanium readily forms titanium inclusions with nitrogen in high-carbon steel, which reduces the fatigue life of bearings made from bearing steel. Therefore, the Ti content must be strictly controlled, and Ti ≤ 0.0015% is required.

[0037] Alt: Alt is a strong deoxidizing element that also improves the oxidation resistance of steel. Alt can also refine austenite grains. However, excessive Alt content can lead to the formation of coarse carbonitrides, resulting in excessive brittle inclusions and affecting fatigue life. Alt content should be controlled at ≤0.020%.

[0038] S and P: Impurity elements such as S and P segregate at grain boundaries, which greatly reduces the resistance to delayed fracture. P can form micro-segregation during the solidification of molten steel, and then segregate at the grain boundaries during heating at the austenitizing temperature, which significantly increases the brittleness of the steel and thus increases its susceptibility to delayed fracture. S forms MnS inclusions and segregates at grain boundaries, thus increasing the susceptibility of the steel to delayed fracture. Therefore, the P and S contents should be controlled at P ≤ 0.010% and S ≤ 0.010%.

[0039] TO and N: Oxygen forms various oxide inclusions in steel. Under stress, stress concentration easily occurs at these oxide inclusions, leading to the initiation of microcracks and thus deteriorating the mechanical properties of the steel, especially its toughness and fatigue resistance. Therefore, in metallurgical production, measures must be taken to reduce its content as much as possible, controlling TO ≤ 0.0015%. N precipitates Fe4N in steel, with a slow diffusion rate, causing aging of the steel. At the same time, N also reduces the cold workability of the steel; N should be controlled ≤ 0.0065%.

[0040] To improve the strength and toughness of bearing steel, the chemical composition of the present invention is redesigned: (1) the C content is appropriately reduced to improve toughness, while the Si and Mn contents are increased. The content compensates for the reduction of C content to ensure strength. The chemical composition must meet 0.9≤[C] / ([Si]+[Mn])≤1.4; (2) Increase the Cr content and add Nb element to give full play to the secondary hardening effect, improve strength and wear resistance. At the same time, Nb element can refine the original austenite grain size. While improving strength, it can also improve toughness and obtain high contact fatigue strength. In addition, fine grains can also improve corrosion resistance. The chemical composition must meet 1.80≤[Cr]+1.5×[Mo]+2.0×[Nb]≤2.05; (3) Add Ni element to improve the toughness of steel on the one hand, and the passivation film formed by Ni element on the surface improves corrosion resistance. It can also improve corrosion resistance in combination with Cr and Mo elements. The chemical composition must meet 2.7≤3.5×[Ni]+1.2×[Cr]+1.5×[Mo]≤3.4.

[0041] Compared with existing technologies, the present invention, through composition and production process design, obtains bearing steel whose microstructure after the above heat treatment is tempered bainite + tempered martensite + carbides + retained austenite, with a retained austenite content ≥20%, tensile strength Rm ≥2200MPa, and yield strength R P0.2 It has a strength ≥1400MPa, elongation after fracture A≥6%, good strength and toughness, and excellent contact fatigue life, with a median fatigue life L. 50 and rated fatigue life L 10 All of them are more than twice that of conventional GCr15, and they also have excellent corrosion resistance, which is 1.5 times that of conventional GCr15. Detailed Implementation

[0042] Examples 1-5

[0043] A high-strength bearing steel with good corrosion resistance comprises the following composition by mass percentage as shown in Table 1. The balance not shown in Table 1 is Fe and unavoidable impurities.

[0044] Comparative Example 1 - Comparative Example 2

[0045] A high-strength bearing steel with good corrosion resistance comprises the following composition by mass percentage as shown in Table 1. The balance not shown in Table 1 is Fe and unavoidable impurities.

[0046] Table 1. Chemical composition (wt%) of the steels used in the examples and comparative examples.

[0047]

[0048] The high-strength bearing steel with good corrosion resistance in the above embodiments and comparative examples is produced according to the following process flow: batching according to the given chemical composition ratio → electric furnace smelting → LF furnace refining + RH vacuum refining → 250 square billet continuous casting → high-quality bar rolling → finishing → round steel finished product → packaging and warehousing.

[0049] The key points for specific operation are as follows:

[0050] 1) Electric furnace smelting: The final concentration of C in the electric furnace is controlled at 0.15-0.25%, and P≤0.010%; slag is blocked during tapping. When about 1 / 5 of the molten steel is tapped, refining slag and lime are added. When about 1 / 3 of the molten steel is tapped, deoxidizer and alloy are added. After tapping, an appropriate amount of aluminum particles are evenly sprinkled onto the slag surface according to the amount of slag.

[0051] 2) LF furnace refining: Argon is blown from the bottom of the ladle throughout the process, and the argon flow rate is based on the condition that the molten steel does not splash out of the ladle; pre-melted refining slag and lime are added to form slag, with a basicity of R4-8 and a white slag time of ≥20 minutes. Based on the composition analysis results before entering the LF furnace, alloys are added before and during the refining process to adjust the content of Si, Mn, Cr, Mo, Nb and Ni.

[0052] 3) RH Vacuum Degassing: In the initial stage of vacuum degassing, if the vacuum level is ≤100 Pa, the vacuum holding time should be ≥10 minutes; if the vacuum level is ≤200 Pa, the vacuum holding time should be ≥15 minutes. In the later stage of vacuum degassing, the holding time should be ≥10 minutes. Based on the composition analysis results in the initial stage of vacuum degassing, if composition adjustment is required in the middle stage, a vacuum holding time of at least 5 minutes must be ensured after the adjustment. Before leaving the station, perform soft-blowing argon treatment for ≥20 minutes.

[0053] 4) 250mm billet continuous casting: Utilizing small billets for continuous casting achieves low-segregation billets, ensuring uniform carbide composition in the bearing steel. It also eliminates the need for initial billet preparation, allowing direct rolling of round steel and saving costs. Full-process protective casting is employed. A protective sleeve and argon seal are used between the ladle and tundish. The tundish uses a steel covering agent and argon blowing for protection. An immersion nozzle is used between the tundish and the crystallizer. A combination of secondary cooling, end-of-line electromagnetic stirring, and light and heavy reduction is employed to eliminate center segregation in the billet. The primary cooling water pressure is 5.0-9.0 bar, the secondary cooling water pressure is 9.0-15.0 bar, and the light and heavy reduction is ≤35mm. Stable liquid level, casting speed, and superheat during casting ensure defect-free billets.

[0054] 5) High-quality bar rolling: This invention can achieve the rolling of high-quality bars with a diameter of φ16-35mm. In order to ensure that C, Cr, Mo, and V elements are dissolved in austenite, the heating temperature is controlled at 1050-1150℃ and heated slowly to prevent cracking during heating. The soaking time is >35min to ensure that Cr, Mo, and V elements are fully dissolved. At the same time, to prevent decarburization sensitivity, the heating temperature cannot exceed 1150℃. After heating, the billet is descaled by high-pressure water and then rolled in a continuous rolling mill. The initial rolling temperature is 950-980℃ and the final rolling temperature is 750-800℃. The lower final rolling temperature ensures the formation of more dispersed nucleation sites and refining of grains. Rapid water cooling is used after rolling, and the maximum reddening temperature is ≤680℃, thereby making the residual austenite in the microstructure after phase transformation uniformly distributed.

[0055] Table 2. Process parameters for each embodiment and comparative example produced according to the above method.

[0056]

[0057] The high-strength bearing steel with good corrosion resistance produced according to the above method is subjected to heat treatment. The process flow is as follows: spheroidizing annealing → blanking → forging → isothermal quenching → tempering → surface treatment → bearing.

[0058] Among them: spheroidizing annealing process: after holding at 780-820℃ for 8-10 hours, slowly cool to 680-720℃ at a cooling rate of 1℃ / min-2℃ / min and hold for 4-6 hours, then cool in the furnace to 650℃ and then air cool to room temperature to form a spheroidized annealed structure of high carbon bearing steel with a spheroidization grade of 2-4. Isothermal quenching: To obtain high contact fatigue life and the highest possible retained austenite content, thus inhibiting the initiation and propagation of fatigue cracks, isothermal quenching is adopted. The quenching austenitizing temperature is 860-880℃, held for 45-60 min, then held in a salt bath furnace at 200-215℃ for 3 h, followed by air cooling. The microstructure after quenching is bainite + martensite + carbides + retained austenite, with a retained austenite content ≥20%. Tempering is then performed at 180-200℃, held for 120 min, and air cooled. The microstructure is tempered bainite + tempered martensite + carbides + retained austenite, with a retained austenite content ≥20%.

[0059] The heat treatment process parameters for each embodiment and comparative example are shown in Table 3. Comparative example 3 in Table 3 is steel obtained using the chemical composition and production method of Example 1, except that the heat treatment adopts the conventional quenching and tempering process.

[0060] Table 3 Heat treatment parameters for each embodiment and comparative example

[0061]

[0062] After heat treatment, the embodiments and comparative examples of the present invention were tested according to JB / T 10510-2005 Contact Fatigue Test Method for Rolling Bearing Materials and GB / T 228.1-2010 Tensile Test Method for Metallic Materials at Room Temperature. The results are shown in Table 4.

[0063] Table 4 Performance of products in each embodiment and comparative example

[0064]

[0065] The underlined data above are data that do not meet the requirements of this invention.

[0066] Each embodiment of this application is manufactured according to the process described in this application, and the tensile strength R... m ≥2210MPa, yield strength R P0.2 With a strength ≥1430MPa and an elongation at fracture (A) ≥7%, the embodiment exhibits good strength and toughness, and a median fatigue life (L). 50 and rated fatigue life L 10All were more than twice that of conventional GCr15. A 72-hour salt spray corrosion test was conducted on the material. Compared to the example, the corrosion rate was less than 1.25, and the corrosion resistance was 1.5 times that of conventional GCr15. Comparative Example 1, with [C] / ([Si]+[Mn]), is not within the scope of this invention, and the finished product strength did not meet the design requirements. Comparative Example 2, with [Cr]+1.5×[Mo]+2.0×[Nb] and 3.5×[Ni]+1.2×[Cr]+1.5×[Mo], is also not within the scope of this invention, and Ni element was not added; therefore, the fatigue strength and corrosion resistance did not meet the design requirements. Comparative Example 2, using the same heat treatment process, had a lower residual austenite content. Comparative Example 3 used the chemical composition and production method of Example 1, but the conventional quenching and tempering process (i.e., without salt bath furnace holding) resulted in a microstructure dominated by martensite, and the contact fatigue life was significantly lower than that of the example.

Claims

1. A high-strength bearing steel with good corrosion resistance, characterized in that, The high-strength bearing steel with good corrosion resistance comprises the following components by weight percentage: C 0.88%-1.00%, Si 0.40%-0.60%, Mn 0.3%-0.5%, Cr 1.5%-1.7%, Mo 0.1-0.25%, Nb 0.010%-0.025%, Ni 0.20%-0.30%, Ti ≤0.0015%, Alt ≤0.020%, P≤0.010%, S≤0.010%, TO≤0.0015%, N≤0.0065%, with the remainder being Fe and other unavoidable impurities; The composition of the high-strength bearing steel with good corrosion resistance satisfies: 0.9 ≤ [C] / ([Si] + [Mn]) ≤ 1.4; The composition of the high-strength bearing steel with good corrosion resistance satisfies: 1.80≤[Cr]+1.5×[Mo]+2.0×[Nb]≤2.05; The composition of the high-strength bearing steel with good corrosion resistance satisfies: 2.7 ≤ 3.5 × [Ni] + 1.2 × [Cr] + 1.5 × [Mo] ≤ 3.4; The high-strength bearing steel with good corrosion resistance is subjected to heat treatment, and the process flow is as follows: spheroidizing annealing → blanking → forging → isothermal quenching → tempering → surface treatment → bearing. The isothermal quenching process specifically involves: quenching at an austenitizing temperature of 860-880℃, holding at that temperature for 45-60 minutes, followed by holding at a salt bath furnace at 200-215℃ for 3±0.2 hours and then air cooling.

2. A method for producing high-strength bearing steel with good corrosion resistance as described in claim 1, characterized in that, The production method includes the following process flow: raw material batching → electric furnace smelting → LF furnace refining + RH vacuum refining → 250 square billet continuous casting → high-quality bar rolling → finishing → round steel finished product → packaging and warehousing.

3. The production method according to claim 2, characterized in that, The rolling of the superior bars is as follows: the heating temperature is controlled at 1050-1150℃, the initial rolling temperature is 950-980℃, the final rolling temperature is 750-800℃, and the maximum reddening temperature is ≤680℃.

4. A heat treatment method for high-strength bearing steel with good corrosion resistance as described in claim 1, characterized in that, The heat treatment method includes spheroidizing annealing, specifically: holding at 780-820℃ for 8-10 hours, cooling to 680-720℃ at a cooling rate of 1℃ / min-2℃ / min, holding for 4-6 hours, then cooling in the furnace to 650℃ and then air-cooling to room temperature. The heat treatment method includes isothermal quenching, specifically: quenching austenitizing temperature of 860-880℃, holding at that temperature for 45-60 min, then holding at 200-215℃ in a salt bath furnace for 3±0.2 h followed by air cooling.

5. The heat treatment method according to claim 4, characterized in that, The heat treatment method includes tempering at a temperature of 180-200℃, holding at that temperature for 120±10 min, and air cooling.

6. The heat treatment method according to claim 4 or 5, characterized in that, After heat treatment, the microstructure of the product is: tempered bainite + tempered martensite + carbides + retained austenite, with the retained austenite content ≥20%; the tensile strength R of the product is... m ≥2200MPa, yield strength R P0.2 ≥1400MPa, elongation after fracture A≥6%; 72h salt spray corrosion rate≤1.25g / (m²) 2 •h); Median contact fatigue life L 50 ≥7×10 7 Rated fatigue life L 10 ≥2.5×10 7 .

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