A double carburizing process for G13Cr4Mo4Ni4V steel ring

Abstract

A double carburizing process for G13Cr4Mo4Ni4V steel rings, the present invention relates to the field of double carburizing process for G13Cr4Mo4Ni4V steel bearing rings. The present invention is to solve the technical problem that the hardness and wear resistance of the current G13Cr4Ni4Mo4V steel bearing rings need to be improved. Method: 1. Use a vacuum carburizing furnace to carry out the first carburizing treatment; 2. High temperature tempering treatment; 3. Carburizing treatment again; 4. High temperature tempering treatment again; 5. Turning; 6. Heat treatment, completion. The G13Cr4Ni4Mo4V steel bearing rings obtained by the present invention have high hardness, high wear resistance, and high fatigue performance after vacuum carburizing heat treatment, which meets the use requirements of the product, while ensuring the good toughness of the core of the material and the size and shape of the carbide in the carburized layer. The process of the present invention is used to prepare bearing parts.

Description

Technical Field

[0001] The invention relates to the field of double carburizing technology for G13Cr4Mo4Ni4V steel bearing rings. Background Art

[0002] At present, after vacuum carburizing heat treatment, the surface hardness of G13Cr4Ni4Mo4V steel bearing rings is 60-63HRC, and the surface carbon concentration is 0.7-1.10%. The surface has a certain wear resistance, and the core has good toughness. However, as the bearing life is greatly improved and the operating conditions are more severe, the original carburizing indicators are no longer sufficient to meet the new operating conditions. Therefore, it is a general trend to improve the surface wear resistance and fatigue resistance of bearing parts. Summary of the Invention

[0003] In order to solve the technical problem that the hardness and wear resistance of G13Cr4Ni4Mo4V steel bearing rings need to be improved, the present invention provides a double carburizing process for G13Cr4Mo4Ni4V steel rings.

[0004] A double carburizing process for a G13Cr4Mo4Ni4V steel ferrule is specifically carried out in the following steps:

[0005] 1. Carburize the G13Cr4Mo4Ni4V steel ferrule workpiece using a vacuum carburizing furnace;

[0006] 2. Carburizing the G13Cr4Mo4Ni4V steel ring workpiece in step 1 and subjecting it to high temperature tempering treatment;

[0007] 3. Carburizing the G13Cr4Mo4Ni4V steel ferrule workpiece after the treatment in step 2 again using a vacuum carburizing furnace;

[0008] 4. The G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 3 is subjected to three high-temperature tempering treatments;

[0009] 5. Turning the G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 4 to obtain a steel ferrule workpiece;

[0010] 6. Heat treat the steel ring workpiece processed in step 5 to complete the process.

[0011] Furthermore, the carburizing process described in step 1 is: vacuum low-pressure pulse carburizing performed alternately by acetylene carburizing and nitrogen diffusion, controlling the carburizing temperature to 950-980°C, the carburizing pressure to 6-10 mbar, the carburizing gas flow rate to 1200-1800 nL / h, the carburizing time to 60-90 min, and the number of carburizing pulses to 10-15.

[0012] Furthermore, the temperature of the high temperature tempering treatment in step 2 is 650-700° C., the treatment time is 3-5 hours, and cooling is performed using 1.2-5 bar nitrogen.

[0013] Furthermore, the carburizing process described in step three is: vacuum low-pressure pulse carburizing performed alternately by acetylene carburizing and nitrogen diffusion, controlling the carburizing temperature to 950-980°C, the carburizing pressure to 6-10 mbar, the carburizing gas flow rate to 1200-1800 nL / h, the carburizing time to 700-750 min, and the number of carburizing pulses to 25-35.

[0014] Furthermore, in step 4, the temperature of each high-temperature tempering treatment is 650-700° C., the treatment time is 3-5 hours, and cooling is performed using 1.2-5 bar nitrogen.

[0015] Furthermore, the heat treatment temperature in step six is ​​1080-1120° C., the treatment time is 30-60 min, and cooling is performed using 1.5-5 bar nitrogen.

[0016] The purpose of turning in step five is to turn off the carburized layer of the workpiece that does not need to be carburized.

[0017] Beneficial effects of the present invention:

[0018] The G13Cr4Ni4Mo4V steel bearing ring obtained by the present invention is subjected to vacuum carburizing heat treatment and has high hardness, high wear resistance and high fatigue performance, which meets the use requirements of the product and ensures the good toughness of the core of the material and the size and shape of the carbide in the carburized layer.

[0019] Through the double carburizing process test of G13Cr4Ni4Mo4V steel bearing rings, the surface hardness of the rings reached 62-66HRC, the surface carbon concentration increased to 1.15%-1.50%, and the core hardness remained at 40-47HRC. This solved the problem of insufficient surface hardness of the material in traditional carburizing, greatly improved the wear resistance and fatigue resistance of the bearings, and finally obtained reasonable double carburizing process parameters for G13Cr4Ni4Mo4V steel bearing rings.

[0020] The process of the present invention is used for preparing bearing parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a graph showing the surface carbon concentration gradient of the G13Cr4Mo4Ni4V steel ferrule prepared in Example 1;

[0022] Figure 2 This is a hardness gradient diagram of the G13Cr4Mo4Ni4V steel ferrule prepared in Example 1;

[0023] Figure 3This is the organizational diagram of the G13Cr4Mo4Ni4V steel ferrule after the existing carburizing process (one-stage normal carburizing);

[0024] Figure 4 This is the organizational diagram of the G13Cr4Mo4Ni4V steel ferrule prepared in Example 1. DETAILED DESCRIPTION

[0025] Specific embodiment 1: This embodiment is a double carburizing process of a G13Cr4Mo4Ni4V steel ring, which is specifically carried out in the following steps:

[0026] 1. Carburize the G13Cr4Mo4Ni4V steel ferrule workpiece using a vacuum carburizing furnace;

[0027] 2. Carburizing the G13Cr4Mo4Ni4V steel ring workpiece in step 1 and subjecting it to high temperature tempering treatment;

[0028] 3. Carburizing the G13Cr4Mo4Ni4V steel ferrule workpiece after the treatment in step 2 again using a vacuum carburizing furnace;

[0029] 4. The G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 3 is subjected to three high-temperature tempering treatments;

[0030] 5. Turning the G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 4 to obtain a steel ferrule workpiece;

[0031] 6. Heat treat the steel ring workpiece processed in step 5 to complete the process.

[0032] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the carburizing process in step 1 is vacuum low-pressure pulse carburizing using alternating acetylene carburizing and nitrogen diffusion, with a carburizing temperature of 950-980°C, a carburizing pressure of 6-10 mbar, a carburizing gas flow rate of 1200-1800 nL / h, a carburizing time of 60-90 minutes, and 10-15 carburizing pulses. Other steps are the same as those in specific embodiment 1.

[0033] Specific embodiment 3: This embodiment differs from specific embodiments 1 or 2 in that the high-temperature tempering treatment in step 2 is performed at a temperature of 650-700°C for 3-5 hours and is cooled with 1.2-5 bar nitrogen. Other aspects are the same as specific embodiments 1 or 2.

[0034] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the carburizing process in step 3 is vacuum low-pressure pulse carburizing using alternating acetylene carburizing and nitrogen diffusion, with a carburizing temperature of 950-980°C, a carburizing pressure of 6-10 mbar, a carburizing gas flow rate of 1200-1800 nL / h, a carburizing time of 700-750 minutes, and 25-35 carburizing pulses. Other aspects are the same as specific embodiments 1 to 3.

[0035] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the temperature of each high-temperature tempering treatment in step 4 is 650-700°C, the treatment time is 3-5 hours, and cooling is performed with 1.2-5 bar nitrogen. Other aspects are the same as specific embodiments 1 to 4.

[0036] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the heat treatment temperature in step 6 is 1080-1120°C, the treatment time is 30-60 minutes, and cooling is performed using 1.5-5 bar nitrogen. Other aspects are the same as specific embodiments 1 to 5.

[0037] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or more specific embodiments can also achieve the purpose of the invention.

[0038] Example 1:

[0039] This embodiment provides a double carburizing process for a G13Cr4Mo4Ni4V steel ferrule, which is specifically carried out in the following steps:

[0040] 1. Carburizing a G13Cr4Mo4Ni4V steel ferrule workpiece using a vacuum carburizing furnace; the carburizing process comprises: vacuum low-pressure pulse carburizing using alternating acetylene carburizing and nitrogen diffusion, with a carburizing temperature of 950-980°C, a carburizing pressure of 6-10 mbar, a carburizing gas flow rate of 1200-1800 nL / h, a carburizing time of 60-90 minutes, and 10-15 carburizing pulses;

[0041] 2. Carburizing the G13Cr4Mo4Ni4V steel ring in step 1 and subjecting it to high-temperature tempering treatment at a temperature of 650-700°C for 3-5 hours; cooling with nitrogen at 1.2-5 bar;

[0042] 3. Carburizing the G13Cr4Mo4Ni4V steel ferrule workpiece after the treatment in step 2 again using a vacuum carburizing furnace; the carburizing process is as follows: vacuum low-pressure pulse carburizing using acetylene carburizing and nitrogen diffusion alternately, controlling the carburizing temperature to 950-980°C, the carburizing pressure to 6-10 mbar, the carburizing gas flow rate to 1200-1800 nL / h, the carburizing time to 700-750 min, and the number of carburizing pulses to 25-35;

[0043] 4. The G13Cr4Mo4Ni4V steel ring workpiece treated in step 3 is subjected to three high-temperature tempering treatments; each high-temperature tempering treatment is performed at a temperature of 650-700°C for 3-5 hours; and cooling is performed using 1.2-5 bar nitrogen gas;

[0044] 5. Turning the G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 4 to obtain a steel ferrule workpiece;

[0045] 6. Heat-treat the steel ferrule workpiece processed in step 5, control the heat treatment temperature to 1080-1120° C., and the treatment time to 30-60 min; and cool with 1.5-5 bar nitrogen to complete.

[0046] The G13Cr4Mo4Ni4V steel ferrule obtained in this example was tested.

[0047] Figure 1 This is a surface carbon concentration gradient diagram of the G13Cr4Mo4Ni4V steel ferrule prepared in Example 1. It can be seen from the figure that the surface carbon concentration of the steel ferrule is significantly improved after double carburizing treatment, and the surface carbon concentration can reach 1.9%. After removing the grinding allowance of 0.5mm, it can still reach 1.45%.

[0048] Figure 2 This is a hardness gradient diagram of the G13Cr4Mo4Ni4V steel ferrule prepared in Example 1. It can be seen from the figure that the surface hardness of the steel ferrule after double carburizing treatment reaches 66HRC, and the surface hardness of the finished product can reach 65HRC after removing and grinding the allowance of 0.5mm, which is an improvement compared with the existing process.

[0049] Figure 3 This is the organizational diagram of the G13Cr4Mo4Ni4V steel ferrule after the existing carburizing process (one-stage normal carburizing);

[0050] Figure 4 This is the organizational diagram of the G13Cr4Mo4Ni4V steel ferrule prepared in Example 1;

[0051] contrast Figure 3 and Figure 4It can be seen that the number of carbides increases significantly after double carburizing, and the size of carbides increases significantly, thereby improving the wear resistance and fatigue performance of the bearing.

Claims

1. A double carburizing process for G13Cr4Mo4Ni4V steel ferrule, characterized in that The process is specifically carried out in the following steps:

1. Carburize the G13Cr4Mo4Ni4V steel ferrule workpiece using a vacuum carburizing furnace; 2. Carburizing the G13Cr4Mo4Ni4V steel ring workpiece in step 1 and subjecting it to high temperature tempering treatment; 3. Carburizing the G13Cr4Mo4Ni4V steel ferrule workpiece after the treatment in step 2 again using a vacuum carburizing furnace; 4. The G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 3 is subjected to three high-temperature tempering treatments; 5. Turning the G13Cr4Mo4Ni4V steel ferrule workpiece processed in step 4 to obtain a steel ferrule workpiece; 6. Heat treat the steel ferrule workpiece processed in step 5 to complete the process; The carburizing process of step 1 and step 3 is as follows: vacuum low-pressure pulse carburizing is performed alternately by acetylene carburizing and nitrogen diffusion, the carburizing temperature is controlled at 950-980°C, the carburizing pressure is 6-10 mbar, and the carburizing gas flow rate is 1200-1800 nL / h; wherein the carburizing time of step 1 is 60-90 min, and the carburizing pulses are 10-15; the carburizing time of step 3 is 700-750 min, and the carburizing pulses are 25-35; The high temperature tempering treatment in step 2 and each high temperature tempering treatment in step 4 is as follows: the temperature is 650-700°C, the treatment time is 3-5 hours, and the cooling is carried out using 1.2-5 bar nitrogen; The heat treatment temperature in step 6 is 1080-1120° C., and the treatment time is 30-60 min; cooling is performed using 1.5-5 bar nitrogen.

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