A rim forging process

Abstract

The present application relates to the technical field of metal material processing, and particularly relates to a steel ring forging process, which comprises the following steps: S1, heating a steel ingot to an initial forging temperature of 1150 DEG C to 1250 DEG C; S2, adopting a wide flat anvil high-temperature strong pressing method, with an anvil width ratio of 0.6 to 0.8 and a reduction rate of 20%; S3, forming a pre-hole with a diameter of 1 / 3 to 1 / 2 of the diameter of the steel ingot in the center of the steel ingot after forging and pressing through a punching process; S4, expanding the hole by adopting a ring rolling mill, with a rolling expansion ratio of the driving roller to the core roller of 2.5 to 3.0; S5, making the outer diameter of the steel ring reach the design size through a multi-pass rolling process; S6, adopting air cooling or mist cooling, with a cooling rate controlled in the range of 50 DEG C / h to 80 DEG C / h; and S7, comprising deburring, surface polishing and size precision inspection. The present application solves the technical problems that the existing steel ring is prone to causing internal cracks and residual stress of the steel ingot in the forging and pressing process, and is prone to causing low size precision of the steel ring in the rolling expansion and forming.

Description

Technical Field

[0001] This invention relates to the field of metal material processing technology, and in particular to a steel ring forging process. Background Technology

[0002] Currently, steel rim forging is an important branch of the machinery manufacturing industry, widely used in automotive, aviation, aerospace, energy, and other sectors. As a key component, the quality and performance of the steel rim directly affect the operational stability and safety of the entire mechanical system. Therefore, improving the quality of steel rim forging has always been a focus of technological research and development in this field.

[0003] The forging process of steel rims involves multiple steps, including heating, forging, drilling, roll forming, roll pressing, cooling, and subsequent processing. The process parameters and operating conditions at each step significantly impact the final quality of the steel rim. Although existing steel rim forging technology has made some progress, certain defects and shortcomings still exist in actual production, making it difficult to further improve the quality of forged steel rims. The main defects of existing steel rim forging technology are as follows:

[0004] 1. During the forging process, improper control of the reduction amount and reduction rate may lead to uneven deformation of the steel ingot, resulting in internal cracks or residual stress, which will affect the mechanical properties of the steel ring.

[0005] 2. During the roll forming and expansion process, improper control of parameters such as roll ratio, feed speed, and rolling temperature may lead to problems such as low dimensional accuracy and large ellipticity error in the steel ring. Summary of the Invention

[0006] Therefore, in view of the above problems, the present invention proposes a steel ring forging process, which solves the technical problems that existing steel rings are prone to internal cracks and residual stress in the steel ingot during the forging process, and the steel rings are prone to low dimensional accuracy during roll forming and hole expansion.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a steel ring forging process, comprising the following steps:

[0008] S1. Steel ingot heating: Heat the steel ingot to the initial forging temperature of 1150℃~1250℃. The holding time is calculated based on the weight of the steel ingot at 1.5 hours / ton to ensure temperature uniformity of ±10℃.

[0009] S2. Steel ingot forging: adopts wide flat anvil high temperature strong pressing method, anvil width ratio 0.6~0.8, reduction rate 20%, and single reduction amount not exceeding 30% of steel ingot height;

[0010] S3. Steel ingot punching: A pre-hole with a diameter of 1 / 3 to 1 / 2 of the steel ingot diameter is formed in the center of the forged steel ingot through a punching process;

[0011] S4. Steel ring roll expansion: The expansion is carried out using a ring mill. The expansion ratio between the drive roll and the core roll is 2.5 to 3.0, the feed speed is 8 to 15 mm / s, and the rolling temperature is controlled at 1050℃ to 1100℃.

[0012] S5. Steel ring roll forming: Through a multi-pass roll forming process, the outer diameter of the steel ring reaches the design size, the deformation of a single pass does not exceed 15%, and the total deformation is ≥60%.

[0013] S6. Steel ring cooling: Air cooling or mist cooling is adopted, and the cooling rate is controlled at 50℃ / h~80℃ / h to avoid surface cracks.

[0014] S7. Post-processing: including deburring, surface polishing and dimensional accuracy inspection.

[0015] Furthermore, in the steel ingot heating step, when the initial temperature of the steel ingot is ≥600℃, a hot conveying process is adopted, and the holding time is shortened by 20%; when the initial temperature of the steel ingot is <600℃, a cold conveying process is adopted, and the holding time is increased by 15%.

[0016] Furthermore, in the steel ingot forging step, a two-stage pressing process is adopted, with a 10% anvil width overlap left between the two pressing parts. When flipping and applying pressure, the anvil angle is ≥30° to ensure that the billet is uniformly compacted.

[0017] Furthermore, in the steel ring rolling and hole expansion step, the ratio of the drive roller radius to the core roller radius (R+r) / (Rr) is 2.5 to 3.0, the rolling line speed is controlled at 1.5 to 2.0 m / s, and the ring wall thickness reduction rate is ≥40%.

[0018] Furthermore, in the steel ring roll forming step, a rolling process with synchronous control of radial and axial directions is adopted, the ratio of axial feed to radial feed is 1:2 to 1:3, and the ellipticity error of the ring is ≤0.5mm.

[0019] Furthermore, in the steel ring roll forming and hole enlarging step, the initial height-to-thickness ratio of the ring is ≤6:1. When the height-to-thickness ratio exceeds 6:1, a pre-rolling groove process is adopted, with the groove depth being 10% to 15% of the wall thickness and the width being 20% ​​to 25% of the wall thickness.

[0020] Furthermore, in the steel ring cooling step, when the steel ring wall thickness is ≥50mm, a staged cooling process is adopted, and the specific steps are as follows:

[0021] S61. Fog Cooling Stage: Place the steel ring in a fog cooling environment and control the cooling rate at 60℃ / h~80℃ / h until the surface temperature of the steel ring drops to 800℃.

[0022] S62. Air cooling stage: Transfer the steel ring to an air cooling environment and control the cooling rate at 40℃ / h~60℃ / h until the surface temperature of the steel ring drops to 400℃.

[0023] S63. Slow cooling stage: Place the steel ring in an insulated environment and control the cooling rate at 10℃ / h~20℃ / h until the surface temperature of the steel ring drops to room temperature.

[0024] When the steel ring wall thickness is less than 50mm, a continuous air cooling process is adopted, and the cooling rate is controlled at 50℃ / h to 80℃ / h to avoid surface cracks.

[0025] Furthermore, the slow cooling phase includes the following steps:

[0026] S631, Heat preservation: The steel ring is placed in a heat preservation device with temperature monitoring and automatic adjustment function. The device can adjust the heating power according to the real-time temperature of the steel ring to ensure a stable cooling rate.

[0027] S632, Cooling rate control: The cooling rate is controlled at 8℃ / h to 15℃ / h in the range of 400℃ to 300℃; at 5℃ / h to 10℃ / h in the range of 300℃ to 200℃; and at 3℃ / h to 8℃ / h in the range of 200℃ to room temperature.

[0028] S633. Ambient Atmosphere Control: During the slow cooling stage, inert gas is introduced into the insulation device to reduce oxidation on the steel ring surface. At the same time, the humidity inside the device is controlled to prevent cracks from forming on the steel ring surface due to humidity changes.

[0029] Furthermore, the slow cooling stage also includes the following steps:

[0030] S634. Vibration treatment: During the slow cooling process, the steel ring can be subjected to low-frequency vibration treatment. The vibration frequency is controlled at 50Hz to 100Hz and the amplitude is controlled at 0.1mm to 0.5mm to promote the release of internal stress of the steel ring and reduce residual stress.

[0031] Furthermore, in the environmental atmosphere control step, the inert gas introduced is nitrogen, and the oxygen concentration is maintained at 1-5%.

[0032] High-frequency, small-amplitude vibration is used in the temperature range of 400℃-300℃, and low-frequency, large-amplitude vibration is used when the temperature is below 300℃. The vibration is pulsed and intermittent.

[0033] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0034] 1. By precisely controlling the ingot heating temperature, holding time, forging parameters, drilling process, roll forming and expansion parameters, cooling rate, and subsequent processing steps, the quality of steel ring forging can be significantly improved. This process ensures high dimensional accuracy, uniform microstructure, and excellent mechanical properties in the steel rings, while effectively reducing surface cracks and internal residual stress, thus improving product qualification rate and service life.

[0035] 2. Adjusting the hot or cold feeding process flexibly according to the initial temperature of the steel ingot, and shortening or increasing the holding time accordingly, can improve production efficiency and reduce energy consumption. This adjustment ensures the uniformity of the steel ingot temperature during the heating process, avoiding local overheating or underheating, and laying a good foundation for subsequent forging steps.

[0036] 3. Employing a two-stage pressing process while maintaining anvil width overlap and staggered anvil angle ensures uniform compaction of the billet, reducing internal cracks and residual stress. This process improves the forging quality of steel rings, resulting in a denser internal structure and superior mechanical properties.

[0037] 4. By precisely controlling the rolling ratio of the drive roller and the core roller, the rolling speed, and the ring wall thickness reduction rate, the rolling expansion process of the steel ring can be optimized, improving dimensional accuracy and forming quality. This process reduces the generation of cracks and defects during the expansion process, improving the surface quality and mechanical properties of the steel ring.

[0038] 5. Employing a rolling process with simultaneous radial and axial control, and precisely controlling the ratio of axial to radial feed, effectively reduces ellipticity errors during the steel ring roll forming process. This process improves the dimensional accuracy and appearance quality of the steel ring, meeting the requirements of high-precision applications.

[0039] 6. For rings with a thickness ratio exceeding 6:1, the pre-rolled groove process can effectively reduce cracks and defects during the hole expansion process. This process improves the forming quality and mechanical properties of the steel ring, while reducing material waste and production costs.

[0040] 7. By flexibly employing staged cooling or continuous air cooling processes based on the steel ring wall thickness and precisely controlling the cooling rate, surface cracks and internal unevenness can be effectively avoided. This process improves the cooling quality and mechanical properties of the steel ring while reducing deformation and cracking during the cooling process.

[0041] 8. During the slow cooling stage, the use of insulation devices and temperature monitoring and automatic adjustment functions ensures a stable cooling rate and reduces internal stress and crack formation. This process improves the cooling quality and mechanical properties of the steel ring, while reducing the defect rate during production.

[0042] 9. Applying low-frequency vibration to the steel ring during the slow cooling process promotes stress release within the ring and reduces residual stress. This process improves the mechanical properties and service life of the steel ring, while reducing cracks and fractures caused by stress concentration during use.

[0043] 10. Introducing inert gases such as nitrogen during the environmental atmosphere control step, and controlling oxygen concentration and humidity, can reduce oxidation of the steel rim surface and cracks caused by humidity changes. This process improves the surface quality and corrosion resistance of the steel rim, while extending its service life. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0045] Figure 2 This is a schematic diagram of a staged cooling process.

[0046] Figure 3 This is a schematic diagram of the process flow for the slow cooling stage.

[0047] Figure 4 This is a schematic diagram of the structure of the present invention.

[0048] Figure 5 yes Figure 4 A schematic diagram of the structure in which the middle support mechanism cooperates with the second roller section.

[0049] Figure 6 This is a schematic diagram of the structure of the supporting components and the metal ring.

[0050] Figure 7 yes Figure 5 Enlarged view of point A in the middle.

[0051] Figure label:

[0052] 1. Frame; 2. Sliding seat; 21. Pushing cylinder; 3. Rolling mechanism; 33. Rotating motor; 31. First rolling section; 32. Second rolling section; 4. Support roller; 41. First roller section; 42. Second roller section; 43. Transition arc surface; 51. Support plate; 52. Swing drive device; 511. Recessed part; 512. Flexible buffer layer; 513. Wear-resistant material layer; 61. Lifting cylinder; 62. Lifting plate; 71. Supporting cylinder; 72. Top pressure roller; 73. Rotating cylinder; 9. Metal ring. Detailed Implementation

[0053] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0054] refer to Figures 1 to 3 This embodiment provides a steel ring forging process, including the following steps:

[0055] S1. Steel ingot heating: Heat the steel ingot to the initial forging temperature of 1150℃~1250℃. The holding time is calculated based on the weight of the steel ingot at 1.5 hours / ton to ensure temperature uniformity of ±10℃.

[0056] S2. Steel ingot forging: adopts wide flat anvil high temperature strong pressing method, anvil width ratio 0.6~0.8, reduction rate 20%, and single reduction amount not exceeding 30% of steel ingot height;

[0057] S3. Steel ingot punching: A pre-hole with a diameter of 1 / 3 to 1 / 2 of the steel ingot diameter is formed in the center of the forged steel ingot through a punching process;

[0058] S4. Steel ring roll expansion: The expansion is carried out using a ring mill. The expansion ratio between the drive roll and the core roll is 2.5 to 3.0, the feed speed is 8 to 15 mm / s, and the rolling temperature is controlled at 1050℃ to 1100℃.

[0059] S5. Steel ring roll forming: Through a multi-pass roll forming process, the outer diameter of the steel ring reaches the design size, the deformation of a single pass does not exceed 15%, and the total deformation is ≥60%.

[0060] S6. Steel ring cooling: Air cooling or mist cooling is adopted, and the cooling rate is controlled at 50℃ / h~80℃ / h to avoid surface cracks.

[0061] S7. Post-processing: including deburring, surface polishing and dimensional accuracy inspection.

[0062] In the steel ingot heating step, when the initial temperature of the steel ingot is ≥600℃, a hot conveying process is adopted, and the holding time is shortened by 20%; when the initial temperature of the steel ingot is <600℃, a cold conveying process is adopted, and the holding time is increased by 15%.

[0063] In the steel ingot forging process, a two-stage pressing process is adopted, with a 10% anvil width overlap left between the two pressing stages. When flipping and applying pressure, the anvil angle is ≥30° to ensure that the billet is uniformly compacted.

[0064] In the steel ring rolling and reaming step, the ratio of the drive roller radius to the core roller radius (R+r) / (Rr) is 2.5 to 3.0, where R represents the drive roller radius and r represents the core roller radius. The rolling line speed is controlled at 1.5 to 2.0 m / s, and the ring wall thickness reduction rate is ≥40%.

[0065] In the steel ring roll forming and hole enlarging step, the initial height-to-thickness ratio of the ring is ≤6:1. When the height-to-thickness ratio exceeds 6:1, a pre-rolling groove process is adopted, with the groove depth being 10% to 15% of the wall thickness and the width being 20% ​​to 25% of the wall thickness.

[0066] In the steel ring roll forming step, a rolling process with synchronous control of radial and axial directions is adopted, the ratio of axial feed to radial feed is 1:2 to 1:3, and the ellipticity error of the ring is ≤0.5mm.

[0067] In the steel ring cooling step, when the steel ring wall thickness is ≥50mm, a staged cooling process is adopted, and the specific steps are as follows:

[0068] S61. Fog Cooling Stage: Place the steel ring in a fog cooling environment and control the cooling rate at 60℃ / h~80℃ / h until the surface temperature of the steel ring drops to 800℃.

[0069] S62. Air cooling stage: Transfer the steel ring to an air cooling environment and control the cooling rate at 40℃ / h~60℃ / h until the surface temperature of the steel ring drops to 400℃.

[0070] S63. Slow cooling stage: Place the steel ring in an insulated environment and control the cooling rate at 10℃ / h~20℃ / h until the surface temperature of the steel ring drops to room temperature.

[0071] When the steel ring wall thickness is less than 50mm, a continuous air cooling process is adopted, and the cooling rate is controlled at 50℃ / h to 80℃ / h to avoid surface cracks.

[0072] Of course, each stage of the fan cooling process can use either mist cooling or air cooling.

[0073] The slow cooling phase includes the following steps:

[0074] S631, Heat preservation: The steel ring is placed in a heat preservation device with temperature monitoring and automatic adjustment function. The device can adjust the heating power according to the real-time temperature of the steel ring to ensure a stable cooling rate.

[0075] S632, Cooling rate control: The cooling rate is controlled at 8℃ / h to 15℃ / h in the range of 400℃ to 300℃; at 5℃ / h to 10℃ / h in the range of 300℃ to 200℃; and at 3℃ / h to 8℃ / h in the range of 200℃ to room temperature.

[0076] S633. Ambient Atmosphere Control: During the slow cooling stage, inert gas is introduced into the insulation device to reduce oxidation on the steel ring surface. At the same time, the humidity inside the device is controlled to prevent cracks from forming on the steel ring surface due to humidity changes.

[0077] S634. Vibration treatment: During the slow cooling process, the steel ring can be subjected to low-frequency vibration treatment. The vibration frequency is controlled at 50Hz to 100Hz and the amplitude is controlled at 0.1mm to 0.5mm to promote the release of internal stress of the steel ring and reduce residual stress.

[0078] The insulation device is equipped with high-precision temperature sensors distributed around the steel ring and at key locations inside the device. These sensors can monitor the temperature of the steel ring and the ambient temperature inside the device in real time and accurately. The temperature sensors transmit the collected temperature data to the central control system for subsequent analysis and processing. The insulation device contains heating elements, such as electric heating wires or infrared heaters, which provide heat as needed to maintain a stable temperature inside the device. Based on the data transmitted from the temperature sensors, the central control system automatically adjusts the power of the heating elements to control the temperature inside the device. When the temperature is below the set value, the control system increases the power of the heating elements; when the temperature is above the set value, the control system reduces the power of the heating elements or stops heating.

[0079] In the ambient atmosphere control step, nitrogen is used as the inert gas, and the oxygen concentration is maintained at 1-5%. High-frequency, small-amplitude vibration is used in the temperature range of 300℃-400℃, while low-frequency, large-amplitude vibration is used below 300℃, with intermittent pulse vibration. Using inert gases such as nitrogen and controlling oxygen concentration and humidity in the ambient atmosphere control step reduces oxidation of the steel ring surface and cracks caused by humidity changes. This process improves the surface quality and corrosion resistance of the steel ring, while extending its service life. High-frequency, small-amplitude vibration in the higher temperature range promotes rapid release of internal stress in the steel ring, while avoiding surface damage or internal cracks caused by excessive vibration amplitude. Low-frequency, large-amplitude vibration in the lower temperature range more effectively promotes further release of internal stress in the steel ring, while reducing energy loss and equipment wear caused by excessively high vibration frequency. The intermittent pulse vibration method allows for more effective control of vibration energy input, avoiding stress concentration or excessive release within the steel ring caused by continuous vibration, thereby improving the vibration treatment effect and the overall quality of the steel ring. The surface quality and internal structure uniformity of the steel ring are improved, thereby reducing the risk of cracks and fractures caused by stress concentration or surface damage during use.

[0080] In the steel ring roll forming step, a closed-loop proportional control system is adopted to monitor the outer diameter of the ring in real time and automatically adjust the rolling force, with the outer diameter tolerance controlled within ±1mm.

[0081] The steel ring forging process is applicable to carbon steel, alloy steel and stainless steel materials, wherein the rolling temperature of carbon steel is 1100℃~1150℃, the rolling temperature of alloy steel is 1150℃~1200℃, and the rolling temperature of stainless steel is 1200℃~1250℃.

[0082] In the steel ring forging process, during the rolling and forming of the steel ring, an induction heating furnace can be used to replenish the temperature in real time to ensure that the temperature of the ring is higher than the recrystallization temperature of the material and to avoid work hardening.

[0083] In addition, in the steel ring roll forming process of step S5, a dual-station ring rolling mill is used to achieve the roll forming of the steel ring. (Reference) Figures 4 to 7 As shown, a dual-station ring rolling mill is used to roll and expand a metal ring 9. It includes a frame 1 and a sliding seat 2 that can slide up and down along the frame 1; a pushing cylinder 21 mounted on the frame 1 to drive the sliding seat 2; a rolling mechanism 3 rotatably mounted on the sliding seat 2; a rotating motor 33 that drives the rolling mechanism 3 to rotate; and a support roller 4 rotatably mounted on the frame 1 below the rolling mechanism 3. The support roller 4 supports the ring and cooperates with the rolling mechanism 3 to achieve rolling and expansion. The frame 1 is inclined at an angle β of 5-30 degrees to allow the support roller 4 to independently support the metal ring 9. The support roller 4 has a first roller portion 41 near the frame 1 and a second roller portion 42 located outside the first roller portion 41. The diameter of the second roller portion 42 is smaller than the diameter of the first roller portion 41. The rolling mechanism 3 includes a first rolling portion 31 that cooperates with the first roller portion 41 and a second rolling portion 32 that cooperates with the second roller portion 42.

[0084] The optimal tilt angle β is 10 degrees, which ensures independent support while also facilitating operation and observation.

[0085] The frame 1 is provided with a support mechanism for supporting the second roller section 42. The support mechanism is rotatably mounted on a support plate 51 on the frame 1 and a swing drive device 52 for driving the support plate 51 to move closer to or away from the second roller section 42. The support plate 51 is provided with a recess 511 that mates with the free end of the second roller section 42. The swing drive device 52 is a hydraulic cylinder.

[0086] The recessed portion 511 is an arc shape that matches the free end of the second roller portion 42, and the depth can be set according to actual needs, such as 10mm, to ensure good fit and support effect.

[0087] A flexible buffer layer 512 is disposed within the recessed portion 511, and a wear-resistant material layer 513 is disposed within the flexible buffer layer 512. The flexible buffer layer 512 may be made of rubber, which has good elasticity and shock absorption performance, and has a thickness of 5mm to provide sufficient buffer space. The wear-resistant material layer 513 may be made of polytetrafluoroethylene (PTFE), which has an extremely low coefficient of friction and excellent wear resistance. It has a thickness of 2mm to extend service life, or a ceramic coating may be used instead.

[0088] A lifting mechanism for lifting the metal ring 9 is provided on the frame 1 below the second roller section 42. The lifting mechanism includes a lifting cylinder 61 on the frame 1 and a lifting plate 62 on the piston rod of the lifting cylinder 61. The upper end face of the lifting plate 62 is inclined to give the metal ring 9 a tendency to move towards the first roller section 41. The upper end face of the lifting plate 62 is provided with anti-slip texture, the depth of which is 0.5-2mm, and the texture is wavy. The angle α between the upper end face of the lifting plate 62 and the axis of the supporting roller 4 is 5-15 degrees. In this design, the angle α is 7 degrees.

[0089] A transition arc surface 43 is provided between the first roller section 41 and the second roller section 42.

[0090] Support assemblies are respectively provided on both sides below the support roller 4 on the frame 1. The support assembly includes a support cylinder 71 with its bottom hinged to the frame 1, a top pressure roller 72 rotatably mounted on the piston rod of the support cylinder 71, and a rotating cylinder 73 with its bottom hinged to the frame 1. The piston rod of the rotating cylinder 73 is hinged to the support cylinder. The top pressure roller 72 can cooperate with the metal ring 9 on the first roller part 41 and / or the second roller part 42 to achieve support.

[0091] The aforementioned hydraulic cylinders are all standard hydraulic cylinders, and their stroke is controlled by a hydraulic system. The aforementioned support mechanism can also adopt other structures, as long as it can support the second roller section; it can also be omitted. The aforementioned lifting mechanism can also be other structures; its purpose is to lift the metal ring, allowing it to detach from the second roller section and enter the first roller section; it can also be omitted. The support assembly can also be other structures; its main function is to coordinate the two top rollers with the rolling mechanism to achieve the rolling and forming of the metal ring; it can also be omitted. The support assembly can be used for the final forming and support of the metal ring.

[0092] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A steel ring forging process, characterized in that, Includes the following steps: S1. Steel ingot heating: Heat the steel ingot to the initial forging temperature of 1150℃~1250℃. The holding time is calculated based on the weight of the steel ingot at 1.5 hours / ton to ensure temperature uniformity of ±10℃. S2. Steel ingot forging: adopts wide flat anvil high temperature strong pressing method, anvil width ratio 0.6~0.8, reduction rate 20%, and the single reduction amount does not exceed 30% of the steel ingot height; S3. Steel ingot punching: A pre-hole with a diameter of 1 / 3 to 1 / 2 of the steel ingot diameter is formed in the center of the forged steel ingot through a punching process; S4. Steel ring roll expansion: The expansion is carried out using a ring mill. The expansion ratio between the drive roll and the core roll is 2.5 to 3.0, the feed speed is 8 to 15 mm / s, and the rolling temperature is controlled at 1050℃ to 1100℃. S5. Steel ring roll forming: Through a multi-pass roll forming process, the outer diameter of the steel ring reaches the design size, the deformation of a single pass does not exceed 15%, and the total deformation is ≥60%; S6. Steel ring cooling: Air cooling or mist cooling is adopted, and the cooling rate is controlled at 50℃ / h~80℃ / h to avoid surface cracks. S7. Post-processing: including deburring, surface polishing and dimensional accuracy inspection; In the steel ring cooling step, when the steel ring wall thickness is ≥50mm, a staged cooling process is adopted, and the specific steps are as follows: S61. Fog Cooling Stage: Place the steel ring in a fog cooling environment and control the cooling rate at 60℃ / h~80℃ / h until the surface temperature of the steel ring drops to 800℃. S62. Air cooling stage: Transfer the steel ring to an air cooling environment and control the cooling rate at 40℃ / h~60℃ / h until the surface temperature of the steel ring drops to 400℃. S63. Slow cooling stage: Place the steel ring in an insulated environment and control the cooling rate at 10℃ / h~20℃ / h until the surface temperature of the steel ring drops to room temperature. When the steel ring wall thickness is less than 50mm, a continuous air cooling process is adopted, and the cooling rate is controlled at 50℃ / h to 80℃ / h to avoid surface cracks.

2. The steel ring forging process according to claim 1, characterized in that, In the steel ingot heating step, when the initial temperature of the steel ingot is ≥600℃, a hot conveying process is adopted, and the holding time is shortened by 20%; when the initial temperature of the steel ingot is <600℃, a cold conveying process is adopted, and the holding time is increased by 15%.

3. The steel ring forging process according to claim 1, characterized in that, In the steel ingot forging process, a two-stage pressing process is adopted, with a 10% overlap of the anvil width left between the two pressing stages. When flipping and applying pressure, the anvil angle is ≥30° to ensure that the billet is uniformly compacted.

4. The steel ring forging process according to claim 1, characterized in that, In the steel ring rolling expansion step, the difference between the radius of the driving roller and the radius of the core roller (R+r) / (Rr) is 2.5 to 3.0 compared with the sum of the radius of the driving roller and the radius of the core roller. The rolling speed is controlled at 1.5 to 2.0 m / s, and the ring wall thickness reduction rate is ≥40%.

5. The steel ring forging process according to claim 1, characterized in that, In the steel ring roll forming step, a rolling process with synchronous control of radial and axial directions is adopted, the ratio of axial feed to radial feed is 1:2 to 1:3, and the ellipticity error of the ring is ≤0.5mm.

6. The steel ring forging process according to claim 1, characterized in that, In the steel ring roll forming and hole enlargement step, the initial height-to-thickness ratio of the ring is ≤6:

1. When the height-to-thickness ratio exceeds 6:1, a pre-rolling groove process is adopted, with the groove depth being 10% to 15% of the wall thickness and the width being 20% ​​to 25% of the wall thickness.

7. The steel ring forging process according to claim 1, characterized in that, The slow cooling stage also includes the following steps: Vibration treatment: During the slow cooling stage, the steel ring can be subjected to low-frequency vibration treatment, with the vibration frequency controlled between 50Hz and 100Hz and the amplitude controlled between 0.1mm and 0.5mm, in order to promote the release of internal stress in the steel ring and reduce residual stress.

8. The steel ring forging process according to claim 7, characterized in that, During the slow cooling phase, the insulation device is filled with inert gas, specifically nitrogen, to maintain an oxygen concentration of 1-5%. High-frequency, small-amplitude vibration is used in the temperature range of 400℃-300℃, and low-frequency, large-amplitude vibration is used when the temperature is below 300℃. The vibration is pulsed and intermittent.

Images