A production process for three-dimensional steam turbine blades

Abstract

The invention discloses a production process of a three-dimensional blade of a steam turbine, which is realized by the following steps: S1, die forging to form a blade forging, specifically including: a, casting of a blade blank, b, preparing a blade forging die, c, heating, d: die forging, S2, positioning and installing the blade forging in step S1: using a special four-axis tooling to rotatably install the blade forging in step S1 on the four-axis tooling, the four-axis tooling is provided with symmetrical installation protrusions, and the installation protrusions are respectively installed corresponding to the installation holes in step S1, so that the central axis of the blade forging is calibrated and installed on the four-axis tooling, S3, milling finishing, S4, cutting and polishing. Compared with the traditional processing method using blade blanks, the invention reduces a large amount of machining time, reduces the number of labor, and improves the production efficiency of the enterprise.

Description

Technical field:

[0002] The invention relates to the technical field of blade production, in particular to a production process for three-dimensional blades of a steam turbine. Background technology:

[0004] Blades are key parts of steam turbines, and are also one of the most delicate and important parts. Steam turbine blades have complex blade profiles, which account for about half of the entire blade during processing. Therefore, blade molding is relatively difficult. Currently, blade production mostly involves adding process heads at both ends of the blank during casting and heat treatment, and processing mounting holes on the process heads. The blade blanks are then installed on CNC milling machines through the mounting holes, and then all machining processes are completed at one time through comprehensive programming.

[0005] However, this heat-treated cast blade blank is relatively rough. When the blade blank is subsequently milled on a CNC machine tool, it still needs to undergo semi-finishing milling and adjust the speed and feed rate of the milling tool, which increases the complexity of the processing technology and hinders the improvement of blade production efficiency. On the other hand, the blades produced by this blade blank have poor metal deformation inside the blade blank, which makes it easy to damage the metal structure inside the blade blank during subsequent milling, resulting in poor density inside the metal and reduced strength of the final blade formation.

[0006] In the prior art, with the further development of blade production technology, the precision die forging of blades has been further developed. Precision die forging is a new process with little cutting and no processing that has been gradually developed on the basis of general die forging. The blades produced by this precision die forging have good surface quality, less machining allowance, high dimensional accuracy, and can make the metal streamlines inside the blades reasonably distributed along the contour of the parts, thereby increasing the strength of the blades. However, this newly developed blade precision forging production process has high requirements, and the cost of its precision forging mold is high. It is difficult for general enterprises to meet the requirements of blade precision die forging production. Therefore, it is urgent to propose an improvement method for the existing blade production process, which can further improve the production efficiency of the enterprise's blades and meet the final blade forming strength while ensuring that the enterprise can produce. Summary of the invention:

[0008] The object of the present invention is to provide a production process for three-dimensional turbine blades to solve one or more of the above-mentioned prior art problems.

[0009] In order to solve the above technical problems, the present invention provides a production process of a three-dimensional turbine blade, the innovation of which is achieved through the following steps:

[0010] S1. Die forging to form a blade forging.

[0011] a. Blade blank casting: When the blank is heated and cast to form the blade blank, symmetrical process heads are integrally formed at both ends of the blade blank.

[0012] b. Prepare a blade forging die: The blade forging die includes an upper die and a lower die, which are closed to form a blade mold cavity, and symmetrical process head mold cavities are provided on both sides of the blade mold cavity. Forging insert rods are provided inside the process head mold cavity, and the forging insert rods are movably arranged inside the process head mold cavity. The moving direction of the forging insert rods is toward the blade mold cavity, and the extension directions of the two forging insert rods are opposite and the connecting line of the two forging insert rods corresponds to the central axis of the blade mold cavity.

[0013] c. Heating: heating the blade blank casting in the above step a to the plastic deformation temperature of the blade blank material.

[0014] d: Die forging: Place the heated blade blank casting in the above step c into the blade die forging die prepared in step b, and under high pressure, forge the heated blade blank casting into a corresponding blade forging, forge the process head into a corresponding process head forging, and forge the interior of the process head forging into a corresponding mounting hole.

[0015] S2. Position and install the blade forging in step S1: Use a special four-axis tooling to rotatably install the blade forging in step S1 on the four-axis tooling. The four-axis tooling is provided with symmetrical mounting protrusions, which are respectively installed corresponding to the mounting holes in step S1, so that the central axis of the blade forging is calibrated and installed on the four-axis tooling.

[0016] S3, milling finishing: adopting the spiral machining method, the blade forging fixed on the four-axis fixture in step S2 is sequentially subjected to the finishing milling of the blade root, the finishing milling of the inner back radial surface and the finishing milling of the blade body.

[0017] S4, cutting and polishing: using an electric spark cutting machine to cut and polish the blade forging after milling and finishing in step S3.

[0018] Furthermore, the forging sequence of the die forging in the above step S1 is to quickly forge the blade cavity and form it into a blade forging, quickly forge the process head cavity and form it into a process head forging, and quickly forge the forged insert rod and form it into a mounting hole, and the rapid forging direction of the forged insert rod is toward the blade cavity.

[0019] Furthermore, the cutting and polishing in the above step S4 includes cutting the process head and polishing the blade body.

[0020] Furthermore, the tool for fine milling the blade root and the tool for fine milling the inner back radial surface in the above step S3 are respectively a blade root special milling cutter and a flat head cutter, and the tool for fine milling the blade body in the above step S3 are respectively a ball head cutter and a bull nose milling cutter.

[0021] Furthermore, the above-mentioned four-axis tooling includes a workbench, on which are provided two parallel clamps, one of which is horizontally movably arranged on the workbench, and a clamping cavity for clamping the blade forging is formed between the two clamps. Rotating bearings are provided on the clamps, and two mounting protrusions are respectively fixed on the rotating bearings. A rotating motor for driving the rotating bearing to rotate is provided on the workbench.

[0022] Furthermore, the above-mentioned mounting protrusions are provided with stabilizing gears, the bottom of the clamping cavity is provided with symmetrical stabilizing rods, the stabilizing rods are provided with transmission gears meshing with the stabilizing gears, and a calibration plate that can move up and down is provided between the two stabilizing rods, and the calibration plate is parallel to the horizontal plane.

[0023] Furthermore, a placement groove for placing the blade forging is provided on the surface of the calibration plate.

[0024] Furthermore, a driving cylinder is provided at the bottom of the clamping cavity, and an output end of the driving cylinder is connected to the bottom of the calibration plate.

[0025] Furthermore, a displacement sensor is provided at the bottom of the clamping cavity, a controller is provided on the driving cylinder, and the displacement sensor and the controller are electrically connected.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention provides a production process for three-dimensional turbine blades. When the blade forging is spirally processed, the blade forging formed by die forging is finely processed into the final blade, without adjusting the rotation speed and feed rate of the milling cutter. Compared with the traditional processing method using blade blanks, a large amount of machining hours is reduced, the number of labor is reduced, and the production efficiency of the enterprise is improved.

[0028] 2. The present invention provides a production process for three-dimensional turbine blades. Before the blade blank is processed into a blade, the blade blank is preferentially die-forged into a blade forging. By preparing a blade forging die, the blade blank is forged in the blade forging die to form a blade forging. The use of such blade forging to form the final blade can ensure that the metal has good forming conditions and a suitable degree of deformation, and ensures that the final formed blade can obtain streamlines and uniform fine grains distributed along the shape of the blade body, thereby improving the strength of the final formed blade.

[0029] 3. The present invention provides a production process for three-dimensional turbine blades. Before the process head of the blade blank is positioned and installed on the four-axis tooling, the process head is forged into a process head forging. The uniformity of the final formed shape of the process head forging is ensured by the prepared process head mold cavity. In the subsequent process of rotating the blade forging by clamping the process head forging, the uniformity of the shape ensures the stable rotation of the blade forging, thereby ensuring the stability of the final blade processing. Description of the drawings:

[0031] Figure 1 It is a schematic diagram of the side structure of the die forging die of the present invention.

[0032] Figure 2 It is a schematic diagram of the side structure of the four-axis tooling of the present invention. Specific implementation method:

[0034] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0035] Example 1

[0036] like Figure 1 to Figure 2 A specific implementation of the embodiment of the present invention is achieved by the following steps:

[0037] S1. Die forging to form a blade forging 101.

[0038] a. Blade blank casting: When the blank is heated and cast to form the blade blank, symmetrical process heads are integrally formed at both ends of the blade blank.

[0039] b. Prepare a blade forging die: The blade forging die includes an upper die 102 and a lower die 103. The upper die 102 and the lower die 103 are closed to form a blade mold cavity. Symmetrical process head mold cavities 104 are provided on both sides of the blade mold cavity. Forging insert rods 105 are provided inside the process head mold cavity 104. The forging insert rods 105 are movably arranged inside the process head mold cavity 104. The moving direction of the forging insert rods 105 is toward the blade mold cavity. The extension directions of the two forging insert rods 105 are opposite and the connecting line of the two forging insert rods 105 corresponds to the central axis of the blade mold cavity.

[0040] c. Heating: heating the blade blank casting in the above step a to the plastic deformation temperature of the blade blank material.

[0041] d: Die forging: Place the heated blade blank casting in the above step c into the blade die forging die prepared in step b, and under high pressure, forge the heated blade blank casting into the corresponding blade forging 101, and forge the process head into the corresponding process head forging 106, and the interior of the process head forging 106 is forged into the corresponding mounting hole 107.

[0042] In an embodiment of the present invention, before the blade blank is processed into a blade, the blade blank is preferentially die-forged into a blade forging 101. By preparing a blade forging die, the specific blade forging die is close to the shape of the final formed blade, and the blade blank is forged in the blade forging die to form a blade forging 101. By using this blade forging 101, the final blade can ensure that the metal has good forming conditions and a suitable degree of deformation, and ensure that the final formed blade can obtain streamlines and uniform fine grains distributed along the shape of the blade body, thereby improving the strength of the final formed blade.

[0043] In an embodiment of the present invention, before the process head of the blade blank is positioned and installed on the four-axis tooling, the process head is forged into a process head forging 106. The uniformity of the final formed shape of the process head forging 106 is ensured by the prepared process head mold cavity 104. In the subsequent process of rotating the blade forging 101 by clamping the process head forging 106, the uniformity of the shape ensures the stable rotation of the blade forging 101, thereby ensuring the stability of the final blade processing.

[0044] In an embodiment of the present invention, the mounting hole 107 on the process head forging 106 is forged on the process head forging 106 by forging an insert rod 105. The forged mounting hole 107 has high mechanical properties, ensuring the stability of the subsequent clamping of the mounting hole 107 on the four-axis tooling, thereby ensuring the stability of the blade processing on the four-axis tooling. At the same time, the forged mounting hole 107 is relatively symmetrical on both sides of the blade forging 101, thereby ensuring that the connecting line position of the two mounting holes 107 and the axial position of the blade forging 101 are consistent, thereby improving the accuracy of subsequent blade forging 101 processing.

[0045] S2. Position and install the blade forging in step S1: Use a special four-axis tooling to rotatably install the blade forging 101 in step S1 on the four-axis tooling. The four-axis tooling is provided with symmetrical mounting protrusions 1, and the mounting protrusions 1 are respectively installed corresponding to the mounting holes 107 in step S1, so that the central axis of the blade forging 101 is calibrated and installed on the four-axis tooling.

[0046] In an embodiment of the present invention, the axis of the blade forging 101 in the above step S1 is calibrated and installed on the four-axis tooling through a dedicated four-axis tooling, ensuring that the axis position of the blade forging 101 processed on the four-axis tooling is consistent with the axis position of the blade forging 101 itself, thereby further ensuring the accuracy of the final blade processing.

[0047] S3, milling finishing: adopting the spiral machining method, the blade forging fixed on the four-axis fixture in step S2 is sequentially subjected to the finishing milling of the blade root, the finishing milling of the inner back radial surface and the finishing milling of the blade body.

[0048] In the embodiment of the present invention, the spiral processing method refers to a processing method that uses a spiral tool path cutting along the radial direction of the blade and feeds in the axial direction of the product. It is a common cutting method in machining and is not described in detail in the embodiment of the present invention. When the blade forging 101 is spirally processed, the blade forging 101 formed by die forging is finely processed into the final blade. Compared with the traditional processing method using blade blanks, a large amount of machining hours are reduced, the number of labor is reduced, and the production efficiency of the enterprise is improved.

[0049] S4, cutting and polishing: using an electric spark cutting machine to cut and polish the blade forging after milling and finishing in step S3.

[0050] In the embodiment of the present invention, after the blade is finally formed, the surface is polished, the process head and

[0051] The finished blade is obtained by wire cutting the end surface of the total length of the blade and other processes.

[0052] In an embodiment of the present invention, the forging sequence of the die forging in the above-mentioned step S1 is to quickly forge the blade cavity and form it into a blade forging 101, to quickly forge the process head cavity and form it into a process head forging 106, and to quickly forge the forged insert rod 105 and form it into a mounting hole 107. The rapid forging direction of the forged insert rod 105 is toward the blade cavity. During the entire die forging process, the blade forging 101, the process head forging 106 and the mounting hole 107 are forged in a forging sequence from inside to outside, which can effectively guide the flow of metal inside the blade cavity and the process head cavity, thereby meeting the die forging of the complex shape of the blade forging 101.

[0053] In the embodiment of the present invention, the cutting and polishing in the above step S4 includes cutting the process head and polishing the blade body.

[0054] In an embodiment of the present invention, the tool for fine milling of the blade root and the tool for fine milling of the inner back radial surface in the above step S3 are respectively a special milling cutter for the blade root and a flat-head cutter, and the tool for fine milling of the blade body in the above step S3 are respectively a ball-end cutter and a bull nose milling cutter. When processing the blade root, the inner back radial surface and the blade body, the rotation speed of the special milling cutter for the blade root, the flat-head cutter, the ball-end cutter and the bull nose milling cutter directly reaches 4000r / min, and the feed rate directly reaches 3000mm / min, without the need for adjustment, the machining time is short, and the company's work efficiency is high.

[0055] Example 2

[0056] like Figure 1 As shown, an embodiment of the present invention provides a four-axis tooling, which includes a workbench 2, on which two parallel clamping plates 3 are provided, one of which is horizontally movably arranged on the workbench 2, and a clamping cavity 4 for clamping a blade forging 101 is formed between the two clamping plates 3, and a rotating bearing 31 is provided on the clamping plates 3, and two mounting protrusions 1 are respectively fixed on the rotating bearing 31, and a rotating motor 5 for driving the rotating bearing 31 to rotate is provided on the workbench 2.

[0057] In an embodiment of the present invention, according to the length of the blade forging 101 in Example 1, the distance between the clamps 3 is adjusted, and the distance corresponds to the length of the blade forging 101. When the blade forging 101 is installed in the clamping cavity 4, the mounting protrusions 1 are respectively embedded in the inside of the mounting holes 107 one by one, so that the blade forging 101 can be rotatably set inside the clamping cavity 4. When the blade forging 101 is milled and finished, the rotating motor 5 is turned on. Specifically, the rotating motor 5 is installed on the clamping plate 3 fixed on the workbench 2 and connected to the bearing on the above-mentioned fixed clamping plate 3. Driven by the rotating motor 5, the blade forging 101 rotates inside the clamping cavity 4. At the same time, the milling tool performs milling and finishing on the blade forging 101 according to the rotation speed and feed rate provided in Example 1 until the finishing of the blade forging 101 is completed.

[0058] In the embodiment of the present invention, the above-mentioned mounting protrusions 1 are all provided with stabilizing gears 6, the bottom of the clamping cavity 4 is provided with symmetrical stabilizing rods 7, the stabilizing rods 7 are provided with transmission gears 71 meshingly connected with the stabilizing gears 6, and a calibration plate 8 that can move up and down is provided between the two stabilizing rods 7, and the calibration plate 8 is parallel to the horizontal plane. During the rotation of the blade forging 101, the meshing connection between the stabilizing gear 6 and the transmission gear 71 ensures the stability of the rotation of the mounting protrusion 1, thereby ensuring the stability of the rotation of the blade forging 101. At the same time, when the blade forging 101 is calibrated and installed inside the clamping cavity 4, the blade forging 101 is preferably placed on the calibration plate 8. By placing the calibration plate 8 on the calibration plate 8, the blade forging 101 is calibrated and installed inside the clamping cavity 4. Move downward to align the mounting holes 107 on both sides of the blade forging 101 with the mounting protrusions 1 respectively, and then align the mounting protrusions 1 and the mounting holes 107 for installation. This installation method of the blade forging 101 in the clamping cavity 4 ensures, on the one hand, that the axes of the calibration plate 8 and the blade forging 101 are parallel to each other, thereby improving the accuracy of the calibration installation of the axis position of the blade forging 101 in the clamping cavity 4; on the other hand, the up and down movement of the calibration plate 8 enables each subsequent blade forging 101 to be in the same horizontal plane when installed with the mounting hole 107, thereby ensuring the consistency of the installation position of each blade forging 101 and the consistency of the milling finishing of each blade forging.

[0059] In an embodiment of the present invention, a placement groove 81 for placing the blade forging is opened on the surface of the above-mentioned calibration plate 8. Specifically, the shape of the placement groove 81 corresponds to the shape of the blade forging 101, so that the blade forging 101 is conveniently placed inside the placement groove 81. As the calibration plate 8 moves up and down, the placement groove 81 moves up and down with the calibration plate 8. When the mounting holes 107 and the mounting protrusions 1 on both sides of the blade forging 101 are installed, the horizontal position of the placement groove 81 and the mounting protrusions 1 are flush with each other, so as to facilitate the installation between the mounting holes 107 and the mounting protrusions 1.

[0060] In an embodiment of the present invention, a driving cylinder 41 is provided at the bottom of the clamping cavity 4, and the output end of the driving cylinder 41 is connected to the bottom of the calibration plate 8. A displacement sensor 42 is provided at the bottom of the clamping cavity 4, and a controller is provided on the driving cylinder 41. The displacement sensor 42 and the controller are electrically connected. In the process of the driving cylinder 41 driving the calibration plate 8 to move up and down, the distance between the calibration plate 8 and the horizontal plane is monitored by the displacement sensor 42, and the driving cylinder is controlled by the controller to drive the calibration plate 8 up and down. Specifically, when the horizontal position of the placement groove 81 and the mounting protrusion 1 are horizontally aligned, the distance between the calibration plate 8 and the horizontal plane is measured in advance as a, and the displacement distance of the calibration plate 8 is pre-set by the displacement sensor 42 to pre-set the displacement distance of the calibration plate 8, so that the distance between the calibration plate 8 and the horizontal plane reaches a, thereby ensuring that each time the driving cylinder 41 drives the calibration plate 8 to move upward, the stop position of the calibration plate 8 is the installation position between the mounting hole 107 on the mounting groove 81 and the mounting protrusion 1.

[0061] 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 production process for three-dimensional turbine blades, characterized in that This is accomplished by the following steps: S1. Die forging to form a blade forging (101): a. Blade blank casting: when the blank is heated and cast to form the blade blank, symmetrical process heads are integrally formed at both ends of the blade blank; b. Preparing a blade forging die: the blade forging die comprises an upper die (102) and a lower die (103), the upper die (102) and the lower die (103) being closed to form a blade die cavity, symmetrical process head die cavities (104) being provided on both sides of the blade die cavity, forging insert rods (105) being provided inside the process head die cavity (104), the forging insert rods (105) being movably arranged inside the process head die cavity (104), the moving direction of the forging insert rods (105) being toward the blade die cavity, the extension directions of the two forging insert rods (105) being opposite, and the connecting line of the two forging insert rods (105) corresponding to the central axis of the blade die cavity; c. Heating: heating the blade blank casting in step a to the plastic deformation temperature of the blade blank material; d: Die forging: placing the heated blade blank casting in step c into the blade die forging die prepared in step b, and forging the heated blade blank casting into a corresponding blade forging (101) under high pressure, the process head forging into a corresponding process head forging (106), and the interior of the process head forging (106) into a corresponding mounting hole (107); S2, positioning and installing the blade forging in step S1: using a dedicated four-axis tooling to rotatably install the blade forging (101) in step S1 on the four-axis tooling, the four-axis tooling is provided with symmetrical mounting protrusions (1), and the mounting protrusions (1) are respectively installed corresponding to the mounting holes (107) in step S1, so that the central axis of the blade forging (101) is calibrated and installed on the four-axis tooling; S3, milling finishing: using a spiral machining method, sequentially performing finishing milling of the blade root, finishing milling of the inner back radial surface, and finishing milling of the blade body on the blade forging fixed on the four-axis tooling in step S2; S4, cutting and polishing: using an electric spark cutting machine to cut and polish the blade forging after milling and finishing in step S3; The four-axis tooling comprises a workbench (2), wherein two clamping plates (3) are provided on the workbench (2), wherein one of the clamping plates (3) is horizontally movably arranged on the workbench (2), a clamping cavity (4) for clamping the blade forging (101) is formed between the two clamping plates (3), a rotating bearing (31) is provided on each of the clamping plates (3), and the two mounting protrusions (1) are respectively fixed on the rotating bearings (31), and a rotating motor (5) for driving the rotating bearings (31) to rotate is provided on the workbench (2); The mounting protrusions (1) are each provided with a stabilizing gear (6), the bottom of the clamping cavity (4) is provided with a symmetrical stabilizing rod (7), the stabilizing rod (7) is provided with a transmission gear (71) meshingly connected with the stabilizing gear (6), and a calibration plate (8) movable up and down is provided between the two stabilizing rods (7), the calibration plate (8) being parallel to a horizontal plane; The surface of the calibration plate (8) is provided with a placement groove (81) for placing the blade forging.

2. The production process of a three-dimensional steam turbine blade according to claim 1, characterized in that: The forging sequence of the die forging in step S1 is, in sequence, rapid forging the blade die cavity to form the blade forging (101), rapid forging the process head die cavity to form the process head forging (106), and rapid forging the forged insert rod (105) to form the mounting hole (107), wherein the rapid forging direction of the forged insert rod (105) is toward the blade die cavity.

3. The production process of a three-dimensional steam turbine blade according to claim 1, characterized in that: The cutting and polishing in step S4 includes cutting the process head and polishing the blade body.

4. The production process of a three-dimensional steam turbine blade according to claim 1, characterized in that: The tool for fine milling the blade root and the tool for fine milling the inner back radial surface in step S3 are respectively a blade root special milling cutter and a flat head cutter, and the tool for fine milling the blade body in step S3 is respectively a ball end cutter and a bull nose milling cutter.

5. The production process of a three-dimensional steam turbine blade according to claim 1, characterized in that: A driving cylinder (41) is provided at the bottom of the clamping cavity (4), and an output end of the driving cylinder (41) is connected to the bottom of the calibration plate (8).

6. The production process of a three-dimensional steam turbine blade according to claim 5, characterized in that: A displacement sensor (42) is provided at the bottom of the clamping cavity (4), a controller is provided on the driving cylinder (41), and the displacement sensor (42) and the controller are electrically connected.

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