A welding method for the stator blade ring of a gas turbine compressor by electron beam welding

Abstract

The present invention discloses a method for assembling and welding a compressor stator vane ring of a gas turbine by electron beam welding, belonging to the field of assembling and welding before electron beam welding of the compressor stator vane ring of a gas turbine, and comprising the following steps: demagnetizing the stator vanes and corresponding tooling, wherein the stator vanes include standard vanes and adjusting vanes; cleaning the stator vanes and corresponding tooling; performing trial assembly and calculating the grinding amount of the adjusting vanes according to the gaps generated during assembly, and assembling the standard vanes and adjusting vanes into a stator vane ring; using welding to fix the joints of the inner and outer circles of adjacent vanes; assembling welding tooling and performing overall demagnetization treatment; placing desiccants, wrapping with plastic film and then packing in a box to protect the assembled stator vane ring; solving the problem in the prior art that due to the machining accuracy and assembly accuracy of the stator vanes, when assembled into a stator vane ring, the actual circumferential dimension may not conform to the setting, resulting in the stator vane ring being unable to be installed or having gaps after installation.

Description

Technical Field

[0001] The present invention relates to the field of pre-assembly and welding of compressor stator blade rings of gas turbines before electron beam welding, and particularly to a method for pre-assembly and welding of electron beam welded gas turbine compressor stator blade rings. Background Art

[0002] The compressor of a gas turbine contains multiple stages of stator blade rings. A typical structure is as Figure 1 , each blade is integrally processed from a forging and includes three parts: an outer band (outer circle), a blade body, and an inner band (inner circle). Each stage of the stator blade ring consists of about 50 - 200 blades forming a circle, and circumferential electron beam circumferential welds are arranged on the axial end face to be welded into one body. Generally, vacuum electron beam welding requires small assembly gaps, precise dimensions, and residual magnetism Br ≤ 2 GS for the workpieces to be welded, and it is preferably welded in the vacuum chamber within 4 hours after the workpieces are cleaned. According to the above requirements, this type of stator blade ring will encounter the following problems: The stator blade ring consists of a large number of stator blades. Due to the machining accuracy and assembly accuracy of the stator blades, when assembling into a stator blade ring, the actual circumferential dimension may not match the set value, resulting in the stator blade ring being unable to be installed or having gaps after installation.

[0003] For example, in the "Detachable Compressor Stator Blade Ring of Ship Gas Turbine and Its Assembly Method" disclosed in the Chinese patent literature, with the publication number CN113513374A, the blade ring, ordinary stator blades, and two stator blades with notches at the lower edge plates. The blade ring includes an outer ring and an inner ring, and a card slot is provided on the entire inner ring; the blade ring consists of two split half blade rings, and the split cut divides the card slot into two half card slots. First, the two stator blades with notches at the lower edge plates are respectively slid into the half card slots along the cuts of the two split half blade rings and cooperate with the stop blocks; then the ordinary stator blades with complete upper and lower edge plate structures are installed in sequence; finally, the two split half blade rings are spliced to form a complete stator blade ring. This invention has the advantages of flexible structure, convenient installation and disassembly, and can be applied to compressors of different structural forms. However, its disadvantage is that due to the machining accuracy and assembly accuracy of several stator blades, when assembling the last stator blade, it may be impossible to assemble or there may still be gaps after assembly, which may lead to deformation of the stator blade ring during the subsequent electron beam welding process. Summary of the Invention

[0004] The present invention is to overcome the problem in the prior art that due to the machining accuracy and assembly accuracy of the stator blades, when assembling into a stator blade ring, the actual circumferential dimension may not match the set value, resulting in the stator blade ring being unable to be installed or having gaps after installation, and provides a method for pre-assembly and welding of electron beam welded gas turbine compressor stator blade rings, which can ensure that the dimensional accuracy of the assembled stator blade ring and the position accuracy of each stator blade meet the requirements.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention relates to a method for assembling and welding a compressor stator blade ring by electron beam welding, which includes the following steps:

[0007] S1. Demagnetize the stator blades and the corresponding tooling. The stator blades include standard blades and adjusting blades.

[0008] S2. Clean the stator blades and the corresponding tooling.

[0009] S3. Conduct a trial assembly, calculate the grinding amount of the adjusting blades based on the gaps generated during the assembly, and assemble the standard blades and the adjusting blades into a stator blade ring.

[0010] S4. Use welding to fix the seams of the inner and outer circles of adjacent blades.

[0011] S5. Assemble the welding tooling and conduct overall demagnetization treatment.

[0012] S6. Place desiccants, wrap them with plastic film, and then pack them in a box to protect the assembled stator blade ring.

[0013] In this application, the stator blades that make up the stator blade ring are divided into standard blades and adjusting blades. By grinding the adjusting blades, their dimensions can be trimmed, so that the overall dimensions of the stator blade ring can be adjusted, avoiding the situation where the overall assembly accuracy of the stator blade ring is insufficient due to the insufficient machining accuracy of each stator blade, ensuring that the assembled stator blade ring has a small assembly gap, accurate dimensions, and extremely small welding deformation after electron beam welding.

[0014] Preferably, step S1 further includes the following steps:

[0015] S11. Use a demagnetizer to demagnetize the stator blades and the welding tooling.

[0016] S12. Measure the residual magnetism of the workpiece. The qualified residual magnetism Br ≤ 2 GS.

[0017] Preferably, step S2 further includes the following steps:

[0018] S21. Clean the stator blades and the corresponding tooling.

[0019] S22. Wipe the stator blades and the corresponding tooling with alcohol or acetone.

[0020] S23. Inspect the cleanliness.

[0021] S24. Wrap with plastic film in time to prevent the stator blades and the corresponding tooling from being contaminated.

[0022] The above steps can ensure the cleanliness of the stator blade ring before assembly.

[0023] Preferably, step S3 further includes the following steps:

[0024] S31. Wipe the assembly table clean with alcohol or acetone, and perform the assembly using clean gloves;

[0025] S32. Take 3 - 5 standard blades, perform the pilot assembly through the welding fixture, check whether the radiation lines of the blades are aligned with those shown in the drawing, make alignment adjustments, and mark them as the standard blades for the first blade;

[0026] S33. Assemble each standard blade and adjusting blade according to the design drawing. Every 5 - 8 stationary blades, fix the stationary blades on the welding fixture through the wedge block;

[0027] S34. When assembling the last stationary blade, perform the gap measurement, calculate the grinding allowance based on the measurement results, and grind and adjust the assembly surface of the blade according to the grinding allowance;

[0028] S35. After the adjusting blade is ground and passes the trial assembly, demagnetize the adjusting blade, with the requirement that the residual magnetism Br ≤ 2 GS, and clean it thoroughly;

[0029] S36. Mark all the adjusting blades;

[0030] S37. Wipe all the stationary blades and the fixture again with alcohol or acetone;

[0031] S38. Re - assemble and fasten each standard blade and adjusting blade according to steps S32 and S33, and install the last stationary blade;

[0032] S39. Check the following assembly dimensions of the blades: the axial step difference between adjacent blades ≤ 0.5 mm; the radial step difference between adjacent blades on the inner and outer shrouds of the flow path surface ≤ 0.5 mm; the joint of the shrouds of adjacent blades is light - tight, most of the gaps cannot be inserted with a feeler gauge, and individual gaps are allowed with a size not exceeding 0.20 mm;

[0033] S310. Wrap the plastic film in time to prevent the workpiece from being contaminated.

[0034] In this solution, through the described pilot assembly, the assembly of the first few stationary blades can be inspected and its assembly accuracy can be ensured, providing a benchmark for subsequent assembly, thus reducing the situation where the entire stationary blade ring needs to be re - assembled due to errors in the starting position; through the cleaning after grinding the adjusting blade and the re - wiping of the stationary blades and the fixture, the situation where the stationary blades and the fixture are contaminated by debris and dust generated during the assembly and grinding processes can be avoided.

[0035] Preferably, step S4 further includes the following steps:

[0036] S41. Weld the stationary blades into a stationary blade ring at the joints of the inner and outer circles of adjacent stationary blades;

[0037] S42. Check the weld defects;

[0038] S43. Wrap the plastic film in time to prevent the workpiece from being contaminated.

[0039] The welding through the inner and outer circle seams can improve the welding reliability.

[0040] Preferably, the step S5 further includes the following steps:

[0041] S51. Assemble the core plate in the welding fixture to ensure that the inner circle of the core plate is concentric with the flow passage surface of the stator blade ring;

[0042] S52. Fix the core plate and the stator blade ring by spot welding;

[0043] S53. Inspect the quality of the solder joints, and no crack defects are required;

[0044] S54. Mark the electron beam welding track line;

[0045] S55. Wipe all surfaces of the stator blade ring and the welding fixture clean with alcohol or acetone;

[0046] S56. Assemble the welding fixture, check the position dimensions of the blades and the fixture, and fasten;

[0047] S57. After the assembly is completed, perform overall degaussing treatment, and the residual magnetism is required to be ≤2GS.

[0048] Preferably, the step S6 further includes the following steps:

[0049] S61. Place desiccants at positions avoiding the stator blade ring, and wrap the whole workpiece with plastic film;

[0050] S62. Pack for protection and wait for subsequent electron beam welding.

[0051] Therefore, the present invention has the following beneficial effects: (1) The present invention provides a method for assembling and welding a stator blade ring of an electron beam welded gas turbine compressor, which can ensure that the assembled and welded stator blade ring has a small assembly gap, precise dimensions, and extremely small welding deformation after electron beam welding; (2) Between each assembly step, the stator blades and the fixture are cleaned and degaussed, so as to ensure that the cleanliness and residual magnetism of the stator blade ring meet the requirements of electron beam welding. Description of the Drawings

[0052] Figure 1 is a structural schematic diagram of the stator blade ring in the present invention.

[0053] In the figure: 1, stator blade; 11, outer circle; 12, blade; 13, inner circle; 14, inner circle seam; 15, outer circle seam. Detailed Embodiment

[0054] The present invention will be further described below in conjunction with the drawings and the detailed embodiment.

[0055] In Figure 1 the embodiment shown, a method for assembling and welding a compressor stator vane ring by electron beam welding includes the following steps:

[0056] S1. Demagnetize the stator vanes and the corresponding tooling until the residual magnetism Br meets the requirements;

[0057] S2. Clean the stator vanes and the corresponding tooling until the cleanliness meets the requirements;

[0058] S3. Try to assemble and calculate the grinding amount for adjustment, and assemble into a stator vane ring;

[0059] S4. Use welding to fix the seams of the inner and outer circles of adjacent blades;

[0060] S5. Assemble the welding tooling and perform overall demagnetization treatment;

[0061] S6. Place desiccants, wrap with plastic film and then pack in a box to protect the assembled stator vane ring.

[0062] Among them, the stator vanes are divided into standard vanes and adjustment vanes. The quantity ratio of standard vanes and adjustment vanes can be adjusted according to the tolerance of stator vane processing. The adjustment vanes are even in number, with at least 2. The greater the tolerance of stator vane processing and the lower the dimensional accuracy of the stator vanes, the more adjustment vanes are selected; when multiple adjustment vanes are selected, several adjustment vanes are distributed as evenly as possible among the standard vanes. For example, when a stator vane ring composed of 2 adjustment vanes and 48 standard vanes is selected, one adjustment vane is set every 24 standard vanes. And if a stator vane ring composed of 4 adjustment vanes and 46 standard vanes is selected, then one adjustment vane is set at an interval of 11 standard vanes first, and then one adjustment vane is set at an interval of 12 standard vanes, and so on to set the adjustment vanes in a cycle; if there are multiple adjustment vanes, after calculating the grinding amount for adjustment vanes, it is evenly distributed to multiple adjustment vanes; through the as even as possible distribution of adjustment vanes, the error value of the blade radiation line is not easy to accumulate.

[0063] Among them, step S1 includes the following steps:

[0064] S11. Use a demagnetizer to demagnetize the stator vanes (including standard vanes and adjustment vanes) and the corresponding tooling;

[0065] S12. Measure the residual magnetism of the workpiece, and the qualified residual magnetism Br ≤ 2 GS.

[0066] Step S2 includes the following steps:

[0067] S21. Use ultrasonic or manual cleaning for the stator vanes and the corresponding tooling. Organic solvents can be used for ultrasonic cleaning, and gasoline can be used for manual cleaning;

[0068] S22. Use a white dust-free cloth dipped in alcohol or acetone to wipe the stator vanes and the corresponding tooling;

[0069] S23. Inspect the cleanliness. It is required to wipe the stationary blades and the corresponding tooling with a white dust-free cloth dipped in alcohol or acetone. The white dust-free cloth remains white and free of contamination as qualified.

[0070] S24. Wrap with plastic film in time to prevent contamination. During the above process, direct skin contact with the workpiece is prohibited.

[0071] Step S3 includes the following steps:

[0072] S31. Wipe the assembly table and other tooling clean with a dust-free cloth dipped in alcohol or acetone, and assemble while wearing clean white cotton gloves.

[0073] S32. Take 3 - 5 standard blades, inspect and adjust the radiation lines and the installation angles at each position shown in the drawing. After passing the inspection, fix them with wedge blocks, mark the corresponding positions on the table with a colored pen, and make the mark of the first blade.

[0074] S33. Assemble each standard blade and adjusting blade according to the drawing. Fix them with wedge blocks every 5 - 8 stationary blades, inspect the radiation lines of the stationary blades, and assemble them into a complete circle.

[0075] S34. When assembling the last stationary blade, measure the assembly gap, calculate the grinding allowance, and grind and adjust the assembly surface of the stationary blade.

[0076] S35. After the adjusting blade is ground and passes the trial assembly, demagnetize the adjusting blade. It is required that the residual magnetism Br ≤ 2 GS, and clean it thoroughly.

[0077] S36. Make marks on all adjusting blades on the radial end face of the outer circle of the stationary blade, make upper and lower marks at the split surface, mark the name of the stationary blade ring, etc.

[0078] S37. Wipe all stationary blades and tooling again with a dust-free cloth dipped in alcohol until the dust-free cloth remains white and free of contamination after wiping.

[0079] S38. Reassemble and fasten each stationary blade according to the drawing and the marks in steps S32, S33, and S36.

[0080] S39. Check the following assembly dimensions of the stationary blade: the blade installation angle α meets the drawing tolerance requirements; the axial step difference between adjacent stationary blades ≤ 0.5 mm; the radial step difference between adjacent stationary blades on the inner and outer shroud of the flow passage surface ≤ 0.5 mm; the joint of adjacent stationary blades is light-tight, most gaps cannot be inserted with a feeler gauge, and individual gaps are allowed and ≯ 0.20 mm.

[0081] S310. Wrap with plastic film in time to prevent the workpiece from being contaminated.

[0082] Among them, in step S34, the assembly clearance is measured by the measuring blade: Denote the intercept of the standard blade shroud as a, the intercept of the adjusted blade shroud as b, the intercept of the measuring blade shroud as c, and the number of adjusted blades as n. First, install the measuring blade at the position of the last stationary blade, and then try to insert feeler gauges of different thicknesses between the measuring blade and the first blade. The thickness dimension of the feeler gauge with the largest thickness that can be successfully inserted between the measuring blade and the first blade is denoted as △s, and the grinding amount of the adjusted blade is denoted as △t. Then, the grinding allowance of the adjusted blade can be obtained: △t = b - a - (c + △s - a) / n, where the intercept refers to the chord length of the blade shroud on the specified pitch circle.

[0083] Step S4 further includes the following steps:

[0084] S41. On the butt joints of the inner and outer circles of adjacent blades, use argon arc welding or laser welding. First, spot weld and then weld the stationary blade ring firmly; control the welding heat input to ensure a shallow penetration depth.

[0085] S42. Check the weld reinforcement height and width, and check for weld defects.

[0086] S43. Wrap the plastic film in time to prevent the workpiece from being contaminated.

[0087] Step S5 also includes the following steps:

[0088] S51. Assemble the core plate to ensure that the inner circle of the core plate is concentric with the flow passage surface of the stationary blade ring.

[0089] S52. Spot weld and fix the core plate and the stationary blade ring on both the front and back sides.

[0090] S53. Inspect the quality of the weld spots, and require no crack defects.

[0091] S54. Mark the electron beam welding track line.

[0092] S55. Wipe all surfaces of the stationary blade ring and the welding tooling clean with a lint-free cloth dipped in alcohol.

[0093] S56. Assemble the welding tooling, check the position dimensions of the blade and the tooling, and tighten.

[0094] S57. After the assembly is completed, perform overall demagnetization treatment, and require the residual magnetism ≤ 2 GS.

[0095] S58. Wrap the plastic film in time to prevent the workpiece from being contaminated.

[0096] Step S6 also includes the following steps:

[0097] S61. Place desiccants at positions avoiding the stationary blade ring, and wrap the entire workpiece with plastic film.

[0098] S62. Pack and protect, waiting for subsequent electron beam welding.

Claims

1. A method for assembling and welding the static blade ring of a gas turbine compressor by electron beam welding, characterized in that It includes the following steps: S1. Demagnetize the stationary blades and the corresponding tooling until the residual magnetism meets the requirements; S2. Clean the stationary blades and the corresponding tooling until the cleanliness meets the requirements. Among them, the stationary blades include standard blades and adjusting blades; S3. Try to assemble and calculate the grinding amount of the adjusting blades according to the gap generated during assembly, and assemble the standard blades and adjusting blades into a stationary blade ring; S4. Use welding to fix the seams of the inner and outer circles of adjacent blades; S5. Assemble the welding tooling and conduct overall demagnetization treatment; S6. Place desiccants, wrap them with plastic film and then pack them in boxes to protect the assembled stationary blade ring; In step S3, the assembly gap is also measured through a measuring blade. First, install the measuring blade at the position of the last stationary blade, and then try to insert feeler gauges of different thicknesses between the measuring blade and the first blade. Record the thickness dimension of the feeler gauge with the largest thickness that can be successfully inserted between the measuring blade and the first blade as △s, and calculate the grinding amount of the adjusting blade; Check the following assembly dimensions of the stationary blades: the axial step difference between adjacent stationary blades ≤ 0.5 mm; the radial step difference between adjacent stationary blades on the inner and outer shroud of the flow passage surface ≤ 0.5 mm; the seams between adjacent stationary blades are light-tight.

2. A method for assembling and welding a compressor stator vane ring of a gas turbine by electron beam welding according to claim 1, characterized in that The following steps are also included in step S1: S11. Use a demagnetizer to demagnetize the stationary blades and the corresponding tooling; S12. Measure the residual magnetism of the workpiece. The qualified residual magnetism Br ≤ 2 GS.

3. A method for welding and assembling the static blade ring of a gas turbine compressor by electron beam welding according to claim 1, characterized in that The following steps are also included in step S2: S21. Clean the stationary blades and the corresponding tooling; S22. Wipe the stationary blades and the corresponding tooling with alcohol or acetone; S23. Inspect the cleanliness; S24. Wrap with plastic film in time to prevent the stationary blades and the corresponding tooling from being contaminated.

4. A method for assembling and welding a compressor stator vane ring of a gas turbine by electron beam welding according to claim 1, characterized in that The following steps are also included in step S3: S31. Wipe the assembly table clean with alcohol or acetone and use clean gloves for assembly; S32. Take 3 - 5 standard blades, conduct pilot assembly through the welding tooling, check whether the radiation lines of the blades are aligned with those shown in the drawing, make alignment adjustments, and mark the standard blade as the first blade; S33. Assemble each standard blade and adjusting blade according to the design drawing. Every 5 - 8 stationary blades, fix the stationary blades on the corresponding tooling through wedge blocks; S34. When assembling to the last stationary blade, measure the assembly gap, calculate the grinding allowance, and grind the assembly surface of the adjusting blade according to the grinding allowance; S35. After the grinding of the adjusting blade is completed and the trial assembly is qualified, demagnetize the adjusting blade, with the requirement that the residual magnetism Br ≤ 2 GS, and clean it; S36. Mark all the adjusting blades; S37. Wipe all the stationary blades and tooling with alcohol or acetone again; S38. Re - assemble and fasten each standard blade and adjusting blade according to steps S32 and S33, and install the last stationary blade; S39. Wrap with plastic film in time to prevent the workpiece from being contaminated.

5. A method for assembling and welding a compressor stator vane ring of a gas turbine by electron beam welding, characterized in that, The following steps are also included in step S4: S41. Weld the stationary blades into a stationary blade ring on the seams of the inner and outer circles of adjacent stationary blades; S42. Check the weld defects; S43. Wrap with plastic film in time to prevent the workpiece from being contaminated.

6. The method for assembling and welding the static blade ring of a gas turbine by electron beam welding according to claim 1, characterized in that, The following steps are also included in step S5: S51. Assemble the core plate in the welding tooling to ensure that the inner circle of the core plate is concentric with the flow passage surface of the stationary blade ring; S52. Fix the core plate and the stationary blade ring by spot welding; S53. Inspect the quality of the solder joints, and there should be no crack defects; S54. Mark the electron beam welding track line; S55. Wipe all surfaces of the stator vane ring and the welding tooling clean with alcohol or acetone; S56. Assemble the welding tooling, check the position and dimension of the blade and the tooling, and fasten them; S57. After the assembly is completed, perform overall demagnetization treatment, and the residual magnetism should be ≤ 2 GS; S58. Wrap the plastic film in time to prevent the workpiece from being contaminated.

7. A method for assembling and welding a compressor stator vane ring of a gas turbine by electron beam welding according to claim 1, characterized in that, The following steps are also included in the said step S6: S61. Place desiccants at a position avoiding the stator vane ring, and wrap the whole workpiece with plastic film; S62. Pack and protect it for subsequent electron beam welding.

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