Method for repairing variable pitch and yaw gears of wind power generation

Abstract

The invention relates to the technical field of gear repair methods, and discloses a wind power generation variable pitch and yaw gear repair method which comprises the following steps: S1, flaw detection and cleaning: performing PT flaw detection on a to-be-repaired gear, and then cutting, polishing and removing all crack sources on the gear; s2, preheating: uniformly heating the periphery of a welding area to 100 DEG C through a heater, and then preserving heat by using a heat preservation blanket and slowly cooling to 80 DEG C; s3, forming of a base coat: arranging welding beads along the length direction of the original tooth by adopting multi-layer and multi-pass cladding welding through a welding machine, and forming the base coat with a trapezoidal cross section through surfacing welding; s4, cladding of a wear-resistant layer: carrying out multi-layer and multi-pass cladding welding on 42CrMo4V special steel to form the wear-resistant layer covering the outer part of the base layer; according to the repairing method for the wind power generation variable pitch and yaw gear, the problem that in the prior art, it is difficult to conduct high-quality re-repairing on the gear of a wind power generator is solved.

Description

Technical Field

[0001] The invention relates to the technical field of gear repair methods, and in particular to a repair method for wind power generation variable pitch and yaw gears. Background Art

[0002] The wind turbine's pitch and yaw gears are key components of the generator. Since the wind turbine's pitch and yaw gears have their service life, a large number of gears with tooth surface defects are generated every year. The wind turbine is more than 100 meters high, and when the gears are broken, they need to be dropped and replaced, which results in a large amount of consumables expenditure. Therefore, how to perform high-quality repair of the wind turbine's gears has become an urgent problem that needs to be solved. Summary of the invention

[0003] The object of the present invention is to provide a method for repairing wind turbine pitch and yaw gears to solve at least one of the above problems existing in the prior art.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for repairing a wind turbine pitch and yaw gear comprises the following steps:

[0006] S1. Flaw detection and cleaning: Perform PT flaw detection on the gear to be repaired, then cut, grind and remove all crack sources on the gear, clean it with a cleaning agent, and then perform PT flaw detection again. After passing the test, start welding repair work;

[0007] S2. Preheating: Heat the area around the welding area uniformly to 100°C through the heater, and then slowly cool it down to 80°C with a thermal blanket;

[0008] S3, base layer forming: multi-layer and multi-pass cladding welding is adopted by the welding machine, and the welds are arranged along the length direction of the original tooth to form a base layer with a trapezoidal cross section, and then the base layer is lightly polished, PT flaw detection and cleaning are carried out in sequence;

[0009] S4. Wear-resistant layer cladding: 42CrMo4V special steel is used for multi-layer and multi-pass cladding welding. The welds are arranged along the length direction of the original tooth to form a wear-resistant layer covering the outside of the base layer. The thickness of the wear-resistant layer is controlled between 1mm and 2.5mm.

[0010] This technical solution uses a heater to evenly heat the area around the welding area to 100°C, and then uses an insulation blanket to slowly cool it down to 80°C. The purpose is to ensure the preheating effect while avoiding the occurrence of gear cracks caused by rapid cooling. During the base layer forming process, a welding machine is used to perform multi-layer and multi-pass cladding welding, and weld beads are arranged along the length of the original tooth to form a base layer with a trapezoidal cross section. The size of this base layer is slightly smaller than the size of the original tooth, which is convenient for forming a wear-resistant layer on the surface of the base layer to form a repair tooth with the same size as the original tooth. The wear-resistant layer is clad welded with 42CrMo4V special steel. After cladding welding with 42CrMo4V special steel, the hardness of the wear-resistant layer can reach the same hardness standard as the original tooth, meeting the repair requirements for the original tooth.

[0011] Furthermore, in order to perform uniform preheating within a suitable range, in S2, the heated width is not less than 100 mm.

[0012] Furthermore, in order to reserve the thickness of the wear-resistant layer, in S3, the base coating is finished when the size of the base coating is uniformly smaller than the original tooth by 1.5 mm±0.5 mm.

[0013] Furthermore, in S3, during the process of welding and forming the base layer, after each layer is welded, tap it lightly with a small hammer until the temperature of the layer is less than or equal to 80°C, and then stop tapping to remove internal stress.

[0014] Furthermore, in S3, during the base layer welding process, after each welding pass is completed, the temperature is lowered to 100°C-200°C before the next welding pass is carried out. During the welding process, a small hammer is used to tap the edge of the weld to release the welding residual stress.

[0015] Furthermore, in order to reserve the size for subsequent grinding, in S4, when the cladding thickness of the wear-resistant layer is greater than the target value of 0.5 mm-1 mm, the cladding of the wear-resistant layer is stopped, and then a thermal insulation blanket is used to keep the temperature and slowly cool for more than 30 minutes.

[0016] Furthermore, since there will be inaccuracies in the inspection on the same day after the base layer welding is completed, in order to achieve a more accurate inspection effect, in S3, it is necessary to perform PT inspection on the second day after the base layer forming is completed to ensure that there are no cracks and visually check the welding effect. If there are defects, use an angle grinder to grind and remove the defects, and then repair them.

[0017] Furthermore, in S3, if the volume of the original tooth is large, during the base layer welding process, a homogeneous body consistent with the original tooth material is added inside the base layer.

[0018] If the volume of the original tooth is large, the volume of the cladding weld is also large, which is prone to cracking. Therefore, adding a homogeneous body consistent with the original tooth material inside the base layer and using a homogeneous sandwich cladding method can reduce the volume of the cladding weld and make it less likely to crack.

[0019] Furthermore, in order to form a repaired tooth having the same appearance as the original tooth, in S4, the wear-resistant layer is polished, PT-detected and cleaned after being clad.

[0020] Furthermore, in order to detect the temperature value more accurately, in S2, a temperature gun is used to perform multi-point temperature measurement in the welding area.

[0021] The beneficial effects of the present invention are as follows: the technical solution, because the surrounding of the welding area is uniformly heated to 100°C by a heater, and then the temperature is slowly lowered to 80°C by an insulation blanket, the purpose is to ensure the preheating effect while avoiding the generation of gear cracks caused by rapid cooling. During the formation of the base layer, multi-layer and multi-pass cladding welding is performed by a welding machine, and weld beads are arranged along the length direction of the original tooth to form a base layer with a trapezoidal cross section. The size of this base layer is slightly smaller than the size of the original tooth, which is convenient for forming a wear-resistant layer on the surface of the base layer to form a repair tooth with the same size as the original tooth. The wear-resistant layer is clad welded with 42CrMo4V special steel. After cladding welding with 42CrMo4V special steel, the hardness of the wear-resistant layer can reach the hardness standard consistent with the original tooth, meeting the repair requirements for the original tooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A physical picture showing the main visual status of the restoration process;

[0023] Figure 2 This is a side view of the restoration process.

[0024] Figure 3 This is a real picture of the original tooth after it was artificially damaged during the restoration test;

[0025] Figure 4 This is a physical picture of the repair process in the repair test;

[0026] Figure 5 This is the actual picture after welding in the repair test;

[0027] Figure 6 This is the actual picture after polishing in the restoration test;

[0028] Figure 7 This is a physical picture of the flaw detection steps after grinding in the repair test. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0030] Embodiment 1:

[0031] like Figure 1-Figure 7 As shown, this embodiment provides a method for repairing a wind turbine pitch and yaw gear, comprising the following steps:

[0032] S1. Flaw detection and cleaning: Perform PT flaw detection on the gear to be repaired, then cut, grind and remove all crack sources on the gear, clean it with a cleaning agent, and then perform PT flaw detection again. After passing the test, start welding repair work;

[0033] S2. Preheating: Heat the area around the welding area evenly to 100°C through a heater. You can use a handheld heating spray gun to evenly heat the area around the welding area, and then use a thermal blanket to slowly cool it down to 80°C.

[0034] S3, base layer forming: multi-layer and multi-pass cladding welding is adopted by a welding machine, and weld beads are arranged along the length direction of the original tooth to form a base layer with a trapezoidal cross section. Preferably, the material of the base layer is consistent with the material of the original tooth. Then, the base layer is lightly polished, PT tested and cleaned in turn;

[0035] In this step, it should be noted that when welding, the gas is connected to the welding system (using high-purity argon), and then the welding machine is debugged, the welding current is adjusted to an appropriate value, and the base layer forming welding is started.

[0036] S4. Wear-resistant layer cladding: Use 42CrMo4V special steel for multi-layer and multi-pass cladding welding, arrange the welds along the length direction of the original tooth to form a wear-resistant layer covering the outside of the base layer, the thickness of the wear-resistant layer is controlled between 1mm-2.5mm, preferably, the thickness is controlled at 2mm±0.5mm, the size detection in this step can be measured by caliper or calliper, combined with the size of other original teeth on the gear, comparative measurement can be performed.

[0037] This technical solution uses a heater to evenly heat the area around the welding area to 100°C, and then uses an insulation blanket to slowly cool it down to 80°C. The purpose is to ensure the preheating effect while avoiding the occurrence of gear cracks caused by rapid cooling. During the base layer forming process, a welding machine is used to perform multi-layer and multi-pass cladding welding, and weld beads are arranged along the length of the original tooth to form a base layer with a trapezoidal cross section. The size of this base layer is slightly smaller than the size of the original tooth, which is convenient for forming a wear-resistant layer on the surface of the base layer to form a repair tooth with the same size as the original tooth. The wear-resistant layer is clad welded with 42CrMo4V special steel. After cladding welding with 42CrMo4V special steel, the hardness of the wear-resistant layer can reach the same hardness standard as the original tooth, meeting the repair requirements for the original tooth.

[0038] The material description of 42CrMo special steel is as follows:

[0039] 42CrMo special steel is an ultra-high strength steel. As the material of the gear body, its tensile strength is

[0040] Rm = 1050-1100MPa has no obvious temper brittleness, has a higher fatigue limit and impact resistance after quenching and tempering, and has good low-temperature impact toughness. The chemical composition of 42CrMo special steel is shown in Table 1:

[0041] Table 1

[0042] Element C Si Mn S P Cr Mo other content% 0.38-0.45 0.17-0.37 0.50-0.80 ≤0.035 ≤0.035 0.9-1.2 0.15-0.25 bal

[0043] The carbon equivalent formula for hardening tendency of low alloy structural steel recommended by the International Institute of Welding (IIW) calculates that the carbon equivalent of 42CrMo steel is ceq=0.9. It has problems such as sensitivity to cold cracks, high hardening tendency, embrittlement in the overheated zone, and softening in the heat-affected zone. Therefore, it is necessary to adopt a reasonable welding process, use welding rods with good toughness, and use welding methods and processes with low heat input.

[0044] According to the requirements of the on-site repair conditions, the repair material needs to have sufficient toughness and match the performance of the substrate. Therefore, Material 1 and Material 2 are selected as the welding materials for the base layer and the wear-resistant layer respectively. The characteristics of the gear body material, Material 1 (base layer material) and Material 2 (wear-resistant layer material / 42CrMo4V special steel) are shown in Table 2:

[0045] Table 2: Material properties

[0046]

[0047] Table 3: Measured values ​​of performance of Material 1 (base material)

[0048]

[0049] Table 4: Hardness test results after surfacing using Material 2 (wear-resistant layer material / 42CrMo4V special steel)

[0050]

[0051] According to the experimental test results, the base material has high strength and excellent plasticity and toughness, with a tensile strength of over 960MPa. The surface wear-resistant layer material has good hardness, HRC57.7-60.5, which is equivalent to the hardness of the gear induction quenching layer.

[0052] Table 5: Test data of the gear after repair according to this method

[0053]

[0054]

[0055] Embodiment 2:

[0056] This embodiment is optimized based on the above-mentioned embodiment 1.

[0057] In order to perform uniform preheating within a suitable range, in S2, the heating width is not less than 100 mm, that is, the circumferential distance from the gear to the position to be welded.

[0058] Embodiment 3:

[0059] This embodiment is optimized based on the above-mentioned embodiment 1.

[0060] In order to reserve the thickness of the wear-resistant layer, in S3, the base layer is finished when the size of the base layer is uniformly smaller than the original tooth by 1.5 mm ± 0.5 mm. The size detection in this step can be measured by a caliper or a calliper, and a comparative measurement can be performed in combination with the size of other original teeth on the gear.

[0061] Embodiment 4:

[0062] This embodiment is optimized based on the above-mentioned embodiment 1.

[0063] In S3, during the process of base layer welding, after each layer is welded, tap it gently with a small hammer until the temperature of the layer is less than or equal to 80°C, then stop tapping to remove internal stress. The tapping time is generally about 2 minutes.

[0064] Embodiment 5:

[0065] This embodiment is optimized based on the above-mentioned embodiment 1.

[0066] In S3, during the base layer welding process, after each welding pass is completed, the temperature is lowered to 100℃-200℃ before the next welding pass is carried out. During the welding process, a small hammer is used to tap the edge of the weld to release the welding residual stress.

[0067] Embodiment 6:

[0068] This embodiment is optimized based on the above-mentioned embodiment 1.

[0069] In order to reserve the size for subsequent grinding, in S4, when the cladding thickness of the wear-resistant layer is greater than the target value of 0.5mm-1mm, the wear-resistant layer cladding is stopped, and then the heat insulation blanket is used to keep warm and slowly cool for more than 30 minutes. If the ambient temperature is too low, it is less than or equal to 0 degrees and it is further slowly cooled for 30 minutes (it can be covered with heat insulation cotton for heat insulation). The size detection in this step can be measured by calipers or callipers, and combined with the sizes of other original teeth on the gear, comparative measurements can be made.

[0070] Embodiment 7:

[0071] This embodiment is optimized based on the above-mentioned embodiment 1.

[0072] Since there will be inaccuracies in the inspection on the same day after the base layer welding is completed, in order to achieve a more accurate inspection effect, in S3, it is necessary to carry out PT inspection the next day after the base layer forming is completed to ensure that there are no cracks and visually check the welding effect. If there are defects, use an angle grinder to grind and remove the defects, and then repair them.

[0073] Embodiment 8:

[0074] This embodiment is optimized based on the above-mentioned embodiment 1.

[0075] In S3, if the volume of the original tooth is large, during the base layer welding process, a homogeneous body consistent with the original tooth material is added inside the base layer.

[0076] If the volume of the original tooth is large, the volume of the cladding weld is also large, which is prone to cracking. Therefore, adding a homogeneous body consistent with the original tooth material inside the base layer and using a homogeneous sandwich cladding method can reduce the volume of the cladding weld and make it less likely to crack.

[0077] Embodiment 9:

[0078] This embodiment is optimized based on the above-mentioned embodiment 1.

[0079] In order to form a repaired tooth with the same appearance as the original tooth, in S4, the wear-resistant layer is polished, PT-detected and cleaned after cladding.

[0080] Embodiment 10:

[0081] This embodiment is optimized based on the above-mentioned embodiment 1.

[0082] In order to detect the temperature value more accurately, in S2, a temperature gun is used to perform multi-point temperature measurement in the welding area.

[0083] After the yaw ring gear is repaired using this repair method, all indicators meet the requirements and the fan can operate normally.

[0084] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for repairing wind turbine pitch and yaw gears, characterized in that: The following steps are involved: S1. Flaw detection and cleaning: Perform PT flaw detection on the gear to be repaired, then cut, grind and remove all crack sources on the gear, clean it with a cleaning agent, and then perform PT flaw detection again. After passing the test, start welding repair work; S2. Preheating: Heat the area around the welding area uniformly to 100°C through the heater, and then slowly cool it down to 80°C with a thermal blanket; S3, base layer forming: multi-layer and multi-pass cladding welding is adopted by the welding machine, and the welds are arranged along the length direction of the original tooth to form a base layer with a trapezoidal cross section, and then the base layer is lightly polished, PT flaw detection and cleaning are carried out in sequence; S4. Wear-resistant layer cladding: 42CrMo4V special steel is used for multi-layer and multi-pass cladding welding. The welds are arranged along the length direction of the original tooth to form a wear-resistant layer covering the outside of the base layer. The thickness of the wear-resistant layer is controlled between 1mm and 2.5mm.

2. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S2, the heated width is not less than 100 mm.

3. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S3, the base coating is completed when the size of the base coating is uniformly smaller than the original teeth by 1.5 mm±0.5 mm.

4. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S3, during the process of welding and forming the base layer, after each layer is welded, it is gently tapped with a small hammer until the temperature of the layer is less than or equal to 80°C and then the tapping is stopped.

5. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S3, during the base layer welding process, after each welding pass is completed, the temperature is lowered to 100℃-200℃ before the next welding pass is carried out. During the welding process, a small hammer is used to tap the edge of the weld to release the welding residual stress.

6. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S4, when the cladding thickness of the wear-resistant layer is greater than the target value of 0.5 mm-1 mm, the cladding of the wear-resistant layer is stopped, and then a thermal insulation blanket is used to keep the temperature and slowly cool for more than 30 minutes.

7. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S3, PT flaw detection needs to be carried out the next day after the base layer is formed. If there are defects, they should be polished with an angle grinder to remove the defects and then repaired.

8. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S3, if the volume of the original tooth is large, during the base layer welding process, a homogeneous body consistent with the original tooth material is added inside the base layer.

9. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S4, the wear-resistant layer is polished, PT inspected and cleaned after cladding.

10. A method for repairing wind turbine pitch and yaw gears according to claim 1, characterized in that: In S2, a temperature gun is used to measure the temperature at multiple points in the welding area.

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