A processing technology for vertical tree-shaped blade root moving blade

Abstract

The present invention relates to a processing technology for longitudinal tree-shaped blade root moving blades, which is characterized by: the specific processing technology is as follows: when the blank of the longitudinal tree-shaped blade root moving blade is forged, the blade root tooth structure is not forged, so as to prevent the blade root part of the blank forged by using a toothed forging die from being easily misaligned; in subsequent processing, the wire cutting method is first used to cut the mold line, and the time consumed by the wire cutting method and the time consumed by subsequent milling can still save a long time compared with the time consumed by forging a blank with a large processing allowance and a tooth shape for processing, thereby avoiding the problem of consuming a large number of alloy tool heads and occupying a large amount of machine tool working hours, realizing the rapid processing of the longitudinal tree-shaped blade root moving blades and improving the processing efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of machining longitudinal tree-shaped blade roots and moving blades, and in particular to a machining process for longitudinal tree-shaped blade roots and moving blades. Background Art

[0002] Longitudinal tree-shaped blade root moving blades are commonly used in impeller levels with relatively large loads. The blank of this type of moving blade is 440mm, and the inner radial surfaces of the blade root and the blade crown have high and low surfaces, and are beveled to strengthen the steam outlet edge of the blade; due to the relatively complex shape; the common processing technology uses the blank to forge the initial form and then perform milling. In the common blank forging, the longitudinal tree-shaped blade root is forged directly from the forging die. This forged structure does not need to use wire cutting to cut the tooth shape later, and can be directly processed by rough milling and fine milling; however, this structure has some problems. On the one hand, the tooth structure produced by forging has a large offset, which is not conducive to overall processing; on the other hand, the tooth structure produced by forging requires a large processing allowance to ensure subsequent milling, which results in a lot of time required for milling. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a longitudinal tree-shaped blade root moving blade processing technology, which can solve the problem that the tooth structure in the general longitudinal tree-shaped blade root moving blade processing is directly forged, there is a large amount of misalignment and subsequent milling requires a lot of time for processing.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a longitudinal tree-shaped blade root moving blade processing technology, the innovation of which is: the specific processing technology is as follows:

[0005] S1: Forming of pre-forgings: high chromium alloy steel is used to cast the pre-forgings of the blade root and moving blades to be forged;

[0006] S2: Precision forging of blade roots and moving blades: Place the pre-forged parts into the precision forging die, forge them into shape through the precision forging die, take out the precision forging parts after forming and remove the flash; the surface of the precision forging parts is not allowed to have folds, cracks, pits and inclusions. Defects generated after forging can be removed by grinding, and the grinding depth is not allowed to exceed 1 / 2 of the actual margin, and the width-to-depth ratio of the grinding part is not less than 6:1;

[0007] S3: Determine the center point: Determine the center at both ends of the precision forging and drill the ejector hole at the center point, where the blade crown end face is a single ejector hole and the blade root end face is a three-ejector hole; and stamp the steel stamp > symbol on both end faces of the precision forging, and the opening direction is the steam outlet edge;

[0008] S4: Milling of precision forgings: The precision forgings with the ejector holes drilled are placed on a four-axis machining center using an ejector fixture for milling. The clamping step at the process clamping head is milled by a finger-shaped milling cutter. The milling machine is positioned through the center ejector hole of the process clamp and clamps the clamping step at the process clamping head, reserving the length of the end size to be processed.

[0009] S4.1: Rough milling: Firstly, rough mill the steam inlet and outlet sides of the blade root and the shroud, rough mill the inner and back arc surfaces of the assembly; rough mill the inner and back arc surfaces of the steam channel and the root crown transition; at the same time, mill out the process datum of the blade root;

[0010] S4.2: Processing of blade root tooth shape: Use wire cutting to cut the blade root tooth shape at the blade root part, and use wire cutting to cut the total length of the blade crown; use fine milling to mill the blade root end face and blade root tooth shape;

[0011] S4.3: Radial surface machining: Use fine milling to mill out the inner radial surface and inner bevel angle. The verticality of the inner radial surface to the steam outlet side is ≤0.02, and the angle difference with the back plane is ≤0.02; finally, fine mill the back radial surface;

[0012] S4.4: Steam duct polishing: Polish the inner arc line, back arc line and transition of the steam duct, and measure the guide vane assembly by using the steam duct line gauge, line template and arc surface guide vane assembly total length gauge; the polishing pattern should be in the same direction as the airflow direction, and the inlet and outlet edges should not be burnt and should not be polished into a knife edge;

[0013] S4.5: Process clamping end face cutting: After processing to the designed size, the end face is clamped by wire cutting process. The processed surface should not be damaged. The processing is completed.

[0014] Furthermore, in the S2: precision forging of blade roots and moving blades, the lateral offset and longitudinal offset of the precision forgings shall not be greater than 1 mm, and the residual flash of the precision forgings shall not be greater than 2 mm.

[0015] The advantages of the present invention are:

[0016] 1) In the present invention, the blade root tooth structure is not forged during the forging of the blank of the longitudinal tree-shaped blade root moving blade, so as to prevent the blade root part of the blank forged by the toothed forging die from being easily misaligned; in the subsequent processing, the wire cutting method is first used to cut the mold line. The time consumed by the wire cutting method and the time consumed by the subsequent milling can still save a long time compared with the processing of the blank with a large machining allowance and tooth shape, avoiding the problem of consuming a large number of alloy cutter heads and occupying a large amount of machine tool working hours, realizing the rapid processing of the longitudinal tree-shaped blade root moving blade, and improving the processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0018] Figure 1 The present invention is a flowchart of the processing technology of a longitudinal tree-shaped blade root moving blade.

[0019] Figure 2 This is a diagram of the state of a forged billet of a longitudinal tree-shaped blade root moving blade of the present invention.

[0020] Figure 3 This is a diagram of the state of a longitudinal tree-shaped blade root moving blade of the present invention before processing and forming.

[0021] Figure 4 This is a diagram of the state of a longitudinal tree-shaped blade root moving blade after processing and forming according to the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0026] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0027] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] like Figures 1 to 4 A processing technology for a longitudinal tree-shaped blade root moving blade is shown, and the specific processing technology is as follows:

[0029] S1: Forming of pre-forgings: high chromium alloy steel is used to cast the pre-forgings of the blade root and moving blades to be forged;

[0030] S2: Precision forging of blade roots and moving blades: Place the pre-forged parts into the precision forging die, forge them into shape through the precision forging die, take out the precision forging parts after forming and remove the flash; the surface of the precision forging parts is not allowed to have folds, cracks, pits and inclusions. Defects generated after forging can be removed by grinding, and the grinding depth is not allowed to exceed 1 / 2 of the actual margin, and the width-to-depth ratio of the grinding part is not less than 6:1;

[0031] S3: Determine the center point: Determine the center at both ends of the precision forging and drill the ejector hole at the center point, where the blade crown end face is a single ejector hole and the blade root end face is a three-ejector hole; and stamp the steel stamp > symbol on both end faces of the precision forging, and the opening direction is the steam outlet edge;

[0032] S4: Milling of precision forgings: The precision forgings with the ejector holes drilled are placed on a four-axis machining center using an ejector fixture for milling. The clamping step at the process clamping head is milled by a finger-shaped milling cutter. The milling machine is positioned through the center ejector hole of the process clamp and clamps the clamping step at the process clamping head, reserving the length of the end size to be processed.

[0033] S4.1: Rough milling: Firstly, rough mill the steam inlet and outlet sides of the blade root and the shroud, rough mill the inner and back arc surfaces of the assembly; rough mill the inner and back arc surfaces of the steam channel and the root crown transition; at the same time, mill out the process datum of the blade root;

[0034] S4.2: Processing of blade root tooth shape: Use wire cutting to cut the blade root tooth shape at the blade root part, and use wire cutting to cut the total length of the blade crown; use fine milling to mill the blade root end face and blade root tooth shape;

[0035] S4.3: Radial surface machining: Use fine milling to mill out the inner radial surface and inner bevel angle. The verticality of the inner radial surface to the steam outlet side is ≤0.02, and the angle difference with the back plane is ≤0.02; finally, fine mill the back radial surface;

[0036] S4.4: Steam duct polishing: Polish the inner arc line, back arc line and transition of the steam duct, and measure the guide vane assembly by using the steam duct line gauge, line template and arc surface guide vane assembly total length gauge; the polishing pattern should be in the same direction as the airflow direction, and the inlet and outlet edges should not be burnt and should not be polished into a knife edge;

[0037] S4.5: Process clamping end face cutting: After processing to the designed size, the end face is clamped by wire cutting process. The processed surface should not be damaged. The processing is completed.

[0038] S2: In the precision forging of blade roots and moving blades, the lateral and longitudinal misalignment of the precision forgings shall not be greater than 1mm, and the residual flash of the precision forgings shall not be greater than 2mm.

[0039] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for processing a vertical tree-shaped blade root moving blade, characterized in that: The specific processing technology is as follows: S1: Forming of pre-forgings: high chromium alloy steel is used to cast the pre-forgings of the blade root and moving blades to be forged; S2: Precision forging of blade roots and moving blades: Place the pre-forged parts into the precision forging die, forge them into shape through the precision forging die, take out the precision forging parts after forming and remove the flash; the surface of the precision forging parts is not allowed to have folds, cracks, pits and inclusions. Defects generated after forging can be removed by grinding, and the grinding depth is not allowed to exceed 1 / 2 of the actual margin, and the width-to-depth ratio of the grinding part is not less than 6:1; S3: Determine the center point: Determine the center at both ends of the precision forging and drill ejector holes at the center point, where the blade crown end face has a single ejector hole and the blade root end face has three ejector holes; and stamp the > symbol on both end faces of the precision forging, with the opening direction being the steam outlet edge; S4: Milling of precision forgings: The precision forgings with the ejector holes drilled are placed on a four-axis machining center using an ejector fixture for milling. The clamping step at the process clamping head is milled by a finger-shaped milling cutter. The milling machine is positioned through the center ejector hole of the process clamp and clamps the clamping step at the process clamping head, reserving the length of the end size to be processed. S4.1: Rough milling: Firstly, rough mill the steam inlet and outlet sides of the blade root and the shroud, rough mill the inner and back arc surfaces of the assembly; rough mill the inner and back arc surfaces of the steam channel and the root crown transition; at the same time, mill out the process datum of the blade root; S4.2: Processing of blade root tooth shape: Use wire cutting to cut the blade root tooth shape at the blade root part, and use wire cutting to cut the total length of the blade crown; use fine milling to mill the blade root end face and blade root tooth shape; S4.3: Radial surface machining: Use fine milling to mill out the inner radial surface and inner bevel angle. The verticality of the inner radial surface to the steam outlet side is ≤0.02, and the angle difference with the back plane is ≤0.02; finally, fine mill the back radial surface; S4.4: Steam duct polishing: Polish the inner arc line, back arc line and transition of the steam duct, and measure the guide vane assembly by using the steam duct line gauge, line template and arc surface guide vane assembly total length gauge; the polishing pattern should be in the same direction as the airflow direction, and the inlet and outlet edges should not be burnt and should not be polished into a knife edge; S4.5: Process clamping end face cutting: After processing to the designed size, the end face is clamped by wire cutting process. The processed surface should not be damaged. The processing is completed.

2. A longitudinal tree-shaped blade root moving blade processing process according to claim 1, characterized in that: S2: In the precision forging of blade roots and moving blades, the lateral and longitudinal offsets of the precision forgings shall not be greater than 1 mm, and the residual flash of the precision forgings shall not be greater than 2 mm.

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