A kind of aviation bearing and its production method

Abstract

The present invention is applicable to the field of aerospace bearing technology, and provides an aerospace bearing and a production method thereof, wherein the method comprises the following steps: smelting high alloy steel G13Cr4Mo4Ni4V into bearing steel ingots through an electric furnace process and an electroslag remelting process; forging the smelted bearing steel ingots; machining the processed bearing steel ingots, and then subjecting them to surface carburizing heat treatment; subjecting them to high temperature heat treatment using a multi-stage heat treatment system after the surface carburizing heat treatment; and further subjecting them to tissue heat treatment after the high temperature heat treatment to obtain an aerospace bearing. The bearings produced by the present invention not only have high wear resistance and high surface contact fatigue life, but also have high toughness and significantly improved service life. The bearings produced by the present invention have both good service life and use effect, while also taking into account the production and manufacturing costs, and meet market demand.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace bearings, and in particular relates to an aerospace bearing and a production method thereof. Background Art

[0002] Bearings are very important parts in mechanical equipment, and their service performance and service life have a great impact on the operation of the equipment. At the same time, bearings, as commonly used mechanical parts, are widely used in various fields of the national economy, such as aerospace engineering, transportation engineering, power industry, energy industry, etc. As my country's aerospace industry is in urgent need of development, high requirements are placed on aerospace bearing manufacturing technology.

[0003] At present, the manufacturing and use materials of bearings at home and abroad are mainly based on three materials: GCr15, 8Cr4Mo4V and G13Cr4Mo4Ni4V. Among them, the most excellent material is G13Cr4Mo4Ni4V steel, which has an operating temperature of about 350℃ and a surface hardness of 850HV after carburizing, and has good comprehensive performance. Summary of the invention

[0004] In view of the above problems, on the one hand, the present invention provides a method for producing an aviation bearing, the method comprising:

[0005] The high alloy steel G13Cr4Mo4Ni4V is smelted into bearing steel ingots through electric furnace process and electroslag remelting process;

[0006] The smelted bearing steel ingots are forged;

[0007] The processed bearing steel ingots are machined and then subjected to surface carburizing heat treatment;

[0008] After the surface carburizing heat treatment, a multi-stage heat treatment system is used for high temperature heat treatment;

[0009] After the high temperature heat treatment, further tissue heat treatment is performed to obtain an aviation bearing.

[0010] Furthermore, the forging temperature of the bearing steel ingot is 1100-1200° C., and the forging is performed by a three-upsetting and three-drawing method.

[0011] Furthermore, the forging ratio of the forging treatment is ≥2, the initial forging temperature is 1100-1140°C, and the final forging temperature is ≥860°C.

[0012] Furthermore, the surface carburizing heat treatment first cleans the surface of the machined bearing steel ingot, and then places the bearing steel ingot into a vacuum low-pressure carburizing furnace for carburizing treatment; wherein the carburizing temperature is 900-930°C, the number of carburizing pulses is 18-20, the carburizing time is ≤18h, and the carburizing ratio is 1:24.

[0013] Furthermore, the high temperature heat treatment time is ≤15min;

[0014] Furthermore, in the multi-stage heat treatment, the first stage heat treatment heats the bearing steel ingot to 560-600° C. and keeps the temperature for 5-5.5 min;

[0015] The second stage heat treatment raises the temperature of the bearing steel ingot to 800-845°C and keeps it at this temperature for 3-3.5 minutes;

[0016] The third stage heat treatment raises the temperature of the bearing steel ingot to 890-930°C and keeps it at this temperature for 3-3.5 minutes;

[0017] The fourth stage heat treatment raises the temperature of the bearing steel ingot to 950-1000°C and keeps it at this temperature for 3-3.5 minutes.

[0018] Further, the tissue heat treatment comprises:

[0019] subjecting the bearing steel ingot after high temperature heat treatment to a molten salt bath;

[0020] The bearing steel ingot is tempered after the molten salt bath;

[0021] After tempering, the bearing steel ingot is cold treated.

[0022] Furthermore, the temperature of the molten salt bath is 520-540° C., and the time is 10-15 minutes.

[0023] Furthermore, the tempering treatment is performed at a temperature of 530-535° C. and is performed 3-4 times.

[0024] Furthermore, the cold treatment temperature is -70°C to -80°C, and the treatment time is 1.5 to 2.0 hours.

[0025] On the other hand, the present invention also provides an aviation bearing, wherein the bearing steel is produced by the above production method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides an aviation bearing and a production method thereof, which combines production cost and service life, selects G13Cr4Mo4Ni4V as the base material, and makes appropriate composition adjustments and production process improvements thereto, and sets a reasonable heat treatment system according to the phase change point of the material, so that the product achieves good performance. The bearings produced by the present invention not only have good service life and use effect, but also take into account the production and manufacturing costs, thus meeting market demand. The aerospace bearings produced according to the present invention have a surface hardness ≥850HV and an internal impact toughness of 30-35J / cm 2It not only has high wear resistance and high surface contact fatigue life, but also has high toughness, which significantly improves the service life.

[0028] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 The following is a flow chart showing the preparation of an aviation bearing and a production method thereof according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In order to improve the comprehensive performance of bearings produced under the existing technology, such as strength, hardness and wear resistance, this paper provides a method for producing aviation bearings, which can improve the wear resistance, hardness, strength and toughness of aerospace bearings. Figure 1 As shown, the method includes:

[0033] The high alloy steel G13Cr4Mo4Ni4V is smelted into bearing steel ingots through electric furnace process and electroslag remelting process; the smelted bearing steel ingots are forged; the processed bearing steel ingots are machined and then subjected to surface carburizing heat treatment; after the surface carburizing heat treatment, a multi-stage heat treatment system is used to perform high temperature heat treatment; after the high temperature heat treatment, a tissue heat treatment is further performed to finally obtain an aviation bearing.

[0034] It should be noted that the high alloy steel G13Cr4Mo4Ni4V is composed of the following chemical components in mass percentage, wherein the carbon content is 0.14% to 0.17%, the silicon content is 0.15% to 0.20%, the manganese content is 0.15% to 0.20%, the phosphorus content is ≤0.010%, the sulfur content is ≤0.005%, the chromium content is 4.00% to 4.10%, the molybdenum content is 4.20% to 4.30%, the nickel content is 3.40% to 3.50%, the vanadium content is 1.00-1.20%, and the balance is iron and impurities.

[0035] It should be noted that the forging temperature of the bearing steel ingot is 1100-1200° C., and the forging is performed by a three-upsetting and three-drawing method.

[0036] Furthermore, the forging ratio of the forging treatment is ≥2, the initial forging temperature is 1100-1140°C, and the final forging temperature is ≥860°C. If the temperature of the bearing steel ingot is lower than 860°C, it needs to be promptly sent to the furnace for heating and temperature raising. Since the grain size of the bearing steel ingot will increase through a series of subsequent heat treatment processes, in order to ensure the toughness of the bearing steel ingot, the grain size needs to be strictly controlled during the forging process. By controlling the grain size of the bearing steel ingot during the forging process, the bearing steel ingot can have a fine grain structure. Furthermore, in order to prevent cracks in the steel ingot, it should be covered with an insulation cover after forging, slow cooling treatment should be carried out, and annealing should be carried out in time.

[0037] It should be noted that, according to the requirements of the drawings, the bearing steel ingot is processed into a preset size, and the surface of the processed bearing steel ingot is cleaned, and then the bearing steel ingot is placed in a vacuum low-pressure carburizing furnace for carburizing treatment; wherein, the carburizing temperature is 900-930°C, the number of carburizing pulses is 18-20, the carburizing time is ≤18h, and the expansion ratio is 1:24. After surface carburizing heat treatment, the surface hardness of the bearing steel ingot can reach 850HV, and the carburized layer thickness is 1.5mm-2.0mm.

[0038] It should be noted that the bearing steel ingot after surface carburizing heat treatment is further subjected to high temperature heat treatment.

[0039] Among them, in order to avoid the growth of austenite grains, the high temperature heat treatment time is ≤15min.

[0040] It should be noted that the multi-stage heat treatment is specifically as follows: the first stage heat treatment heats the bearing steel ingot to 560-600°C and keeps the temperature for 5-5.5 minutes;

[0041] The second stage heat treatment raises the temperature of the bearing steel ingot to 800-845°C and keeps it at this temperature for 3-3.5 minutes;

[0042] The third stage heat treatment raises the temperature of the bearing steel ingot to 890-930°C and keeps it at this temperature for 3-3.5 minutes;

[0043] The fourth stage heat treatment raises the temperature of the bearing steel ingot to 950-1000°C and keeps it at this temperature for 3-3.5 minutes.

[0044] It should be noted that in order to improve the mechanical properties of the bearing, the bearing steel ingot is subjected to a tissue heat treatment to regulate its structure, and the tissue heat treatment includes:

[0045] subjecting the bearing steel ingot after high temperature heat treatment to a molten salt bath;

[0046] The bearing steel ingot is tempered after the molten salt bath;

[0047] After tempering, the bearing steel ingot is cold treated.

[0048] It should be noted that the temperature of the molten salt bath is 520-540° C. and the time is 10-15 minutes.

[0049] It should be noted that the temperature of the tempering treatment is 530-535° C. and the number of times is 3-4 times.

[0050] It should be noted that cold treatment is required after each tempering, the cold treatment temperature is -70°C to -80°C, and the treatment time is 1.5 to 2.0 hours. After tempering, the bearing steel ingot structure basically does not contain martensite structure, and its main components are tempered troostite and a small amount of bainite structure.

[0051] It should be noted that the present invention relates to an aviation bearing, which is produced based on the above-mentioned production method.

[0052] It should also be noted that the aviation bearing produced according to the method of the present invention has a surface hardness greater than 850HV and an internal impact toughness of 30-35J / cm 2 It not only has high wear resistance and high surface contact fatigue life, but also has high toughness, and its service life is significantly improved.

[0053] Example 1

[0054] The high alloy steel G13Cr4Mo4Ni4V involved in Example 1 is composed of the following chemical components by mass percentage, wherein the carbon content is 0.16%, the silicon content is 0.18%, the manganese content is 0.18%, the phosphorus content is 0.010%, the sulfur content is 0.004%, the chromium content is 4.08%, the molybdenum content is 4.25%, the nickel content is 3.45%, the vanadium content is 1.15%, and the balance is iron and impurities. The high alloy steel G13Cr4Mo4Ni4V is smelted by an electric furnace process and an electroslag remelting process according to the above composition.

[0055] The smelted bearing steel ingot is forged. First, the temperature is raised to 1180℃, and the three-upsetting and three-drawing method is used for forging. The forging ratio is 2.2, the initial forging temperature is 1125℃, and the final forging temperature is ≥875℃. After forging, it is covered with a heat preservation cover for slow cooling treatment and annealed in time at a temperature of 645℃, and cooled in the furnace.

[0056] The processed bearing steel ingots are machined into preset sizes according to the requirements of the drawings, and then subjected to surface carburizing heat treatment. After the surface of the bearing steel ingot is cleaned, it is placed in a vacuum low-pressure carburizing furnace for carburizing treatment. The carburizing temperature is 930°C. After the bearing steel ingot is completely austenitized, surface carburizing treatment begins. To prevent coarse grain structure, the number of carburizing pulses is 22, the total carburizing time is 15h, and the expansion and carburizing ratio is 1:23. After carburizing treatment, the surface hardness of the bearing steel ingot is 850HV and the thickness of the carburized layer is 1.5mm.

[0057] After the surface carburizing heat treatment, a multi-stage heat treatment system is adopted to perform high-temperature heat treatment on the bearing steel ingot. In the multi-stage heat treatment system, the first stage heat treatment heats the bearing steel ingot to 585°C and keeps it warm for 5 minutes, the second stage heat treatment heats the bearing steel ingot to 835°C and keeps it warm for 3 minutes, the third stage heat treatment heats the bearing steel ingot to 915°C and keeps it warm for 3 minutes, and the fourth stage heat treatment heats the bearing steel ingot to 985°C and keeps it warm for 3 minutes.

[0058] After high-temperature heat treatment, the bearing steel ingot is further subjected to structural heat treatment. In order to improve the mechanical properties of the bearing, a 535°C molten salt bath is used for 13 minutes, and then 3 to 4 tempering treatments are carried out at 530°C. Tempering treatment is required after each tempering treatment. After tempering treatment, the bearing steel ingot structure basically does not contain martensite structure, and its main structure is tempered troostite and a small amount of bainite structure.

[0059] The aviation bearing produced according to the present invention has a surface hardness of ≥850HV and an internal impact toughness of 30-35J / cm 2 The aviation bearing not only has high wear resistance and high surface contact fatigue life, but also has high toughness, and its service life is significantly improved.

[0060] Example 2

[0061] The high alloy steel G13Cr4Mo4Ni4V involved in Example 2 is composed of the following chemical components by mass percentage, wherein the carbon content is 0.16%, the silicon content is 0.18%, the phosphorus content is 0.010%, the sulfur content is 0.004%, the chromium content is 4.08%, the molybdenum content is 4.25%, the nickel content is 3.45%, the vanadium content is 1.15%, and the balance is iron and impurities. The high alloy steel G13Cr4Mo4Ni4V is smelted by an electric furnace process and an electroslag remelting process according to the above composition.

[0062] The smelted bearing steel ingot is forged. First, the temperature is raised to 1146℃, and the three-upsetting and three-drawing method is used for forging. The forging ratio is 2.3, the initial forging temperature is 1120℃, and the final forging temperature is 875℃. After forging, it is covered with a heat preservation cover for slow cooling treatment and annealed in time at a temperature of 655℃, and cooled in the furnace.

[0063] The processed bearing steel ingots are machined into preset sizes according to the requirements of the drawings, and then subjected to surface carburizing heat treatment. After the surface of the bearing steel ingot is cleaned, it is placed in a vacuum low-pressure carburizing furnace for carburizing treatment. The carburizing temperature is 925°C. After the bearing steel ingot is completely austenitized, surface carburizing treatment is started. To prevent coarse grain structure, the number of carburizing pulses is 16, the total carburizing time is 17h, and the expansion and carburizing ratio is 1:23. After carburizing treatment, the surface hardness of the bearing steel ingot is 862HV and the thickness of the carburized layer is 1.4mm.

[0064] After the surface carburizing heat treatment, the bearing steel ingot is subjected to high-temperature heat treatment by a multi-stage heat treatment system. In the multi-stage heat treatment system, the first stage heat treatment heats the bearing steel ingot to 575°C and keeps it warm for 5 minutes, the second stage heat treatment heats the bearing steel ingot to 820°C and keeps it warm for 3 minutes, the third stage heat treatment heats the bearing steel ingot to 920°C and keeps it warm for 3 minutes, and the fourth stage heat treatment heats the bearing steel ingot to 985°C and keeps it warm for 3 minutes.

[0065] After high-temperature heat treatment, the bearing steel ingot is further subjected to structural heat treatment. In order to improve the mechanical properties of the bearing, it is subjected to 530°C molten salt bath for 13 minutes and then tempered at 525°C for 4 times. Tempering treatment is required after each tempering treatment. After tempering treatment, the bearing steel ingot structure basically does not contain martensite structure, and its main structure is tempered troostite and a small amount of bainite structure.

[0066] The aviation bearing produced according to the present invention has a surface hardness of ≥850HV and an internal impact toughness of 30-35J / cm 2 The aviation bearing not only has high wear resistance and high surface contact fatigue life, but also has high toughness, and its service life is significantly improved.

[0067] Example 3

[0068] The high alloy steel G13Cr4Mo4Ni4V involved in Example 3 is composed of the following chemical components by mass percentage, wherein the carbon content is 0.16%, the silicon content is 0.18%, the manganese content is 0.17%, the phosphorus content is 0.009%, the sulfur content is 0.005%, the chromium content is 4.08%, the molybdenum content is 4.25%, the nickel content is 3.45%, and the balance is iron and impurities. The high alloy steel G13Cr4Mo4Ni4V is smelted by an electric furnace process and an electroslag remelting process according to the above composition.

[0069] The smelted bearing steel ingot is forged. First, the temperature is raised to 1100℃, and the three-upsetting and three-drawing method is used for forging. The forging ratio is 2.5, the initial forging temperature is 1135℃, and the final forging temperature is 876℃. After forging, it is covered with a heat preservation cover for slow cooling treatment and annealed in time at a temperature of 665℃, and cooled in the furnace.

[0070] The processed bearing steel ingots are machined into preset sizes according to the requirements of the drawings, and then subjected to surface carburizing heat treatment. After the surface of the bearing steel ingot is cleaned, it is placed in a vacuum low-pressure carburizing furnace for carburizing treatment. The carburizing temperature is 920°C. After the bearing steel ingot is completely austenitized, surface carburizing treatment begins. To prevent coarse grain structure, the number of carburizing pulses is 18, the total carburizing time is 14h, and the expansion and carburizing ratio is 1:22. After carburizing treatment, the surface hardness of the bearing steel ingot is 860HV and the thickness of the carburized layer is 1.0mm.

[0071] After the surface carburizing heat treatment, a multi-stage heat treatment system is adopted to perform high-temperature heat treatment on the bearing steel ingot. In the multi-stage heat treatment system, the first stage heat treatment heats the bearing steel ingot to 580°C and keeps it warm for 5 minutes, the second stage heat treatment heats the bearing steel ingot to 835°C and keeps it warm for 3 minutes, the third stage heat treatment heats the bearing steel ingot to 925°C and keeps it warm for 3 minutes, and the fourth stage heat treatment heats the bearing steel ingot to 970°C and keeps it warm for 3 minutes.

[0072] After high-temperature heat treatment, the bearing steel ingot is further subjected to structural heat treatment. In order to improve the mechanical properties of the bearing, a 535°C molten salt bath is used for 14 minutes, and then 3 to 4 tempering treatments are carried out at 525°C. Tempering treatment is required after each tempering treatment. After tempering treatment, the bearing steel ingot structure basically does not contain martensite structure, and its main structure is tempered troostite and a small amount of bainite structure.

[0073] The aviation bearing produced according to the present invention has a surface hardness of ≥850HV and an internal impact toughness of 30-35J / cm 2 The aviation bearing not only has high wear resistance and high surface contact fatigue life, but also has high toughness, and its service life is significantly improved.

[0074] The invention provides a suitable forging process, adjusts the heat treatment process, and adopts surface carburization and other means to make the bearing structure into tempered troostite and a small amount of bainite structure, thereby obtaining an aviation bearing with high surface hardness, high wear resistance and high core toughness.

[0075] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing an aviation bearing, characterized in that: The method comprises: The high alloy steel G13Cr4Mo4Ni4V is smelted into a bearing steel ingot through an electric furnace process and an electroslag remelting process; the high alloy steel G13Cr4Mo4Ni4V is composed of the following chemical components in mass percentage: carbon content 0.14% to 0.17%, silicon content 0.15% to 0.20%, manganese content 0.15% to 0.20%, phosphorus content ≤0.010%, sulfur content ≤0.005%, chromium content 4.00% to 4.10%, molybdenum content 4.20% to 4.30%, nickel content 3.40% to 3.50%, vanadium content 1.00% to 1.20%, and the balance is iron and impurities; The smelted bearing steel ingot is forged; after forging, it is covered with a heat preservation cover, subjected to slow cooling treatment, annealed, and cooled in a furnace; The processed bearing steel ingot is subjected to mechanical processing, and then subjected to surface carburizing heat treatment; the surface carburizing heat treatment first cleans the surface of the mechanically processed bearing steel ingot, and then places the bearing steel ingot into a vacuum low-pressure carburizing furnace for carburizing treatment, wherein the carburizing temperature is 900-930°C, the number of carburizing pulses is 18-20, the carburizing time is ≤18h, and the expansion ratio is 1:24; After the surface carburizing heat treatment, a multi-stage heat treatment system is used for high-temperature heat treatment; the high-temperature heat treatment time is ≤15min; in the multi-stage heat treatment, the first stage heat treatment heats the bearing steel ingot to 560-600°C and keeps it warm for 5-5.5min; the second stage heat treatment heats the bearing steel ingot to 800-845°C and keeps it warm for 3-3.5min; the third stage heat treatment heats the bearing steel ingot to 890-930°C and keeps it warm for 3-3.5min; the fourth stage heat treatment heats the bearing steel ingot to 950-1000°C and keeps it warm for 3-3.5min; After the high-temperature heat treatment, a tissue heat treatment is further performed to obtain an aviation bearing; the tissue heat treatment includes subjecting the bearing steel ingot after the high-temperature heat treatment to a molten salt bath; the temperature of the molten salt bath is 520-540°C, and the time is 10-15 minutes; the bearing steel ingot after the molten salt bath is tempered; after the tempering treatment, the bearing steel ingot is cold-treated; the temperature of the tempering treatment is 530-535°C, and the number of times is 3-4 times; the cold treatment temperature is -70°C--80°C, and the treatment time is 1.5-2.0 hours.

2. The method for producing an aviation bearing according to claim 1, wherein: The forging temperature of bearing steel ingot is 1100~1200℃, and the three-upsetting and three-drawing method is adopted for forging.

3. The method for producing an aviation bearing according to claim 2, wherein: The forging ratio of the forging treatment is ≥2, the initial forging temperature is 1100-1140°C, and the final forging temperature is ≥860°C.

4. An aviation bearing produced based on the production method according to any one of claims 1 to 3.

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