A high-strength bearing and its manufacturing process

Abstract

This invention relates to the field of bearing technology and proposes a high-strength bearing and its manufacturing process. The high-strength bearing is composed of the following components by mass percentage: C 0.13%~0.23%, Mn 0.3%~0.4%, Si 0.27%~0.67%, Mo 0.15%~0.25%, Cr 1.2%~4.2%, Al 0.23%~0.33%, Cu 0.02%~0.06%, Nb 0.1%~0.2%, V 0.06%~0.08%, W 0.1%~0.2%, Sm 0.01%~0.015%, Pr 0.002%~0.005%, Y 0.01%~0.015%, with the balance being Fe and other unavoidable impurities. This technical solution solves the problem of insufficient bearing strength in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, specifically to a high-strength bearing and its manufacturing process. Background Technology

[0002] Bearings are crucial supporting components in mechanical equipment, enabling machines to rotate or move with minimal friction during operation. With the continuous development of the bearing industry, the performance requirements for bearings are becoming increasingly stringent. Bearings are typically made of alloy steel. However, the alloy steel used in traditional bearings not only involves a complex manufacturing process but also suffers from insufficient strength, making it difficult to meet current demands. Therefore, the development of high-strength bearings is vital for industrial development. Summary of the Invention

[0003] This invention proposes a high-strength bearing and its manufacturing process, which solves the problem of insufficient bearing strength in related technologies.

[0004] The technical solution of the present invention is as follows:

[0005] This invention proposes a high-strength bearing composed of the following components by mass percentage: C 0.13%~0.23%, Mn 0.3%~0.4%, Si 0.27%~0.67%, Mo 0.15%~0.25%, Cr 1.2%~4.2%, Al 0.23%~0.33%, Cu 0.02%~0.06%, Nb 0.1%~0.2%, V 0.06%~0.08%, W 0.1%~0.2%, Sm 0.01%~0.015%, Pr 0.002%~0.005%, Y 0.01%~0.015%, with the balance being Fe and other unavoidable impurities.

[0006] As a further technical solution, the high-strength bearing is composed of the following components by mass percentage: C 0.13%~0.23%, Mn 0.3%~0.4%, Si 0.27%~0.67%, Mo 0.15%~0.25%, Cr 1.2%~4.2%, Al 0.23%~0.33%, Cu 0.02%~0.06%, Nb 0.1%~0.2%, V 0.06%~0.08%, W 0.1%~0.2%, Sm 0.01%~0.015%, Pr 0.002%~0.005%, Y 0.01%~0.015%, with the balance being Fe and other unavoidable impurities, and 0.025%≤Pr+Sm+Y≤0.028%.

[0007] In this invention, the mass percentages of Pr, Sm, and Y in the bearing components are precisely defined as 0.025% ≤ Pr + Sm + Y ≤ 0.028%, which enhances the synergistic effect of the three elements and significantly improves the strength of the bearing.

[0008] This invention also proposes a manufacturing process for a high-strength bearing, comprising the following steps:

[0009] S1. Weigh the raw materials according to the mass percentage, melt the raw materials to form an alloy liquid, pour it into a steel ingot, cool it to room temperature, and hot roll the steel ingot to obtain a steel billet;

[0010] S2. The steel billet is rolled, the rolled steel billet is cut into sections, heated and forged to obtain forgings, and the forgings are rolled and expanded to obtain bearing semi-finished products;

[0011] S3. The bearing semi-finished product is subjected to normalizing and carburizing treatment;

[0012] S4. The carburized bearing semi-finished product is subjected to spheroidizing annealing, quenching, and tempering treatment, and then precision grinding to obtain a high-strength bearing.

[0013] As a further technical solution, the hot rolling treatment is carried out at a temperature of 1200~1250℃ for 4~6 hours, followed by air cooling to 600~700℃ and then rapid cooling to room temperature.

[0014] As a further technical solution, the initial rolling temperature is 1000~1200℃, the holding time is 6~10min, the initial rolling temperature is 880~1000℃, the final rolling temperature is 780~820℃, and the temperature is rapidly cooled to 650~680℃ and then air-cooled.

[0015] As a further technical solution, the heating temperature is 800~900℃, and the holding time is 30~60min.

[0016] As a further technical solution, the forging ratio is 1.5~2.0 and the temperature is 850~900℃.

[0017] As a further technical solution, the normalizing treatment temperature is 870~920℃, the holding time is 2~3 hours, and then air cooling is performed.

[0018] As a further technical solution, the carbon potential in the carburizing treatment is 0.85%~1.20%, the temperature is raised to 875~900℃ at a heating rate of 7℃ / min~12℃ / min, and the holding time is 5.5~7.5h.

[0019] As a further technical solution, the carburizing treatment includes a first stage carburizing treatment, a second stage carburizing treatment, and a third stage carburizing treatment.

[0020] As a further technical solution, the carbon potential in the first stage of carburizing treatment is 1.05%~1.20%, the heating temperature is 875~880℃, and the holding time is 3.3~4.3h.

[0021] As a further technical solution, the carbon potential in the second stage of carburizing treatment is 0.95%~1.02%, the heating temperature is 885~890℃, and the holding time is 1.2~2.2h.

[0022] As a further technical solution, the carbon potential in the third stage carburizing treatment is 0.85%~0.92%, the heating temperature is 895~900℃, and the holding time is 1~2h.

[0023] In the bearing manufacturing process of this invention, a three-stage carburizing treatment is selected. The carbon potential in the first stage of carburizing is controlled at 1.05%~1.20%. The higher carbon potential allows a large number of carbon atoms to diffuse rapidly to the surface of the bearing steel and penetrate into the interior, which is beneficial to the second stage of carburizing. In the second stage of carburizing, the carbon potential is 0.95%~1.02%. The diffusion rate of carbon atoms slows down in this stage, which is conducive to a more uniform distribution of carbides. In the third stage of carburizing, the carbon potential is 0.85%~0.92%. This stage makes the carbides more stable and dense, forming a continuous, dense and uniformly distributed carbide layer on the bearing surface. The three-stage carburizing treatment significantly improves the corrosion resistance of the bearing.

[0024] As a further technical solution, the spheroidizing annealing treatment is carried out at a temperature of 750~780℃ for 4~6 hours.

[0025] As a further technical solution, the quenching temperature is 850~870℃, the holding time is 15~20min, and the quenching is done by oil quenching.

[0026] As a further technical solution, the temperature of the quenching oil used in the oil quenching is 65~75℃.

[0027] As a further technical solution, the tempering treatment temperature is 150~200℃ and the time is 2~4h.

[0028] The working principle and beneficial effects of this invention are as follows:

[0029] In this invention, the introduction of elements Pr, Sm, and Y into the bearing increases its strength. Pr refines the grains, providing more uniformly distributed sites for the precipitation strengthening of Sm. The fine grain structure also facilitates better purification of grain boundaries and adjustment of the crystal structure by Y. At the same time, the precipitated phase of Sm can prevent grain boundary migration, which helps maintain the grain refinement effect of Pr. The strengthening effect of Y on grain boundaries provides a more stable structural basis for Pr and Sm to play their roles. The synergistic effect of these three elements significantly improves the strength of the bearing. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] A high-strength bearing comprises the following components by mass percentage: C 0.13%, Mn 0.3%, Si 0.27%, Mo 0.15%, Cr 1.2%, Al 0.23%, Cu 0.02%, Nb 0.1%, V 0.06%, W 0.1%, Sm 0.01%, Pr 0.003%, Y 0.01%, with the balance being Fe and other unavoidable impurities;

[0033] A manufacturing process for a high-strength bearing includes the following steps:

[0034] S1. Weigh the raw materials by mass percentage, melt the raw materials to form an alloy liquid, pour it into a steel ingot, cool it to room temperature, hot roll the steel ingot at 1200℃ for 6 hours, air cool it to 600℃ and then rapidly cool it to room temperature to obtain a steel billet.

[0035] S2. Roll the steel billet, heat it to 1000℃, hold it for 10 minutes, start rolling at 880℃, finish rolling at 780℃, then rapidly cool it to 650℃ and air cool it. After that, cut the rolled steel billet into sections, heat it again to 800℃, hold it for 60 minutes, and forge it at 850℃ according to a forging ratio of 1.5 to obtain forgings. Roll the forgings to obtain bearing semi-finished products.

[0036] S3. The bearing semi-finished product is normalized at 870℃, held for 3 hours, air-cooled, heated to 875℃ at a rate of 7℃ / min, and then carburized at a carbon potential of 1.20% for 5.5 hours.

[0037] S4. The carburized bearing semi-finished product is spheroidized annealed at 750℃ for 6 hours, cooled in the furnace, then heated to 850℃ and held for 20 minutes. It is then quenched in quenching oil at 65℃, tempered at 150℃ for 4 hours, and finely ground to obtain a high-strength bearing.

[0038] Example 2

[0039] A high-strength bearing comprises the following components by mass percentage: C 0.23%, Mn 0.4%, Si 0.67%, Mo 0.25%, Cr 4.2%, Al 0.33%, Cu 0.06%, Nb 0.2%, V 0.08%, W 0.2%, Sm 0.015%, Pr 0.005%, Y 0.015%, with the balance being Fe and other unavoidable impurities;

[0040] A manufacturing process for a high-strength bearing includes the following steps:

[0041] S1. Weigh the raw materials by mass percentage, melt the raw materials to form an alloy liquid, pour it into a steel ingot, cool it to room temperature, hot roll the steel ingot at 1250℃ for 4 hours, air cool it to 700℃ and then rapidly cool it to room temperature to obtain a steel billet.

[0042] S2. Roll the steel billet, heat it to 1200℃, hold it for 6 minutes, start rolling at 1000℃, finish rolling at 820℃, then rapidly cool it to 680℃ and air cool it. After that, cut the rolled steel billet into sections, heat it again to 900℃, hold it for 30 minutes, and forge it at 900℃ according to a forging ratio of 2.0 to obtain forgings. Roll the forgings to obtain bearing semi-finished products.

[0043] S3. The bearing semi-finished product is normalized at 920℃, held for 2 hours, air-cooled, heated to 875℃ at a rate of 12℃ / min, and then carburized at a carbon potential of 1.20% for 5.5 hours.

[0044] S4. The carburized bearing semi-finished product is spheroidized annealed at 780℃ for 4 hours, cooled in the furnace, then heated to 870℃ and held for 15 minutes. It is then quenched in quenching oil at 75℃, tempered at 200℃ for 2 hours, and finely ground to obtain a high-strength bearing.

[0045] Example 3

[0046] A high-strength bearing comprises the following components by mass percentage: C 0.18%, Mn 0.34%, Si 0.45%, Mo 0.20%, Cr 2.8%, Al 0.26%, Cu 0.04%, Nb 0.15%, V 0.07%, W 0.14%, Sm 0.013%, Pr 0.004%, Y 0.014%, with the balance being Fe and other unavoidable impurities;

[0047] A manufacturing process for a high-strength bearing includes the following steps:

[0048] S1. Weigh the raw materials by mass percentage, melt the raw materials to form an alloy liquid, pour it into a steel ingot, cool it to room temperature, hot roll the steel ingot at 1220℃ for 5 hours, air cool it to 660℃ and then rapidly cool it to room temperature to obtain a steel billet.

[0049] S2. Roll the steel billet, heat it to 1140℃, hold it for 8 minutes, start rolling at 900℃, finish rolling at 800℃, then rapidly cool it to 660℃ and air cool it. After that, cut the rolled steel billet into sections, heat it again to 850℃, hold it for 40 minutes, and forge it at 870℃ according to a forging ratio of 1.8 to obtain forgings. Roll the forgings to obtain bearing semi-finished products.

[0050] S3. The bearing semi-finished product is normalized at 900℃, held for 2.5h, air-cooled, heated to 875℃ at a rate of 10℃ / min, and then carburized at a carbon potential of 1.20% for 5.5h.

[0051] S4. The carburized bearing semi-finished product is spheroidized annealed at 765℃ for 5 hours, cooled in the furnace, then heated to 860℃ and held for 18 minutes. It is then quenched in quenching oil at 70℃, tempered at 180℃ for 3 hours, and finely ground to obtain a high-strength bearing.

[0052] Example 4

[0053] The difference between this embodiment and Embodiment 3 lies only in the presence of a high-strength bearing composed of the following components by mass percentage: C 0.18%, Mn 0.34%, Si 0.45%, Mo 0.20%, Cr 2.8%, Al 0.26%, Cu 0.04%, Nb 0.15%, V 0.07%, W 0.14%, Sm 0.012%, Pr 0.003%, Y 0.013%, with the balance being Fe and other unavoidable impurities.

[0054] Example 5

[0055] The difference between this embodiment and Embodiment 3 lies only in the presence of a high-strength bearing composed of the following components by mass percentage: C 0.18%, Mn 0.34%, Si 0.45%, Mo 0.20%, Cr 2.8%, Al 0.26%, Cu 0.04%, Nb 0.15%, V 0.07%, W 0.14%, Sm 0.011%, Pr 0.002%, Y 0.012%, with the balance being Fe and other unavoidable impurities.

[0056] Example 6

[0057] The difference between this embodiment and Embodiment 3 lies only in the presence of a high-strength bearing composed of the following components by mass percentage: C 0.18%, Mn 0.34%, Si 0.45%, Mo 0.20%, Cr 2.8%, Al 0.26%, Cu 0.04%, Nb 0.15%, V 0.07%, W 0.14%, Sm 0.01%, Pr 0.003%, Y 0.01%, with the balance being Fe and other unavoidable impurities.

[0058] Example 7

[0059] The difference between this embodiment and embodiment 4 is only that in step S2 of the manufacturing process of a high-strength bearing, the bearing semi-finished product is normalized at 900°C, held at that temperature for 2.5 hours, air-cooled, heated to 900°C at a rate of 7°C / min, and then carburized at a carbon potential of 0.85% for 7.5 hours.

[0060] Example 8

[0061] The difference between this embodiment and embodiment 4 is only that a three-stage carburizing process is used in step S2 of the manufacturing process of a high-strength bearing: the bearing semi-finished product is normalized at 900°C, held for 2.5 hours, air-cooled, and then carburized. In the first stage of carburizing, the carbon potential is 1.00%, the temperature is increased to 880°C at a rate of 10°C / min, and the holding time is 3.3 hours.

[0062] In the second stage of carburizing treatment, the carbon potential is 0.90%, the temperature is increased to 885℃ at a rate of 10℃ / min, and the holding time is 1.2h.

[0063] In the third stage of carburizing treatment, the carbon potential is 0.80%, and the temperature is increased to 900℃ at a rate of 10℃ / min, with a holding time of 1h.

[0064] Example 9

[0065] The difference between this embodiment and embodiment 4 is only that a three-stage carburizing process is used in step S2 of the manufacturing process of a high-strength bearing: the bearing semi-finished product is normalized at 900°C, held for 2.5 hours, air-cooled, and then carburized. In the first stage of carburizing, the carbon potential is 1.00%, the temperature is increased to 875°C at a rate of 10°C / min, and the holding time is 4.3 hours.

[0066] In the second stage of carburizing treatment, the carbon potential is 0.90%, the temperature is increased to 890℃ at a rate of 10℃ / min, and the holding time is 2.2h.

[0067] In the third stage of carburizing treatment, the carbon potential is 0.80%, and the temperature is increased to 895℃ at a rate of 10℃ / min, with a holding time of 2h.

[0068] Example 10

[0069] The only difference between this embodiment and Embodiment 8 is that the carbon potential is 1.05% in the first carburizing treatment, 0.95% in the second carburizing treatment, and 0.85% in the third carburizing treatment.

[0070] Example 11

[0071] The only difference between this embodiment and Embodiment 8 is that the carbon potential is 1.20% in the first carburizing treatment, 1.02% in the second carburizing treatment, and 0.92% in the third carburizing treatment.

[0072] Example 12

[0073] The only difference between this embodiment and Embodiment 8 is that the carbon potential is 1.25% in the first carburizing treatment, 1.10% in the second carburizing treatment, and 1.00% in the third carburizing treatment.

[0074] Comparative Example 1

[0075] The only difference between this comparative example and Example 3 is that Sm is not added.

[0076] Comparative Example 2

[0077] The only difference between this comparative example and Example 3 is that Pr is not added.

[0078] Comparative Example 3

[0079] The only difference between this comparative example and Example 3 is that Y is not added.

[0080] The high-strength bearings obtained in Examples 1-12 and Comparative Examples 1-3 were tested according to the following method:

[0081] 1. Tensile strength: Tested according to the method specified in GB / T 228.1-2021 "Metallic materials, tensile testing - Part 1: Test at room temperature";

[0082] 2. Corrosion rate: The test method is specified in GB / T 19746-2018 "Corrosion of metals and alloys - Salt solution immersion test", and the test time is 30 days.

[0083] The test results are shown in the table below:

[0084] Table 1 Performance test results of the high-strength bearings prepared in Examples 1-12 and Comparative Examples 1-3

[0085]

[0086] 1. Compared with Comparative Examples 1 to 3, the bearings prepared in Examples 1 to 12 have better tensile strength than the bearings prepared in Comparative Examples 1 to 3, indicating that the combined use of Pr, Sm and Y can significantly improve the strength of the bearing.

[0087] 2. Compared with Examples 3 to 6, the bearings obtained in Examples 4 to 5 have significantly higher tensile strength than those obtained in Examples 3 and 6, indicating that further limiting the mass percentages of Pr, Sm, and Y to 0.025% ≤ Pr + Sm + Y ≤ 0.028% significantly improves the strength of the bearing.

[0088] 3. Compared with Examples 8-12, the corrosion rate of the bearings prepared in Examples 10-11 is much lower than that of the bearings prepared in Examples 4, 8-9 and 12. This shows that by using three-step carburizing and controlling the carbon potential to be 1.05%-1.20% in the first carburizing treatment, 0.95%-1.02% in the second carburizing treatment and 0.85%-0.92% in the third carburizing treatment, the corrosion resistance of the bearing can be improved.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength bearing, characterized in that, It is composed of the following components by mass percentage: C 0.13%~0.23%, Mn 0.3%~0.4%, Si 0.27%~0.67%, Mo 0.15%~0.25%, Cr 1.2%~4.2%, Al 0.23%~0.33%, Cu 0.02%~0.06%, Nb 0.1%~0.2%, V 0.06%~0.08%, W 0.1%~0.2%, Sm 0.01%~0.015%, Pr 0.002%~0.005%, Y 0.01%~0.015%, with the balance being Fe and other unavoidable impurities, and 0.025%≤Pr+Sm+Y≤0.028%; The manufacturing process of the high-strength bearing includes the following steps: S1. Weigh the raw materials according to the mass percentage, melt the raw materials to form an alloy liquid, pour it into a steel ingot, cool it to room temperature, and hot roll the steel ingot to obtain a steel billet; S2. The steel billet is rolled, the rolled steel billet is cut into sections, heated and forged to obtain forgings, and the forgings are rolled and expanded to obtain bearing semi-finished products; S3. The bearing semi-finished product is subjected to normalizing and carburizing treatment; S4. The carburized bearing semi-finished product is subjected to spheroidizing annealing, quenching, and tempering, and then precision grinding to obtain a high-strength bearing. The carburizing process includes a first carburizing process, a second carburizing process, and a third carburizing process. In the first stage of carburizing treatment, the carbon potential is 1.05%~1.20%, the heating temperature is 875~880℃, and the holding time is 3.3~4.3h; In the second stage of carburizing treatment, the carbon potential is 0.95%~1.02%, the heating temperature is 885~890℃, and the holding time is 1.2~2.2h; In the third stage of carburizing treatment, the carbon potential is 0.85%~0.92%, the heating temperature is 895~900℃, and the holding time is 1~2h.

2. A manufacturing process for a high-strength bearing, used to manufacture the high-strength bearing according to claim 1, characterized in that, Includes the following steps: S1. Weigh the raw materials according to the mass percentage, melt the raw materials to form an alloy liquid, pour it into a steel ingot, cool it to room temperature, and hot roll the steel ingot to obtain a steel billet; S2. The steel billet is rolled, the rolled steel billet is cut into sections, heated and forged to obtain forgings, and the forgings are rolled and expanded to obtain bearing semi-finished products; S3. The bearing semi-finished product is subjected to normalizing and carburizing treatment; S4. The carburized bearing semi-finished product is subjected to spheroidizing annealing, quenching, and tempering, and then precision grinding to obtain a high-strength bearing. The carburizing process includes a first carburizing process, a second carburizing process, and a third carburizing process. In the first stage of carburizing treatment, the carbon potential is 1.05%~1.20%, the heating temperature is 875~880℃, and the holding time is 3.3~4.3h; In the second stage of carburizing treatment, the carbon potential is 0.95%~1.02%, the heating temperature is 885~890℃, and the holding time is 1.2~2.2h; In the third stage of carburizing treatment, the carbon potential is 0.85%~0.92%, the heating temperature is 895~900℃, and the holding time is 1~2h.

3. The manufacturing process of a high-strength bearing according to claim 2, characterized in that, The hot rolling treatment is performed at a temperature of 1200~1250℃ for 4~6 hours, followed by air cooling to 600~700℃ and then cooling to room temperature. The initial rolling temperature is 1000~1200℃, the holding time is 6~10min, the initial rolling temperature is 880~1000℃, the final rolling temperature is 780~820℃, and the temperature is cooled to 650~680℃ and then air-cooled. The heating temperature is 800~900℃, and the holding time is 30~60min; The forging ratio is 1.5~2.0, and the temperature is 850~900℃.

4. The manufacturing process of a high-strength bearing according to claim 2, characterized in that, The normalizing treatment is performed at a temperature of 870~920℃, held for 2~3 hours, and then air-cooled.

5. The manufacturing process of a high-strength bearing according to claim 2, characterized in that, The carbon potential in the carburizing treatment is 0.85%~1.20%, and the temperature is raised to 875~900℃ at a heating rate of 7~12℃ / min, and the holding time is 5.5~7.5h.

6. The manufacturing process of a high-strength bearing according to claim 2, characterized in that, The spheroidizing annealing treatment is performed at a temperature of 750~780℃ for 4~6 hours.

7. The manufacturing process of a high-strength bearing according to claim 2, characterized in that, The quenching treatment temperature is 850~870℃, held for 15~20min, and then oil quenched. The tempering treatment is performed at a temperature of 150~200℃ for 2~4 hours.

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