Machining method for two sides of blade root of special-material large blade of steam turbine

Abstract

The invention relates to the field of machining, in particular to a method for machining the two sides of a blade root of a special-material large blade of a steam turbine, and aims at solving the problems that in the machining mode that the blade root and a blade crown of the special large blade of the steam turbine are machined through a six-point positioning clamp, the size parameter angle needs to be noticed, and machining is difficult. According to the scheme, the clamp is placed on a numerical control horizontal machine tool platform, the blade is placed in the clamp, six-point positioning natural attachment is guaranteed, after the height of the auxiliary supporting device is adjusted to enable the supporting height of the auxiliary supporting device to meet the requirement, the pressing device is adjusted to press the blade root machining part, and then the clamping devices on the two sides of the blade crown are adjusted; meanwhile, it is guaranteed that after pressing, six-point positioning points of the clamp are tightly attached to six positioning points of the blade, it is guaranteed that a filler gauge does not enter 0.02 mm, then the most end of the blade root on the steam inlet side and all the end faces on the steam inlet side are machined in sequence, and after machining is completed, the clamp is turned by 180 degrees, and all the end faces on the steam outlet side are machined. And after clamping, conversion positioning does not affect the machining precision and stability.

Description

Technical Field

[0001] The invention relates to the field of mechanical processing, and in particular to a method for processing both sides of a blade root of a large-scale steam turbine blade made of special material. Background Art

[0002] A special large blade for steam turbine, the processing method is to use a six-point positioning fixture to process the blade root and blade crown. The blade is long and difficult to process, and the processing volume is large. Because it is positioned on the side, each tooth shape is processed in a vertical direction, the tool wears quickly, the size control is inaccurate, and the diamond angle with the already processed radial surface and side surface must be guaranteed.

[0003] In summary, the processing method of the special large turbine blades using a six-point positioning fixture to process the blade root and blade crown requires attention to the dimensional parameters and angles, which are not easy to control and make the processing more difficult. Summary of the invention

[0004] Purpose of the patent of this invention: In order to solve the problem that the processing method of the blade root and the blade crown of the special large blade of the turbine is processed by a six-point positioning fixture, the dimensional parameters and angles that need to be paid attention to are not easy to control and the processing is more difficult, this invention proposes a method for processing both sides of the blade root of a large blade of a special material for a turbine.

[0005] The present invention is achieved through the following scheme:

[0006] A method for processing both sides of the blade root of a large blade made of special material for a steam turbine, comprising the following steps:

[0007] Step 1: Before clamping the blade, check the six points of the blade to be positioned to ensure that they meet the manufacturing requirements of the blank; the three points of the blade's processed radial surface and the blade's bottom surface to ensure that they meet the geometric accuracy technical requirements;

[0008] Step 2: Place the fixture on the CNC horizontal machine platform, first prepare the reference side of the steam inlet side of the blade to be processed, install the tool on the horizontal machine to prepare for processing, check with a dial indicator and a height gauge to ensure that the six positioning points on the fixture meet the design requirements and are consistent with the six positioning points of the blade to be processed, adjust the fixture so that the flatness and position of the measuring surface meet the requirements, straighten and level the upper and lower end faces, front and rear end faces, and left and right end faces of the fixture;

[0009] Step 3: Put the blade into the fixture, ensure that the six-point positioning is naturally tight, and ensure that the feeler gauge does not penetrate 0.02mm; adjust the height of the auxiliary support device to make its support height meet the requirements, adjust the clamping device to clamp the blade root processing part, and then adjust the clamping devices on both sides of the blade crown, and ensure that the six-point positioning points of the fixture are tightly pressed and the six positioning points of the blade, and ensure that the feeler gauge does not penetrate 0.02mm;

[0010] Step 4: Check the surface of the clamped workpiece and the reference surface of the fixture to ensure levelness;

[0011] Step 5: Process the end of the blade root on the steam inlet side, install a φ10mm alloy rod end mill, adjust the processing parameters and start processing; after processing is completed, process the vicinity of the end of the blade root on the steam inlet side, and the processing tool and processing parameters are the same as when processing the end of the blade root on the steam inlet side.

[0012] Step six: Process the step part on the steam inlet side, install a φ10mm alloy rod end mill, adjust the processing parameters, adjust the clamping devices on both sides of the blade crown to between the end of the machined steam inlet side blade root and the vicinity of the end of the steam inlet side blade root, make the positioning points of the clamping devices on both sides of the blade crown fit and fix the workpiece until it is processed to be parallel to the first tooth and the second tooth, and the error between the two is within ±0.01mm; process the side surface of the steam seal tooth on the steam inlet side; the processing tool and processing parameters are the same as when processing the step part on the steam inlet side.

[0013] Step 7: After processing all parts of the steam inlet side of the blade, turn the fixture 180°, straighten the fixture in the longitudinal and vertical directions, ensure that the height difference within 100mm of the horizontal position of the blade is less than 0.03mm, and repeat steps 5 and 6 to process the steam outlet side of the blade.

[0014] Furthermore, in the step 1, the error between the measured dimensions of the blade radial surface at the three-coordinate position and the standard dimension is within 0.03 mm.

[0015] Furthermore, when processing the side close to the top of the blade root in step 5, the processing parameters are a spindle speed of 350 rpm, a feed speed of 30 mm / min, and a cutting depth of 0.4 mm.

[0016] Furthermore, when processing the step portion on the steam inlet side in step six, the processing parameters are a spindle speed of 250 rpm, a cutting speed of 40 mm / min, and a cutting depth of 0.5 mm.

[0017] Furthermore, the φ10 mm alloy rod end mill in step five is a long shank tool.

[0018] Furthermore, when processing the end of the blade root on the steam inlet side in step 5, a 5mm block gauge is placed on the measuring surface and compared with the processing surface until the technical requirement of ±0.05mm is met.

[0019] Furthermore, the φ10 mm alloy rod end mills in step six are all long shank tools.

[0020] Furthermore, when processing the side surface of the steam seal tooth on the steam inlet side in step six, a 33mm block gauge is placed on the measuring surface and compared with the processed surface until the technical requirement of ±0.05mm is met.

[0021] Beneficial effects:

[0022] This processing method is to process a single tooth profile side (inlet side / exit side) to ensure the consistency of the diamond angle and plane with the radial surface. This method can ensure the stability of the workpiece processed by the six-point positioning of the fixture and the quality of the processing. The conversion positioning after clamping does not affect the processing accuracy and stability. This processing method and processing parameters, measurements and steps can avoid the processing stability of small tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a blade clamped by a clamp in the present invention;

[0024] Figure 2 It is a schematic diagram of the blade root of the present invention. DETAILED DESCRIPTION

[0025] Specific implementation method 1: A method for processing both sides of the blade root of a large blade made of special material for a steam turbine, which comprises the following steps:

[0026] Step 1: Before clamping the blade, check the six points of the blade to be positioned to ensure that they meet the manufacturing requirements of the blank; the three points of the blade's processed radial surface and the blade's bottom surface to ensure that they meet the geometric accuracy technical requirements;

[0027] Step 2: Place the fixture 1 on the CNC horizontal machine platform, first prepare the reference side of the steam inlet side of the blade to be processed, install the tool on the horizontal machine to prepare for processing, check with a dial indicator and a height gauge to ensure that the six positioning points on the fixture 1 meet the design requirements and are consistent with the six positioning points of the blade to be processed, adjust the fixture 1 so that its measuring surface flatness and position meet the requirements, straighten and level the upper and lower end faces, front and rear end faces, and left and right end faces of the fixture 1;

[0028] Step 3: Put the blade into the fixture 1, ensure that the six-point positioning is naturally tight, and ensure that the feeler gauge does not penetrate 0.02mm; adjust the height of the auxiliary support device 3 so that its support height meets the requirements, adjust the clamping device 2 to clamp the blade root processing part, and then adjust the clamping devices 4 on both sides of the blade crown, and ensure that the six-point positioning points of the fixture 1 are tightly pressed and the six positioning points of the blade, and ensure that the feeler gauge does not penetrate 0.02mm;

[0029] Step 4: Check the surface of the clamped workpiece and the reference surface of the fixture to ensure levelness;

[0030] Step 5: Process the end of the blade root on the steam inlet side, install a φ10mm alloy rod end mill, adjust the processing parameters and start processing; after processing is completed, process the vicinity of the end of the blade root on the steam inlet side, and the processing tool and processing parameters are the same as when processing the end of the blade root on the steam inlet side.

[0031] Step six: Process the step part on the steam inlet side, install a φ10mm alloy rod end mill, adjust the processing parameters, adjust the clamping devices on both sides of the blade crown to between the end of the machined steam inlet side blade root and the vicinity of the end of the steam inlet side blade root, make the positioning points of the clamping devices on both sides of the blade crown fit and fix the workpiece until it is processed to be parallel to the first tooth and the second tooth, and the error between the two is within ±0.01mm; process the side surface of the steam seal tooth on the steam inlet side; the processing tool and processing parameters are the same as when processing the step part on the steam inlet side.

[0032] Step 7: After processing all parts of the steam inlet side of the blade, turn the fixture 180°, straighten the fixture in the longitudinal and vertical directions, ensure that the height difference within 100mm of the horizontal position of the blade is less than 0.03mm, and repeat steps 5 and 6 to process the steam outlet side of the blade.

[0033] In this embodiment: in step 3, since the six-point positioning is relatively weak, auxiliary support and positioning are added at the same time, and the processing stability must be ensured after pressing.

[0034] During step 4 to step 7, when processing both sides of the blade, a large tool cannot be used for one-time forming. A small tool should be used for vertical processing, and each tooth shape should be processed one by one to ensure that the diamond angle with the radial surface is 12°±0.03′.

[0035] Step 4: Use a dial indicator to mark the radial surface of the clamped blade, and move the hand-cranked machine tool horizontally 100mm. According to the 12° ratio of the radial surface and the diamond angle on the steam inlet side, the horizontal angle within 100mm is 21.26mm±0.01, and the tolerance is within 0.02mm. Otherwise, adjust the horizontal angle of the fixture until it is parallel to ① and within ±0.01.

[0036] Specific implementation method 2: A method for processing both sides of the root of a large-scale turbine blade made of special material: in step 1, the error between the measured size of the blade radial surface at the three-coordinate position and the standard size is within 0.03mm.

[0037] Other implementations are the same as the first specific implementation.

[0038] Specific implementation method three: A method for processing both sides of the blade root of a large blade made of special material for a steam turbine. When processing the side close to the top of the blade root in step five, the processing parameters are a spindle speed of 350 rpm, a feed speed of 30 mm / min, and a cutting depth of 0.4 mm.

[0039] In this embodiment: when processing the side close to the top of the blade root in step five, the processing parameters are a spindle speed of 350 rpm, a feed speed of 30 mm / min, and a cutting depth of 0.4 mm. Processing according to these parameters can ensure work efficiency while avoiding excessive tool wear.

[0040] Other implementations are the same as the first specific implementation.

[0041] Specific implementation method 4: A method for processing both sides of the root of a large blade made of special material for a steam turbine. When processing the step portion on the steam inlet side in step 6, the processing parameters are a spindle speed of 250 rpm, a cutting speed of 40 mm / min, and a cutting depth of 0.5 mm.

[0042] In this embodiment: when processing the step portion on the steam inlet side in step six, the processing parameters are a spindle speed of 250 rpm, a cutting speed of 40 mm / min, and a cutting depth of 0.5 mm. Processing according to these parameters can ensure work efficiency while avoiding excessive tool wear.

[0043] Other implementations are the same as the first specific implementation.

[0044] Specific implementation method five: A method for processing both sides of the root of a large blade made of special material for a steam turbine, wherein the φ10mm alloy rod end mill in step five is a long shank tool.

[0045] In this embodiment: a long shank tool is used for processing, which is suitable for the processing method of this solution.

[0046] Other implementations are the same as the first specific implementation.

[0047] Specific implementation method six: A method for processing both sides of the blade root of a large blade made of special materials for a steam turbine. When processing the end of the blade root on the steam inlet side in step five, a 5mm block gauge is placed on the measuring surface and compared with the processing surface until the technical requirement of ±0.05mm is met.

[0048] In this embodiment, a block gauge is placed on the measuring surface and compared with the processing surface, so that the measurement can be completed quickly and the work efficiency is high.

[0049] Other implementations are the same as the first specific implementation.

[0050] Specific implementation method seven: A method for processing both sides of the root of a large blade made of special material for a steam turbine, wherein the φ10 mm alloy rod end mills in step six are all long shank tools.

[0051] In this embodiment: a long shank tool is used for processing, which is suitable for the processing method of this solution.

[0052] Other implementations are the same as the first specific implementation.

[0053] Specific implementation method eight: A method for processing both sides of the root of a large blade made of special material for a steam turbine. When processing the side surface of the steam seal tooth on the steam inlet side in step six, a 33mm block gauge is placed on the measuring surface and compared with the processing surface until the technical requirement of ±0.05mm is met.

[0054] In this embodiment, a block gauge is placed on the measuring surface and compared with the processing surface, so that the measurement can be completed quickly and the work efficiency is high.

[0055] Other implementations are the same as the first specific implementation.

Claims

1. A method for processing both sides of the blade root of a large blade made of special material for a steam turbine, characterized in that: It includes the following steps: Step 1: Before clamping the blade, check the six points of the blade to be positioned to ensure that they meet the manufacturing requirements of the blank; the three points of the blade's processed radial surface and the blade's bottom surface to ensure that they meet the geometric accuracy technical requirements; Step 2: The fixture (1) is placed on the CNC horizontal machine tool platform, and the steam inlet side of the blade to be processed is prepared first. The tool is installed on the horizontal machine tool to prepare for processing. A dial indicator and a height gauge are used to check to ensure that the six positioning points on the fixture (1) meet the design requirements and are consistent with the six positioning points of the blade to be processed. The fixture (1) is adjusted so that the flatness and position of its measuring surface meet the requirements, and the upper and lower end faces, front and rear end faces, and left and right end faces of the fixture (1) are straightened and leveled; Step 3: Place the blade into the fixture (1) to ensure that the six-point positioning is naturally tight and that the feeler gauge does not penetrate 0.02 mm; adjust the height of the auxiliary support device (3) so that its support height meets the requirements, adjust the clamping device (2) to clamp the blade root processing part, and then adjust the clamping devices (4) on both sides of the blade crown, and ensure that the six-point positioning points of the fixture (1) are tightly pressed and the six positioning points of the blade are tightly pressed, and ensure that the feeler gauge does not penetrate 0.02 mm; Step 4: Check the surface of the clamped workpiece and the reference surface of the fixture to ensure levelness; Step 5: Process the end of the blade root on the steam inlet side, install a φ10mm alloy rod end mill, adjust the processing parameters and start processing; after processing is completed, process the vicinity of the end of the blade root on the steam inlet side, and the processing tool and processing parameters are the same as when processing the end of the blade root on the steam inlet side. Step 6: Process the step part on the steam inlet side, install a φ10mm alloy rod end mill, adjust the processing parameters, and adjust the clamping devices (4) on both sides of the blade crown to between the end of the processed steam inlet side blade root and the vicinity of the end of the steam inlet side blade root, so that the positioning points of the clamping devices (4) on both sides of the blade crown fit the workpiece and then fix it until it is processed to be parallel to the first tooth and the second tooth, and the error between the two is within ±0.01mm; process the side surface of the steam seal tooth on the steam inlet side; the processing tool and processing parameters are the same as those for processing the step part on the steam inlet side. Step 7: After processing all parts of the steam inlet side of the blade, turn the fixture 180°, straighten the fixture in the longitudinal and vertical directions, ensure that the height difference within 100mm of the horizontal position of the blade is less than 0.03mm, and repeat steps 5 and 6 to process the steam outlet side of the blade.

2. A method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: In the step 1, the error between the measured dimensions of the blade radial surface at the three-coordinate position and the standard dimension is within 0.03 mm.

3. The method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: When processing the side close to the top of the blade root in step 5, the processing parameters are a spindle speed of 350 rpm, a feed speed of 30 mm / min, and a cutting depth of 0.4 mm.

4. The method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: When processing the step portion on the steam inlet side in step six, the processing parameters are: spindle speed 250 rpm, cutting speed 40 mm / min, and cutting depth 0.5 mm.

5. The method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: The φ10 mm alloy rod end mill in step 5 is a long shank tool.

6. The method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: When processing the end of the blade root on the steam inlet side in step 5, a 5mm block gauge is placed on the measuring surface and compared with the processing surface until the technical requirement of ±0.05mm is met.

7. The method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: The φ10 mm alloy rod end mills in step six are all long shank tools.

8. The method for processing both sides of the blade root of a large steam turbine blade made of special material according to claim 1, characterized in that: When machining the side surface of the steam seal tooth on the steam inlet side in the step 6, a 33mm block gauge is placed on the measuring surface and compared with the machining surface until the technical requirement of ±0.05mm is met.

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