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

Abstract

The application relates to a high-temperature-resistant and high-fatigue-performance bearing steel and a preparation method thereof. The bearing steel has the following chemical composition ranges in percentage by weight: 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%, S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%, and the balance of Fe. The 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 more than 65HRC, the high-temperature hardness at 600 DEG C is greater than 58HRC, and under the guarantee of scientific preparation methods and heat treatment processes, the novel powder metallurgy high-temperature bearing steel has higher strength, good strength and toughness, and good high-temperature resistance and fatigue performance.

Description

TECHNICAL FIELD

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

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

[0003] In addition, high-temperature-resistant bearing materials generally contain high contents of alloying elements such as C, Mo, W, V, etc., which are easy to form large particles and net-shaped eutectic carbides. Traditional ingot casting and forging smelting leads to composition segregation and non-uniform organization, which is difficult to eliminate by subsequent forging and heat treatment. Large particles of carbides and composition segregation will seriously affect the fatigue life of the material. Powder metallurgy technology can significantly improve the composition segregation, organization uniformity and eliminate large particles and net-shaped carbides during 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 view of the above, the present application provides a high-temperature-resistant bearing steel with high temperature resistance (≥600℃), low oxygen content, high cleanliness and powder metallurgy, and a preparation method thereof, which is the research motivation of the present application. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a high-temperature-resistant bearing steel with high temperature resistance (≥600℃), low oxygen content, high cleanliness and 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 application has the technical scheme that:

[0007] A high-temperature-resistant and high-fatigue-performance bearing steel, the chemical composition range of the bearing steel is as follows in terms of percentage by weight: 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] Further, the bearing steel has a hardness of ≥65HRC at room temperature and ≥58HRC at 600°C after quenching and tempering; the bearing steel has a tensile strength of ≥2100MPa and an unnotched impact energy of ≥20J at room temperature after quenching and tempering.

[0009] A method for preparing a bearing steel with high temperature resistance and high fatigue performance, comprising the following steps:

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

[0011] Step two: high-purity alloy powder is prepared by a vacuum gas atomization method, the master alloy is smelted under a vacuum degree of 1×10 -3 Pa, high-purity argon is used for atomization, and the powder is screened to obtain high-purity alloy steel metal powder with a particle size of 0-150μm; the alloy steel powder is packaged in a capsule, high-temperature vacuum degassing is performed at 450°C and 1×10 -3 Pa for 16-20h, then the capsule is sealed by brazing to ensure no welding leakage and air leakage; the capsule is placed in a hot isostatic pressing machine, the hot isostatic pressing process is to heat the capsule in the furnace at 1080-1200°C and a pressure of 110-150MPa for 1-5h, then control the temperature at a rate of <40°C / h to cool to below 500°C, and then air cool to obtain a dense hot isostatic pressing sintered blank;

[0012] Step three: the sintered blank is removed from the capsule, heated to 1200°C and held for 2h, and then deformed by one or any combination of a forging hammer, a press and a rolling mill to obtain a new high-temperature powder bearing steel forging material with a compression ratio of 3-10; the carbonides and the matrix structure are refined and homogenized;

[0013] Step four: the alloy steel is annealed after forging, the annealing process is to heat at 840-900°C for 1-4h, then control the temperature at a rate of <20°C / h to cool to 550°C, and then air cool; the hardness after annealing is ≤340HBW; then the surface is polished to obtain a powder high-temperature bearing steel bar; 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] Further, the heat treatment process of the bearing steel is oil quenching after holding at 1150°C-1220°C for 0.5-1h, and then air cooling and tempering at 500-600°C for 1-4h for 2 or 3 times.

[0015] Further, in step one: the mother alloy is smelted by vacuum induction furnace + vacuum consumable furnace method, the oxygen content of the prepared mother alloy is ≤0.0007%, the nitrogen content is ≤0.002%, and H is <0.0001%; a high-purity mother alloy cast rod with low oxygen content and high cleanliness is obtained.

[0016] Further, in step two: the oxygen content of the high-purity alloy steel metal powder is ≤0.025%, the nitrogen content is ≤0.01%, and H is <0.0001%; an alloy steel powder with fine particle size and high cleanliness is obtained.

[0017] Further, in step two: the alloy steel powder is packaged by a cylindrical sleeve.

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

[0019] C: main strengthening element, produces interstitial solid solution strengthening, obtains high hardness martensite, and forms carbides with Cr, W, Mo, and V alloying elements, including the dissolution, precipitation, aggregation, and transformation of carbides. The precipitation process mainly occurs during solidification and tempering, respectively precipitating primary carbides and secondary carbides. Generally, 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 and excessive carbides, increase the non-uniformity of carbides and hot isostatic pressing solidification sintering, which is not conducive to the densification of the hot isostatic pressing blank and the wear resistance, fatigue performance, etc. of the finished steel. Low C content will result in insufficient carbide quantity, which cannot achieve the expected strengthening effect and reduce the high-temperature hardness and fatigue performance of the 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 high-temperature bearing steel is about 4wt%, which can effectively improve the wear resistance and hardenability of the steel. Cr exists in M6C and MC carbides in high-carbon high-temperature bearing steel, and a large number of M 23 C6 carbides are formed during spheroidizing annealing process, and these carbides are almost completely dissolved in austenite during quenching heating process, thereby enhancing the alloying of austenite and improving the hardenability of the steel. In addition, a Cr content of 4wt% can also enhance the oxidation resistance, corrosion resistance, and decarburization resistance of the steel, so the Cr content is controlled at 3.0% to 5.0%.

[0021] Si: Silicon added to high carbon high temperature bearing steel will inhibit the precipitation and growth of sintered high speed steel carbide, improve the distribution and morphology of carbide, and obtain dispersed distribution of carbide organization. At the same time, it can improve the sintering density of high speed steel, reduce the content of austenite in matrix, increase the content of martensite, and improve the hardness. But if the content of Si is too high, the plasticity and toughness of the steel will be significantly reduced. The content of Si is controlled at 0.2% to 1.0%.

[0022] Mn: Strong increase in hardenability element, improve the uniformity and consistency of quenching organization. But too high will increase the content of residual austenite, reduce the strength of steel. The content of Mn is controlled at 0.1% to 1.0%.

[0023] Mo: Mo is the most important alloying element to improve the strength and hot hardness of high temperature bearing steel. It has solid solution strengthening effect when melting in the matrix. Its as-cast eutectic carbide is different from the fishbone-shaped M6C type carbide of high tungsten, but it is thin lamellar, which can decompose and break easily during heat preservation or subsequent hot deformation, so the hot plasticity and toughness of high molybdenum steel are higher than those of high tungsten steel; it can greatly improve the strength and hardness of steel, and also improve the stability of carbide at high temperature. The content of Mo is controlled at 9.0% to 12.0%.

[0024] W in high speed steel can form (W, Fe) 23 C6 and (W, Fe)6C are two special carbides with high hardness and high wear resistance, which are one of the most important hard phases to improve the high temperature hardness and wear resistance of high temperature steel. The fine tungsten carbide particles are mostly distributed at the grain boundaries, which can 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 very high hardness at a temperature of 600°C, that is, the high speed steel has red hardness. When W is dissolved in the high speed steel matrix, it can effectively improve the tempering stability of the steel. The content of W 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 carbide during tempering. In addition, together with Mo and Nb, it can form a complex carbide with high thermal stability, thereby improving the hardness, wear resistance, red hardness and cutting performance of high temperature steel. When the content of V is less than 1%, the red hardness and wear resistance of high speed steel are also low due to the low content of V, and the secondary hardening effect is not good. When the content of V is higher than 3%, the grindability is poor, resulting in high cost of grinding process in subsequent processing. The content of V is controlled at 1.50% to 2.50%.

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

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

[0028] The high-temperature-resistant and high-fatigue-performance powder high-temperature bearing steel of the present application has a room-temperature hardness of more than 65HRC and a high-temperature hardness of more than 58HRC at 600℃. Under the guarantee of scientific preparation methods and heat treatment processes, the new powder metallurgy high-temperature bearing steel has higher strength, good strength and toughness, and good high-temperature resistance and fatigue performance. Compared with the prior art, the service temperature and fatigue performance of the bearing steel are improved, and the bearing steel has good popularization and application value. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is the microstructure of the high-temperature-resistant and high-fatigue-performance bearing steel of Example 1 after annealing.

[0030] Figure 2 The figure is the microstructure of the high-temperature-resistant and high-fatigue-performance bearing steel of Example 1 after quenching and tempering. DETAILED DESCRIPTION

[0031] The present application will be described in detail below with reference to the embodiments and the accompanying drawings, and it should be pointed out that the described embodiments are only intended to facilitate the understanding of the present application and do not limit the present application in any way.

[0032] Example 1

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

[0034] Step one: according to the proportioning of each element of the alloy, high-purity alloy raw materials are used for proportioning, and the raw material proportioning is 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%, and the balance is Fe. In the present embodiment, a vacuum induction method is used to melt the master alloy, and a low-oxygen-content and high-purity master alloy ingot is obtained by pouring the ingot. A 50-kilogram vacuum induction furnace is used to prepare a 50-kilogram alloy steel ingot, and the steel ingot is peeled and the riser is removed to obtain a high-purity master alloy bar.

[0035] Step two: high-purity alloy powder is prepared by a vacuum gas atomization (VIGA) method, and the vacuum degree is 1×10 - 3The melting master alloy is smelted under a Pa environment, high-purity argon (purity 99.99%) is used for atomization, and the powder is screened to obtain high-purity alloy steel metal powder of 0-150 μm, then the powder is packaged into a cylindrical iron jacket, and the high-temperature vacuum degassing is performed under a Pa high vacuum for 20 h, then the jacket is sealed by brazing to ensure no leakage and air leakage, and then the hot isostatic pressing machine is used, the jacket is heated in the furnace at 1090 °C and 120 MPa pressure for 4 h, then the temperature is controlled to cool at a rate of <40 °C / h to 500 °C or below, and then air cooling is performed to obtain a dense hot isostatic pressing sintered blank. - 3 The high-temperature vacuum degassing is performed under a Pa high vacuum for 20 h, then the jacket is sealed by brazing to ensure no leakage and air leakage, and then the hot isostatic pressing machine is used, the jacket is heated in the furnace at 1090 °C and 120 MPa pressure for 4 h, then the temperature is controlled to cool at a rate of <40 °C / h to 500 °C or below, and then air cooling is performed to obtain a dense hot isostatic pressing sintered blank.

[0036] Step three: the sintered blank is removed from the jacket, heated to 1200 °C for 2 h, and then deformed by one or any combination of a forging hammer, a press, and a rolling mill to obtain a new high-temperature powder bearing steel forging material with a compression ratio of 5; the carbonides and the matrix structure are refined and homogenized.

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

[0038] Then, chemical analysis, structure, and hardness samples are taken from the bar, quenched + tempered, and the room temperature hardness and high-temperature hardness performance are measured. The chemical composition results are shown in Table 1.

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

[0040]

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

[0042] Quenching: 1190 °C, holding for 30 min, oil cooling;

[0043] Tempering: 560 °C, holding for 1 h, air cooling. Tempering 2 times.

[0044] The annealing structure and quenching and tempering structure of the test steel are as follows: Figure 1 and Figure 2The microstructure is even and no obvious large carbide particle is found after annealing. The size of carbide particle is less than 3 microns. The even and fine microstructure ensures the stability of performance and high fatigue performance. After quenching and tempering, part of carbide is dissolved, and tempered martensite and tempering precipitated carbide are obtained after quenching and tempering.

[0045] The mechanical property results are shown in Table 2 and Table 3. The obtained 1# high temperature bearing steel has a hardness of ≥65HRC at room temperature and ≥58HRC at 600℃ after quenching and tempering. The high hardness at room temperature and high temperature can ensure its high temperature resistance at 600℃ and high fatigue performance. The obtained high temperature bearing steel has a tensile strength of ≥2100MPa at room temperature and an impact energy of ≥20J without notch after quenching and tempering. Compared with super high carbon steel, it has good strength and toughness.

[0046] Table 2 Rockwell hardness at room temperature and high temperature, 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℃, holding for 30min, oil cooling;

[0052] Tempering: 550℃, holding for 2 hours, air cooling. Tempering twice.

[0053] The mechanical property results are shown in Table 4 and Table 5. The obtained 2# high temperature bearing steel has a hardness of ≥65HRC at room temperature and ≥57HRC at 600℃ after quenching and tempering.

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

[0055]

[0056] Example 2

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

[0058] Step one: according to the proportion of each element of the alloy, high purity alloy raw materials are used for batching, 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, the master alloy is melted by a vacuum induction furnace + vacuum consumable furnace (double vacuum) method, the oxygen content of the prepared master alloy is ≤0.0007%, the nitrogen content is ≤0.002%, and H: <0.0001%; a high-purity master alloy ingot with low oxygen content and high cleanliness is obtained.

[0059] Step two: the master alloy rod is first vacuum gas atomized to powder: the master alloy is melted under a vacuum degree of 1x10 -3 Pa environment, and high-purity argon (purity 99.99%) is used for atomization. The prepared alloy steel powder is sieved to obtain alloy powder with a particle size of 0~53 μm. The alloy steel powder is packaged in a cylindrical sheath, and is treated by high-temperature vacuum degassing for 17 h under a high vacuum of 450°C and 1x10 -3 Pa, and then is sealed by sheath brazing to ensure no leakage and air leakage; the sheath is placed in a hot isostatic pressing machine, and the hot isostatic pressing process is as follows: the sheath is heated in the furnace at 1180°C and 140 MPa for 2 h, and then is cooled to below 500°C at a temperature control rate of <40°C / h, and is air-cooled to obtain a dense hot isostatic pressing sintered blank.

[0060] Step three: the sintered blank is removed from the sheath, heated to 1200°C for 2 h, and then is subjected to open die forging or hot rolling by using one or any combination of deformation equipment such as a forging hammer, a press, and a rolling mill, and the forging temperature range is 1180~900°C; a new type of high-temperature powder bearing steel forging material with a compression ratio of 8 is obtained; and the fine and uniformization of carbides and matrix organization is realized.

[0061] Step four: the alloy steel is annealed after forging, and the annealing process of the inventive steel is as follows: the forged material is annealed. Another annealing process is as follows: heating at 840~900°C for 1~4 h, and then cooling to 550°C at a temperature control rate of <20°C / h, and air cooling; the hardness after annealing is ≤340 HBW; and then surface finishing is performed to obtain a powder high-temperature bearing steel rod.

[0062] Then, chemical analysis, organization, and hardness samples are taken from the rod, and the room temperature hardness and high-temperature hardness performance are measured after quenching + tempering. The chemical composition results are shown in Table 5.

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

[0064]

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

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

[0067] Tempering: 560℃, holding for 1h, air cooling. Tempering twice.

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

[0069] Table 6: Rockwell hardness at room temperature and high temperature, HRC

[0070]

[0071] Table 7: Mechanical properties at room temperature

[0072]

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

[0074] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the application, and are not intended to limit the scope of protection of the application. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the application.

Claims

1. A high-temperature and high-fatigue performance bearing steel, characterized in that, The chemical composition range of the bearing steel is as follows in terms of percentage by weight: 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%, S: <0.01%, P: <0.01%, O: <0.025%, N: <0.01%, H: <0.0001%, and the balance being Fe; The preparation method of the bearing steel with high temperature resistance and high fatigue performance comprises the following steps: Step one: the bearing steel master alloy is melted by a vacuum induction method or a vacuum induction furnace + vacuum consumable furnace method, and a high-purity master alloy ingot with low oxygen content and high cleanliness is obtained by pouring and casting; the ingot is peeled and the riser is cut off to obtain a high-cleanliness master alloy; Step 2: High-purity alloy powder is prepared by vacuum atomization powder preparation method at a vacuum degree of 1×10⁻⁶. -3 The master alloy was smelted under Pa conditions, and atomized with high-purity argon gas. After sieving, the powder was obtained as high-purity alloy steel powder with a particle size of 0-150 μm. The alloy steel powder was then encapsulated and subjected to 450℃ and 1×10⁻⁶ ppm for further processing. -3 The blank is subjected to high-temperature vacuum degassing for 16-20 hours under high vacuum, followed by brazing and sealing to ensure no weld or gas leakage. It is then placed in a hot isostatic press. The hot isostatic pressing process involves heating the blank in the furnace at 1080-1200℃ and 110-150MPa pressure for 1-5 hours, followed by controlled cooling at a rate of <40℃ / h to below 500℃ and air cooling to obtain a dense hot isostatic pressed sintered blank. Step three: the sintered blank is heated to 1200 DEG C for 2 hours after removing the package, and then is subjected to open die forging or hot rolling by using one or any combination of a forging hammer, a press or a rolling mill, the forging temperature ranges from 1180 DEG C to 900 DEG C, a high-temperature powder bearing steel forging material with a compression ratio of 3-10 is obtained, and the carbide and matrix structure are refined and homogenized; Step four: the alloy steel is annealed after forging, the annealing process is heating at 840-900 DEG C for 1-4 hours, then controlled cooling at a rate of <20 DEG C / h to 550 DEG C, and air cooling; the hardness after annealing is ≤340 HBW; then surface finishing is performed to obtain a powder high-temperature bearing steel bar; 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%; The heat treatment process of the bearing steel is oil quenching after heating at 1150 DEG C-1220 DEG C for 0.5-1 hour and then air cooling tempering at 500-600 DEG C for 1-4 hours for 2 or 3 times.

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

3. The high-temperature and high-fatigue property bearing steel according to claim 1, characterized in that: In step one: the master alloy is melted by a vacuum induction furnace + vacuum consumable furnace method, the oxygen content of the prepared master alloy is ≤0.0007%, the nitrogen content is ≤0.002%, and H: <0.0001%; a high-purity master alloy ingot with low oxygen content and high cleanliness is obtained.

4. The high-temperature and high-fatigue property bearing steel according to claim 1, characterized in that: In step two: the metal powder of the high-purity alloy steel has an oxygen content of ≤0.025%, a nitrogen content of ≤0.01%, and H: <0.0001%, and a fine particle size and high cleanliness of the alloy steel powder are obtained.

5. The high-temperature and high-fatigue property bearing steel according to claim 1, characterized in that: In step two: the alloy steel powder is packaged by a cylindrical package.

Images