Method for processing a forged half-axial flow case

Abstract

The application discloses a processing method of a forged half-axial-flow machine case, and comprises the following steps: S1, a cylindrical forged blank is obtained through forging; S2, rough machining is performed on the forged blank; S3, eccentric milling is adopted to sequentially process the outer contour of a large end and the outer contour of a small end to a design size, wherein a boss end face of the forged blank is reserved with a 1mm-2mm allowance, and a longitudinal abutting face of the forged blank is reserved with a 1mm-2mm allowance; S4, heat treatment is performed on the forged blank; S5, rough machining is performed on a flow channel and an inner groove of the forged blank, wherein the flow channel is reserved with a 1mm-2mm allowance, and the inner groove is reserved with a 1mm-2mm allowance; S6, the forged blank is linearly cut into a left half machine case and a right half machine case; and S7, the longitudinal abutting face is machined to the design size, and then the boss end face, the flow channel and the inner groove are machined to the design size, so as to obtain the forged half-axial-flow machine case. Compared with the prior art, the method has small deformation, stable and controllable quality, can meet the design pattern requirement, has a short processing period, and greatly shortens the new machine development period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, in particular, to a forging half-axial casing machining method. BACKGROUND

[0002] In a small and medium-sized aero-engine compressor, the axial casing is a core component, which plays a decisive role in the performance parameters of the aero-engine. The axial casing is a thin-walled part with poor rigidity and easy deformation. Since the rotor blades and stator blades of the compressor are alternately distributed, when the half-axial casing structure is adopted, the compressor rotor blade parts can be assembled into a component, the compressor stator blade parts can be assembled into a component, and the rotor component and the stator component can be assembled together by merging the half-open axial casing, so that the rotor blades and the stator blades are alternately distributed, and the non-adjustable stator blades can be designed as a non-integral ring structure to realize the installation of all axial stage stator blades on one casing, and allow the clearance between the rotor and the stator blades to be checked directly after the aero-engine is assembled by opening the half-axial casing and the stator blades assembled on the half-axial casing, so as to ensure the safety of the aero-engine. This structure layout is simple to assemble, compact in space, and high in reliability, and is widely used in small and medium-sized aero-engines.

[0003] At present, the axial casing blanks produced in batches at this stage are castings, and the machining allowance of the castings is small, and there is a relatively stable machining process. However, due to the complex structure of the axial casing, the period from the casting blank to the stable output of qualified blanks is too long, about 6 months to 1 year and a half; therefore, in the pre-research stage of the engine, in order to shorten the development period, the forged blank is often used to process the finished axial casing, so as to test the feasibility of the engine design in advance. Compared with the casting blank, the production period of the forged blank is very short, but the machining allowance is larger, the deformation of the part is larger during roughing, the machining difficulty is higher, and the forged blank is cylindrical. If the outer boss and the inner flow passage are machined in the conventional circular state during actual machining, the stress release deformation of the part wire-cut half-casing is larger, and the flatness of the two half-casings is poor, which cannot meet the requirements of part combination and sealing (the design requires that the flatness is not greater than 0.03mm), and further precision machining of the longitudinal joint surface is required. After the longitudinal joint surface is precision machined, the deviation of the boss of the combined half-casing from the design theoretical position is large, which cannot meet the design requirements. Therefore, how to reasonably arrange the process to ensure that the deviation of the outer boss of the part from the design theoretical position is minimized after the part is machined, and then ensure the size and position requirements of the subsequent boss is a difficult problem to be solved. SUMMARY

[0004] The application provides a forging half-axial flow machine casing processing method to solve the technical problems of long processing period or high processing difficulty of the existing half-axial flow machine casing.

[0005] According to one aspect of the application, a forging half-axial flow machine casing processing method is provided, comprising the following steps: S1, obtaining a cylindrical forging blank by forging; S2, rough machining the forging blank; S3, sequentially machining the outer contour of the large end and the outer contour of the small end to the design size by eccentric milling, wherein the boss end face of the forging blank is reserved with a 1mm-2mm allowance, and the longitudinal abutting face of the forging blank is reserved with a 1mm-2mm allowance; S4, heat treating the forging blank; S5, rough machining the flow channel and the inner groove of the forging blank, wherein the flow channel is reserved with a 1mm-2mm allowance, and the inner groove is reserved with a 1mm-2mm allowance; S6, linear cutting the forging blank into left and right half machine casings; S7, machining the longitudinal abutting face to the design size, and then machining the boss end face, the flow channel and the inner groove to the design size to obtain the forging half-axial flow machine casing.

[0006] As a further improvement of the above technical solution:

[0007] Further, step S3 specifically comprises the following steps: S31, supporting the large end of the forging blank and pressing the large end mounting edge, and then machining the small end outer contour to the design size by eccentric milling, and in the machining process, reserving the boss end face near the small end of the forging blank with a 1mm-2mm allowance, and reserving the longitudinal abutting face near the small end of the forging blank with a 1mm-2mm allowance; S32, supporting the small end of the forging blank and pressing the small end mounting edge, and then machining the large end outer contour to the design size by eccentric milling, and in the machining process, reserving the boss end face near the large end of the forging blank with a 1mm-2mm allowance, and reserving the longitudinal abutting face near the large end of the forging blank with a 1mm-2mm allowance.

[0008] Further, between step S31 and step S32, there is further a step of marking on the small end outer contour of the forging blank.

[0009] Further, step S2 specifically comprises the following steps: S21, clamping the forging blank to pre-machining the small end of the forging blank, and then machining the inner hole, end face and outer circle near the small end of the forging blank by the maximum profile of the forging blank rotation, and reserving an allowance of at least 3mm; S22, supporting the small end of the forging blank and pressing the small end mounting edge to pre-machining the large end of the forging blank, and then machining the inner hole, end face and outer circle near the large end of the forging blank by the maximum profile of the forging blank rotation, and reserving an allowance of at least 3mm.

[0010] Further, in step S3, the specific steps of eccentric milling are as follows: firstly, rough machining is carried out by using a Φ16mm milling cutter, and a 0.5mm-1mm allowance is reserved, then finishing machining is carried out by using a Φ8mm milling cutter, and finally, a Φ4mm and a Φ2mm milling cutter are used to perform the clean-up of the outer contour corner or the boss connection.

[0011] Further, in step S3, the machining parameters of various milling cutters are as follows: for the Φ16 milling cutter, the linear speed is 80m / s-90m / s, and the feed rate is 200mm / min-230mm / min; for the Φ8 milling cutter, the linear speed is 40m / s-50m / s, and the feed rate is 110mm / min-120mm / min; for the Φ4 milling cutter, the linear speed is 30m / s-40m / s, and the feed rate is 50mm / min-60mm / min; and for the Φ2 milling cutter, the linear speed is 15m / s-20m / s, and the feed rate is 20mm / min-30mm / min.

[0012] Further, in step S7, the specific steps of machining the longitudinal fitting surface to the designed size are as follows: S71, the large end of the forging blank is supported on the milling machine, the large end mounting side reverse surface is pressed tightly, the diagonal surface of the forging blank is aligned, the runout is less than 0.03mm, the small end is then supported, the small end is pressed tightly, and finally, the longitudinal fitting surface is milled and an allowance of 0.05mm-0.1mm is reserved; S72, the large end of the forging blank is supported on the grinding machine, the large end mounting side reverse surface is pressed tightly, the diagonal surface of the forging blank is aligned, the runout is less than 0.03mm, the small end is then supported, the small end is pressed tightly, and finally, the longitudinal fitting surface is ground, and the flatness of the longitudinal fitting surface is ensured to be less than 0.02mm.

[0013] Further, in steps S71 and S72, when the small end and the large end are pressed tightly, the change before and after pressing is checked by using a dial gauge, and the change before and after pressing is ensured to be less than 0.005mm.

[0014] Further, between step S1 and step S2, there is also a step of marking the forging blank.

[0015] Further, between step S2 and step S3, there is also a step of re-marking the forging blank.

[0016] The present application has the following beneficial effects:

[0017] The forging machining method of the half-axial flow casing first obtains a cylindrical forging blank through forging, then rough machines the forging blank, and then processes the outer contour of the large end and the outer contour of the small end to the design size in sequence through eccentric milling, so as to reserve 1mm-2mm allowance for the subsequent longitudinal fitting surface of the cut forging blank, so as to ensure that the boss has the minimum deviation from the design theoretical position after the subsequent allowance of the longitudinal fitting surface is removed, and 1mm-2mm allowance is reserved for the boss end face to eliminate the deviation in the subsequent machining step. After the outer contour of the forging blank is machined in place, the forging blank is heat treated to eliminate the large cutting stress generated by the removal of a large allowance. The machining allowance of the outer contour is the largest, and the machining deformation is the largest, so the outer contour is machined first, and then the flow channel and the inner groove of the forging blank are rough machined, so that the flow channel and the inner groove have sufficient allowance when the outer contour is machined, the part has good rigidity, and the machining deformation is reduced. The flow channel reserves 1mm-2mm allowance, and the inner groove reserves 1mm-2mm allowance, so that when the forging blank is wire cut into left and right two half casings, the wire cutting amount is as small as possible, and the rigidity of the forging blank is ensured, so that the stress release of the cut half forging blank is not too large, thereby affecting the machining of the longitudinal fitting surface and the position of the boss. Finally, the longitudinal fitting surface is machined to the design size, and then the boss end face, the flow channel and the inner groove are machined to the design size, so as to obtain the forging half-axial flow casing. The forging half-axial flow casing obtained by the scheme has small deformation, stable and controllable quality, can meet the design pattern requirements, has short machining cycle, greatly shortens the new machine development cycle, has high practicability, and is suitable for wide promotion and application.

[0018] In addition to the objects, features, and advantages described above, the present application has other objects, features, and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings constituting a part of this application serve to provide a further understanding of the present application, and the illustrative embodiments of the present application and their description serve to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 is a step block diagram of the forging machining method of the half-axial flow casing of the preferred embodiment of the present application;

[0021] Figure 2 is a structural schematic diagram of the forging blank in step S1 of the forging machining method of the half-axial flow casing of the preferred embodiment of the present application;

[0022] Figure 3 is a structural schematic diagram of the forging blank in step S21 of the forging machining method of the half-axial flow casing of the preferred embodiment of the present application;

[0023] Figure 4 is a structure diagram of the forging blank in step S22 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application;

[0024] Figure 5 is a structure diagram of the forging blank in step S3 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application;

[0025] Figure 6 is a structure diagram of the forging blank in step S31 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application;

[0026] Figure 7 is a structure diagram of the forging blank in step S32 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application;

[0027] Figure 8 is a structure diagram of the forging blank in step S5 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application;

[0028] Figure 9 is a structure diagram of the forging blank in step S6 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application;

[0029] Figure 10 is a structure diagram of the forging blank in step S71 of the forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application. DETAILED DESCRIPTION

[0030] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following.

[0031] As shown in the drawings, Figures 1-10 The forging-to-half-axial-flow-casing processing method of the preferred embodiment of the present application comprises the following steps: S1, forging to obtain a cylindrical forging blank; S2, rough machining the forging blank; S3, using eccentric milling to sequentially machine the outer contour of the large end and the outer contour of the small end to the design size, wherein the boss end face of the forging blank is reserved with a 1mm-2mm allowance, and the longitudinal abutting face of the forging blank is reserved with a 1mm-2mm allowance; S4, heat treating the forging blank; S5, rough machining the flow passage and the inner groove of the forging blank, wherein the flow passage is reserved with a 1mm-2mm allowance, and the inner groove is reserved with a 1mm-2mm allowance; S6, wire cutting the forging blank into left and right two half casings; S7, first machining the longitudinal abutting face to the design size, and then machining the boss end face, the flow passage and the inner groove to the design size, to obtain the forging-to-half-axial-flow-casing.

[0032] Specifically, the forging machining method for the half-axial flow case comprises the following steps: firstly, a cylindrical forging blank is obtained by forging; then, rough machining is performed on the forging blank; subsequently, the outer contour of the large end and the outer contour of the small end are sequentially machined to the design size by eccentric milling, so as to reserve 1mm-2mm allowance for the subsequent longitudinal abutting surface of the cut forging blank, thereby ensuring that the boss has the minimum deviation from the design theoretical position after the allowance of the subsequent longitudinal abutting surface is removed, and reserving 1mm-2mm allowance for the boss end face to eliminate the deviation in the subsequent machining step; after the outer contour of the forging blank is machined to the design size, heat treatment is performed on the forging blank to eliminate the large cutting stress caused by the removal of a large allowance; the machining allowance of the outer contour is the largest and the machining deformation is the largest, therefore, the outer contour is machined first, and then the flow passage and the inner groove of the forging blank are machined, so as to ensure that the flow passage and the inner groove have sufficient allowance when the outer contour is machined, the part has good rigidity, and the machining deformation is reduced; the flow passage is reserved with 1mm-2mm allowance, and the inner groove is reserved with 1mm-2mm allowance, so as to minimize the wire cutting amount while ensuring that the forging blank has sufficient rigidity when the forging blank is wire cut into left and right half cases, thereby avoiding that the stress of the cut forging blank is excessively released after being cut into two halves, and affecting the machining of the longitudinal abutting surface and the position of the boss; finally, the longitudinal abutting surface is machined to the design size, and then the boss end face, the flow passage and the inner groove are machined to the design size, so as to obtain the forging half-axial flow case; the forging half-axial flow case obtained by the scheme has small deformation, stable and controllable quality, can meet the design drawing requirements, has a short machining cycle, greatly shortens the new machine development cycle, has high practicability, and is suitable for wide promotion and application.

[0033] As shown in Figures 5-7 In the embodiment, step S3 specifically comprises the following steps: S31, abutting against the large end of the forging blank and pressing the large end mounting edge, and then machining the small end outer contour to the design size by eccentric milling, and reserving 1mm-2mm allowance for the boss end face close to the small end on the forging blank and reserving 1mm-2mm allowance for the longitudinal abutting surface close to the small end on the forging blank during the machining process; S32, abutting against the small end of the forging blank and pressing the small end mounting edge, and then machining the large end outer contour to the design size by eccentric milling, and reserving 1mm-2mm allowance for the boss end face close to the large end on the forging blank and reserving 1mm-2mm allowance for the longitudinal abutting surface close to the large end on the forging blank during the machining process. Specifically, the large end of the forging blank is clamped first to machine the small end outer contour of the forging blank; then, the small end of the forging blank is clamped to machine the small end outer contour of the forging blank, and the machining precision is ensured by the conversion of the machining reference.

[0034] In this embodiment, between step S31 and step S32, there is also a step of marking the small end outer contour of the forging blank. Specifically, after the small end outer contour of the forging blank is machined, marking is performed on the small end outer contour of the forging blank to update the information and avoid confusion.

[0035] As shown in Figure 3 and Figure 4 In this embodiment, step S2 specifically includes the following steps: S21, clamp the forging blank to pre-machining the small end of the forging blank, and then remove the inner hole, end face and outer circle of the forging blank close to the small end with the maximum contour of the forging blank rotation, and reserve at least 3mm allowance; S22, support the small end of the forging blank and press the small end mounting edge to pre-machining the large end of the forging blank, and then remove the inner hole, end face and outer circle of the forging blank close to the large end with the maximum contour of the forging blank rotation, and reserve at least 3mm allowance. Specifically, by pre-machining the large end and small end of the forging blank respectively, a machining reference is provided for subsequent machining, and the forging blank is rough machined to reserve at least 3mm allowance to ensure smooth subsequent machining.

[0036] In this embodiment, in step S3, the specific steps of eccentric milling are as follows: first, rough machining is performed with a Φ16mm milling cutter and 0.5mm-1mm allowance is reserved, then finishing machining is performed with a Φ8mm milling cutter, and finally, a Φ4mm and Φ2mm milling cutter is used to clean the root of the part outer contour corner or boss connection. Specifically, first, the Φ16mm milling cutter is used for rough machining of the forging blank to improve machining efficiency, and 0.5mm-1mm allowance is reserved for finishing machining to avoid excessive deformation during rough machining, which makes subsequent machining impossible, and then the Φ8mm milling cutter is used for finishing machining,

[0037] In this embodiment, in step S3, the machining parameters of various milling cutters are as follows: Φ16 milling cutter: linear speed of 80m / s-90m / s, feed rate of 200mm / min-230mm / min; Φ8 milling cutter: linear speed of 40m / s-50m / s, feed rate of 110mm / min-120mm / min; Φ4 milling cutter: linear speed of 30m / s-40m / s, feed rate of 50mm / min-60mm / min; Φ2 milling cutter: linear speed of 15m / s-20m / s, feed rate of 20mm / min-30mm / min. Specifically, during rough machining, the Φ16 milling cutter uses high linear speed and high feed rate to quickly remove the allowance, and during finishing and cleaning, the speed is reduced to reduce cutting force and thus machining deformation.

[0038] As shown in Figure 10As shown, in this embodiment, in step S7, the specific steps of first processing the longitudinal fitting surface to the design size are as follows: S71, support the large end of the forging blank on a milling machine, and press the back of the large end mounting edge, align the diagonal surface runout of the forging blank to be less than 0.03mm, then provide auxiliary support to the small end, and press the small end, and finally mill the longitudinal fitting surface, and reserve a margin of 0.05 mm-0.1mm; S72, support the large end of the forging blank on a grinding machine, and press the back of the large end mounting edge, align the diagonal surface runout of the forging blank to be less than 0.03mmm, then provide auxiliary support to the small end, and press the small end, and finally grind the longitudinal fitting surface, and ensure that the flatness of the longitudinal fitting surface is less than 0.02mm. Specifically, when clamping the forging blank on the milling machine and grinding machine, the runout of the diagonal surface of the forging blank is aligned to be less than 0.03mm, and the auxiliary support is adjusted to ensure that the small end mounting edge has reliable support, thereby ensuring that the forging blank is reliably clamped, thereby ensuring the processing quality during milling and grinding.

[0039] In this embodiment, in steps S71 and S72, when the small end and the large end are compressed, a dial indicator is used to check the change before and after compression, and the change is ensured to be less than 0.005 mm. Specifically, the dial indicator is used to check the change before and after compression to avoid deformation during processing and compression and to ensure uniformity of the machining allowance removal.

[0040] In this embodiment, between step S1 and step S2, the process further includes the step of marking the forging blank. Specifically, by marking the forging blank, the workpiece type is identified, the processing operation is guided, and the workpiece quality is ensured.

[0041] In this embodiment, the method further includes the step of re-marking the forging blank between step S2 and step S3. Specifically, after the forging blank is rough-machined, the forging blank is re-marked to update the machining information.

[0042] In one embodiment, the specific processing steps of forging a semi-axial flow casing are as follows:

[0043] like Figure 2 As shown, a cylindrical forging blank is obtained by forging, and the forging blank is marked;

[0044] like Figure 3 As shown, the forging blank is clamped to pre-roughen the small end of the forging blank, and then the inner hole, end face and outer circle of the forging blank near the small end are removed by rotating the forging blank with the maximum contour, and at least 3mm margin is reserved;

[0045] like Figure 4As shown, the small end of the forging blank is supported and the small end mounting edge is pressed tightly, so as to pre-roughen the large end of the forging blank, and then the inner hole, end face and outer circle of the forging blank close to the large end are machined and removed with the maximum profile of the forging blank rotation, and at least 3mm allowance is reserved;

[0046] The forging blank is re-marked;

[0047] As shown, Figure 6 the large end of the forging blank is supported and the large end mounting edge is pressed tightly, and then the small end outer contour is machined to the design size by eccentric milling, and in the machining process, the boss end face of the forging blank close to the small end is reserved 1mm-2mm allowance, and the longitudinal abutting surface of the forging blank close to the small end is reserved 1mm-2mm allowance;

[0048] The mark is transferred to the small end outer contour of the forging blank;

[0049] As shown, Figure 7 the small end of the forging blank is supported and the small end mounting edge is pressed tightly, and then the large end outer contour is machined to the design size by eccentric milling, and in the machining process, the boss end face of the forging blank close to the large end is reserved 1mm-2mm allowance, and the longitudinal abutting surface of the forging blank close to the large end is reserved 1mm-2mm allowance;

[0050] The forging blank is heat treated;

[0051] As shown, Figure 8 the large end of the forging blank is supported, and the flow channel and inner groove of the forging blank are roughly machined, wherein the flow channel is reserved 1mm-2mm allowance, and the inner groove is reserved 1mm-2mm allowance;

[0052] As shown, Figure 9 the longitudinal abutting surface is aligned, and the forging blank is wire cut into left and right half machine casings;

[0053] As shown, Figure 10 the large end of the forging blank is supported on the milling machine and the large end mounting edge reverse surface is pressed tightly, the diagonal surface jump of the forging blank is aligned to be less than 0.03mm, then the small end is assisted to support and pressed tightly, and finally the longitudinal abutting surface is milled and processed with 0.05mm-0.1mm allowance reserved;

[0054] the large end of the forging blank is supported on the grinding machine and the large end mounting edge reverse surface is pressed tightly, the diagonal surface jump of the forging blank is aligned to be less than 0.03mm, then the small end is assisted to support and pressed tightly, and finally the longitudinal abutting surface is ground and processed, and the flatness of the longitudinal abutting surface is ensured to be less than 0.02mm;

[0055] The left and right half machine casings are combined by machining the longitudinal abutting surface bolt hole;

[0056] After combination, the milling processing angle and inner circle are used for subsequent alignment;

[0057] The flow channel and stationary blade slot are rough machined and the spraying area is processed to the final state;

[0058] After the left and right half casings are disassembled, spraying and stabilization treatment are carried out;

[0059] The spraying layer of the two half casings is processed after being combined and rough machined;

[0060] The left and right half casings are disassembled, and the large end surface is ground on the abutting surface;

[0061] After the precise bolt hole of the longitudinal abutting surface is processed to the position, the precise hole bolt is replaced after the left and right half casings are combined;

[0062] The two end surfaces, inner flow channel and stationary blade slot are precisely machined to the final size;

[0063] All the bosses, guide vane holes and end surface holes are further machined;

[0064] Finally, the stationary blade stop groove of the abutting surface is processed after being split, and the processing of the half shaft flow casing of the forging is completed.

[0065] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of machining a forged half-axle flow sleeve, characterized in that, It comprises the following steps: S1, forging to obtain a cylindrical forging blank; S2, rough machining of the forging blank; S3, the outer contour of the large end and the outer contour of the small end are sequentially machined to the design size by eccentric milling, wherein the boss end face of the forging blank is reserved 1mm-2mm allowance, and the longitudinal fitting surface of the forging blank is reserved 1mm-2mm allowance; S4, heat treatment of the forging blank; S5, rough machining of the flow channel and the inner groove of the forging blank, wherein the flow channel is reserved 1mm-2mm allowance, and the inner groove is reserved 1mm-2mm allowance; S6, linear cutting of the forging blank into left and right half machine cases; S7, machining the longitudinal fitting surface to the design size, and then machining the boss end face, the flow channel and the inner groove to the design size to obtain the forging half shaft flow machine case; In step S7, the specific steps of machining the longitudinal fitting surface to the design size are as follows: S71, supporting the large end of the forging blank on the milling machine and pressing the large end mounting edge, aligning the diagonal face of the forging blank with a runout of less than 0.03mm, then supporting the small end and pressing the small end, and finally milling the longitudinal fitting surface and reserving 0.05mm-0.1mm allowance; S72, supporting the large end of the forging blank on the grinding machine and pressing the large end mounting edge, aligning the diagonal face of the forging blank with a runout of less than 0.03mm, then supporting the small end and pressing the small end, and finally grinding the longitudinal fitting surface and ensuring that the longitudinal fitting surface flatness is less than 0.02mm.

2. The method of claim 1, wherein the forging is split half-axial flow case. Step S3 specifically comprises the following steps: S31, supporting the large end of the forging blank and pressing the large end mounting edge, and then machining the small end contour to the design size by eccentric milling, and in the process, reserving 1mm-2mm allowance on the boss end face of the forging blank near the small end, and reserving 1mm-2mm allowance on the longitudinal fitting surface of the forging blank near the small end; S32, supporting the small end of the forging blank and pressing the small end mounting edge, and then machining the large end contour to the design size by eccentric milling, and in the process, reserving 1mm-2mm allowance on the boss end face of the forging blank near the large end, and reserving 1mm-2mm allowance on the longitudinal fitting surface of the forging blank near the large end.

3. The method of claim 2 wherein the forging is split half-axial flow case. Between step S31 and step S32, there is also a step: Marking on the small end contour of the forging blank.

4. The method of claim 1, wherein the forging is a half-axial flow case. Step S2 specifically comprises the following steps: S21, clamping the forging blank to pre-roughen the small end of the forging blank, and then removing the inner hole, end face and outer circle near the small end of the forging blank with the maximum profile of the forging blank rotation, and reserving at least 3mm allowance; S22, supporting the small end of the forging blank and pressing the small end mounting edge to pre-roughen the large end of the forging blank, and then removing the inner hole, end face and outer circle near the large end of the forging blank with the maximum profile of the forging blank rotation, and reserving at least 3mm allowance.

5. The method of claim 1, wherein the forging is a half-axial flow case. In step S3, the specific steps of eccentric milling are as follows: First, rough machining is performed using a Φ16 mm milling cutter, and a 0.5 mm-1 mm allowance is reserved, then finishing is performed in place using a Φ8 mm milling cutter, and finally, a Φ4 mm and Φ2 mm milling cutter is used to perform a clean-up on the outer contour corner or boss connection of the part.

6. The method of claim 5 wherein the forging is split half-axial flow case. In step S3, the machining parameters of various milling cutters are as follows: Φ16 milling cutter: linear velocity is 80 m / s-90 m / s, feed rate is 200 mm / min-230 mm / min; Φ8 milling cutter: linear velocity is 40 m / s-50 m / s, feed rate is 110 mm / min-120 mm / min; Φ4 milling cutter: linear velocity is 30 m / s-40 m / s, feed rate is 50 mm / min-60 mm / min; Φ2 milling cutter: linear velocity is 15 m / s-20 m / s, feed rate is 20 mm / min-30 mm / min.

7. The method of claim 1-5, wherein the forging is a half-axial flow case. In steps S71 and S72, when the small end and the large end are pressed, a dial gauge is used to check the change before and after pressing, and it is ensured that the change before and after is less than 0.005 mm.

8. The method of claim 1-5, wherein the forging is a half-axial flow case. Between step S1 and step S2, there is also a step: Marking the forging blank.

9. The method of claim 8 wherein the forging is split half-axial flow case. Between step S2 and step S3, there is also a step: Re-marking the forging blank.

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