A cored wire for repairing a brake disc of a wind turbine yaw system and a repairing method

Abstract

This invention provides a flux-cored welding wire for repairing yaw system brake discs in wind turbines, comprising a steel sheath and a powdered flux core. By weight percentage, the powdered flux core comprises: 18%–45% ferrosilicon powder, 1.5%–4.6% ferromanganese powder, 15%–40% ferrotitanium powder, 19%–60% nickel powder, 0.02%–0.15% cerium oxide, 0.4%–1.5% tungsten carbide, and the balance being iron powder. Compared with existing technologies, this invention adds tungsten carbide to the flux-cored welding wire, which, in conjunction with the carbides formed during welding, effectively improves the wear resistance of the coating layer. Specifically targeting the actual operating conditions of yaw system brake discs, it achieves excellent wear resistance during braking, extending the service life of the repaired brake disc.

Description

Technical Field

[0001] This invention belongs to the technical field of wind turbine generator sets, and particularly relates to a flux-cored welding wire and repair method for repairing the brake disc of the yaw system of a wind turbine generator set. Background Technology

[0002] As one of the main development directions in the field of new energy power generation technology, wind power generation has seen its installed capacity increase year by year, with single-unit capacity continuously growing. To improve power generation efficiency and fully utilize wind energy resources, large grid-connected wind turbine units are equipped with yaw systems. Through the combined efforts of the wind measurement system, control system, and yaw system, the unit can achieve yaw during wind conditions and emergency yaw in high winds. Currently, wind turbine yaw mainly relies on the electric motor and reduction gearbox installed on the turbine to drive the yaw gear ring. After yawing to the designated position, hydraulic calipers engage to tighten the yaw brake disc, achieving braking and maintaining clamping during turbine operation. Changes in wind direction lead to frequent yaw actions, accelerating the wear of the brake friction pads. If the thinned brake friction pads are not replaced in time, friction between the pads and the brake disc during braking will damage the brake disc. This decrease in braking performance increases the risk of turbine overrun and tower collapse, reducing the safety of turbine operation.

[0003] After yaw brake discs wear out, replacement is the primary solution. However, effective repair methods for damaged brake discs are lacking, leading to a large number of worn brake discs being scrapped. Existing welding repair methods sometimes reduce the wear resistance of the yaw brake discs, and on-tower repair is difficult, making it hard to guarantee repair precision. The yaw brake disc is made of ductile iron, and currently, there are few cladding materials that meet the requirements for automated welding. Furthermore, due to material properties, cracks are prone to occur during welding. Therefore, developing a repair method for yaw brake discs in megawatt-class wind turbines and establishing a process flow is of great significance for ensuring the safe operation of megawatt-class wind turbines and reducing the operation and maintenance costs of wind power equipment. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a flux-cored welding wire for repairing the brake disc of the yaw system of a wind turbine and a repair method thereon.

[0005] This invention provides a flux-cored welding wire for repairing brake discs of wind turbine yaw systems, comprising a steel sheath and a powdered flux core; by mass percentage, the powdered flux core comprises: 18%~45% ferrosilicon powder, 1.5%~4.6% ferromanganese powder, 15%~40% ferrotitanium powder, 19%~60% nickel powder, 0.02%~0.15% cerium oxide, 0.4%~1.5% tungsten carbide, and the balance being iron powder.

[0006] Preferably, the filling rate of the flux-cored welding wire used for repairing the brake disc of the yaw system of the wind turbine is 10~15 wt%.

[0007] This invention also provides a method for repairing the brake disc of a wind turbine yaw system, comprising the following steps:

[0008] S1) The surface of the worn yaw system brake disc of the wind turbine is machined by mechanical cutting;

[0009] S2) Perform non-destructive testing on the yaw system brake disc of the wind turbine after mechanical cutting. If damage is found, repair it by patching or continue mechanical cutting. If no damage is found, proceed to the next step.

[0010] S3) The above-mentioned flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is used to build up the surface of the heated and non-destructive tested yaw system brake disc of the wind turbine.

[0011] S4) Perform mechanical cutting on the weld overlay layer of the yaw system brake disc of the wind turbine after weld overlay;

[0012] S5) Measure the thickness of the brake disc of the yaw system of the wind turbine unit with the weld overlay layer machined by mechanical cutting;

[0013] S6) Perform precision machining on the yaw system brake disc of the wind turbine that meets the size requirements.

[0014] Preferably, in step S1), after removing the surface damage layer by mechanical cutting of the worn yaw system brake disc of the wind turbine, mechanical cutting is continued to cut the upper and lower surfaces of the yaw brake disc of the wind turbine by 3-5 mm thickness, and leveling is performed during the mechanical cutting process.

[0015] Preferably, in step S2), one or more of ultrasonic testing, magnetic particle testing, and penetrant testing are used to perform non-destructive testing on the yaw system brake disc of the wind turbine after mechanical cutting.

[0016] Preferably, in step S2), the damage found after non-destructive testing is a buried defect with a relatively deep depth, which is then repaired by excavation and patching. The damage found is a surface defect with a relatively shallow depth, which is then further processed by mechanical cutting to remove all defects. The excavation and patching is carried out by mechanical processing, and after excavation, nickel-based welding materials are used for dissimilar cold welding repair.

[0017] Preferably, the temperature of the heated and non-destructively tested yaw system brake disc of the wind turbine is 450℃~550℃; the welding is a single-layer multi-pass annular welding, and there is an overlap between adjacent passes.

[0018] Preferably, the welding is performed in a shielding gas; the welding speed is 0.2~0.25 mm / s; the welding current is 160~180 A; the welding arc voltage is 19~24 V; and the overlap portion is 30%~45% of the weld width.

[0019] Preferably, in step S4), after mechanical cutting, non-destructive testing is performed to determine whether there is damage. If there is damage, it is repaired by patching. If there is no damage, steps S3 and S4 are repeated, and the number of repetitions is greater than or equal to 1.

[0020] Preferably, in step S4), the surface is machined to a surface roughness of less than Ra12.5.

[0021] This invention provides a flux-cored welding wire for repairing yaw system brake discs in wind turbines, comprising a steel sheath and a powdered flux core. By weight percentage, the powdered flux core comprises: 18%–45% ferrosilicon powder, 1.5%–4.6% ferromanganese powder, 15%–40% ferrotitanium powder, 19%–60% nickel powder, 0.02%–0.15% cerium oxide, 0.4%–1.5% tungsten carbide, and the balance being iron powder. Compared with existing technologies, this invention adds tungsten carbide to the flux-cored welding wire, which, in conjunction with the carbides formed during welding, effectively improves the wear resistance of the coating layer. Specifically targeting the actual operating conditions of yaw system brake discs, it achieves excellent wear resistance during braking, extending the service life of the repaired brake disc.

[0022] Furthermore, the present invention also provides a method for repairing the yaw system brake disc of a wind turbine, comprising the following steps: S1) machining the surface of the worn yaw system brake disc of the wind turbine; S2) performing non-destructive testing on the machined yaw system brake disc of the wind turbine, and if damage is found, performing patch repair or continuing machining; if no damage is found, proceeding to the next step; S3) applying the flux-cored welding wire for repairing the wind turbine yaw system brake disc to the heated surface of the non-destructive tested wind turbine yaw system brake disc; S4) machining the weld overlay layer of the welded wind turbine yaw system brake disc; S5) measuring the thickness of the weld overlay layer of the wind turbine yaw system brake disc; S6) precision machining the wind turbine yaw system brake disc that meets the dimensional requirements. Compared with existing technologies, the repair method provided by this invention first uses mechanical processing to cut the surface of the yaw brake disc before repair to remove wear marks and performs non-destructive testing to ensure that the surface defects of the brake disc are completely cleaned. Then, during repair, a single-layer, multi-pass process is used for ring-shaped overlay, with a certain overlap between adjacent passes. This ensures that no large welding internal stress is caused during the overlay process, and the overlapping welds also make the overlay repair of the yaw system brake disc more efficient. At the same time, non-destructive testing is used to detect defects during the repair process, and corresponding patching repair schemes are determined for different situations. This allows for better adaptation to patching repair schemes under different conditions, facilitating timely and appropriate handling of defects under different operating conditions, and improving the quality assurance of yaw system brake disc repair. Attached Figure Description

[0023] Figure 1 This is a microstructure diagram of the yaw brake disc coating repaired in Embodiment 1 of the present invention;

[0024] Figure 2 This is a microstructure diagram of the yaw brake disc coating repaired in Embodiment 2 of the present invention;

[0025] Figure 3 This is a microstructure diagram of the yaw brake disc coating repaired in Embodiment 3 of the present invention;

[0026] Figure 4 This is a microstructure diagram of the yaw brake disc coating repaired in Embodiment 4 of the present invention;

[0027] Figure 5 This is a microstructure diagram of the yaw brake disc coating repaired in Embodiment 5 of the present invention;

[0028] Figure 6 This is a microstructure diagram of the yaw brake disc coating repaired in Embodiment 6 of the present invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a flux-cored welding wire for repairing brake discs of wind turbine yaw systems, comprising a steel sheath and a powdered flux core; by mass percentage, the powdered flux core comprises: 18%~45% ferrosilicon powder, 1.5%~4.6% ferromanganese powder, 15%~40% ferrotitanium powder, 19%~60% nickel powder, 0.02%~0.15% cerium oxide, 0.4%~1.5% tungsten carbide, and the balance being iron powder.

[0031] According to the present invention, the steel sheet can be any type of steel sheet known to those skilled in the art, and there are no special restrictions. In the present invention, industrial pure iron is preferred. Compared with low carbon steel strip, steel sheet using industrial pure iron as flux-cored wire has better ductility and can be drawn more easily, reducing the difficulty of wire manufacturing. The width of the steel sheet is preferably 5-10 mm, more preferably 6-8 mm, and even more preferably 7 mm. The thickness of the steel sheet is preferably 0.1-0.5 mm, more preferably 0.2-0.4 mm, and even more preferably 0.3 mm.

[0032] In some embodiments provided by the present invention, the content of the ferrosilicon powder in the powder core is specifically 30%, 45%, 18%, 25% or 35%; the ferrosilicon powder can be any ferrosilicon powder known to those skilled in the art, and there are no special restrictions; in the present invention, the silicon content in the ferrosilicon powder is preferably 65~75 wt%, more preferably 68~72 wt%, and even more preferably 70 wt%.

[0033] In some embodiments provided by the present invention, the content of the manganese iron powder in the powder core is specifically 1.5%, 3% or 4.6%; the manganese iron powder can be any manganese iron powder known to those skilled in the art, and there are no special restrictions. In the present invention, the manganese content in the manganese iron powder is preferably 55~65 wt%, more preferably 58~62 wt%, and even more preferably 60 wt%.

[0034] In some embodiments provided by the present invention, the content of the titanium iron powder in the powder core is specifically 25%, 15%, 40% or 30%; the titanium iron powder can be any titanium iron powder known to those skilled in the art, and there are no special restrictions. In the present invention, the titanium content in the titanium iron powder is preferably 35~45 wt%, more preferably 38~42 wt%, and even more preferably 40 wt%.

[0035] In some embodiments provided by the present invention, the content of nickel powder in the powder core is specifically 25%, 19%, 45% or 60%.

[0036] In some embodiments provided by the present invention, the content of cerium oxide in the powder core is specifically 0.15%, 0.1%, 0.05%, or 0.02%.

[0037] In some embodiments provided by the present invention, the content of tungsten carbide in the powder core is specifically 0.4%, 1.5%, 1%, 0.8%, or 0.6%.

[0038] This invention adds tungsten carbide to the flux-cored welding wire. Tungsten carbide works in conjunction with the carbides formed during the welding process to effectively improve the wear resistance of the coating. It is particularly suitable for the actual use conditions of yaw system brake discs, achieving good wear resistance during braking and extending the service life of the brake disc after repair.

[0039] In this invention, the flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is formed by drawing a powdered flux core wrapped in steel. The filler content of the flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is preferably 10~15 wt%. In some embodiments provided by this invention, the filler content of the flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is specifically 15 wt%, 12 wt%, 10 wt%, or 14 wt%. The filler content range is the average of the test values ​​of the filler content for any two diameters when the diameter of the welding wire is above 2.0 mm during the wire drawing process.

[0040] According to the present invention, the diameter of the flux-cored welding wire used for repairing the brake disc of the yaw system of the wind turbine is preferably 1-2 mm, more preferably 1 mm; it can be stacked with smaller welding process parameters, reducing heat input, effectively reducing welding residual stress during the brake disc stacking process, and avoiding brake disc deformation and cracking of the stacked layer.

[0041] This invention also provides a method for repairing the yaw system brake disc of a wind turbine, comprising the following steps: S1) machining the surface of the worn yaw system brake disc of the wind turbine; S2) performing non-destructive testing on the machined yaw system brake disc; if damage is found, patching or further machining is performed; if no damage is found, proceed to the next step; S3) applying the flux-cored welding wire used for repairing the wind turbine yaw system brake disc to the heated surface of the machined yaw system brake disc after non-destructive testing; S4) machining the weld overlay layer of the machined yaw system brake disc; S5) measuring the thickness of the machined weld overlay layer of the wind turbine yaw system brake disc; S6) precision machining the wind turbine yaw system brake disc that meets the dimensional requirements.

[0042] In this invention, there are no special restrictions on the source of any raw materials; they can be commercially available.

[0043] The surface of the worn yaw system brake disc of the wind turbine is machined by mechanical cutting; the wind turbine yaw system brake disc is preferably a megawatt-class wind turbine yaw system brake disc; the surface damage layer, such as grooves and deformation caused by wear on the brake disc surface, is removed by mechanical cutting; after removing the surface damage layer by mechanical cutting, it is preferable to continue mechanical cutting to cut the upper and lower surfaces of the wind turbine yaw brake disc to a thickness of 3-5 mm, and leveling is performed during the mechanical cutting process.

[0044] Non-destructive testing (NDT) is performed on the yaw system brake disc of the wind turbine after mechanical machining. The NDT method can be any method well-known to those skilled in the art and is not particularly limited. In this invention, one or more of ultrasonic testing, magnetic particle testing, and penetrant testing are preferred for NDT of the mechanically machined wind turbine yaw system brake disc. If damage is found, patching or further mechanical machining is performed. If the damage found after NDT is a buried defect with a deep depth, patching is performed. If the damage is surface damage with a shallow depth, further mechanical machining is performed to remove all defects. The patching is preferably performed by mechanical machining to remove the defect, followed by dissimilar cold welding using a nickel-based welding material. More specifically, the dissimilar cold welding is manual arc welding or manual gas shielded welding. The nickel-based welding material can be any nickel-based welding material well-known to those skilled in the art and is not particularly limited. In this invention, ERNiCrMo type nickel-based welding material is preferred. After patching or further mechanical machining, NDT is preferably performed again to confirm that the defect has been completely removed. If no damage is found, the next step is performed.

[0045] The aforementioned flux-cored welding wire for repairing the yaw system brake disc of a wind turbine is used for welding on the heated surface of the non-destructive testing (NDT) yaw system brake disc of a wind turbine. According to this invention, the NDT yaw system brake disc of the wind turbine is preferably cleaned first, and then heated. Surface cleaning is preferably performed by wiping the surface with alcohol or acetone to remove metal debris and oil. In this invention, the NDT yaw system brake disc of the wind turbine is preferably fixed on a workbench, specifically on a robotic cladding platform, for surface cleaning and heating. The temperature of the heated NDT yaw system brake disc of the wind turbine is preferably 450℃~550℃. When welding one side of the NDT yaw system brake disc, a heating pad is preferably laid on the other side for insulation. The flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is used for welding on the heated surface of the NDT yaw system brake disc of the wind turbine. The flux-cored welding wire used for repairing the yaw system brake disc of the motor unit is as described above and will not be repeated here. The welding is preferably a single-layer, multi-pass annular welding, with overlapping portions between adjacent passes. Using a single-layer, multi-pass annular welding avoids the problem of excessive residual stress and workpiece deformation caused by the large size of the yaw brake disc and excessive welding heat input. In this invention, it is further preferred that the single-layer, multi-pass annular welding is performed from the inner ring to the outer ring. The welding is preferably carried out in a protective gas. The protective gas can be any gas known to those skilled in the art and is not particularly limited. In this invention, the protective gas preferably includes an inert gas and carbon dioxide. The volume content of carbon dioxide in the protective gas is preferably 3%~10%, more preferably 5%~8%, and even more preferably 8%. The inert gas can be any inert gas known to those skilled in the art and is not particularly limited. In this invention, argon is preferred. The welding speed is preferably 0.2~0.25. The welding speed is 0.25 mm / s, 0.23 mm / s, 0.2 mm / s, 0.22 mm / s, or 0.24 mm / s in some embodiments of the present invention. The welding current is preferably 160-180 A. In some embodiments of the present invention, the welding current is preferably 180 A, 170 A, 160 A, 172 A, or 165 A. The welding arc voltage is preferably 19-24 V. In some embodiments of the present invention, the welding arc voltage is preferably 19 V, 22 V, 24 V, or 23 V. The overlapping portion is preferably 30%-45% of the weld width. In some embodiments of the present invention, the overlapping portion is specifically 45%, 40%, 30%, or 35% of the weld width. In the present invention, the welding is preferably performed by a welding system. The welding system preferably consists of an automatic welding platform (welding robot) and a rotary welding platform.

[0046] The weld overlay layer of the yaw system brake disc of the wind turbine is mechanically machined; the mechanical machining ensures that the grooves between each weld bead are completely removed; in this invention, the mechanical machining is preferably performed until the surface roughness is less than Ra12.5; after the mechanical machining, non-destructive testing is preferably performed to determine whether there is damage. If there is damage, it is repaired by patching; if there is no damage, steps S3) and S4) are repeated more than or equal to 1 time; the non-destructive testing method can be any method known to those skilled in the art and there are no special limitations. In this invention, one or more of ultrasonic testing, magnetic particle testing and penetrant testing are preferably used; the non-destructive testing determines whether there is surface and internal damage; the patching repair in this step preferably uses the weld overlay process in step S3); after patching repair, non-destructive testing is preferably repeated; by repeating steps S3) and S4), multiple layers of weld overlay can be formed on the surface of the yaw brake disc. The number of weld overlay layers can be selected according to the degree of wear. If the wear is severe, the number of weld overlay layers can be increased as needed, but it is preferred that the number of weld overlay layers on each surface is greater than or equal to 2 layers.

[0047] Then, the thickness of the wind turbine yaw system brake disc with the mechanically machined weld overlay is measured. The measurement is used to determine whether the mechanically machined weld overlay meets the yaw brake disc size requirements. If it meets the requirements, the next process is carried out. If the thickness does not meet the requirements, steps S3 and S4 are repeated as needed.

[0048] Finally, the yaw system brake disc of the wind turbine that meets the size requirements is precision machined so that the surface roughness and runout of the brake disc meet the requirements. The precision machining method can be any method known to those skilled in the art and there are no special restrictions. In this invention, the precision machining allowance is preferably less than 1 mm.

[0049] It should be noted that the repair methods used for the two surfaces, i.e. the two working surfaces, of the yaw system brake disc of the wind turbine should be consistent when repairing them. Therefore, this will not be elaborated on here in the specification of this invention.

[0050] In a specific embodiment of the present invention, the method for repairing the brake disc of the yaw system of the wind turbine specifically includes:

[0051] Step 1: Prepare a flux-cored welding wire with a filling amount of 10 wt.%~15 wt.%. The mass percentages of various powders in the flux core are as follows: ferrosilicon powder 18.0%~45.0%, ferromanganese powder 1.50%~4.60%, ferrotitanium powder 15.0%~40.0%, nickel powder 19.0%~60.0%, cerium oxide 0.02%~0.15%, tungsten carbide 0.40%~1.50%, and iron powder as the balance. The sum of the mass percentages of all powders is 100%.

[0052] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a thickness of 3-5 mm from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0053] Step 3: Perform non-destructive testing (NDT) on the machined yaw brake disc using ultrasonic and penetrant methods. If no damage is detected, proceed to the next step. If damage is found, repair it by excavation or increase the machining thickness based on the test results. If the damaged area is located and found to be a buried defect with a deep depth, excavate it using machining, and then repair it by dissimilar cold welding with nickel-based welding wire. If it is a surface defect with a shallow depth, increase the machining thickness to completely remove the defect, and then perform NDT again using ultrasonic and penetrant testing to confirm that the defect has been completely removed.

[0054] Step 4: Fix the machined and non-destructive testing-compliant brake disc onto the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0055] Step 5: Heat the fixed yaw brake disc to 450~550℃ and hold it at that temperature. Use the prepared flux-cored welding wire to build up the surface of the brake disc. The process parameters during the building up process are: welding current 160~180 A, arc voltage 19~24V, building up speed 0.2~0.25 mm / s, single-layer multi-pass ring building up, with a certain overlap between adjacent passes, the width of which is 30%~45% of the width of the building up weld.

[0056] Step 6: After the single-layer weld overlay is completed, the weld overlay layer is machined to ensure that the grooves between the weld passes are completely removed and the surface roughness is less than Ra12.5. After machining, the brake disc is subjected to non-destructive testing. No cracks, porosity, or other defects are found on the brake disc after the weld overlay. The above process is repeated for the second layer overlay, and machining is performed to meet the aforementioned requirements.

[0057] Step 7: Measure the thickness of the yaw brake disc after completing Step 6 to determine if it meets the yaw brake disc size requirements. If it does, proceed to the next process step; otherwise, repeat the process flow in Step 6.

[0058] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0059] The repair method provided by this invention first uses mechanical processing to cut the surface of the yaw brake disc before repair to remove wear marks and performs non-destructive testing to ensure that surface defects of the brake disc are completely removed. Then, during repair, a single-layer, multi-pass process is used for ring-shaped overlay, with a certain overlap between adjacent passes. This ensures that no large welding internal stress is caused during the overlay process, and the overlapping welds also make the overlay repair of the yaw system brake disc more efficient. At the same time, non-destructive testing is used to detect defects during the repair process, and corresponding patching repair schemes are determined for different situations. This allows for better adaptation to patching repair schemes under different conditions, facilitating timely and appropriate handling of defects under different operating conditions, and improving the quality assurance of yaw system brake disc repair.

[0060] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a flux-cored welding wire for repairing the brake disc of a wind turbine yaw system and a repair method thereof.

[0061] All reagents used in the following examples are commercially available; the diameter of the flux-cored wire used in the examples is 1 mm; the specifications of the ferrosilicon powder used in the examples are: Si content 70 wt.%, ferromanganese powder: Mn content 60 wt.%, and ferrotitanium powder: Ti content 40 wt.%.

[0062] Example 1

[0063] Step 1: The mass percentages of each powder in the flux-cored wire powder are as follows: ferrosilicon powder 30.0%, ferromanganese powder 1.50%, ferrotitanium powder 25.0%, nickel powder 25.0%, cerium oxide 0.15%, tungsten carbide 0.40%, and iron powder 17.95%. The flux-cored wire filling rate is 15 wt.%.

[0064] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a 4 mm thickness from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0065] Step 3: The machined yaw brake disc was subjected to non-destructive testing using ultrasonic and penetrant methods. No damage or defects were found in the machined yaw brake disc.

[0066] Step 4: Fix the brake disc on the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0067] Step 5: Heat the fixed yaw brake disc to 450℃ and hold it at that temperature. Use the prepared flux-cored welding wire to deposit on the surface of the brake disc. The process parameters during the depositing process are: welding current 180 A, arc voltage 19 V, depositing speed 0.25 mm / s, single-layer multi-pass annular depositing, with a certain overlap between adjacent passes, the width of which is 45% of the width of the cladding weld.

[0068] Step 6: After each layer is deposited, the deposited layer is machined to ensure that the grooves between the weld passes are completely removed and the surface roughness is less than Ra12.5. After machining, the deposited brake disc is subjected to non-destructive testing. After the deposit is completed, the brake disc does not have defects such as cracks or pores. In this embodiment, two layers are deposited on each of the two working surfaces with the same parameters.

[0069] Step 7: Measure the thickness of the yaw brake disc after completing step 6 to ensure it meets the yaw brake disc size requirements.

[0070] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0071] The yaw brake disc repaired using the process and parameters described in Example 1 exhibits good surface forming quality, with good metallurgical bonding between the overlay layer and the original yaw brake disc substrate. Its microstructure is shown in [the diagram]. Figure 1 As shown. The repaired yaw brake disc performs well, with a hardness test result of 48HRC. This process is suitable for repairing yaw brake discs in wind turbines.

[0072] Example 2

[0073] Step 1: The mass percentages of each powder in the core powder are as follows: ferrosilicon powder 45.0%, ferromanganese powder 3.0%, ferrotitanium powder 15.0%, nickel powder 19.0%, cerium oxide 0.10%, tungsten carbide 1.50%, and iron powder 16.40%. The core filling rate is 12 wt.%.

[0074] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a 5mm thickness from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0075] Step 3: The machined yaw brake disc underwent non-destructive testing using ultrasonic and penetrant methods. The ultrasonic testing results indicated a defect with a certain depth. The deep area was marked, and the defect was removed mechanically. After cleaning the surrounding area, manual gas shielded welding was used to repair the defect with ERNiCrMo type nickel-based welding material. After completion, machining and non-destructive testing were performed again, and the defect disappeared.

[0076] Step 4: Fix the machined and non-destructive tested brake disc onto the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0077] Step 5: Heat the fixed yaw brake disc to 550℃ and hold it at that temperature. Use the prepared flux-cored welding wire to deposit on the surface of the brake disc. The process parameters during the depositing process are: welding current 170 A, arc voltage 22 V, depositing speed 0.23 mm / s, single-layer multi-pass annular depositing, with a certain overlap between adjacent passes, the width of which is 40% of the width of the cladding weld.

[0078] Step 6: After the single-layer deposition is completed, the deposition layer is machined to ensure that the grooves between the weld passes are completely removed and the surface roughness is less than Ra12.5. After machining, the deposited brake disc is subjected to non-destructive testing. The brake disc was found to be free of cracks, porosity, or other defects after deposition. In this embodiment 2, two layers of the same parameters were used to deposit on each of the two working surfaces.

[0079] Step 7: Measure the thickness of the yaw brake disc after completing step 6 to ensure it meets the yaw brake disc size requirements.

[0080] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0081] The yaw brake disc repaired using the process and parameters described in Example 2 showed good surface forming quality, with good metallurgical bonding between the overlay layer and the original yaw brake disc substrate. Its microstructure is shown in [the image / description]. Figure 2 As shown. The repaired yaw brake disc performs well, with a hardness test result of 50HRC. This process is suitable for repairing yaw brake discs in wind turbines.

[0082] Example 3

[0083] Step 1: The mass percentages of each powder in the prepared core powder are as follows: ferrosilicon powder 18.0%, ferromanganese powder 4.60%, ferrotitanium powder 40.0%, nickel powder 19.0%, cerium oxide 0.05%, tungsten carbide 1.0%, and iron powder 17.35%. The filling rate is 10 wt.%.

[0084] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a 3 mm thickness from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0085] Step 3: The machined yaw brake disc was subjected to non-destructive testing using ultrasonic and penetrant methods. According to the test results, there was a surface defect on one side of the working surface of the brake disc with a shallow depth. The machining thickness was increased, and the defect was finally removed when the cutting thickness was 6 mm. In this embodiment, the same parameters were used to stack a total of 3 layers.

[0086] Step 4: Fix the machined and non-destructive tested brake disc onto the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0087] Step 5: Heat the fixed yaw brake disc to 500℃ and hold it at that temperature. Use the prepared flux-cored welding wire to deposit on the surface of the brake disc. The process parameters during the depositing process are: welding current 160 A, arc voltage 24 V, depositing speed 0.2 mm / s, single-layer multi-pass annular depositing, with a certain overlap between adjacent passes, the width of which is 30% of the width of the cladding weld.

[0088] Step 6: After the single-layer deposition is completed, the deposition layer is machined to ensure that the grooves between the weld passes on the surface are completely removed and the surface roughness is less than Ra12.5. After machining, the brake disc after deposition is subjected to non-destructive testing. After deposition, the brake disc has no defects such as cracks or pores. In this embodiment 3, one working surface is deposited with 3 layers with the same parameters, and the other working surface is deposited with 2 layers.

[0089] Step 7: Measure the thickness of the yaw brake disc after completing step 6 to ensure it meets the yaw brake disc size requirements.

[0090] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0091] The surface forming quality of the yaw brake disc repaired using the process and parameters described in Example 3 is generally good, with good metallurgical bonding between the overlay layer and the original yaw brake disc substrate. Its microstructure is shown in [the diagram]. Figure 3 As shown in the image, the repaired yaw brake disc performs well, with a hardness test result of 54 HRC. This process is suitable for repairing yaw brake discs in wind turbines.

[0092] Example 4

[0093] Step 1: The mass percentages of the powders in the core powder preparation are as follows: ferrosilicon powder 25.0%, ferromanganese powder 4.60%, ferrotitanium powder 15.0%, nickel powder 45.0%, cerium oxide 0.02%, tungsten carbide 0.80%, and iron powder 9.58%. The filling rate is 10 wt.%.

[0094] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a 3.5 mm thickness from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0095] Step 3: The machined yaw brake disc was subjected to non-destructive testing using ultrasonic and penetrant methods. No damage or defects were found in the machined yaw brake disc.

[0096] Step 4: Fix the machined and non-destructive tested brake disc onto the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0097] Step 5: Heat the fixed yaw brake disc to 550℃ and hold it at that temperature. Use the prepared flux-cored welding wire to deposit it on the surface of the brake disc. The process parameters during the depositing process are: welding current 172 A, arc voltage 23 V, depositing speed 0.22 mm / s, single-layer multi-pass annular depositing, with a certain overlap between adjacent passes, the width of which is 35% of the width of the cladding weld.

[0098] Step 6: After the single-layer deposition is completed, the deposition layer is machined to ensure that the grooves between the weld passes on the surface are completely removed and the surface roughness is less than Ra12.5. After machining, the brake disc after deposition is subjected to non-destructive testing. After deposition, the brake disc does not have defects such as cracks or pores. In this embodiment 4, two layers are deposited on each of the two working surfaces with the same parameters.

[0099] Step 7: Measure the thickness of the yaw brake disc after completing step 6 to ensure it meets the yaw brake disc size requirements.

[0100] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0101] The yaw brake disc repaired using the process and parameters described in Example 4 exhibits good surface forming quality, with good metallurgical bonding between the overlay layer and the original yaw brake disc substrate. Its microstructure is shown in [the diagram]. Figure 4 As shown. The repaired yaw brake disc performs well, with a hardness test result of 51HRC. This process is suitable for repairing yaw brake discs in wind turbines.

[0102] Example 5

[0103] Step 1: The mass percentages of each powder in the core powder are as follows: ferrosilicon powder 18.0%, ferromanganese powder 1.50%, ferrotitanium powder 15.0%, nickel powder 60.0%, cerium oxide 0.15%, tungsten carbide 1.50%, and iron powder 3.85%. The filling rate is 14 wt.%.

[0104] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a 5mm thickness from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0105] Step 3: The machined yaw brake disc was subjected to non-destructive testing using ultrasonic and penetrant methods. No damage or defects were found in the machined yaw brake disc.

[0106] Step 4: Fix the machined and non-destructive tested brake disc onto the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0107] Step 5: Heat the fixed yaw brake disc to 450℃ and hold it at that temperature. Use the prepared flux-cored welding wire to deposit on the surface of the brake disc. The process parameters during the depositing process are: welding current 160 A, arc voltage 19 V, depositing speed 0.24 mm / s, single-layer multi-pass annular depositing, with a certain overlap between adjacent passes, the width of which is 30% of the width of the cladding weld.

[0108] Step 6: After the single-layer deposition is completed, the deposition layer is machined to ensure that the grooves between the weld passes on the surface are completely removed and the surface roughness is less than Ra12.5. After machining, the brake disc after deposition is subjected to non-destructive testing. After deposition, the brake disc has no defects such as cracks or pores. In this embodiment 5, the working surfaces on both sides are deposited with 3 layers each with the same parameters.

[0109] Step 7: Measure the thickness of the yaw brake disc after completing step 6 to ensure it meets the yaw brake disc size requirements.

[0110] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0111] The yaw brake disc repaired using the process and parameters described in Example 5 exhibits good surface forming quality, with good metallurgical bonding between the overlay layer and the original yaw brake disc substrate. Its microstructure is shown in [the image / description]. Figure 5 As shown. The repaired yaw brake disc performs well, with a hardness test result of 52HRC. This process is suitable for repairing yaw brake discs in wind turbines.

[0112] Example 6

[0113] Step 1: The mass percentages of each powder in the core powder are as follows: ferrosilicon powder 35.0%, ferromanganese powder 3.0%, ferrotitanium powder 30.0%, nickel powder 25.0%, cerium oxide 0.10%, tungsten carbide 0.60%, and iron powder 6.30%. The filling rate is 10 wt.%.

[0114] Step 2: Machining the upper and lower surfaces of the worn yaw brake disc removes surface damage layers caused by wear, such as grooves and deformation. After removing the damaged surface layers, machining is performed again to cut a 3mm thickness from each of the upper and lower surfaces of the yaw brake disc, and leveling is done during the machining process.

[0115] Step 3: The machined yaw brake disc was subjected to non-destructive testing using ultrasonic and penetrant methods. No damage or defects were found in the machined yaw brake disc.

[0116] Step 4: Fix the machined and non-destructive tested brake disc onto the robot cladding platform, clean the surface of the brake disc, and wipe the upper and lower surfaces of the brake disc with a cotton cloth soaked in alcohol or acetone to remove metal debris and oil stains.

[0117] Step 5: Heat the fixed yaw brake disc to 520℃ and hold it at that temperature. Use the prepared flux-cored welding wire to deposit on the surface of the brake disc. The process parameters during the depositing process are: welding current 165 A, arc voltage 24 V, depositing speed 0.20 mm / s, single-layer multi-pass annular depositing, with a certain overlap between adjacent passes, the width of which is 35% of the width of the cladding weld.

[0118] Step 6: After the single-layer deposition is completed, the deposition layer is machined to ensure that the grooves between the weld passes on the surface are completely removed and the surface roughness is less than Ra12.5. After machining, the brake disc after deposition is subjected to non-destructive testing. After deposition, the brake disc has no defects such as cracks or pores. In this embodiment 6, two layers are deposited on each of the two working surfaces with the same parameters.

[0119] Step 7: Measure the thickness of the yaw brake disc after completing step 6 to ensure it meets the yaw brake disc size requirements.

[0120] Step 8: Perform precision machining on the yaw brake disc to ensure that the surface roughness and runout of the brake disc meet the required range.

[0121] The yaw brake disc repaired using the process and parameters described in Example 6 exhibits good surface forming quality, with good metallurgical bonding between the overlay layer and the original yaw brake disc substrate. Its microstructure is shown in [the diagram]. Figure 6 As shown. The repaired yaw brake disc performs well, with a hardness test result of 45HRC. This process is suitable for repairing yaw brake discs in wind turbines.

[0122] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of repairing a brake disc for a wind turbine yaw system, characterized in that, Includes the following steps: S1) The surface of the worn yaw system brake disc of the wind turbine is machined by mechanical cutting; S2) Perform non-destructive testing on the yaw system brake disc of the wind turbine after mechanical cutting. If damage is found, repair it by patching or continue mechanical cutting. If no damage is found, proceed to the next step. S3) The flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is used to build up the surface of the heated and non-destructive tested yaw system brake disc of the wind turbine. The flux-cored welding wire for repairing the brake disc of the yaw system of the wind turbine includes a steel sheet and a powdered flux core. By weight percentage, the powdered core comprises: 18%~45% ferrosilicon powder, 1.5%~4.6% ferromanganese powder, 15%~40% ferrotitanium powder, 19%~60% nickel powder, 0.02%~0.15% cerium oxide, 0.4%~1.5% tungsten carbide, and the balance being iron powder; the filling rate of the flux-cored welding wire for repairing the yaw system brake disc of the wind turbine is 10~15 wt%. S4) Perform mechanical cutting on the weld overlay layer of the yaw system brake disc of the wind turbine after weld overlay; S5) Measure the thickness of the yaw system brake disc of the wind turbine with the weld overlay layer machined by mechanical cutting; S6) Perform precision machining on the yaw system brake disc of the wind turbine that meets the size requirements; The weld overlay is a single-layer, multi-pass annular weld overlay, with an overlapping portion between adjacent passes; the overlapping portion is 30% to 45% of the weld width.

2. The repair method according to claim 1, characterized in that, In step S1), after removing the surface damage layer by mechanical cutting, the upper and lower surfaces of the wind turbine yaw system brake disc are cut to a thickness of 3-5 mm, and leveling is performed during the mechanical cutting process.

3. The repair method of claim 1, wherein In step S2), one or more of ultrasonic testing, magnetic particle testing, and penetrant testing are used to perform non-destructive testing on the yaw system brake disc of the wind turbine after mechanical cutting.

4. The repair method of claim 1, wherein In step S2), if the damage found after non-destructive testing is a buried defect and the defect depth is relatively deep, it is repaired by excavation. If the damage is a surface defect and the depth is relatively small, mechanical cutting is continued to remove all defects. The excavation and repair is carried out by mechanical processing. After excavation, nickel-based welding material is used for dissimilar cold welding repair.

5. The method of repairing according to claim 1, wherein, The temperature of the heated and non-destructively tested yaw system brake disc of the wind turbine is 450℃~550℃.

6. The repair method of claim 5, wherein The welding is performed in a protective gas atmosphere; the welding speed is 0.2~0.25 mm / s; the welding current is 160~180 A; and the welding arc voltage is 19~24 V.

7. The repair method according to claim 1, characterized in that, In step S4), after mechanical cutting, non-destructive testing is performed to determine whether there is damage. If there is damage, it is repaired by patching. If there is no damage, steps S3 and S4 are repeated, and the number of repetitions is greater than or equal to 1.

8. The repair method according to claim 1, characterized in that, In step S4), the surface is machined to a roughness less than Ra12.5.

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