Technological method for reducing inner diameter difference of upper end and lower end of asymmetric outer double-groove casing ring forge piece

Abstract

The invention discloses a process method for reducing the inner diameter difference of the upper end and the lower end of an asymmetric outer double-groove casing ring forge piece, which comprises the following steps of: performing taper compensation on the inner surface of a ring blank for rolling to obtain an inner conical section ring blank, and calculating the size of the inner conical section ring blank according to the principle that the volume is not changed before and after rolling; the inner diameter difference of the upper end and the lower end generated by rolling the asymmetric outer double-groove casing ring forge piece through the rectangular ring blank is reduced, a closed rolling combined driving roller and a core roller are designed to prevent the ring piece from moving up and down in the rolling process, and the rolling stability is guaranteed. A closed rolling combined driving roller and a core roller are used for rolling an inner conical section ring blank into an asymmetric outer double-groove casing ring forging, and a rolling speed curve of the core roller and the rotating speed of the driving roller are designed according to the volume change trend of each area in the rolling process. The method can ensure that the inner diameter difference of the upper end and the lower end of the asymmetric outer double-groove casing ring forging is within a reasonable range on the premise of not increasing the size of the ring blank.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation manufacturing, and in particular relates to a process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double-groove casing ring forging. Background Art

[0002] Aircraft engines are the power core of modern aircraft, and their performance and reliability directly affect the safety and stability of aircraft. Casing parts are one of the main components of aircraft engines. The manufacturing process of asymmetric outer double groove casing rings includes casing ring forging rolling and machining. The rolled casing ring forgings must not only meet the various performance index requirements of the asymmetric outer double groove casing parts matrix, but also must envelop the final asymmetric outer double groove casing parts. In order to reduce material costs and machining cycles, the outer dimensions of the asymmetric outer double groove casing ring forgings that envelop the final asymmetric outer double groove casing parts are required to be as small as possible.

[0003] In order to ensure that the final asymmetric outer double groove casing parts can be processed, a machining allowance of 8~10mm is usually added to the outer contour of the asymmetric outer double groove casing parts on one side. However, due to factors such as mold design and material flow distribution during rolling, there is a problem of inner diameter difference (10mm) between the upper and lower ends of the asymmetric outer double groove casing ring forging. According to the existing ring rolling process, it is necessary to increase the allowance for the inner diameter difference between the upper and lower ends on the basis of the machining allowance of 8~10mm, thereby increasing the total machining allowance, resulting in a longer machining cycle and greater material costs.

[0004] As can be seen from the above, the existing rolling process method for asymmetric outer double groove casing ring forgings only increases the size of the outer contour of the envelope part, and cannot improve the problem of inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forgings, and it is difficult to meet the high precision requirements of the asymmetric outer double groove casing ring forgings. Therefore, reducing the inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forgings is a key issue in the precision forming and manufacturing of aircraft engine casing ring forgings that needs to be solved urgently at this stage. Summary of the invention

[0005] The purpose of the present invention is to provide a process method for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging, which can ensure that the inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forging is within a reasonable range without increasing the volume of the ring blank.

[0006] The technical solution adopted by the present invention is: A process method for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging is disclosed. The inner surface of a ring blank for rolling is taper compensated to obtain an inner conical section ring blank, and the size of the inner conical section ring blank is calculated according to the principle of unchanged volume before and after rolling, so as to reduce the inner diameter difference between the upper and lower ends produced by rolling an asymmetric outer double groove casing ring forging with a rectangular ring blank. A combined driving roller and a core roller of closed rolling are designed to prevent the ring from moving up and down during rolling and ensure rolling stability. The inner conical section ring blank is rolled into an asymmetric outer double groove casing ring forging by using the combined driving roller and the core roller of closed rolling. According to the volume change trend of each region during the rolling process, the core roller rolling speed curve and the driving roller speed are designed, so as to ensure that the inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forging is within a reasonable range without increasing the volume of the ring blank.

[0007] Preferably, the method of performing taper compensation on the inner surface of the rolling ring blank to obtain the ring blank with an inner tapered cross-section is: Assume that the maximum outer diameter of the asymmetric outer double groove casing ring forging is , inner diameter is , height is , the groove depth is , groove radius is , the maximum groove width is , small groove width is The volume of the groove is , the volume after filling the groove is , its own volume is V; The maximum outer diameter of the asymmetric double groove casing ring forging As a reference, determine the outer diameter of the inner conical section ring blank , k is the equivalent rolling ratio; Inner conical section ring blank height

[0008] Inner surface slope of inner conical section ring blank

[0009] Inner surface taper of inner conical section ring blank

[0010] Volume of inner conical section ring blank

[0011] in, The inner diameter of the small end of the inner conical section ring blank, The inner diameter of the large end of the ring blank with an inner conical section; For , First, the asymmetric outer double groove casing ring forging is divided into five regions along the axial direction from the small end to the large end. The volumes corresponding to the five regions are , , , , The inner diameters of the five regions are , , , , , where the volume and inner diameter of the second and fourth regions are determined by the following formula

[0012]

[0013]

[0014]

[0015] Then, the inner surface slope of the inner conical section ring blank is obtained by the inner diameter difference between the second area and the fourth area. ,in is the vertical distance between the second area and the fourth area; the taper of the inner surface of the inner conical section ring blank ; According to the above formula, the outer diameter of the ring blank with a known inner conical section , Inner surface taper of inner conical section ring blank , Inner surface slope of inner conical section ring blank , Inner conical section ring blank height Based on the principle of equal volume before and after rolling, the inner diameter of the small end of the inner conical section ring is obtained. , inner diameter of the large end of the inner conical section ring blank ; Among them, the volume of the asymmetric outer double groove casing ring forging is , the volume of the groove part of the asymmetric outer double groove casing ring forging , the volume of the asymmetric outer double groove casing ring forging after filling the groove part .

[0016] Preferably, the equivalent rolling ratio k is 1.3~2.

[0017] The method of designing the combined drive roll and core roll of the closed rolling is: Since the shape of the driving roller when the inner conical section ring is rolled to the asymmetric outer double groove casing ring forging must correspond to the cross-sectional shape of the asymmetric outer double groove casing ring forging, the maximum diameter of the driving roller working surface is , minimum diameter And the core roller working surface diameter Determined by the following formula

[0018]

[0019]

[0020]

[0021] To prevent the ring from axial movement, add upper and lower baffles to the drive roller and increase the cavity height of the drive roller. = + , core roller height mm, is the axial play value, is the height of the asymmetric outer double groove casing ring forging; Cavity width when the driving roller and the core roller are closed ; in, The taper of the inner surface of the ring blank with inner conical section, The maximum outer diameter of the asymmetric outer double groove casing ring forging, The inner diameter of the asymmetric outer double groove casing ring forging is is the groove depth of the asymmetric outer double groove casing ring forging; is the friction angle, , is the friction coefficient; and They are the maximum and minimum closed center distances allowed by the ring rolling machine.

[0022] Preferably, the draft angle of the upper and lower baffles of the driving roller is 1-2°.

[0023] Preferably, the friction coefficient It is 0.1~0.4.

[0024] The method for designing the core roll rolling speed curve and the driving roll speed is: In the process of rolling asymmetric outer double groove casing ring forgings from inner conical ring billet, the volume of the second and fourth regions will decrease sharply when the outer diameter of the ring is rolled from D0 to D1, the volume of the second region will be compensated to the first and third regions, and the volume of the fourth region will be supplemented to the third and fifth regions, showing that the volume of the third region in the middle is the largest. Therefore, the feed speed of the core roller can be linearly increased in the early stage of rolling (0-t1)s, and the outer diameter of the ring is rolled from D1 to D1. k The volume of all regions reaches the maximum value when the ring is rolled to D3. Therefore, in the stage from D1 to D3, i.e. (t2-t3)s, the feed speed of the core roller is set to a fixed value to ensure the smooth rolling of the ring. k In the stage (t3-t4)s, the core roll feed speed is reduced and the rolling is gradually finished; Driving roller speed , is the maximum linear speed of the driving roller; Core roller feed speed satisfy

[0025]

[0026]

[0027]

[0028] in The outer diameter of the ring is The wall thickness at The outer diameter of the ring is The wall thickness at The outer diameter of the ring is The wall thickness at the time.

[0029] Preferably, the maximum linear speed of the driving roller is Take 0.7~1.4m / s.

[0030] The beneficial effects of the present invention are: The method can reduce the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging, and can ensure that the inner diameter difference between the upper and lower ends of a final asymmetric outer double groove casing ring forging is within a reasonable range without increasing the volume of the ring blank. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the asymmetric outer double groove casing ring forging in the present invention, in which the red dotted line indicates the difference in inner diameters of the upper and lower ends produced by the prior art.

[0032] Figure 2 It is a schematic diagram of volume distribution after the outer diameter of the ring blank for rolling is determined in the present invention.

[0033] Figure 3 It is a schematic diagram of the inner tapered cross-section ring blank in the present invention.

[0034] Figure 4 It is a schematic diagram of the combined driving rollers of the closed rolling in the present invention.

[0035] Figure 5 It is a curve diagram of volume change of each region during the ring rolling process of the present invention.

[0036] Figure 6 It is a schematic diagram of the curve of the core roller feed speed during the ring rolling process of the present invention.

[0037] Figure 7 Dimensional drawing of an asymmetric outer double groove casing ring forging in an embodiment of the present invention.

[0038] Figure 8 Dimensional drawing of the inner tapered section ring blank in an embodiment of the present invention.

[0039] Fig. 9 It is a schematic diagram of the assembly during rolling in an embodiment of the present invention.

[0040] Fig.10 Graph showing simulation results of an asymmetric outer double groove casing ring forging in an embodiment of the present invention.

[0041] Fig.11 This is a finished product picture of the asymmetric outer double groove casing ring forging in an embodiment of the present invention.

[0042] In the figure: 1-driving roller; 2-left guide roller; 3-core roller; 4-upper tapered roller; 5-lower tapered roller; 6-right guide roller. DETAILED DESCRIPTION

[0043] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0044] The present application discloses a process method for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging, and its purpose is to ensure that the inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forging is within a reasonable range without increasing the volume of the ring blank. The principle is: taper compensation is performed on the inner surface of the rolling ring blank to obtain an inner conical section ring blank, and the size of the inner conical section ring blank is calculated according to the principle of constant volume before and after rolling, so as to reduce the inner diameter difference between the upper and lower ends generated by rolling the asymmetric outer double groove casing ring forging with a rectangular ring blank, and a combined driving roller and a core roller of closed rolling are designed to prevent the ring from moving up and down during rolling and ensure rolling stability, and the inner conical section ring blank is rolled into an asymmetric outer double groove casing ring forging by using the combined driving roller and the core roller of closed rolling, and the core roller rolling speed curve and the driving roller speed are designed according to the volume change trend of each region during the rolling process, so as to ensure that the inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forging is within a reasonable range without increasing the volume of the ring blank.

[0045] This process method specifically adopts the following steps: S1. Perform taper compensation on the inner surface of the rolling ring blank to obtain an inner tapered section ring blank The dimensions of the asymmetric outer double groove casing ring forging are as follows: Figure 1 As shown, The maximum outer diameter of the asymmetric outer double groove casing ring forging, The inner diameter of the asymmetric outer double groove casing ring forging is is the height of the asymmetric outer double groove casing ring forging, is the groove depth of the asymmetric outer double groove casing ring forging, The groove radius of the asymmetric outer double groove casing ring forging is , They are the widths of the large groove and small groove of the asymmetric outer double groove casing ring forging, The volume of the groove of the asymmetric outer double groove casing ring forging. is the volume of the asymmetric outer double groove casing ring forging after the groove part is filled, and V is the volume of the asymmetric outer double groove casing ring forging.

[0046] The maximum outer diameter of the asymmetric outer double groove casing ring forging As a reference, determine the outer diameter of the inner conical section ring blank , k is the equivalent rolling ratio, which is 1.3~2.

[0047] Inner conical section ring blank height

[0048] Inner surface slope of inner conical section ring blank

[0049] Inner surface taper of inner conical section ring blank

[0050] Volume of inner conical section ring blank

[0051] in, The inner diameter of the small end of the inner conical section ring blank, It is the inner diameter of the large end of the inner conical section ring blank.

[0052] To obtain , First, the asymmetric outer double groove casing ring forging is divided into five regions along the axial direction from the small end to the large end. The volumes corresponding to the five regions are , , , , , get the outer diameter of the inner conical section ring blank The inner diameters of the last five regions are , , , , ,like Figure 2 As shown, the volume calculation and inner diameter calculation of areas ② and ④ are determined by the following formulas:

[0053]

[0054]

[0055]

[0056] Then the inner surface slope of the inner conical section ring blank is obtained by the inner diameter difference between the ② and ④ regions. ,in is the vertical distance between areas ② and ④; the taper of the inner surface of the inner conical section ring blank .

[0057] According to the above formula, the outer diameter of the ring blank with a known inner conical section , Inner surface taper of inner conical section ring blank , Inner surface slope of inner conical section ring blank , Inner conical section ring blank height Based on the principle of equal volume before and after rolling, the inner diameter of the small end of the inner conical section ring can be obtained. , inner diameter of the large end of the inner conical section ring blank , of which the volume of the asymmetric outer double groove casing ring forging is , the volume of the groove part of the asymmetric outer double groove casing ring forging , the outer cylindrical volume of the asymmetric outer double groove casing ring forging .

[0058] In this embodiment, the dimensions of the asymmetric outer double groove casing ring forging are as follows: Figure 7 As shown, mm, mm, mm, mm, 22.5mm, mm, mm, ensuring that the equivalent rolling ratio is between 1.3 and 2. After a large number of simulations and verifications, the rolling ratio K is selected as 1.3. The outer diameter of the inner conical section ring blank is determined by the above formula mm, divided into 5 areas such as Figure 3 , and obtain the area volume , , perform regional volume distribution of the ring blank, obtain the inner diameter value of each region of the ring blank, and obtain , , obtained by , , determine the taper of the inner surface of the inner conical section ring blank mm, inner surface slope of the inner conical section ring blank °, and then according to the principle of equal volume, the volume of the groove part

[0059] External cylindrical volume

[0060] Volume of asymmetric outer double groove casing ring forging V= =39420866.7

[0061] Final determination of the inner diameter of the small end of the inner conical section ring blank mm, inner diameter of the large end of the inner conical section ring blank mm, the final schematic diagram of the inner conical section ring blank is as follows Figure 8 shown.

[0062] S2. Design of combined drive rolls and core rolls for closed rolling When rolling the inner conical section ring to the asymmetric outer double groove casing ring forging, the shape of the driving roller must correspond to the cross-sectional shape of the asymmetric outer double groove casing ring forging. The maximum diameter of the driving roller working surface , minimum diameter And the core roller working surface diameter Determined by the following formula:

[0063]

[0064]

[0065]

[0066] To prevent the ring from axial movement, add upper and lower baffles of the driving roller, the draft angle of which is between 1-2°, and the cavity height of the driving roller = + , core roller height mm, is the axial play value, This is the height of the asymmetric outer double groove casing ring forging.

[0067] Cavity width when the driving roller and the core roller are closed .

[0068] in, The taper of the inner surface of the ring blank with inner conical section, The maximum outer diameter of the asymmetric outer double groove casing ring forging, The inner diameter of the asymmetric outer double groove casing ring forging is is the groove depth of the asymmetric outer double groove casing ring forging; is the friction angle, is the friction coefficient, between 0.1 and 0.4; and They are the maximum and minimum closed center distances allowed by the ring rolling machine respectively; In this example, the maximum diameter of the driving roller working surface during the rolling process of the asymmetric outer double groove casing ring forging mm, minimum diameter mm, driving roller cavity height mm and core roller diameter mm, core roller height mm. The assembly diagram of the rolling process of the asymmetric outer double groove casing ring forging is shown in Fig. 9 shown.

[0069] S3. Design the core roll rolling speed curve and drive roll speed Since the volume of each area will change during the rolling of the asymmetric outer double groove casing ring forging from the inner conical ring billet, the volume of areas ② and ④ will decrease sharply during the rolling process of the outer diameter of the ring from D0 to D1, and the volume of area ② will be compensated to areas ① and ③, and the volume of area ④ will be supplemented to areas ③ and ⑤, showing that the volume of the middle area ③ is the largest. Therefore, the feed speed of the core roller can be linearly increased in the early rolling stage (0-t1)s, and the outer diameter of the ring is rolled from D1 to D1. k The volume of all regions reaches the maximum value when the ring is rolled to D3. Therefore, the feed speed of the core roller can be set to a constant value in the stage from D1 to D3, i.e. (t2-t3)s, to ensure the smooth rolling of the ring. k In the stage (t3-t4)s, the core roller feed speed is reduced, the rolling gradually ends, and the core roller feed curve is obtained.

[0070] Driving roller speed , The maximum linear speed of the driving roller is 0.7~1.4m / s; Core roller feed speed satisfy

[0071]

[0072]

[0073]

[0074] in The outer diameter of the ring is The wall thickness at The outer diameter of the ring is The wall thickness at The outer diameter of the ring is The wall thickness at the time.

[0075] In this example, the linear speed of the driving roller is 0.7 m / s, so the driving roller speed n=0.2 rad / s, and the core roller feed speed , the outer diameter of the inner conical section ring blank mm rolled to mm, we can get mm, the volume of areas ② and ④ is greatly reduced and supplemented to other areas, that is, the core roller feed speed is It takes 9.5s to reach 0.5mm / s, and then takes it as the platform speed to reach When rolling to the outer diameter of the ring mm, then Rolled ring outer diameter mm.

[0076] The final forming effect of the asymmetric outer double groove casing ring forging is as follows Fig.10 As shown, the axial taper is 1.5mm, which greatly improves the ring accuracy.

[0077] This method distributes the volume of the rolling blank during the rolling forming process of the asymmetric outer double groove casing ring forging to prevent the problem of excessive difference in the inner diameters of the upper and lower ends of the asymmetric outer double groove casing ring forging due to factors such as mold design and material flow distribution during rolling; certain mold design and parameter design are performed on the rolling forming process to prevent the asymmetric outer double groove casing ring forging from failing to meet the various performance index requirements of the asymmetric outer double groove casing component matrix due to problems such as roller climbing and shaking of the ring. This method successfully rolled out an asymmetric outer double groove casing ring forging with an inner diameter difference of less than 1.5 mm between the upper and lower ends. The experimental results are shown in the figure below. Fig.11 , which solves the problem of large inner diameter difference of asymmetric outer double groove casing ring forgings after rolling.

[0078] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. A process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging, characterized in that: The inner surface of the ring blank for rolling is compensated for taper to obtain an inner conical section ring blank, and the size of the inner conical section ring blank is calculated according to the principle of unchanged volume before and after rolling, so as to reduce the inner diameter difference between the upper and lower ends of the rectangular ring blank when rolling an asymmetric outer double groove casing ring forging. A combined driving roller and a core roller of closed rolling are designed to prevent the ring from moving up and down during rolling and ensure rolling stability. The inner conical section ring blank is rolled into an asymmetric outer double groove casing ring forging by using the combined driving roller and the core roller of closed rolling. According to the volume change trend of each area during the rolling process, the core roller rolling speed curve and the driving roller speed are designed, so as to ensure that the inner diameter difference between the upper and lower ends of the asymmetric outer double groove casing ring forging is within a reasonable range without increasing the volume of the ring blank.

2. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 1 is characterized in that: The method of performing taper compensation on the inner surface of the ring blank for rolling to obtain the ring blank with inner tapered section is: Assume that the maximum outer diameter of the asymmetric outer double groove casing ring forging is , inner diameter is , height is , the groove depth is , groove radius is , the maximum groove width is , small groove width is The volume of the groove is , the volume after filling the groove is , its own volume is V; The maximum outer diameter of the asymmetric double groove casing ring forging As a reference, determine the outer diameter of the inner conical section ring blank , k is the equivalent rolling ratio; Inner conical section ring blank height Inner surface slope of inner conical section ring blank Inner surface taper of inner conical section ring blank Volume of inner conical section ring blank in, The inner diameter of the small end of the inner conical section ring blank, The inner diameter of the large end of the ring blank with an inner conical section; For , First, the asymmetric outer double groove casing ring forging is divided into five regions along the axial direction from the small end to the large end. The volumes corresponding to the five regions are , , , , The inner diameters of the five regions are , , , , , where the volume and inner diameter of the second and fourth regions are determined by the following formula Then, the inner surface slope of the inner conical section ring blank is obtained by the inner diameter difference between the second area and the fourth area. ,in is the vertical distance between the second area and the fourth area; the taper of the inner surface of the inner conical section ring blank ; According to the above formula, the outer diameter of the ring blank with a known inner conical section , Inner surface taper of inner conical section ring blank , Inner surface slope of inner conical section ring blank , Inner conical section ring blank height Based on the principle of equal volume before and after rolling, the inner diameter of the small end of the inner conical section ring is obtained. , inner diameter of the large end of the inner conical section ring blank ; Among them, the volume of the asymmetric outer double groove casing ring forging is , the volume of the groove part of the asymmetric outer double groove casing ring forging , the volume of the asymmetric outer double groove casing ring forging after filling the groove part .

3. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 2, characterized in that: The equivalent rolling ratio k is 1.3~2.

4. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 1, characterized in that: The method for designing the combined drive roll and core roll of the closed rolling is: Since the shape of the driving roller when the inner conical section ring is rolled to the asymmetric outer double groove casing ring forging must correspond to the cross-sectional shape of the asymmetric outer double groove casing ring forging, the maximum diameter of the driving roller working surface is , minimum diameter And the core roller working surface diameter Determined by the following formula To prevent the ring from axial movement, add upper and lower baffles to the drive roller and increase the cavity height of the drive roller. = + , core roller height mm, is the axial play value, is the height of the asymmetric outer double groove casing ring forging; Cavity width when the driving roller and the core roller are closed ; in, The taper of the inner surface of the ring blank with inner conical section, The maximum outer diameter of the asymmetric outer double groove casing ring forging, The inner diameter of the asymmetric outer double groove casing ring forging is is the groove depth of the asymmetric outer double groove casing ring forging; is the friction angle, , is the friction coefficient; and They are the maximum and minimum closed center distances allowed by the ring rolling machine.

5. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 4, characterized in that: The draft angle of the upper and lower baffles of the driving roller is 1-2°.

6. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 4, characterized in that: Friction coefficient It is 0.1~0.

4.

7. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 1, characterized in that: The method for designing the core roll rolling speed curve and the driving roll speed is: In the process of rolling asymmetric outer double groove casing ring forgings from inner conical ring billet, the volume of the second and fourth regions will decrease sharply when the outer diameter of the ring is rolled from D0 to D1, the volume of the second region will be compensated to the first and third regions, and the volume of the fourth region will be supplemented to the third and fifth regions, showing that the volume of the third region in the middle is the largest. Therefore, the feed speed of the core roller can be linearly increased in the early stage of rolling (0-t1)s, and the outer diameter of the ring is rolled from D1 to D1. k The volume of all regions reaches the maximum value when the ring is rolled to D3. Therefore, in the stage from D1 to D3, i.e. (t2-t3)s, the feed speed of the core roller is set to a fixed value to ensure the smooth rolling of the ring. k In the stage (t3-t4)s, the core roll feed speed is reduced and the rolling is gradually finished; Driving roller speed , is the maximum linear speed of the driving roller; Core roller feed speed satisfy in The outer diameter of the ring is The wall thickness at The outer diameter of the ring is The wall thickness at The outer diameter of the ring is The wall thickness at the time.

8. The process for reducing the inner diameter difference between the upper and lower ends of an asymmetric outer double groove casing ring forging according to claim 7, characterized in that: Maximum linear speed of driving roller Take 0.7~1.4m / s.

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