CN115958377A - Tip repairing method for gas turbine single crystal high-temperature alloy turbine rotor blade - Google Patents
Tip repairing method for gas turbine single crystal high-temperature alloy turbine rotor blade Download PDFInfo
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- CN115958377A CN115958377A CN202211738369.3A CN202211738369A CN115958377A CN 115958377 A CN115958377 A CN 115958377A CN 202211738369 A CN202211738369 A CN 202211738369A CN 115958377 A CN115958377 A CN 115958377A
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Abstract
The invention discloses a gas turbine monocrystal superalloy turbine rotor blade tip repairing method, which belongs to the technical field of rotor blade tip repairing, and adopts a fast-frequency pulse mode of a direct-current fast-frequency pulse welding machine, so that heat input in a repairing process is reduced, and tissue recrystallization is avoided; the used directional solidification high-temperature alloy welding wire ensures that the tensile strength and the high-temperature durability of the welding wire reach more than 85 percent of that of single crystal DD5, and the mode of blade tenon water cooling and blade tip heating is used, so that on one hand, the growth direction of a build-up welding tissue is ensured to be parallel to the <001> orientation, the transverse crystal boundary vertical to the stress axis direction is eliminated, meanwhile, the formation of large orientation difference crystal grains and mixed crystals is avoided, and the thermal fatigue resistance of the whole blade is ensured. On the other hand, the surfacing layer of the blade tip is in a high-temperature state, so that the residual stress is effectively reduced, and the service life of the blade is prolonged.
Description
Technical Field
The invention belongs to the technical field of rotor blade tip repair, and particularly relates to a method for repairing a blade tip of a gas turbine single crystal high-temperature alloy turbine rotor blade.
Background
The single crystal blade is a key technology and a part of a modern aeroengine, an important index of the aeroengine is the temperature before a turbine, the higher the index is, the larger the thrust of the engine is, but the temperature of gas coming out of a combustion chamber reaches thousands of degrees and exceeds the melting point of steel, and under the impact of the high-temperature, high-speed and high-pressure gas, the high-pressure turbine also needs to rotate at high speed to drive a high-pressure compressor, so that the requirements on materials and processes are extremely high, the single crystal blade is the most ideal material of the high-pressure turbine blade, the single crystal blade is a blade with only one crystal material, and the grain boundary is parallel to the stress direction, so that cavities and cracks are eliminated, the blade can resist the gas impact of the engine, and the reliability is higher, so the single crystal blade becomes a mainstream material of the high-pressure turbine blade of the modern aeroengine.
Aeroengines and ground gas turbines are known as "crown" in modern industry and are one of the important signs of national comprehensive strength. The turbine blade is the first key part because of being in the parts with highest temperature, most complex stress and most severe environment, and is known as the bright pearl on the crown.
Since gas turbine OEMs (original manufacturers) monopolize turbine blade repair techniques, they can only be sent to the OEMs for repair. Complete foreign dependency results in uncontrolled cycle time, cost, and consequent maintenance cycle risk (and substantial foreign exchange expenditure). Accordingly, advanced, reliable repair techniques are urgently needed to repair locally damaged turbine rotor blades and the like.
Because the service environment is harsh, the single crystal blade is easily subjected to local damage including abrasion, crack, ablation and the like of the blade tip, and the development of a reliable blade repairing technology is important for prolonging the service life of an aeroengine and reducing the cost. The single crystal blade has a value of 30-80 ten thousand yuan, and a special process is needed for repairing the single crystal blade, so that the performance of a repaired part is guaranteed, large-angle crystal boundaries and mixed crystals are easy to appear, and cracks are easy to appear in the service process. On the other hand, the high-temperature performance is reduced to prevent the blade matrix from recrystallization, so that the selection of the repair material and the heat input control in the repair process need to be strictly controlled.
Disclosure of Invention
The invention aims to solve the technical problem of providing a gas turbine monocrystal superalloy turbine rotor blade tip repairing method aiming at the defects of the background art, which uses a fast frequency pulse mode of a direct current fast frequency pulse welding machine, reduces heat input in the repairing process, avoids the occurrence of tissue recrystallization, uses a directional solidification superalloy welding wire, ensures that the tensile strength and the high-temperature durability reach 85 percent of single crystal DD5, adopts blade tenon water cooling and blade tip preheating, on one hand, avoids the generation of cracks at the repaired part, on the other hand, ensures that the growth direction of the tissue is parallel to the <001> direction, and forms a directional solidification tissue.
The invention adopts the following technical scheme for solving the technical problems:
a method for repairing the blade tip of a gas turbine single crystal superalloy turbine rotor blade specifically comprises the following steps:
step 1, checking and recording the blades: inspecting and recording the types, the number, the sizes and the positions of defects such as cracks, abrasion, ablation, pits and the like of the blade;
step 2, size inspection, flow test and weighing of the blades: scanning or detecting the blades one by adopting a three-dimensional optical scanner or a three-coordinate measuring instrument, and recording the size deviation of the blade tip; measuring the flow of each blade and each cooling channel, wherein the flow of the blade before repair meets the requirement of 7 +/-1L/min, if not, checking whether the air film hole is blocked, and if so, dredging;
step 3, sand blowing and cleaning:
step 3.1, carrying out dry powder sand blasting treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand, removing a carbon deposit layer and an oxidation film on the surface until the carbon deposit layer and the oxidation film on the surface are completely removed, wherein the sand blasting time of the same part is not more than 1min, removing sand dust on the surface of the blade by using compressed air after the blade is subjected to sand blasting, and checking the appearance;
step 3.2, immersing the leaves into 3-5% water-based degreasing agent (mass ratio) water solution, cleaning for 5-10 min by using an ultrasonic cleaning machine, and then washing with flowing cold water;
step 3.3, placing the cleaned leaves in a drying box for drying, wherein the drying temperature is 60-100 ℃, and the drying process time is 20-60 min;
and 4, step 4: removing the blade coating;
step 4.1, coating the protective agent on the tenon parts of the blades without the coating by using a brush;
step 4.2, immersing the leaves into an acidic solution added with a corrosion inhibitor, checking the falling condition of the surface coating of the leaves every 10min, neutralizing the coating by using an alkaline solution after the coating completely falls off, washing the neutralized coating by using running water and drying the neutralized coating by blowing;
step 4.3, finally, placing the single crystal blade in a drying oven for drying at the temperature of 60-100 ℃ for 30-60 min;
step 4.4, removing the protective agent by using acetone to remove the tenon, and then carrying out dry powder sand blasting treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand;
and 5: and (3) defect inspection: inspecting the surface of the blade by using a 3-5 times magnifier, performing fluorescence inspection according to HB/Z61, and marking cracks, lengths and positions; repairing the blade tips and the wing profile parts which are adjacent and higher than the cover plate by 1mm and have cracks, ablation and the like by repair welding, discarding the cracks at the rest positions, and polishing the area to be welded before welding;
step 6: surfacing of the blade tip:
step 6.1, using a tenon water-cooling fixing tool which is a machining and detection tool, performing extraction and insertion type fixing on the tenon of the single crystal blade, wherein the water flow of a flow channel in the tenon water-cooling fixing tool is 5-10L/min, the blade tip is heated by using an induction heating device with a conformal copper pipe coil, the distance between the coil and the blade tip is 5-10mm, and the temperature at the blade tip is 450-550 ℃ (temperature measurement control by an infrared temperature control gun);
step 6.2, carrying out argon arc welding surfacing for 5-10s after preheating to the temperature, wherein the equipment uses a direct-current fast frequency pulse welding machine, the diameter of a tungsten electrode is 1.2-1.6 mm, the diameter of a nozzle is 8mm, and the welding mode is as follows: a fast frequency secondary pulse mode, wherein the fast frequency current is 20-30A, the frequency f =20000Hz, the main current =30A, the duration time is 0.1s, the auxiliary current is 10A, the duration time is 0.01-0.05 s, and the argon flow is 10-12L/min; the width of the blade tip of the blade is 0.8-2.0 mm, the defect height of the blade tip is 1-2 mm, and the height of the surfacing welding is 3-4 mm; after surfacing, closing the water flow, controlling the temperature of the induction heating device to be reduced by 20 ℃/min, and closing the induction heating device when the temperature is reduced to 100 ℃;
step 7, stress relief annealing: heating to 950-1050 ℃ by using a vacuum heat treatment furnace under the condition that the vacuum degree is better than 10Pa, preserving heat for 1h, and rapidly cooling to room temperature by using argon;
step 8, carrying out nondestructive detection on the blade tip overlaying part and the nearby area, wherein the nondestructive detection comprises visual detection, X-ray detection and fluorescence detection; if the blade tip is unqualified, returning to the step six for repair welding until the blade tip weld-up part is free of defects, and performing repair welding on the same weld-up part for no more than 3 times; step 9, processing the blade tip profile: fixing and positioning the blade by using a tool, then machining the blade tip of the blade after surfacing by using a numerical control machine according to the digital analogy of the blade, and reserving a margin of 0.2mm on two sides of the blade tip; after machining, polishing and repairing the blade tip by using tools such as files, oilstones and the like, wherein the finally machined blade tip profile is smooth and smooth with the original wing profile;
step 10, restoring the coating: recovering the coating on the surface of the blade, wherein the thickness of the coating is 30-70 mu m;
step 11, final inspection: including visual inspection, dimensional inspection, weighing inspection, flow inspection, fluoroscopy.
As a further preferred scheme of the gas turbine single crystal superalloy turbine rotor blade tip repairing method, in step 6, the blade material is DD5 single crystal, the welding wire is directional solidification superalloy, and the components are as follows: c0.08-0.15, cr6.00-7.50, co 11.00-12.00, W4.50-5.00, mo 1.00-2.00, al 5.00-6.00, ta6.00-6.50, re 2.50-3.50, hf 1.30-1.70, B0.01-0.02, ni 60.00-65.00.
As a further preferable scheme of the tip repairing method of the gas turbine single crystal superalloy turbine rotor blade, ta has the following functions: promote Cr to dissolve into a gamma-phase matrix, cause lattice distortion, improve the strength of a solid solution, improve the oxidation resistance and the high-temperature corrosion resistance of the nickel-based superalloy, and simultaneously resist tensile strength and yield strength;
cr: simultaneously combine with O to form Cr 2 O 3 High temperature and corrosion resistance;
co: the solubility of Cr, mo, W and C in a gamma-phase matrix is increased, the carbide morphology at a crystal boundary is improved, the crystal boundary is strengthened, and meanwhile, the solid solution strengthening is realized, and the hot corrosion resistance is improved;
the function of C: strengthening elements between dendrites and grain boundaries to form discontinuous granular carbides, such as MC, M7C3, M6C, M23C6 and the like, so as to prevent the grain boundary from sliding;
the function of Re: the content of the refined structure of the gamma' phase is controlled to be 2.5-3.5%, the durability of the high-temperature alloy is improved, the TCP phase is separated out due to overhigh content, and the durability is seriously reduced;
the function of Ni: the stable elements of the austenite phase form solid solutions with elements such as Cr, co, mo, al, C, B and the like, and the O-affinity promotes the formation of oxide films;
the role of W: obvious lattice expansion is caused, a long-range stress field is formed, dislocation motion is prevented, and therefore yield strength is improved;
the function of Mo: the effect is basically consistent with that of W, solid solution strengthening is performed, the passivation and anti-reduction capability of the alloy is improved, but the content needs to be controlled below 2%, and tissue segregation is easily caused due to overhigh content;
the function of B: microalloying elements are enriched at the grain boundary, so that the precipitation of harmful phases at the grain boundary is eliminated, and the durability and the creep property are improved;
the function of Al: the gamma' -Ni3Al is generated with Ni, so that the strength is improved, and the oxidation resistance and the corrosion resistance are improved;
the function of Hf: the high-temperature durable plasticity of the high-temperature alloy is improved, the high-temperature notch sensitivity is eliminated, the number of gamma' is increased, and the stability of MC type carbide is improved.
As a further preferred scheme of the tip repairing method of the gas turbine single crystal superalloy turbine rotor blade, the tip tissues are all small-angle grain boundaries after surfacing, wherein the phase difference of adjacent grains is less than 10 degrees, and no mixed crystal exists; the hardness of the overlaying layer is 460HV-475HV, the DD5 matrix is about 440HV, the room temperature performance tensile strength of the joint tensile sample reaches more than 90% of that of the DD5 matrix and is 900-950MPa, and the high temperature endurance performance is more than 85% of that of the DD5 matrix.
As a further preferable scheme of the method for repairing the blade tip of the single crystal superalloy turbine rotor blade of the combustion engine, in step 6,
a tenon water-cooling fixing tool is a machining and detecting tool, is formed by printing through a laser selective melting forming technology, is made of GH4169, and then performs mechanical machining on a tenon matching surface of a tenon to ensure that the positioning precision is 0.01mm, and the diameter of an inner runner is phi 6mm.
As a further preferred scheme of the method for repairing the blade tip of the single crystal superalloy turbine rotor blade of the combustion engine, in step 11,
visual inspection: the surface of the blade is not allowed to be collided or scratched; the surface of the coating is not allowed to have the defects of warping, bubbling, cracking and the like, and the tenon area is not coated; visual inspection and probe inspection are carried out on the air film holes on the exhaust edge of the blade piece by piece, and the air film holes are not allowed to be blocked;
and (4) checking the size: measuring the profile degree of the blade tip profile of the repaired part by using a detection tool and a three-coordinate measuring instrument, wherein the deviation is qualified when the deviation is +/-0.1 mm;
weighing and checking: the weight deviation of the new part is +/-5 g, and the new part is qualified;
and (3) flow inspection: the flow of the main channel is qualified after 6-8L/min;
and (3) fluorescence examination: the fluorescence examination was carried out at HB/Z61, and cracks, pores, inclusions and unfused defects were not allowed.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
1. the invention uses the fast frequency pulse mode of the direct current fast frequency pulse welding machine, reduces the heat input in the repair process, and avoids the occurrence of tissue recrystallization;
2. the directional solidification high-temperature alloy welding wire used in the invention ensures that the tensile strength and the high-temperature durability reach 85 percent of single crystal DD 5;
3. the invention uses the modes of water cooling of the blade tenon and heating of the blade tip, on one hand, the growth direction of the overlaying welding structure is ensured to be parallel to the <001> orientation, the transverse crystal boundary vertical to the stress axis direction is eliminated, and simultaneously, the formation of large orientation difference crystal grains and mixed crystals is avoided, and the thermal fatigue resistance of the whole blade is ensured; on the other hand, the surfacing layer of the blade tip is in a high-temperature state, so that the residual stress is effectively reduced, and the service life of the blade is prolonged.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a schematic view of a single crystal superalloy turbine rotor blade and a water-cooled fixture and heating of the present invention;
FIG. 2 is a schematic view of a tenon water-cooling fixing tool (both machining and detection tools) of the invention;
FIG. 3 is a schematic view of an inner runner of the tenon water-cooling fixing tool of the invention;
FIG. 4 is a post-build-up profile of the blade tip of the present invention
FIG. 5 is a schematic view of the machined topography of the blade tip of the present invention;
FIG. 6 is a schematic view of a directionally solidified structure (hypo-and hyper-power) of a single crystal superalloy turbine rotor blade tip build-up weld of the present invention.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the attached drawings:
in order to make the objects, 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 with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
Example one
As shown in fig. 1 to 6, a method for repairing a blade tip of a gas turbine single crystal superalloy turbine rotor blade comprises the following steps:
step 1: and (5) inspecting and recording the blades. Inspecting and recording the types, the number, the sizes and the positions of defects such as cracks, abrasion, ablation, pits and the like of the blade;
step 2: size checking of the blades, flow testing and weighing. And scanning the blades one by adopting a three-dimensional optical scanner, and recording the size deviation of the blade tip and the defect of the blade tip by 1.8mm. Measuring the flow of the blade and each cooling channel, wherein the flow of the blade before repair is 7.7L/min;
and step 3: and (2) blowing sand and cleaning, namely performing dry powder blowing sand treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand, removing a carbon deposit layer and an oxidation film on the surface until the carbon deposit layer and the oxidation film on the surface are completely removed, blowing sand at the same position for not more than 1min, removing sand dust on the surface of the blade by using compressed air after the blade is blown sand, and checking the appearance. Immersing the leaves into 3-5% water-based degreasing agent (mass ratio) water solution, cleaning for 5-10 min by an ultrasonic cleaning machine, and then washing with flowing cold water. Drying the cleaned leaves in a drying box at the drying temperature of 60-100 ℃ for 20-60 min;
and 4, step 4: and removing the blade coating. Coating a protective agent on the tenon part of the blade without the coating by using a brush; immersing the leaves into an acidic solution added with a corrosion inhibitor, checking the falling condition of the surface coating of the leaves every 10min, neutralizing the leaves with an alkaline solution after the coating falls off completely, and then washing and drying the leaves with running water; finally, placing the single crystal leaves in a drying oven for drying at the temperature of 60-100 ℃ for 30-60 min; removing the tenon by using acetone to remove the protective agent, and then performing dry powder sand blasting treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand;
and 5: and (6) defect inspection. Inspecting the surface of the blade by using a 3-5 times magnifying glass, performing fluorescence inspection according to HB/Z61, and marking cracks, lengths and positions. Allowing surfacing repair to crack, ablation and the like at the blade tip and the adjacent airfoil surface part 1mm higher than the cover plate, discarding the cracks at the rest positions, and polishing the area to be surfaced before surfacing;
step 6: and (4) surfacing of the blade tip. The device shown in the figure 1 is adopted to fix the tenon of the single crystal blade of the gas turbine in a pulling and inserting way, the water flow of a flow channel in the tenon water-cooling fixing tool is 5-10L/min, the blade tip is heated by an induction heating device with a conformal copper pipe coil, the distance between the coil and the blade tip is 5-10mm, and the temperature at the blade tip is 450-550 ℃ (temperature measurement control by an infrared temperature control gun); preheating to the temperature for 5-10s, carrying out argon arc welding surfacing, wherein the equipment uses a direct-current fast-frequency pulse welding machine, the diameter of a tungsten electrode is 1.2-1.6 mm, the diameter of a nozzle is 8mm, and the welding mode is as follows: the device comprises a fast frequency secondary pulse mode, wherein the fast frequency current is 20-30A, the frequency f =20000Hz, the main current =30A, the duration time is 0.1s, the auxiliary current is 10A, the duration time is 0.01-0.05 s, and the argon flow is 10L/min-12L/min. The width of the blade tip of the blade is 0.8-2.0 mm, the defect height of the blade tip is 1.8mm, and the height of the surfacing is 3.5mm. After surfacing, closing the water flow, controlling the temperature of the induction heating device to be reduced by 20 ℃/min, and closing the induction heating device when the temperature is reduced to 100 ℃;
as shown in fig. 6, the blade material is DD5 single crystal, and the welding wire is directionally solidified high temperature alloy, which has the following components: 0.10% of C, 6.50% of Cr6, 11.00% of Co, 5.00% of W, 1.50% of Mo, 5.20% of Al, 6.48% of Ta, 2.8% of Re, 1.5% of Hf, 0.01% of B and 60.91% of Ni.
The tip structure after build-up welding is shown in fig. 5, and the structures are all small-angle grain boundaries (the phase difference of adjacent grains is less than 10 degrees) and have no mixed crystal. The hardness of the surfacing layer is about 470HV, the DD5 matrix is 440HV, the room-temperature performance tensile strength of the joint tensile sample reaches 92 percent of that of the DD5 matrix and is 920MPa, and the high-temperature durability of the joint tensile sample is 87 percent of that of the DD5 matrix.
And 7: and (5) stress relief annealing. Heating to 1000 +/-10 ℃ by using a vacuum heat treatment furnace under the condition that the vacuum degree is better than 10Pa, preserving heat for 1h, and rapidly cooling to room temperature by using argon;
and 8: and carrying out nondestructive detection on the blade tip overlaying part and the nearby area, wherein the nondestructive detection comprises visual detection, X-ray detection and fluorescence detection. If the blade tip is unqualified, returning to the step six for repair welding until the blade tip weld-up part is free of defects, and performing repair welding on the same weld-up part for no more than 3 times; visual detection: the defects of meat deficiency, cracks, air holes and the like are avoided; x-ray detection: according to HB/Z60, defects such as cracks, inclusions, unfused and the like are not allowed; the fluorescence examination was carried out at HB/Z61, and defects such as cracks, pores, inclusions, and lack of fusion were not allowed.
And step 9: and (4) processing a blade tip profile. The tool shown in fig. 2 is used for fixing and positioning the blade, then a numerical control machine tool is used for machining the blade tip of the blade after surfacing according to the digital-analog mode of the blade, and the allowance of 0.2mm is reserved on the two sides of the blade tip. After machining, polishing and repairing the blade tip by using tools such as files, oilstones and the like, wherein the finally machined blade tip profile is smooth and smooth with the original wing profile;
step 10: and (6) recovering the coating. Recovering the coating on the surface of the blade, wherein the thickness of the coating is 30-50 mu m;
step 11: and (5) final inspection. Including visual inspection, dimensional inspection, weighing inspection, flow inspection, fluoroscopy.
Visual inspection: the surface of the blade is not allowed to be collided or scratched; the surface of the coating is not allowed to have the defects of warping, bubbling, cracking and the like, and the tenon area is not coated; visual inspection and probe inspection are carried out on the air film holes on the exhaust edge of the blade piece by piece, and the air film holes are not allowed to be blocked;
checking the size: using the detection tool shown in FIG. 2, and then measuring the profile degree of the tip profile of the repaired part by using a three-coordinate measuring instrument, wherein the deviation is qualified as +/-0.06 mm;
weighing and checking: the weight deviation of the new piece is 1.5g, and the new piece is qualified;
and (3) flow inspection: the flow rate of the main channel is 7.5L/min, and the main channel is qualified;
and (3) fluorescence examination: the fluorescence examination was carried out at HB/Z61, and defects such as cracks, pores, inclusions, lack of fusion, etc. were not observed.
Step 12: and packaging and delivering.
Example two
A method for repairing the blade tip of a gas turbine single crystal superalloy turbine rotor blade comprises the following steps:
step 1: and (5) inspecting and recording the blade. Inspecting and recording the types, the number, the sizes and the positions of defects such as cracks, abrasion, ablation, pits and the like of the blade;
step 2: size checking of the blades, flow testing and weighing. And scanning or detecting the blade by using a three-coordinate measuring instrument, and recording the size deviation of the blade tip, wherein the defect height of the blade tip is about 1.4mm. Measuring the flow of the blade and each cooling channel, wherein the flow of the blade before repair meets 7.1L/min;
and step 3: and (2) blowing sand and cleaning, namely performing dry powder blowing sand treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand, removing a carbon deposit layer and an oxidation film on the surface until the carbon deposit layer and the oxidation film on the surface are completely removed, blowing sand at the same position for not more than 1min, removing sand dust on the surface of the blade by using compressed air after the blade is blown sand, and checking the appearance. Immersing the leaves into 3-5% water-based degreasing agent (mass ratio) water solution, cleaning for 5-10 min by an ultrasonic cleaning machine, and then washing with flowing cold water. Drying the cleaned leaves in a drying box at the drying temperature of 60-100 ℃ for 20-60 min;
and 4, step 4: and removing the blade coating. Coating a protective agent on the tenon part of the blade without the coating by using a brush; immersing the leaves into an acidic solution added with a corrosion inhibitor, checking the falling condition of the surface coating of the leaves every 10min, neutralizing the leaves with an alkaline solution after the coating falls off completely, and then washing and drying the leaves with running water; finally, placing the single crystal blade in a drying oven for drying at the temperature of 60-100 ℃ for 30-60 min; removing the protective agent by acetone, and then carrying out dry powder sand blasting treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand;
and 5: and (6) defect inspection. Inspecting the surface of the blade by using a 3-5 times magnifying glass, performing fluorescence inspection according to HB/Z61, and marking cracks, lengths and positions. Performing repair welding repair on the blade tip and the adjacent airfoil surface part which is 1mm higher than the cover plate and has cracks, ablation and the like, discarding the remaining parts with cracks, and polishing the region of the blade tip to be subjected to surfacing before surfacing;
step 6: and (4) surfacing of the blade tip. The device shown in the figure 1 is adopted to fix the tenon of the single crystal blade of the gas turbine in a pulling and inserting way, the water flow of a flow channel in the tenon water-cooling fixing tool is 5-10L/min, the blade tip is heated by an induction heating device with a conformal copper pipe coil, the distance between the coil and the blade tip is 5-10mm, and the temperature at the blade tip is 450-550 ℃ (temperature measurement control by an infrared temperature control gun); preheating to the temperature, performing argon arc welding surfacing for 5-10s, wherein the equipment uses a direct-current fast frequency pulse welding machine, the diameter of a tungsten electrode is 1.2-1.6 mm, the diameter of a nozzle is 8mm, and the welding mode is as follows: the device comprises a fast frequency secondary pulse mode, wherein the fast frequency current is 20-30A, the frequency f =20000Hz, the main current =30A, the duration time is 0.1s, the auxiliary current is 10A, the duration time is 0.01-0.05 s, and the argon flow is 10L/min-12L/min. The height of the surfacing welding is 3.0mm. After surfacing, closing the water flow, controlling the temperature of the induction heating device to be reduced by 20 ℃/min, and closing the induction heating device when the temperature is reduced to 100 ℃;
wherein the blade material is DD5 single crystal, and the welding wire is directional solidification superalloy, its composition: 0.12 percent of C, 6.30 percent of Cr, 11.50 percent of Co11, 4.50 percent of W, 1.50 percent of Mo, 5.20 percent of Al, 6.48 percent of Ta, 3.2 percent of Re, 1.3 percent of Hf, 0.01 percent of B and 60.71 percent of Ni.
The structure of the tip after overlaying is shown in fig. 5, the structure is a small angle grain boundary (the phase difference of adjacent grains is less than 10 degrees), and the structure has no mixed crystal. The hardness of the overlaying layer is about 465HV, the DD5 matrix is 440HV, the room-temperature performance tensile strength of the joint tensile sample reaches 91 percent of that of the DD5 matrix and is 910MPa, and the high-temperature durability of the joint tensile sample is 86 percent of that of the DD5 matrix.
And 7: and (5) stress relief annealing. Heating to 1020 +/-10 ℃ by using a vacuum heat treatment furnace under the condition that the vacuum degree is better than 10Pa, preserving heat for 1h, and quickly cooling to room temperature by using argon;
and step 8: and carrying out nondestructive testing on the blade tip overlaying part and the nearby area, wherein the nondestructive testing comprises visual testing, X-ray testing and fluorescence testing. If the blade tip is unqualified, returning to the step six for repair welding until the blade tip weld-up part is free of defects, and performing repair welding on the same weld-up part for no more than 3 times; visual detection: the defects of meat deficiency, cracks, air holes and the like are avoided; and (3) X-ray detection: according to HB/Z60, defects such as cracks, inclusions, unfused and the like are not allowed; the fluorescent inspection was carried out according to HB/Z61, and defects such as cracks, pores, inclusions, lack of fusion and the like were not observed.
And step 9: and (4) processing a blade tip profile. The tool shown in fig. 2 is used for fixing and positioning the blade, then a numerical control machine tool is used for machining the blade tip of the blade after surfacing according to the digital-analog mode of the blade, and the allowance of 0.2mm is reserved on the two sides of the blade tip. After machining, polishing and repairing the blade tip by using tools such as files, oilstones and the like, wherein the finally machined blade tip profile is smooth and smooth with the original wing profile;
step 10: and (6) recovering the coating. Recovering the coating on the surface of the blade, wherein the thickness of the coating is 30-70 mu m;
step 11: and (5) final inspection. Including visual inspection, dimensional inspection, weighing inspection, flow inspection, fluoroscopy.
Visual inspection: the surface of the blade is not allowed to be collided or scratched; the surface of the coating is not allowed to have defects of warping, bubbling, cracking and the like, and the tenon area is not coated; visual inspection and probe inspection are carried out on the air film holes on the exhaust edge of the blade piece by piece, and the air film holes are not allowed to be blocked;
and (4) checking the size: using the detection tool shown in FIG. 2, and then measuring the profile degree of the tip profile of the repaired part by using a three-coordinate measuring instrument, wherein the deviation is qualified as +/-0.05 mm;
weighing and checking: the weight deviation of the new part is 1.2g, and the new part is qualified;
flow checking: the flow rate of the main channel is 7.2L/min, and the main channel is qualified;
and (3) fluorescence examination: the fluorescence examination was carried out at HB/Z61, and defects such as cracks, pores, inclusions, lack of fusion, etc. were not observed.
Step 12: and packaging and delivering.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention. While the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.
Claims (6)
1. A gas turbine single crystal superalloy turbine rotor blade tip repair method is characterized in that: the method specifically comprises the following steps:
step 1, checking and recording the blades: inspecting and recording the types, the number, the sizes and the positions of defects such as cracks, abrasion, ablation, pits and the like of the blade;
step 2, size inspection, flow test and weighing of the blades: scanning or detecting the blades one by adopting a three-dimensional optical scanner or a three-coordinate measuring instrument, and recording the size deviation of the blade tips; measuring the flow of each blade and each cooling channel, wherein the flow of the blade before repair meets the requirement of 7 +/-1L/min, if not, checking whether a gas film hole is blocked, and if so, dredging;
step 3, sand blowing and cleaning:
step 3.1, carrying out dry powder sand blasting treatment on the surface of the single crystal blade by using 60-120 meshes of quartz sand or corundum sand, removing a carbon deposit layer and an oxidation film on the surface until the carbon deposit layer and the oxidation film on the surface are completely removed, wherein the sand blasting time of the same part is not more than 1min, removing sand dust on the surface of the blade by using compressed air after the blade is subjected to sand blasting, and checking the appearance;
step 3.2, immersing the blades into 3-5% water-based degreasing agent (mass ratio) aqueous solution, cleaning for 5-10 min by using an ultrasonic cleaning machine, and then washing with flowing cold water;
step 3.3, drying the cleaned leaves in a drying box at the temperature of 60-100 ℃ for 20-60 min;
and 4, step 4: removing the blade coating;
step 4.1, coating the protective agent on the tenon parts of the blades without the coating by using a brush;
step 4.2, immersing the leaves into an acidic solution added with a corrosion inhibitor, checking the falling condition of the surface coating of the leaves every 10min, neutralizing the leaves with an alkaline solution after the leaves completely fall off, and then washing and drying the leaves with running water;
step 4.3, finally, placing the single crystal leaves in a drying oven for drying at the temperature of 60-100 ℃ for 30-60 min;
step 4.4, removing the tenon by using acetone to remove the protective agent, and then performing dry powder sand blasting treatment on the surface of the single crystal blade by using quartz sand or corundum sand with 60-120 meshes;
and 5: and (3) defect inspection: inspecting the surface of the blade by using a 3-5 times magnifier, performing fluorescence inspection according to HB/Z61, and marking cracks, lengths and positions; performing repair welding repair on the blade tip and the part of the airfoil surface which is adjacent and is 1mm higher than the cover plate and has cracks, ablation and the like, discarding the remaining parts with cracks, and polishing the area to be subjected to surfacing welding before surfacing welding;
and 6: and (3) tip surfacing:
step 6.1, using a tenon water-cooling fixing tool which is a machining and detection tool, performing extraction and insertion type fixing on the tenon of the single crystal blade, wherein the water flow of a flow channel in the tenon water-cooling fixing tool is 5-10L/min, the blade tip is heated by using an induction heating device with a conformal copper pipe coil, the distance between the coil and the blade tip is 5-10mm, and the temperature at the blade tip is 450-550 ℃;
step 6.2, carrying out argon arc welding surfacing for 5-10s after preheating to the temperature, wherein the equipment uses a direct-current fast frequency pulse welding machine, the diameter of a tungsten electrode is 1.2-1.6 mm, the diameter of a nozzle is 8mm, and the welding mode is as follows: a fast frequency secondary pulse mode, wherein the fast frequency current is 20-30A, the frequency f =20000Hz, the main current =30A, the duration time is 0.1s, the auxiliary current is 10A, the duration time is 0.01-0.05 s, and the argon flow is 10-12L/min; the blade tip width is 0.8-2.0 mm, the blade tip defect height is 1-2 mm, and the surfacing height is 3-4 mm; after surfacing, closing the water flow, controlling the temperature of the induction heating device to be reduced by 20 ℃/min, and closing the induction heating device when the temperature is reduced to 100 ℃;
step 7, stress relief annealing: heating to 950-1050 deg.C in vacuum degree better than 10Pa in vacuum heat treatment furnace, maintaining for 1 hr, and cooling with argon to room temperature;
step 8, carrying out nondestructive detection on the blade tip overlaying part and the nearby area, wherein the nondestructive detection comprises visual detection, X-ray detection and fluorescence detection; if the blade tip is unqualified, returning to the step six for repair welding until the blade tip weld-up part is free of defects, and performing repair welding on the same weld-up part for no more than 3 times
Step 9, processing the blade tip profile: fixing and positioning the blade by using a tool, then machining the blade tip of the blade after surfacing by using a numerical control machine according to the digital analogy of the blade, and reserving a margin of 0.2mm on two sides of the blade tip; after machining, polishing and repairing the blade tip by using tools such as files, oilstones and the like, wherein the finally machined blade tip profile is smooth and smooth with the original wing profile;
step 10, restoring the coating: recovering the coating on the surface of the blade, wherein the thickness of the coating is 30-70 mu m;
step 11, final inspection: including visual inspection, dimensional inspection, weighing inspection, flow inspection, fluoroscopy.
2. The method for repairing the blade tip of the gas turbine single crystal superalloy turbine rotor blade according to claim 1, wherein the method comprises the following steps: in step 6, the blade is made of DD5 single crystal, and the welding wire is made of directional solidification high-temperature alloy and comprises the following components: c0.08-0.15, cr6.00-7.50, co 11.00-12.00, W4.50-5.00, mo 1.00-2.00, al 5.00-6.00, ta6.00-6.50, 2.50-3.50, re 2.5-3.5, hf 1.3-1.7, B0.01-0.02, ni 60.00-65.00.
3. The method for repairing the blade tip of the gas turbine single crystal superalloy turbine rotor blade according to claim 2, wherein:
the function of Ta: promote Cr to dissolve into a gamma-phase matrix, cause lattice distortion, improve the strength of a solid solution, improve the oxidation resistance and the high-temperature corrosion resistance of the nickel-based superalloy, and simultaneously resist tensile strength and yield strength;
cr: simultaneously combine with O to form Cr 2 O 3 High temperature and corrosion resistance;
co: the solubility of Cr, mo, W and C in a gamma-phase matrix is increased, the carbide morphology at a crystal boundary is improved, the crystal boundary is strengthened, and meanwhile, the solid solution strengthening is realized, and the hot corrosion resistance is improved;
the function of C: strengthening elements between dendrites and grain boundaries to form discontinuous granular carbide, MC, M 7 C 3 、M 6 C、M 23 C 6 Etc., preventing grain boundary sliding;
the function of Re: the content of the refined structure of the gamma' phase is controlled to be 2.5-3.5%, the durability of the high-temperature alloy is improved, the TCP phase is separated out due to overhigh content, and the durability is seriously reduced;
the function of Ni: the stable elements of the austenite phase form solid solutions with elements such as Cr, co, mo, al, C, B and the like, and the O-affinity promotes the formation of oxide films;
the role of W: obvious lattice expansion is caused, a long-range stress field is formed, dislocation motion is prevented, and therefore yield strength is improved;
the function of Mo: the effect is basically consistent with that of W, solid solution strengthening is performed, the passivation and anti-reduction capability of the alloy is improved, but the content needs to be controlled below 2 percent, and the structure segregation is easily caused when the content is too high;
the function of B: microalloying elements are enriched at the grain boundary, so that the precipitation of harmful phases at the grain boundary is eliminated, and the durability and the creep property are improved;
the function of Al: the gamma' -Ni3Al is generated with Ni, so that the strength is improved, and the oxidation resistance and the corrosion resistance are improved;
the function of Hf: the high-temperature durable plasticity of the high-temperature alloy is improved, the high-temperature notch sensitivity is eliminated, the number of gamma' is increased, and the stability of the MC type carbide is improved.
4. The method for repairing the blade tip of the gas turbine single crystal superalloy turbine rotor blade according to claim 3, wherein: after surfacing, the structures of the blade tips are all small-angle crystal boundaries, wherein the phase difference of adjacent crystal grains is less than 10 degrees, and no mixed crystal exists; the hardness of the surfacing layer is 460HV-475HV, the DD5 matrix is about 440HV, the room temperature performance tensile strength of the joint tensile sample reaches more than 90% of that of the DD5 matrix and is 900-950MPa, and the high temperature endurance performance is more than 85% of that of the DD5 matrix.
5. The method for repairing the blade tip of the gas turbine single crystal superalloy turbine rotor blade according to claim 1, wherein the method comprises the following steps: in a step 6, the process is carried out,
a tenon water-cooling fixing tool is a machining and detecting tool, is formed by printing through a laser selective melting forming technology, is made of GH4169, and then performs mechanical machining on a tenon matching surface of a tenon to ensure that the positioning precision is 0.01mm, and the diameter of an inner runner is phi 6mm.
6. The method for repairing the blade tip of the single crystal superalloy turbine rotor blade of the gas turbine according to claim 1, wherein the method comprises the following steps: in a step 11 of the method, the step of the method,
visual inspection: the surface of the blade is not allowed to be collided or scratched; the surface of the coating is not allowed to have defects of warping, bubbling, cracking and the like, and the tenon area is not coated; visual inspection and probe inspection are carried out on the air film holes on the exhaust edge of the blade piece by piece, and the air film holes are not allowed to be blocked;
and (4) checking the size: measuring the profile degree of the blade tip molded surface of the repaired part by using a detection tool and a three-coordinate measuring instrument, wherein the deviation is +/-0.1 mm, and the repaired part is qualified;
weighing and checking: the weight deviation of the new part is +/-5 g, and the new part is qualified;
and (3) flow inspection: the flow of the main channel is qualified after 6-8L/min;
and (3) fluorescence examination: the fluorescence examination was carried out at HB/Z61, and cracks, pores, inclusions and unfused defects were not allowed.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118061090A (en) * | 2024-04-16 | 2024-05-24 | 成都晨发泰达航空科技股份有限公司 | Thermal barrier coating repairing device and method for APU combustion chamber |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118061090A (en) * | 2024-04-16 | 2024-05-24 | 成都晨发泰达航空科技股份有限公司 | Thermal barrier coating repairing device and method for APU combustion chamber |
| CN118061090B (en) * | 2024-04-16 | 2024-07-09 | 成都晨发泰达航空科技股份有限公司 | Thermal barrier coating repairing device and method for APU combustion chamber |
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