Manufacturing method of impeller with ternary system structure

Abstract

The invention discloses a manufacturing method of an impeller of a ternary system structure, and belongs to the technical field of mechanical manufacturing. The impeller comprises a cover disc, a plurality of blades connected with the cover disc and a shaft disc connected with the blades; comprising the following steps: a) providing a cover disc blank and a shaft disc blank, and integrally manufacturing a cover disc and a plurality of blades from the cover disc blank so as to obtain a'cover disc-blade 'integrated piece; b) processing the shaft disc blank into a shaft disc; c) fixedly connecting the'cover disc-blade 'integrated piece with the shaft disc to form a semi-finished impeller; and d) carrying out finish machining on the impeller semi-finished product to obtain the ternary system structure impeller. According to the method, the complex blade profile is integrally milled and formed from the cover disc blank with better rigidity, and the welding procedure is transferred to an interface with a relatively simple geometrical shape between the blade and the shaft disc, so that the processing deformation risk of the thin-wall cover disc is fundamentally avoided, the welding quality and the control precision are remarkably improved, and the production cost is reduced. And meanwhile, the processing period is greatly shortened, and the manufacturing cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mechanical manufacturing, in particular to a manufacturing method of a three-element structure impeller. BACKGROUND

[0002] The impeller is the core component of fluid machinery for energy conversion, and its performance directly determines the efficiency and running stability of the whole machine. Especially the three-element structure impeller with complex three-dimensional twisted blades is widely used in high-performance compressors and other equipment due to its excellent aerodynamic performance. However, its complex geometry, especially the severe twisting of the blade profile in the narrow flow channel, brings great challenges to manufacturing.

[0003] Currently, there are two mainstream manufacturing processes for such narrow flow channel three-element impellers in the industry. The first one is "cover plate slotting and welding method", that is, the cover plate, shaft plate and each independent blade of the impeller are manufactured respectively, then the flow channel slot for accommodating the blades is milled on the relatively thin cover plate, and finally the blades are placed in the slot and welded with the cover plate and the shaft plate. The main defect is that the cover plate is relatively thin itself to meet the aerodynamic design requirements, and a large amount of material is milled on it to form slots, which further destroys the structural integrity and greatly reduces its own stiffness. In the subsequent complex welding process, the huge heat input and welding stress can easily cause uncontrollable distortion of the cover plate, seriously affecting the final size accuracy and flow channel shape of the impeller, resulting in low product qualification rate.

[0004] The second one is "whole electric spark machining method", that is, a whole piece of forging is used to etch complex blades and flow channels inside the material by electric spark machining (EDM). This method can accurately realize the designed shape, but its fatal defect is that the metal removal efficiency is extremely low, the processing cycle is very long, and the equipment investment and operating energy consumption are huge, resulting in extremely high manufacturing cost, which is difficult to meet the requirements of economic production.

[0005] In summary, how to provide a manufacturing method that can guarantee the manufacturing precision and quality of the three-element structure impeller, effectively control the manufacturing cost, shorten the production cycle, and at the same time avoid the risk of deformation of key components in the processing process, is an important technical problem currently faced by the field. SUMMARY

[0006] Therefore, the present application provides a manufacturing method of a three-element structure impeller. The main purpose is to solve the technical problem of guaranteeing the manufacturing precision and quality of the three-element structure impeller while effectively controlling the manufacturing cost, shortening the production cycle, and at the same time avoiding the risk of deformation of key components in the processing process.

[0007] According to the present application, a manufacturing method of a ternary structure impeller is provided, the impeller comprising a cover disc, a plurality of blades connected with the cover disc, and a shaft disc connected with the plurality of blades; the method comprising the following steps: a) providing a cover disc blank and a shaft disc blank to integrally manufacture the cover disc and the plurality of blades from the cover disc blank, thereby obtaining a "cover disc-blade" integrated piece; b) processing the shaft disc blank into the shaft disc; c) fixedly connecting the "cover disc-blade" integrated piece with the shaft disc to form an impeller semi-finished product; d) finishing the impeller semi-finished product to obtain the ternary structure impeller.

[0008] Further, after steps b) and c) and before step d), the method further comprises a step c2): performing pre-welding structural processing on the "cover disc-blade" integrated piece and the shaft disc, machining a concave positioning stop on the "cover disc-blade" integrated piece; and machining a convex positioning stop on the shaft disc which matches the concave positioning stop, while machining a welding groove on the side of the shaft disc away from the convex positioning stop, the welding groove having a groove bottom thickness of 1mm to 1.3mm, a groove bottom width which is 0.5mm larger than the width of the blade, and a groove bottom length which is equivalent to the length of the blade; and in step c), the "cover disc-blade" integrated piece and the shaft disc are positioned and spliced through the matching of the concave positioning stop and the convex positioning stop, and then fixedly connected.

[0009] Further, before step a), the method further comprises: rough machining the cover disc blank and the shaft disc blank; and performing preliminary heat treatment on the rough machined cover disc blank and shaft disc blank.

[0010] Further, in the step of rough machining, the machining size of the cover disc blank satisfies: cover disc blank side rough machining outer diameter D11=D+A; cover disc blank side rough machining inner hole diameter d1=d-B; wherein D is the maximum outer circle diameter of the impeller, d is the inner hole diameter of the cover disc side of the impeller, A has a value range of 34mm to 40mm, and B has a value range of 20mm to 26mm.

[0011] Further, in steps b) and c), the method further comprises semi-finishing the cover disc blank and the shaft disc blank, the step of semi-finishing at least comprising: performing non-destructive testing on the cover disc blank and the shaft disc blank; and cutting a mechanical property test ring from the cover disc blank and the shaft disc blank which pass the non-destructive testing.

[0012] Further, in the step of semi-finishing the cover disc blank, the machining size satisfies: The semi-finished outer diameter D31 is equal to D+C, wherein C is in the range of 22mm-26mm, and D is the maximum outer diameter of the impeller; The inlet collar diameter D2 of the cover disc blank semi-finished product satisfies (D2-d) / 2 is greater than or equal to 30mm, and the outer diameter direction allowance b of the inlet collar is greater than or equal to 10mm, and the thickness direction allowance a of the inlet collar of the cover disc semi-finished product is in the range of 5mm-8mm.

[0013] Further, in step c), the cover disc-blade integrated piece and the shaft disc are fixedly connected by adopting the process of firstly performing tungsten electrode argon arc welding self-welding without filling wire, and then performing filler welding by electrode arc welding.

[0014] Further, before the cover disc-blade integrated piece and the shaft disc are welded in step c), the blade of the cover disc-blade integrated piece corresponds to the groove bottom of the welding groove of the shaft disc, one blade corresponds to one groove bottom, and the gap of the blade groove bottom is less than or equal to 0.5mm.

[0015] Further, after step c) and before step d), the method further comprises step c2): a step of performing at least one heat treatment on the impeller semi-finished product, and the heat treatment comprises at least one of stress relief treatment and final heat treatment.

[0016] Further, before the final heat treatment, the method further comprises a step of rough machining the impeller semi-finished product before heat treatment, and the machining size satisfies: the maximum outer diameter D5 of the impeller before heat treatment is equal to D+Y; D is the maximum outer diameter of the impeller, the thickness allowance c3 of the shaft disc side hub seat side is in the range of 4-6mm, and Y is in the range of 10mm-16mm.

[0017] The application provides a manufacturing method of a three-element structure impeller, and the cover disc and the blade are integrally formed by a cover disc blank, so that the thin cover disc is no longer slotted, but the blade is milled from a thick cover disc blank, the structural integrity and high rigidity of the cover disc itself are maintained, all complex three-dimensional surfaces of the blade are ensured by high-precision numerical control milling, cover disc body deformation caused by welding heat input is avoided, the surface precision of the most critical side of the impeller flow channel is ensured, the risk of cover disc deformation is fundamentally avoided, and product precision is improved.

[0018] In addition, the welding process is arranged between the cover disc-blade integrated piece and the shaft disc, so that the welding quality and controllability are improved. Specifically, the geometric distortion of the ternary blade is mainly concentrated in the area close to the cover disc, and the blade root profile close to the shaft disc is relatively flat and close to a two-dimensional plane. The welding joint is arranged in the relatively simple geometric area, which greatly reduces the difficulty of three-dimensional control in the welding process, effectively avoids quality defects such as irregular deformation in the flow channel, overall shrinkage and welding cracks in the traditional process. Finally, the high-efficiency numerical control milling process is adopted, and compared with the low-efficiency electric spark processing, the metal removal rate is improved by an order of magnitude, so that the manufacturing period is greatly shortened, and the energy consumption and equipment use cost are significantly reduced.

[0019] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which are part of the present application, serve to provide a further understanding of the present application, and the schematic embodiments of the present application and their descriptions serve to explain the present application, but do not constitute an improper limitation on the present application. Obviously, the drawings in the following description are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] In the drawings: Figure 1 A flow chart of a manufacturing method of a ternary structure impeller provided by an embodiment of the present application is shown; Figure 2 A front view structural schematic diagram of a ternary structure impeller provided by an embodiment of the present application is shown; Figure 3 A top view of a ternary structure impeller provided by an embodiment of the present application is shown; Figure 4 A structural schematic diagram of a cover disc blank after rough machining provided by an embodiment of the present application is shown; Figure 5 A structural schematic diagram of a shaft disc blank after rough machining provided by an embodiment of the present application is shown; Figure 6 A structural schematic diagram of a cover disc blank after semi-finishing machining provided by an embodiment of the present application is shown; Figure 7 A structural schematic diagram of a shaft disc blank after semi-finishing machining provided by an embodiment of the present application is shown; Figure 8 A pre-welding structural schematic diagram of a cover disc-blade integrated piece provided by an embodiment of the present application is shown; Figure 9 A schematic diagram of the pre-weld structure of the shaft disc provided for the embodiment of the present application; Figure 10 A schematic diagram of the welding joint between the "cover disc-blade" integrated piece and the shaft disc provided for the embodiment of the present application; Figure 11 A schematic diagram of the "cover disc-blade" integrated piece after splicing with the shaft disc provided for the embodiment of the present application; Figure 12 A schematic diagram of the rough machining of the impeller before welding and heat treatment provided for the embodiment of the present application.

[0022] Reference signs: 1, cover disc; 2, multiple blades; 3, shaft disc; H, the actual maximum thickness of the cover disc side of the impeller; D, the maximum outer diameter of the impeller; d, the inner hole diameter of the cover disc side of the impeller; φ, the inner hole diameter of the shaft disc side of the impeller; H1, the thickness of the cover disc blank during rough machining; D11, the outer diameter of the cover disc blank during rough machining; d1, the inner hole diameter of the cover disc blank during rough machining; H2, the thickness of the shaft disc blank during rough machining; D12, the outer diameter of the shaft disc blank during rough machining; φ1, the inner hole diameter of the shaft disc side of the impeller during rough machining; H3, the height of the inlet ring of the cover disc blank during semi-finishing machining; H4, the thickness of the outlet side of the cover disc blank during semi-finishing machining; D2, the diameter of the inlet ring of the cover disc blank during semi-finishing machining; D31, the outer diameter of the cover disc blank during semi-finishing machining; D32, the outer diameter of the shaft disc blank during semi-finishing machining; S1, the length of the straight line beside the inlet ring of the cover disc of the impeller during semi-finishing machining; S2, the length of the straight line of the outlet side of the cover disc of the impeller during semi-finishing machining; a, the thickness direction allowance of the inlet ring of the cover disc of the impeller during semi-finishing machining; b, the outer diameter direction allowance of the inlet ring of the cover disc of the impeller during semi-finishing machining; c1, the thickness allowance of the top side of the hub of the shaft disc of the impeller during semi-finishing machining; c2, the thickness allowance of the bottom side of the hub of the shaft disc of the impeller during semi-finishing machining; H5, the height of the convex positioning stop of the shaft disc of the impeller during semi-finishing machining; H6, the height of the concave positioning stop of the cover disc side of the impeller before welding; D4, the maximum outer diameter of the concave positioning stop of the cover disc side of the impeller before welding; H7, the height of the convex positioning stop of the shaft disc side of the impeller before welding; K, the thickness of the groove bottom of the shaft disc of the impeller before welding; α, the outer side angle of the outer side of the shaft disc of the impeller before welding; H8, the thickness of the outlet of the shaft disc side of the impeller before welding; D5, the maximum outer diameter of the impeller before heat treatment; H9, the thickness of the outlet of the shaft disc side of the impeller before heat treatment; C3, the thickness allowance of the hub seat side of the shaft disc of the impeller before heat treatment.

[0023] It should be noted that these drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0024] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to explain the present application, but are not used to limit the scope of the present application.

[0025] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0026] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] Embodiments The preferred embodiments of the present application will be described in detail below with reference to the drawings. The present embodiments are intended to explain the present application, not to limit it.

[0028] As Figures 1-12 shown, a manufacturing method of a ternary structure impeller, the impeller comprising a cover disc 1, a plurality of blades 2 connected with the cover disc 1, and a shaft disc 3 connected with the plurality of blades 2; The method comprises the following steps: a) preparation and rough machining of raw materials: first, according to the design requirements of the impeller, a cover disc blank and a shaft disc blank are provided, so as to integrally form the cover disc 1 and the plurality of blades 2 from the cover disc blank, thereby obtaining a "cover disc-blade" integrated piece; b) processing the shaft disc blank into the shaft disc 3; c) fixedly connecting the "cover disc-blade" integrated piece with the shaft disc 3 to form an impeller semi-finished product; d) finishing the impeller semi-finished product to obtain the ternary structure impeller.

[0029] In the present embodiment, after steps b) and c) and before step d), a step c2) of pre-welding structure machining of the "cover disc-blade" integrated piece and the shaft disc 3 is further included, and a concave positioning stop H6 is machined on the "cover disc-blade" integrated piece; and a convex positioning stop H7 matched with the concave positioning stop H6 is machined on the shaft disc 3, and a welding groove is machined on the side of the shaft disc 3 away from the convex positioning stop H7, the groove bottom thickness of the welding groove is 1mm to 1.3mm, the groove bottom width of the welding groove is 0.5mm larger than the width of the blade, and the groove bottom length of the welding groove is equivalent to the length of the blade; In step c), the two are positioned and spliced by the cooperation of the concave positioning stop H6 and the convex positioning stop H7, and then fixedly connected.

[0030] In a feasible implementation, before step a), the method further comprises: rough machining the cover disc blank and the shaft disc blank; and Pre-treatment is performed on the cover disc blank and the shaft disc blank after rough machining.

[0031] In the step of rough machining, the machining size of the rough machining of the cover disc of the impeller meets: the rough machining outer diameter D11 of the cover disc blank side is D+A; the inner hole d1 of the rough machining of the cover disc of the impeller is d-B; wherein D is the maximum outer diameter of the impeller, d is the designed inner hole size diameter of the cover disc side of the impeller, the value range of A is 34mm to 40mm, and the value range of B is 20mm to 26mm; the thickness H1 of the cover disc blank during rough machining specifically meets: when the maximum thickness H of the actual cover disc side of the impeller plus 5mm to 8mm is less than 50mm, the width of the blade is increased by 60mm to 68mm; when the maximum thickness H of the actual cover disc side of the impeller plus 5mm to 8mm is greater than 50mm, the sum of the width of the blade and the thickness of the cover disc is increased by 15mm to 24mm. The rough machining outer diameter D12 of the shaft disc blank side is D+A, and the value range of A is 34mm to 40mm; the rough machining outer diameter D11 of the cover disc blank is the same as the rough machining outer diameter D12 of the shaft disc blank, and the inner hole size diameter φ1 of the rough machining of the shaft disc of the impeller is φ-20mm~26 mm, wherein φ is the inner hole diameter of the shaft disc of the impeller.

[0032] The thickness H2 of the shaft disc blank during rough machining is increased by 21mm~34 mm. The cover disc blank and the shaft disc blank after rough machining are pre-treated. For example, FV520(B) steel, 17-4PH steel, ASTM A705-630 steel, etc. are subjected to solid solution treatment+adjustment treatment+overaging treatment or solid solution treatment+aging treatment, etc.; KMN steel, X3CrNiMo134 steel, ASTM A182 F22, ASTM A182 F6NM steel, etc. are subjected to normalizing treatment+tempering treatment, etc. The cover disc and the shaft disc after pre-treatment are subjected to ultrasonic flaw detection, and the test ring is cut after the ultrasonic detection is qualified.

[0033] In the embodiment, in steps b) and c), the cover disc blank and the shaft disc blank are also subjected to semi-finishing, which at least includes: subjecting the cover disc blank and the shaft disc blank to non-destructive testing; and cutting a mechanical performance test ring from the cover disc blank and the shaft disc blank that pass the non-destructive testing.

[0034] In the embodiment, in the step of subjecting the cover disc blank to semi-finishing, the machining dimensions satisfy: the value range of the height H3 of the inlet ring during semi-finishing of the cover disc blank is 20 mm to 30 mm; the value range of the thickness H4 of the outlet side during semi-finishing of the cover disc blank is the blade width plus 25 mm to 35 mm; the semi-finishing outer diameter D31 of the cover disc blank is D+C, D is the maximum outer diameter of the impeller, and the value range of C is 22 mm to 26 mm; and the diameter D2 of the inlet ring during semi-finishing of the cover disc blank satisfies, in principle, that (D2-d) / 2 is greater than or equal to 30 mm, and the outer diameter direction allowance b of the ring is greater than or equal to 10 mm, and the value range of the thickness direction allowance a of the inlet ring during semi-finishing of the cover disc blank is 5 mm to 8 mm. In addition, the value range of S1 is 30 mm to 50 mm, S1 is the length of the straight line beside the inlet ring during semi-finishing of the cover disc, and the value range of S2 is 20 mm to 40 mm, S2 is the length of the straight line on the outlet side during semi-finishing of the cover disc, and the straight line directly connecting S1 and S2 can be directly connected.

[0035] In the embodiment, in the step of subjecting the shaft disc blank to semi-finishing, the machining dimensions satisfy: D32=D+C, the semi-finishing outer diameter D32 of the shaft disc blank is the same as the semi-finishing outer diameter D31 of the cover disc blank; in addition, the value range of C is 22 mm to 26 mm, c1 is the thickness allowance of the hub top side during semi-finishing of the shaft disc, the value range of c1 is 5 mm to 8 mm, c2 is the thickness allowance of the hub base side during semi-finishing of the shaft disc, the value range of c2 is 7 mm to 10 mm, the height H5 of the convex positioning stopper during semi-finishing of the shaft disc is the blade width plus 4 to 6, the hub base side of the shaft disc is kept horizontal, and the allowance has the size of c2; and the uniform allowance is 5 mm to 8 mm at other positions based on the design requirement.

[0036] In a feasible embodiment, the cover disc and the shaft disc of the impeller are subjected to structure machining before welding, and specifically, the method specifically includes: I. machining the cover disc after semi-finishing, the value range of H6 is 4 mm to 6 mm, H6 is the height of the convex positioning stopper during semi-finishing of the shaft disc, D4=D31-(8 to 12) mm, D4 is the maximum outer diameter of the concave positioning stopper of the structure on the cover disc side before welding, and the inner hole diameter d of the cover disc side of the impeller is machined to the design size.

[0037] II. The structure processing before the shaft disc welding, specifically comprising: processing the shaft disc after half-finishing, the value range of the convex positioning stop S4 of the shaft disc processing is 4mm-6mm; the value range of the height H7 of the convex positioning stop of the structure before the impeller shaft disc side welding is the blade width plus 4mm-6mm; the value range of the outlet thickness H8 of the structure before the impeller shaft disc side welding is 9mm-12mm; the value range of the groove bottom thickness K of the structure before the impeller shaft disc welding is 1.0mm-1.3mm; the thickness direction allowance a of the inlet ring of the impeller cover disc during the half-finishing is 3°, and when the design requirement a is greater than or equal to 3°, a is kept consistent with the design requirement.

[0038] III. Splicing the cover disc and the shaft disc of the impeller into a "cover disc-blade" integrated piece: the concave positioning stop H6 of the cover disc is spliced with the convex positioning stop H7 of the shaft disc, and the two are fixed by full welding.

[0039] IV. Impeller welding: in step c), the "cover disc-blade" integrated piece and the shaft disc 3 are fixedly connected by adopting the process of first performing the tungsten argon arc welding self-fusion welding without filling wire, and then performing the electrode arc welding filling welding.

[0040] V. Impeller stress relief: after the impeller welding, stress relief treatment is performed to eliminate the internal stress in the welding process.

[0041] VI. The rough machining before the heat treatment of the impeller: the maximum outer diameter D5 of the structure before the heat treatment of the impeller is D+Y, wherein the value range of Y is 10mm-16mm; the value range of the outlet thickness H9 of the structure before the heat treatment of the impeller shaft disc side is 7mm-9mm; the value range of the hub seat side thickness allowance c3 of the structure before the heat treatment of the impeller shaft disc side is 4mm-6mm; the outside angle a of the outside side of the structure before the welding is consistent with the angle of the structure before the welding.

[0042] VII. The impeller and the cover disc and the shaft disc are subjected to heat treatment in the same furnace: after step c) and before step d), step c2) of at least once heat treatment of the impeller semi-finished product is further included, and the heat treatment includes at least one of stress relief treatment and final heat treatment. Specifically, for example: solid solution treatment + adjustment treatment + overaging treatment or adjustment treatment + aging treatment are performed on FV520(B) steel, 17-4PH steel, ASTM A705-630 steel, etc.; quenching treatment + tempering treatment are performed on KMN steel, X3CrNiMo134 steel, ASTM A182 F22, ASTM A182 F6NM steel, etc.

[0043] VIII. Finishing the impeller, and the impeller manufacturing is completed.

[0044] In the present embodiment, before the "cover disc - blade" integrated piece is welded with the shaft disc 3 in the step c), the blades of the "cover disc - blade" integrated piece correspond to the groove bottoms of the welding grooves of the shaft disc 3, one blade corresponds to one groove bottom, and the gap between the blade and the groove bottom is less than or equal to 0.5 mm.

[0045] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above-mentioned technical content with the above-mentioned prompt without departing from the technical solution of the present application, and equivalent embodiments with equivalent changes are equivalent. The embodiments in the above-mentioned embodiments can be further combined or replaced, but as long as it does not deviate from the technical solution of the present application, any simple modification, equivalent change and modification of the above-mentioned embodiments according to the technical essence of the present application are still within the scope of the present application.

Claims

1. A method for manufacturing a ternary impeller, characterized in that, The impeller includes a cover plate (1), a plurality of blades (2) connected to the cover plate (1), and a shaft plate (3) connected to the plurality of blades (2). The method includes the following steps: a) providing a cover plate blank and a shaft plate blank to integrally manufacture the cover plate (1) and the plurality of blades (2) from the cover plate blank, thereby obtaining a "cover plate-blade" assembly; b) The shaft blank is processed into the shaft (3); c) The "cover plate-blade" assembly is fixedly connected to the shaft plate (3) to form a semi-finished impeller; d) The impeller semi-finished product is precision machined to obtain the ternary structure impeller.

2. The manufacturing method of the ternary impeller according to claim 1, characterized in that, After step b) and step c) and before step d), step c2 is also included: pre-welding structural processing is performed on the "cover plate-blade" assembly and the shaft plate (3), and a concave positioning stop (H6) is machined on the "cover plate-blade" assembly. A convex positioning stop (H7) that matches the concave positioning stop (H6) is machined on the shaft disk (3). At the same time, a welding groove is machined on the side of the shaft disk (3) away from the convex positioning stop (H7). The bottom thickness of the welding groove is 1mm to 1.3mm, the bottom width of the welding groove is 0.5mm larger than the width of the blade, and the bottom length of the welding groove is equivalent to the blade length. In step c), the two are positioned and spliced ​​by the cooperation of the concave positioning stop (H6) and the convex positioning stop (H7) before being fixedly connected.

3. The manufacturing method of the ternary impeller according to claim 2, characterized in that, Prior to step a), the method further includes: rough machining the cover plate blank and the shaft plate blank; and performing a preheat treatment on the rough-machined cover plate blank and the shaft plate blank.

4. The manufacturing method of the ternary impeller according to claim 3, characterized in that, In the rough machining step, the machining dimensions of the cover plate blank satisfy: The rough-machined outer diameter of the cover plate blank is D11 = D + A; The inner diameter d1 = dB of the rough-machined inner hole on the side of the cover plate blank; Where D is the maximum outer diameter of the impeller, d is the inner diameter of the impeller cover plate, A ranges from 34mm to 40mm, and B ranges from 20mm to 26mm.

5. The manufacturing method of the ternary impeller according to claim 4, characterized in that, In steps b) and c), the process further includes semi-finishing the cover plate blank and the shaft plate blank, wherein the semi-finishing step includes at least: performing non-destructive testing on the cover plate blank and the shaft plate blank; Mechanical performance test rings are cut from the cover plate blank and the shaft plate blank that have passed non-destructive testing.

6. The manufacturing method of the ternary impeller according to claim 5, characterized in that, In the semi-finishing step of the cover plate blank, the machining dimensions satisfy: The semi-finished outer diameter D31 = D + C, where C ranges from 22mm to 26mm, and D is the maximum outer diameter of the impeller. The diameter D2 of the inlet ring of the semi-finished cover plate blank satisfies (D2-d) / 2 greater than or equal to 30mm, and the allowance b in the outer diameter direction of the ring is greater than or equal to 10mm, while the allowance a in the thickness direction of the ring is in the range of 5mm-8mm.

7. The manufacturing method of the ternary impeller according to claim 1, characterized in that, In step c), the process of first performing tungsten inert gas welding (TIG) without filler wire and then performing shielded metal arc welding (SMAW) to fix the "cover plate-blade" assembly to the shaft plate (3).

8. The manufacturing method of the ternary impeller according to claim 7, characterized in that, Before the "cover plate-blade" assembly is welded to the shaft plate (3) in step c), the blades of the "cover plate-blade" assembly correspond to the bottom of the welding groove of the shaft plate (3), with one blade corresponding to one groove bottom, and the gap between the blade groove bottom is less than or equal to 0.5mm.

9. The manufacturing method of the ternary impeller according to claim 4, characterized in that, After step c) and before step d), step c2) is also included: a step of performing at least one heat treatment on the impeller semi-finished product, the heat treatment including at least one of stress relief treatment and final heat treatment.

10. The manufacturing method of the ternary impeller according to claim 9, characterized in that, Prior to the final heat treatment, the impeller semi-finished product is further subjected to a rough machining step before heat treatment, wherein the machining dimensions satisfy the following: The maximum outer diameter of the impeller before heat treatment is D5 = D + Y; D is the maximum outer diameter of the impeller, the thickness allowance c3 on the shaft disk side and hub seat side ranges from 4 to 6 mm, and the value of Y ranges from 10 mm to 16 mm.

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