High-temperature-resistant and high-fatigue-performance bearing steel and preparation method thereof

Abstract

The invention relates to high-temperature-resistant and high-fatigue-performance bearing steel and a preparation method thereof. The invention relates to bearing steel with high temperature resistance and high fatigue performance. The bearing steel comprises the following chemical components in percentage by weight: 1.20%-1.50% of C, 0.2%-1.0% of Si, 0.1%-1.0% of Mn, 3.0%-5.0% of Cr, 9.0%-12.0% of Mo, 1.50%-2.50% of V, 5.0%-7.0% of W, 1t of S and the balance of Fe. 0.01%, P: lt; 0.01%, O: lt; 0.025%, N: lt; 0.01%, H: lt; 0.0001%, and the balance being Fe. The novel powder metallurgy high-temperature bearing steel has the beneficial effects that through the alloying design of C, Si, Mn, Cr, Mo, V and W, the room-temperature hardness reaches 65 HRC or above, meanwhile, the 600-DEG C high-temperature hardness is larger than 58 HRC, and under the guarantee of the scientific preparation method and the heat treatment process, the novel powder metallurgy high-temperature bearing steel has higher strength, good obdurability and good high-temperature resistance and fatigue resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to a high-temperature resistant and high-fatigue performance bearing steel and a preparation method thereof. Background Art

[0002] With the development of aviation, aerospace, medical equipment and other equipment, bearings are required to operate in harsh environments such as high temperature and high load, and also require high reliability and long life, which requires bearing steel to have high high temperature hardness, high strength and toughness, high microstructure refinement and homogenization, and high contact fatigue life. The service temperature of high temperature bearing steels such as 8Cr4Mo4V, Cr14Mo4VG13Cr4Mo4NI4V reported so far is generally below 500℃, which is difficult to meet the service hardness and life requirements at a high temperature of 600℃.

[0003] In addition, high temperature resistant bearing materials generally contain high content of alloying elements such as C, Mo, W, and V, which are easy to form large particles and network eutectic carbides. Traditional ingot forging and smelting lead to component segregation and uneven organization, which are difficult to eliminate by subsequent forging heat treatment. Large particle carbides and component segregation will seriously affect the fatigue life of the material. Powder metallurgy technology can significantly improve the component segregation, organizational uniformity and elimination of large particles and network carbides in the preparation process of high carbon and high alloy materials, but the cleanliness level of powder steel is low, which affects the contact fatigue and other properties of the material.

[0004] In summary, the motivation for the invention is to provide a high temperature bearing steel with high temperature resistance (≥600°C), low oxygen content, high cleanliness, powder metallurgy and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a high temperature bearing steel with high temperature resistance (≥600°C), low oxygen content, high cleanliness, powder metallurgy and a preparation method thereof, which has good high temperature hardness, toughness, and high cleanliness.

[0006] The high temperature resistant and high fatigue performance bearing steel provided by the present invention has the following technical solutions:

[0007] A high temperature resistant and high fatigue performance bearing steel, wherein the chemical composition range of the bearing steel is as follows by weight percentage: C: 1.20% to 1.50%, Si: 0.2% to 1.0%, Mn: 0.1% to 1.0%, Cr: 3.0% to 5.0%, Mo: 9.0% to 12.0%, V: 1.50% to 2.50%, W: 5.0% to 7.0%, S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%, and the balance is Fe.

[0008] Furthermore, the room temperature hardness of the bearing steel after quenching and tempering is ≥65HRC, and the high temperature hardness at 600°C is ≥58HRC; the room temperature tensile strength of the bearing steel after quenching and tempering is ≥2100MPa, and the unnotched impact energy is ≥20J.

[0009] A method for preparing high temperature resistant and high fatigue performance bearing steel comprises the following steps:

[0010] Step 1: The bearing steel master alloy is melted by vacuum induction method or vacuum induction furnace + vacuum consumable furnace method, and the ingot is cast to obtain a high-purity master alloy casting rod with low oxygen content and high cleanliness. After the casting rod is peeled and the riser is cut off, the high-cleanliness master alloy is obtained;

[0011] Step 2: Prepare high-purity alloy powder by vacuum gas atomization. -3 The master alloy was melted in a Pa environment, and high-purity argon gas was used for atomization. After the powder was sieved, a high-purity alloy steel metal powder of 0 to 150 μm was obtained; the alloy steel powder was packaged in a sleeve and heated at 450 ° C and 1 × 10 -3 Pa high vacuum degassing for 16-20h, then brazing and sealing the jacket to ensure no leakage and air leakage; put it into a hot isostatic press, the hot isostatic pressing process is heating the jacket with the furnace at 1080-1200℃ and 110-150MPa pressure for 1-5h, then cooling to below 500℃ at a rate of <40℃ / h and air cooling to obtain a dense hot isostatic pressed sintered blank;

[0012] Step 3: After removing the jacket from the sintered blank and heating it at 1200°C for 2 hours, the blank is forged or hot-rolled by using one or more deformation equipment such as a forging hammer, a press, and a rolling mill, and the forging temperature ranges from 1180 to 900°C; a new type of high-temperature powder bearing steel forging material with a compression ratio of 3 to 10 is obtained; and the carbide and matrix structure are refined and homogenized;

[0013] Step 4: After forging, the alloy steel is annealed. The annealing process is heating at 840-900°C for 1-4 hours, then cooling to 550°C at a rate of <20°C / h, and air cooling. The hardness after annealing is ≤340HBW. Subsequently, the surface is polished to obtain powder high-temperature bearing steel bars. The impurity element composition ranges of P, S, O, N, and H are as follows: S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%.

[0014] Furthermore, the heat treatment process of the bearing steel is to keep the temperature at 1150°C to 1220°C for 0.5 to 1 hour, then oil quench, and then keep the temperature at 500 to 600°C for 1 to 4 hours, and then air cool and temper for 2 or 3 times.

[0015] Furthermore, in step one: a vacuum induction furnace + vacuum consumable furnace method is used to melt the master alloy, and the oxygen content of the master alloy is ≤0.0007%, the nitrogen content is ≤0.002%, and H: <0.0001%; ​​a high-purity master alloy cast rod with low oxygen content and high cleanliness is obtained.

[0016] Furthermore, in step 2: the oxygen content of the metal powder of the high-purity alloy steel is ≤0.025%, the nitrogen content is ≤0.01%, and H: <0.0001%, thereby obtaining alloy steel powder with fine particle size and high cleanliness.

[0017] Furthermore, in step 2: the alloy steel powder is packaged by a cylindrical sheath.

[0018] The main functions of the above chemical elements are as follows:

[0019] C: Main strengthening element, produces interstitial solid solution strengthening, and obtains high-hardness martensite. Together with Cr, W, Mo, and V alloy elements, it forms carbides, which includes the process of dissolution, precipitation, aggregation, and transformation of carbides. The precipitation process is mainly in the two processes of solidification and tempering, and primary carbides and secondary carbides are precipitated respectively. In general, primary carbides are relatively coarse, while secondary carbides are very fine and dispersed, which is the main reason for the secondary hardening of high-temperature steel. Too high C content will lead to coarse carbides and excessive content, increase the unevenness of carbides and hot isostatic pressing solidification sintering, which is not conducive to the densification of hot isostatic pressing billets and the wear resistance and fatigue properties of finished steel. Low C content will make the number of carbides insufficient, fail to achieve the expected strengthening effect, and reduce the high-temperature hardness and fatigue properties of steel. In order to ensure that the steel has sufficient high-temperature hardness level and wear resistance requirements, the C content is controlled at 1.20% to 1.50%.

[0020] Cr: The Cr content in high carbon and high temperature bearing steel is preferably about 4wt%, which can effectively improve the wear resistance and hardenability of the steel. In addition to a small amount of Cr existing in M6C and MC carbides, Cr will also form a large amount of M6C with Fe and Cr as the main alloying elements during the spheroidizing annealing process. 23 C6 carbides, and promotes these carbides to be almost completely dissolved in austenite during the quenching heating process, thereby enhancing the alloying of austenite and improving the hardenability of steel. In addition, 4wt% Cr content can also enhance the oxidation resistance, corrosion resistance and decarburization resistance of steel, so the Cr content is controlled at 3.0% to 5.0%.

[0021] Si: Adding silicon to high-carbon high-temperature bearing steel will inhibit the precipitation and growth of carbides in sintered high-speed steel, improve the distribution and morphology of carbides, and obtain dispersed carbide structure. At the same time, it improves the sintering density of high-speed steel, reduces the austenite content in the matrix, increases the martensite content, and improves the hardness. However, if the Si content is too high, the plasticity and toughness of the steel will be significantly reduced. The Si content is controlled at 0.2% to 1.0%.

[0022] Mn: A strong element that increases hardenability and improves the uniformity and consistency of the quenched structure. However, too high a content will increase the content of retained austenite and reduce the strength of the steel. The Mn content is controlled at 0.1% to 1.0%.

[0023] Mo: Mo is the most important alloying element for improving the strength and hot hardness of high-temperature bearing steel. It has a solid solution strengthening effect when melted in the matrix. Its cast eutectic carbide is different from the fishbone-shaped M6C carbide of high tungsten, and is in a thinner lamellar shape. It can be decomposed during heat preservation or subsequent hot deformation processing, and is easy to break evenly. Therefore, high-molybdenum steel has higher thermoplasticity and toughness than high-tungsten steel; it greatly improves the strength and hardness of steel, and can also improve the stability of carbides at high temperatures. The Mo content is controlled at 9.0% to 12.0%.

[0024] W can form (W, Fe) with Fe and C in high speed steel 23 C6 and (W, Fe)6C, two special carbides with high hardness and high wear resistance, are one of the most important hard phases to improve the high temperature hardness and wear resistance of high temperature steel. Among them, the fine tungsten carbide particles are mostly distributed at the grain boundaries to prevent the growth of grains. W can increase the decomposition temperature of martensite during tempering after quenching and delay the aggregation of decomposition products, so that the steel can still maintain extremely high hardness at a temperature of 600°C, even if the high-speed steel has red hardness. When W is solid-dissolved in the high-speed steel matrix, it can effectively improve the tempering stability of the steel. The W content is controlled at 5.0% to 7.0%.

[0025] V: Vanadium is an important strong carbide forming element, which can form stable and fine MC type carbides during tempering. In addition, together with Mo and Nb, it can form composite carbides with high thermal stability, thereby improving the mechanical properties of high temperature steel such as hardness, wear resistance, red hardness and cutting performance. When the V content is less than 1%, due to the low V content, the red hardness and wear resistance of high speed steel are also low, and the secondary hardening effect is not good. When the V content is higher than 3%, the grindability is poor, resulting in high grinding process costs in subsequent processing. The V content is controlled at 1.50% to 2.50%.

[0026] The remaining elements in the high temperature bearing steel of the present invention are Fe, and the impurity elements in the alloy such as S, P, O, N, H, etc. must be strictly controlled, P does not exceed 0.01%, S does not exceed 0.01%, O: <0.025%, N: <0.01%, H: <0.0001%.

[0027] The implementation of the present invention includes the following technical effects:

[0028] The high temperature resistant and high fatigue performance powder high temperature bearing steel of the present invention has a room temperature hardness of more than 65HRC through the alloying design of C, Si, Mn, Cr, Mo, V, and W, and a high temperature hardness of 600℃>58HRC. Under the guarantee of scientific preparation method and heat treatment process, the new powder metallurgy high temperature bearing steel has higher strength, good toughness, good high temperature resistance and fatigue performance. Compared with the prior art, the service temperature and fatigue performance of bearing steel are improved, and it has good promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the annealed structure of the high temperature resistant and high fatigue performance bearing steel of Example 1 of the present invention.

[0030] Figure 2 This is the quenched and tempered structure of the high temperature resistant and high fatigue performance bearing steel of Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below in conjunction with embodiments and drawings. It should be pointed out that the described embodiments are only intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0032] Example 1

[0033] The preparation method of the high temperature resistant and high fatigue performance bearing steel of this embodiment comprises the following steps:

[0034] Step 1: According to the ratio of each element in the alloy, high-purity alloy raw materials are used for batching, and the raw material ratio is C: 1.20%-1.50%, Si: 0.2%-1.0%, Mn: 0.1%-1.0%, Cr: 3.0%-5.0%, Mo: 9.0%-12.0%, V: 1.50%-2.50%, W: 5.0%-7.0%, and the balance is Fe. In this embodiment, vacuum induction and other methods are used to melt the master alloy, and the ingot is cast to obtain a high-purity master alloy casting rod with low oxygen content and high cleanliness. A 50-kilogram vacuum induction furnace is used to prepare a 50-kilogram alloy steel casting rod, and the high-purity master alloy rod is obtained after the steel ingot is peeled and the riser is cut off.

[0035] Step 2: Prepare high-purity alloy powder by vacuum gas atomization (VIGA) method. - 3The master alloy was melted in a Pa environment, and high-purity argon (purity 99.99%) was used for atomization. After the powder was sieved, a high-purity alloy steel metal powder of 0 to 150 μm was obtained. The powder was then packaged into a cylindrical iron sleeve and heated at 450 ° C and 1×10 - 3 Pa high-temperature vacuum degassing is carried out for 20 hours, and then the sleeve is brazed and sealed to ensure no welding leakage and air leakage, and then put into a hot isostatic pressing machine. The hot isostatic pressing process is that the sleeve is heated with the furnace at 1090℃ and 120MPa pressure for 4 hours, and then the temperature is controlled and cooled to below 500℃ at a rate of <40℃ / h, and then air-cooled to obtain a dense hot isostatic pressed sintered blank.

[0036] Step 3: After removing the jacket from the sintered billet and heating it at 1200°C for 2 hours, the billet is forged or hot-rolled using one or more deformation equipment such as a forging hammer, a press, and a rolling mill. The forging temperature ranges from 1180 to 900°C. A new type of high-temperature powder bearing steel forging with a compression ratio of 5 is obtained. The carbide and matrix structure are refined and homogenized.

[0037] Step 4: After forging, the alloy steel is annealed, and the annealing process of the invention steel is required: annealing of forged materials. Another annealing process is to heat and keep at 840-900℃ for 1-4h, then cool to 550℃ at a rate of <20℃ / h, and air cool; the hardness after annealing is ≤340HBW; then the surface is polished to obtain powder high-temperature bearing steel bars. The impurity element composition ranges of P, S, O, N, and H in bearing steel are as follows: S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%.

[0038] Then, chemical analysis, structure and hardness samples were taken from the bars, and room temperature hardness and high temperature hardness properties were measured after quenching and tempering. The chemical composition results are shown in Table 1.

[0039] Table 1 Chemical composition of bearing steel of Example 1 (wt.%)

[0040]

[0041] The sample heat treatment process 1 is as follows:

[0042] Quenching: 1190℃, keep warm for 30min, oil cooling;

[0043] Tempering: 560℃, keep warm for 1 hour, air cool. Temper twice.

[0044] The annealing structure and quenching and tempering structure of the test steel are as follows Figure 1 and Figure 2As shown. After annealing, the structure is uniformly dispersed, no obvious large carbide particles are found, and the carbide particle size is <3 microns. The uniform and fine structure ensures the stability of performance and high fatigue performance. After quenching and tempering, part of the carbide is dissolved, and tempered martensite and tempered precipitated carbides are obtained after quenching and tempering.

[0045] The mechanical properties are shown in Table 2 and Table 3. The room temperature hardness of the obtained 1# high temperature bearing steel after quenching and tempering is ≥65HRC, and the high temperature hardness at 600℃ is ≥58HRC; the high room temperature and high temperature hardness can ensure its high temperature resistance and high fatigue performance at 600℃. The room temperature tensile strength of the obtained high temperature bearing steel after quenching and tempering is ≥2100MPa, and the unnotched impact energy is ≥20J. Compared with ultra-high carbon steel, it has good strength and toughness.

[0046] Table 2 Room temperature and high temperature Rockwell hardness, HRC

[0047]

[0048] Table 3 Mechanical properties at room temperature

[0049]

[0050] The heat treatment process 2 of the sample is as follows:

[0051] Quenching: 1200℃, keep warm for 30min, oil cooling;

[0052] Tempering: 550℃, keep warm for 2 hours, air cool. Temper twice.

[0053] The mechanical properties are shown in Tables 4 and 5. The room temperature hardness of the obtained 2# high temperature bearing steel system 2 after quenching and tempering is ≥65HRC, and the high temperature hardness at 600℃ is ≥57HRC.

[0054] Table 4 Room temperature and high temperature Rockwell hardness, HRC

[0055]

[0056] Example 2

[0057] The preparation method of the high temperature resistant and high fatigue performance bearing steel of this embodiment comprises the following steps:

[0058] Step 1: According to the ratio of each element in the alloy, high-purity alloy raw materials are used for mixing, and the raw material ratio is C: 1.20%-1.50%, Si: 0.2%-1.0%, Mn: 0.1%-1.0%, Cr: 3.0%-5.0%, Mo: 9.0%-12.0%, V: 1.50%-2.50%, W: 5.0%-7.0%, and the balance is Fe. This embodiment adopts a vacuum induction furnace + vacuum consumable furnace (double vacuum) method to melt the master alloy, and the prepared master alloy has an oxygen content of ≤0.0007%, a nitrogen content of ≤0.002%, and H: <0.0001%; ​​a high-purity master alloy casting rod with low oxygen content and high cleanliness is obtained.

[0059] Step 2: The master alloy bar is first subjected to vacuum gas atomization powder making: at a vacuum degree of 1×10 -3 The master alloy was melted in a Pa environment and atomized with high-purity argon (purity 99.99%). The prepared alloy steel powder was screened to obtain alloy powder with a particle size of 0 to 53 μm. The alloy steel powder was packaged in a cylindrical package and heated at 450 °C and 1 × 10 -3 Pa high-temperature vacuum degassing treatment is carried out for 17 hours, and then the sleeve is brazed and sealed to ensure that there is no welding leakage and air leakage; it is placed in a hot isostatic pressing machine. The hot isostatic pressing process is that the sleeve is heated with the furnace at 1180℃ and 140MPa pressure for 2 hours, and then the temperature is controlled and cooled to below 500℃ at a rate of <40℃ / h, and then air-cooled to obtain a dense hot isostatic pressed sintered blank.

[0060] Step 3: After removing the jacket from the sintered billet and heating it at 1200°C for 2 hours, the billet is forged or hot-rolled using one or more deformation equipment such as a forging hammer, a press, and a rolling mill. The forging temperature ranges from 1180 to 900°C. A new type of high-temperature powder bearing steel forging with a compression ratio of 8 is obtained. The carbide and matrix structure are refined and homogenized.

[0061] Step 4: After forging, the alloy steel is annealed, requiring the annealing process of the invention steel: annealing of forged materials. Another annealing process is heating at 840-900℃ for 1-4h, then cooling to 550℃ at a rate of <20℃ / h, and air cooling; the hardness after annealing is ≤340HBW; then the surface is polished to obtain powder high temperature bearing steel bars.

[0062] Then, chemical analysis, structure and hardness samples were taken from the bars, and the room temperature hardness and high temperature hardness properties were measured after quenching and tempering. The chemical composition results are shown in Table 5.

[0063] Table 5 Chemical composition of bearing steel of Example 2 (wt.%)

[0064]

[0065] The heat treatment process of the sample is as follows:

[0066] Quenching: 1190℃, keep warm for 30min, oil cooling;

[0067] Tempering: 560℃, keep warm for 1 hour, air cool. Temper twice.

[0068] The mechanical property results are shown in Tables 6 and 7. The room temperature hardness of the obtained 3# high temperature bearing steel after quenching and tempering is ≥66HRC, and the high temperature hardness at 600℃ is ≥58HRC; the high room temperature and high temperature hardness can ensure its high temperature resistance and high fatigue performance at 600℃. The room temperature tensile strength of the obtained high temperature bearing steel after quenching and tempering is ≥2300MPa, and the unnotched impact energy is ≥22J. Compared with Example 1, Example 2 improves the fracture strength through fine powder process control, and has good impact toughness.

[0069] Table 6 Room temperature and high temperature Rockwell hardness, HRC

[0070]

[0071] Table 7 Mechanical properties at room temperature

[0072]

[0073] The high temperature resistant and high fatigue performance powder high temperature bearing steel of the present invention, through the alloying design of C, Si, Mn, Cr, Mo, V, and W, reaches above 65HRC at room temperature, and the high temperature hardness at 600℃ is greater than 58HRC. Under the guarantee of scientific preparation method and heat treatment process, the new powder metallurgy high temperature bearing steel has higher strength, good toughness, good high temperature resistance and fatigue performance. Compared with the prior art, the service temperature and fatigue performance of bearing steel are improved, and it has good promotion and application value.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A high temperature resistant and high fatigue performance bearing steel, characterized in that: The chemical composition range of the bearing steel is as follows by weight percentage: C: 1.20% to 1.50%, Si: 0.2% to 1.0%, Mn: 0.1% to 1.0%, Cr: 3.0% to 5.0%, Mo: 9.0% to 12.0%, V: 1.50% to 2.50%, W: 5.0% to 7.0%, S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%, and the balance is Fe.

2. The high temperature resistant and high fatigue performance bearing steel according to claim 1, characterized in that: The room temperature hardness of the bearing steel after quenching and tempering is ≥65HRC, and the high temperature hardness at 600°C is ≥58HRC; the room temperature tensile strength of the bearing steel after quenching and tempering is ≥2100MPa, and the unnotched impact energy is ≥20J.

3. A method for preparing high temperature resistant and high fatigue performance bearing steel, characterized in that: The following steps are involved: Step 1: The bearing steel master alloy is melted by vacuum induction method or vacuum induction furnace + vacuum consumable furnace method, and the ingot is cast to obtain a high-purity master alloy casting rod with low oxygen content and high cleanliness. After the casting rod is peeled and the riser is cut off, the high-cleanliness master alloy is obtained; Step 2: Prepare high-purity alloy powder by vacuum gas atomization. -3 The master alloy was melted in a Pa environment, and high-purity argon gas was used for atomization. After the powder was sieved, a high-purity alloy steel metal powder of 0 to 150 μm was obtained; the alloy steel powder was packaged in a sleeve and heated at 450 ° C and 1 × 10 -3 Pa high vacuum degassing for 16-20h, then brazing and sealing the jacket to ensure no leakage and air leakage; put it into a hot isostatic press, the hot isostatic pressing process is heating the jacket with the furnace at 1080-1200℃ and 110-150MPa pressure for 1-5h, then cooling to below 500℃ at a rate of <40℃ / h and air cooling to obtain a dense hot isostatic pressed sintered blank; Step 3: After removing the jacket from the sintered blank and heating it at 1200°C for 2 hours, the blank is forged or hot-rolled by using one or more deformation equipment such as a forging hammer, a press or a rolling mill, and the forging temperature ranges from 1180 to 900°C; a new high-temperature powder bearing steel forging material with a compression ratio of 3 to 10 is obtained; and the carbide and matrix structure are refined and homogenized; Step 4: After forging, the alloy steel is annealed. The annealing process is heating at 840-900°C for 1-4 hours, then cooling to 550°C at a rate of <20°C / h, and air cooling. The hardness after annealing is ≤340HBW. Subsequently, the surface is polished to obtain powder high-temperature bearing steel bars. The impurity element composition ranges of P, S, O, N, and H are as follows: S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%.

4. The method for preparing a high temperature resistant and high fatigue performance bearing steel according to claim 3, characterized in that: The heat treatment process of the bearing steel is to keep the temperature at 1150° C. to 1220° C. for 0.5 to 1 hour, then oil quench, and then keep the temperature at 500° C. to 600° C. for 1 to 4 hours and air cool and temper for 2 or 3 times.

5. The method for preparing a high temperature resistant and high fatigue performance bearing steel according to claim 3, characterized in that: In step 1: a vacuum induction furnace + a vacuum consumable furnace is used to melt the master alloy, and the oxygen content of the master alloy is ≤0.0007%, the nitrogen content is ≤0.002%, and H: <0.0001%; ​​a high-purity master alloy casting rod with low oxygen content and high cleanliness is obtained.

6. The method for preparing a high temperature resistant and high fatigue performance bearing steel according to claim 3, characterized in that: In step 2: the oxygen content of the metal powder of high-purity alloy steel is ≤0.025%, the nitrogen content is ≤0.01%, and H: <0.0001%, so as to obtain alloy steel powder with fine particle size and high cleanliness.

7. The method for preparing a high temperature resistant and high fatigue performance bearing steel according to claim 3, characterized in that: In step 2: the alloy steel powder is packaged in a cylindrical package.

Images